Patent Publication Number: US-7724146-B2

Title: Magnetically releasable electronic article surveillance tag

Description:
RELATED APPLICATIONS 
     This application is a continuation-in-part of PCT patent application number—PCT/US2005/041813 filed on Nov. 16, 2005, which claims benefit of earlier filed provisional patent application No. 60/628,730 filed on Nov. 17, 2004 titled “Magnetically Releasable Grooved Tack Clutch For Reusable And NonReusable Applications,” the entireties of which are hereby incorporated by reference for all purposes. 
    
    
     BACKGROUND 
     An Electronic Article Surveillance (EAS) system is designed to prevent unauthorized removal of an item from a controlled area. A typical EAS system may comprise a monitoring system and one or more security tags. The monitoring system may create a surveillance zone at an access point for the controlled area. A security tag may be fastened to the monitored item, such as a garment or article of clothing. If the monitored item enters the surveillance zone, an alarm may be triggered indicating unauthorized removal of the monitored item from the controlled area. 
     Security tags are typically attached to the article of clothing using a metal tack having a large head. During attachment operations, the tack may be inserted through the clothing fabric and into a tack shank hole in the security tag where the tack shank is securely retained. During detachment operations, the tag may be released from the security tag and the garment at the point of sale. 
     Security tags may generally comprise one of two types. One type of security tag may be designed for reuse. For example, a security tag may be detached from the monitored item at the point of sale in a manner that does not substantially harm the integrity of the security tag, either externally or internally. Once detached, the reusable tag may be reattached to another item. Another type of security tag may be designed for single use. For example, a security tag may be detached from the monitored item at the point of sale in a manner that typically harms the integrity of the security tag. Once detached, a single-use security tag cannot be reattached again to another item. 
     Both types of security tags may be unsatisfactory for a number of reasons. For example, conventional reusable security tags may be relatively expensive since they are made to be durable enough to withstand the rigors of continuous attaching and detaching from monitored items. Single-use security tags, however, may not be economical, or secure enough to meet the design constraints for a given security system. Consequently, there may be a need for an improved EAS system to solve these and other problems. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1A  illustrates a security tag and a tack assembly in accordance with one embodiment. 
         FIG. 1B  illustrates a security tag assembly in accordance with one embodiment. 
         FIG. 2  illustrates a security tag, a tack assembly and an article in an unfastened position in accordance with one embodiment. 
         FIG. 3  illustrates a security tag, a tack assembly and an article in a fastened position in accordance with one embodiment. 
         FIG. 4  illustrates a first perspective view of a disassembled security tag in accordance with one embodiment. 
         FIG. 5  illustrates a second perspective view of a disassembled security tag in accordance with one embodiment. 
         FIG. 6  illustrates a cutaway view of a security tag and tack assembly aligned with a magnetic detaching device in accordance with one embodiment. 
         FIG. 7  illustrates a security tag inserted into a magnetic detaching device in accordance with one embodiment. 
         FIG. 8A  illustrates an interior view of an upper housing for a security tag in accordance with one embodiment. 
         FIG. 8B  illustrates an interior view of an upper housing with a wedge inserted for a security tag in accordance with one embodiment. 
         FIG. 8C  illustrates an interior view of an upper housing with a wedge and rubber spring inserted for a security tag in accordance with one embodiment. 
         FIG. 8D  illustrates an interior view of an upper housing with a wedge, rubber spring, and tack shank inserted for a security tag in accordance with one embodiment. 
         FIG. 9A  illustrates the partial section A-A of  FIG. 8D  in accordance with one embodiment. 
         FIG. 9B  illustrates a force diagram for components of  FIG. 9A  in accordance with one embodiment. 
         FIG. 9C  illustrates a dimensional diagram for components of  FIG. 9A  in accordance with one embodiment. 
         FIG. 9D  illustrates a second dimensional diagram for components of  FIG. 9A  in accordance with one embodiment. 
         FIG. 9E  illustrates an interior view of an upper housing for a security tag in accordance with one embodiment. 
         FIG. 9F  illustrates an interior view of an upper housing with a wedge, rubber spring, and a tack shank inserted for a security tag in accordance with one embodiment. 
         FIG. 9G  illustrates a dimensional diagram for components of  FIG. 9F  in accordance with one embodiment. 
         FIG. 9H  illustrates the partial section A-A of  FIG. 8D  in accordance with a single use embodiment. 
         FIG. 9I  illustrates the partial section A-A of  FIG. 8D  in accordance with a single use embodiment. 
         FIG. 10  illustrates a set of curves representing pullout force in accordance with several embodiments. 
         FIG. 11  illustrates an interior view of a lower housing for a security tag in accordance with one embodiment. 
         FIG. 12A  illustrates a first view of a wedge for a security tag in accordance with one embodiment. 
         FIG. 12B  illustrates a second view of a wedge for a security tag in accordance with one embodiment. 
         FIG. 13  illustrates a view of a rubber spring for a security tag in accordance with one embodiment. 
         FIG. 14  illustrates a first view of a cross-section taken along line D-D of a reusable security tag with a tack, wedge, and rubber spring in accordance with one embodiment. 
         FIG. 15  illustrates a second view of a cross-section taken along line D-D of a reusable security tag with a tack, wedge, and rubber spring in accordance with one embodiment. 
         FIG. 16  illustrates a third view of a cross-section taken along line D-D of a reusable security tag with a tack, wedge, and rubber spring in accordance with one embodiment. 
         FIG. 17  illustrates a fourth view of a cross-section taken along line D-D of a reusable security tag with a tack, wedge, and rubber spring in accordance with one embodiment. 
         FIG. 18  illustrates a first view of a cross-section taken along line D-D of a security tag with a tack, wedge, rubber spring, and a magnetic detaching device in accordance with one embodiment. 
         FIG. 19  illustrates a second view of a cross-section taken along line D-D of a security tag with a tack, wedge, rubber spring, and a magnetic detaching device in accordance with one embodiment. 
         FIG. 20  illustrates a first view of a cross-section taken along line D-D of a single-use security tag with a tack, wedge, and rubber spring in accordance with one embodiment. 
         FIG. 21  illustrates a second view of a cross-section taken along line D-D of a single-use security tag with a tack, wedge, and rubber spring in accordance with one embodiment. 
         FIG. 22  illustrates a third view of a cross-section taken along line D-D of a single-use security tag with a tack, wedge, and rubber spring in accordance with one embodiment. 
         FIG. 23  illustrates a fourth view of a cross-section taken along line D-D of a single-use security tag with a tack, wedge, and rubber spring in accordance with one embodiment. 
         FIG. 24  illustrates a first view of a cross-section taken along line D-D of a single-use security tag with a tack, wedge, rubber spring, and a magnetic detaching device in accordance with one embodiment. 
         FIG. 25  illustrates a second view of a cross-section taken along line D-D of a single-use security tag with a tack, wedge, rubber spring, and a magnetic detaching device in accordance with one embodiment. 
         FIG. 26  illustrates a third view of a cross-section taken along line D-D of a single-use security tag with a tack, wedge, rubber spring, and a magnetic detaching device in accordance with one embodiment. 
         FIG. 27  illustrates a fourth view of a cross-section taken along line D-D of a single-use security tag with a tack, wedge, rubber spring, and a magnetic detaching device in accordance with one embodiment. 
         FIG. 28  illustrates a fifth view of a cross-section taken along line D-D of a single-use security tag with a tack, wedge, rubber spring, and a magnetic detaching device in accordance with one embodiment. 
         FIG. 29  illustrates a sixth view of a cross-section taken along line D-D of a single-use security tag with a tack, wedge, rubber spring, and a magnetic detaching device in accordance with one embodiment. 
         FIG. 30  illustrates a seventh view of a cross-section taken along line D-D of a single-use security tag with a tack, wedge, and rubber spring, in accordance with one embodiment. 
         FIG. 31  illustrates an interior view of an upper housing for a single-use security tag in accordance with one embodiment. 
         FIG. 32  illustrates a perspective view of a security tag, a tack assembly and an article in an unfastened position in accordance with one embodiment. 
         FIG. 33  illustrates a perspective view of a disassembled security tag in accordance with one embodiment. 
         FIG. 34  illustrates an interior view of part of an upper housing of a security tag in accordance with one embodiment. 
         FIG. 35  illustrates an interior view of part a lower housing of a security tag in accordance with one embodiment. 
         FIG. 36  illustrates a perspective view of a wedge for a security tag in accordance with one embodiment. 
         FIG. 37  illustrates a perspective view of a biasing member for a security tag in accordance with one embodiment. 
         FIG. 38  illustrates a perspective view of a biasing member for a security tag in accordance with one embodiment. 
         FIG. 39  illustrates an interior partial view of an upper housing with a wedge inserted for a security tag in accordance with one embodiment. 
         FIG. 40  illustrates an interior partial view of an upper housing with a wedge and biasing member inserted for a security tag in accordance with one embodiment. 
         FIG. 41  illustrates an interior partial view of an upper housing with a wedge and biasing member inserted for a security tag in accordance with one embodiment. 
         FIG. 42  illustrates a first partial view of a cross-section taken along line D-D of  FIG. 32  of a reusable security tag and a tack in accordance with one embodiment. 
         FIG. 43  illustrates a second partial view of a cross-section taken along line D-D of  FIG. 32  of a reusable security tag and a tack in accordance with one embodiment. 
         FIG. 44  illustrates a third partial view of a cross-section taken along line D-D of  FIG. 32  of a reusable security tag and a tack in accordance with one embodiment. 
         FIG. 45  illustrates a partial view of a cross-section taken along line E-E of  FIG. 32  of a reusable security tag and a tack in accordance with one embodiment. 
         FIG. 46  illustrates a first partial view of a cross-section taken along line D-D of  FIG. 32  of a single-use security tag and a tack in accordance with one embodiment. 
         FIG. 47  illustrates a second partial view of a cross-section taken along line D-D of  FIG. 32  of a single-use security tag and a tack in accordance with one embodiment. 
         FIG. 48  illustrates a third partial view of a cross-section taken along line D-D of  FIG. 32  of a single-use security tag and a tack in accordance with one embodiment. 
         FIG. 49  illustrates a partial view of a cross-section taken along a line corresponding to D-D of  FIG. 32  for a security tag having an alternative embodiment of a biasing member in accordance with one embodiment. 
         FIG. 50  illustrates a partial view of a cross-section taken along a line corresponding to D-D of  FIG. 32  for a security tag having another embodiment of a biasing member in accordance with one embodiment. 
         FIG. 51  illustrates a partial view of a cross-section taken along a line corresponding to D-D of  FIG. 32  for a security tag having another embodiment of a biasing member in accordance with one embodiment. 
         FIG. 52  illustrates a partial view of a cross-section taken along a line corresponding to D-D of  FIG. 32  for a security tag having another embodiment of a biasing member in accordance with one embodiment. 
         FIG. 53  illustrates a partial view of a cross-section taken along a line corresponding to D-D of  FIG. 32  for a security tag having another embodiment of a wedge and biasing member in accordance with one embodiment. 
         FIG. 54  illustrates a first partial view of a cross-section taken along a line corresponding to line D-D of  FIG. 32  of a resettable security tag and a tack in accordance with one embodiment. 
         FIG. 55  illustrates a second partial view of a cross-section taken along a line corresponding to line D-D of  FIG. 32  of a resettable security tag and a tack in accordance with one embodiment. 
         FIG. 56  illustrates a third partial view of a cross-section taken along a line corresponding to line D-D of  FIG. 32  of a resettable security tag and a magnetic device for resetting the security tag in accordance with one embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     Some embodiments may be directed to a security system. The security system may comprise, for example, an EAS system. The EAS system may include a security tag, a detaching device and monitoring system. In general operation, the security tag may include a sensor to emit a detectable signal when it is in the monitored surveillance zone. The security tag may be attached to an item to be monitored, such as a garment or article of clothing. The detaching device may remove the security tag from the item. The monitoring system may monitor a controlled area for the signal to ensure that the monitored item with the security tag is not removed from the controlled area. 
     Various embodiments may include a system that can address the use of reusable and single-use security tags. A system that may address the use of both types of tags may be desirable for modern hypermarket type retail stores. Inexpensive single use security tags make it economical to tag less expensive items, whereas more expensive items can still be tagged with the more expensive reusable type of security tag. Both types of security tags could be removed from the items with the same detaching device as described herein. 
       FIG. 1A  illustrates a security tag and a tack assembly in accordance with one embodiment.  FIG. 1A  may illustrate a security tag  100  and a tack assembly  102 . Security tag  100  may be implemented with a tack retaining system. A tack retaining system may refer to one or more elements arranged to retain tack assembly  102  when inserted into security tag  100 . Security tag  100  may be implemented as a reusable security tag or a single-use security tag depending on the type of tack retaining system implemented for security tag  100 . The embodiments are not limited in this context. 
     In one embodiment, for example, security tag  100  may be implemented using a reusable tack retaining system. A reusable security tag may be detached from a monitored item in a manner that does not substantially harm the integrity of the security tag, either externally or internally. Once a reusable security tag is detached, it may generally be reattached to another item. Detachment indicates the tag is the unlocked condition. 
     In one embodiment, for example, security tag  100  may be implemented using a single-use tack retaining system. A single-use security tag may be detached from the monitored item in a manner that typically harms the integrity of the security tag. Once a single-use security tag is detached, it generally cannot be reattached again to another item. Detachment indicates the tag is in the permanently unlocked condition. 
     In one embodiment, tack assembly  102  may comprise an enlarged tack head  104  and an elongated tack shank  106 . Tack shank  106  may have one or more grooves  108  and a pointed end  112 . In one embodiment, for example, tack head  104  may have a diameter of approximately 0.5 inches, and a thickness of approximately 0.05 inches. Tack shank  106  may be similar in shape to a small pointed nail. In one embodiment, for example, tack shank  106  may be 0.75 inches long, and 0.046 inches in diameter. The grooves  108  may have a diameter of 0.038 inches. The embodiments are not limited in this context. 
     Security tag  100  may be implemented using various materials, to include various types of metals and plastics. For example, tack head  104  may be formed using plastic and/or steel. Tack shank  106  is typically formed using steel. A design constraint for security tag  100  may include the amount of magnetic material that is used with security tag  100 , since the range of some sensors may be reduced by such magnetism. Consequently, tack assembly  102  may be implemented using a plastic material for tack head  104  to reduce the overall amount of steel in tack assembly  102 . Another potential option is to use non-magnetic stainless steel to manufacture tack assembly  102 . The embodiments, however, are not limited to a particular material for tack assembly  102 , as long as they are designed to operate compatibly with each other. 
     In one embodiment, tack assembly  102  may be used to attach security tag  100  to an item. The item may comprise any commercial good, such as a garment, article of clothing, packaging material, digital versatile disc (DVD) jewel case, compact disk (CD) jewel case, glasses, boxes, and so forth. When the item is a garment or article of clothing, pointed end  112  may be inserted through the garment and into security tag  100 . The attachment operation may be discussed in more detail below. 
     In one embodiment, tack assembly  102  may also include additional features, such as a lanyard or security strap attached to tack head  104 . The lanyard or security strap may allow security tag  100  to be used with items where penetration of the item is not desired or possible. For example, packaged items such as sports equipment, electronics and any other product may be secured with the lanyard through a stable portion of the packaging or product itself. The embodiments are not limited in this context. 
     In one embodiment, security tag  100  may be smaller in size than some conventional security tags. In one embodiment, for example, security tag  100  may be approximately 2.6 inches long, 0.8 inches wide, and 0.25 inches thick. With tack assembly  102  inserted into security tag  100 , the thickness may increase to approximately 0.67 inches. The total weight may be approximately 6 grams. The embodiments, however, are not limited to these particular metrics. 
     In one embodiment, security tag  100  may comprise an upper housing  114  and a lower housing  116 . Upper housing  114  and lower housing  116  may be joined at seam  118  to form the closed security tag  100 . In one embodiment, housings  114  and  116  may be made of a semi-hard or rigid material. A usable rigid or semi-hard material may include a hard plastic such as an injection molded Acrylonitrate-Butadiene-Styrene (ABS) plastic, or a plastic such as polycarbonate. If a plastic material is used, the mating of housings  114  and  116  may be accomplished using an ultrasonic weld, snap fitting, or any other suitable joining mechanism desired for a given implementation. The embodiments are not limited in this context. 
     In one embodiment, security tag  100  may comprise a first end  130  and a second end  132 . First end  130  and second end  132  may be partially hollow, with each end having a compartment. First end  130  may have a first compartment to hold a tack retaining system. In one embodiment, for example, the tack retaining system may include a steel wedge shaped member and a rubber bias spring to retain tack shank  106  of tack assembly  102 . First end  130  may also be referred to herein as an “attachment end” or “tack retaining system end.” Second end  132  may have a second compartment to hold a sensor to emit a signal detectable by the monitoring system. An example of a sensor suitable for use with security tag  100  may include the EAS Ultra-Max® narrow label sensor made by Sensormatic® Electronics Corporation (“UltraMax Sensor”). Second end  132  may also be referred to herein as a “detection end.” 
     In one embodiment, first end  130  may comprise a tag head  126 . Tag head  126  may further comprise an upper housing aperture  120  and a concentric rampart  122 . First end  130  may be approximately 0.9 inches long and 0.825 inches wide. The shape may be similar to a half circle with a diameter of approximately 0.825 inches. The embodiments are not limited in this context. 
     In one embodiment, first end  130  may also comprise a detacher interface for use with a detaching device, such as magnetic detaching device  602  as described with reference to  FIG. 6 . For example, first end  130  may include a protrusion  124  having an outer wall  134 . Protrusion  124  may comprise any desired shape, as long as the desired shape appropriately interfaces with the detaching device. In one embodiment, for example, protrusion  124  may have a cylindrical shape, as shown in  FIG. 1A . The embodiments are not limited in this context. 
     In one embodiment, second end  132  may be approximately 1.8 inches long, 0.62 inches wide and 0.22 inches thick. The shape may be similar to a rectangle. The shape and dimensions of second end  132  may allow second end  132  to act as a handle to place the protrusion  124  into the magnetic detaching device described herein. 
       FIG. 1B  illustrates a security tag assembly in accordance with one embodiment.  FIG. 1B  may illustrate another possible embodiment of security tag  100  that is similar to the embodiment described with reference to  FIG. 1A . As shown in  FIG. 1B , second end  132  may be formed 90° with respect to first end  130 . The embodiments are not limited in this context. 
     As illustrated in  FIGS. 1A and 1B , security tag  100  may be implemented using a number of different external shapes or configurations. It may be appreciated, however, that security tag  100  may be implemented using any number of external configurations for a given set of design constraints. The external configuration used for a particular implementation should be made in accordance with the design and configuration of the compatible magnetic detaching device used to detach security tag  100  from a monitored item. In one embodiment, for example, the external configuration shown for security tag  100  in general, and first end  130  in particular, have been designed to interface with the embodiments of a magnetic detaching device  602  as described with reference to  FIG. 6 . The embodiments are not limited in this context. 
     In one embodiment, upper housing aperture  120  of first end  130  may be used to receive tack shank  106  during the attachment operation. The diameter of upper housing aperture  120  may be a little larger than the diameter of tack shank  106  to accommodate the insertion of tack shank  106  during the attachment operation. 
     In one embodiment, concentric rampart  122  may be a rampart defining a space to receive tack head  104 . The diameter of concentric rampart  122  may be a little larger than the diameter of tack head  104  to ensure tack head  104  may be properly seated during the attachment operation. In one embodiment, for example, the internal diameter of concentric rampart  122  may be approximately 0.66 inches. One purpose for concentric rampart  122  is to better secure the article between tack head  104  and security tag  100 . As a result, this arrangement may better resist unauthorized attempts to pry tack assembly  102  away from security tag  100 . The size and configuration of tack head  104 , as well as the shape and size of the mating rampart  122  are not limited in this context. 
       FIG. 2  illustrates a security tag, a tack assembly and an article in an unfastened position in accordance with one embodiment.  FIG. 2  may illustrate the beginning of the attachment operations to fasten security tag  100  to an item, such as an article of clothing. During the attachment operation, pointed end  112  of tack body  106  may be inserted through an article  202 . The size of tack head  104  helps to ensure that article  202  may not be removed from tack assembly  102  without damaging article  202 . 
       FIG. 3  illustrates a security tag, a tack assembly and an article in a fastened position in accordance with one embodiment.  FIG. 3  may illustrate the end of the attachment operation to fasten security tag  100  to an item, such as article  202 . Once pointed end  112  of tack shank  106  is inserted through article  202 , pointed end  112  may be inserted into upper housing aperture  120 . Force may be applied to tack head  104  until tack head  104  is seated in concentric rampart  122 . Tack assembly  102  may remain attached to security tag  100  by a tack retaining system. In one embodiment, for example, the tack retaining system may include a wedge biased by a rubber spring, as discussed in more detail below. Once seated, tack assembly  102  and security tag  100  may be securely attached to article  202 . Once attachment operations have been properly performed, the detachment of security tag  100  from article  202  may be accomplished using magnetic detaching device  602 . 
       FIG. 4  illustrates a first perspective view of a disassembled security tag in accordance with one embodiment.  FIG. 4  illustrates a first perspective view for a disassembled security tag  100  suitable for use as a reusable security tag. The first perspective view illustrates in particular the exterior of upper housing  114 , and the interior of lower housing  116 . 
     In one embodiment, security tag  100  may include a sensor  402 . Sensor  402  may comprise any sensor capable of generating a detectable signal, such as a magnetic sensor, an acoustic magnetic sensor, a Radio-Frequency (RF) sensor, or other type of sensor. In one embodiment, for example, sensor  402  may comprise the UltraMax. Sensor. The signal may be detected by an EAS monitoring system. The EAS monitoring system may include, for example, a transmitter/receiver (“transceiver”) to detect the signals, and inform a monitoring system of the presence or absence of security tag  100  in the surveillance zone. 
     In one embodiment, lower housing  116  may have a sensor compartment  404 . Sensor compartment  404  may be representative of, for example, the second compartment discussed with reference to  FIG. 1A . Sensor compartment  404  may comprise a plurality of walls  416  to define an area large enough for a given sensor. In one embodiment, for example, sensor  404  may be an UltraMax Sensor having the dimensions of 1.73 inches long, 0.46 inches wide and 0.085 inches thick. Other lengths and sizes can accommodate other detection technologies. Walls  416  may correspond to similar walls for upper housing  114 . 
     In one embodiment, lower housing  116  may also have a pocket  1110 , as described with reference to  FIG. 11 . Pocket  1110  may provide a bearing surface  1111 B for a rubber spring  1302 , as described in more detail with reference to  FIG. 13 . The circular inside wall  1113  may guide and secure circular protrusion  809 , such as shown in  FIG. 5  described below, of upper housing  114  when upper housing  114  and lower housing  116  are joined together to form security tag  100 . 
       FIG. 5  illustrates a second perspective view of a disassembled security tag in accordance with one embodiment.  FIG. 5  illustrates a second perspective view for a disassembled security tag  100  suitable for use as a reusable security tag. The second perspective view illustrates in particular the interior of upper housing  114 , and the exterior of lower housing  116 . 
     In one embodiment, upper housing  114  may include a wedge compartment  802  that is formed within protrusion  809 , as described in more detail with reference to  FIG. 8A . Wedge compartment  802  may be representative of, for example, the first compartment discussed with reference to  FIG. 1A . Wedge compartment  802  may comprise a plurality of side walls  803  to define an area large enough for a wedge  1202 R as described in more detail with reference to  FIG. 12A , and a rubber spring  1302  as described in more detail with reference to  FIG. 13 . For example, wedge compartment  802  may be designed to receive and loosely constrain wedge  1202 R and rubber spring  1302 . Compartment  802  may also be defined by a plurality of posts, recesses, or other structures that define an area that receives wedge  1202 R and rubber spring  1302 . Once housings  114  and  116  are joined at seam  118 , the first and second compartments may be closed and sealed. Sensor  402  may be securely contained, although not deformed, within sensor compartment  404 . Wedge  1202 R and rubber spring  1302  may be securely contained within wedge compartment  802 , such as shown in  FIG. 8A  (described below) as well as in  FIG. 5 , thereby forming a tack retaining system. 
     Positioning rubber spring  1302  between wedge surface  1205 R and the bearing surface  1111 B may cause wedge  1202 R to be biased inwardly into wedge compartment  802 . When tack assembly  102  is inserted through upper housing aperture  120  along line  412 , tack shank  106  may intersect tack retaining edge  1213 R of wedge  1202 R, causing wedge  1202 R to pivot approximately about pivot edge  1215 R against the bias of rubber spring  1302 . Tack shank  106  may slide along tack retaining edge  1213 R and be biased by rubber spring  1302  into a passing tack groove  108  of tack shank  106 . During the attachment operation, a portion of tack shank  106  may move into lower housing shank hole  1115 . Once tack retaining edge  1213 R is biased into a tack groove  108  at tack lip  107  (see  FIGS. 8D and 9A ), tack shank  106  cannot be retracted from aperture  120  unless the tack holding strength of the tack retaining system is overcome. In this manner security tag  100  and tack assembly  102  may be locked or fastened together to complete the attachment operation. This may be referred to herein as a “lock condition” or “locked condition.” 
     In one embodiment, lower housing  116  may include a surface  508 . Protrusion  124  may be integrally formed with surface  508 . The diameter of protrusion  124  may be smaller than the size of tag head  126 . In one embodiment, the diameter of protrusion  124  is approximately 0.55 inches, and may protrude 0.45 inches. The smaller size of the protrusion  124  may create a shoulder area  504 . Shoulder area  504  may be relatively flat, and may be used to assist seating first end  130  and protrusion  124  into a magnetic detaching device during the detachment operation. 
     In one embodiment, the detachment operation may refer to detaching or releasing tack assembly  102  from wedge  1202 R of security tag  100 . Once tack assembly  102  is released from wedge  1202 R, tack assembly  102  may be withdrawn from security tag  100 . Once tack assembly  102  has been withdrawn from security tag  100 , article  202  may be removed from tack body  106 , thus completing the detachment operation. This may be referred to herein as an “unlocked condition.” The detachment operation may be described in greater detail with reference to  FIG. 6 . 
       FIG. 6  illustrates a cutaway view of a security tag and tack assembly aligned with a magnetic detaching device in accordance with one embodiment.  FIG. 6  shows a view of security tag  100  being aligned over a magnetic detaching device  602 . Magnetic detaching device  602  is shown in a cutaway view for clarity. Magnetic detaching device  602  may comprise, for example, a magnet assembly  603  and a housing  610 . The housing  610  may be, for example, suitable for countertop mounting where the tag receiving hole  611  is above the surface of the countertop. A different housing with a bezel may be suitable for mounting in a hole in the countertop such that the opening for tag receiving hole  611  is flush or nearly flush with the countertop surface. The embodiments are not limited in this context. 
     In one embodiment, magnetic detaching device  602  may have a tag interface. The tag interface may be arranged to interface with the detacher interface of security tag  100 . In one embodiment, for example, the tag interface may comprise tag receiving hole  611 . The diameter for the opening of tag receiving hole  611  may be designed to accept tag protrusion  124  loosely for easy insertion by the user, yet still assure proper tag location for detachment. The depth of tag receiving hole  611  may be arranged to allow proper detachment of the tack from the tag, which is typically slightly less than the length of the tag protrusion  124 . In one embodiment, for example, the external configuration shown for magnetic detaching device  602  has been designed to interface with the embodiments of security tag  100  as described with reference to  FIGS. 1A and 1B . The embodiments, however, are not limited in this context as long as the detacher interface and tag interface are compatible. 
       FIG. 7  illustrates a security tag inserted into a magnetic detaching device in accordance with one embodiment.  FIG. 7  illustrates security tag  100  when placed within magnetic detaching device  602 . More particularly,  FIG. 7  illustrates security tag  100  and tack assembly  102  as seated within or on magnetic detaching device  602 . This position may facilitate the detachment of tack assembly  102  from security tag  100 . 
       FIG. 8A  illustrates an interior view of an upper housing for a security tag in accordance with one embodiment.  FIG. 8A  shows a detailed view of a wedge compartment  802  of upper housing  114 , and in particular the wedge compartment  802  for a tack retaining system as arranged within end  130 . This arrangement may be suitable for use in both a reusable or single-use security tag. One difference between the two implementations is the shape of the wedge. In a reusable security tag, the wedge  1202 R may have axle protrusions  1221 R and  1222 R as shown in  FIG. 12A , which are not necessarily present in the wedge  1202 S used for a single-use security tag as shown in  FIG. 12B . The use of an “R” suffix to the wedge designator numeral may refer to a tack retaining system suitable for use with a reusable security tag (e.g.,  1202 R,  1213 R, and so forth). The use of an “S” suffix to the wedge designator numeral may refer to a tack retaining system suitable for use with a single-use security tag (e.g.,  1202 S,  1213 S, and so forth). If no wedge designator numeral suffix is used (e.g.  1202 ,  1213 , and so forth), the description may relate to one or both the reusable wedge  1202 R and the single use wedge  1202 S. The embodiments are not limited in this context. 
     As shown in  FIG. 8A , wedge compartment  802  may comprise several internal walls. A tack shank hole  807  may comprise the space in which tack shank  106  can move and occupy along line  412 , such as shown, e.g., in  FIGS. 3-4 . Tack shank hole  807  may extend through upper housing  114 , beginning at aperture  120  and through a top wall  808 A, entering wedge compartment  802  and partially through a front wall  803 C to a top surface  814  of a protrusion  809 . 
     The location of front wall  803 C may vary in accordance with a desired implementation. For example, front wall  803 C may be positioned more distant from back wall  803 D than shown in  FIG. 8A , where it is coincident with a wall  803 T. As shown in  FIG. 8A , wall  803 C is approximately 0.016 inches closer to back wall  803 D than is a wall  803 T. Further, wall  803 C has a semi-circular surface cut through to clear for tack shank hole  807 . The portion of a tack shank bearing surface  803 S most distant from back wall  803 D may comprise bearing wall  803 T. The semi-circular surface may provide several advantages, such as assisting to guide tack shank  106  when inserted, to provide a semi-circular bearing surface  803 S for circular tack shank  106  which provides a slightly higher pullout force (Fpo) relative to having a flat bearing surface. The pullout force Fpo may refer to an amount of separation force between security tag  100  and tack assembly  102  that is needed to forcibly extract tack assembly  102  from security tag  100 . There may be other factors to be considered in locating wall  803 C, as discussed further below. 
     When lower housing  116  is joined to upper housing  114 , tack shank hole  807  extends further into the lower housing shank hole  1115  where hole  807  terminates (see  FIG. 4 ). When tack shank hole  807  is not occupied, surface  1203 , such as shown in  FIG. 9A  described below, of a wedge  1202  may lay flat against top wall  808 A with tack retaining edge  1213  touching or nearly touching front wall  803 C. Wedge  1202  may fit in wedge compartment  802  closely but with sufficient clearance that wedge  1202  is free to pivot approximately about pivot edge  1215 . For example, wedge side  1211 , such as shown in  FIGS. 12A-12B  described below, is movably close to a side wall  803 E, wedge side  1214  (also in  FIGS. 12A-12B ) is movably close to a side wall  803 J, wedge pivot side  1207  (also in  FIG. 12A-12B ) is movably close or touching back wall  803 D, and tack retaining edge  1213  (also in  FIG. 12A-12B ) is movably close to front wall  803 C and covers most of tack hole  807 . In a reusable security tag, wedge axle protrusions  1221 R and  1222 R may loosely reside in their respective recesses  821  and  822  so they can pivot without significant resistance. 
       FIG. 8B  illustrates an interior view of an upper housing with a wedge inserted for a security tag in accordance with one embodiment.  FIG. 8B  shows wedge  1202  as inserted into wedge compartment  802  and lying flat on top wall  808 A. Once wedge  1202  is in place, rubber spring  1302  may be placed in its portion of wedge compartment  802 . In a reusable security tag, protrusions  1221 R and  1222 R may be positioned in their respective recesses  821  and  822 . 
       FIG. 8C  illustrates an interior view of an upper housing with a wedge and rubber spring inserted for a security tag in accordance with one embodiment.  FIG. 8C  shows wedge  1202  and rubber spring  1302  as positioned within wedge compartment  802  in accordance with one embodiment. A side  1304 A, such as shown in  FIG. 9A  described below, of rubber spring  1302  is inserted into wedge compartment  802 , keeping rubber spring surface  1308 D adjacent to back wall  803 D. Rubber spring  1302  is further guided by pocket side walls  803 F,  803 G,  803 H, and  8031 , until rubber spring side  1304 A rests on surface  1205  of wedge  1202 . In one embodiment, the width of rubber spring  1302  may be greater than the width of wedge  1202 , which fits closely in the extended portion of the wedge compartment  802  from sidewall  803 G to sidewall  803 H. In this manner, the location of rubber spring  1302  on wedge  1202  may be controlled. The embodiments are not limited in this context. 
     Controlling the location of rubber spring  1302  may assure that tags built in a production environment have a reproducible rubber spring bias on wedge  1202  for reliable and consistent detaching. The location of rubber spring  1302  may also reduce or prevent the effects of “slamming” in a single-use security tag. Slamming may refer to a user striking the bottom of protrusion  124  against a hard surface, which may cause a single-use security tag to attain a permanent unlock condition without the use of magnetic detaching device  602 . This may occur since the bias of rubber spring  1302  is toward one end of wedge  1202 S. The vertical force caused by slamming may operate on the center of gravity of wedge  1202 S thereby causing wedge  1202 S to twist or rotate under the force of the slam. The effects of slamming may be reduced or eliminated, however, by moving the bias of rubber spring  1302  to the center of gravity of wedge  1202 S, as described with reference to  FIG. 31 . The embodiments are not limited in this context. 
     In one embodiment, the distance from wedge surface  1205  to bearing surface  1111 B is less than the height of rubber spring  1302 . Consequently, rubber spring  1302  may be compressed when upper housing  114  and lower housing  116  are joined to construct security tag  100 . This may cause wedge  1202  to be biased against top wall  808 A of wedge compartment  802 . In a reusable security tag, this may also bias axle protrusions  1221 R and  1222 R into their respective recesses  821  and  822 . 
       FIG. 8D  illustrates an interior view of an upper housing with a wedge, rubber spring, and tack shank inserted for a security tag in accordance with one embodiment.  FIG. 8D  shows another view into wedge compartment  802 . This view is depicted as though lower housing  116  is joined to upper housing  114  where lower housing  116  is transparent. Thus, wedge surface  1203  is biased against top wall  808 A of wedge compartment  802 , as it would be in a completed security tag  100 . 
       FIG. 9A  illustrates a partial section A-A of  FIG. 8D  in accordance with one embodiment. Axle protrusion  1221 R is shown for reference.  FIG. 9A  may be used to assist in describing insertion operations of tack assembly  102  into security tag  100 . As shown in  FIG. 8D  and  FIG. 9A , pointed end  112  of tack shank  106  may be inserted into security tag  100  through aperture  120  and into tack hole  807 . During insertion, pointed end  112  may contact inclined surface  1209  of wedge  1202  causing wedge  1202  to pivot counterclockwise approximately about wedge edge  1215  against the bias of rubber spring  1302  until tack shank  106  begins to slide by the tack retaining edge  1213  of wedge  1202 . Further insertion may cause tack groove  108  and lip  107  of tack shank  106  to come adjacent to tack retaining edge  1213  which is then biased into tack groove  108  against lip  107  by rubber spring  1302 . Accordingly, tack retaining edge  1213  may be positioned within tack groove  108 , thereby preventing tack assembly  102  from being pulled out of security tag  100  unless the holding strength of the tack retaining system is overcome. In this position, tack assembly  102  may be fastened or locked to security tag  100 , and the locked condition is attained. In one embodiment, for example, the wedge angle {acute over (Ø)} may be approximately 34° when in the locked condition. 
       FIG. 9A  also illustrates a feature concerning the detachment process of the reusable tack retaining system.  FIG. 9A  depicts the recess  821  in which protrusion  1221 R resides, and not shown, but by symmetry recess  822  where protrusion  1222 R resides. The depth of the recesses  821 / 822  is the vertical dimension of walls  803 L/ 803 K. During detachment, as the tag  100  approaches the detacher per  FIG. 6 , the wedge  1202 R is urged to rotate counterclockwise about approximately edge  1215 R. As the tag gets closer to seating in the detacher, the magnetic attractive force becomes stronger until wedge  1202 R rotates enough for edge  1213 R to clear lip  107  releasing the tack from the tag. The tag may become fully seated in the detacher (See  FIG. 7 ) immediately after the tack is released. Typically, the tag is fully seated in the detacher, the tag being held in the detacher by the magnetic force attracting the wedge  1202 R, and then the tack is removed from the tag. The tack retaining system may be designed such that when the tag is seated, a given magnetic strength “S” is just sufficient to release the tack (unlock condition), or the magnetic strength may exceed the value “S” by for example 25% and the tack retaining system will still release the tack. An operational problem may arise if the magnetic strength of the detacher far exceeds the value “S”. The wedge may rotate further compressing the rubber spring  1302  to a point where the wedge approaches verticality and the edge  1213 R of wedge  1202 R is attracted to contact wall  1111 B. This may cause protrusions  1221 R and  1222 R to be pulled out of their respective recesses  821  and  822 , and the expanding rubber spring  1302  to push the protrusion portions of edge  1216 R onto walls  816 / 818  which may constitute a permanent unlock condition. To remedy this condition, the dimensioning of the tack restraining system is such that walls  803 L and  803 K are sufficiently long vertically, and the wedge length is sufficient, that when edge  1213 R contacts wall  1111 B, the protrusions  1221 R and  1222 R cannot be pulled out of their respective recesses  821  and  822 . 
     Referring again to  FIG. 9A , one design constraint for a security tag may include the amount of pull force (Fp) needed to forcibly separate tack assembly  102  from security tag  100  without a detaching device  602 . This force may be referred to as the “pullout force” (Fpo). For example, assume a pull force (Fp) in the “tack out” direction is applied to tack assembly  102  in an attempt to separate tack assembly  102  from surface  138  of security tag  100 . This may occur when a person attempts to pull on cloth  202  and tack assembly  102  in a vertical direction away from security tag  100 . Since groove lip  107  of tack groove  108  is engaged with tack retaining edge  1213 , the vertical force pulls on tack retaining edge  1213  which attempts to pivot wedge  1202  clockwise about approximately edge  1215 . Clockwise pivoting of wedge  1202 , however, attempts to put the tack retaining edge  1213  within tack hole  807  while the tack shank  106  is still therein. Consequently, tack shank  106  may become wedged in security tag  100 . This may sometimes be referred to herein as a “wedge effect.” Wedge  1202  will retain tack assembly  102  in security tag  100  unless the tack holding strength of the tack retaining system is overcome (e.g., Fp&gt;Fpo). 
     As shown in  FIG. 9A , when tack assembly  102  is locked in security tag  100  where tack retaining edge  1213  is in contact with lip  107 , there is a certain vertical distance between the bottom of tack head  104  and tag surface  138 . This distance may be referred to as an “initial tack clearance” (ITC). Increasing Fp may cause some yielding and/or deforming of components of the tack retaining system, which results in “additional tack clearance” (ATC) adding to the initial tack clearance. If the components did not yield or deform, there would be no additional tack clearance. Additional tack clearance is typically not desirable because it may expose more of tack shank  106  to potential bending or cutting, thereby making security tag  100  more vulnerable and easier to defeat. There may be several design techniques to accommodate or reduce additional tack clearance, as described in more detail below. 
       FIG. 9B  illustrates a static force diagram for the tack retaining system components of  FIG. 9A  in accordance with one embodiment. In order for Fp not to pull tack assembly  102  out of security tag  100 , there must be an equal but opposite force Fp′ holding tack assembly  102  in security tag  100 . This may describe a static or non-movement condition. If Fp becomes large enough to pull the tack out of the tag while in locked condition, that value of Fp is referred to as the pullout force Fpo as stated earlier. 
     In the static force diagram shown in  FIG. 9B , Fp may refer to the applied pull force on tack assembly  102  from security tag  100 , and Pt-W may refer to the point where tack retaining edge  1213  engages groove lip  107  in groove  108 . Further, the static force diagram and derived static equations assume that all tack restraining system components do not yield or deform, including walls  803 D,  808 A,  803 T, wedge  1202  and tack shank  106 . 
     In accordance with static mechanics, the following equations may be derived:
 
 Fp′=Fp=Fv+Ff;  
 
 Fv=Fa× sin ø;
 
 Ff=β×Fh ; and
 
 Fh=Fa× cos ø.
 
wherein β may represent the static coefficient of friction between the tack shank and wall  803 S/ 803 T. For example, β may approximate 0.5 as determined by experimentation measured at 4 pounds (lbs) and 26 lbs of Fh. These equations may be rewritten in the following form:
 
 Ff=β×Fa× cos ø;
 
 Fp=Fv+Ff=Fa× sin  ø+β×Fa× cos  ø=Fa (sin ø+β×cos ø); and
 
 Fa=Fp /(sin ø+β×cos ø).
 
For a wedge angle ø of 34°, the following may be derived:
 
 Fp′=Fp=Fv+Ff;  
 
 Fa= 1.027 ×Fp;  
 
 Fh=Fa× cos ø=0.851 ×Fp;  
 
 Ff=β×Fh=β×Fa× cos ø=0.426 ×Fp ; and
 
 Fv=Fa× sin ø=0.574 ×Fp.  
 
Based on these equations, Fp will always be countered by an Fp′ that equals Fp, so increasing the value of Fp should cause no movement of tack assembly  102 , that is no additional tack clearance (ATC) occurs. Curve A of  FIG. 10  shows the relationship of additional tack clearance verses Fp for such ideal constraints. Tests for the embodiment shown in  FIG. 8D  have shown that as the pull force Fp continues higher there is a gradual yielding of the tack retaining system components until the tack assembly  102  is forcibly released from security tag  100 . Curve C of  FIG. 10  is an example of how additional tack clearance may occur as a result of tack restraining components gradually yielding under the strain of increasing Fp. By employing certain improvements to the embodiment of  FIG. 8D  yielding curve C, curves much closer to the ideal curve A may be attained, such as curves D, E, F, G, H, and I, as will be discussed below. Concerning the curves A and C of  FIG. 10 , the curves are relative in the information they provide. For example, if the Fp scale only went to 0.5 pounds instead of 160 lbs, curve A and curve C would look very much alike. Also, if the Fp scale went to a million pounds, Curve A and curve C would appear to release at approximately 0 lbs. The scales used herein may encompass values desired to protect merchandise against most human theft attempts on the retail floor. For example, the direct hand to hand pull force a person can generate is about 80 pounds. Therefore the Fpo of a security tag on a garment, where the direct pull of the tack from the tag is a possible defeat mode, should be at least 80 pounds. Generally, the higher the Fpo of a security tag the higher the perceived quality of the tag. Another factor of quality is the additional tack clearance produced by Fp; the less the better. Additional tack clearance affords a potential thief more of the tack shank ( 106 ) or tack head to attack with bending, prying, or cutting devices, for example. The amount of additional tack clearance for different security tags in the industry today, for any given Fp, varies greatly. Good performance of a tag embodiment concerning Fp and tack displacement would be one which yields a curve between curve A and curve B of  FIG. 10 . A good Fpo for a security tag may have a specification value of at least 125 pounds, for example.
 
     As stated above, increasing Fp may cause no additional tack clearance under certain ideal constraints. For the configuration of  FIG. 9A , these ideal constraints may include, but are not limited to, the following: (1) the distance from back wall  803 D to tack bearing wall  803 T does not increase; (2) the diameter of tack groove  108  does not decrease; (3) the wedge  1202  length from pivot edge  1215  to tack retaining edge  1213  does not decrease; (4) the thickness of wall  901  does not decrease; and (5) the vertical distance between surface  136  and surface  138  does not decrease. These ideal constraints are difficult to maintain in practical implementation, however, since all materials yield to some extent when force is applied to them. 
     The first constraint involves the distance from back wall  803 D to tack bearing wall  803 T. Applied pull force Fp may cause groove lip  107  to pull on tack retaining edge  1213  toward top wall  808 A. This may urge wedge  1202  to pivot clockwise back to its pre-tack insertion position. With tack retaining edge  1213  engaged in groove  108  at lip  107 , however, tack  108  prevents horizontal movement of edge  1213  into the solid metal of groove  108  so that wedge  1202  cannot pivot back to the pre-tack insertion position. This may create a jamming or wedging effect, wherein a vertical “tack out” motion of tack retaining edge  1213  cannot occur unless some horizontal motion of tack retaining edge  1213  into tack groove  108  occurs at the same time. As a result, Fp acting on tack retaining edge  1213  may cause a resultant horizontal force (Fh) on groove  108  that causes tack shank  106  to bear against tack bearing wall  803 T (bearing surface  803 S), and wedge pivot edge  1215  to bear against back wall  803 D. A resultant vertical force (Fv) may cause wedge edge  1216  to bear against top wall  808 A. Another resultant vertical force may be frictional force (Ff). The frictional force Ff may bear vertically on bearing wall  803 T (bearing surface  803 S). These walls are all part of the upper housing  114  which is typically a solid molded part made of a material such as ABS plastic. Alternatively, the part may be machined from a solid piece of the material. ABS plastic is resilient to some extent, but it may also deform permanently to some extent when force is applied. Thus under the stress of Fp, the wedge compartment wall  803 D in contact with wedge  1202  and wedge compartment wall  803 T/ 803 S in contact with the tack shank  106  may yield somewhat thereby causing some additional tack clearance to occur. 
     The second constraint involves the diameter of tack groove  108 . In one embodiment, for example, tack shank  106  may comprise a material such as steel. The steel shank may be sufficiently hardened to prevent it from deforming under force Fh as exerted by tack retaining edge  1213  on groove  108 . For example, tack shank  106  may be implemented using steel hardened to a Rockwell Hardness of approximately RC 48. The yield of the tack groove  108  is thus is negligible, provided that the tack retaining edge  1213  is sufficiently softer than RC 48, for example RC 40. If the hardness of the tack shank  106 /groove  108  is sufficiently softer than edge  1213 , more yield and thus more additional tack clearance is expected from this source. This may include extruding of the tack shank  106  at lip  107 , and/or cutting of the shank  106  at groove  108 . 
     The third constraint involves the wedge  1202  length Lw from pivot edge  1215  to tack retaining edge  1213 . Some embodiments may have a wedge hardness of approximately RC 40, and a harder tack having a hardness of approximately RC48. Further, in some embodiments, the angle of tack retaining edge  1213  may comprise approximately 30° ( 1220 ) with a tip end radius of no more than 0.002″ to fit well within the intersection of tack groove  108  and tack lip  107 . The intersection of the lip  107  and the groove  108  is about 90° with an internal radius of no more than 0.002″, and is defined as tack contact point Pt-W per  FIG. 9B . Dimensions are not limited in this context, but the tack retaining edge  1213  must fit compatibly into Pt-W. Under the influence of applied Fp and the resultant force component Fh, the portion of the tack retaining edge  1213  in contact with the tack at Pt-W may deform. The typically softer tack retaining edge  1213  is forced onto/into the typically harder tack contact point Pt-W, and as Fp increases, edge  1213  forms around and into Pt-W taking the inverse shape of the Pt-W contact area of the tack. The result is that a concave semi-circular ledge is formed in the tack retaining edge  1213  that conforms to and mates with up to ½ of tack lip  107 , and around part of groove  108  and part of the shank  106  in the contact area. Essentially, with proper hardness and relative hardness of the wedge and tack shank, a form fitted seat for the tack lip  107  may be created. The size and depth of the semi-circular ledge (seat) is dependent upon the maximum Fp imposed as well as the hardness values selected for the wedge and for the tack. The more Fp applied, the larger the form fitted seat that is created (up to ½ of tack lip  107 ), and typically the larger the retaining strength of the tack retaining system. If wedge  1202  is made of a much harder material such as RC 58, tack retaining edge  1213  may not form about the contact area. Rather, the RC 58 wedge  1202  under the influence of Fv may shear off a softer tack (RC 48) at Pt-W. If the wedge and thus edge  1213  hardness is RC 30, the semi-circular ledge may form but potentially strip out or extrude under low values of Fp because edge  1213  is too soft. If the wedge hardness is about RC 48 and the tack hardness is about RC 40, the semi-circular ledge will form to some extent but the tack may partially extrude with increasing Fp. Hardness and relative hardness of the wedge  1202  and tack shank  106  may be of different values and the tag/tack will function normally up to an Fp of about 15 pounds, but the Fp/additional tack clearance curves may vary greatly. In one embodiment, a balanced result may be achieved at a wedge hardness of RC 40 and a tack hardness of RC 48. Other hardness&#39;s may produce desired balanced results, and the values are not limited in this context. Thus the wedge length Lw may be reduced by the depth of the formed semi-circular ledge and cause some permanent additional tack clearance. 
     The fourth constraint involves the thickness of wall  901 . Compression of typically solid plastic wall  901  is relatively minor for values of Fp of up to &gt;200 pounds and thus adds negligibly to the additional tack clearance. Edge  1216  may be forced against wall  808 A by a portion of a resultant force Fv, but the effect on additional tack clearance is relatively minor and may disappear completely when the wedge angle is 0°. Compression of wall  901  under the net separation force Fp may not be significant compared to the net additional tack clearance. 
     The fifth constraint involves the vertical distance between surface  136  and surface  138 . The distance between surface  136  and surface  138  may tend to decrease slightly since the separation force Fp is between the entire surface  138  and the entire under side of tack head  104 , and further, tack shank  106  is engaged with the plastic walls under surface  136  (e.g.,  808 A and  803 S). Because surfaces  136  and  138  are offset at rampart  122 , the housing may tend to yield resiliently and/or deform at the offset, and surfaces  136  and  138  may tend to be drawn together under the force Fp. Proper design of wall thicknesses and diameter of rampart  122  may prevent this issue from adding any significant amount of additional tack clearance for Fp values of well over 100 pounds compared to the net additional tack clearance. If there was no rampart  122 , this issue would not exist. 
       FIG. 9C  illustrates a dimensional diagram for components of  FIG. 9A  in accordance with one embodiment.  FIG. 9C  shows the dimensions and initial conditions with security tag  100  and tack assembly  102  in a locked condition and with a small value of Fp applied just sufficient to cause tack retaining edge  1213  is engaged with lip  107 . More particularly,  FIG. 9C  may show various dimensions of wedge compartment  802 , such as the length (Lw) of wedge  1202  from edge  1215  to Pt-W that is inside tack groove  108  under groove lip  107 , and the horizontal length (La) from back wall  803 D to a point directly below Pt-W, which is set to 0.195 inches by design for the embodiment of  FIGS. 8D and 9A . From these given dimensions, the wedge angle {acute over (Ø)} is calculated to be 34°, and the additional tack clearance possible is 0.131 inches, barring an over rotation issue to be explained further below. It is worthy to note that the additional tack clearance dimension of 0.131 inches corresponds substantially with the notch of curve C in  FIG. 10 . Wedge  1202  may need to lie flat on wall  808 A for the additional tack clearance of 0.131 inches to be realized. Correspondingly, wedge  1202  should pivot approximately about edge  1215  from {acute over (Ø)}=34° to {acute over (Ø)}=0°. This means that the Lw of 0.235 inches lies flat in a length of La set to 0.195 inches. This is a dichotomous condition unless some constraints yield. In fact, under an applied Fp of 65 pounds, the wedge does lie flat on wall  808 A in the embodiment of  FIG. 8D . At an Fp of 65 pounds, semi-circular ledge having a depth of approximately 0.020 inches forms in tack retaining edge  1213  about tack groove  108 , groove lip  107 , and tack shank  106 . This means the Lw reduces from 0.235 inches to 0.215 inches. At the Fp of 65 pounds, a depression of about 0.010 inches develops in wall  803 T ( 803 S), and further, wall  803 D develops a depression of about 0.010 inches made by edge  1215  and wedge surface  1207 . Consequently, dimension La increases from 0.195 inches to 0.215 inches. Accordingly, wedge  1202  fits flat on wall  808 A where Fp is equal to 65 pounds due to the net yield of tack retaining edge  1213 , walls  803 T ( 803 S), and back wall  803 D. 
     The aggregate yield of all the tack retaining system components is incremental with each increment of force Fp applied. Thus, a first increment of Fp from 0 will cause a first increment of additional tack clearance. For example, when Fp increases from 0 to five pounds, the tack clearance may increase from 0 to 0.0033 inches, and so forth. This would produce the linear curve B of  FIG. 10 . This curve rate of 1500 pounds/inch approximates the curve of some conventional security tags. The increment of additional tack clearance, however, typically becomes larger per the same increment of Fp as Fp becomes larger. Curve C of  FIG. 10  may illustrate this non-linearity. 
     By attempting to forcefully separate tack assembly  102  from tag  100 , one or more of the tack retaining system components may yield slightly and cause some additional tack clearance. There are typically two types of yield, referred to as “resilient” and “permanent.” The yields of the metal elements (e.g., metal tack and/or metal wedge) as previously discussed are almost totally permanent. The metals may permanently deform and therefore the yield contribution to additional tack clearance becomes permanent. The yields of the plastic elements, however, may have both resilient and permanent components. Some of the yielding by the plastic elements contributing to the additional tack clearance may be recoverable when Fp is removed, while some is not. The net additional tack clearance for a given pull force Fp will therefore have a permanent component and a recovered component. For example, for a pull force Fp of 50 pounds that is less than or equal to the Fpo, the additional tack clearance may comprise approximately 0.040 inches. When Fp is removed, however, the additional tack clearance may revert to 0.020 inches. This means that there is a permanent additional tack clearance of 0.020 inches, and a resilient (recoverable) additional tack clearance of 0.020 inches. A second applied Fp should not cause further permanent additional tack clearance unless the second Fp is greater than the first Fp. Typically, the largest normal usage Fp is less than 20 pounds, and the permanent additional tack clearance is less than 0.007 inches. When added to the initial tack clearance of typically 0.040 inches, the permanent additional tack clearance is not significant. Experiments have shown that some embodiments may have a permanent additional tack clearance of between 25-80% of the net additional tack clearance, dependent upon the Fp applied. 
     The resulting relationship of the additional tack clearance as a function of the applied force Fp is presented as curve C of  FIG. 10 . It is worthy to note that curve C lies well outside the desired area between curve A and curve B. At an applied force Fp of approximately 65 pounds, the additional tack clearance may comprise 0.131 inches corresponding to the notch in curve C. The additional tack clearance from the notch to the knee in curve C is a result of a slight increase in Fp causing the tack to move as much as an additional 0.032 inches beyond where the wedge angle is 0°. This occurs because after the wedge rotates clockwise to 0° about approximately edge  1215 , it may further rotate clockwise about edge  1217  when it contacts wall  808 A until wedge surface  1209  lies flat on wall  808 A. This rotation about edge  1217  is referred to herein as “over rotation.” The resultant additional downward movement of edge  1213 , in contact with lip  107 , is the additional tack clearance of up to 0.032 inches between the notch and knee of curve C. As this occurs, edge  1215  moves vertically scraping wall  808 D which may offer some resistance to over rotation. The portion of curve C from 65 pounds at the knee to 105 pounds at Fpo is a result of groove  108  and lip  107  being forced through the opening between the semi-circular ledge formed on wedge tack retaining edge  1213  and surface  803 S when the wedge angle is at 0° or less due to over rotation. When the wedge angle is at about 0°, the semi-circular ledge in tack retaining edge  1213  may be fully formed around one side of tack groove  108  and under lip  107  and the opposite side of tack groove  108  and lip  107  may be pressed into and somewhat deform surface  803 S. Thus, in order for the tack shank  106  to be pulled through the “groove  108  size” opening, the opening must be forcibly enlarged. In the embodiment described with reference to  FIGS. 8D ,  9 A,  9 B, and  9 C, the pull force Fp required to pull tack shank  106  through the “groove  108  size” opening may therefore equal approximately 105 pounds (release point of curve C). The process of pulling tack shank  106 , groove  108  and groove lip  107  through the “groove  108  size” opening may include extruding some or all the semi-circular ledge from tack retaining edge  1213 , extruding some or all of surface  803 S, extruding some or all of groove lip  107 , or causing the plastic walls in contact with wedge  1202  to yield further. The net yield from the knee to Fpo is additional tack clearance of about 0.030 inches as shown in curve C of  FIG. 10 . 
     Although the embodiment described with reference to  FIGS. 8A ,  8 B,  8 C,  8 D,  9 A,  9 B,  9 C, and curve C of  FIG. 10  may be used in an EAS security system, the embodiment may have some characteristics that can be improved upon. These characteristics may include: (1) curve C of  FIG. 10  is outside of the desired area between curve A and curve B; (2) the Fpo is not more that the desired 125 pounds; (3) wedge  1202  and tack  100  may become substantially jammed and cannot be detached with the detacher of  FIG. 6  when Fp pulls the wedge  1202  to about 250 or lower, which is primarily a function of a frictional force Ff′ described below; (4) after more than a certain value of Fp is applied and then removed, and the tag is “un-jammed”, the wedge will not re-catch the tack groove lip  107 ; (5) over rotation causes additional tack clearance after the wedge  1202  angle has reached 0°; (6) the single use configuration may be manipulated to the permanent unlock condition with a magnetic detacher weaker than at least strength “S”. 
     To detach the tack  100  from the tag  102 , the wedge  1202  must be in a “free condition,” which may refer to freely rotating under the influence of the detacher of  FIG. 6 . The garment being protected may offer a small resistance to the wedge attaining the free condition. For example, the garment being protected may fit snugly between the tack head and tag (see  FIG. 3 ) providing a small “tack out” pressure on the tack causing tack retaining edge  1213  to be held in the groove  108  at lip  107  such that the detacher of  FIG. 6  may not readily release the tack retaining system. A slight “tack in” finger pressure (Fi) on the tack head will cause the tack to move 0.003″ to 0.004″ which is sufficient to release the wedge to the free condition, allowing wedge edge  1213  to be rotated to the unlock position when the tag is positioned on the detacher per  FIG. 7 . Requiring a small Fi on the tack head to detach the tack from the tag is characteristic of virtually all magnetically releasable ball clutches used on security tags today and it is seldom if ever a problem. This “tack out” pressure provided by the garment is herein referred to as “garment pressure”. 
     When in the free condition, the only tack retaining system restraint on the wedge  1202  to keep it from rotating is the bias of the rubber spring  1302 , which can be overcome by the detacher of  FIG. 6  to release the tack. A jammed wedge  1202  can be forced to the free condition by pushing on the tack head, thus pushing the tack shank  106  into the tag  102  by hand. The push in force (Fi) required depends on more than one factor, but primarily upon the amount of Fp applied. At a wedge angle of about 34°, the wedge may be in the free condition. As Fp is applied the wedge angle reduces as the plastic walls and the wedge resiliently yield and/or deform. From the previously derived equations, the frictional force Ff (Ff=Fp×β×cos {acute over (Ø)}/sin {acute over (Ø)}+β×cos {acute over (Ø)}) resists any movement of the tack, and the vertical force Fv (Fv=Fp×sin {acute over (Ø)}/sin {acute over (Ø)}+β×cos {acute over (Ø)}) strains to hold the tack in the tag. These forces are effectively in the “tack in” direction opposing the Fp applied. At some point the Fp is removed. The resilient portion of the net yield now attempts to recover. This recovery force Fh′ is primarily horizontal (plastic recovering back towards its original pre-pull position) and applies resultant forces on the wedge and tack. A new Ff′ (Ff′=Fh′×β) now exists resisting any movement of the tack. A new Fv′ (Fv′=Fh′×tan {acute over (Ø)}) now exists in the “tack in” direction. If Fv′ is larger than Ff′, the net force is in the “tack in” direction and the tack and wedge will move to the free condition without requiring any hand push in force (Fi) on the tack head. If Ff ″ is larger than Fv′, the net force does not allow movement of the tack and wedge and the tack retaining system will not move to the free condition automatically but will require some amount of Fi on the tack head to attain the free condition (e.g., un-jam the tack). Tests have shown that, for example, no hand push Fi on the tack is required to attain free condition after an Fp of about 15 lbs has been applied and then removed. After an Fp of 20 pounds, the Fi required to attain the free condition is about 5 pounds. After an Fp of 40 to 50 lbs, a Fi of about 15 lbs is required (wedge angle of about 20°) to attain free condition. After an Fp of 65 lbs (wedge angle=0°), a Fi of about 35 lbs is required to attain free condition. 
     Thus it can be appreciated that the frictional force Ff′ between tack shank  106  and surface  803 S/wall  808 T may not always allow wedge  1202  and tack assembly  102  to automatically retreat to the free condition. Rather, the frictional force Ff′ may need to be overcome by a force Fi on the tack head to put wedge  1202  in the free condition. The particular amount of Fi required to cause the tack retaining system to reach the free condition may vary with the Fp applied and corresponding wedge angle {acute over (Ø)} attained, and to some extent the slope and shape of lip  109 . Other factors could involve the time elapsed between Fp and Fi applied, and the difference in temperature when Fp and Fi are applied. Thus a desirable characteristic is to have little or no Fi required when in normal use where Fp could reach 20 to 30 lbs or when even more Fp is applied (e.g., Fi required should be minimized). 
     The discussion of the jamming characteristic (3) above describes typical results for the subject embodiment of  FIGS. 8D and 9A , where the housings  114  and  116  are made of ABS plastic, the tack shank  106  has two circular grooves  108  about tack shank  106  that are approximately 0.040 inches long and spaced about 0.040 inches apart, the tack shank hardness is approximately RC 40, the wedge hardness is approximately RC 45, the surface of the grooves  108  are parallel to the surface of shank  106  and 0.003″/0.004″ deep, both groove lips  107  and  109  are at an angle of 90° with respect to the shank  106  surface, and the first groove lip  107  is about 0.12 inches from the point. 
     In some embodiments, for example, it may be desirable to limit the wedge angle to approximately 15°or higher. When the semi-circular ledge is formed by wedge angles of about 15° or less, and then tack assembly is pushed back to the free condition by Fi, the semi-circular ledge may not “re-catch” groove lip  107 , thus the tack could easily be removed from the tag by hand. This would be an easy form of defeat if an unauthorized user could pull on tack assembly  102  with sufficient force to cause the wedge angle to reach about 15° or less. One reason that this problem can occur is that the formed face of wedge tack restraining edge  1213  can have a length of about 0.011 inches under the semi-circular ledge. When tack assembly  102  is pushed back into security tag  100 , the yield of the plastic recovers somewhat so the angle that the formed end of the semi-circular ledge engages tack groove  108  is different than when it was formed. The depth of groove lip  107  is about 0.003 inches. This means that the wedge angle cannot be less than arctan 0.003/0.011=15°. The value can be different for different hardness values of tack assembly  102  and wedge  1202 , and different amounts of plastic yield recovery. 
     In some embodiments, for example, it may be desirable to prevent wedge  1202  from pivoting beyond 0°. When wedge  1202  rotates clockwise from 34 ° to 0° it is flat on top wall  808 A as is wedge edge  1217 . Additional Fp may be sufficient to cause wedge  1202  to rotate further clockwise about edge  1217 . As a result, wedge  1202  may pivot clockwise further about edge  1217 , causing edge  1215  to then move primarily vertically and scrape back wall  803 D. Once the pivoting about edge  1217  begins, the semi-circular ledge of edge  1213  may move down as much as the thickness of the wedge  1202  and away slightly from tack lip  107 /groove  108 , causing the gripping pressure on the tack groove  108  to be reduced and thus less extrusion of the semi-circular ledge of edge  1213  and wall  808 S required to reach pullout. Pivoting about edge  1217  may cause the tack retaining system to have as much as 0.032 inches more additional tack clearance and a lower pullout force. Curve C of  FIG. 10  shows this additional tack clearance as the distance between the notch and the knee. If the wedge angle was limited to for example 15° or higher, and/or if the wedge surface  901  was completely supported, no pivoting about edge  1217  could occur and Fpo would not be affected. 
     Referring again to  FIGS. 8D ,  9 A, and  9 I,  FIG. 9I  illustrates a partial section A-A of  FIG. 8D  in accordance with one single-use embodiment.  FIG. 9I  may aid in describing the ratcheting effect in a single-use tack retaining system. A potentially undesirable characteristic of the embodiment of  FIG. 8D  and  FIG. 9I  is that the single use tack retaining system is subject to possible defeat by tack manipulation. Assume the configuration of  FIG. 9A  as a reusable (R) tack retaining system only. The wedge  1202 R is constrained to rotational movement about the axle protrusions  1221 R and  1222 R. When the tag  100  is placed in the magnetic detacher of at least sufficient strength “S”, the wedge rotates enough (possibly requiring a slight push down on the tack head to counteract garment pressure) against the bias of rubber spring  1302  so that tack retaining edge  1213 R clears lip  107  and the tack  102  can be withdrawn from the tag  100 . When the tag is removed from the magnetic detacher, it reverts to the rest condition. 
     In the single use configuration of  FIG. 9I , the desire is to release the tack assembly  102  from the tag  100  by placing the tag  100  onto a magnetic detacher of at least sufficient strength “S”. The wedge  1202 S rotates and edge  1216 S translates enough (possibly requiring a slight push down on the tack head to counteract garment pressure) against the bias of rubber spring  1302  so that tack retaining edge  1213 S clears lip  107 , the wedge  1202 S rotates to be parallel with tack shank  106 , and the tack  102  can be withdrawn from the tag  100  (the tag went from lock condition to permanent unlock condition). When the tag is removed from the magnetic detacher, it stays in the unlocked condition permanently. 
     One difference between the reusable configuration and the single use configuration is the translational movement of the wedge  1202 S required to attain the permanent unlock condition. As can be seen in  FIG. 9I , the wedge edge  1216 S is not restrained from moving to the right except for the frictional force at the contact point where edge  1216 S rests on wall  808 A. This frictional force is dependent upon the vertical component of the compression force bias of rubber spring  1302  and a related coefficient of friction ω. Further, there is a horizontal component of the compression force of rubber spring  1302  which tends to push the wedge edge  1216 S to the right from its first position, which may cause the edge  1216 S to move to the right until the frictional force and the horizontal component of force are equal. If the tack is pushed in beyond the lock condition so groove  108  slides on edge  1213 S and then further so lip  109  pushes edge  1213 S to the left by the depth of the groove  108 , the edge  1216 S may move slightly to the right to a second position. At this point, if the tack is pulled in the “tack out” direction, edge  1213 S will catch in lip  107  and further pulling may drive the edge  1216 S back to a point where edge  1215 S contacts wall  808 D as shown in  FIG. 9I . If the tack is pulled so that edge  1213 S just falls back in groove  108 , however, the edge  1213 S may remain in the second position. The result is that edge  1213 S has been moved to the right slightly by manipulating the tack. If the tag is placed on a detaching magnet of less strength than “S”, and this simple push-pull manipulation of the tack is repeated causing edge  1213 S to be lifted and lowered over lip  109 , the magnetic bias of the lesser magnet may allow the edge  1216 S to be “ratcheted” to the right until the wedge  1202 S is advanced to the permanent unlock condition. Ratcheting is thus a form of defeat similar to “slamming” and should be corrected. 
     It is worthy to note that before the tack is inserted, wedge  1202 S surface  1203 S lies flat on wall  808 A, biased to wall  808 A by the compression force of rubber spring  1302 . When the tack is inserted to the point where the wedge is at approximately 34°, edge  1215 S may be slightly to the right of wall  808 D due to the relative vertical and horizontal components of the rubber spring compression force on the wedge  1202 S. If this condition exists, the first position of edge  1216 S may not be when edge  1215 S is touching wall  808 D as is shown in  FIG. 9I , but slightly to the right. 
     One aspect of this issue is that there may be an instability of the position of the wedge  1202 S because edge  1216  may be moved along horizontal surface  808 A by manipulating the tack thereby making it possible attain the permanent unlock condition by using a detacher of less strength than the proper detacher of at least strength “S”. 
       FIG. 9D  illustrates a second dimensional diagram for components of  FIG. 9A  in accordance with one embodiment.  FIG. 9D  may be useful in describing a first of several possible modifications that have been implemented to improve the operation of the embodiment shown in  FIGS. 8A ,  8 B,  8 C,  8 D,  9 A,  9 B,  9 C,  9 I, and curve C of  FIG. 10 . For example, to eliminate the re-catch characteristic (4) and the over rotation characteristic (5) which depend on the wedge  1202  attaining angles of 15° or less, and greatly improve the jamming characteristic (3), a first modification may include installing a wedge stop (e.g., wedge stop  902  shown in  FIG. 9D , and other FIGS. discussed below) in order to keep the wedge angle from becoming less than 22°. Wedge stop  902  may reduce the additional tack clearance from 0.131 inches at 0° to 0.043 inches at 22°, as shown as ATC 2  in  FIG. 9D  (0.131 inches−0.235 inches× sin 22°=0.131 inches−0.088 inches=0.043 inches). It is worthy to note that derived dimensions herein discussed are approximate due to the manufacturing and yield tolerances of the tack retaining system components. If adding the wedge stop  902  was the only modification made, the Fpo may be reduced. Consider  FIG. 9D  where the wedge surface  1205  angle rotates to 0° compared to where it rotates to only 22°. The net amount of horizontal yield of the tack retaining system is a measure of the force holding the tack between the wedge edge  1213  and wall  803 T, e.g., for wedge  1202  to rotate from 34° to 0°, the net horizontal yield becomes 0.235 inches× cos 0°−0.235 inches× cos 34°=0.235 inches−0.195 inches=0.040 inches (See HY 1  in  FIG. 9D ). The net amount of horizontal yield of the tack retaining system with wedge stop  902  when wedge  1202  rotates from 34° to 22° may be 0.235 inches× cos 22°−0.235 inches× cos 34°=0.218 inches−0.195 inches=0.023 inches (See HY 2  in  FIG. 9D ). Therefore, the aggregate horizontal yield imposed may be reduced from 0.040 inches to 0.023 inches, thus reducing the size of the formed seat for lip  107 /groove  108  in the edge  1213 , and thus reducing the amount of extrusion required to release the tack, e.g., the pullout force Fpo may be reduced. This arrangement may solve the issues of characteristics (4) and (5) and improve characteristic (3), but the pullout force possible may be further reduced and must be compensated for by further Fpo enhancement modifications. 
       FIG. 9E  illustrates an interior view of an upper housing for a security tag in accordance with a second embodiment.  FIG. 9E  shows a detailed view of an improved wedge compartment  802  of upper housing  114 . In particular, the wedge stop  902  is shown, a “cored out” area is shown as well as several other features described below. This arrangement is suitable for use in both a reusable or single-use tag.  FIG. 9F  illustrates an interior view of an improved upper housing with a wedge, rubber spring, and a tack shank inserted for a security tag in accordance with a second embodiment. The rubber spring  1302  in  FIG. 9F  is shown compressed as if the lower housing  116  was attached to the preferred upper housing  114  forming a complete tack retaining system. 
       FIG. 9G  illustrates a dimensional diagram for components of  FIG. 9F  in accordance with a second embodiment.  FIG. 9G  is a partial cross section A-A of  FIG. 9F  showing some dimensions and may be instrumental in describing improvements to the embodiment of  FIGS. 8A ,  8 B,  8 C,  8 D,  9 A,  9 B,  9 C,  9 I, and curve C of  FIG. 10 . A second modification to improve the curve C characteristic (1) and Fpo characteristic (2) above, and to compensate for the loss of Fpo caused by introducing the wedge stop  902 , may be implemented. La may be reduced from 0.195 inches of  FIG. 9D  to 0.185 inches of  FIG. 9G  to help establish a higher initial wedge angle {acute over (Ø)} in an effort to further improve curve C and Fpo. Further, the initial Lw may be increased from 0.235 inches of  FIG. 9D  to 0.240 inches of  FIG. 9G . Initial wedge angle was thus increased from 34° to 39.6°. These changes rendered a maximum possible additional tack clearance, if wedge stop  902  was not incorporated, from 0.131 inches of  FIG. 9D  to 0.153 inches of  FIG. 9G  (barring the issue of over rotation as explained earlier). The net horizontal yield when the wedge  1202  rotates from 39.6° to 22° is now equal to (0.240 inches× cos 22°−0.024 inches× cos 39.6°=0.223 inches−0.185 inches=0.038 inches) 0.038 inches (See HY 3  of  FIG. 9G ), which is improved over the 0.023 inches discussed above in the first modification. Yet another improvement is that the possible additional tack clearance has been reduced from 0.131 inches when the wedge angle rotated from 34° to 0° per  FIG. 9C , to only 0.063 inches when the wedge angle rotates from 39.6° to 22° (0.240 inches× sin 39.6°−0.240 inches× sin 22°=0.153 inches−0.090 inches=0.063 inches), as indicated by ATC 3  in  FIG. 9G . Wall  803 C is made coincident with wall  803 T as seen in  FIG. 9E  since tack shank  106  is well supported by the increased length of tack hole  807  (From  FIG. 8A  to  FIG. 9E ) which now extends through wedge stop  902 . Another salient reason was to improve issues concerning ultrasonic welding. Wedge stop  902  sloped top surface may support wedge surface  1209  prior to tack entry. A third modification to further improve characteristics (1) and (2) above, and to compensate for the loss of Fpo caused by introducing the wedge stop  902 , may be implemented. The embodiment shown in  FIG. 9E  may be molded using hi-impact ABS plastic or polycarbonate plastic to reduce the amount of plastic yield even more to improve curve C of  FIG. 10  and the Fpo. A fourth modification to further improve characteristics (1) and (2) above, and to compensate for the loss of Fpo caused by introducing the wedge stop  902 , may be to change the tack and wedge hardness. Typical security tacks in use today have a hardness of approximately RC 40. The wedge of the embodiment of  FIG. 8D  has a hardness of approximately RC 45. There is a tendency therefore for the wedge to cut and/or extrude the softer tack under the stress of Fp, and the semi-circular ledge may not form well in the edge  1213 . This may lead to a lower Fpo than if the ledge was formed better. Tests have indicated that higher values are possible with a tack hardness of approximately RC 50 and a wedge hardness of approximately RC 43, thus this change may improve curve C of  FIG. 10 . 
       FIG. 9H  illustrates the partial section A-A of  FIG. 8D  in accordance with a second single-use embodiment.  FIG. 9H  may be useful in describing the effect of sloped surface  808   a  on the wedge  1202 S in a single-use embodiment. Ratcheting concerns the single-use tack retaining system only, referring to  FIGS. 9H and 9I , with some reference to  FIG. 9E . In one embodiment, a portion of top wall  808 A may be sloped at approximately 22° from horizontal beginning approximately 0.032 inches from back wall  803 D as shown in  FIG. 9H  (in contrast to no sloped surface in  FIG. 9I ). Before the tack  102  is inserted, wedge  1202 S is biased flat on wall  808 A by the compression force of rubber spring  1302  as stated before, with edge  1216 S touching or virtually touching wall  808 D directly above sloped surface  808   a . The sloped portion may comprise surface  808   a  as shown in  FIG. 9H . When tack shank  106  is inserted to where the wedge angle is approximately 34°, the edge  1216 S of the wedge pivot end rests on the sloped surface  808   a . When tack shank  106  and wedge  1202 S are in the locked condition, edge  1216 S is approximately 0.018″ from back wall  803 D resting on the sloped surface  808   a  in the first position. As described earlier concerning  FIG. 9I , the compression force of the rubber spring  1302  has a net horizontal component that urges edge  1216 S to the right, and the compression force has a net vertical component that, coupled with a coefficient of friction ω, provides a frictional force on edge  1216 S that urges no movement. If the horizontal force component overcomes the frictional force, edge  1216 S will move to the right until the net vertical component diminishes to where the frictional force and the net horizontal force are equal. When the sloped surface  808   a  is added, another component of force on edge  1216 S is added urging edge  1216 S to move to the left. This bias to the left is a function of at least the net vertical component of the compression force of rubber spring  1302 , and the angle of the sloped surface  808   a , and a coefficient of friction ω. The bias to the left plus any frictional force may counteract the bias to the right. If the angle of the sloped surface  808   a  is sufficient, the bias to the left may overcome the bias to the right. If the tag  100  is placed on a magnetic detacher of sufficient strength “S”, the wedge  1202 S may be rotated and attracted sufficiently to overcome the net bias to the left and translate edge  1216 S off of sloped surface  808   a  and onto flat surface  808 A where resistance to the translational movement of edge  1216 S may become much less because the bias to the left has been eliminated. Thus a condition has been established that the magnetic detacher strength of at least “S” is required to translate edge  1216 S from the sloped surface  808   a  to the flat surface  808 A. The sloped surface is equally effective in the configuration of  FIGS. 9E and 9F  and so it may be adapted. The only difference is that the wedge angle when in locked condition (i.e., 39.6° versus  34 °) causes a small difference in the distance that edge  1216 S must traverse on surface  808   a  to get to surface  808 A (0.016 to 0.013 inches in the embodiment of  FIG. 9F ). A further improvement is introduced by removing or “coring out” (See “CO” in  FIG. 9E  and  FIG. 20 ) all or a portion of wall  901  from surface  808 A so that edge  1216 S does not slide on a surface  808 A after it translates off of sloped surface  808   a  shown in Fig. E, but “falls” into the cored out hole shown in  FIG. 9E  and  FIGS. 14 through 31 , which offers no resistance to translational movement of edge  1216 S or rotational movement of the wedge  1202 S, so that the whole wedge  1202 S immediately begins a virtually uninhibited counterclockwise rotation around the expanding rubber spring to the permanent unlock condition. Thus, a threshold has been established whereby a magnetic detacher of at least strength “S” is required to advance the edge  1216 S over the end of sloped surface  808   a  (ledge  808   b ) and into the uninhibited rotation of the wedge  1202 S, aided by the expanding rubber spring  1302 , to the permanent unlock condition. The same sloped surface  808   a  may prevent ratcheting. If tack shank  106  has sufficient tack clearance and is pushed in and ratcheting is attempted, wedge edge  1216 S may move to a second position slightly to the right of the first position but still on sloped surface  808   a . When the tack shank  106  is pulled back to its first position, the wedge edge  1216 S may return to its first position due to the sufficient slope of sloped surface  808   a . Whereas the bias of rubber spring  1302  may tend to hold edge  1216 S in the second position when in contact with a horizontal surface  808 A as per  FIG. 9I , the same bias tends to push the edge  1216 S back down the sloped surface  808   a  to its first position due to the sufficient slope of sloped surface  808   a . Thus, the sloped surface  808   a , with sufficient slope, reduces or eliminates the ratcheting characteristic. In this embodiment, 22° is sufficient slope for the smooth sloped surface  808   a . Surface  808   a  may also provide better control of wedge pivot end during assembly. It is noted here that the sloped surface  808   a  is an option providing smooth travel for the edge  1216 S to the ledge  808   b . This configuration could be replaced with a flat surface  808   a  and a fence like barrier providing a threshold that edge  1216 S must surmount before the wedge  1202 S can attain uninhibited rotation to the permanent unlock condition. The sloped surface  808   a  is chosen for smooth translational movement of edge  1216 S and ease of molding. 
     In one embodiment, a portion of wall  901  may be removed or “cored out” from the surface of top wall  808 A to facilitate operation of the single-use tack retaining system as discussed above. It is not necessary to core out a portion of wall  901  in the reusable tack retaining system because the protrusions  1221 R and  1222 R residing in recesses  821  and  822  prevent wedge  1202 R from rotating into the cored out area. However, coring out of wall  901  to the extent shown in  FIG. 9E  and  FIGS. 14 through 31 , may assist in the molding process without substantially reducing the strength of the tag, so the cored out area of wall  901  is shown in views of both the single-use and reusable tack retaining systems henceforth. Another change seen in  FIG. 9E  is the improved position of walls  816  and  818  and walls  803 K and  803 L. Walls  816  and  818  are sloped to be parallel with the wedge surface  1205  when in the rest condition, providing for a virtually even surface for the entire surface  1304 A of the rubber spring to bear against. Additionally, referring to the reusable embodiment, walls  803 K and  803 L are extended vertically to intersect walls  816  and  818  respectively at their improved position. This may provide deeper recesses  821  and  822  to better contain protrusions  1221 R and  1222 R of the wedge. 
       FIG. 11  illustrates an interior view of a lower housing for a security tag in accordance with one embodiment. As previously described, lower housing  116  may have pocket  1110 . Pocket  1110  may provide bearing surface  1111 B for rubber spring  1302 , as described in more detail with reference to  FIG. 13 . The circular inside wall  1113  may guide and secure circular protrusion  809  of upper housing  114  when upper housing  114  and lower housing  116  are joined together to form security tag  100 . 
       FIG. 12A  illustrates a first view of a wedge for a security tag in accordance with one embodiment.  FIG. 12A  illustrates a wedge  1202 R suitable for use with a reusable tack retaining system. In one embodiment, for example, wedge  1202 R may be formed using magnetically attractable steel. Wedge  1202 R may have a shape that is approximately 0.240 inches by 0.240 inches by 0.032 inches thick. Protrusions  1221 R and  1222 R may assist wedge  1202 R for reuse. Protrusions  1221 R and  1222 R may each have the approximate dimensions of 0.032 inches by 0.032 inches by 0.032 inches. The embodiments are not limited in this context. 
     Wedge  1202 R may have alternate arrangements as well. For example, wedge pivot side  1207 R may be rounded from end to end including axle protrusions  1221 R and  1222 R, and the intersection of top wall  808 A and back wall  803 D may be rounded to movably fit the rounded pivot side  1207 R. This configuration may potentially provide a better bearing surface for rounded pivot side  1207 R, although at additional wedge manufacturing costs. The embodiments are not limited in this context. 
       FIG. 12B  illustrates a second view of a wedge for a security tag in accordance with one embodiment.  FIG. 12B  illustrates a wedge  1202 S suitable for use with a single-use tack retaining system. In one embodiment, for example, wedge  1202 S may be similar to wedge  1202 R. Wedge  1202 S may omit, however, axle protrusions  1221 R and  1222 R. Since wedge  1202 S does not have axle protrusions  1221 R and  1222 R, compartment  802  of security tag  100  does not need corresponding recesses  821  and  822  to hold axle protrusions  1221 R and  1222 R. The embodiments are not limited in this context. 
     In a single-use tack retaining system, for example, wedge  1202 S is not only attracted to the magnetic surface, but is also driven to a vertical stance by the magnetic force urging rotational movement around the expanding rubber spring  1302 . The magnetic attracting force field direction of the magnet, which is typically perpendicular to the pole surface in the center of the surface, drives the long dimension of wedge  1202 S into alignment with the direction of the magnetic attracting force field. The single-use tack retaining system may utilize wedge  1202 S and the magnetic rotational effect characteristic to attain a permanent unlock condition for security tag  100 . 
     Certain dimensions may be selected for one or more elements of a single-use tack retaining system in order to allow tack retaining edge  1213 S to be rotated from under groove lip  107  of tack shank  106  during detachment operations. At the same time, edge  1216 S should be thrust off edge  808   b  (see  FIGS. 25 and 26 ) of surface  808   a  and into the CO area of wall  808 A. The movement of edge  1216 S is rotational and also slightly down and lateral off of surface  808   a  and edge  808   b  and into CO. 
       FIG. 13  illustrates a view of a rubber spring for a security tag in accordance with one embodiment.  FIG. 13  illustrates a rubber spring  1302  suitable for use with a reusable security tag or single-use security tag. In one embodiment, rubber spring  1302  may approximate the shape of a rectangular block, having a width w, height h, and a depth t. Rubber spring  1302  may also be implemented using other shapes as desired for a given set of design constraints. One feature of the rubber spring is that it provides a bias that is resilient in all directions relatively uniformly similar to a rubber ball. This feature provides vertical and horizontal components of bias essential in the functioning of the tack retaining system. The embodiments are not limited in this context. 
     In one embodiment, rubber spring  1302  may be made from a material such as rubber or foam rubber. The rubber material may provide a certain amount of bias (or compression force) suitable for a given implementation. The amount of bias provided by rubber spring  1302  can be changed by the formulation of the rubber product used to make rubber spring  1302 . Consequently, the amount of magnetic strength needed for magnetic detaching device  602  may vary in accordance with the amount of bias provided by rubber spring  1302 . For example, if rubber spring  1302  is made of a rubber product having a lower firmness and therefore providing a lower bias, magnetic device  602  may be arranged to perform detachment operations using a lower magnetic strength. In another example, if rubber spring  1302  is made of a rubber product having a higher firmness and therefore providing a higher bias, magnetic device  602  may be arranged to perform detachment operations using a higher magnetic strength. The embodiments are not limited in this context. 
     In one embodiment, rubber spring  1302  may be implemented using a number of different rubber products. For example, the rubber material may comprise PORON Urethane Foam number 4701-40 Soft, or 4701-50 Firm, or 4701-60 Very Firm, all made by Rogers Corporation. In addition to the previously described characteristics, the specific rubber material selected for rubber spring  1302  should offer sufficient stability and durability desired for a given implementation of security tag  100 . The dimensions of rubber spring  1302  may also be important for proper detachment as well. The design flexibility offered by potentially modifying one or more characteristics of rubber spring  1302  may allow “scalability” of design for different detachment characteristics for different security tags  100 . The embodiments are not limited in this context. 
       FIG. 9E  shows the upper cover configuration used in  FIGS. 14-31 . The improved position of walls  816  and  818  and walls  803 K and  803 L are indicated for reference in reusable tag cross sections  FIGS. 14 through 19 .  FIG. 14  illustrates a first view of a cross-section taken along line D-D of a reusable security tag with a tack, wedge, and rubber spring in accordance with one embodiment.  FIG. 14  is a partial cross section D-D of  FIG. 1A  with the reusable tack retaining system showing tack shank  106  partially inserted into tack hole  807 . The reusable tack retaining system is in a rest condition, and the operations for attaching tack assembly  102  to security tag  100  have been initiated. Pointed end  112  is inserted into aperture  120  and into tack hole  807 . Pointed end  112  is approaching inclined surface  1209 R of wedge  1202 R. Axle protrusions  1221 R and  1222 R are constrained to their respective recesses  821  and  822 , but are allowed to rotate within recesses  821  and  822 . In one embodiment, wedge  1202 R may be biased with surface  1209 R on wedge stop  902  and edge  1216 R on sloped surface  808   a  by rubber spring  1302  at a wedge angle {acute over (Ø)} of approximately 22° when in the rest condition. Edge  1216 R is about 0.012 inches from back wall  808 D. 
       FIG. 15  illustrates a second view of a cross-section taken along line D-D of a reusable security tag with a tack, wedge, and rubber spring in accordance with one embodiment.  FIG. 15  shows tack shank  106  further inserted into tack hole  807  until pointed end  112  has contacted surface  1209 R. Such contact may force wedge  1202 R to begin rotating counterclockwise approximately about edge  1215 R, and edge  1216 R to slide slightly on surface  808   a . It is worthy to note that wedge  1202 R does not necessarily rotate exactly about contact point of edge  1215 R and back wall  803 D. There may be a small movement of the contact point on wall  808 D as wedge angle {acute over (Ø)} changes. The movement on back wall  803 D may approximate 0.002 inches in total as wedge angle {acute over (Ø)} changes from 22° to 40°. This movement may slightly effect the initial tack clearance. Pointed end  112  may slide across surface  1209 R such that it is contacting tack retaining edge  1213 R. Rubber spring  1302  may compress slightly more between wedge  1202 R and surface  1111 B. The reusable tack retaining system does not necessarily enter a locked condition since tack assembly  102  could still be retracted from security tag  100 . 
       FIG. 16  illustrates a third view of a cross-section taken along line D-D of a reusable security tag with a tack, wedge, and rubber spring in accordance with one embodiment.  FIG. 16  shows tack shank  106  when inserted further into tack hole  807  until tack shank  106  makes contact with and begins to slide by tack retaining edge  1213 R. Wedge angle {acute over (Ø)} is approximately 40°. Further insertion of tack shank  106  may position tack retaining edge  1213 R adjacent to a first of grooves  108 . While tack retaining edge  1213 R is in contact with tack shank  106 , there is no further counterclockwise rotation of wedge  1202 R. The reusable tack retaining system may not yet enter a locked condition since tack assembly  102  could still be retracted from security tag  100 . 
       FIG. 17  illustrates a fourth view of a cross-section taken along line D-D of a reusable security tag with a tack, wedge, and rubber spring in accordance with one embodiment.  FIG. 17  shows tack shank  106  inserted further into tack hole  807  until tack groove  108  is adjacent to tack retaining edge  1213 R. At this point, the bias of rubber spring  1302  between wedge  1202 R and walls  1111 B and  808 D may force tack retaining edge  1213 R into tack groove  108  via a clockwise rotation of wedge  1202 R. Wedge angle {acute over (Ø)} is approximately 39.6°, and edge  1216 R is approximately 0.019 inches from back wall  808 D. Attempts to retract tack assembly  102  from security tag  100  are now prevented by the wedge as previously described. Tack retaining edge  1213 R pointed tip end is now biased into the intersection of groove lip  107  of tack groove  108  by rubber spring  1302 , thus restraining the tack  102  from being extracted from the tag  100 . At this point the reusable tack retaining system is in a locked condition. 
     In one embodiment, tack assembly  102  may be removed or detached from security tag  100  implemented with a reusable tack retaining system through the use of magnetic detaching device  602 . In order to detach tack assembly  102  from security tag  100 , security tag  100  should be seated or nearly seated in magnetic detaching device  602 . The affects of magnetic detaching device  602  on the reusable tack retaining system to detach tack assembly  102  from security tag  100  may be described in more detail with reference to  FIGS. 18 and 19 . 
       FIG. 18  illustrates a first view of a cross-section taken along line D-D of a reusable security tag with a tack, wedge, rubber spring, and a magnetic detaching device in accordance with one embodiment.  FIG. 18  shows the same partial cross section of  FIG. 17  but as seated in magnetic detaching device  602 . Further, assume sufficient Fp has been applied to hold the position of wedge  1202 R in the locked condition when tag  100  is placed in magnetic detacher  602 . When Fp is removed, magnetic detaching device  602  should be strong enough to attract wedge  1202 R against the bias of rubber spring  1302 , causing wedge  1202 R to rotate counterclockwise about edge  1215 R and axle protrusions  1221 R and  1222 R which are contained in their respective recesses  821  and  822 , such that tack retaining edge  1213 R is rotated sufficiently to clear groove lip  107  of tack shank  106 . 
     The condition shown in  FIG. 18  may occur without necessarily applying Fp to hold the locked condition since sufficient Fp may already be applied by garment  202  when secured between tack head  104  and security tag  100 . In some cases, when security tag  100  is in magnetic detaching device  602 , an insertion force Fi may be applied to tack head  104  to move tack shank  106  into security tag  100  sufficiently to allow groove lip  107  to release tack retaining edge  1213 R so that detaching operations can be performed. Typically, movement needed for tack shank  106  may approximate 0.004 inches. This type of push-in operation to assist detachment typically exists to some extent for all magnetic clutches. In the vast majority of detachments, however, merely placing security tag  100  in magnetic detaching device  602  will be sufficient to free tack assembly  102  from security tag  100  for detachment operations to be completed. 
       FIG. 19  illustrates a second view of a cross-section taken along line D-D of a reusable security tag with a tack, wedge, rubber spring, and a magnetic detaching device in accordance with one embodiment.  FIG. 19  shows the unlock condition after Fp is removed. Groove lip  107  is released from tack retaining edge  1213 R and thus tack assembly  102  can be retracted from security tag  100  as long as security tag  100  remains in magnetic detaching device  602 . When tack assembly  102  is retracted and security tag  100  is removed from magnetic detaching device  602 , the condition of wedge  1202 R reverts to the rest condition shown in  FIG. 14 . If tack shank  106  is left in tack hole  807  when security tag  100  is removed from magnetic detaching device  602 , the condition of wedge  1202 R may revert to that shown in  FIG. 17 . This operation may be counter productive however, since the purpose is to detach tack assembly  102  from security tag  100 . 
       FIG. 20  illustrates a first view of a cross-section taken along line D-D of a single-use security tag with a tack, wedge, and rubber spring in accordance with one embodiment.  FIG. 20  is a partial cross section D-D of  FIG. 1A  with a single-use tack retaining system showing tack shank  106  partially inserted into tack hole  807 . As shown in  FIG. 20 , the single-use tack retaining system is in a rest condition, and attachment operations to attach tack assembly  102  to security tag  100  have been initiated. Pointed end  112  may be inserted into aperture  120  and tack hole  807 . Pointed end  112  may be approaching inclined surface  1209 S of wedge  1202 S. Wedge  1202 S may be biased against wedge stop  902  and sloped surface  808   a  by rubber spring  1302 . In a rest condition, wedge  1202 S may be biased with surface  1209 S on wedge stop  902  (not fully shown) and edge  1216 S on sloped surface  808   a  by rubber spring  1302  at a wedge angle {acute over (Ø)} of approximately 22° when in rest condition. Edge  1216 S is approximately 0.012 inches from back wall  808 D and approximately 0.020 inches from ledge  808   b.    
       FIG. 21  illustrates a second view of a cross-section taken along line D-D of a single-use security tag with a tack, wedge, and rubber spring in accordance with one embodiment.  FIG. 21  shows tack shank  106  further inserted into tack hole  807  and where pointed end  112  has contacted surface  1209 S. The contact may force wedge  1202 S to begin rotating counterclockwise approximately about edge  1215 S, and edge  1216 S to slide slightly to the left on surface  808   a . It is worthy to note that wedge  1202 S does not necessarily rotate exactly about the rest condition contact point of edge  1215 S and back wall  803 D. There may be a small movement of the contact point as angle {acute over (Ø)} changes. The movement on back wall  803 D may comprise, for example, 0.002 inches in total when the wedge angle moves from 22° to 40°. The movement may slightly effect the initial additional tack clearance. Pointed end  112  may slide across surface  1209 S such that it makes contact with tack retaining edge  1213 S. Rubber spring  1302  may compress slightly more between wedge  1202 S and surface  1111 B. The single-use tack retaining system may not yet enter into a locked condition since tack assembly  102  could still be retracted from security tag  100 . 
       FIG. 22  illustrates a third view of a cross-section taken along line D-D of a single-use security tag with a tack, wedge, and rubber spring in accordance with one embodiment.  FIG. 22  shows tack shank  106  inserted further into tack hole  807  until tack shank  106  makes contact with, and begins to slide by, tack retaining edge  1213 S. Further insertion of tack shank  106  may cause tack retaining edge  1213 S to become adjacent to a first tack groove  108 . While tack retaining edge  1213 S is in contact with tack shank  106 , there may be no further counterclockwise rotation of wedge  1202 S. The wedge angle {acute over (Ø)} is approximately 40°. The single-use tack retaining system may not yet be in a locked condition since tack assembly  102  could still be retracted from security tag  100 . 
       FIG. 23  illustrates a fourth view of a cross-section taken along line D-D of a single-use security tag with a tack, wedge, and rubber spring in accordance with one embodiment.  FIG. 23  shows tack shank  106  inserted further into tack hole  807  until tack groove  108  is adjacent to tack retaining edge  1213 S. At this point, the bias of rubber spring  1302  between wedge  1202 S and walls  1111 B and  808 D may force tack retaining edge  1213 S into tack groove  108  via a clockwise rotation of wedge  1202 S. Wedge angle {acute over (Ø)} is approximately 39.6°. Edge  1216 S is approximately 0.019 inches from back wall  808 D and approximately 0.013 inches from ledge  808   b . Attempts to retract tack assembly  102  from security tag  100  are now prevented by wedge  1202 S as previously described. Tack retaining edge  1213 S pointed tip end is now biased into the intersection of groove lip  107  and tack groove  108  thus restraining the tack  102  from being extracted from the tag  100 . The single-use tack retaining system is now in a locked condition. 
     In one embodiment, tack assembly  102  may be removed or detached from security tag  100  as implemented with a single-use tack retaining system through use of magnetic detaching device  602 . In order to detach tack assembly  102  from security tag  100 , security tag  100  should be seated or nearly seated in magnetic detaching device  602 . The affects of magnetic detaching device  602  on the single-use tack retaining system to detach tack assembly  102  from security tag  100  may be described in more detail with reference to  FIGS. 24-30 . 
       FIG. 24  illustrates a first view of a cross-section taken along line D-D of a single-use security tag with a tack, wedge, rubber spring, and a magnetic detaching device in accordance with one embodiment.  FIG. 24  shows the same partial cross section of  FIG. 23  but as seated in magnetic detaching device  602 . Further, assume sufficient Fp has been applied to hold the position of wedge  1202 S in the locked condition when tag  100  is placed in magnetic detacher  602 . When Fp is removed, detachment begins. Magnetic detaching device  602  begins to attract wedge  1202 S against the bias of rubber spring  1302 , thereby urging wedge  1202 S to rotate counterclockwise approximately about edge  1215 S, and urging translation of edge  1216 S to the left on sloped surface  808   a  towards ledge  808   b.    
     The condition shown in  FIG. 24  may occur without applying Fp to hold the locked condition because sufficient Fp may already be applied by garment  202  when secured between tack head  104  and security tag  100 . In some cases, when security tag  100  is placed within magnetic detaching device  602 , an insertion force Fi may be applied to tack head  104  to move tack shank  106  into security tag  100  with sufficient depth to allow groove lip  107  to release tack retaining edge  1213 S so that detaching can occur. In some cases, for example, tack shank  106  may need to be pushed or moved approximately 0.004 inches to release tack retaining edge  1213 S. The occasional use of addition insertion force Fi to assist detachment typically exists to some extent for all magnetic clutches. In the vast majority of detachments, however, merely placing security tag  100  in magnetic detaching device  602  will be sufficient to cause the single-use tack retaining system to attain a permanent unlock condition. 
       FIG. 25  illustrates a second view of a cross-section taken along line D-D of a single-use security tag with a tack, wedge, rubber spring, and a magnetic detaching device in accordance with one embodiment.  FIG. 25  shows the effect of an attractive force from magnetic assembly  603  on wedge  1202 S. The magnetic attractive force may cause wedge  1202 S to compress rubber spring  1302  slightly more than shown in  FIG. 24 , and tack retaining edge  1213 S may be rotated slightly out from under groove lip  107  and drawn slightly toward magnetic assembly pole surface  604 . Virtually at the same instant, edge  1216 S may move across surface  808   a  to ledge  808   b . It is worthy to note that with the reusable tack retaining system, the lateral movement of wedge edge  1216 R across surface  808   a  is prevented since axle protrusions  1221 R and  1222 R are restricted from lateral movement by their respective recesses  821  and  822 . 
       FIG. 26  illustrates a third view of a cross-section taken along line D-D of a single-use security tag with a tack, wedge, rubber spring, and a magnetic detaching device in accordance with one embodiment.  FIG. 26  shows tack retaining edge  1213 S of wedge  1202 S being attracted toward magnetic assembly surface  604  while edge  1216 S clears ledge  808   b . In addition, rubber spring  1302  may begin to expand from the compressed condition shown in  FIG. 25 , which may push edge  1216 S toward tack assembly  102 . 
       FIG. 27  illustrates a fourth view of a cross-section taken along line D-D of a single-use security tag with a tack, wedge, rubber spring, and a magnetic detaching device in accordance with one embodiment.  FIG. 27  shows edge  1213 S of wedge  1202 S being attracted further toward magnetic assembly surface  604 , while edge  1215 S clears ledge  808   b . Further, rubber spring  1302  may continue to expand further from the compressed condition shown in  FIG. 26 , which may push edge  1216 S further toward tack assembly  102 . 
       FIG. 28  illustrates a fifth view of a cross-section taken along line D-D of a single-use security tag with a tack, wedge, rubber spring, and a magnetic detaching device in accordance with one embodiment.  FIG. 28  shows rubber spring  1302  in an expanded position which may help drive wedge  1202 S to a substantially vertical position, while magnetic assembly  603  continues to attract tack retaining edge  1213 S toward magnetic assembly surface  604 , and drive wedge  1202 S to a vertical position. 
       FIG. 29  illustrates a sixth view of a cross-section taken along line D-D of a single-use security tag with a tack, wedge, rubber spring, and a magnetic detaching device in accordance with one embodiment.  FIG. 29  shows wedge  1202 S in a substantially vertical position beside a fully expanded rubber spring  1302 . Tack retaining edge  1213 S is as close to pole surface  604  as possible, and is in contact with surface  1111 B. Tack assembly  102  is completely free from impediment and can be retracted from security tag  100 . Security tag  100  is now in a permanent unlock condition. 
       FIG. 30  illustrates a seventh view of a cross-section taken along line D-D of a single-use security tag with a tack, wedge, and rubber spring, in accordance with one embodiment.  FIG. 30  shows the same permanent unlock condition may exist when security tag  100  is removed from magnetic detaching device  602 . Tack assembly  102  may be retracted before or after security tag  100  is removed from magnetic detaching device  602 . In the configuration shown in  FIG. 29  and  FIG. 30 , wedge  1202 S cannot be restored to the rest condition of  FIG. 20  for reuse without disassembling and rebuilding the security tag  100 . 
       FIG. 31  illustrates an interior view of an upper housing for a single-use security tag in accordance with one embodiment.  FIG. 31  shows one possible configuration of the single-use tack retaining system compartment  802  to reduce or eliminate the effects of slamming. The identifiers of  FIG. 31  are similar to those used for  FIG. 9G  for comparison purposes. It is worthy to note that the walls controlling the location of rubber spring  1302  have been moved so that rubber spring  1302  is essentially centered over the center of gravity of wedge  1202 S. This configuration of wedge compartment  802  virtually eliminates the effects of slamming as defined earlier. 
     The embodiment of  FIG. 8D  yielded the Fp-ATC curve C in  FIG. 10 . The embodiment of  FIG. 8D , although it has practical functionality when Fp values do not exceed about 20 pounds, values of Fp above 20 pounds create undesirable characteristics. Improvements to overcome these undesirable characteristics were made resulting in the tack retaining system embodiment of  FIG. 9F . The outside appearance and basic functionality of the security tag  100  and the tack  102  did not change, but improvements have been introduced involving both the reusable version and the single-use version of the security tag  100 . These improvements primarily involved means of increasing the Fpo and reducing the additional tack clearance for each value of Fp, but special attention was given to preventing defeat of the single-use version by “slamming” or “ratcheting”. 
     Several “pull” tests were performed to verify that the changes made to the first tack retaining system embodiment of  FIG. 8D  resulting in the tack retaining system embodiment of  FIG. 9F  did indeed provide the improvements desired. All six pull tests and associated curve discussions that follow reflect on the improved tack retaining system embodiment depicted in  FIGS. 9E ,  9 F, and  9 G. Each pull was made on a Chatillon Model USTM machine at a pull rate of 3 inches per minute. Each of pull tests  1 - 6  involved pulls on four identical tags and tacks, with a first Fp pull to 15 pounds, a second Fp pull to 50 pounds, a third Fp pull to 100 pounds, and a fourth Fp pull to Fpo. Pull test  5  added two additional pulls; a fifth identical tag for a pull to an Fp of 25 pounds, and a sixth identical tag for a pull to an Fp of 120 pounds. Pull test  6  added two additional pulls as well; a fifth identical tag for a pull to an Fp of 25 pounds, and a sixth identical tag for a pull to an Fp of 140 pounds. The tag housings were made of ABS plastic or of polycarbonate plastic as discussed below. All resulting curves are shown in  FIG. 10 . All pull tests revealed that undesirable characteristics number (4), (5), and (6) were completely overcome by their respective remedies. Improvements to undesirable characteristics (1) and (2) are shown directly in the curves of  FIG. 10 , and an improvement to (3) is discussed for each pull test. The permanent ATC values are also discussed. 
     The result of pull test  1  is reflected in curve D. Curve D is typical for a single-use tack retaining system embodiment having an ABS plastic housing, a wedge hardness of RC 47, a tack hardness of RC 40. The Fp=15 lbs pull yielded a permanent ATC of 0.007 inches and a Fi of “0” pounds required to attain the free condition. The Fp=50 lbs pull yielded a permanent ATC of 0.025 inches and an Fi of 2 pounds required to attain the free condition. The Fp=100 lbs pull yielded a permanent ATC of 0.038 inches and an Fi of 5 pounds required to attain the free condition. The fourth pull yielded an Fpo of 110 pounds at an ATC of 0.097 inches. 
     The result of pull test  2  is reflected in curve E. Pull test  2  is essentially a repeat of pull test  1  except that a reusable wedge is used. The only significant difference is that the Fpo is 120 pounds. The extra 10 pounds can be attributed to the larger bearing surface against wall  808 D that the reusable wedge has. The ATC at Fpo increased from 0.097 to 0.102 inches. 
     The result of pull test  3  is reflected in curve F. Pull test  3  is essentially a repeat of pull test  1  except that the housing material is the firmer polycarbonate plastic. Note the major difference is that the Fpo increased from 110 pounds to 130 pounds, and ATC increased from 0.097 to 0.104 inches. The permanent ATC improved about 20% at each Fp value, and Fi was about the same at each Fp value. 
     The result of pull test  4  is reflected in curve G. Pull test  4  is essentially a repeat of pull test  3  except that a reusable wedge is used. Note the major difference is that the Fpo increased from 130 pounds to 140 pounds, and ATC at Fpo increased from 0.104 to 0.107 inches. 
     The result of pull test  5  is reflected in curve H. Pull test  5  is essentially a repeat of pull test  1  except that the wedge hardness is approximately RC 42 and the tack hardness is approximately RC 48. An improvement in Fpo from 110 to 125 pounds was accomplished, and a reduction in ATC at Fpo from 0.097 to 0.082 inches was accomplished. The Fp=15 lbs pull yielded a permanent ATC of 0.008 inches and a Fi of “0” pounds required to attain the free condition. The Fp=25 lbs pull yielded a permanent ATC of 0.012 inches and an Fi of 0.4 pounds required to attain the free condition. The Fp=50 lbs pull yielded a permanent ATC of 0.020 inches and an Fi of 2 pounds required to attain the free condition. The Fp=100 lbs pull yielded a permanent ATC of 0.029 inches and an Fi of 5 pounds required to attain the free condition. The Fp=120 lbs pull yielded a permanent ATC of 0.034 inches and an Fi of 6 pounds required to attain the free condition. The sixth pull yielded an Fpo of 125 pounds at an ATC of 0.082 inches. 
     The result of pull test  6  is reflected in curve I. Pull test  6  is essentially a repeat of pull test  5  except that the housing material is the firmer polycarbonate plastic. An improvement in Fpo from 125 to 145 pounds was accomplished. The ATC at Fpo remained the same. The Fp=15 lbs pull yielded a permanent ATC of 0.004 inches and a Fi of “0” pounds required to attain the free condition. The Fp=25 lbs pull yielded a permanent ATC of 0.007 inches and a Fi of 0.5 pounds required to attain the free condition. The Fp=50 lbs pull yielded a permanent ATC of 0.012 inches and a Fi of 2 pounds required to attain the free condition. The Fp=100 lbs pull yielded a permanent ATC of 0.025 inches and a Fi of 5 pounds required to attain the free condition. The Fp=140 lbs pull yielded a permanent ATC of 0.026 inches and a Fi of 7 pounds required to attain the free condition. The sixth pull yielded an Fpo of 145 pounds at an ATC of 0.082 inches. 
     The pull test  6  results reflect all improvements to overcome the undesirable characteristics. Fpo is well above 125 pounds, the curve I is between curve A and curve B, and Fi requirements greatly improved. For example, for an Fp of 20 pounds the Fi reduced from 7 to less than 0.5 pounds, for an Fp of 50 pounds the Fi reduced from 15 to 2 pounds, for an Fp of 65 pounds the Fi required reduced from 35 to approximately 3 pounds. In summary, major enhancements in the curve C were made by the wedge stop, higher wedge angle when in locked condition, the firmer material, and the tack being harder than the wedge as described. Operational enhancements not seen on the curves included the following: (1) Fi improvement is primarily attributed to the wedge stop; (2) permanent ATC improved primarily due to using the firmer housing material, (3) ratcheting was reduced or eliminated by incorporating the sloped surface  808   a , edge  808   b , and the cored out area; (4) slamming was reduced or eliminated by relocating the rubber spring per  FIG. 31 ; (5) after any strength of pull up to Fpo the tack will always re-catch the wedge, primarily due to the wedge stop; and (6) over-rotation reduced or eliminated by the wedge stop. 
     From these 6 pull tests performed, a reusable configuration suitable for a production environment may be derived. In one embodiment, for example, the following configuration and values may be used: (1) housing formed of polycarbonate plastic; (2) hardness of tack shank  106  is RC 47-50; (3) tack groove  108  and groove lip  107  should have a depth of 0.003 to 0.004 inches, groove length should be 0.040 inches minimum, and spacing should be approximately 0.040 inches; (4) wedge dimensions should be 0.235 inches to 0.240 inches wide, by 0.032 inches+/−0.001 inches thick, with axle protrusions  1221 R and  1222 R each being approximately 0.032 inch cubes (as illustrated in  FIG. 12A ), the angle of sharp edge  1220  should be 30°+/−1 degree and 0.236 inches to 0.242 inches long, and wedge  1202 R should have a hardness of RC 40 to RC 43. The embodiments are not limited in this context. 
     Using the above configuration, the embodiment may have an Fp versus additional tack clearance curve (depicted as curve I in  FIG. 10 ) that is almost linear for Fp from 0 to 145 pounds, additional tack clearance of approximately 0.080 inches at Fpo, and a rate of approximately 1800 pounds/inch. The limits for the rate and pullout value have, to the first order, been reached. Further tests have shown that using the above configuration, changing only to a tack hardness of RC50 to RC52 and a measured wedge hardness of RC45, the Fpo is typically 170 lbs at an ATC of typically 0.090 inches; and the same test using ABS plastic for the housing yields a typical Fpo of 150 lbs at an ATC of typically 0.090 inches. 
     Other improvements are also possible, but may have higher corresponding costs to consider. For example, although a firmer plastic such as polycarbonate might be used to reduce the plastic yield, the higher cost may not be justified because the slightly less Fpo (and slightly more additional tack clearance) of the softer and less expensive ABS plastic might be acceptable. An Fpo of approximately 125 pounds at an additional tack clearance of about 0.070 inches at an Fp of 100 pounds that is attainable using ABS plastic is better than most conventional reusable security tags. In another example, surface  1207 R of wedge  1202 R might be rounded to fit loosely into a rounded corner of intersection  803 D and  808 A. This may result in an increased Fpo by approximately 5 pounds, although the incremental increase may not justify the additional cost to round surface  1207 R. The embodiments are not limited in this context. 
       FIG. 32  illustrates a perspective view of a security tag  2100 , a tack assembly  2102 , and an article  202  in an unfastened position, in accordance with one embodiment.  FIG. 33  illustrates a perspective view of the tack assembly  2102  and a disassembled security tag  2100 , in accordance with one embodiment. 
     Tack assembly  2102  in  FIG. 32-33  (as well as one or more of  FIGS. 42-44  and  46 - 55 ) may have portions corresponding to those of one or more of the embodiments of tack assembly  102 , respectively, as described above with respect to  FIGS. 1-31 . For example, tack assembly  2102  may include one or more elements  2104 ,  2106 ,  2107 ,  2108 ,  2109 , and  2112  that respectively correspond, in various embodiments, to  104 ,  106 ,  107 ,  108 ,  109 , and  112  of tack assembly  102 , though the design may be altered for one or more elements. 
     Security tag  2100  may include a housing  2113 , tack retaining system, and sensor. We first refer to the sensor, as shown in the embodiment of  FIG. 33 . The sensor may include one or more linear amorphous resonators  2402 A and a magnetized bias  2402 B in one embodiment, may be enclosed and secured within the housing  2113 . A spacer  2403  may separate the one or more linear amorphous resonators  2402 A and magnetized bias  2402 B. In other embodiments, the sensor may be another type of sensor, such as any of the embodiments of sensor  402  described above, an RF, RFID, electromagnetic, ferrite assembly, or any combination of two or more of the aforementioned and any other electronic article surveillance (EAS) or other sensors. 
     Security tag  2100  in  FIGS. 32-33  (as well as portions thereof shown in  FIGS. 34-48 ) may also include different embodiments of elements of security tag  100 , described above with respect to  FIGS. 1-31 . For example, in various embodiments, security tag  2100  may include a housing  2113  that includes upper and lower housings  2114  and  2116 , respectively, which may have one or more elements  2118 ,  2120 ,  2122 ,  2124 ,  2126 ,  2130 ,  2132 ,  2134 ,  2136 ,  2138 ,  2504 ,  2508 ,  2802 ,  2807 ,  2808   a ,  2808 A,  2809 ,  2814 ,  3110 ,  3111 B,  3113 , and  3115  that respectively correspond to elements  118 ,  120 ,  122 ,  124 ,  126 ,  130 ,  132 ,  134 ,  136 ,  138 ,  504 ,  508 ,  802 ,  807 ,  808   a ,  808 A,  809 ,  814 ,  1110 ,  1111 B,  1113 , and  1115  of upper and lower housings  114  and  116  of security tag  100 . 
     Additionally, line  2412  and cross section D-D in  FIGS. 32-33  may correspond to line  412  and cross section D-D shown in, e.g., FIGS.  1  and  4 - 5 , and described above. 
     Housing  2113  may include a wedge compartment  2802  delineated by walls  2803 . The walls  2803  may be shaped such that the wedge compartment  2802  may receive the tack retaining system or a portion thereof. For example, in one embodiment, walls  2803  include one or more elements  2803 C- 2803 D,  2803 F- 2803 I, and  2803 K- 2803 L, such as shown in  FIG. 34  described below, which may respectively correspond to elements  803 C- 803 D,  803 F- 803 I, and  803 K- 803 L of walls  803  of wedge compartment  802  of security tag  100  described herein. 
       FIG. 34  illustrates an interior view of part of upper housing  2114  of a security tag  2100 , in accordance with one embodiment. In this embodiment, walls  2803  may be shaped such that the wedge compartment  2802  may receive either reusable wedge  3202 R or a single use wedge embodiment (which may be similar to wedge  3202 R, with or without protrusions  3221 R or  3222 R) and may also receive either biasing member  3302  or  4302 . Embodiments of wedge  3202 R, the single use wedge, and biasing members  3302 ,  4302  are described below. 
     For example, in one embodiment, back wall  2803 D may be contoured with back wall portions  2804 A and  2804 B that delineate recesses shaped similar to portions of biasing member  4302 , such as described with respect to the embodiment of  FIG. 38  below. In this embodiment, the back wall portions  2804 A and  2804 B may be concave and thus delineate convex recesses shaped similar to locating elements  4335 A- 4335 B of biasing member  4302 . Such an arrangement may facilitate positioning and/or securing of biasing member  4302  within wedge compartment  2802 . 
     Walls  2803 K and  2803 L may at least partially delineate recesses  2821  and  2822 , respectively. These elements  2803 K,  2803 L,  2821 , and  2822  may respectively correspond to  803 K,  803 L,  821 , and  822  of security tag  100  described herein. Thus, for example, in a reusable embodiment of security tag  2100 , wedge  3202 R (described below with respect to  FIG. 36 ) of the tack retaining system includes protrusions  3221 R and  3222 R that may be at least partially disposed and may rotate, translate, move in a combination of rotation and translation, and/or otherwise move within recesses  2822  and  2821 , respectively. 
       FIG. 35  illustrates an interior view of part of lower housing  2116  of a security tag  2100 , in accordance with one embodiment. As described with respect to the lower housing  116  of security tag  100  of  FIGS. 1-31  for a biasing member that is a spring  1302 , lower housing  2116  may have a corresponding pocket  3110  providing a bearing surface  3111 B for a biasing member, such as biasing member  3302  or  4302  described in  FIG. 37  or  38 , respectively. Also, circular side wall  3113  may guide and secure circular protrusion  2809  of upper housing  2114  when upper housing  2114  and lower housing  2116  are joined together when assembling security tag  2100 . Bearing surface  3111 B may, in one embodiment, provide at least some of the force that restricts movement of either biasing member  3302  or  4302  out of position in a vertical direction, out of wedge compartment  2802 , when a force is applied by wedge  3202 R or another wedge, such as described herein. Lower housing  2116  may also include a bearing protrusion  3114  that may restrict movement of the biasing member  3302  or  4302  out of position in a lateral direction, across and within wedge compartment  2802 , in response to the force applied to wedge  3202 R or another wedge. 
     For example, bearing surface  3111 B and possibly also a bearing protrusion  3114  may restrict movement of body  3304 , but not leaf spring  3350 , of biasing member  3302 , which is shown in and described below with respect to  FIG. 37 . Where wedge  3202 R is forced into rotation and/or other movement by force with tack shank  2106  such that security tag  2100  is in the locked condition, the resultant torque and other forces applied by wedge  3202 R to leaf spring  3350  may rotate, deflect, bend, move with some combination of the three aforementioned movements, and/or otherwise move leaf spring  3350 , which may apply like opposing forces onto wedge  3202 R. However, the body  3304  may be restricted to little or negligible movement because the bearing surface  3111 B and bearing protrusion  3114  (along with other surfaces corresponding to those described with respect to security tag  100 ) may offset those wedge  3202 R forces with normal and friction forces, etc. 
     The tack retaining system of security tag  2100  may include a wedge, such as wedge  3202 R or a single-use wedge (such as  3202 R with or without protrusions  3221 R and  3222 R, as described below), and a biasing member, such as any embodiment of biasing member  1302  described above or biasing member  3302  or  4302  described below. 
       FIG. 36  illustrates a perspective view of a wedge  3202 R of a tack retaining system for a security tag  2100 , in accordance with one embodiment. Wedge  3202 R may be for a reusable tack retaining system and thus a reusable security tag  2100 , such as described above with respect to the tack retaining system embodiments of security tag  100  including wedge  1202 R. Wedge  3202 R may be magnetically attractable, such as described with respect to wedge  1202  herein and/or such that wedge  3202 R comprises or is formed of a magnetic material such as iron, nickel, or cobalt, or an alloy of iron, nickel, or cobalt. For example, in one embodiment, wedge  3202 R includes steel, such as hardened carbon steel. In another embodiment, wedge  3202 R includes one or more magnetic materials and also one or more nonmagnetic materials. 
     In various embodiments, elements  3203 R,  3205 R,  3207 R,  3209 R,  3211 R,  3214 R,  3215 R,  3216 R,  3217 R,  3221 R, and  3222 R of wedge  3202 R may respectively correspond to  1203 R,  1205 R,  1207 R,  1209 R,  1211 R,  1214 R,  1215 R,  1216 R,  1217 R,  1221 R, and  1222 R of wedge  1202 R. 
     However, in one embodiment, wedge sides  3211 R and  3214 R may taper toward the tack retaining portion, which may include one or more edges (along with the surfaces forming the edges) of wedge  3202 R that engage a tack lip  2107  and possibly another surface of tack groove  2108  of tack  2102  when the security tag  2100  is in the locked condition. As an example of such tapering, wedge sides  3211 R and  3214 R may respectively include substantially planar portions  3211 AR and  3214 AR, which may be parallel or close to parallel to each other, and also substantially planar portions  3211 BR and  3214 BR, which each may taper toward the tack retaining portion. In other embodiments, the wedge sides  3211 R and  3214 R may be substantially parallel, such as sides  1211 R and  1214 R of wedge  1202 R shown in  FIG. 12A  above, or may be otherwise shaped. 
     In another embodiment, inclined surface  3209 R of wedge  3202 R may not form an edge with wedge surface  3205 R (unlike tack retaining edge  1213 R formed by the intersection of inclined surface  1209 R and wedge surface  1205 R in the wedge  1202 R embodiment shown in  FIG. 12A ). Instead, wedge  3202 R may include inclined surface  3223 R, which may extend from wedge surface  3205 R to or near the edge  3213 R of inclined surface  3209 R. 
     For example, in one embodiment, inclined surface  3223 R extends between wedge surface  3205 R and edge  3226 R. Front side  3228 R may extend between edges  3213 R and  3226 R, and may be perpendicular or close to perpendicular to one or more of wedge surfaces  3203 R,  3205 R,  3211 AR, and  3214 AR, and/or may be parallel or close to parallel to  3207 R. Surface  3209 R may form a first chamfer on the tack retaining portion, surface  3223 R may form a second chamfer, and the front side  3228 R of the tack retaining portion may extend between these chamfers and be bounded by tack retaining edges  3213 R and  3226 R. This tack retaining portion with two chamfers may at least partially extend into a groove  2108  of tack shank  2106  of tack assembly  2102  when the security tag  2100  and tack assembly  2102  are in the “locked condition,” such as shown in the embodiment of  FIG. 43 . In the locked condition, the tack retaining portion having two chamfers may be adjacent the lip  2107  of that groove  2108 . For example, in one embodiment, edge  3213 R of the tack retaining portion abuts that lip  2107 . In that embodiment, edge  3226 R may abut the groove  2108  surface extending between the lips  2107  and  2109  of the groove  2108 . 
     In another embodiment, the two chamfers meet at an edge, and thus chamfered wedge surfaces  3209 R and  3223 R intersect such that edges  3213 R and  3226 R are coincident and the tack retaining portion is triangular in cross section. In such case, the coincidentally formed edge may be positioned adjacent a lip  2107  of a tack groove  2108  in the locked condition, such as described with respect to the tack retaining edge  1213 R of  FIG. 12A . 
     In another embodiment, edges  3213 R and  3226 R may be rounded off such that wedge surfaces  3209 R,  3223 R, and  3228 R together form a curved tack retaining portion. 
     In one embodiment, wedge  3202 R, including wedge surfaces  3209 R and  3223 R, are configured such that wedge  3202 R is substantially symmetrical about a plane parallel to, and equidistant from, wedge surfaces  3203 R and  3205 R, and also about a plane parallel to, and equidistant from, wedge surface portions  3211 AR and  3214 AR. This wedge  3202 R embodiment is referred to herein as a “symmetrical wedge.” In various embodiments, this symmetry may apply to a wedge  3202 R having any of the three aforementioned tack retaining portions (chamfered, triangular, curved) or any configuration of a tack retaining portion that may preserve the symmetry, such as any symmetrical tapering of surfaces  3203 R/ 3205 R and  3209 R/ 3223 R. For example, in an embodiment,  3209 R and  3223 R are not included, and  3203 R and  3205 R taper to front side  3228 R or to a coincident edge. 
     In another embodiment, wedge  3202 R includes only one chamfer, surface  3223 R. In this embodiment, the front side  3228 R of the tack retaining portion extends to surface  3203 R such that the wedge  3202 R does not have surface  3209 R, and the single tack retaining edge  3213 R may be formed by surfaces  3228 R and  3203 R. 
     In another embodiment, wedge  3202 R has two tack retaining edges  3213 R and  3226 R formed in part by surfaces  3209 R and  3223 R, one or both surfaces of which are not chamfers, but instead are curved surfaces, such as, for example, convex, concave, a combination of convex and concave, or include any other curves forming at least part of the surfaces. Front side  3228 R may be flat or any type of curve as well, in this and any of the aforementioned embodiments. In another embodiment, wedge  3202 R has one tack retaining edge  3213 R formed by surfaces  3228 R and  3203 R, one or both surfaces of which are curved surfaces. 
     In various embodiments, a tack retaining system for single use may include a wedge for single use, such as described above with respect to the tack retaining system embodiments including wedge  1202 S, or may include  3202 R. The single use wedge may include a wedge embodiment  3202 R described above, with or without protrusions  3221 R or  3222 R. In an embodiment in which the single use wedge is wedge  3202 R with protrusions  3221 R and  3222 R (and thus wedge  3202 R), a biasing member used in the tack retaining system of security tag  2100  may not include locating elements or other elements that may restrict movement of protrusions  3221 R and  3222 R out of their respective recesses  2822  and  2821  in upper housing  2114  of security tag  2100 . 
     Thus, for example, in a security tag  2100  including biasing member  3302 , shown in  FIG. 37  described below, biasing member  3302  may not have locating elements  3336 A- 3336 B in one embodiment, or, as shown in the embodiments of  FIGS. 46-48  described below, for example, these elements may be shaped and/or positioned to not restrict movement of protrusions  3221 R and  3222 R of wedge  3202 R out of their respective recesses  2822  and  2821 . In a security tag  2100  including biasing member  4302 , shown in  FIG. 38  described below, biasing member  4302  may correspondingly exclude or reconfigure its locating elements  4336 A- 4336 B. 
       FIG. 37  illustrates a perspective view of a biasing member  3302  that may be included in a tack retaining system that includes either wedge  3202 R or the single use wedge (which may include  3202 R but with or without protrusions  3221 R or  3222 R), in accordance with one embodiment. Biasing member  3302  may include a support body  3304 , one or more of locating elements  3335  and  3336 A- 3336 B, and a biasing portion that may be or include leaf spring  3350 . 
     The biasing member  3302  may include a metal, such as steel or another metal or metals, or a nonmetal or nonmetals. In other embodiments, the biasing member  3302  may include plastic or rubber, or a combination of metals, rubbers, and/or plastics, for example. In other embodiments, biasing member  3302  may be formed with, attached to, integral with, or otherwise secured to wedge  3202 R, and may or may not be formed with one or more of the materials of wedge  3202 R. 
     The support body  3304  of the biasing member  3302  may be a thin, flat portion having at least partially rectangular front and back faces  3304 A and  3304 B, which may each share a first side  3306 , second side  3308 , top end  3310 , and bottom end  3312 . In an embodiment, top end  3310  includes recessed portions  3310 A and  3310 B, and/or bottom end  3312  includes recessed portions  3312 A and  3312 B. 
     Locating element  3335  may extend from the support body  3304  at or near the top end  3310 , and may do so from between recessed portions  3310 A and  3310 B. Such a positioning between recessed portions  3310 A and  3310 B may result in certain flexibility and other characteristics of the part of locating element  3335  near recessed portions  3310 A and  3310 B. Recessed portions  3310 A and  3310 B may be altered or omitted in other embodiments as desired. 
     Locating element  3335  may be shaped to conform to a portion of housing  2113  when the security tag  2100  is assembled. For example, in one embodiment, locating element  3335  may have an at least partially capital “L” shaped cross section with a rounded or otherwise curved corner, as viewed from side  3308  of biasing member  3302 . When the security tag  2100  is assembled, the locating element  3335  may be positioned adjacent at least a portion of both back wall  2803 D of wedge compartment  2802  and top surface  2814  of protrusion  2809 , such as shown in the embodiment of  FIG. 40 , which is discussed below. 
     Locating elements  3336 A and  3336 B may extend from support body  3304  at or near bottom end  3312 , and may respectively do so from the portions of bottom end  3312  near or at first side  3306  and second side  3308 . 
     Locating elements  3336 A- 3336 B may each be shaped to conform to a portion of housing  2113  when the security tag  2100  is assembled. For example, in one embodiment, locating elements  3336 A- 3336 B may each have an at least partially “L” shaped cross section with a rounded or otherwise curved corner, as viewed from side  3308  of biasing member  3302 . When the security tag  2100  is assembled, locating element  3336 A may be positioned adjacent at least a portion of each of pocket side walls  28031  and  2803 H of wedge compartment  2802 , and locating element  3336 B may be positioned adjacent at least a portion of each of pocked side walls  2803 F and  2803 G of wedge compartment  2802 , such as shown in the embodiment of  FIG. 40 , which is discussed below. Locating elements  3335  and  3336 A- 3336 B may facilitate positioning of the biasing member  3302  during assembly, and may also provide support to, and restrict movement of, biasing member  3302  during use of security tag  2100 . 
     In one embodiment, when security tag  2100  is assembled, locating elements  3336 A- 3336 B are positioned at least partially over recesses  2822  and  2821 , respectively, of wedge compartment  2802 . In an assembled security tag  2100  that includes wedge  3202 R, locating elements  3336 A- 3336 B may thus restrict movement of wedge protrusions  3221 R- 3222 R out of their respective recesses  2822  and  2821 . Such restriction may increase the difficulty of disabling the tack retaining system without using a detacher. 
     In other embodiments, locating elements  3335  and  3336 A- 3336 B may be partially or fully replaced, changed, and/or supplemented with any other locating elements such as protrusions, recesses, surfaces, or other shapes that may facilitate positioning and possibly also provide support, and may restrict movement of biasing member  3302  during use of security tag  2100 . The locating elements may be spring-like and/or have other characteristics. Recesses  2821 - 2822  may be correspondingly shaped to receive the locating element or elements of the particular embodiment. 
     In an embodiment, the biasing portion of biasing member  3302  is leaf spring  3350 . Leaf spring  3350  may be configured to bias wedge  3202 R or the single-use wedge (wedge  3202 R with or without protrusions  3221 R and  3222 R) in an assembled security tag  2100  toward and into the locked condition in which wedge  3202 R is in engagement with a groove  2108  of tack assembly  2102 , such as described above with respect to embodiments of spring  1302  and wedge  1202  of security tag  102 ,  FIGS. 1-31 . Leaf spring  3350  may also be configured to resist movement of wedge  3202 R out of the locked condition via a range of forces that may accompany many or most unauthorized attempts (e.g., by “slamming” such as described herein, pulling on tack, etc.) to remove security tag  2100  from an article. Leaf spring  3350  may be also be configured, however, to permit a higher range of forces, such as those from a detacher, such as magnetic detaching device  602  of  FIGS. 6-7  in one embodiment, to move the wedge  3202 R out of the locked condition, against the bias of leaf spring  3350 , such as also described with respect to the embodiments of elements  1302 ,  1202  of security tag  102  of  FIGS. 1-31 . Also discussed with respect to that spring  1302  and other components of embodiments of security tag  102  of  FIGS. 1-31 , desired characteristics of leaf spring  3350  may depend upon the characteristics and relative positioning of leaf spring  3350  and also one or more of the wedge  3202 R or other wedge, housing  2113 , and magnetic detaching device  602  or other detacher used in a security tag system. 
     In one embodiment, leaf spring  3350  extends from the support body  3304  at or near the bottom end  3312 , and may do so from the between recessed portions  3312 A and  3312 B. Leaf spring  3350  may have an at least partially “L” shaped cross section with a rounded or otherwise curved corner, as viewed from side  3308  of biasing member  3302 . When the security tag  2100  is assembled, at least a portion of leaf spring  3350  may be positioned adjacent at least a portion of wedge  3202 R, such as shown in the embodiment of  FIG. 40 , or its corresponding single-use version (with or without protrusions  3221 R- 3222 R), for example. The positioning between recessed portions  3312 A and  3312 B and the shape and size of leaf spring  3350  may result in certain spring force and other characteristics to leaf spring  3350 . The recesses and/or size and shape may be altered or omitted in various embodiments based upon the desired characteristics of leaf spring  3350 . For example, in various embodiments, one or more of the length, width, and thickness may be altered, such as based upon the magnetic force characteristics of the associated detacher. 
       FIG. 38  illustrates a perspective view of a biasing member  4302  that may be included in a tack retaining system that includes either wedge  3202 R or the single use wedge (which may include  3202 R but with or without protrusions  3221 R or  3222 R), in accordance with one embodiment. Biasing member  4302  may include a support body  4304 , one or more of locating elements  4335 A- 4335 B and  4336 A- 4336 B, and a biasing portion that may be or include leaf spring  4350 . 
     The biasing member  4302  may include a plastic. In other embodiments, the biasing member  4302  may include metal or rubber, or a combination of metals, rubbers, and/or plastics, for example. 
     The support body  4304  of the biasing member  4302  may be a portion having at least partially rectangular front and back faces  4304 A and  4304 B, and may have a first side  4306 , second side  4308 , top end  4310 , and bottom end  4312 . Support body  4304  may also include portions  4304 C and  4304 D that are angled with respect to adjacent portions of support body  4304 . Those adjacent portions may be parallel or close to parallel such to form a “step” on front face  4304 A on either side of the central portion  4304 E of support body  4304 . 
     Locating elements  4335 A- 4335 B may extend from the support body  4304  back face  4304 B. Locating elements  4335 A- 4335 B may be shaped to conform to a portion of housing  2113  when the security tag  2100  is assembled. For example, in one embodiment, locating elements  4335 A- 4335 B may be convex protrusions that conform to the recesses formed by back wall portions  2804 A and  2804 B of back wall  2803 D of wedge compartment  2802  of housing  2113 , such as shown in the embodiment of  FIG. 41 , which is discussed below. 
     Locating element  4336 A and  4336 B may extend from the support body  4304  along first and second sides  4306  and  4308 , respectively, and may also be shaped to conform to a portion of housing  2113  when the security tag  2100  is assembled. For example, in one embodiment, locating elements  4336 A- 4336 B may each extend approximately perpendicular to central portion  4304 E of support body  4304 . When the security tag  2100  is assembled, locating element  4336 A may be positioned adjacent at least a portion of each of pocket side walls  28031  and  2803 H of wedge compartment  2802 , and locating element  4336 B may be positioned adjacent at least a portion of each of pocked side walls  2803 F and  2803 G of wedge compartment  2802 , such as shown in the embodiment of  FIG. 41 , which is described below. Locating elements  4335 A- 4335 B and  4336 A- 4336 B may facilitate positioning of the biasing member  3302  during assembly, and may also provide support to, and restrict movement of, biasing member  4302  during use of security tag  2100 . 
     In one embodiment, when a reusable security tag  2100  is assembled, locating elements  4336 A- 4336 B are respectively positioned at least partially over recesses  2822  and  2821 , thus restricting movement of protrusions  3221 R- 3222 R of wedge  3202 R, such as shown in the embodiment of  FIG. 41  and described with respect to locating elements  3336 A- 3336 B of biasing member  3302  of  FIGS. 37 and 40 . 
     In an embodiment, the biasing portion of biasing member  4302  is leaf spring  4350 . Leaf spring  4350  may be configured and positioned to provide an appropriate bias to wedge  3202 R or the single-use wedge (wedge  3202 R with or without protrusions  3221 R and  3222 R) in an assembled security tag  2100 , such as described with respect to leaf spring  3350  of biasing member  3302  of  FIGS. 37 and 40 . In one embodiment, leaf spring  4350  extends from the support body  4304  at or near the bottom end  4310 , and has an at least partially rectangular, flat shape. 
     In various other embodiments, biasing member  3302  or  4302  may be otherwise configured to fit at least partially within wedge compartment  2802  of upper housing  2114 , and be secured therein. For example, biasing member  3302  or  4302  may include only the biasing portion, leaf spring  3350  or  4350 , respectively, without locating elements or a support body apart from housing  2113 . Instead, leaf spring  3350  or  4350  may be integral with or otherwise secured at one end to a portion of housing  2113 , such as to a portion of wall  2803 . In other embodiments, one or more locating elements of either biasing member  3302  or  4302  may be altered or omitted, or other locating elements may be added. 
     For example, in one embodiment, biasing member  3302  is integral with housing  2113  of security tag  2100 . The support body  3304  may thus be housing  2113  or a portion thereof, in which case locating elements  3335  and  3336 A- 3336 B may be excluded from biasing member  3302 . Leaf spring  3350  of biasing member  3302  may be a leaf spring that extends from back wall  2803 D of housing  2113 . 
       FIG. 39  illustrates an interior partial view of an upper housing  2114  with a wedge  3202 R inserted for a security tag  2100 , in accordance with one embodiment. In this embodiment, wedge  3202 R of a tack retaining system is disposed in the wedge compartment  2802  such that protrusions  3221 R and  3222 R are respectively disposed at least partially within recesses  2822  and  2821 . The tack retaining portion of wedge  3202 R may be positioned to engage a lip  2107  of a groove  2108  of an inserted tack assembly  2102  in the locked condition, such as with either or both edges  3226 R and  3213 R, and/or one or more wedge surfaces  3209 R,  3223 R, and  3228 R. 
     In an embodiment in which wedge  3202 R is symmetrical, such as described in embodiments above, wedge  3202 R may be in a “flipped” orientation such that protrusions  3221 R and  3222 R are respectively disposed at least partially within recesses  2821  and  2822 . This may result fewer errors in assembly. Such symmetry may also simplify manufacturing of wedge  3202 R. 
     In a single use embodiment of the wedge (wedge  3202 R with or without protrusions  3221 R- 3222 R) the wedge may be similarly positioned, except that no portion of the wedge may be disposed within either recess  2821  or  2822 . The single use wedge may be substituted for wedge  3202 R in either of the embodiments of  FIGS. 40-41  below. 
       FIG. 40  illustrates an interior partial view of an upper housing  2114  with a wedge  3202 R and biasing member  3302  inserted for a security tag  2100 , in accordance with one embodiment. As shown in this embodiment, biasing member  3302  is positioned adjacent wedge  3202 R and closely within walls  2803  of wedge compartment  2802 . Such positioning may restrict movement of protrusions  3221 R and  3222 R of wedge  3202 R out of their respective recesses  2822  and  2821 . Biasing member  3302  may allow at least rotational movement of wedge  3202 R about protrusions  3221 R and  3222 R during operation of security tag  2100 , such as described above with respect to axle protrusions  1221 R and  1222 R of wedge  1202 R and recesses  821  and  822  of security tag  100 . 
       FIG. 41  illustrates an interior partial view of an upper housing  2114  with a wedge  3202 R and biasing member  4302  inserted for a security tag  2100 , in accordance with one embodiment. As shown in this embodiment, biasing member  4302  is positioned adjacent wedge  3202 R and closely within walls  2803  of wedge compartment  2802 . Biasing member  4302  may restrict movement of protrusions  3221 R and  3222 R of wedge  3202 R out of their respective recesses  2822  and  2821 , but may allow at least rotational movement about protrusions  3221 R and  3222 R during operation of security tag  2100 , such as described above with respect to axle protrusions  1221 R and  1222 R of wedge  1202 R and recesses  821  and  822  of security tag  100 . 
       FIG. 42  illustrates a first partial view of a cross-section (taken along line D-D of  FIG. 32 ) of a reusable security tag  2100  with a tack  2102  and a tack retaining system including wedge  3202 R and biasing member  3302 , in accordance with one embodiment.  FIG. 42  may correspond to  FIG. 14 , in that tack shank  2106  of tack assembly  2102  may be partially inserted into tack hole  2807 , but not yet in contact with wedge  3202 R. The tack retaining system may be in the rest condition in its original position. Wedge  3202 R may be biased by leaf spring  3350  of biasing member  3202  at a wedge angle θ1, such that surface  3205 R is on wedge stop  2902  and edge  3216 R is on sloped surface  2808   a  of top wall  2808 A. Wedge angle θ1 may be an angle such as the approximately 22° and Ø in the embodiment of  FIG. 14 , or may be another angle. In one embodiment, top wall  2808 A does not include sloped surface  2808   a . Wedge protrusions  3221 R and  3222 R (not shown) may be constrained to their respective recesses  2822  and  2821  (not shown), but may be allowed to rotate, translate, some combination of rotation and translation, or otherwise move within recesses  2822  and  2821 . 
       FIG. 43  illustrates a second partial view of a cross-section (taken along line D-D of  FIG. 32 ) of a reusable security tag  2100  with a tack  2102  and a tack retaining system including wedge  3202 R and biasing member  3302 , in accordance with one embodiment.  FIG. 43  may correspond to  FIG. 17 , in that tack shank  2106  of tack assembly  2102  may be further inserted into tack hole  2807  such that a tack groove  2108  is adjacent tack retaining portion of wedge  3202 R. The tack retaining portion may include one or more chamfers such as described above and may include surfaces  3209 R,  3223 R, and  3228 R and their common edges  3213 R and  3226 R. At this point, leaf spring  3350  of biasing member  3302  may force the chamfered tack retaining portion of wedge  3202 R at least partially into tack groove  2108 . Attempts to retract tack assembly  2102  from security tag  2100  may now be prevented or made more difficult by the wedge  3202 R, since edges  3213 R and  3226 R may now be biased into a position adjacent the intersection of groove lip  2107  and the surface between lips  2107  and  2109  of tack groove  2108  by leaf spring  3350  of biasing member  3302 , thus restraining tack  2102  from being extracted from tag  2100 . At this point, the reusable tack retaining system may be in a locked condition. 
       FIG. 44  illustrates a third partial view of a cross-section (taken along line D-D of  FIG. 32 ) of a reusable security tag  2100  with a tack  2102  and a tack retaining system including wedge  3202 R and biasing member  3302 , in accordance with one embodiment. In this embodiment, housing  2113  includes a stop  5000  that may restrict wedge  3202 R from rotating past stop  5000 . Stop  5000  may thus reduce the bending of spring  3350  caused by movement, via the magnetic force of magnetic detaching device  602  of  FIGS. 6-7  or another detacher, of adjacent wedge  3202 R out of the locked condition. By limiting its bending, spring  3350  may preserve or nearly preserve its characteristics to provide desired biasing forces to wedge  3202 R, such as discussed above, during subsequent use. 
       FIG. 45  illustrates a partial view of a cross-section (taken along line E-E of  FIG. 32 ) of a reusable security tag  2100  having a tack retaining system including wedge  3202 R and biasing member  3302 , and a tack  2102 , in accordance with one embodiment. This figure shows another view of an embodiment in which locating element  3336 A is positioned at least partially over recess  2822 , restricting movement of wedge protrusion  3221 R out of recess  2822 , such as described above. 
       FIG. 46  illustrates a first partial view of a cross-section (taken along line D-D of  FIG. 32 ) of a single-use security tag  2100  with a tack  2102  and a tack retaining system. In this embodiment, the tack retaining system includes a single use wedge (wedge  3202 R with or without protrusions  3221 R- 3222 R) and a biasing member  3302 . For example, in an embodiment, the tack retaining system includes wedge  3202 R (i.e. with protrusions  3221 R- 3222 R) as the single use wedge, and biasing member  3302  may not include locating elements  3336 A- 3336 B. In the embodiment as shown in  FIG. 46 , biasing member  3302  includes locating elements  3336 A- 3336 B ( 3336 A not shown), but locating elements  3336 A- 3336 B are positioned such that they extend from a portion of biasing member  3302  that is closer to top end  3310  as compared to the embodiment of  FIG. 37 . In such position, locating elements  3336 A- 3336 B may not restrict movement of wedge protrusions  3221 R- 3222 R out of their respective housing recesses  2822 - 2821 . Locating elements  3336 A- 3336 B may be otherwise positioned and/or shaped to allow wedge protrusions  3221 R- 3222 R to move out of their respective recesses  2822 - 2821 . In an embodiment of security tag  2100  employing biasing member  4302 , such as shown in  FIG. 38  described above, locating elements  4336 A- 4336 B of biasing member  4302  may also be excluded, positioned and/or shaped to allow wedge protrusions  3221 R- 3222 R of a single use wedge  3202 R to move out of their respective recesses  2822 - 2821 . 
     The single use wedge may be biased by leaf spring  3350  of biasing member  3302  to an original position at a wedge angle θ2 (which may correspond to the position of wedge  3202 R at wedge angle θ1), such that surface  3205 R is originally on wedge stop  2902  and edge  3216 R is on sloped surface  2808   a  of top wall  2808 A (position not shown, but may correspond to position of wedge  3202 R in  FIG. 42 ). Wedge angle θ2 may be an angle such as the approximately 22° and Ø in the embodiment of  FIG. 14 , or may be another angle. In another embodiment, top wall  2808 A does not include sloped surface  2808   a.    
     In one embodiment, tack assembly  2102  may be removed or detached from security tag  2100  as implemented with a single-use tack retaining system through use of a magnetic detaching device (e.g.  602 ), such as described above with respect to tack assembly  102  and security tag  100 , for example. Thus, in order to detach tack assembly  2102  from security tag  2100 , security tag  2100  may be seated or nearly seated in magnetic detaching device  602 . Detaching device  602  may magnetically force the single use wedge against leaf spring  3350  of biasing member  3302 , such as by rotational movement about wedge pivot side  3207 R, translational movement, some combination of rotational and translational movement, and/or other movement out of the locked condition and past stop  5110 . The single use wedge, now unblocked by tack shank  2106  or stop  5110 , may be further magnetically forced from a position above trap cavity  5100  to a position partially within trap cavity  5100  such as shown. Trap cavity  5100  may be a cavity or other recessed portion of lower housing  2116 . Trap cavity  5100  may be at least partially cuboidal in shape or otherwise shaped to receive at least a portion of the single use wedge. 
       FIG. 47  illustrates a second partial view of the embodiment of  FIG. 46 , in which the single use wedge has moved by magnetic force further into trap cavity  5100 , and may remain in this position or nearly in this position (without an external force such as described below with respect to  FIG. 48 ) once security tag  2100  has been removed from the detaching device. 
       FIG. 48  illustrates a third partial view of the embodiment of  FIG. 46 , in which the single use wedge had completed movement via magnetic force into trap cavity  5100 , and security tag  2100  has been removed from detaching device  602 . Since detaching device  602  may thus no longer be biasing the single use wedge against leaf spring  3350  of biasing member  3302 , leaf spring  3350  may bias the wedge against trap cavity sidewall  5100 A. An external force (e.g., caused by “slamming” as described herein, gravity, etc.) applied to the single use wedge may tend to move the wedge in a direction out of trap cavity  5100 , such as by partially translational, partially rotational, and/or other movement. In one embodiment, housing  2113  includes a wedge catch  5120 , which may be a cavity or other recess shaped to receive a portion of the single use wedge, such as a portion near wedge pivot side  3207 R. The wedge catch  5120  may receive this wedge portion, such as shown, during movement of the single use wedge by external force out of the trap cavity  5100 . Thus, the single use wedge, disposed at least partially within both trap cavity  5100  and wedge catch  5120 , and biased by leaf spring  3350  to remain so, may no longer be able to engage a tack shank  2106  of a tack assembly  2102  in the locked condition, rendering security tag  2100  inoperable. 
     In any of the single use or reusable embodiments described above with respect to security tag  2100 , the tack retaining system may include an alternative to biasing member  3302  or  4302 .  FIGS. 49-53  show various alternative embodiments. In these alternative embodiments, the wedge is identified in the figures as wedge  3202 R. However, in an embodiment where the particular security tag  6100 ,  7100 ,  8100 ,  9100 , or  10100  of one of  FIGS. 49-53  is to be for single use, the wedge used may be  3202 R with or without protrusions  3221 R- 3222 R. Other portions of that security tag, such as its corresponding biasing member  6350 ,  7350 ,  8350 ,  9350 , or  10350 , may be appropriately shaped and/or positioned, such as, where applicable, to allow movement of protrusions  3221 R- 3222 R out of their respective housing recesses  2822 - 2821 . Such shaping and/or positioning may be as described above with respect to single use tack retaining systems using wedge  3202 R (with or without protrusions  3221 R- 3222 R) and biasing member  3302  or  4302 . 
       FIG. 49  illustrates a partial view of a cross-section (taken along a line corresponding to line D-D of  FIG. 32 ) of a security tag  6100  having an alternative embodiment of a biasing member, and a tack  2102 . Other portions of security tag  6100 , as well as security tags  7100 ,  8100 ,  9100 , and  10100  (described below) that are not shown may include elements that are the same or similar to those of security tag  2100 . 
     In this embodiment, the tack retaining system includes a biasing member  6302  that includes a biasing portion that is wedge-bending element  6350 , which may block free rotational movement of wedge  3202 R (whether including protrusions  3221 R- 3222 R) or its single use version about wedge pivot side  3207 R. Wedge-bending element  6350  may be a thin plastic member in one embodiment. Wedge-bending element  6350  may protrude from wall  3111 B or another wall and be integral with, or otherwise secured to, housing  2113  of security tag  2100 . In one embodiment, wedge-bending element  6350  is integral with lower housing  2116 . 
     Wedge-bending element  6350  may cause wedge  3202 R to bend around wedge-bending element end  6350 A when tack shank  2106  is inserted into security tag  2100  and contacts wedge  3202 R, causing wedge  3202 R to be biased toward the locked condition in engagement with a groove  2108  of tack shank  2106 . During detachment, magnetic detaching device  602  or another detaching device may cause wedge  3202 R to further bend out of groove  2108  such that tack assembly  2102  may be removed from security tag  6100 . When security tag  6100  is removed from the detacher, if wedge  3202 R is made of material and/or shaped such that it is resilient, wedge  3202 R may return to its original shape, or close thereto, such that security tag  6100  may be reused. In an embodiment in which such material is not resilient, wedge  3202 R may remain bent and security tag  6100  may be for single use. 
     In other embodiments of security tag  6100 , wedge  3202 R may be replaced with its corresponding single use wedge with or without protrusions  3221 R- 3222 R, or may use another wedge configured to bend around wedge-bending element  6350  under force and to engage tack shank  2106  in the locked condition. 
       FIG. 50  illustrates a partial view of a cross-section (taken along a line corresponding to line D-D of  FIG. 32 ) of a security tag  7100  having another embodiment of a biasing member, and a tack  2102 . In this embodiment, tack retaining system includes a biasing member  7302  with a biasing portion that is a torsion spring  7350 . Torsion spring  7350  may bias wedge  3202 R or another wedge toward the locking position, such as described with respect to leaf spring  3350  of biasing member  3202 . Torsion spring  7350  may be integral with or secured to housing  2113 , or may otherwise be configured and/or disposed in wedge compartment  2802  to restrain movement of the part of biasing member  7302  other than torsion spring  7350 . 
       FIG. 51  illustrates a partial view of a cross-section (taken along a line corresponding to line D-D of  FIG. 32 ) of a security tag  8100 , having another embodiment of a biasing member, and a tack  2102 . In this embodiment, the tack retaining system includes a biasing member  8302  with a biasing portion that is a leaf spring  8350  that is secured to housing  2113  and may have a curved end that biases wedge  3202 R (or another wedge) toward the locked condition. Leaf spring  8350  may be secured to housing  2113 , for example, by being embedded within lower housing  2116  and/or secured by an epoxy, or otherwise secured. 
       FIG. 52  illustrates a partial view of a cross-section (taken along a line corresponding to line D-D of  FIG. 32 ) of a security tag  9100  with a tack  2102  and another embodiment of a biasing member. In this embodiment, leaf spring  8350  of biasing member  8302  has been replaced by wire spring  9350 A or  9350 B of biasing member  9302  to provide the biasing force to wedge  3202 R or another wedge. The wire spring may be formed of various shapes other than the ones shown in various embodiments. 
       FIG. 53  illustrates a partial view of a cross-section (taken along a line corresponding to line D-D of  FIG. 32 ) of a security tag  10100  with a tack  2102  and another embodiment of a biasing member. In this embodiment, leaf spring  8350  of biasing member  8302  has been replaced by compression spring  10350  of biasing member  10302  to provide the biasing force to wedge  3202 R or another wedge for security tag  10100 . Compression spring  10350  may be secured to wedge  3202 R at spring support  10360 , such as by being integral, by being secured by epoxy and/or friction, or by another securing means, or may not be secured thereto. 
     In another embodiment as shown in  FIGS. 54-56 , security tag  11100  may be resettable. Security tag  11100  in these figures may be similar to the embodiment of security tag  2100  of  FIGS. 46-48 , except in this embodiment wedge catch  5120  has been replaced by guiding ramp  11120 . Guiding ramp  11120  may be a curved portion of upper housing  2114  and may be, in various embodiments, one or more ramped portions in which wedge  3202 R may contact and slide against to guide movement of wedge  3202 R from and back to its original position, such as shown in  FIG. 56  described below. For example, in one such embodiment, guiding ramp  11120  includes two ramps each aligned such that one of the wedge protrusions  3221 R- 3222 R of wedge  3202 R may slide along a ramp during movement of wedge  3202 R during operation of security tag  11100 , such as described below. 
       FIG. 54  illustrates a first partial view of a cross-section (taken along a line corresponding to line D-D of  FIG. 32 ) of a resettable security tag  11100  and a tack  2102 , in accordance with one embodiment. The security tag  11100  as shown in  FIG. 54  may correspond to that of  FIG. 46  such that the wedge  3202 R has moved out of its original position by magnetic force from a detaching device to a position partially within trap cavity  5100 . 
       FIG. 55  illustrates a second partial view of a cross-section (taken along a line corresponding to line D-D of  FIG. 32 ) of a resettable security tag  11100  and a tack  2102 , in accordance with one embodiment. The security tag  2100  of  FIG. 55  may correspond to that of  FIG. 47  such that wedge  3202 R has moved further into trap cavity  5100 . 
       FIG. 56  illustrates a third partial view of a cross-section (taken along a line corresponding to line D-D of  FIG. 32 ) of a resettable security tag  11100  and a magnetic device  11300  for resetting the security tag, in accordance with one embodiment. In this embodiment, wedge  3202 R may be reset from the position of wedge  3202 R in  FIG. 55 , such as at a customer site or factory, by force of magnetic device  11300 . Magnetic device  11300  may cause movement of wedge  3202 R back to the original position of wedge  3202 R as shown, such that wedge  3202 R is operable again. This movement may include sliding of wedge  3202 R along guiding ramp  11120  and/or other movement. 
     One or more of the security tag embodiments described above, such as security tag  6100 ,  7100 ,  8100 ,  9100 ,  10100 , and  11100  in addition to embodiments of security tags  2100  may be detached from an article  202  using a magnetic detaching device, such as the magnetic detaching device  602  of  FIG. 6 , which may be shaped to receive at least a portion of the particular security tag. For example, in one embodiment, tag receiving hole  611  of magnetic security device  602  may be shaped to receive at least a portion of protrusion  2124  of security tag  2100 . 
     In any of the aforementioned security tag embodiments of  FIGS. 32-56 , embodiments of spring  1302  of  FIGS. 1-31  may replace the biasing element, and any embodiments of wedge  1202  of  FIGS. 1-31  may replace the wedge  3202 R or other wedge. 
     Numerous specific details have been set forth herein to provide a thorough understanding of the embodiments. It will be understood by those skilled in the art, however, that the embodiments may be practiced without these specific details. In other instances, well-known operations, components and circuits have not been described in detail so as not to obscure the embodiments. It can be appreciated that the specific structural and functional details disclosed herein may be representative and do not necessarily limit the scope of the embodiments. 
     It is also worthy to note that any reference to “one embodiment” or “an embodiment” means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment. The appearances of the phrase “in one embodiment” in various places in the specification are not necessarily all referring to the same embodiment. 
     While certain features of the embodiments have been illustrated as described herein, many modifications, substitutions, changes and equivalents will now occur to those skilled in the art. It is therefore to be understood that the appended claims are intended to cover all such modifications and changes as fall within the true spirit of the embodiments.