Patent Description:
Electronic Article Surveillance ("EAS") systems are often used by retail stores in order to minimize loss due to theft. One common way to minimize retail theft is to attach a security tag to an article such that an unauthorized removal of the article can be detected. In some scenarios, a visual or audible alarm is generated based on such detection. For example, a security tag with an EAS element (e.g., an acousto-magnetic element) can be attached to an article offered for sale by a retail store. An EAS interrogation signal is transmitted at the entrance and/or exit of the retail store. The EAS interrogation signal causes the EAS element of the security tag to produce a detectable response if an attempt is made to remove the article without first detaching the security tag therefrom. The security tag must be detached from the article upon purchase thereof in order to prevent the visual or audible alarm from being generated.

One type of security tag can include a tag body which engages a tack. The tack usually includes a tack head and a sharpened pin extending from the tack head. In use, the pin is inserted through the article to be protected. The shank or lower part of the pin is then locked within a cooperating aperture formed through the housing of the tag body. In some scenarios, the tag body may contain a Radio Frequency Identification ("RFID") element or label. The RFID element can be interrogated by an RFID reader to obtain RFID data therefrom.

The security tag may be removed or detached from the article using a detaching unit. Examples of such detaching units are disclosed in <CIT> ("the '<NUM> patent application) and <CIT> ("the '<NUM> patent"). The detaching units disclosed in the listed patents are designed to operate upon a two-part hard security tag. Such a security tag comprises a pin and a molded plastic enclosure housing EAS marker elements. During operation, the pin is inserted through an article to be protected (e.g., a piece of clothing) and into an aperture formed through at least one sidewall of the molded plastic enclosure. The pin is securely coupled to the molded plastic enclosure via a mechanical or magnetic locking mechanism disposed therein. The pin is released by a detaching unit via application of a magnetic field by a magnet or mechanical probe inserted through an aperture in the hard tag. The magnet or mechanical probe is normally in a non-detach position within the detaching unit. When the RFID enabled hard tag is inserted into the RFID detacher nest, a first magnetic field or mechanical clamp is applied to hold the tag in place while the POS transaction is verified. Once the transaction and payment have been verified, the second magnet or the mechanical probe is caused to travel from the non-detach position to a detach position so as to release the tag's locking mechanism (e.g., a clamp). The pin can now be removed from the tag. Once the pin is removed and the article is released, the security tag will be ejected or unclamped from the detacher nest.

The mechanical and magnetic locking mechanisms of the security tags have certain drawbacks. For example, magnetic locks suffer from a common problem which allows the lock to be momentarily unlatched when the security tag is impacted upon a hard surface. The amount of force required to cause unlocking is dependent upon the design of the lock, and more particularly upon a spring that is used to retain the lock in a latched condition. Lighter springs exerting less spring force are designed to work with lower strength magnetic detaching units and heavier springs exerting more spring force are designed to work with higher strength magnetic detaching units. But regardless of spring weight used, the un-authorized unlocking of security tags by striking them upon a surface is known problem, as disclosed in <CIT> wherein a solution against an attempt to effect unauthorized removal of a security tag pin by impact force is presented using floating plunger elements. Thus, without a solution against unauthorized removal of a security tag pin by impact force, the spring which retains the security tags in a locked condition will compress and the lock will momentarily transition to an unlocked condition.

The present invention as defined by the appended method and device claims concerns systems and methods for operating a security tag.

The methods comprise: causing a plunger of the security tag to engage a latch of the security tag; preventing, by an anti-defeat structure of the security tag, a disengagement between the plunger and the latch when an impact force is applied to the security tag; and allowing, by the anti-defeat structure, the plunger to disengage the latch when a magnetic field is applied to the security tag.

The anti-defeat structure prevents the plunger's disengagement from the latch when an impact force is applied to the security tag by absorbing energy due to the impact force and releasing the energy to provide a reactionary impulse force in a direction towards the latch. The reactionary impulse force causes the plunger to be pushed in a direction towards the latch prior to when the plunger travels out of the latch as a result of the impact force.

According to the invention, the anti-defeat structure comprises an impact mass that is resiliently biased towards the plunger by an impact spring. The impact mass is disposed between the plunger and the impact spring, and is in contact with the plunger at all times. The impact spring is in a compressed state when the energy is being absorbed by the anti-defeat structure, and transitions from the compressed state to an uncompressed state when the anti-defeat structure releases the energy. The impact spring causes the impact mass to apply a pushing force to the plunger as the energy is being released by the anti-defeat structure. The pushing force causes the plunger to travel towards the latch and remain engaged with the latch despite the application of the impact force.

The anti-defeat structure allows the plunger's disengagement from the latch when the magnetic field is being applied to the security tag by absorbing energy while the plunger is being attracted to a magnetic field source. The anti-defeat structure allows the plunger to travel a first distance in a direction away from the latch when the magnetic field is being applied to the security tag, and a second distance in a direction away from the latch when the impact force is being applied to the security tag. The first distance is greater than the second distance.

The present solution will be described with reference to the following drawing figures, in which like numerals represent like items throughout the figures.

It will be readily understood that the components of the embodiments as generally described herein and illustrated in the appended figures could be arranged and designed in a wide variety of different configurations without departing from the scope of the invention as defined in the appended claims. Thus, the following more detailed description of various embodiments, as represented in the figures, is not intended to limit the scope of the present invention, but is merely representative of various embodiments.

The present invention may be embodied in other specific forms. The described embodiments are to be considered in all respects only as illustrative and not restrictive. The scope of the invention is, therefore, indicated by the appended claims rather than by this detailed description. All changes which come within the meaning and range of equivalency of the claims are to be embraced within their scope.

The present solution concerns a magnetic lock mechanism for a security tag that is resistant to defeat caused by forceful impacts, such as when the security tag is dropped or forcefully slammed on a hard surface. The security tag includes a housing formed of a rigid material, such as injection molded plastic. A pin channel is defined within the housing. The pin channel is arranged to removably receive therein a pin along a pin channel axis. A latch assembly is disposed within the housing which includes a latch disposed adjacent to the pin channel. The latch is configured to lockingly engage the pin when in a locked position, and is configured to release the pin when moved to an unlocked position.

The latch assembly also includes a plunger formed of material responsive to an applied magnetic field. The plunger has an engagement face which interacts with a base portion of the latch. A plunger guide channel is formed in the housing and is arranged to facilitate translational movement of the plunger along a guide channel axis. The plunger can thus move from a first position to a second position within the guide channel when the plunger is exposed to the applied magnetic field. A resilient member (such as a latch spring) is arranged to resiliently urge the engagement face of the plunger into contact with a base of the latch. The latch is responsive to the translational movement of the plunger from the unlocked position to the locked position to cause the latch to move from the locked position to the unlocked position described above.

An impulse mass is disposed within the housing so as to be adjacent to the end of the plunger opposite the engagement face. A portion of the housing is configured to hold the impulse mass in a variable given position relative to the housing. In some scenarios, a slot can be formed in the housing into which the impulse mass can be pressed into or otherwise inserted.

The impulse mass may have a recess configured to receive a portion of the end of the plunger to help prevent the plunger from being dislodged from the plunger guide channel. The impulse mass can be formed of metal, and is configured and arranged to absorb shock when the tag is dropped or forcefully slammed in an attempt to defeat the tag, thus preventing the plunger from being urged into the unlocking position.

An impulse spring is disposed between the housing walls and the impulse mass, or is otherwise positioned between a fixed member within the housing and the impulse mass. The impulse spring is arranged and positioned to axially bias the impulse mass against the plunger such that the plunger is urged towards the first position.

When the security tag is subjected to a dropping/slamming force, the impulse spring begins to oscillate as a result. When a forceful blow starts to displace the latch from the locking position, the impulse mass is slammed against the plunger, which transfers the force towards the latch mechanism, thereby biasing the latch mechanism in the locking position. As a result, the locking mechanism does not unlatch. The inventive arrangement therefore serves to utilize the destructive force applied to the tag to more securely lock the tag.

Referring now to <FIG>, there is provided an illustration of an illustrative EAS system <NUM>. EAS systems are well known in the art, and therefore will not be described in detail herein. Still, it should be understood that the present solution will be described herein in relation to an acousto-magnetic (or magnetostrictive) EAS system. The present solution is not limited in this regard. The EAS system <NUM> may alternatively include a magnetic EAS system, an RF EAS system, a microwave EAS system or other type of EAS system. In all cases, the EAS system <NUM> generally prevents the unauthorized removal of articles from a retail store.

In this regard, security tags <NUM> are securely coupled to articles (e.g., clothing, toys, and other merchandise) offered for sale by the retail store. Illustrative architectures of the security tags <NUM> will be described below in relation to <FIG>. At the exits of the retail store, detection equipment <NUM> sounds an alarm or otherwise alerts store employees when it senses an active security tag <NUM> in proximity thereto. Such an alarm or alert provide notification to store employees of an attempt to remove an article from the retail store without proper authorization.

In some scenarios, the detection equipment <NUM> comprises antenna pedestals <NUM>, <NUM> and an electronic unit <NUM>. The antenna pedestals <NUM>, <NUM> are configured to create a surveillance zone at the exit or checkout lane of the retail store by transmitting an EAS interrogation signal. The EAS interrogation signal causes an active security tag <NUM> to produce a detectable response if an attempt is made to remove the article from the retail store. For example, the security tag <NUM> can cause perturbations in the interrogation signal, as will be described in detail below.

The antenna pedestals <NUM>, <NUM> may also be configured to act as RFID readers. In these scenarios, the antenna pedestals <NUM>, <NUM> transmit an RFID interrogation signal for purposes of obtaining RFID data from the active security tag <NUM>. The RFID data can include, but is not limited to, a unique identifier for the active security tag <NUM>. In other scenarios, these RFID functions are provided by devices separate and apart from the antenna pedestals.

The security tag <NUM> can be deactivated and detached from the article using a detaching unit <NUM>. Typically, the security tag <NUM> is removed or detached from the articles by store employees when the corresponding article has been purchased or has been otherwise authorized for removal from the retail store. The detaching unit <NUM> is located at a checkout counter <NUM> of the retail store and communicatively coupled to a POS terminal <NUM> via a wired link <NUM>. In general, the POS terminal <NUM> facilitates the purchase of articles from the retail store.

Detaching units and POS terminals are well known in the art, and therefore will not be described herein. The POS terminal <NUM> can include any known or to be known POS terminal with or without any modifications thereto. However, the detaching unit <NUM> includes any known or to be known detaching unit selected in accordance with a particular application which has some hardware and/or software modifications made thereto so as to facilitate the implementation of the present solution (which will become more evident below). The hardware and/or software modifications can include, but are not limited to, an inclusion of an RFID enabled device to facilitate RF communications with security tags and/or a coil for selectively emitting energy that is to be harvested by security tags.

In some cases, the detaching unit <NUM> is configured to operate as an RFID reader. As such, the detaching unit <NUM> may transmit an RFID interrogation signal for purposes of obtaining RFID data from a security tag. Upon receipt of the tag's unique identifier and/or an article's identifier, the detaching unit <NUM> communicates the same to the POS terminal <NUM>. At the POS terminal <NUM>, a determination is made as to whether the received identifier(s) is(are) valid for a security tag of the retail store. If it is determined that the received identifier(s) is(are) valid for a security tag of the retail store, then the POS terminal <NUM> notifies the detaching unit <NUM> that the same has been validated, and therefore the security tag <NUM> can be removed from the article.

At this time, the detaching unit <NUM> performs operations to apply a magnetic field to the security tag <NUM>. In response to the magnetic field, a pin is released from a lock mechanism of the security tag <NUM>. The pin is now able to be removed from the security tag, whereby the security tag is detached from an article.

Referring now to <FIG>, there is provided an illustration of an illustrative architecture for a data network <NUM> in which the various components of the EAS system <NUM> are coupled together. Data network <NUM> comprises a host computing device <NUM> which stores data concerning at least one of merchandise identification, inventory, and pricing. A first data signal path <NUM> allows for two-way data communication between the host computing device <NUM> and the POS terminal <NUM>. A second data signal path <NUM> permits data communication between the host computing device <NUM> and a programming unit <NUM>. The programming unit <NUM> is generally configured to write product identifying data and other information into memory of the security tag <NUM>. A third data signal path <NUM> permits data communication between the host computing device <NUM> and a base station <NUM>. The base station <NUM> is in wireless communication with a portable read/write unit <NUM>. The portable read/write unit <NUM> reads data from the security tags for purposes of determining the inventory of the retail store, as well as writes data to the security tags. Data can be written to the security tags when they are applied to articles of merchandise.

Referring now to <FIG>, there are provided illustrations of an illustrative architecture for the security tag <NUM>. Security tag <NUM> can include more or less components than that shown in <FIG>. However, the components shown are sufficient to disclose an illustrative embodiment implementing the present solution. Some or all of the components of the security tag <NUM> can be implemented in hardware, software and/or a combination of hardware and software. The hardware includes, but is not limited to, one or more electronic circuits. The hardware architecture of <FIG> represents a representative security tag configured to facilitate the prevention of an unauthorized removal of an article from a retail store facility.

As shown in <FIG>, the security tag <NUM> comprises an antenna <NUM> and an RF enabled device <NUM>. The RF enabled device <NUM> allows data to be exchanged with the external device via RF technology. The antenna <NUM> is configured to receive RF signals from the external device and transmit RF signals generated by the RF enabled device <NUM>. The RF enabled device <NUM> comprises an RF transceiver <NUM>. RF transceivers are well known in the art, and therefore will not be described herein. Any known or to be known RF transceiver can be used here.

The security tag <NUM> also comprises a magnetic lock mechanism <NUM> and a pin (or tack) <NUM> for securing the security tag to an article. Magnetic lock mechanisms and pins are well known in the art, and therefore will not be described here in detail. In some scenarios, the magnetic lock mechanism comprises a plunger <NUM> that transitions between an engaged position in which the plunger <NUM> prevents the pin (or tack) <NUM> from being removed from the security tag <NUM> to an unengaged position in which the pin (or tack) <NUM> is no longer prevented from being removed from the security tag <NUM> by the pin (or tack) <NUM>. The pin (or tack) <NUM> is secured to the security tag <NUM> via a latch <NUM> of the magnetic lock mechanism <NUM> that is engaged by the plunger <NUM>. The pin (or tack) <NUM> is released from the magnetic lock mechanism <NUM> when the plunger <NUM> is disengaged from the latch <NUM> via an application of a magnetic field to the magnetic lock mechanism <NUM>. The magnetic field is generated by the detaching unit <NUM> during a detachment process.

During the detachment process, the RF transceiver <NUM> may receive an RF signal from the detaching unit <NUM>. A controller <NUM> of the security tag <NUM> processes the received RF signal to extract information therein. This information can include, but is not limited to, a request for certain information (e.g., a unique identifier <NUM>). If the extracted information includes a request for certain information, then the controller <NUM> may perform operations to retrieve a unique identifier <NUM> from memory <NUM>. The retrieved information is then sent from the security tag <NUM> to the detaching unit <NUM> via an RF communication facilitated by the RF transceiver <NUM>.

Memory <NUM> may be a volatile memory and/or a non-volatile memory. For example, the memory <NUM> can include, but is not limited to, a Random Access Memory ("RAM"), a Dynamic Random Access Memory ("DRAM"), a Static Random Access Memory ("SRAM"), a Read-Only Memory ("ROM") and a flash memory. The memory <NUM> may also comprise unsecure memory and/or secure memory. The phrase "unsecure memory", as used herein, refers to memory configured to store data in a plain text form. The phrase "secure memory", as used herein, refers to memory configured to store data in an encrypted form and/or memory having or being disposed in a secure or tamper-proof enclosure.

The security tag <NUM> further comprises an anti-defeat impact protection mechanism <NUM>. The anti-defeat impact protection mechanism <NUM> is provided to prevent an unlocking of the magnetic lock mechanism <NUM> as a result of forceful impacts to the security tag <NUM>. The manner in which the anti-defeat impact protection mechanism <NUM> prevents such unwanted unlocking will become evident as the discussion progresses.

Referring now to <FIG>, there is provided an illustration showing the pin (or tack) <NUM> removably coupled to the security tag <NUM>. In this regard, it should be noted that the security tag <NUM> comprises a housing <NUM> which is at least partially hollow. The housing <NUM> can be formed from a rigid or semi-rigid material, such as plastic. The housing <NUM> can be formed of a plurality of parts 418a, 418b, 418c as shown in <FIG>. The housing <NUM> has a recessed hole <NUM> formed therein into which the pin (or tack) <NUM> is inserted.

The pin (or tack) <NUM> comprises a head <NUM> and a shaft <NUM>. The shaft <NUM> is inserted into the recessed hole <NUM> formed in the housing <NUM>. The shaft <NUM> is held in position within the recessed hole <NUM> via the magnetic lock mechanism <NUM>, which is mounted inside the housing <NUM>. As noted above, the magnetic lock mechanism <NUM> comprises a plunger <NUM> and a latch <NUM>. The magnetic lock mechanism <NUM> is in its locked position in <FIG>. In this locked positon, the plunger <NUM> is in engagement with the latch <NUM> so as to removably couple the pin (or tack) <NUM> to the security tag <NUM>.

The plunger <NUM> is actuated by or otherwise responsive to a magnetic field applied to the security tag <NUM>. When actuated by the magnetic field, the plunger <NUM> moves in a direction <NUM> along axis <NUM> within a guide channel <NUM>. In effect, the plunger <NUM> disengages the latch <NUM>. The magnetic lock mechanism <NUM> is in its unlocked position (not shown) when the plunger <NUM> no longer engages the latch <NUM>.

The plunger <NUM> moves in direction <NUM> within guide channel <NUM> when application of the magnetic field is discontinued. In this regard, it should be understood that the plunger <NUM> is resiliently biased in direction <NUM> by a resilient member <NUM> disposed along an elongate length of the plunger <NUM>. Resilient member can include, but is not limited to a, spring. In the spring scenario, resilient member <NUM> is normally in an uncompressed state as shown in <FIG>. When the plunger moves in direction <NUM>, the plunger <NUM> causes the resilient member <NUM> to be compressed (not shown in <FIG>). Thus, when the magnetic field is no longer applied to the security tag <NUM>, the resilient member <NUM> transitions to its uncompressed state whereby the plunger <NUM> is automatically caused to return to engagement with the latch <NUM>.

The anti-defeat impact protection mechanism <NUM> comprises an impulse mass <NUM> and an impulse spring <NUM>. The impulse mass and/or spring can be formed of metal. These impulse components <NUM>, <NUM> are tuned to allow the plunger <NUM> to disengage the latch <NUM> when the magnetic field is applied thereto, and prevent the plunger's <NUM> disengagement from the latch <NUM> as a result of an impact force being applied to the security tag <NUM>. In this regard, the impulse mass <NUM> is in contact with an end <NUM> of the plunger <NUM>, and disposed between the plunger <NUM> and the impulse spring <NUM>. In some scenarios, the impulse mass <NUM> has an aperture (not shown in <FIG>) formed therein into which a portion of plunger end <NUM> is inserted. A structure <NUM> is provided within which the impulse mass <NUM> and an impulse spring <NUM> are disposed. Both components <NUM>, <NUM> are able to move in opposing directions <NUM>, <NUM> within the structure <NUM>, but are unable to move in opposing directions <NUM>, <NUM> within structure <NUM>.

When an impact force is applied to the security tag <NUM>, the impulse mass <NUM> moves in direction <NUM>, whereby the impulse spring <NUM> is compressed. The impulse spring <NUM> then oscillates for a brief period of time and returns to its uncompressed state shown in <FIG>. Consequently, the anti-defeat impact protection mechanism <NUM> absorbs the shock caused by the impact force, and prevents the plunger <NUM> from disengaging the latch <NUM>. More specifically, the impulse mass <NUM> transfers the image force towards the latch <NUM>, thereby biasing the magnetic lock mechanism <NUM> into the locked position shown in <FIG>. As a result, the magnetic lock mechanism <NUM> does not unlock or unlatch. Therefore, the anti-defeat impact protection mechanism <NUM> serves to utilize the destructive force applied to the security tag <NUM> to more securely lock the pin <NUM> within the security tag housing <NUM>.

A magnetostrictive active EAS element <NUM> and a bias magnet <NUM> are optionally also disposed within the housing <NUM>. These components <NUM>, <NUM> may be the same as or similar to that disclosed in <CIT>. In some scenarios, the resonant frequency of components <NUM>, <NUM> is the same as the frequency at which the EAS system (e.g., EAS system <NUM> of <FIG>) operates (e.g., <NUM>). Additionally, the EAS element <NUM> is formed from thin, ribbon-shaped strips of substantially completely amorphous metal-metalloid alloy. The bias magnet <NUM> is formed from a rigid or semi-rigid ferromagnetic material. Embodiments are not limited to the particulars of these scenarios.

During operation, antenna pedestals (e.g., antenna pedestals <NUM>, <NUM> of <FIG>) of an EAS system (e.g., EAS system <NUM> of <FIG>) emit periodic tonal bursts at a particular frequency (e.g., <NUM>) that is the same as the resonance frequency of the amorphous strips (i.e., the EAS interrogation signal). This causes the strips to vibrate longitudinally by magnetostriction, and to continue to oscillate after the burst is over. The vibration causes a change in magnetism in the amorphous strips, which induces an AC voltage in an antenna structure (not shown in <FIG>). The antenna structure (not shown in <FIG>) converts the AC voltage into a radio wave. If the radio wave meets the required parameters (correct frequency, repetition, etc.), the alarm is activated.

Referring now to <FIG>, there are provided illustrations that are useful for understanding how the magnetic lock mechanism <NUM> operates without the anti-defeat impact protection mechanism <NUM> when an impact force is applied to security tag <NUM>, and how the magnetic lock mechanism <NUM> operates with the anti-defeat impact protection mechanism <NUM> when an impact force is applied to security tag <NUM>.

Referring now to <FIG>, an illustration is provided showing magnetic lock mechanism <NUM> in a locked or latched position. In the locked or latched position, the plunger <NUM> is in engagement with a latch <NUM>. The resilient member <NUM> is in an uncompressed state.

Referring now to <FIG>, an illustration is provided showing an application of an impact force <NUM> to the magnetic lock mechanism <NUM>. As a result of this impact force <NUM>, the plunger <NUM> moves in direction <NUM> as shown in <FIG>, whereby a flange <NUM> of the plunger <NUM> causes compression of the resilient member <NUM> and the plunger <NUM> disengages the latch <NUM>. Consequently, the magnetic lock mechanism <NUM> is undesirably defeated as a result of the impact force <NUM>. The anti-defeat impact protection mechanism <NUM> is provided to prevent such a defeat of the magnetic lock mechanism <NUM>.

Referring now to <FIG>, there is provided an illustration showing the magnetic lock mechanism <NUM> in a locked or latched position. In the locked or latched position, the plunger <NUM> is in engagement with a latch <NUM>. The resilient member <NUM> is in an uncompressed state. The resilient member <NUM> of the anti-defeat impact protection mechanism <NUM> is also in an uncompressed state, and the impulse mass <NUM> is at a first location relative to the latch <NUM>.

Referring now to <FIG>, an illustration is provided showing an application of an impact force <NUM> to the magnetic lock mechanism <NUM> and the anti-defeat impact protection mechanism <NUM>. As a result of this impact force <NUM>, the plunger <NUM> moves in direction <NUM> as shown in <FIG>, whereby a flange <NUM> of the plunger <NUM> causes compression of the resilient member <NUM> and the impulse mass <NUM> causes compression of impulse spring <NUM> as shown in <FIG>. The impulse spring <NUM> absorbs energy during its compression, oscillates for a brief period of time, and then releases the energy while providing a reactionary impulse force in direction <NUM> as it returns to its uncompressed state. In effect, the impulse spring <NUM> resiliently biases the impulse mass <NUM> in direction <NUM> as shown in <FIG>. The resiliently biased impulse mass <NUM> applies a pushing force on the plunger <NUM>, whereby the plunger <NUM> is caused to travel in direction <NUM> toward latch <NUM>. Notably, the plunger <NUM> never disengages the latch <NUM> as a result of the impact force's application to the security tag <NUM>.

Referring now to <FIG>, there are provided illustrations that are useful for understanding how the magnetic lock mechanism <NUM> operates and the anti-defeat impact protection mechanism <NUM> operate when a magnetic field is applied to security tag <NUM> during a detachment process.

Referring now to <FIG>, an illustration is provided showing an application of a magnetic field <NUM> to the anti-defeat impact protection mechanism <NUM> and the magnetic lock mechanism <NUM>. As a result of the magnetic field <NUM>, the impulse mass <NUM> and plunger <NUM> are attracted towards the magnetic field source. Accordingly, the impulse mass <NUM> and plunger <NUM> travel in direction <NUM> as shown in <FIG>, whereby the impulse mass <NUM> travels to a second location relative to the latch <NUM> and the plunger <NUM> disengages the latch <NUM> as shown in <FIG>. Notably, the anti-defeat structure allows the plunger <NUM> to travel a first distance <NUM> in a direction away from the latch <NUM> when the magnetic field <NUM> is being applied to the security tag <NUM> that is greater than a second distance <NUM> in the same direction that the anti-defeat structure allows the plunger <NUM> to travel when the impact force <NUM> is being applied to the security tag <NUM>. When application of the magnetic field <NUM> is discontinued, the anti-defeat impact protection mechanism <NUM> and the magnetic lock mechanism <NUM> return to their positions shown in <FIG>.

Referring now to <FIG>, there is provided a flow diagram of an illustrative method <NUM> for operating a security tag (e.g., security tag <NUM> of <FIG>). Method <NUM> begins with <NUM> and continues with <NUM> where a plunger (e.g., plunger <NUM> of <FIG>) of the security tag is caused to engage a latch (e.g., latch <NUM> of <FIG>) of the security tag. Next in <NUM>, an anti-defeat structure (e.g., anti-defeat impact protection mechanism <NUM> of <FIG>) of the security tag prevents a disengagement between the plunger and the latch when an impact force (e.g., impact force <NUM> of <FIG>) is applied to the security tag. The anti-defeat structure prevents the plunger's disengagement from the latch when an impact force is applied to the security tag by absorbing energy due to the impact force and releasing the energy to provide a reactionary impulse force in a direction (e.g., direction <NUM> of <FIG>) towards the latch. The reactionary impulse force causes the plunger to be pushed in a direction towards the latch prior to when the plunger travels out of the latch as a result of the impact force. In <NUM>, the anti-defeat structure allows the plunger to disengage the latch when a magnetic field (e.g., magnetic field <NUM> of <FIG>) is applied to the security tag. The anti-defeat structure allows the plunger's disengagement from the latch when the magnetic field is being applied to the security tag by absorbing energy while the plunger is being attracted to a magnetic field source (e.g., field source <NUM> of <FIG>). The anti-defeat structure allows the plunger to travel a first distance (e.g., distance <NUM> of <FIG>) in a direction away from the latch when the magnetic field is being applied to the security tag, and a second distance (e.g., distance <NUM> of <FIG>) in a direction away from the latch when the impact force is being applied to the security tag. The first distance is greater than the second distance. Subsequent to completing <NUM>, <NUM> is performed where method <NUM> ends or other actions are performed (e.g., return to <NUM>).

In some scenarios, the anti-defeat structure comprises an impact mass that is resiliently biased towards the plunger by an impact spring. The impact mass is disposed between the plunger and the impact spring, and is in contact with the plunger at all times. The impact spring is in a compressed state when the energy is being absorbed by the anti-defeat structure, and transitions from the compressed state to an uncompressed state when the anti-defeat structure releases the energy. The impact spring causes the impact mass to apply a pushing force to the plunger as the energy is being released by the anti-defeat structure. The pushing force causes the plunger to travel towards the latch and remain engaged with the latch despite the application of the impact force.

As shown in <FIG>, the detaching unit <NUM> comprises a computing device <NUM>, an RF transceiver <NUM>, a power source <NUM> (e.g., AC mains), and a field source <NUM> (e.g., a coil). RF transceivers, power sources and field sources are well known in the art, and therefore will not be described in detail herein. Still, it should be noted that the computing device <NUM> controls when the RF transceiver <NUM> and power source <NUM> for performing all or some of the above-described methods for verifying a detachment of a security tag (e.g., security tag <NUM> of <FIG>) from an article.

Referring now to <FIG>, there is provided an illustration of an illustrative architecture for a computing device <NUM>. Computing device <NUM> may include more or less components than those shown in <FIG>. However, the components shown are sufficient to disclose an illustrative solution implementing the present solution. The hardware architecture of <FIG> represents one implementation of a representative computing device configured to provide an improved item return process, as described herein. As such, the computing device <NUM> of <FIG> implements at least a portion of the method(s) described herein.

Some or all components of the computing device <NUM> can be implemented as hardware, software and/or a combination of hardware and software. The hardware includes, but is not limited to, one or more electronic circuits. The electronic circuits can include, but are not limited to, passive components (e.g., resistors and capacitors) and/or active components (e.g., amplifiers and/or microprocessors). The passive and/or active components can be adapted to, arranged to and/or programmed to perform one or more of the methodologies, procedures, or functions described herein.

As shown in <FIG>, the computing device <NUM> comprises a user interface <NUM>, a Central Processing Unit ("CPU") <NUM>, a system bus <NUM>, a memory <NUM> connected to and accessible by other portions of computing device <NUM> through system bus <NUM>, a system interface <NUM>, and hardware entities <NUM> connected to system bus <NUM>. The user interface can include input devices and output devices, which facilitate user-software interactions for controlling operations of the computing device <NUM>. The input devices include, but are not limited, a physical and/or touch keyboard <NUM>. The input devices can be connected to the computing device <NUM> via a wired or wireless connection (e.g., a Bluetooth® connection). The output devices include, but are not limited to, a speaker <NUM>, a display <NUM>, and/or light emitting diodes <NUM>. System interface <NUM> is configured to facilitate wired or wireless communications to and from external devices (e.g., network nodes such as access points, etc.).

At least some of the hardware entities <NUM> perform actions involving access to and use of memory <NUM>, which can be a Radom Access Memory ("RAM"), a disk driver and/or a Compact Disc Read Only Memory ("CD-ROM"). Hardware entities <NUM> can include a disk drive unit <NUM> comprising a computer-readable storage medium <NUM> on which is stored one or more sets of instructions <NUM> (e.g., software code) configured to implement one or more of the methodologies, procedures, or functions described herein. The instructions <NUM> can also reside, completely or at least partially, within the memory <NUM> and/or within the CPU <NUM> during execution thereof by the computing device <NUM>. The memory <NUM> and the CPU <NUM> also can constitute machine-readable media. The term "machine-readable media", as used here, refers to a single medium or multiple media (e.g., a centralized or distributed database, and/or associated caches and servers) that store the one or more sets of instructions <NUM>. The term "machine-readable media", as used here, also refers to any medium that is capable of storing, encoding or carrying a set of instructions <NUM> for execution by the computing device <NUM> and that cause the computing device <NUM> to perform any one or more of the methodologies of the present invention.

Claim 1:
A method for operating a security tag (<NUM>), comprising:
- causing a plunger (<NUM>) of the security tag (<NUM>) to engage a latch (<NUM>) of the security tag (<NUM>), the latch (<NUM>) arranged in a housing (<NUM>) of the security tag (<NUM>) and adjacent to a pin channel (<NUM>) defined in the housing (<NUM>) and configured to removably receive a pin (<NUM>) along a pin channel axis;
- preventing, by an anti-defeat structure (<NUM>) of the security tag (<NUM>), a disengagement between the plunger (<NUM>) and the latch (<NUM>) when an impact force (<NUM>) is applied to the security tag (<NUM>); and
- allowing, by the anti-defeat structure (<NUM>), the plunger (<NUM>) to disengage the latch (<NUM>) when a magnetic field (<NUM>) is applied to the security tag (<NUM>),
characterized in that
the anti-defeat structure (<NUM>) comprises an impact mass (<NUM>) that is resiliently biased towards the plunger (<NUM>) by an impact spring (<NUM>), and wherein the anti-defeat structure (<NUM>) and the plunger (<NUM>) are movable in a direction (<NUM>, <NUM>) perpendicular to the pin channel axis.