Abstract:
An apparatus and method for radio frequency identification (RFID) tags provides RFID enabled metal tags that are of thicknesses limited only by the thickness of the RFID chip embedded therein. The metal can support variable information, and as such, may be printed economically in short runs by various metal printing techniques. The RFID chip in the tag is readable from two sides of the tag.

Description:
TECHNICAL FIELD 
       [0001]    The disclosed subject matter is directed to Radio Frequency Identification (RFID), and in particular to tags with RFID chips, and methods for making these tags. 
       BACKGROUND 
       [0002]    Radio Frequency Identification (RFID) is a technology that incorporates the use of electromagnetic or electrostatic coupling in the radio frequency (RF) portion of the electromagnetic spectrum to uniquely identify an object, animal, or person. RFID is coming into increasing use in industry as an alternative to bar codes. The advantage of RFID is that it does not require direct contact or line-of-sight scanning. An RFID system consists of three components: an antenna and transceiver (often combined into one reader) and a transponder (the tag or chip). The antenna uses radio frequency waves to transmit a signal that activates the transponder. When activated, the tag or chip transmits data back to the antenna. The data is used to notify a programmable logic controller of an identification or that an action should occur. 
         [0003]    Low-frequency RFID systems (30 KHz to 500 KHz) have short transmission ranges (generally less than six feet). High-frequency RFID systems (850 MHz to 950 MHz and 2.4 GHz to 2.5 GHz) offer longer transmission ranges (more than 90 feet). In general, the higher the frequency, the more expensive the system. 
         [0004]    Sling identification tags, also known as sling tags, are tags that are permanently affixed to slings, loops of material, such as chains, wire rope and wire mesh, that connect loads to lifting devices. The sling tag is required by ASME (American Society of Mechanical Engineers) B30.9 2006 and includes indicia indicating the size, grade, rated capacity and reach of the sling. Similarly, other identification tags are commonly used in numerous applications, such as placement on computers, appliances and the like. However, development of metal sling tags and other metal identification tags that used RFID has been slow. 
         [0005]    One presently available RFID enabled metal sling tag is from the Crosby Group Inc. of Tulsa Okla., as part of their QUIC-CHECK® Inspection and Identification System. These QUIC-CHECK® enabled metal tags are of a cast stainless steel and include an indented space in the tag for mounting an RFID chip. As a result of this indented space, the RFID chip is positioned in the tag such that it is open and exposed on only one side of the tag. The RFID chip rests within the indented space surrounded on one side and along its periphery by insulating spacers, to prevent chip to metal contacts, to avoid radio frequency interference. 
         [0006]    This structure presents drawbacks, as the RFID chip is only readable from one side of the tag, where it is open and exposed, as it is surrounded by metal on all other sides of the tag, the metal causing interference with the radio frequency waves, needed to read the chip. By being readable on only one side of the RFID chip, the RFID chip is not fully utilized, and not all desired information may be placeable on the RFID chip. Because these QUIC-CHECK® tags are cast, they are of thicknesses greater than the RFID chip, and their uses are limited, as due to their thickness, they are not usable for marking numerous articles. Moreover, these cast tags can not support variable information, other than being recast, an expensive process requiring new molds and tools every time there is a change in the information, or completely new information. 
       SUMMARY 
       [0007]    The apparatus and method of the disclosed subject matter are directed to RFID enabled metal tags that are of thicknesses limited only by the thickness of the RFID chip embedded therein. Accordingly, sheet metal may be used as the tag. This sheet metal can support variable information, and as such, may be printed economically in short runs by various metal printing techniques. The RFID chip in the tag is readable from two sides of the tag. The RFID chip is mounted in resin in an opening in the tag, the opening being of a shape with substantial surface area for creating a strong bond with the resin. Based on the method of manufacturing, insulating spacers are not needed between the RFID chip and the metal of the tag opening, as the spacing function is provided by the resin itself. 
         [0008]    An embodiment of the disclosed subject matter is directed to an identification tag. The tag includes a metal body including oppositely disposed first and second sides and an aperture in the body, extending through the body, the aperture including at least one inner edge. A device, that is responsive to electronic signals, for example radio frequency signals or radio waves, is positioned in the aperture by an adhesive material that fixes the device in position in the aperture and maintains the device from contacting the at least one inner edge of the aperture. The device is accessible to electronic signals on the oppositely disposed first and second sides of the body. Additionally, the thickness of the device corresponds substantially to the thickness of the metal body. The device may be, for example, a radio frequency identification (RFID) chip. The adhesive material may be any material that allows for the passage of electronic signals, such as radio waves and signals to pass through it, and may be for example, a resin. 
         [0009]    Another embodiment is directed to a method for making an identification tag. The method includes providing at least one metal body with upper and lower surfaces, and making an aperture in the at least one metal body, the aperture extending through the at least one metal body. A device, responsive to electronic signals, for example, a radio frequency identification chip, is placed within the aperture. The device is maintained in a position where it is generally coplanar with the upper and lower surfaces. The aperture is filled with material that allows for the passage of electronic signals therethrough to fasten the device in place such that the device is out of contact with the edges of the aperture and that the device is accessible to electronic signals on both sides of the at least one metal body. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0010]    Attention is now directed to the drawings, where like numerals or characters indicate corresponding or like components. In the drawings: 
           [0011]      FIG. 1  is a front perspective view of a tag of the disclosed subject matter; 
           [0012]      FIG. 2  is rear view of the tag of  FIG. 1 ; 
           [0013]      FIG. 3  is a rear view of the tag of  FIG. 2  with a cap over a portion of the tag; 
           [0014]      FIG. 4  is a diagram showing the tag of  FIG. 1  in an exemplary operation; 
           [0015]      FIG. 5  is a diagram showing a sheet from which the tags of  FIG. 1  are made; and 
           [0016]      FIGS. 6A ,  6 B,  7 A,  7 B and  8  are diagrams showing processing of the sheet of  FIG. 5  to make the tags of  FIG. 1 . 
       
    
    
     DETAILED DESCRIPTION 
       [0017]      FIGS. 1 and 2  show a tag  20  in accordance with the disclosed subject matter. The tag  20  includes an area for variable information (for example, indicia)  22  and an aperture  24  that supports an RFID chip  26  (for example, a transponder loaded with data including identification data, responsive to radio frequency signals). There may also be other openings  28  in the tag  20 .  FIG. 1  shows one side  20   a  of the tag  20 , while  FIG. 2  shows the opposite side  20   b  of the tag  20 . The tag  20  may be used in numerous applications where identification tags are used, including as a sling identification tag or sling tag. 
         [0018]    The RFID chip  26  is held in the aperture  24  (in a fixed position) by adhesive  32 , such as a resin or other suitable material, that is electrically nonconductive (insulating or noninsulating), and allows for the passage of electronic (electrical) signals, including radiofrequency signals, radio waves and the like, therethrough. The adhesive  32  also maintains the RFID chip  26  such that the edges of the chip  26  remain out of physical contact from the metal edges  34  of the aperture  24 . The aperture  24 , is for example, formed of a star shape, such as a twelve pointed star, as the edges  34  that form the star shape provide maximum surface area for the resin  32  to bond. As the aperture  24  is open at both sides  20   a,    20   b  of the tag  20 , the RFID chip  26  is accessible from both sides  20   a,    20   b  of the tag  20 , free of interference from the metal of the tag  20 . While an RFID chip  26  is shown any other device with information responsive to electronic signals is also permissible. 
         [0019]    The tag  20  is made of, for example, sheet stainless steel, aluminum or anodized aluminum flat, of thicknesses ranging from, for example, approximately 0.063 inches to 0.125 inches. These metals can be etched or printed on by standard techniques (e.g., screen printing, chemical and laser etching, and the like), in order that variable information may be placed onto the tag  20 , in the area  22 , on one or both sides  20   a,    20   b.    
         [0020]    The tag  20  may also include an attachable cap  36 , as shown in  FIG. 3 , to which attention is also directed, that frictionally fits onto the tag  20 . The cap  36  protects the RFID chip  26 , and can be permanently attached with adhesives or the like to the tag  20 . The cap  36  is made of a polymeric material, so as not to create interference with the RFID chip  26 . 
         [0021]      FIG. 4  shows a tag  20  in an exemplary load lifting operation. The tag  20  is attached to a metal wire rope sling  40 , as required by U.S. Federal Law, by a wire ring  41 . The tag  20 , in particular, the RFID chip  26  is accessible from both sides  20   a,    20   b  of the tag  20 , free of interference from the metal of the tag  20 . Accordingly, a first operator OP 1  with a Radiofrequency transceiver (and antenna) unit  42   a  can access the RFID chip  26  from a first side  20   a  of the tag  20 , while a second operator OP 2  with a Radiofrequency transceiver (an antenna) unit  42   b  can access the RFID chip  26  from a other or second side  20   b  of the tag  20   
         [0022]    Attention is now directed to  FIGS. 5-8  that detail an exemplary process for manufacturing the tag  20 . Initially, the process begins with a metal sheet  60 , such as a sheet of stainless steel. Variable information may now be placed onto the sheet, at one or both sides, by any of the aforementioned printing and/or etching processes or techniques detailed above. This information is placed in spaces corresponding to the area  22  between the aperture  24  and the opening  28 , in a finished tag  20 . 
         [0023]    In  FIG. 5 , a star-shaped aperture  24  is punched into the metal sheet  60 , and here, for example, another opening  28 , proximate to a corresponding star-shaped aperture  24 , is punched into the sheet  60 . The star shaped aperture  24  is, for example, a twelve pointed star, but stars or shapes of any other arrangements or straight and rounded segments, that provide additional surface area for adhesive bonding, are also suitable, as are completely circular or rounded apertures. The star-shaped apertures  24  and openings  28  are punched, for example, by a press, such as an Amada 33 Ton turret punch press. Variable information may also be placed onto sheet, at one or both sides, at this time, by any of the techniques detailed above. This information is, for example, placed in each space between the aperture  24  and the opening  28 , this space corresponding to the area  22  on the finished tag  20 . 
         [0024]    A protective backer or pre-mask  62  is applied to one side of the sheet  60  on a laminating machine  64 , as shown in  FIG. 6A . The backer  62  serves as a support for the adhesive  32  and the RFID chip  26 . The backer  62  also maintains the chip  26  as substantially coplanar with the surface of the sheet  60  (ultimately of the tag  20 ), serves to keep the adhesive  32  within the plane of the metal of the sheet  60 . The now backed sheet  60  is placed onto a work table  66 , as shown in  FIG. 6B . 
         [0025]    An RFID chip  26  is placed into each aperture  24  of the sheet  60 , on the backer  62 , spaced apart from the edges  34  of the aperture  24 . An adhesive  32 , for example, in the form of a resin, is applied over the chip  26  filling the aperture  24 , such that there is not any unfilled space between the chip  26  and the edges  34  of the aperture  24 , as shown in  FIG. 7A . The resin is, for example, a polyurethane resin, such as a Ultra Violet (UV) curable resin. One suitable UV curable resin is Dymax 9-20601. 
         [0026]    The resin is cured as the sheet of tags  60 ′ is moved through a UV dryer  70  on a conveyer  72 , as shown in  FIG. 7B . Two passes through the dryer  70  are made, one for each side of the sheet  60 . Prior to the second pass, the backer or premask  62  is removed. During the passes, dwell times may be less than one minute. The now cured resin is not completely hard, as it has some flexibility. 
         [0027]    The individual metal tags  20  with the embedded chips  26  are then punched by a press  76  from the sheet  60 ′, as shown in  FIG. 8 . The press  76  may be, for example, the aforementioned Amada  33  ton turret punch press. A cap  36  may then be placed onto the tag  20  over the aperture  24  and the RFID chip  26 . If desired, the cap  36  may be additionally secured to the tag  20  by adhesives, for example, adhesives free of metal or other materials that may cause interference with electronic signals, including radiofrequency signals, radio waves and the like. 
         [0028]    Variable information or additional variable information may now be placed onto sheet, at one or both sides, by any of the printing and/or etching processes or techniques detailed above. This information is placed in each space between the aperture  24  and the opening  28 , this space corresponding to the area  22  on the finished tag  20  (that may have been previously etched or printed, as detailed above). 
         [0029]    While preferred embodiments of the disclosed subject matter have been described, so as to enable one of skill in the art to practice the disclosed subject matter, the preceding description is intended to be exemplary only. It should not be used to limit the scope of the disclosed subject matter, which should be determined by reference to the following claims.