Abstract:
Plastic asset identification tags are described. The tags define an attachment feature by which the tag is attached to the asset. The tag also defines a cavity or slot in which an RFID transceiver is placed. Epoxy fills the remainder of the slot or cavity. The RFID transceiver is programmed to respond to interrogation by transmitting a unique identifier that is associated with the object to which the tag is attached. Additional information about the object may also be responsively transmitted, and in some embodiments that additional information is also written on the outside of the tag. Other tags seal the RFID transceiver within a pocket of flexible fabric-supported PVC.

Description:
REFERENCE TO RELATED APPLICATION 
     This application claims priority to U.S. Provisional Application No. 61/080,821, filed on Jul. 15, 2008 and International Application No. PCT/US2009/037150 filed on Mar. 13, 2009. The entireties of these applications are hereby incorporated by reference. 
    
    
     FIELD 
     Some embodiments disclosed herein relate to an identification tag. More specifically, some embodiments relate to a tag bearing data retrievable by radio frequency stimulation. 
     BACKGROUND 
     The United States Occupation Safety and Health Administration (OSHA) requires chains and certain heavy equipment used in industrial settings to carry an identifying tag. The tag is stamped or engraved with identifying information, such as a serial number, model number, and other characteristics. Standard descriptive and/or warning text is engraved, molded, or embossed in the tag. Such tags are often made of steel or other durable metal. 
     Unfortunately, these industrial identification tags often deform in the face of typical industrial use. For example, when a chain is dragged behind a vehicle over the road, run over, or struck against a metal structure, or even where it might be subjected to intentional stress such as shot peening, the tags on these chains are often deformed beyond recognition (certainly beyond accurate, useful reading of data on its surface). Then, in order to comply with regulations, the tag must be replaced before the chain or equipment is used again. 
     There is a need, therefore, for more durable tags from which the necessary information can be read even after exposure to sometimes extreme stresses in industrial environments. 
     In addition, maintenance and use of industrial tags requires regular checking for the presence and proper condition of the tags. There is, therefore, also a need for convenient methods for checking industrial tags for function and legibility. 
     SUMMARY 
     It is, therefore, an object of some forms of the invention to provide a more durable identification tag. 
     It is also an object of some forms of the invention to provide a tag for chains and heavy equipment in industrial settings, where the tag carries information that is readable without physically contacting the tag even after the tag is subjected to high stresses of industrial use. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of an identification tag according to a first embodiment. 
         FIG. 2  is a plan view of the embodiment of  FIG. 1 . 
         FIG. 3  is a perspective view of an identification tag according to a second embodiment. 
         FIG. 4  is a perspective view of an identification tag according to a third embodiment. 
         FIG. 5  is a plan view of an identification tag according to a fourth embodiment. 
         FIG. 6  is a perspective view of an identification tag according to the fourth embodiment as it is being affixed to an industrial lifting device. 
         FIG. 7  is a schematic view of a test configuration applied to an identification tag according to the fourth embodiment. 
     
    
    
     DESCRIPTION 
     For the purpose of promoting an understanding of the principles of the invention, reference will now be made to certain embodiments illustrated in the disclosure, and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the invention is thereby intended, such alterations and further modifications in the illustrated device and such further applications of the principles of the invention as illustrated therein being contemplated as would normally occur to one skilled in the art to which the invention relates. 
     Generally, one form of the present invention is a durable identification tag made of a flexible plastic material, and in which an RFID transceiver is embedded. The tag is applied to a chain, heavy equipment, or other uniquely identified object. Another form is a thin, flexible tag that includes a sealed pocket holding an RFID transceiver. This tag is sewn onto a sling, rope, or other device to facilitate management of that asset and data about that asset. 
     Turning now to the embodiment illustrated in  FIG. 1 , tag  100  includes an information-bearing surface  102 , through-hole  104 , RFID transponder  106 , and transponder embedding cavity  108 . Information-bearing region  102  is engraved with information about the item to which tag  100  is attached. In the illustrated embodiment, that object is a chain, and the displayed information includes the working load limit (WLL), serial number, size, grade, reach in feet and inches, and number of legs of the chain. In some applications, additional information about the chain, such as acquisition date and source, maintenance records, and the like, is maintained in separated paper and/or electronic records. In other embodiments, such additional information is encoded on the RFID transponder  106  instead of or in addition to the information engraved in information-bearing surface  102 . 
     RFID transponder  106  is positioned in transponder embedding cavity  108  as will be discussed further below. In the exemplary embodiment, the RFID transponder  106  is an INFOCHIP RFID chip manufactured and distributed by InfoChip Systems, Inc., of Wetaskiwin, Alberta, Canada. In other embodiments, alternative RFID transponders are used. For example, RFID transponder  106  in various embodiments is active, semi-passive, or passive. Various transponders will have an integrated antenna, an external antenna, or both. The data provided by the RFID transponder  106  in various embodiments is loaded into the transponder  106  before it is placed within tag  100 , after it is inserted into transponder receiving cavity  108 , or repeatedly over time by remote means as will be understood by those skilled in the art in view of the present disclosure. 
     Turning to  FIG. 2 , a plan view of tag  100  is presented, and will be referred to in a description of the fabrication of tag  100 . In this exemplary fabrication method, a sheet of plastic is prepared into rectangular sheets about 5 inches long, 1.5 inches wide, and 0.25 inch thick. The overall shape varies from one embodiment to another, but this embodiment includes rounded corners  114  and through hole  104 . A laser, such as model V460-60 produced by Universal Laser Systems Inc. of Scottsdale, Arizona, takes a computer-readable graphics file as input and generates the outer contour accordingly, including curves  114 . The laser also produces through hole  104  and engraves the identifying and characteristic information into information-bearing surface  102  as illustrated in  FIG. 1 . 
     Transponder embedding cavity  108  is then created in the end of tag  100 . In some embodiments, cavity  108  is created by a rotary bit, by laser, or by other methods that will occur to those skilled in the art based upon the present disclosure. Cavity  108  may be deep enough within the volume of tag  100  so that impact on the surface of tag  100  is unlikely to damage the RFID transponder  106 . 
     The remaining space in transceiver cavity  108  is then filled. Abundant options will occur to those skilled in the art in the selection of materials with which to fill that space, but one suitable example is a 2-part epoxy casting resin (RESINLAB EP 965 LVLX Black), available for example from Ellsworth Adhesives in Germantown, Wisconsin. Alternative filling materials include LOCTITE HYSOL E-30CL, RESINLAB EP 1046 FG or RESINLAB EP 1121, or 3M SCOTCH-WELD Structural Plastic Adhesive DP-8005, all available from Ellsworth Adhesives. The epoxy is inserted into cavity  108  after transponder  106 , then cures at room temperature for one hour to a semi-rigid polymer state. Various materials are selected for different use cases, considering void penetration, wetting and adhesion properties, void penetration, air release, and finish to a smooth, high-gloss surface. Other factors include resistance to water, acids, bases and most organic solvents, ensuring that the RFID transponder  106  is protected from many physical threats. Of course, other fill substances meet other design goals and will occur to those skilled in the art in light of the present disclosure. 
     In this exemplary embodiment, the body of tag  100  is fabricated from NYLATRON GS from DSM Engineering Plastic Products in Reading, Pennsylvania. Other embodiments are injection molded from DSM&#39;s STANYL TW363, or ZYTEL ST801AW NC010 from DuPont. Those skilled in the art will find PVC, acrylics, and other plastics suitable for various applications. 
     The tag  100  in this exemplary embodiment is UV-resistant and durable through high temperatures, sun exposure, water exposure, and other natural threats to its integrity. In this embodiment, after the fill substance in cavity  108  is set, the chip is encoded with information. In some embodiments, the information encoded into transponder  106  is precisely the data engraved in information-bearing surface  102 . In others, only the serial number is stored in transponder  106 , while in still others additional recordkeeping information is stored. 
     A second embodiment is shown in  FIG. 3 . In this variation, tag  200  includes information-bearing region  202  and through-holes  204 . Through-holes  204  enable the attachment of tag  200  to identified objects by mechanical looping. An RFID transponder is embedded in tag  200  in another transponder-placement region  208 , though neither an RFID transponder nor the transponder-placement region is shown in  FIG. 3 . 
       FIG. 4  illustrates another embodiment, suitable for situations when legible writing on the outside of the tag is not needed. In this embodiment, tag  300  comprises body  302 , which defines through-hole  304  and cavity  306 . Transceiver  308  is placed within cavity  306 , and the remainder of cavity  306  is filled with epoxy  310 . This embodiment can be made very small (relative to the size of RFID transceiver  308 ). 
       FIG. 5  illustrates another embodiment, tag  400 . In this embodiment, tag  400  is made primarily of  18 -pound, fabric-supported PVC sheets. Tail portion  402  in this embodiment merely provides a rectangular area that is useful for attachment to an object as will be discussed further in relation to  FIG. 6 , below. Head portion  404  includes a multi-layer pocket  406  in which RFID transceiver  408  is placed. After that placement, pocket  406  is RF-welded shut along closed path  410 . Other closure techniques may be used in alternative embodiments, as will occur to those skilled in the art in view of the present disclosure. As shown in these embodiments, the RF-weld along path  410  makes pocket  406  substantially waterproof. The data available through RFID transceiver  408  in this embodiment can be any of the options described in relation to the embodiments above, or others as will occur to those skilled in the art in view of this disclosure. 
       FIG. 6  illustrates one way in which tag  400  can be affixed to certain assets. In this illustration, object  420  is a part of the asset, such as a strap, rope, sling, cable, or the like. Capacity label  430  is wrapped around object  420  and over tag  400 , then is sewn along stitching line  440  using durable nylon thread or the like. The stitching crosses the edge of capacity tag  430  and upper portion  402  of tag  400 , thereby affixing both identification tag  400  and capacity tag  430  to object  420 . Conventional capacity tags  430  are of a dimension and quality that allows RFID transceiver  408  to be queried from a suitable distance. 
     Alternative Fabrication Technique 
     An alternative method for fabricating tags  100 ,  200 , and  300  involves injection molding techniques. This process begins with resin in pellet form and ultraviolet-resistant dye, each of which is dried using conventional techniques to remove moisture in advance of the injection molding process. In some embodiments, the resin and dye are dried to about 0.01% moisture, while in other embodiments, the threshold is set at some other value less than or equal to 0.05%. The plastic resin and dye are then blended and loaded into a hopper for screw injection molding. Of course, in other embodiments, other types of molding will be used as will occur to those skilled in the art in view of the present disclosure. 
     During the molding process, the dyed resin is injected into a die to form the tag body, including defining the slot, or cavity, and any text and/or symbols that are to appear on information-bearing surface  102 . The injection dies in this embodiment are water-cooled, and once the plastic is injected, the dies are cooled and the tag is ejected from the die. In other embodiments, multi-cavity dies are used to form multiple tags (having the same or different shapes and/or markings simultaneously). 
     The tags are then “seasoned” by exposure to greater levels of humidity until their moisture content reaches about 2.7%. In other embodiments, of course, other moisture content thresholds will be used, as will occur to those skilled in the art in view of this disclosure. RFID transceiver chips are then inserted into the slot that was molded into each tag, and the remainder of the slot is filled with epoxy. 
     Additional information to be added to information-bearing surface  102  can be written using hand stamping, vibratory etching, laser etching, or screen printing. Other methods of writing data on the outside of the tag so that it is visible and legible will occur to those skilled in the art in view of the present disclosure. 
     Testing 
     Tags made according to the first exemplary embodiment above have been put through a shot peening chamber  250  consecutive times, placed under a concrete block and jerked out 15 times, then run over with a forklift 5 times, and placed on a chain and dragged behind a vehicle on the highway for over 2 hours. The RFID transceiver in each tag still functioned as intended. 
     Another tag made according to the first exemplary embodiment above was exposed to 65,000 pounds of pressure asserted perpendicular to the large side that includes information-bearing surface  102 . Though the text on the tag was somewhat deformed, it was still legible (it was primarily just larger than it had been), and the RFID transceiver still worked. 
     As illustrated in  FIG. 7 , a tag  500  of the form illustrated in  FIGS. 5-6  was attached to an industrial-grade sling  510 , and a length-wise strain force F was imposed lengthwise on each end of the sling  510 . The point at which the tag  500  was affixed to the sling  510  was placed outside the bight  520  in the sling  510 , within the protective sheath of the sling  510  on the side opposite post  530 . A pulling force of 2F=45,000 pounds was applied, and the RFID transceiver  540  in tag  500  still functioned. 
     While the inventions have been illustrated and described in detail in the drawings and foregoing description, the same is to be considered as illustrative and not restrictive in character, it being understood that the preferred embodiment has been shown and described and that changes and modifications that come within the spirit of the invention are desired to be protected.