Patent Publication Number: US-8540831-B1

Title: Method of manufacturing a cell tag

Description:
TECHNICAL FIELD 
     The present invention relates to a method of manufacturing a cell tag, and more particularly, which reduces or eliminates the need for stitching so as to reduce labor required and which provides a strong bond at edges of symbols and characters of a call sign of the cell tag, to increase integrity and readability of the call sign. 
     BACKGROUND ART 
     Cell tags are carried at visible locations on the clothing or gear of military and tactical personnel, for identification purposes. Modern cell tags utilize materials that are luminescent and heat reflective so as to be visible under low light and darkness conditions. Known cell tags typically include a call sign comprising one or more identifying symbols and/or characters for identifying the wearer as friend and foe. Representative symbols can include but are not limited to, stars, hyphens, triangles, etc.; and representative characters can include, but are not limited to, alphanumeric or typographical characters such as numbers and letters, e.g., 0-9 and A-Z. 
     In combat and tactical environments, soldiers and law enforcement personnel often depend on the ability to recognize each other, including to account for the location of individual members of a unit or team, and to distinguish friend from foe. Under these conditions, misidentification can be dangerous, including so as to result in serious injury and death. Distances at which identifications are made can be up to several tens or even hundreds of meters or yards, and identification can be impeded by numerous factors, including, but not limited to, relative movement between the parties, e.g., one traveling in a vehicle, low light, darkness, dusty, foggy, or rainy conditions. 
     Some known cell tags are of a stitched or sewn together laminated construction, and include call signs having luminescent and/or infrared reflective symbols or characters displayed through apertures in the outer layer, the surrounding edge portions of which are stitched or sewn, which makes the cell tags labor intensive to make. Also, the stitching can fail or be damaged under severe usage conditions, e.g., be torn or lost, such that symbols and characters can be difficult or impossible to read correctly, which can result in difficult or mis-identification. 
     It is also known to laminate cell tags using heat activated adhesives between the layers, but it has been found that this can result in damage to luminescence materials used for low light and dark conditions. 
     Thus, what is sought is a manner of manufacturing a cell tag incorporating a call sign requiring less labor, which cell tag will be less susceptible to damage, and possible resultant difficulty and mis-identification in use, so as to overcome one or more of the shortcomings and limitations set forth above. 
     SUMMARY OF THE INVENTION 
     What is disclosed is a method of manufacturing a cell tag incorporating a call sign using less labor, and which is less susceptible to damage, and possible resultant difficulty and mis-identification in use, so as to overcome one or more of the shortcomings and limitations set forth above. 
     According to a preferred aspect of the invention, a method of manufacturing a cell tag having a call sign visible under low light and dark conditions, requires steps of: 
     providing a first sheet having a front surface, a back surface, and peripheral edge portions defining at least one aperture of a predetermined size through the first sheet comprising all or part of one or more symbols or characters of the call sign; 
     providing a second sheet having a front surface comprising one of a photoluminescence material and a thermal reflective material; and 
     fixedly attaching the back surface of the first sheet to the front surface of the second sheet using only an adhesive or adhesives selected from a group consisting of a contact adhesive, a pressure sensitive adhesive, and a reactive adhesive, closely about at least a substantial portion of the peripheral edge portions. 
     According to another preferred aspect of the invention, the second sheet includes peripheral edge portions defining at least one aperture therethrough marginally smaller than the size of the aperture or apertures through the first sheet and positioned and oriented so as to be visible within the aperture or apertures of the first sheet when the back surface of the first sheet is fixedly attached to the front surface of the second sheet. The method additionally includes fixedly attaching a third sheet to a back surface of the second sheet such that a front surface of the third sheet will be visible through the aperture or apertures of the second sheet, the front surface of the third sheet comprising another of the photoluminescence material and the thermal reflective material. 
     As an attendant advantage of the invention, the peripheral edges extending about and defining the respective symbol or symbols and/or character or characters of the call sign of the cell tag are securely attached to the underlying sheet, so as to be less susceptible to being torn therefrom during hard use in environments such as combat, tactical operations and the like, where visibility and identification to friendly forces is important. 
     Further, it has been found that at least some photoluminescence materials used in cell tags are susceptible to damage when exposed to temperatures above those typically required for setting heat activated adhesives, which temperatures are typically about 180 degrees F. Thus, when attaching at least the sheet including the photoluminescence materials, temperatures should not exceed that heat activation temperature, e.g., 180 degrees F. Here, it should be noted that this temperature will be a function of the heat sensitivity of the photoluminescence material used, which will likely be different for different materials, and thus the value given should be understood to be provided for the purposes of example only. 
     According to another preferred aspect of the invention, the thermal reflective material will comprise a material that reflects radiation within the infrared range, which is nominally wavelengths from the edge of visible red light at 0.74 micrometers (μm), and extending conventionally to 300 μm. A non-limiting exemplary suitable material can be those available that meet one or more U.S. military specifications, commercially referred to by the term “glint squares”, and can include the adhesive layer on the back surface thereof, e.g., with a peel off covering. According to another preferred aspect of the invention, the luminescence material can be, as a non-limiting example, those available that meet MIL-3891B Spec., and have a glow in the dark life of 10 to 24 hours after exposure to light for 10 minutes or so. 
     According to still another preferred aspect of the invention, the backmost surface of the cell tag will comprise or be covered with elements of one side of a hook and loop fastening system, most preferably the hook elements, for releasable attachment to the other elements of the fastening system, e.g., the pile loop side. 
     As still another preferred aspect of the invention, the abutting surfaces of the sheets of the cell tag will be adhered together. As an additional step, the outermost peripheral edge portions extending about and bounding the cell tag will be reinforced, such as by stitching, to further strengthen the tag. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of cell tag manufactured according to the invention, illustrating one manner of attachment to a representative garment via a hook and loop fastening system; 
         FIG. 2  is an enlarged perspective view of the cell tag of  FIG. 1 ; 
         FIG. 3  is a front perspective assembly view of the cell tag of  FIGS. 1 and 2 , illustrating steps of manufacture thereof; 
         FIG. 4  is a rear perspective assembly view showing elements of the cell tag of  FIGS. 1 ,  2  and  3 ; 
         FIG. 5  is a representative sectional view through the cell tag of  FIGS. 1-4 ; and 
         FIG. 6  is a perspective view of another embodiment of a cell tag of the invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring now to the drawings, in  FIGS. 1 through 6 , two representative embodiments of a cell tag, denoted by numerals  10  and  12 , respectively, are shown. In  FIG. 1 , cell tag  10  is shown being attached to a garment  14  which is a protective vest for wear by military and law enforcement personnel. For this purpose, cell tag  10  (and cell tag  12 ) has a back surface  16  comprising hooks of a hook and loop fastening system of well known construction. Hooks  18  are releasably securable in the well known manner to a pile fabric surface  20  comprising pile loops of the fastening system. Here, cell tag  10  has a generally flat, rectangular overall shape, but it should be noted that, alternatively, it can have a wide variety of shapes, and therefore is not limited to the rectangular shape shown. 
     Cell tag  10  has a front surface  22  that includes a call sign  24 , which is intended to provide a visual identifier of the wearer of a garment to which cell tag  10  is attached, such as garment  14  illustrated. In this regard, call sign  24  will typically comprise a series or code of symbols and/or characters, denoted individually by the numerals  26 , which can be for instance, selected shapes, such as triangles, dashes, etc., and/or alphanumerical characters such as Arabic numerals 0-9 and English alphabetical characters A-Z, Cyrillic letters, Greek letters, Hebrew letters, as well as others. 
     It will be desirable for call sign  24  to be visible under a wide variety of conditions, including daylight, cloudy, dusty, rainy, and particularly, low light and dark conditions. To facilitate visibility and identification particularly under ambient low light and dark conditions, the symbols and/or characters, herein sometimes referred to as just symbols or characters, are desirably luminescent. To facilitate visibility and identification under infrared light conditions, the symbols and/or characters are desirably infrared reflective. If the user is attired in camouflage, it will desirable for the cell tag to have an overall camouflage look, while still being usable for identification purposes. 
     To provide the above desired characteristics, cell tag  10  is manufactured using multiple sheets, each having one of the desired characteristics, laminated together. A first sheet  28  will be the front facing or outer portion of cell tag  10  and has a front surface  30  and a back surface  32 . First sheet  28  is preferably of a suitable material such as a woven nylon, and can be of any desired color, and/or include a camouflage or other pattern on front surface  30  if desired. First sheet  28  has a plurality of peripheral edge portions  34 , which can be laser or otherwise suitably cut through the material of that sheet, defining and bounding apertures  36  through first sheet  28 . An attendant advantage of laser cutting is that it fuses the endmost portions of the edge portions directly adjacent to the aperture so as to limit or eliminate unraveling and fraying that could impede identification. 
     Each of the apertures  36  has a shape of all or a portion of at least one symbol and/or character of a predetermined first size comprising all or a portion of call sign  24 . Here, as a non-limiting example, apertures  36  form the characters “L”, “D” and “2” composing a call sign “LD2”. A representative width dimension of the first size is denoted by the letter “X” in  FIG. 3 . 
     Cell tag  10  includes a second sheet  38  having a front surface  40  and a back surface  42 , and apertures  44  therethrough having the shape of all or a portion of the at least one symbol and/or character of first sheet  28  but of a predetermined second size marginally smaller than the first predetermined size of apertures  36 , as denoted by the equations “X−n” and “Y−n” in  FIG. 3 , the value “n” representing the marginal difference between the respective widths (X dimension) and heights (Y dimension) of the apertures  36  and  44 . Second sheet  38  can be of a polymer film material, and/or a woven fabric or the like. Apertures  44  can be produced in any suitable manner, such as by laser cutting or die cutting. 
     Front surface  40  of second sheet  38  has peripheral edge portions  46  bounding at least a substantial portion of apertures  44  therethrough, and at least peripheral edge portions  46  comprise a commercially available photoluminescence material  48  that will absorb light and glow in low light or dark conditions for several hours thereafter, such as those that meet MIL-3891B. In this regard, it can be observed that the visible peripheral edge portions  46  have a width equal to about one-half the marginal value “n”. As a non-limiting example, the photoluminescence material will have a white, ivory or light green appearance under daylight conditions, and will emit a light green glow under low light and dark conditions, sufficient for identification purposes. For convenience of manufacture, the photoluminescence material can comprise a film or layer that covers the entire surface of second sheet  38 , if desired, and can be coated with a suitable protective material such as a suitable clear polymer. 
     Cell tag  10  additionally includes a third sheet  50  which can be of a film and/or fabric material, having a front surface  52  of a thermal reflective material, which is preferably an infrared reflective material, denoted by numeral  54 . As a non-limiting example, thermal reflective material  54  can comprise a commercially available material that reflects radiation within the infrared range, which is nominally wavelengths from the edge of visible red light at 0.74 micrometers (μm), and extending conventionally to 300 μm. This material will have a black or dark appearance under daylight conditions, but will glow sufficiently when exposed to infrared radiation under low light or dark ambient light conditions for identification purposes. A non-limiting exemplary suitable material can be those available that meet one or more U.S. military specifications, commercially referred to by the term “glint squares”. 
     As best shown in  FIGS. 3 through 5 , the sheets of cell tag  10  are fixedly attached or laminated together. In this regard, at least back surface  32  of first sheet  28  is adhered to front surface  40  of second sheet  38  using only an adhesive or adhesives selected from the group consisting of a contact adhesive, a pressure sensitive adhesive, and a reactive adhesive, closely about at least a substantial portion of peripheral edge portions  46  of the second sheet, such that the peripheral edge portions  34  of the first sheet will bound peripheral edge portions  46  of the second sheet and the peripheral edge portions  46  of the second sheet, and importantly, the photoluminescence material  48  will outline and bound apertures  44  of the second sheet. Most preferably, the entire overlapping abutting portions of sheets  28  and  38  will be adhered together in this manner to provide secure attachment between the sheets and so as to fix the relation of the photoluminescence material in the apertures of the first sheet. 
     Front surface  52  of third sheet  50  will preferably be adhered in the same manner to back surface  42  of second sheet  38 , to securely attach the second and third sheets together, and such that infrared reflective material  54  will be viewable in apertures  44  of the second sheet and bounded and outlined by the photoluminescence material  48 . Back surface  16  of cell tag  10  including hooks  18  can comprise a fabric or film suitably attached to the back of third sheet  50  in a suitable manner, such as using the adhesives set forth above for secure attachment over the entire covered surface of the third sheet. Additionally, for security, the three layers of sheets  28 ,  38 , and  50  can be stitched together, as denoted by stitching  56  about the outer periphery of cell tag  10 , for strength. 
     In  FIG. 6  cell tag  12  is shown. Cell tag  12  differs from cell tag  10  in the use of only first sheet  28  with third sheet  50 , such that peripheral edge portions  34  of the first sheet bound and define apertures  36  defining call sign  24 , and so that infrared reflective material  54  is visible in apertures  36  to allow identification when infrared radiation is present. Cell tag  12  also includes hooks  18  for attachment to pile fabric surface  20  of a garment in the above described manner. Stitching about the outer edge of tag  12  can also be used if desired for strength enhancement. Alternatively, a sheet  38  including photoluminescence material  48  could be used instead of infrared reflective material  54  to provide identification under just low light and darkness conditions. 
     As an advantage, because stitching is not required about the individual symbols or characters of the call sign, labor is saved, yet adequate strength and durability is achieved, with reduced occurrence of ripping or detachment of adjacent regions of the cell tag and resultant identification problems that can occur. 
     As a preferred manner of manufacture, the adhesives used for attaching the sheets together comprise a layer  58  of an acrylic based pressure sensitive adhesive, adhered to the back surface  32 ,  42  of the sheet to be adhered, and covered by a protective film  60  which is removed when used. As a result, temperature activated adhesives is avoided, which can cause possible damage one or both of photoluminescence material  48  and infrared reflective material  54 , when activated, which can require application of heat to 300 degrees F. or so for thermosetting adhesives, and 180 degrees F. or so, for non-thermosetting adhesives. 
     Thus, there has been shown and described a novel method of manufacturing a cell tag, which overcomes many of the problems and shortcomings set forth above. It will be apparent, however, to those familiar in the art, that many changes, variations, modifications, and other uses and applications for the subject device are possible. All such changes, variations, modifications, and other uses and applications that do not depart from the spirit and scope of the invention are deemed to be covered by the invention which is limited only by the claims which follow.