Abstract:
A tamper-evident seal having dual, reusable catches and a seal element adapted lockably to engage either of the catches, the extent of this engagement being, furthermore, adjustable without thereby rendering the seal itself reusable, once it has been broken. The two catches may each bear an integrally-formed, clasp-like structure, which facilitates the attachment of the catches and, consequently, of the tamper-evident seal, to a variety of external devices. Both the seal and the catches have a generally squared-off design, which helps to reduce mold-making costs by adding a degree of freedom to the placement of the parting lines.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     U.S. patent application Ser. No. 09/369,350, now U.S. Pat. No. 6,109,673. 
    
    
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     Not Applicable 
     REFERENCE TO A MICROFICHE APPENDIX 
     Not Applicable 
     BACKGROUND OF THE INVENTION 
     This is a Continuation in Part of U.S. patent application Ser. No. 09/369,350 filed Aug. 6, 1999 now U.S. Pat. No. 6,109,673. The art in which the present invention resides thus is likewise broadly defined by tamper-evident seals that are at least in part reusable. 
     The present invention extends and amplifies the art disclosed in the parent application by offering improved adjustability, reduced cost of manufacture, and easier application to external devices. As before, in the parent application, the present invention has two, reusable catches, but now adds an engaging-element whose engagement-length is adjustable, yet which has, with respect to each catch, a unique, weakest point for that catch, so located as to prevent reuse of the engaging-element once it has been broken. 
     Security devices having dual catches, and further having engaging-elements whose engagement-length is individually adjustable at each catch are well known. A bilaterally symmetric device having two catches and two, adjustable-length, linear ratchets is taught by U.S. Pat. No. 4,910,831 to Bingold (1990). Bingold&#39;s device, however, does not provide weak points at which its respective linear ratchets sever preferentially from the overall device. The severing from Bingold&#39;s device of his linear ratchets would, in fact, destroy the utility of Bingold&#39;s device, because it is intended to function as a handcuff. 
     BRIEF SUMMARY OF THE INVENTION 
     The present invention provides an engaging-element, referred to in shorthand-manner as the “seal”, comprising a long mid-section and two linear ratchets, one each abutting the opposite ends of the mid-section, each linear ratchet in itself further comprising a plurality of abruptly shouldered sub-elements. The long mid-section and each of the two, linear ratchets further respectively comprise a pair of parallel side rails. The parallel side rails of each linear ratchet help to prevent the linear ratchet from breaking at any one of the several junctions of its successive, abruptly-shouldered sub-elements when stressed. 
     Taken together, the long mid-section and the two linear ratchets form the top portion of the engaging-element. In the present invention, this top portion has two, least cross-sectional areas, these being coincident with the junctions of the linear ratchets with the long mid-section. A tugging force applied to the seal&#39;s top portion at either end, such as a force tending to pull the catches of the present invention apart after the seal has been brought into lockable engagement with both catches, thus will sever one or the other of the linear ratchets in its entirety from the remainder of the seal, rather than severing one or the other of the linear ratchets internally, at one of the junctions between two of its adjacent, abruptly-shouldered sub-elements. 
     The greatest cross-section of the seal&#39;s mid-section orthogonal to its length is geometrically substantially similar to (it is H-shaped in the embodiment herein illustrated) to the greatest, parallel cross-section of either of the linear ratchets, and is furthermore not greater than this cross-section in either area or longest dimension. These cross-sectional relationships allow the mid-section to pass easily on its own through either catch. 
     Attached to the mid-section is an identification element which, as in the parent application, may be torn off by a twisting force applied substantially orthogonally to the force needed to sever either of the linear ratchets from the engaging-element. 
     The catches, in order to be reusable, are injection molded out of a rugged thermoplastic, such as nylon or polycarbonate. The engaging-element is injection molded out of a much weaker, more elastic material, polypropylene for example. 
     The engaging-element illustrated herein is bilaterally symmetric, although one of its linear ratchets might be made longer than the other, should such an asymmetry suit a particular purpose. 
     Each catch of the present invention bears an asymmetric, clasp-like feature that allows easy attachment of the catch to a variety of external devices. The present invention furthermore displays, if one may so speak, a generally square aesthetic, as opposed to the organic, rounded aesthetic of the parent invention. This squaring-off of elements can help to reduce mold-making costs, inasmuch as parting lines can now be positioned with one greater degree of freedom. 
     With the foregoing in mind, it is an important object of the present invention to offer a tamper-evident seal that is easily and bilaterally adjustable. 
     It is yet another object of the present invention to permit this adjustability and yet to prohibit the reuse of the engaging-element. 
     It is yet another object of the present invention to provide a tamper-evident seal having multiply-reusable catches that may be easily attached to a variety of external devices. 
     It is still a further object of the present invention to reduce mold-making costs. 
     These and yet further objects and advantages of the present invention will become apparent from a consideration of the following, detailed specification, drawings, and appended claims. 
    
    
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING 
     Referring to the drawings, wherein like reference characters indicate like parts or elements throughout the several views, and in which solid arrowheads point to compound objects whose numbered resolution into constituent parts occurs when it is germane to the discussion: 
     FIG. 1 is an elevation front view of the preferred embodiment of the present invention, showing the elements thereof in locked engagement with one another. 
     FIG. 2 is an elevation front view of the bilaterally symmetric, central element of the embodiment shown in FIG.  1 . 
     FIG. 3 is a cross-section of the element shown in FIG. 2 taken along line  3 — 3  of FIG.  2  and enlarged in scale. 
     FIG. 4 is a cross-section of the element shown in FIG. 2 taken along line  4 — 4  of FIG.  2  and in the scale of FIG.  3 . 
     FIG. 5 is a front plan view of one of the two, like, catch elements of the embodiment shown in FIG. 1 taken along line  5 — 5  of FIG.  1  and omitting the element shown in FIG.  2  and drawn to the scale of FIGS. 3 and 4. 
     FIG. 6 is a cross-sectional view of the embodiment shown in FIG. 1 after one of the symmetric ends of the element shown in FIG. 2 has been severed and the catch element previously in engagement with that severed end has been omitted and taken along line  6 — 6  of FIG.  1  and drawn to the scale of FIG.  3 . 
     FIG. 7 shows the elements in FIG. 6 in the same scale and additionally includes two, schematic, human fingers. 
     FIG. 8 is a perspective view of one of the catch elements of the embodiment shown in FIG. 1 subsequent to that catch element&#39;s manufacture but prior to its use and drawn to the scale of FIG.  1 . 
     FIG. 9 is an enlarged view of the portion of FIG. 8 within dotted box  9 . 
     FIG. 10 is a perspective view of a device external to the present invention and to which it may be attached drawn to the scale of FIG.  8 . 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     FIG. 1 shows a tamper-evident seal comprising engaging-element  10  and two congruent, catch elements  20 . Engaging-element  10  comprises mid-section core  13  and mid-section bottom side rail  19  and mid-section top side rail  17 . Engaging-element  10  further comprises tear-off, identification element  111  having serial number  112 . ID element  111  is attached to mid-section bottom side rail  19  by perforation teeth  142  separated by perforation holes  141 . ID element  111  could very easily be attached by other means, such as a row of thin, staggered elements, as disclosed in FIG. 10 of the parent application. An abscission bead is formed in either case that allows tag  111  easily to be torn off mid-section bottom side rail  19 . 
     Each catch element  20  has catch housing  21  and top and bottom arms  23   t  and  23   b,  respectively, which, in the embodiment of the invention shown in FIG. 1, lend to catches  20  substantially the appearance of square-cross section chain links. Arms  23   t  and  23   b  meet at junction  25 . The plane that defines FIG. 6, located by line  6 — 6  of FIG. 1, cuts catch housings  21  through their joint midline, which is also the midline of mid-section core  13 . Junction  25 , however, lies to one side of line  6 — 6 . That is, arms  23   t  and  23   b  are asymmetric. 
     At the far, that is opposite, ends of the top portion of engaging-element  10  are tapered tongues  12 , which guide the insertion of engaging-element  10  into the catches  20 . 
     FIG. 2 reveals that engaging-element  10  additionally comprises tapered ends  15  (preview FIG. 6) of mid-section core  13 . Tapered ends  15 , together with mid-section top side rail  17 , mid-section bottom side rail  19 , and mid-section core  13  are the mid-section of engaging-element  10 . Small notches  18   t  are cut away from mid-section top side rail  17 , two notches at either end (preview FIG.  4 ), and similar, small notches  18   b  are cut away from mid-section bottom side rail  19 , again two at either end. Side rails  17  and  19  being parallel and in registry and equally long, the pair of notches  18   t  at either mid-section end is in planar registry with the pair of notches  18   b  (preview FIG. 4) at that same end. 
     Abutting each end of mid-section top side rail  17  is a ratchet top side rail  16   t,  and abutting each end of mid-section bottom side rail  19  is a ratchet bottom side rail  16   b  congruent to rail  16   t  in registry above it (preview FIG.  3 ). Between, and integrally formed with, rails  16   t  and  16   b  is a set of abruptly-shouldered sub-elements, here of equal length (preview FIG. 6) and three in number, namely sub-elements  14   a,    14   b,  and  14   c.  For the embodiment of the present invention herein illustrated, a linear ratchet is thus understood to consist of one set of abruptly-shouldered sub-elements  14   a,    14   b,  and  14   c,  plus their adjacent top and bottom side rails  16   t  and  16   b,  plus tongue  12 , in which the sub-element  14   c  terminates. Engaging-element  10 , being bilaterally symmetric, has two such linear ratchets. 
     When engaging-element  10  is not in engagement with either of the catches  20  it is non-contiguous with both of them, that is, it may be carried about as a separate object, independent of the catches. 
     FIG. 3 is a cross-section taken ever so slightly to one side of (to the right of in FIG. 2) a junction between two adjacent, abruptly-shouldered sub-elements of a linear ratchet, here, for specificity&#39;s sake, between  14   c  and  14   b  of the left ratchet. Of sub-element  14   c  we see only its exposed, symmetric surfaces  114   c,  and of sub-element  14   b  we see only its smallest cross-section. Surfaces  114   c  together define the greatest width of abruptly-shouldered sub-element  14   c.  Sub-element  14   b  has corresponding surfaces  114   b  (illustrated in FIG.  6 ), each identical in area to surfaces  114   c.  Top side rail  16   t  and bottom side rail  16   b  lend rigidity to the junction of adjacent sub-elements  14   c  and  14   b,  that is, the rails keep the junction from being unduly fragile. 
     FIG. 4 is a cross-section taken ever so slightly to one side of (to the right of in FIG. 2) a junction of one of the tapered ends  15  (the leftmost in FIG. 2) with the adjacent, abruptly shouldered sub-element  14   a.  Of  14   a  we see only its exposed, symmetric surfaces  114   a,  which together define the greatest width of abruptly-shouldered sub-element  14   a.  Although this greatest width of  14   a  is identical to the greatest width of sub-elements  14   a  and  14   b,  surfaces  114   a  are seen to be significantly greater in area than surfaces  114   c  in FIG.  3 . Another way of saying this is that tapered end  15  has a smaller, least cross-section than any of the sub-elements  14   a,    14   b,  or  14   c,  and that mid-section top and bottom side rails  17  and  19  have a combined cross-section that is smaller than the combined cross-section of ratchet top and bottom side rails  16   t  and  16   b.  The cross-section shown in FIG. 4 thus has the smallest cross-sectional area of any cross-section taken orthogonally to the side rails of engaging-element  10  (compare the hatched portion of FIG. 4 to the hatched portion of FIG.  3 ). These cross-sectional relations insure that the linear ratchets will break off in their entirety from the mid-section of engaging-element  10  when engaging-element  10  is lockably engaged with both catches  20  and a force is applied to the catches  20  tending to pull them apart. To further facilitate this breakage under stress of engaging-element  10  at the junction shown in FIG. 4, a pair of top notches  18   t  and a pair of bottom notches  18   b  are located at this junction as well. 
     FIG. 5 is a view through “H-shaped” aperture  24  of catch housing  21 . Bilaterally symmetrically placed within aperture  24  are resilient, converging elements  22 , typically called fingers, that allow the passage of either of the linear ratchets past them in one direction only. In particular, any of the abruptly-shouldered elements (in the embodiment of the present invention herein illustrated any of the sub-elements  14   a,    14   b,  or  14   c  of either the left, or of the right, linear ratchet) may pass through aperture  24  and past fingers  22  (preview FIG.  6 ). However, following a particular sub-element&#39;s passage past fingers  22 , fingers  22  spring back behind that sub-element&#39;s abrupt shoulder, thus preventing movement of the linear ratchet as a whole in the opposite direction. What would the world come to without resiliency? 
     FIG. 6 depicts the left linear ratchet in locked engagement with catch  20 . Sub-element  14   b  has passed resilient fingers  22 , which in turn have sprung back behind it so that they now abut surfaces  114   b,  thus preventing movement of sub-element  14   b,  and hence of the left linear ratchet, out of catch  20 , that is, to the right in the figure. In FIG. 6, the right linear ratchet is missing, having in its entirety been broken off engaging-element  10  by some force earlier applied to the catches  20 . Mid-section core  13  is revealed to be appreciably less wide than mid-section bottom side rail  19 , and therefore to be appreciably narrower than the greatest width of any of the abruptly-shouldered sub-elements  14   a,    14   b,  or  14   c.  Tapered ends  15  of core  13  are equal to it in maximum width. 
     FIG. 7 shows the remainder of engaging-element  10  shown in FIG. 6 but now subsequent to the further removal of identification element  111 . Human fingers  50  and  51  urge and guide this reduced remainder of engaging-element  10  through catch  20 . The width of core  13  being appreciably narrower than the greatest width of any of the abruptly-shouldered sub-elements  14   a,    14   b,  or  14   c,  the mid-section of engaging-element  10  easily passes between fingers  22  and thus easily on and through catch  20 . Finger  51  presses a bit on left linear ratchet LLR so as to guide tongue  12  past bottom rear leg  232   b  (preview FIG. 8) of arm  23   b.  In so doing, the material of the reduced remainder of engaging-element  10  may be stressed just sufficiently to cause the junction of ratchet LLR with the seal&#39;s mid-section to tear a bit at one of the bottom notches  18   b,  as shown in the figure. Whether such a tearing actually occurs or whether just a stretching occurs will depend on the plasticity of the seal and on the depth of notches  18   b.    
     FIG. 8 shows one of the catches  20  after its manufacture but prior to its actual use. Arms  23   t  and  23   b  are each joined to catch housing  21  and are seen to be spaced apart just sufficiently that they do not touch. The angle between them in FIG. 8 is 3°. Top arm  23   t  comprises top, lengthwise leg  231   t  and top, short, rear leg  232   t.  Bottom arm  23   b  comprises bottom, lengthwise leg  231   b  and bottom, long, rear leg  232   b.  Arms  23   t  and  23   b  are thus asymmetric. 
     FIG. 9 shows in detail the clasp-like mechanism of catch  20 . Bottom long rear leg  232   b  terminates in a stepped, serrated end, of which a congruent copy, rotated 180°, forms the adjacent end of top short rear leg  232   t.  Arms  23   t  and  23   b,  when pressed together forcefully enough to induce a temporary, plastic deformation or their stepped, serrated ends, will interlock. The stepped, serrated end of leg  232   b  has parallel flat faces  251   b  and  255   b,  orthogonal to leg  232   b.  Oblique, flat face  252   b  intersects face  251   b,  and oblique, flat face  254   b,  parallel to face  252   b,  intersects face  255   b.  Oblique faces  252   b  and  254   b  extend just past, and on opposite sides of, the mid-line of leg  232   b,  and are connected by flat face  253   b,  parallel to faces  251   b  and  255   b.  All of these five, flat faces are exactly repeated at the end of leg  232   t  and thus are numbered identically, with the suffix b however being replaced by the suffix t. When arms  23   t  and  23   b  are pressed together, faces  252   t  and  252   b  slide along upon one another, all the while loading stress into arms  23   t  and  23   b,  until the moment when the edges at the intersections of faces  252   t  and  252   b  with faces  253   t  and  253   b,  respectively, just slide by each other, whereupon the induced stress is partly relieved as the arms&#39; stepped, serrated, clasp-like ends snap into interlocking engagement. Some residual, deformation-stress, a result of the arms&#39; rotation, each through an angle of about 1.5° from its original, cast position, will remain in arms  23   t  and  23   b,  as well as in catch housing  21 . This residual stress stays in the structure, much like the static stress contained within arches holding up an aqueduct. A drop of capillary cement on the junction of arms  23   t  and  23   b  will join them essentially permanently (this works quite well for polycarbonate), or they might, for example, be near-field, ultrasonically welded (this works well for nylon and the polycarbonate). 
     FIG. 10 shows external device  60 , here a metal stamping in the form of a flat staple, to which catch  20  may easily be connected. Device  60  has flat staple  61 , which extends above surface  62  of base plate  63 . Holes  64  allow device  60  to be mounted, as by rivets, to some other device, for example a storage-compartment door. Catch  20  is just able to rotate freely within flat staple  61 . 
     Catch  20 , because its rear legs are of unequal length, can be slipped more easily, that is, with less deformation, over staple  61  than it could be were its legs  232   t  and  232   b  equal in length. Furthermore, if, instead of a flat staple, a round-cross section chain link were to be embraced by catch  20 , and if catch  20  itself, instead of resembling a square chain link resembled a more oval chain link, yet still had asymmetric arms, then a pulling force applied to catch  20  would be transmitted to the junction of those arms not nearly as directly as it would be were those arms bilaterally symmetric, that is, were their junction to lie on the mid-line of catch  20 . Asymmetry in the more-rounded case safeguards the junction. 
     The present invention might be optionally supplied with a set of engaging-elements having more than one color. Security may be enhanced inexpensively through impromptu, seal-color changes. 
     Inasmuch as modifications and alterations apparent to one skilled in the art may be made in the herein described embodiment of the present invention without departing from the scope and spirit thereof, it is intended that all matter contained herein be interpreted in an illustrative, and not in a limiting, sense with respect to the invention claimed in the following claims and equivalents thereto.