SECURITY SEAL OF THE PADLOCK TYPE

Abstract: A seal of the type resembling a padlock and comprising a plastic housing having a pair of apertures for receiving a shackle of the type formed of a U-shaped piece of wire with reversely bent end portions, the extreme ends of which are intended to dig into the internal surface of the walls of the body apertures to prevent retraction of the shackle. To prevent release of the shackle by a tool slid into the aperture alongside the shackle, which might be able to squeeze the reversely bent portion to a sharper bend and thereby allow retraction of said end from the aperture without the extreme end digging into the aperture wall, the shackle is provided with a bent portion which is shaped and positioned to enter the aperture when the seal is closed and extend conpletely across the width of the aperture. To prevent straightening of the bent portion to reduce its width to allow a tool to be inserted into the aperture alongside the bent portion, the extreme ends of the aperture are sharpened and the seal body is provided with a recess therein which is so positioned that when any appreciable tension is applied to the shackle, the sharpened ends pierce through the aperture wall into the recess, giving evidence of tampering.

Description: BACKGROUND OF THE INVENTION In U.S. patents 3,375,033, 3,485,521 and 4,278,281, there are disclosed seals of the padlock type in which the body is formed of sysnthetic organic plastic, with a pair of internal apertures opening to one end of the body, and having a shackle formed of a piece of U-shaped wire having legs with reversely bent end portions. The end portions, when inserted into the body apertures, are intended to be locked therein against retraction by the fact that the reversely bent end portions are maintained in a flexed condition so that the extreme end portions dig into a wall of the aperture and prevents removal. However, it has been considered possible that under favorable circumstances unauthorized persons might be able to defeat the seal by inserting a suitable tool into one of the apertures alongside the shackle leg, and manipulating the tool to force the shackle leg sideways to collapse the reversely bent end, so that the leg could then be removed from the aperture without the extreme end of the reversely bent portion digging into engagement with the aperture wall. A prior art shackle that is of interest is disclosed in US-A-3 838 878. It discloses wire shackle for assembly into a seal body of the type having a pair spaced rectangle apertures, said wire having a diameter which is substantially the same as the width of the apertures into which it is to be assembled and being generally U-shaped forming a pair of legs for entering one into each of said apertures. Each of the legs has a reversely bent end portion which is dimensioned to be flexed towards its associated leg when inserted into the aperture. The extreme end of said reversely bent portion is sufficiently sharp to penetrate the material of the seal body if attempts are made to pull it out of the seal body once it has been installed therein. Each leg has an obliquely extending portion that traverses across the cross section of the aperture into which it extends and thereafter it continues along the wall surface with which it is then in engagement before reaching said reversely bent end portion. A further prior art is that disclosed in EP-A-0 211 499, published 8.4.1987, in which the seal body has a pair of spaced rectangular apertures for receiving a U-shaped wire shackle defining two legs, one leg for each of said spaced apertures. Each leg has a reversely bent portion at its free end, the resulting terminal end of each reversely bent portion being such than it is inclined towards a central land portion in the sealing body that serves to divide the sealing body into said pair of rectangular apertures. The central land portion is formed on each side with a shoulder with which, when said arms have been fully inserted into the seal body, said terminal ends of the two legs engage to prevent the wire shackle from being withdrawn from the seal body. The seal body has two entrance openings, one for each shackle leg, and each of these openings is of a length sufficient to allow said reversely bent portion of the related shackle leg to pass therethrough. Once the shackle legs have passed through said openings the arrangement is such that the way is clear for a tool to be inserted into said openings and for the tool to enter the seal body until it is in engagement with the inner root surface of a reversely bent portion of a shackle leg. To prevent such tools from then being used to force said reversely bent portions away from said shoulders and thus releasing the shackle, the seal body has special built up surfaces on its inside to block any such release movement of a reversely bent end portion. The present invention is as defined in the accompanying claims. In Claim 1 the features in the pre-characterizing part can be found in US-A-3 838 878, the nearest prior art. SUMMARY OF THE INVENTION This invention provides a security seal of the padlock type, in which a plastic body is provided with, in one embodiment, a pair of internal cavities opening to one end of the body, and a wire shackle having legs with reverse bent end portions for locking the legs in the shackle cavities. To prevent the insertion of a tool into the cavity to force the leg sideways to bend the reversely bent end closer to the leg, each shackle leg is provided with a bend forming a tool blocking portion which extends completely across the cavity, said bend being positioned on the legs to become positioned just below the surface of the housing when the shackle is fully assembled and having a portion extending substantially perpendicular from the leg. Such bend might be straightened by pulling on the shackle leg with a pair of pliers or the like, after which such a tool could be inserted. To provide evidence of such an attack on the seal, the extreme ends of the reversely bent portion may be sharpened, and the seal body may be provided with a groove so positioned that when a shackle leg is pulled in an attempt to straighten the wire, the ends of the reversely bent portions pierce the plastic body and extend into the groove, where they are clearly visible. BRIEF DESCRIPTION OF THE FIGURES OF THE DRAWING Figure 1 is a view in elevation of a seal embodying the features of the invention, in the condition as received by the user. Figure 2 is a view of the seal of Figure 1, partly in section to show the internal cavities of the seal body. Figure 3 is a view in elevation of the seal of Figures 1 and 2 in which the shackle has been pushed into the body into the locking position. Figure 4 is a view in section taken on line 4-4 of Figure 3. Figure 5 is a view in section taken on line 5-5 of Figure 3. Figure 6 is a view of the assembled seal of Figure 3, after a shackle leg has been pulled to partially straighten the bent portion of the leg. DESCRIPTION OF THE ILLUSTRATED EMBODIMENT Referring to the drawing, there is illustrated a seal 10 of the padlock type, comprising a plastic seal body 12 and a shackle 14 formed of spring wire. In the illustrated embodiment of the invention the body 12 is provided with a pair of spaced apertures 16 and 18 which extend into the body from the top surface 20 thereof, and a pair of grooves 22, 23, disposed on opposite sides of the body, said grooves being positioned generally medially between the apertures. The shackle 14 is generally Ushaped forming a long leg 24 and a short leg 26, the legs having bights 28 and 30 forming reversely bent end portions 32 and 34, the reversely bent end portions having extreme ends 36 and 38 which are provided with sharpened ends 36 and 38 by being cut at an angle for a purpose to appear hereinafter. The apertures 16 and 18 have a width substantially the same as the diameter of the wire of which the shackle 14 is made, and a length such that when the ends of the shackle legs are pushed into the apertures, the reversely bent end portions 32, 34 are maintained in a flexed condition so that the sharpened ends 36, 38, bear against the inner walls 40 and 42 of apertures 16 and 18 respectively. The seal 10 is normally supplied to the user with the long leg 24 inserted into the aperture 18 and the bight 30 of the shorter leg projecting into the aperture 16, but not so far that the end 38 of the short leg has entered the aperture, (see Figure 1) so that the short leg may be easily removed from the aperture to enable the shackle leg to be passed through a staple 44 or the like of an article to be sealed. Thereafter the bight 30 may be re-inserted into the aperture 16, and both legs pushed into the body so that both reversely bent ends are flexed by engagement with the end walls of the aperture. (See Figure 3). According to a feature of invention the width of the apertures 16, 18, is substantially the same as the diameter of the wire of which the shackle is made and about the same width as that of the strip 46 of material disposed between the grooves 20, 22, to provide a firm support for the pressure of the ends 36, 38, to prevent the pressure of the end of the leg against the plastic from breaking through the aperture wall under conditions of elevated temperature. It has been considered possible that under extremely favorable circumstances that seals of this general type might be defeated by the insertion of a suitable tool, such as a thin piece of steel, into one of the apertures between the leg and the outside wall of the aperture. By manipulation of such a tool, the leg might be forced toward the inner wall, which could tend to flatten the reverse bend portion against said opposite wall. Thereafter, the tool could be removed and the leg could then be drawn out of the aperture without the sharp end of the shackle catching on the inner wall of the aperture, and without leaving evidence of tampering. To eliminate any possibility of defeating such a seal, in the illustrated embodiment of the seal, each leg of the shackle is provided with a laterally inwardly extending U-shaped protrusion 50 formed by a first leg portion 52, a substantially U-shaped bend 54, and a second leg portion 56. In the illustrated embodiment of the invention, the first or upper leg portion 52 of the U-shaped portion is substantially perpendicular to the shackle leg from which it is formed. The second leg portion 54 of the U-shaped lateral protrusion is inclined slightly downwardly, however this leg also could be perpendicular to the shackle leg, if such shape could be provided by the wire bending machinery used to manufacture the shackle. The protrusion has dimensions such that it completely spans the aperture and fits tightly between the sidewalls thereof. With the above described construction, it is substantially impossible to insert a tool of any appreciable thickness into the aperture between the outer wall and the shackle leg, since the U-shaped protrusion prevents any sideways movement of the shackle leg necessary to allow such insertion. Although it might be possible to insert a very thin tool into the aperture, and then attempt to pry the bight against the inner wall of the aperture, the shackle is made of spring wire, and a tool thin enough to enter the aperture would not have enough bending strength to bend the bight to a sharper bend. A lateral extension in the shackle leg is shown in U.S. patent 3,375,033 to Moberg. However the extension shown in Moberg does not completely fill the aperture, and due to the fact that the legs of the lateral extension (not numbered) in Moberg are both inclined at a substantial angle to the side wall of the aperture, it would be possible for a tool to be inserted to first flatten the Moberg protrusion, and then a second thicker tool could be used to force the bight against the inner wall of the aperture to increase the amount bend in said bight for the purpose previously described. It might also be possible to apply sufficient tension to a shackle leg of the seal described herein to cause the U-shaped protrusion to tend to straighten, (See Figure 6) so that is would assume a configuration similar to that of the Moberg protrusion. To render this method of attacking the seal un-productive, the extreme ends of the reversely bent portions are provided with the sharpened ends 36, 38, so that when the tension required to straighten the U-shaped protrusion is applied to a shackle leg, the ends of the legs pierce through the plastic housing and appear in a groove 22 or 24. The ends 36, 38 of the reversely bent ends are preferably beveled at an angle and in a direction such that when tension is applied to the legs, the ends will pierce the walls 40, 42 at the inner ends of the apertures, and the bevel on the ends will tend to force the ends outwardly so that they enter the groove at or about the corner of the aperture against which the sharp edge of the bevel is bearing. The structure of the seal body and shackle, and the above described action by which the shackle end penetrates the seal body is disclosed and claimed in my US utility application Serial 713,320 filed March 18, 1985 and assigned to the same assignee. However, the invention described herein is not limited to use with a seal body having a central groove, since in some cases the shackle may have a configuration such that the sharpened end will pierce some other surface of the body when pulled. Although in the illustrated embodiment of the invention two body apertures and two shackle legs are provided for engagement therein, it will be understood that in some cases one shackle leg may be permanently attached to the body in some other manner, in which case only one aperture and one locking shackle may be provided. Since certain other changes apparent to one skilled in the art may be made in the illustrated embodiment of the invention, it is intended that the description of the illustrated embodiment should be interpreted in an illustrative and not in a limiting sense.

Claims: A seal of the padlock type comprising: a seal body and wire shackle; the seal body having at least one aperture (16, 18) for receiving a leg of the shackle; said leg having a reversely bent end portion (32, 34), said aperture, having a width substantially the same as the diameter of the wire, the wire having a laterally extending portion (52) on the shackle leg, said laterally extending portion being so dimensioned and being so positioned on the shackle leg that when the leg is pushed into said aperture to be in locking engagement with the seal body, said laterally extending portion (52) is within the seal body and completely blocks the cross section of said aperture in the seal body; characterized in that the laterally extending portion (52) has a portion extending substantially perpendicular to the portion of the shackle leg from which it extends. A seal as in Claim 1 in which said laterally extending portion is formed by a generally U-shaped bend (50) in the shackle leg. A seal as in Claim 2 in which the leg (52) of the generally U-shaped bend (50) that is furthest from the reversely bent portion (32, 34) is substantially perpendicular to the shackle leg from which it is formed. A seal as in Claim 1 having a pair of spaced rectangular apertures (16, 18) and wherein said shackle is generally U-shaped forming a pair of legs (24, 26) for entering said apertures (16, 18) each of said legs (24, 26) having a reversely bent end portion (32, 34) which is dimensioned to be flexed toward its associated leg when inserted into a respective aperture, the extreme end of said reversely bent portion being sufficiently sharp to penetrate the material of the seal body into which it is to be assembled and when a substantial pulling force is subsequently applied to an assembled leg, each of said legs (24, 26) having a laterally extending aperture blocking member extending therefrom, said blocking member having a lateral extent (52) which is substantially equal to the corresponding dimension of the aperture into which it is to be inserted and being so positioned on the leg that when the leg is pushed into the seal body to the fully inserted position, the laterally extending blocking member is disposed inside the aperture and extends substantially perpendicular to the portion of the shackle leg from which it extends. A seal as in Claim 4 in which each of said laterally extending aperture blocking members of the shackle is formed by a generally U-shaped bend (50) in its respective leg disposed above said reversely bent portion, said U-shaped bend forming a pair of laterally extending legs at least one (52) of which is substantially perpendicular to the associated leg.

Inventors: SWIFT, ALLAN W.
Applicants: E.J. BROOKS COMPANY
Application year: 1986
Main classification: G09F3
IPC codes: G09F3