US2842950A - Tamperproof locking lever equipped padlocks - Google Patents

Description

July 15, 1958 H. E. soREF ETAL 2,842,950

TAMPERPROOF LOCKING LEVER EQUIPPED PADLOCKS Filed Aug. 15, 1956 WH/ i if@ 2,542,950 Patented July l5, 1958 TAMPERPRGF LOCKING LEVER EQUIPPED PADLCKS Harry E. Soref, Milwaukee, and Daniel J. Foote, Wauwatosa, Wis., assignors to Master Lock Company, Mib waukee, Wis., a corporation of Wisconsin Application August 15, 1956, Serial No. 604,122

1 Claim.. (Cl. 70--3fi) This invention relates to improvements in tamperproof locking lever equipped padlocks, and more particularly to a locking lever equipped padlock wherein the locking lever is formed so as to render ineffectual the operative insertion of shims or the like around a leg of the padlock shackle with the intent of thereby engaging andrunauthorizedly manipulating the locking lever of the padlock.

ln the manufacture of padlocks of the pin tumbler, disc tumbler, lever and Wafer types, whether the padlock bodies or cases be of solid stock, die cast or laminated, it is the practice to provide one or more locking levers within the padlock body, which levers, whether they be of straight bar formation, L-shaped, round bolt, or any type having one end thereof cut at an angle, and Whether they be spring urged, cam driven, or manually operated, are adapted and intended to enter shouldered recesses in the legs of the padlock shackles to hold the shackles in their inner retracted positions when the padlocks are closed and locked. Regardless of the specific shape of the lock- *ing levers, each one generally has an end adapted to rectilinearly and evenly iit into the cut or shouldered recess in a shackle leg, and the locking lever may be slightly wider than the width of the shackle so as to permit full and adequate engagement with the shackle whereby the lockmg lever will securely hold the shackle in its inner retracted or locked position, preventing the shackleV from being forced outwardly under pressure or tension.

Padlocks of the type under consideration also have their body portions provided with a'pair of spaced longitudinally Vextended openings of uniform size and shape in order to receive both the extended leg and the short leg or toe of the padlock shackle. lt is the practice to form said shackle openings of uniform diameter and of slightly greater diameter than that of the shackle legs for smooth and easy longitudinal movement of the shackle as the padlock'is opened and closed, and to furthermore facilitate shackle alignment and to compensate for slight variations in the size and shape of the shackle legs. The locking lever of a padlock (sometimes known as the bolt) is one of the important internal operating elements of the pad lock and all action of mechanism within the padlock is intended to accomplish the release of the locking lever so as to permit the shackle to` be moved outwardly with the short leg or toe free of the padlock body whereby the padlock is opened. The release of the shackle may belaccomplished by a manual operation of a key inserted into the padlock body which operates certain internal mechanism to cause movement of the lever, or by some imparted movement .which retracts the locking lever under spring action or tension. e

`The locking lever lin a padlock of the type described must project somewhat into a shackle opening to anf extent to cause an endportion of the locking lever to enter and engage the recessed and shouldered portion of the shackle leg. Consequently, if the last-mentioned projection portion of the locking lever can -be unauthorizedly forced back or retracted while the 'padlock is closed and locked, then the effect of the engagement between the shackle and locking lever is nulliiied and the padlock can be unauthorizedly opened. Due to the fact that the shackle-receiving openings in a padlock body or case are of slightly greater diameter than that of the legs of the padlock shackle and the fact that the holes, due to wear and tear and use may enlarge somewhat, burglars, thieves and tamperers have developed the art of surreptitiously opening such padlocks by the use of thin metal tools, bits or picks, hereinafter designated as shims, which are inserted into a portion of a shackle opening of the padlock body about a shackle leg and by force and pressure are manually moved arcuately in either direction to contact and retract the locking lever or bolt (whether or not is is under spring tension), thereby producing an unauthorized release and opening of the padlock without the owners knowledge and consent and without the use of a key or a dialing operation (in respect to combination or keyless padlocks).

With the foregoing in mind it is, therefore, a primary object of the present invention to provide in a padlock a specially constructed tamperproof locking lever having its shackle leg engaging end properly positioned corner cuts or recesses which are effective to receive edge portions of a thin metal shim or the like inserted within a shackle hole and which prevent the manipulated shim from contacting the locking lever at such points where pressure applied thereagainst would unauthorizedly retract the locking lever and thus release the shackle.

In padlocksof the type under consideration the shackle legs are intended to have slight lateral play or movement within the body openings therefor, and this is true of that portion of the short leg or toe of the shackle which is recessed and shouldered for releasably receiving the locking lever or bolt of the padlock. ln the present invention the locking lever is formed with cuts or recesses in the corner portions of its shackle-engaging end which still leave sufficient stock for proper engagement within the shouldered recess in the shackle leg, but the elimination of sto-ck from the corner portions of the end of the locking lever which would normally extend laterally of the sides of the shackle eliminates stock which could be effectively engaged and forced back by the movement of a shim inserted in the opening around the shackle leg.

A further object of the invention is to provide in a padlock of the character described, a locking lever or bolt having its shackle-engaging end suitably recessed in a manner to receive within a recess a portion of a shim positioned in the padlock body case around the shackle in a manner to prevent the shim from operatively engaging the locking lever in a manner whereby it could be retracted or forced back free of engagement with its shackle leg.

A further object of the invention is to provide in a padlock a tamperproof locking lever having end recesses or cuts which do notinterfere with the normal movement and operation of the padlock shackle and which will not be affected by wear and frequent operation of the padlock, but. which will prevent unauthorized opening of the padlock by a retraction of the locking lever through a tamperers insertion of a shim or the like around the padlock shackle.

` A further object of the invention is to provide in a padlock of the character described a novel form of locking -lever or the like which prevents unauthorized operation is eifective in use, which increases the utility, performance and safety of the padlock, and which is well adapted for the purposes described.

In the accompanying drawings, in which the same reference characters indicate the same parts in all of the views:

Fig. l is a vertical sectional view through a solid body -padlock provided with the improved tamperproof locking lever;

Fig. 2 is a horizontal sectional view taken along the line 2-2 of Fig. 1;

Fig. 3 is Ia sectional view taken along the line 3 3 of of tamperproof locking lever;

Fig 7 is a side view thereof; and

Fig. S is a fragmentary vertical sectional view through -the shackle-equipped end of a padlock wherein the body is of laminated construction, the padlock body being equipped with the improved tamperproof locking lever.

Although the invention is not to be restricted thereto,

for purposes of illustration, in the principal form of the invention, the padlock body or case is of solid construction and is provided internally with partitions and walls to define cavities for certainv of the lock mechanism. Housed within cavities within the case 10 area spring urged locking lever or bolt 11 and a key-operated cylinder 12 housing pins and having a mutilated inner end portion 12 which is adapted to engage and reciprocate the locking lever 11 under the action of a proper key inserted into the cylinder 12. While the padlock illustrated in Fig. l is of the pin type it could, Within the scope of the present invention, be of the disc tumbler, lever and wafer types. Also, While a solid padlock body or case 10 is illustrated in Figs. l, 2, and 3, the case could be of laminated construction as indicated at 10 in the modification shown in Fig. 8.

' Regardless of the form the padlock case takes, it is provided with a pair of spaced-apart longitudinally extended shackle leg receiving openings 13 and 14 which open through the top or outer end of the padlock casing and which longitudinally movably receive, respectively, the long leg 15 and the short leg or -toe 16 of the padlock shackle 17. The short leg or toe 16 of the padlock shackle at its inner end is provided with a shouldered notch 18 which is engaged by the projected end portion of the locking lever or bolt 11 for shackle locking purposes.

ln the manufacture of a padlock body or case the shackle-receiving openings 13 and 14 are of uniform size and shape and are of slightly greater diameter than that of the shackle legs for smooth and easy longitudinal movement or the shackle as the padlock is opened and clos-ed, and to facilitate shackle alignment and compensate for slight variations due to wear. Consequently there is slight clearance between the shackle leg openings 13 and 14 and the shackle legs 15 and 16, which clearance additionally permits free operation of the shackle, should foreign matter or dirt enter the shackle openings.

The necessity for slight clearance as between the walls of the shackle holes and the inserted legs of the shackle has invited burglars, thieves and tamperers to develop the art of surreptitiously opening such padlocks by the use of thin metal tools, bits or picks, designated as shims, which are inserted into a portion of the shackle opening about a shackle leg and which by force and pressure arc manually moved arcuately in either direction to contact and rearwardly retract the locking lever or bolt from the shackle toe, thereby producing an unauthorized opening of the padlock without the owners knowledge and consent and without the use of a key or dialing operd ation (should the lock be a combination or keyless padlock).

To guard against this unauthorized tampering practice the present invention provides a special form of locking lever 11 shown in detail in Figs. 4 and 5 and in relation to the shackle toe and other structure in Figs. 1, 2 and 3. It is desirable that the locking lever be slightly wider than the width of the shackle toe so as to permit full and adequate engagement with the shackle in order that the locking lever will securely hold the shackle in its inner retracted or locked position and prevent the shackle from being forced outwardly under pressure or tension. In the principal form of the invention L-shaped cuts or recesses 19 are formed in the laterally projecting corners of the engaging end of the locking lever to define therebetween a tongue. As will appear from the drawing, ample stock nevertheless remains between the cut-away portions 19 for proper engagement within the shouldered recess in the shackle leg 16, but the elimination of stock from the corner portions of the engaging end of the locking lever 11 which would normally extend laterally of the sides of the shackle leg removes stock which could be effectively engaged and forced back by the movement of a shim inserted into the opening around the shackle leg. The last-mentioned condition is shown in Fig. 3, wherein a thin metal shim 20 has been inserted into the shackle leg opening 14 about a portion of the shackle toe 16 and the shim has been turned arcuately in a manner which would normally contact and activate and unauthorizedly retract the locking lever 11. However, the end of the shim 20 as at (A) enters the locking leg recess 19 and is thereby prevented from contacting with force such portion of the locking lever 11 which would permit the shim to move the locking lever rearwardly in a rectilinear path to disengage it from the shackle toe. The locking lever recess 19 in which the end of a shim 20 moves prevents movement of the shim in a full circular course so as to slide between the engaging end of the locking lever and the shackle leg. Also the diversion of the end portion of the shim into a corner recess 19 may cause the shim to break if pressure is applied thereagainst and create a jamming action, or the end of the shim may curl somewhat within the corner recess 19. By blocking circular movement of the shim relative to the locking lever any attempted operation of the shim for the purpose of unauthorizedly opening the lock is rendered ineffectual and the shim, if torn or distorted, may become jammed and be difficult to remove.

In Figs. 6 and 7 a slightly modified form of tamperproof locking lever 11 is illustrated wherein, in lieu of full L-shaped corner notches in the engaging end of the locking lever, narrower recesses or slots 21 are provided which define a tongue therebetween which would receive the end of an inserted shim 20 as in Fig. 3 and render its movement within the shackle opening ineffectual for lock opening purposes.

From the foregoing description it will be apparent that the improved tamperproof locking lever-equipped padlock is such that the engaging end of the locking lever with L-shaped corner recesses or slots eifectively prevents the operation of a locking lever releasing shim, without complicating the manufacture and operation of the padlock. The padlock with the tamperproof locking lever is of simple and novel construction and is well adapted for the purposes described.

What is claimed as the invention is:

In a tamperproof padlock having a body with a circular opening extending inwardly from one end, a shackle having a recessed leg of circular cross-section movably received by said body opening, and a locking lever longitudinally reciprocatably mounted within the body at right angles to the axis of said shackle leg, each corner of the outer end of said locking lever being formed with a right angular shoulder to provide therebetween a reduced tongue of a width less than the width of the recess in said circular cross-section leg to releasably extend within said circular body opening, but the tongue being of less length than the depth of the shackle leg recess, each locking lever shoulder having a longitudinal leg parallel to the axis of the locking lever and a leg transverse to the axis of the locking lever, with the transverse legs being intersected by the periphery of the body opening closely adjacent the apexes of the locking lever shoulders, the latter being slightly outwardly of the periphery of the body opening whereby circular movement of a shim inserted into the body opening around the shackle is restrained by contact with the longitudinal leg of a shoulder 6 of the locking lever and is deected into the shoulder apex to prevent such application of force to the locking lever longitudinally of its axis as will cause a longitudinal reciprocation of the locking lever to release it from the shackle.

References Cited in the le of this patent UNITED STATES PATENTS 1,261,423 Miller Apr. 2, 1918 1,622,999 Frith Mar. 29, 1927 2,557,028 Deutsch June l2, 1951

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