AU665303B2

AU665303B2 - Pick resistant lock

Info

Publication number: AU665303B2
Application number: AU59211/94A
Authority: AU
Inventors: Brian Francis Preddey
Original assignee: Australian Lock Co Pty Ltd
Current assignee: Australian Lock Co Pty Ltd
Priority date: 1993-03-31
Filing date: 1994-03-30
Publication date: 1995-12-21
Anticipated expiration: 2014-03-30
Also published as: AU5921194A

Description

!J W'I 1 4 1UIUII 21VUDI Rogulation 3.2(2)

AUSTRALIA

Patents Act 1990 3 0 3

ORIGINAL

COMPLETE SPECIFICATION STANDARD PATENT ~~44f4 C C gd C t C C ~444 r t C CC t t C C C CCC C Application Number: Lodged: *C44 CC 4 CI CC C I C .44.

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Invention Title: PICK RESISTANT LOCK The following statement is a full dezcription of this invention, including the best method of performing it known to us PICK RESISTANT LOCK Technical Field The present invention relates to locks of the type employing biased pins, and lock bars.

Background Art Most locks may be thought of as mechanically coded devices.

The code is provided by lock pins which prevent release of the lock when they are incorrectly aligned. When a key is inserted into a lock, the pins are aligned according to the profile of the key. When this ~i 0 profile aligns the pins correctly the lock can be released.

ij :~>:Figure 1 illustrates such an arrangement. Lock cylinder 3 is operatively received inside body 13, and lock bars 6 prevent relative rotation. When the correct key 4 is inserted into the cylinder, pins form a particular arrangement, such that holes 8 in the pins 5 are S 1 5 aligned horizontally.

t d When the holes are correctly vertically positioned, and aligned, the projections 9 on side bars 6 are received within holes 8, i~i~ the side bars 6 can move inward, and the lock is released.

To circumvent the need to try all possible coding arrangements, a person trying to penetrate the security arrangement of a particular lock will use a lock picking tool. This tool is inserted I into the lock and the user manipulates each pin until the hole 8 in the pin 5 is detected as engaging the projection 9 on the sido bars 6. In this way the code of the lock may bo broken.

Such a lock as shown in fig 1 is relatively difficult for a would-be thief to pick. However, it is an object of the present invention to increase the difficulty with which such a lock may be picked.

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4 444f t 4 Summary of Invention According to one aspect the present invention provides an improvement in a lock of the type including a plurality of lock pins, and one or more side bars wherein each side bar has a plurality of projections which are received by recesses in the lock pins upon the action of an appropriate key which operates to align the recesses in the pins with the projections on the one or more side bars so that said side bars can be displaced to effect release of the lock, the improvement wherein at least one of said lock pins includes a first recess of the correct depth to release said side bar, and one or more additional recesses each having a different depth to said first recess, said first and additional recesses presenting substantially similar openings so that they receive the projections in a similar manner.

According to another aspect the present invention provides an improvement in a lock cylinder of the type which is adapted to be received by a lock body and which includes a plurality of lock pins, and one or more side bars wherein each side bar has a plurality of projections which are received by recesses in said lock pins upon the action of an appropriate key which operates to align the recesses in the pins with the projections on the one or more side bars so that said side bars can be displaced to effect release of the lock, the improvement wherein at least one of said lock pins includes a first recess of the correct depth to release said side bar, and one or more additional recesses each having a different depth to said first recess, said first and additional recesses presenting substantially similar openings so that they receive the projections in a similar manner.

3 According to another aspect the present invention provides a lock pin which is adapted for use in a lock of the type which includes a plurality of lock pins, and one or more side bars wherein each side bar has a plurality of projections which are received recesses in said lock pins upon the action of an appropriate key which operates to align the recesses in the pins with the projections on the one or more side bars so that said side bars can be displaced to effect release of the lock, the improvement wherein at least one of said lock pins includes a first recess of the correct depth to release said side bar, and one or more additional recesses each having a different depth to said first recess, said first and 9 additional recesses presenting substantially similar openings so that they receive the projections in a similar manner.

.It is preferred that the improvement include additional recesses that are of sufficient depth to engage the projections Swithout releasing the side bar.

It is preferred that the additional recesses of the improvement are of the same depth on each lock pin.

4 It is preferred that all the additional recesses of the improvement be of the same depth.

It is preferred that the addi..Dnai recesses of the improvement extend to a depth of less than half way through the one or more lock pins.

By utilising a tool which can manipulate each pin individually the power of say, an 8 pin lock with four hole positions on each pin, to present 84 4096 different pin combinations, is circumvented and the lock pick need only consider 32 different pin positions.

4 An advantage of one preferred embodiment of the present invention is that it over comes the ability of the tool to consider the pins independently. If all four hole positions on the pins are occupied by either an operative hole or an additional hole and the lock pick is unable to detect the difference, then considering each pin individually will be of no assistance as the lock pick will not know which hole position on the pin is correct. Accordingly the lock pick will have to consider all 4096 combinations rather than just 32.

Brief Description of Drawings 10 One illustrative embodiment of the present inve;ition will now be described with reference to the accompanying drawings, in which: Figure 1 illustrates a known lock; Figures 2A to 2D illustrate plan views of lock pins including additional holes; Figure 3 illustrates various positions for holes and additional holes in a pin; and Figures 4A and 4B are sectional views along lines A to A and t B to B respectively, showing additional and full depth holes in the pins.

Detailed description of the preferred embodiment The present invention seeks to make it more difficult to feel whether a pin being illicitly manipulated has been pushed into the correct position for the side bar to align and release the lock.

The person manipulating the pins will feel the pin aligning with both the additional holes 12 and the operative hole 8. This substantially increases the difficulty with which a lock may be picked.

p4 i P Figures 2A to 2D show lock pins 5 with operative holes 8 (open circles) in four different positions. On each of the different pins there is located two additional holes 12 which are of the same diameter as the operative hole. Being of the same diameter means that engagement of the projections on the side bar with the additional hole will essentially feel the same as for .ngagement of the projection with the operative holes.

It will be appreciated that the number of additional holes, and their positions, may be varied according to the application. The 10 range of possible holes in the pin can be seen from Figure 3 where .off i4et five possible hole positions are marked on the pin. It can be seen that some of these hole positions overlap, making it possible, for the particular geometry shown to only have three holes in any one pin.

i Figure 4A shows an operative hole, and 4B a additional hole, both in section. It will be appreciated that the side bar projections t¢ cannot locate far enough into the pin for the side bar to release on I r the additional holes. However the side bar projections are received t far enough into the pin that the engagement between the projection and the hole would feel to a lock pick similar to engagement of the projection with the orerative hole.

Variations within the scope of the invention include varying the thickness of the projections or using projections which are square or oval in shape or of some other shape. It may also be desirable to utilise additional holes of different depth rather than employing additional holes of uniform depth, as this may further hinder the senses of the lock pick should they be able to perceive the difference between an additional hole and an operative hole.

Other variations and additions are possible within the spirit 6 and scope of the disclosure, as will be apparent to those skilled in the art.

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Claims

1. In a lock of the type including a plurality of lock pins, and one or more side bars wherein each side bar has a plurality of projections which are received by recesses in the lock pins upon the action of an appropriate key which operates to align the recesses in the pins with the projections on the one or more side bars so that said side bars can be displaced to effect release of the lock, the improvement wherein at least one of said lock pins includes a first recess of the correct depth to release said side bar, and one or more additional recesses each having a different depth to said first recess, said first and additional recesses presenting substantially similar openings so that they receive the projec'ons in a similar manner, and said additional recesses being of sufficient depth to engage the projections without releasing the side bar.

2. The improvement according to claim 1, wherein each of said additional recesses are of the same depth on each lock pin.

3. The improvement of any preceding claim wherein said additional recesses are of the same depth.

4. The improvement according to any preceding claim wherein the additional recesses extend to a depth of less than half way through the one or more lock pins.

I; 8 In a lock cylinder of the type which is adapted to be received by a lock body and which includes a plurality of lock pins, and one or more side bars wherein each side bar has a piurality of projections which are received by recesses in said lock pins upon the action of an appropriate key which operates to align the recesses in the pins with the projections on the one or more side bars so that said side bars can be displaced to effect release ot the lock, the improvement wherein at least one of said lock pins includes a first recess of the correct depth to release said side bar, and one or more additional recesses each having a different depth to said first recess, said first and additional recesses presenting substantially similar openings so that they receive the projections in a similar manner, and recesses being of sufficient depth to engage the projections without releasing the side bar.

6. The improvement according to claim 5, wherein each of said additional recesses are of the same depth on each lock pin.

7. The improvement according to claim 5 or claim 6 wherein said additional recesses are of the same depth.

8. The improvement according to any one of claims 5 through 7 wherein the additional recesses extend to a depth of less than half way through the one or more lock pins. 1-4 9

9. A lock pin which is adapted for use in a lock of the type which includes a plurality of lock pins, and one or more side bars wherein each side bar has a plurality of projections which are received recesses in said lock pins upon the action of an appropriate key which operates to align the recesses in the pins with the projections on the one or more side bars so that said side bars can be displaced to effect release of the lock, the improvement wherein at least one of said lock pins includes a first recess of the correct depth to release said side bar, and one or more additional recesses each having a different depth to said first recess, said first and additional recesses presenting substantially similar openings so that they receive the projections in a similar manner, and said additional recesses are of sufficient depth to engage the projections without releasing the side bar.

The improvement according to claim 9, wherein each of said additional recesses are of the same depth on each lock pin.

11. The improvement according to claim 9 or claim 10 wherein said additional recesses are of the same depth.

12. The improvement according to any one of claims 9 through 14, wherein the additional recesses extend to a depth of less than half way through the lock pin. SDated this 6th day of October, 1995. AUSTRALIAN LOCK COMPANY PTY. LTD. WATERMARK PATENT TRADEMARK ATTORNEYS FLOOR 4, AMORY GARDENS, I( 2 CAVILL AVENUE, AS; IFIELD, NSW 2131. PNF:GL DOC24 AU000348.WPC •U ku l~v~r 0 pr ABSTRACT In lock arrangements the same as or similar to pin tumbler locks it is desirable to increase their resistance to being picked. To achieve this the present invention provides additional holes on the pins which receive the projections from the locks side bars. By creating the additional holes with openings similar to the operational holes, it is difficult for the lock pick to tell the difference between the operational hole and these additional holes. This increases the difficulty with which a lock pick can break the code of the lock. i C 1 1 I t