GB2312468A - Padlock with sequential counter - Google Patents

Abstract

A padlock or seal comprises a key operable lock 13 and a counter 20 which is indexed on by one digit when the locking mechanism undergoes a change of state from the fully locked position to the open position, but is otherwise prevented from indexing. The seal may have a rigid hasp 2 or flexible hasp (32, Fig 5). The rigid hasp 2 is retained by a key operable bolt 7 whose movement in one direction operates the counter 20, the movement only being possible if the hasp 2 is properly home. The flexible hasp (32) has its nose (34) engaged by a key operable catch (46) whose movement in one direction operates the counter (40). the movement only being possible if the nose (34) is properly entered.

Description

Improvements relatinq to seals This invention relates to seals in the form of locks which not merely secure a door (for example) but which indicate if they have been unlawfully operated or released.

The specification is mostly concerned with padlock type seals but the same principles could be adapted for other kinds of lock. For the present specification, and simplicity of description, reference will just be made to padlocktype seals.

In GB-A-2191534 a padlock was described in which pushing home the hasp into the body of the padlock not only secured the hasp but also incremented a sequential counter.

This registered the number of times the padlock was opened and closed, and it therefore provided a useful security aid.

The authorised user, having noted the number showing when he left the padlock secured, could tell on his return whether someone had managed to undo and then refasten the padlock.

This remains a desirable feature, but in practice at the time it proved difficult to achieve consistent and reliable operation. The engineering within the confines of a padlock body was rather complicated. But more importantly the operation of the counter was not directly and necessarily uniquely controlled by the locking of the device.

It is the aim of this invention to provide an improved version, operating in a somewhat different manner.

According to the present invention there is provided a key operable lock including a counter linked to a lock mechanism to increment by one on a change of state between locked and unlocked, the linkage being such that the counter is inoperable without full and proper closure of the lock mechanism.

The seal may be in padlock form with a body and a rigid hasp. A bolt within the body may co-operate with both legs of the hasp, when pushed in from a released to a sealing position, to retain it fast to the body of the lock, thus forming a closed loop. Preferably, the bolt is divided and is double acting so that the two end portions co-operate with detents in respective legs of the hasp. When unlocked, the bolt releases the hasp and preferably a spring cooperates with one leg of the hasp that is captive to the body to urge the hasp away from the body for the other leg to go clear. The hasp in its free position can then be swivelled about its captive leg.

Preferably, it will be arranged so that when the hasp has been swivelled away from its immediately released position, it will not be possible to push the captive leg back into the body. Nor should it be possible for the bolt to work when the hasp is released, and this may be achieved by the captive leg of the hasp blocking the bolt movement.

If the counter is operated by the movement of the bolt in one direction (preferably the locking direction) it will then be impossible for the counter to be improperly indexed.

As further security, it can be arranged that the key is only insertable and removable when the padlock is closed and locked.

In an alternative arrangement, a seal of padlock form may have a flexible hasp, in which case one end may be permanently anchored to the body while the other end has an element insertable into the body to be retained by a catch, a key actuable member co-operating with the catch to move it between locking and unlocking positions on operation of the key.

Conveniently, the catch is linked to the counter to index the counter when moved in one direction. In the preferred form, a member co-operates with the catch and said element when inserted, the insertion of said element moving said member to a non-interfering position allowing operation of the catch, while absence of said element leaves said member in an interfering position preventing operation of the catch. In the non-interfering position, the member may serve to locate the inserted element in a position for retentive engagement by the catch.

The catch may be rotatable through a limited arc whose ends correspond to the locking and unlocking positions. In that case, the counter can be operated by a rotary spindle in which the catch is mounted.

For a better understanding of the invention, some embodiments will now be described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a cutaway side elevation of a padlock-type seal in the closed or locked condition.

Figure 2 is a similar view of the seal when open, Figure 3 is an underneath plan view of a bolt forming part of the seal; Figure 4 is a perspective view of another padlock-type seal, Figure 5 is an exploded perspective view of components of the seal of Figure 4, with some features omitted, Figure 6 is an end view of part of the locking mechanism of Figure 5, but also showing the features omitted from that figure, and Figure 7 is a cross-section on the line VII - VII of Figure 6, including the body of the seal and omitting the hasp.

The padlock type seal of Figures 1 to 3 is of generally conventional appearance and has a body 1 and a U-shaped hasp 2 with one leg 3 longer than the other leg 4. At symmetrical positions from the crown of the U the legs have notches 5, 6 on the inside forming detents for a bolt 7. The longer leg 3 is captive to the body 1 but is urged outwardly by a spring 8. When the hasp 2 is released, the spring 8 causes the shorter leg 4 to come clear of the body 1, and then the hasp can be swivelled about the leg 3.

The bolt 7 is in two parts 9 and 10 with a sliding overlapping joint. Recesses 11 in the overlapping portions receive fingers 12 at the end of a key operated lock barrel 13 and when the key 14 is turned the fingers twist to cause the parts 9 and 10 to close together (to the unlocked position) and to move apart (to the locking position). In the locking position, the stepped ends of the parts 9 and 10 engage in respective notches 5 and 6 to hold the hasp retracted.

It will be noted that with the hasp free as in Figure 2, the bolt 7 cannot be fully expanded: the end of the part 9 is blocked by the leg 3 beyond the notch 5. Although this portion of the leg 3 does have a flat 15 on the inside allowing a bit of expansion of the bolt 7 this is not enough to operate the counter described below. The flat cooperates with a cross pin 16 which limits the movements of the hasp.

From the locked position of Figure 1 to the immediately freed position of Figure 2, the pin 16 prevents the hasp swivelling by its close proximity to the flat 15. However once the leg 4 is clear, having reached the Figure 2 position, the pin 16 will register with a part circumferential groove 17 near the end of the leg 3 and the hasp can then be rotated about that leg. However, the hasp cannot be pushed back into the body when so swivelled, being prevented by the engagement of the pin 16 in the groove 17: it has to have the leg 4 aligned over the body 1.

The part 9 of the bolt 7 has a lateral notch 18 in which the finger 19 of an incremental counter 20 engages.

The numbers of this counter show through a window 21 in the side of the body 1. The counter is arranged to be operated each time the finger 19 moves to the left as seen in the figures (ie. when the lock is being closed), but not when the finger moves to the right. However, this arrangement could be reversed if desired.

It will be appreciated that every locking (or unlocking) operation increases the counter by one, and that this can only happen when the hasp 2 is properly 'home' and the key 14 is operated.

Referring to the padlock-like seal of Figures 4 to 7, it will be described in terms of being base down on a horizontal surface. It has a body 31 and a flexible wire hasp 32 anchored at one end 33 within the body and terminating in a solid bullet-like nose 34 at the other end. This is generally cylindrical with an annular groove 35 and a rounded end 36, and it can enter the body to engage the locking mechanism via an aperture 37. The seal is released, as described below, by a key 38 inserted horizontally into a barrel lock 39 at a narrow side of the body adjacent the anchored end 33, while the counter 40 displays the current number of operations through a window 41 in one of the larger sides of the body 31. The seal should be uniquely identifiable for recording purposes and will carry a serial number 42 on its side. The seal of Figures 1, 2 and 3 will also be so marked.

Internally, as can be seen in Figure 5, at the end remote from the key entry, the barrel lock 39 co-operates with a rotary plate 43 to turn it about the axis of the lock. A peg 44, offset from that axis, projects in the axially parallel direction from the plate 43 to enter an aperture 45 in a rocker catch 46. This catch is a narrow vertical plate centrally mounted on the spindle 47 of the counter 40, the aperture 45 being at its lower end. Its curved upper end, centred on the spindle 47, is bent over into a generally horizontal flange 48. This flange has a keyhole slot 49 whose longitudinal axis is transverse to the spindle 47. In the unlocked condition, the enlarged circular end or eye 50 of the slot 49 is aligned below the aperture 37. There is a further mechanism associated with the catch 46, not shown in Figure 5 for clarity, which will ensure counting in strict correspondence with proper lock operation. This will be described below with reference to Figures 6 and 7.

To close this seal, the nose 34 is entered through the aperture 37 and into the eye 50. It comes up against a stop (referred to later) with the groove 35 level with the flange 48. The key 38 is then entered, if not already done so, and turned. The plate 43 rotates and the peg 44, by its engagement with the aperture 45, swings the catch 46 on the spindle 47. The flange 48 moves in the opposite direction to the peg 44 to bring the narrow part of the slot 49 below the aperture 37. The edges of this part engage the groove 35 and the nose 34 is trapped. The key 38 can then be removed.

This movement of the catch 46 indexes the counter 40 on by one digit. When the device is unlocked by the reverse procedure, the return movement of the catch 46 cocks the counter for the next operation, and does not alter the number showing.

Referring now to Figures 6 and 7, the rocker catch 46 is shown static, with the nose 34 in its two extreme positions when engaged in the slot 49. The rocker catch 46 has an arcuate slot 51 centred on the spindle 47 a short distance below the flange 48. Its lower edge is smooth, but its upper edge has a step or shoulder 52 making the slot larger at the end adjacent the eye 50. A finger 53 is anchored at 54 to the interior of an end wall of the body 1 to project horizontally through the slot 51 and into an aperture 55 in a plate 56 which provides a bearing for the spindle 46 and thus mounts the rocker catch 46. The finger 53 can flex about anchorage 54 and the aperture 55 allows it limited excursions from its normal relaxed position.

When the seal is open, with the eye 50 below the aperture 37, the finger 53 is in position A, straight and horizontal, and up against the upper edge of the enlarged part of the slot 51.

When the nose 34 is entered, its end 36 pushes the finger 53 down to position B, where it bears on the lower edge of the slot 51, and/or on the bottom edge of the aperture 55. The finger 53 then acts as the stop referred to above to arrest and locate the nose 34 so that the catch 46 can be turned.

The movement of the catch 46 during the locking operation brings the finger 53 to position C, at the smaller end of the slot 51, still on or very adjacent its lower edge, and this occurs before the nose 34 has reached the end of the slot 49. But the finger 53 is flexed sideways by the end of the slot 51 to allow the locking movement to continue, and when that has been completed, the finger 53 is left just clear of the nose 34. It therefore springs up to position D, engaging the upper edge of the slot 51, where it is engageable by the side of the nose 34.

When the seal is unlocked, the catch 46 pivots as described above, the nose 34 keeping the finger 53 flexed to one side as that jumps the shoulder 52. When the nose 34 is aligned with the eye 50, ready to be withdrawn, the finger is at position E, at the larger end of the slot 51, still up against the upper edge.

Following withdrawal of the nose 34, the finger 53 springs back to the starting position A.

It will be seen that this mechanism does not interfere with the ordinary operation of the seal, and that every time the seal is closed, the counter 39 will index on one digit.

However, should there be attempted any operation with the nose 34 not properly entered, the rocker catch 46 will be arrested after only a few degrees of movement by the finger 53 (at position A) engaging the shoulder 52. The finger 53 is of course very limited in its movements by the aperture 55 and cannot be flexed aside to an extent that will allow full movement of the catch 46. Thus the counter 39 can only be indexed when the seal is properly closed, and each indexing requires the seal to be opened and then re-closed.

Claims (16)

1. A key operable seal including a counter linked to a lock mechanism to increment by one on a change of state between locked and unlocked, the linkage being such that the counter is inoperable without full and proper closure of the lock mechanism.

2. A seal as claimed in Claim 1, wherein the seal is in padlock form.

3. A seal as claimed in Claim 2, wherein there is a body and a rigid hasp and a bolt within the body co-operates with both legs of the hasp, when pushed in from a released to a sealing position, to retain it fast to the body of the lock, thereby forming a closed loop.

4. A seal as claimed in Claim 3, wherein a spring cooperates with one leg of the hasp that is captive to the body to urge the hasp away from the body for the other limb to go clear when the bolt releases the hasp.

5. A seal as claimed in Claim 4, wherein there are means preventing the released hasp being pushed back towards the body unless said other limb is aligned with its locking position.

6. As seal as claimed in Claim 3, 4 or 5, wherein there are means preventing the bolt from working when the hasp is released.

7. A seal as claimed in Claim 6, wherein the means preventing the bolt from working is the leg of the hasp which remains captive to the body.

8. A seal as claimed in Claim 6 or 7, wherein the counter is operated by movement of the bolt in one direction.

9. A seal as claimed in Claim 8, wherein said direction is the locking direction.

10. A seal as claimed in Claim 2, wherein there is a body and a flexible hasp one end of which is permanently anchored to the body and the other end of which has an element insertable into the body to be retained by a catch, a key actuable member co-operating with the catch to move it between locking and unlocking positions on operation of the key.

11. As seal as claimed in Claim 10, wherein the catch is linked to the counter to index the counter when moved in one direction.

12. A seal as claimed in Claim 10 or 11, wherein a member co-operates with the catch and said element when inserted, the insertion of said element moving said member to a non-interfering position allowing operation of the catch, while absence of said element leaves said member in an interfering position preventing operation of the catch.

13. A seal as claimed in Claim 12, wherein said member in the non-interfering position locates the inserted element in a position for retentive engagement by the catch.

14. A seal as claimed in any one of Claims 10 to 13, wherein the catch is rotatable through a limited arc whose ends correspond to the locking and unlocking positions.

15. A seal as claimed in Claim 14 as appendant to Claim 11, wherein the counter is operated by a rotary spindle on which the catch is mounted.

16. A key operable seal substantially as hereinbefore described with reference to Figures 1 to 3 or Figures 4 to 7 of the accompanying drawings.