Door locking mechanisms for security enclosures

Abstract

 The door of a safe or the like has a locking mechanism comprising one or more locks 8,9 in a module installed separately from the boltwork which are effective to operate pivotally-borne blocking members 16-19 to block forced retraction of the boltwork.

Description

[0001] The present invention relates to safes, vaults, strongrooms and the like security enclosures, and more particularly to locking mechanisms for the doors of such enclosures.

[0002] It is customary for the door of a safe or the like to be locked by means of bolts thrown from one or more edges of the door into engagement with the surrounding frame, for which purpose there is provided an externally-accessible handle, wheel or the like operating member which drives the boltwork through a mechanical transmission mounted within the door, the same mechanism, of course, being used to withdraw the bolts when the door is to be opened. This boltwork is in turn locked in its thrown condition by the operation of one or more locks which throw their own bolts or other abutments into blocking positions in relation to the main boltwork or its transmission to resist subsequent retraction of the main bolts under forcing loads. The present invention relates to various aspects of a mechanism of this kind which are particularly exemplified below. One such aspect is the provision of one or more pivotal blocking member(s) which are turned to position(s) in which they block forced retraction of the main bolt(s) thrown from a respective edge of the door, by means of a pin-and-slot (or equivalent) coupling with a reciprocable operating member driven by operation of a said lock.

[0003] The invention will therefore be more particularly described, by way of example only, with reference to the accompanying drawings, in which:-

Figure 1 is a rear elevation of a preferred embodiment of a mechanism according to the invention, shown in its locking condition;

Figures 2 and 3 are views of the mechanism of Figure 1 respectively from the leading side edge and hinge side edge of the door;

Figure 4 shows the two locks of Figure 1 to an enlarged scale; and

Figure 5 is a section through a relocker provided in the mechanism.

[0004] Throughout the description, all indications of relative direction or movement, such as "upwards", "downwards", "left", "right", "clockwise" and "anticlockwise" apply to the mechanism in the sense in which it is viewed in Figure 1.

[0005] Referring to Figures 1-3, there are shown the principal components of the door locking mechanism for a safe, which are assumed to be mounted in the door behind a layer of security barrier material formulated to resist breaching of the door while it remains closed and locked. The illustrated assembly can in particular be produced as a module for installation in an existing or separately-manufactured safe door equipped with its own main bolts. In the illustrated embodiment the mechanism will include sets of main bolts (not shown) which can be thrown into detentions in the associated door frame through all four edges of the door, each such set being carried by a respective bolt strap attached to a respective drive bar 1,2,3 or 4. The bar 1 transmits movement to bolts at the upper edge of the door, bar 2 to bolts at the leading side edge of the door, bar 3 to bolts at the lower edge of the door and bar 4 to bolts at the hinge side edge of the door. All of these bars can be extended and retracted in unison by a central thrower which comprises a slotted disc 5 engaging a respective drive pin 6 on each bar. The disc 5 is connected to a spindle 7 which passes through the thickness of the door to an external handle or wheel by which it can be turned to throw out or withdraw the main bolts in accordance with its sense of rotation.

[0006] The above-described boltwork can be locked when thrown by a pair of locks which in the illustrated embodiment comprise a keylock 8 and a separate keyless combination lock 9. The latter is of the offset type in which the shaft 10 from the external dial is coupled to the driver through a gear train 11. The bolt 12 of the keylock 8 is connected to a bar 13 which carries an abutment 14 which engages in a peripheral notch 15 in the thrower disc 5 when the boltwork is thrown and the keylock 8 is operated to extend its own bolt (i.e. downwards). By this means the disc 5 is blocked from withdrawing the main bolts if force is applied to the external handle or wheel and if end pressure is applied to any of the main bolts themselves in an attempt to drive them in it will be resisted through the connection of the respective drive bar 1-4 to the blocked disc 5. It is recognised, however, that some additional means is desirable for resisting forced retraction of the main bolts during an attack upon the safe, independently of the abutment 14, at least for those bolts which are thrown through the top, leading side edge and bottom of the door, and for this purpose three additional blocking members 16,17 and 18 are provided, for cooperation with respective bars 19,20 and 21 which are rigidly attached to the respective bolt straps at those three edges so as to move in unison with the respective main bolts.

[0007] More particularly, the blocking member 16 is mounted on a fixed pivot 22 and is turned anticlockwise to place an abutment face 23 behind the bar 19 when the main bolts are thrown, by operation of the combination lock 9. That is to say the bolt 24 of the lock 9 carries a bar 25 which is connected by a pin and slot 26 to a crank 27 on a fixed pivot 28. The latter is connected by a pin and slot 29 to a bar 30 which is borne to reciprocate horizontally and is in turn connected by a pin and slot 31 to the blocking member 16. Accordingly, when the lock bolt 24 is extended (i.e. moved downwards) the bar 30 is shifted to the right to pivot the member 16 to its illustrated blocking position. On the other hand, when the correct combination is set in the lock 9 and its dial is turned to retract the bolt 24 the bar 30 is shifted to the left to pivot the member 16 clockwise to a position in which a central slot 32 in that member is aligned with the bar 19 and accordingly permits withdrawal of the bolt strap by which that bar is carried.

[0008] The blocking members 17 and 18 are mounted on fixed pivots 33 and 34 and are turned respectively anticlockwise and clockwise to place abutment faces 35 and 36 behind the bars 20 and 21 when the main bolts are thrown, by operation of the key lock 8. That is to say the bar 13 carried by the key lock bolt 12 is connected by a respective pin and slot 37,38 to the two blocking members 17 and 18 to pivot them to their illustrated blocking positions when the bolt 12 is extended. On the other hand, when the lock bolt is retracted to raise the bar 13, the members 17 and 18 are pivoted in the opposite respective senses to positions in which their central slots 39 and 40 are aligned with the bars 20 and 21 and accordingly permit withdrawal of the respective bolt straps by which those bars are carried.

[0009] It will be observed that the three blocking members 16, 17 and 18 are in fact of identical form, with member 18 being mounted in a reverse disposition to members 16 and 17. They each have an additional abutment face 23A, 35A and 36A respectively which is not employed in the illustrated embodiment but by which the same components may be used in a similar mechanism for a door of opposite hand to that illustrated.

[0010] As more clearly seen in Figure 4, associated with the key lock 8 is a reciprocable shutter plate 41 having a contoured aperture 42. When this plate is shifted to the right from the illustrated position the larger, vertical limb of the aperture 42 aligns with the key entrance to the lock 8 but when it is in the illustrated lefthand position only part of the smaller, horizontal limb of the aperture 42 aligns with the key entrance. This plate is linked to the combination lock 9 so that when the latter is unlocked the plate 41 is shifted to the right and the key for the lock 8 can be inserted and withdrawn, but when the combination lock is locked the plate 41 is shifted to the left and can trap within the key lock an inserted bitted filler piece, or blank key, and therefore blocks access through the key entrance to any picking tool. In this respect the bolt 24 of the combination lock carries a plate 43 which is connected by a pin and slot 44 to a lever 45 on a fixed pivot 46. The lever 45 carries a pin 47 which works in a slot 48 in the plate 41 to shift the latter in accordance with the sense in which the lever is pivoted by the plate 43. In the illustrated locking position the pin 47 lies in an overcentre position relative to pivot 46 in the sense of any external load applied to the plate 41 in the rightwards direction. Thus if any attempt is made to force the plate 41 to the right during an attack upon the safe in order to unblock the entrance to lock 8, the load transmitted from that plate to the pin 47 will tend to force that pin and the lever 45 in the anticlockwise sense, hard against the plate 43 and the extended combination lock bolt 24. Thus will not only the load upon the plate 41 be securely resisted, it will also be transmitted to the bolt 24 in the sense of extension of the latter and thus resist manipulation of the combination lock.

[0011] An additional feature of the illustrated mechanism to thwart forcible attack upon the safe is a glass-triggered relocker. This comprises a sheet 49 of glass or similar frangible material (Figs 1, 2 and 4) extending behind the security barrier layer so as to be located between the front face of the door and all of the vital locking and blocking components of the mechanism. The sheet 49 is connected by a cord 50 to a bolt 51 (see also Figure 5) biased by a spring 52 to extend from a housing 53. The bolt 51 is normally held against the action of the spring 52 by the cord 50 in its unblocking position of Figure 5. If, however, the sheet 49 should be shattered by gross force applied to the safe or by any tool penetrating through the door to the area covered by the sheet, the tension in the cord 50 will be relieved and the bolt 51 allowed to extend from the housing 53 under the action of the spring 52, to the extent permitted by a stop pin 54 running in a slot 55 in the housing. When triggered in this way the bolt 51 is held in its extended position by a spring-loaded plunger 56 seen in Figures 1 and 4. In this condition the bolt 51 will act as a further blocking member resisting the forced retraction of the leading edge bolt strap through a bar 20A carried by that strap in parallel with the bar 20.

[0012] A second relocker is shown in Figures 1 and 4 for applying a further blocking action upon the horizontal bar 30 (and hence the blocking member 16 and combination lock bolt 24 linked to it) in the event that the cover plate 57 of the mechanism should become dislodged during an attack upon the safe. This comprises another spring-loaded bolt 58 in a housing 59 which is normally held in its unblocking position by a boss 60 (Fig 3) on the cover plate 57. Should the latter be dislodged, however, the bolt 58 will be freed to move through the housing 59 to the extent permitted by a stop pin 61 and thus block retraction of a pin 62 carried by the bar 30. A spring-loaded plunger is shown at 63 for holding the bolt 58 in its extended position when triggered in this way. While the bolt 58 remains in its unblocking position, however, normal retraction of the pin 62 and bar 30 under the control of the combination lock 9 is permitted by the reception of the pin 62 in a bore 64 in the side of the bolt. The reception of the pin 62 in the bolt 58 also provides a means for preventing release of the latter when the cover plate 57 is removed by authorised personnel e.g. for servicing of the lock mechanism, since in those conditions the lock bolt 24 and bar 30 will have previously been retracted by authorised operation of the lock 9.

Claims

1. A locking mechanism for the door of a security enclosure, comprising: boltwork; a mechanical transmission (1-7) for throwing and withdrawing the boltwork in response to corresponding operation of an externally-accessible operating member; and at least one lock (8,9) for selectively locking the boltwork in its thrown condition; characterised by at least one pivotally-borne blocking member (16-18) which is turned, by operation of a said lock (8,9) to its locking condition, to a position in which it is adapted to block forced retraction of at least part of the boltwork.

2. A mechanism according to claim 1 wherein said boltwork comprises main bolts adapted to be thrown from a plurality of edges of the door and comprising a plurality of said blocking members (16-18) each adapted to serve as an abutment behind the bolts thrown from a respective said edge.

3. A mechanism according to claim 1 or claim 2 wherein operation of a said lock (8,9) to its locking condition is effective to shift a linearly-movable member (13,30) to which a said blocking member (16-18) is linked so as to be turned thereby.

4. A mechanism according to claim 3 wherein said blocking member (16-18) is linked to said linearly-movable member (13,30) through a pin and slot (31,37,38).

5. A mechanism according to any preceding claim comprising first (8) and second (9) locks, the first lock (8) being a key lock and the second lock (9) being effective to at least partially restrict access to the key entrance of the first lock (8) when the second lock (9) is in its locking condition.

6. A mechanism according to claim 5 wherein the second lock (9) has a bolt (24) linked through a pivotal member (45) to a shutter member (41) for restricting access as aforesaid, the pivotal member (45) being in an overcentre condition with respect to said bolt (24) when the second lock (9) is in its locking condition whereby force applied to the shutter member (41) in the sense to derestrict access to the key entrance of the first lock (8) is transmitted to said bolt (24) in the sense to extend the same.

7. A mechanism according to claim 5 or claim 6 wherein the second lock (9) is a keyless combination lock.

8. A mechanism according to any preceding claim wherein said transmission includes a rotary thrower (5), turning of which by said operating member is converted to linear movement of one or more drive bars (1-4) connected to main bolts adapted to be thrown from a respective edge of the door, and operation of a said lock (8) to its locking condition is effective to move an abutment (14) into engagement with said thorwer (5) thereby to lock the boltwork.

9. A mechanism according to any preceding clim having a cover plate (57) to overlie at least said lock(s) (8,9) and blocking member(s) (16-18), said cover plate (57) being linked to a secondary locking member (58) which is operative to block forced retraction of the boltwork if the cover plate (57) is dislodged.

10. A mechanism according to claim 9 wherein retraction of the boltwork with said lock(s) (8,9) unlocked is effective to prevent operation of said secondary locking member (58).

11. A door of a security enclosure provided with a locking mechanism according to any preceding claim, wherein at least said lock(s) (8,9) and blocking member(s) (16-18) are comprised in a module which is installed in the door separately from the installation of the boltwork.

Drawing