GB2076459A

GB2076459A - Safe door lock

Info

Publication number: GB2076459A
Application number: GB8113790A
Authority: GB
Original assignee: THORNE TREVOR ALBERT
Current assignee: THORNE TREVOR ALBERT
Priority date: 1980-05-06
Filing date: 1981-05-06
Publication date: 1981-12-02

Abstract

A door suitable for a floor safe has bolts (62, 64) having rack surfaces (32) engaged by one or more pinion wheels 60. A lock (16) acts via the racks and pinions to displace the bolts to project from or retract within the door. Spring(s) (72) urge the bolts to project. If a burglar damages the racks and pinions, this leaves at least one bolt projecting with no means for retracting it. Removal of the lock (16) may cause an element (74) to move to lock the or each bolt against retraction and/or cause a dead lock bolt (46) to project. <IMAGE>

Description

SPECIFICATION Safe door lock The invention relates to safe doors, and is especially applicable to doors for floor safes.

According to the present invention there is provided a safe door incorporating a lock which on operation moves a rack member engaging a toothed wheel, the toothed wheel engaging in turn a rack surface on a reciprocating bolt, whereby operation of the lock in one or another direction causes the bolt to project from or be retracted into the door. In one preferred form, the locking movement, in which the bolt is caused to project from the door, is effected by movement of the rack member behind the inner end of the bolt, thereby providing an abutment to prevent retraction of the bolt unless the rack member is withdrawn in the opposite direction. A spring may be provided to urge the rack towards the abutment position.

Preferably a spring loaded latch is provided which is normally held by the rack member in a retracted condition but which, if the lock is removed from the door, is allowed to move into an extended condition by consequent further travel of the rack member under the influence of its spring, the latch in the extending condition preventing the withdrawal of the rack member from its abutment position. Preferably two toothed wheels are provided, one on each side of the rack member, so that movement of the rack member simultaneously rotates the toothed wheels in opposite directions, the toothed wheels being in engagement with respective bolts which are simultaneously moved thereby into projecting or retracted positions.There is preferably also provided a dead relocking bolt, which is spring loaded into an extended condition but normally held in a retracted condition by the body of the lock, so that if the lock is removed from the door it is sprung into the projecting position. The dead relocking bolt is preferably also provided with a spring loaded latch as described above for retaining it in the extended condition.

In a second preferred form of the invention, said rack member is a further reciprocating bolt having a rack surface, whereby operation of the lock in one or another direction causes both bolts to project from or be retracted into the door.

In order that the invention may be more clearly understood, some embodiments will now be described with reference to the accompanying drawings, wherein: Fig. 1 shows a cross-sectional front view of a floor safe door according to a first embodiment of the invention; Fig. 2 shows a side view of the door of Fig. 1; Figs. 3 and 4 show detailed cross-sectional side views of parts of the mechanism thereof; and Fig. 5 is a view similar to Fig. 1 but showing a floor safe door according to a second embodiment of the invention.

Referring to Figs. 1 to 4; a floor safe door 10 has a circular casing 14 which is flat in side view, and has a projecting rim 12 which abuts the body of the safe around the entrance, the casing lying inside the safe. To the inside surface of the casing is mounted a lock 1 6 which can be of a conventional key operated or combination type. In this embodiment, the lock is of a conventional type which has a reciprocating tongue 1 8 which moves between a retracted position (Fig. 1) and an extended condition (Fig. 2). From the tongue projects a pin 20 which engages in a bore 22 in the side of a rack member 24 which is longitudinally slidable within a radial passage 26 in the casing.The rack member is provided with teeth on opposite sides, and conveniently this is effected by making the rack member from a circular rod and cutting a helical screw 28 on the outside, the screw providing the rack teeth. The rack member engages a pair of toothed wheels 30 which are freely rotatably located on either side of the rack member, and which in turn engage rack surfaces 32 of respective bolts 34 which are located in a diametrical through passage 35 in the casing. The rack surfaces 32 can conveniently be formed as helical screw threads on circular bolts.

The travel of the bolts is limited by pins 36 in the casing projecting into the passage 35 and engaging in rebates 38 in the bolts 34. The bolts are thus allowed to move from an extended condition shown in Fig. 1, in which they project radially from the casing, and a retracted condition in which they are withdrawn within the casing.

This movement is effected by reciprocating movement of the tongue 18 on operation of the lock, which in turn reciprocates the rack member 24, rotating the toothed wheels 30 in opposite directions, and thereby simultaneously retracting or extending the bolts 34. In the extended condition, the rack member 24 moves between the inner ends of the bolts, as can be seen in Fig.

1 , thereby providing an abutment which prevents withdrawal of the bolts unless the rack member is withdrawn. The rack member is urged towards this abutment position by a compression spring 37. Thus, if the lock 1 6 is forcibly removed from the casing, so that the rack member is no longer held in position by pin 20 on the tongue 18, the spring 37 keeps the rack member 24 in the abutment position preventing withdrawal of the bolts 34. Further than this, the radial passage 26 in which the rack member 24 slides allows the rack member, when thus released from the pin 20, to move a little further under the influence of the spring 37. This causes the rack member to move clear of a latching pin 40 which, as can be seen from Fig. 3, is located in a recess 42 in the casing, and is urged by a spring 44 towards the rack member 24.When the rack member moves clear of the pin, the pin projects somewhat into the passage 25 and prevents the rack member from being retracted from its abutment position.

As an additional safeguard there may be provided a dead relocking bolt 46 in a radial passage 48, urged by a spring 50 towards a projecting condition in which it engages an appropriate recess in the safe wall, but which is normally held in a retracted condition by a retaining pin 53 (see Fig. 4) located in a passage 54 in the casing, and having a shank 52 projecting into a bore 56 in the bolt 46. A compression spring 58 around the shank 52 urges the pin 53 outwardly from the casing, tending to disengage the shank from the bolt 46, but the retaining pin is normally held in the engaged position by the body of the lock 16. Thus, if the body of the lock is removed from the casing, the retaining pin flies out, releasing the dead relocking bolt 46.The bolt 46 is then retained in the extended condition by means of a latching pin 40' essentially similar to that shown in Fig. 3 for the rack member 24.

The second embodiment, shown in Fig. 5, has a circular casing 14 behind which is provided a conventional lock mechanism 1 6 as in the first embodiment. Instead of two toothed wheels 30, however, a single, centrally pivoted toothed wheel 60 is provided. Two bolts 62, 64 are provided tangentially to the wheel 60, and are longitudinally slidable in respective passages 66, 68. Both bolts 62, 64 are provided with rack portions provided by helical threadings 32, as in the previous embodiment, and these rack portions co-operate with the toothed wheel 60. Also as previously, the bolts 62, 64 project on opposite sides of the safe door. However, instead of being in line as previously, they are parallel but offset from each other.

Instead of a separate rack member 24 as in the first embodiment, the pin 20 of the lock mechanism 1 6 is located in a bore 70 in the bolt 64. Thus, on operating the lock 16, the pin 20 moves the bolt 64 between a laterally projecting position as shown in Fig. 5 in which it engages a suitable recess in the wall of the safe, and a position in which it is retracted within the casing 14. As the bolt 64 is moved between its projecting and its retracted positions, the toothed wheel 60 rotates and causes the bolt 62 similarly to move between a projecting and a retracted position. In these positions, the safe door is locked or unlocked respectively.

As previously, the movement of the bolts 62, 64 is restricted by means of a pin 36 co-operating with a rebate 38.

Behind each bolt 62, 64 in the passage 66, 68 there is a compression spring 72 which acts to urge the bolt towards its projecting position. Thus, in the event that a thief manages to remove the lock mechanism 16, these springs 72 will push the bolts further into the projecting position, and pin 74, constructed in the same manner as the pin 40 in the first embodiment, will engage behind the bolt to prevent its retraction.

The safe door may optionally be provided with a dead relocking bolt 46, whose operation and construction is exactly the same as described for the first embodiment. Indeed, if desired two such dead relocking bolts may be provided, one above and one below the bolts 62, 64.

The present embodiment has the advantage that it requires fewer moving parts than the first embodiment. Thus, it is cheaper to manufacture. A further advantage is that the bolts 62, 64 are directly urged into the projecting position by the springs 72, rather than through the intermediacy of a toothed wheel, so that if explosives are used in an attempt to open the safe door and the toothed wheel 60 becomes dislodged, the bolts will still be urged into the projecting position.

Claims

1. A safe door incorporating a lock which on operation moves a rack member engaging a toothed wheel, the toothed wheel engaging in turn a rack surface on a reciprocating bolt, whereby operation of the lock in one or another direction causes the bolt to project from or be retracted into the door.

2. A safe door according to claim 1 wherein the locking movement, in which the bolt is caused to project from the door, is effected by movement of the rack member behind the inner end of the bolt, thereby providing an abutment to prevent retraction of the bolt unless the rack member is withdrawn in the opposite direction.

3. A safe door according to claim 2 wherein a spring is provided to urge the rack towards the abutment position.

4. A safe door according to claim 3 wherein a spring loaded latch is provided which is normally held by the rack member in a retracted condition but which, if the lock is removed from the door, is allowed to move into an extended condition by consequent further travel of the rack member under the influence of its spring, the latch in the extended condition preventing the withdrawal of the rack member from its abutment position.

5. A safe door according to any one of the preceding claims wherein two toothed wheels are provided, one on each side of the rack member, so that movement of the rack member simultaneously rotates the toothed wheels in opposite directions, the toothed wheels being in engagement with respective bolts which are simultaneously moved thereby into projecting or retracted positions.

6. A safe door according to claim 1 wherein said rack member is a further reciprocating bolt having a rack surface, whereby operation of the lock in one or another direction causes both bolts to project from or be retracted into the door.

7. A safe door according to claim 6 wherein at least one spring urges the bolts to project.

8. A safe door according to claim 7 wherein a spring loaded latch is provided which is normally held by the rack member bolt in a retracted condition but which, if the lock is removed from the door, is allowed to move into an extended condition by consequent further travel of the rack member bolt under the influence of its spring the latch in the extended condition preventing the retraction of the rack member bolt.

9. A safe door according to any one of the preceding claims having a dead relocking bolt, which is spring loaded into an extended condition but normally held in a retracted condition by the body of the lock, so that if the lock is removed from the door it is sprung into the projecting position.

10. A safe door according to any one of the preceding claims wherein the rack surfaces of the or each bolt and/or of the rack member are provided by a helical screw thread cut on the respective member.

11. A safe door substantially as described herein with reference to and as illustrated in Figs.

1 to 4 or Fig. 5 of the accompanying drawings.