GB2143888A - Security device for a closure - Google Patents

Abstract

A security device has a primary latch bolt (11) movable between extended and retracted positioning by operation of a handle (14) between a rest position (14a) and a first operative position (14b). Secondary latch bolts (20) are also movable between extended and retracted positions by operation of the handle (14) between said rest position (14a) and first operative position (14b). The handle is also movable into a second operative position (14c) to move the secondary latch bolts (20) into a further condition in which they are extended beyond said second condition. In this, further extended, position the chamfers (35) on bolts (20) engage rounded surfaces on the keepers (36) to force the closure (17) tightly shut. As shown the primary latch (11) and a dead-bolt (12) may be operated by a conventional device (13) with a handle adapted to move bolts (20) by the pin-and-slot, lost motion connections involving levers 27. <IMAGE>

Description

SPECIFICATION Security device for a closure This invention relates to a security device for a closure.

According to the invention, such a security device comprises a primary latch bolt which can be moved between extended and retracted conditions by manual operation of a handle between a rest position and a first operative position, and at least one secondary latch bolt which is also moved between extended and retracted conditions by operation of the handle between said rest and first operative positions, the handle also being movable into a second operative position to move the or each secondary latch bolt into a further condition wherein it is extended beyond said second condition.

Preferably, lost motion is provided between the handle and the or each secondary latch bolt so that the handle can be moved from said second operative position to said rest position while the or each secondary latch bolt remains in said further condition, the or each secondary latch bolt subsequently being moved into its retracted condition by movement of the handle from said rest position to said first operative position.

Desirably, the handle moves the or each secondary latch bolt by means of a pivotable operating member which bears against a cam surface on said bolt.

Advantageously, the primary and secondary latch bolts are provided with chamfered tongues with the chamfers all facing in the same direction, and the or each secondary latch bolt has a further chamfer which faces in the opposite direction and which becomes engaged with an abutment only when said bolt is in its further condition.

Conveniently, the second operative position of the handle is disposed on the opposite side of the rest position from the first operative position thereof.

The primary latch bolt preferably forms part of a locking device which also includes a deadbolt which can be locked in an extended condition, such locking of the dead bolt also being effective to lock the or each secondary latch bolt in said further condition.

The invention will now be further described, by way of example only, with reference to the accompanying drawings, in which: Figure 1 is an exploded view, partly broken away, of a security device according to the present invention; Figure 2 is a plan view of part of the security device; and Figures 3 to 7 are schematic views of the security device illustrating various stages in its operation.

Referring first to Fig. 1, there is shown a generally conventional mortice lock 10 which includes a primary latch bolt 11 and a deadbolt 1 2. The latch bolt 11 can be extended and retracted relative to a casing 1 3 by means of a manually operable lever handle 14 by way of a square-section spindle 15, while the deadbolt 1 2 can be extended and retracted by key operation of a lock unit 1 6.

The latch bolt 11 is biassed into its extended condition, and occupies this condition when the handle 14 is in a generally horizontal rest position (designated 1 4a). The latch bolt 11 can be retracted against the action of its spring bias by moving-the handle 14 downwardly into a first operative position 14b, indicated by chain-dotted lines.

The lock 10 is recessed into an edge of a closure 1 7 (such as an aluminium-framed door) in use. Provided at positions adjacent to the top and bottom of this edge of the closure are subsidiary bolt units 1 8 and 19, each of which includes a secondary latch bolt 20. As will now be explained in detail, these bolts 20 are also capable of being extended and retracted relative to respective casings 21 by movement of the handle 14 between its positions 1 4a and 14b. More particularly, an operating plate 22 receives the spindle 1 5 through a square-section aperture 23 so that it rotates with the handle 14. At diametrically opposed positions thereon, the plate 22 is provided with a pair of slots 24, each of which slidably receives a pin 25 provided on one end of a respective elongate link 26.At its other end, each link 26 is coupled to a Vshaped lever 27 pivotally mounted in the casing 21 of a respective one of the bolt units 18 and 19, such coupling being by means of a pivot pin 28 which is movable along an arcuate slot 29 in the casing 21. The lever 27 has a bent-over flange 30 which engages an inclined cam surface 31 on the respective secondary latch bolt 20. Reference numeral 32 denotes a spring which biasses the latch bolt 20 into an extended condition, while reference numeral 33 designates a pin and slot arrangement for guiding the bolt 20 in its extending and retracting movement relative to the casing 21.

When the handle 1 4 occupies its rest position 1 4a, the bolts 20 are in their extended conditions, and the pins 25 on the links 26 engage ends of the respective slots 24 in the anticlockwise direction, as viewed in Fig. 1.

When the handle 14 is moved downwardly into the position 1 4b, the engagement between the pins 25 and the slot ends causes the links 26 to move in the directions indicated by arrows A, thereby pivoting the levers 27 and causing the flanges 30 to bear against the cam surfaces 31 and thereby retract the bolts 20 against the action of the springs 32.

When the handle 1 4 is subsequently returned to its rest position 14a, the springs 32 return the bolts 20 to their extended conditions.

Each of the latch bolts 11 and 20 has a tongue with a chamfered surface 34 which engages a respective staple fixed to a frame surrounding the closure when the closure is shut and the bolts are extended. All of the chamfered surfaces face in the same direction, i.e. in the direction in which the closure is shut, so that the bolts can engage the staples as the closure is shut without the need to operate the handle 14, in an entirely conventional manner. As can be seen in Fig. 2, however, each of the secondary latch bolts 20 also has a subsidiary chamfered surface 35 which faces in the opposite direction.In the normal extended condition of the bolt 20, this surface 35 does not protrude beyond the edge of the closure 1 7. However, as will now be explained, by a special operation of the handle 14 a further extension of the bolt 20 can be obtained to bring the surface 35 into engagement with the respective staple (referenced 36 in Fig. 2), whereby the closure can be held in a properly shut condition despite any distortions which may be present.

Referring back to Fig. 1, if the handle 14 is moved upwardly from its rest position 1 4a into a second operative position 1 4c (shown in chain-dotted lines), initially there is no movement of the bolts 20 as the pins 25 move along the slots 24 in the operating plate 22. However, as soon as the pins 25 engage the opposite ends of the slots, continued movement of the handle 14 pivots the levers 27 so as to engage a further bent-over flange 37 thereon with a rear end of the bolt 20, thereby urging the bolts 20 beyond their normal extended conditions into a further extended condition, as indicated in broken lines in Figs. 2. This in turn brings the chamfered surfaces 35 on the bolts 20 ito engagement with rounded surfaces 38 on the staples 36, thereby urging the top and bottom portions of the closure into a tightly shut condition.In Fig. 2, the spacing between the bolt 20 and the staple 36 is shown greatly exaggerated for the purpose of clarity.

Once the bolts 20 have been further extended as described above, the lost motion provided on the one hand by the pin and slot connections between the operating plate 22 and the links 26, and on the other hand between the levers 27 and the bolts 20, allows the handle 14 to be returned to its rest position 1 4a without the bolts 20 being retracted. The bolts 20 can however be retracted simply by moving the handle 14 into the position 1 4b, thereby causing the flanges 30 on the levers 27 to act on the inclined cam surfaces 31 on the bolts 20.The cam surfaces 31 are specifically configurated on the one hand to prevent the bolts 20 from being retracted when the handle 14 is moved to its rest position 1 4a from the operating position 1 4c, and on the other hand to permit the bolts 20 to be fully retracted from their further extended condition by movement of the handle 14 from the rest position 1 4a to the operating position 1 4b whilst allowing the bolts 20 to be extended normally when the handle is subsequently returned to its rest position.

The above-described sequence of operations can be summarised as follows with reference to Figs. 3 to 7. During normal operation, the latch bolts 11 and 20 are extended when the handle 14 occupies its rest position (Fig. 3).

In order to extend the latch bolts 20 further, the handle is raised (Fig. 4). The latch bolts 20 then remain in their further extended condition when the handle is returned to its rest position, whereupon the lock 1 6 can be operated to extend the deadbolt 1 2 (Fig. 5). An interlock is preferably provided which prevents any of the latch bolts 11 and 20 from being retracted until the dead bolt 1 2 is first withdrawn from its extended condition. In order to retract the latch bolts 20 from their further extended condition, the handle is moved downwardly from its rest position, which action also retracts the latch bolt 11 (Fig. 6).

Finally, all three latch bolts are returned to their normal extended condition when the handle is returned to its rest' position (Fig. 7).

Although not specifically illustrated, springs are provided to bias the handle 1 4 into its rest position 1 4a from both of the operating positions 14b and 14c.

In a typical example of the invention, the security device is mounted on a closure which is 2m tall, the bolt units 18 and 1 9 each being provided approximately 200mm from the top or bottom of the closure, as the case may be. Each of the latch bolts 20 protrudes 11 mm from the edge of the closure 1 7 when in its normal extended condition, and is extended by a further 6mm upon lifting the handle 14 from its rest position. The chamfered surface 35 stands 3mm proud from each bolt 20, so that distortions of up to this amount can be corrected by moving the bolts into their further extended condition.

Claims (14)

1. A security device comprising a primary latch bolt which can be moved between extended and retracted conditions by manual operation of a handle between a rest position and a first operative position, and at least one secondary latch bolt which is also moved between extended and retracted conditions by operation of the handle between said rest and first operative positions, the handle also being movable into a second operative position to move the or each secondary latch bolt into a further condition wherein it is extended beyond said second condition.

2. A security device according to Claim 1 wherein lost motion is provided between the handle and the or each secondary latch bolt so that the handle can be moved from said second operative position to said rest position while the or each secondary latch bolt remains in said further condition, the or each secondary latch bolt subsequently being moved into its retracted condition by movement of the handle from said rest position to said first operative position.

3. A security device according to Claim 1 or Claim 2 wherein the handle moves the or each secondary latch bolt by means of a pivotable operating member which bears against a cam surface on said bolt.

4. A security device according to any one of the preceding claims wherein the primary and secondary latch bolts are provided with chamfered tongues with the chamfers all facing in the same direction, and the or each secondary latch bolt has a further chamfer which faces in the opposite direction and which becomes engaged with an abutment only when said bolt is in its further condition.

5. A security device according to any one of the preceding claims wherein the second operative position of the handle is disposed on the opposite side of the rest position from the first operative position thereof.

6. A security device according to any one of the preceding claims wherein the primary latch bolt forms part of a locking device which also includes a deadbolt which can be locked in an extended condition, such locking of the deadbolt also being effective to lock the or each secondary latch bolt in said further condition.

7. A security device according to Claim 2 wherein the handle is connected to the or each secondary latch bolt by a respective link and said lost motion is provided by a pin and slot connection between each link and means rotatable with the handle.

8. A security device according to Claim 7 when dependent upon Claim 3 wherein each said operating member is a two-armed lever pivotally mounted on a casing of the associated secondary latch bolt and each link is coupled, at a location spaced from said pin and slot connection, to a respective operating member by means of a pivot pin movable along an arcuate slot of said casing.

9. A security device according to Claim 8 wherein each secondary latch bolt is guided for movement between its extended and retracted positions relative to said casing by a pin and slot arrangement.

10. A security device according to any one of the preceding claims wherein each secondary latch bolt is biassed towards its extended condition.

11. A security device according to any one of Claims 8 to 10 wherein each link is connected to one arm of its associated lever, the other arm of each lever bearing against a cam surface on the associated secondary latch bolt.

1 2. A security device substantially as hereinbefore described with reference to Figs.

1 and 2 of the accompanying drawings.

1 3. A closure incorporating a security device according to any one of the preceding claims.

14. A closure according to Claim 1 3 and substantially as hereinbefore described with reference to Figs. 3 to 7 of the accompanying drawings.