GB2228286A

GB2228286A - Lever dead-locks

Info

Publication number: GB2228286A
Application number: GB8900829A
Authority: GB
Inventors: Edward William Clark
Original assignee: Individual
Current assignee: Individual
Priority date: 1989-01-14
Filing date: 1989-01-14
Publication date: 1990-08-22
Anticipated expiration: 2009-01-14
Also published as: GB2228286B; GB8900829D0

Abstract

A lever deadlock has a bolt 12 having a stump 16 sliding in the gates 23 of a plurality of levers 21 each pivoted on a pin 15. An appropriate key may be inserted in key-hole 19 to move the levers 21 so as to align the gates 23 thereof, whereafter further rotation of the key slides the bolt 12. The lock has a second keyhole 45 in which a master key may be inserted to co-operate with the levers 21, e.g. on edges 47 thereof spaced from the lands 25 engaged by a normal key. Once aligned by the master key, a skeleton key may be used in the keyhole 19 solely to effect movement of the bolt 12. <IMAGE>

Description

DEAD-LOCRS This invention relates to lever-action deadlocks.

A dead-lock has a bolt which is slidably movable between extended and withdrawn positions by means of a key appropriately configured for that lock. A form of lever-action dead-lock has a plurality of pivoted levers spring urged to respective positions where each of the levers obstructs the movement of the bolt. The correct key has a plurality of shoulders, one for each lever, and serves to engage lands on the levers to pivot the levers to positions where the movement of the bolt is no longer obstructed, so that further turning of the key slides the bolt. In a common design of lever-action dead-lock, each lever has an opening which is so-shaped as to define a gate through which an abutment (known as a 'stump') on the bolt passes, as the bolt is slid between its two positions.By configuring the levers differently, the levers have to be moved through different angular extents to align the gates of all the levers and so to permit the stump to pass therethrough, and this requires the use of the correct key for operation of the lock. Such a lock will hereinafter be referred to as a "lever-action dead-lock of the kind described".

Lever-action dead-locks of the kind described may take a variety of forms. For example, such a dead-lock may be constructed as a padlock, where the bolt serves to lock in a closed position a hook mounted on the padlock body. Another possiblity is for such a deadlock to be constructed as a mortice lock, for use for instance on the entrance doors of buildings, including residential properties. Either kind of lock, if having only three levers, gives a relatively low level of security, and so such a lock is often fitted with five or seven levers. Apart from giving greater security, in that the lock becomes more difficult to open other than with the correct key, there is also the added advantage that with more levers, a greater number of key-differs may be provided, for any one particular design of lock.

A disadvantage of five- or seven-lever action dead-locks of the kind described is that though it is possible to provide a master key able to open a number of similar locks which individually require different 'ordinary' key configurations, the number of key differs which may be incorporated with a group of mastered locks is relatively small - typically, at best twelve key differs may be incorporated within a typical five-lever lock design if mastering also is to be achieved. The consequence of this is that where it is essential that a mastering facility be provided for a number of locks but it is also desirable that each lock requires a different 'ordinary' key from the others, lever-action dead-locks with five or seven levers cannot be used. Instead, it is necessary to fit locks offering a lower level of security in order that the mastering may be achieved.For example, in a sheltered housing scheme, it may be desirable to provide each dwelling with a security lock, such as could be achieved with a five-lever dead-lock, but in view of the need to have a mastering facility in a sheltered housing scheme, locks offering lesser security must be used, if there are more than twelve dwellings.

It is accordingly an aim of the present invention to overcome the disadvantage mentioned above, associated with lever-action dead-locks of the kind described.

According to the present invention, there is provided a lever action dead-lock of the kind described, wherein the lock has a second key-access opening disposed to permit a second key to be inserted therein and then to operate the levers by engaging portions thereof spaced from the lands normally engaged by a key inserted in the usual key-access opening, said portions being configured so that when the levers are operated by an appropriate key inserted in the second key-access opening the gates of all the levers are aligned with the path of the bolt stump.

It will be appreciated that in a lock of this invention, the levers of the lock can be moved to align all the gates by means separate from the usual key and lever lands. In this way, the lock bolt is freed so that it may be moved by a 'skeleton' key inserted through the usual key-access opening and which skeleton key is engageable just with the bolt or bolt actuating mechanism. Because, however, the gates and lands of the levers are not modified, the lock is still operable in the conventional manner using the 'correct' key inserted through the usual key-access opening.As a consequence, the number of possible key differs for a given lock design is not changed by providing the means of this invention, and yet each of those locks may be mastered, by an appropriate configuration of the lever portions engaged by the key inserted in the second key-access opening, using a suitable second key, and also using a 'skeleton' bolt-actuating key inserted in the usual key-access opening.

In a lever-action dead-lock of the kind described, the usual configuration is for the levers to be pivoted adjacent one end thereof, and for the usual key access opening to be disposed such that a key inserted therein may co-operate with lands provided on the side edges of the levers, to cause pivoting movement of those levers prior to engaging the bolt, to effect sliding movement thereof. When such a lock is provided with the means of the present invention, the second key access opening may be disposed such that a key inserted therein may engage the ends of the levers opposed to the pivoted ends of those levers.Alternatively, and provided that the levers have sufficient length, the second key access opening may be disposed such that a key inserted therein also engages the same side edges as does the usual key, but at a position spaced along those side edges from the lands contacted by a key inserted in the usual key access opening. A further possibility would be for the levers especially to be extended as required to permit the second key access opening to be disposed clear of the path of movement of the bolt. For example, each lever could be extended on the side thereof opposed to the lands engaged by a key inserted through the usual key access opening, the extended portions of the levers including apertures aligned with the second key access opening, whereby a key inserted therein will be received in those apertures.Then, by appropriate shaping of those apertures and a key for use therewith, the levers may be driven by a key inserted into the second key access opening, so permitting the gates of all of the levers to be aligned with the path of movement of the stump. Then the bolt may be slid, with a skeleton key inserted in the usual key access opening.

By way of example only, one specific embodiment of this invention will now be described in detail, reference being made to the accompanying drawings, in which: Figure 1 is a side view of a lever-action dead-lock, modified in accordance with the invention; Figure 2 is a detail side view on one lever used in the lock of this invention; and Figures 3A, 3B and 3C show three forms of key, for use with the lock of Figure 1.

The lock illustrated in Figure 1 is a modified form of lever-action dead-lock of the kind described and having five levers to control the operation of the bolt. The lock comprises a side plate 10 having an upstanding peripheral wall 11, there being a further side plate (not shown in the drawings, for clarity) adapted to fit over the peripheral wall 11, parallel to plate 10. The lock includes a bolt 12 having a head 13 mounted on a tail 14, the tail having an elongate guide slot (not shown) in which is received a pivot pin 15.

Upstanding from the tail 14 is a stump 16. The bolt 12 also includes a talon (not shown) engageable by lobe 17 of a rotatable curtain 18, to effect sliding movement of the bolt 12 between withdrawn and projecting positions. The curtain 18 is mounted on the side-plate 10 for rotation about the axis of a principal keyhole 19, and rotation of that curtain is resisted by a spring 20 other than when a key is used positively to turn that curtain.

Pivoted on pin 15 are five levers 21, arranged side-by-side - and consequently only one of those levers is properly visible in Figure 1. Each lever has an aperture 22 in which is received the bolt stump 16, and each aperture 22 defines a narrow gate 23 through which the stump 16 must -pass, when the bolt is slid between its two limiting positions - i.e. withdrawn and projecting. Each lever has associated therewith a spring 24, to bias the lever in a counter-clockwise direction, as viewed in Figure 1.The position of the gate in each lever relative to the lower edge 25 of the lever is different for at least some of the levers, whereby the amount that each lever has to be pivoted in a clockwise sense, against the action of the respective spring 24, is different - and such pivoting action of the levers is performed by a key (such as that shown in Figure 3A) inserted into the principal key access opening 19.

Referring to Figure 3A, there is shown part of a key intended for use with the lock of Figure 1. When the key is inserted into the principal key access opening 19 in side plate 10 (i.e. from below, as viewed in Figure 1) shoulders 30 and 31 lie within the thickness of the curtain 18 and serve to drive the bolt 12; shoulders 32 to 36 inclusive operate the levers by engaging the lands 27 on the side edges 25 of the levers, whereby those levers are pivoted to the required extent to align all of the gates 23 therein.

When so aligned, the stump 16 may be able to pass therethrough. If the key of Figure 3A is inserted into the lock from the opposite side thereof, then shoulders 30 to 34 inclusive operate the levers, and shoulders 35 and 36 lie within the confines of the curtain 18.

The lock illustrated in Figure 1 further includes a latch plate 40 and associated spring 41, together with an operating cam 42; these parts are entirely conventional and form no part of this invention and thus will not be described further here.

The lock thus far described is essentially conventional in its construction and the operation thereof is well known and understood in the art. The lock has however been modified to permit a form of mastering to be achieved, whereby the lock may be opened other than with the key illustrated in Figure 3A. This modification includes the position of a second key-access opening 45 in both side plates of the lock.

The tail 14 of the bolt 12, has an aperture 46 formed therein, to permit a key to be inserted into the second key-access opening 45, which access opening is disposed in the region of the lock adjacent the ends of the levers 21 opposed to pivot pin 15. The end edge 47 of each lever opposed to pivot pin 15 is specially formed and shaped so as to permit pivoting movement of that lever by means of a second key inserted in the second key-access opening 45. In this way, and provided the key is appropriately formed, all of the levers may be pivoted to the extents required to align the gates of the levers with the line of movement of the stump 16. In Figure 2, showing one of the levers 21, the shape of the lever as used in a conventional lock is shown in broken lines, but the lever as modified for use in the lock of Figure 1 is shown in full lines.It can be seen that a nose-piece 48 has been added to the original lever of the lock, which nose-piece 48 has a shaped end edge 47 with which the key co-operates.

Figure 3B shows a key suitable for use in the second key access opening 45. It can be seen that this key has five shoulders disposed between outer abutments, one shoulder for each lever respectively and of such a height, having regard to each lever, that the levers will be lifted to the required extent when the key is inserted into the second key access opening, and turned in a counter clock-wise sense (in Figure 1).

Figure 3C shows a further key for use in conjunction with the key of Figure 3B, but in the principal key access opening 19. Once the key of Figure 3B has been used to lift the levers to align the gates thereof, the key of Figure 3C may be inserted into the principal key access opening 19 to turn the curtain 18, so as thereby to commence the withdrawing action of the bolt 12. Once the stump 16 has entered the aligned gates 23, the key of Figure 3B is removed from the second key access opening, and then the withdrawal of the bolt is completed using the key of Figure 3C.

It will be seen that the lock described above may employ a very large number of key differs for the principal key used in the key access opening 19, whereby a large number of individual locks may be furnished. However, by appropriate configuration of the nose pieces added to the levers, all of those locks may be opened by a single key (Figure 3B) inserted in the second key access opening 45, and which key is used in conjunction with a skeleton key as illustrated in Figure 3C.

Claims

1. A lever action dead-lock of the kind described, wherein the lock has a second key-access opening disposed to permit a second key to be inserted therein and then to operate the levers by engaging portions thereof spaced from the lands normally engaged by a key inserted in the usual key-access opening, said portions being configured so that when the levers are operated by an appropriate key inserted in the second key-access opening the gates of all the levers are aligned with the path of the bolt stump.

2. A lever-action dead-lock according to claim 1, wherein the levers are pivoted adjacent one end thereof, and the usual key-access opening is disposed such that a key inserted therein my co-operate with land provided on the side edges of the levers to ause pivoting movenent of those levers prior to the key engaging the bolt to effect sliding movement thereof, the second key-access opening being disposed such that a key inserted therein will engage the ends of the levers opposed to the pivoted ends thereof.

3. A lever-action dead-lock according to claim 1, wherein the levers are pivoted adjacent one end thereof, and the usual key-access opening is disposed such that a key inserted therein may co-operate with lands provided on the side edges of the levers to cause pivoting movement of those levers prior to the key engaging the bolt to effect sliding movement thereof, the second key-access opening being disposed such that a key inserted therein will engage the same side edges of the levers as have formed thereon the lands engaged by a correct key inserted in the usual key-access opening.

4. A lever-action dead-lock according to claim 1, wherein the levers are pivoted adjacent one end thereof, and the usual key-access opening is disposed such that a key inserted therein may co-operate with lands provided on the side edges of the levers to cause pivoting movement of those levers prior to the key engaging the bolt to effect sliding movement thereof, the second key-access opening being disposed to overlie the levers, each lever being provided with an opening in register with the second key-access opening and each opening defining an edge engageable by z key inserted in the second key-access opening to effect alignment of the lever gates.

5. A lever-action deadlock according to any of the preceding claims, wherein there is provided a skeleton key insertable in the usual key-access opening to effect movement of the bolt following operation of the levers by a suitable key inserted int6 the second keyaccess opening.

6. A lever-action deadlock according to any of the precediny claims, whenever constructed as a mortice deadlock.

7. A lever-action deadlock according to claim 6, wherein the lock is provided with a spring-urged latch plate together with an operating mechanism therefore.

8. A lever-action deadlock of the kind described and substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.

9. A lever-action deadlock according to any of claims 1 to 5, whenever constructed and arranged as a padlock including a body and a hook movably mounted on the body and lockable in a closed position by the lock mechanism.