GB2261696A - Key operated warded lock - Google Patents

Abstract

A key operated warded lock has a ward bushing (52) mounted within the lock casing in non rotatable relationship to the keyhole. The bushing (52) is fully machined to its desired final profile before assembly with the lock mechanism. The bushing (52) is supported on a cylindrical key guide (32) and the bushing includes flat edges (60) engageable with correspondingly shaped parts of the keyhole to provide said non-rotatable relationship therewith. <IMAGE>

Description

Title: Key Operated Lock This invention relates to a warded lock of the type having a profiled ward permitting rotation of a correspondingly profiled key relative thereto to move a lock bolt between locked and unlocked positions.

It has been the practice to rivet or swage or otherwise secure a solid or part pierced, unmachined, or part machined ward blank to a cover plate of a lock casing and thereafter to pierce and/or machine the blank in situ on the cover plate. The ward blank has conventionally been formed of brass. Such riveting or swaging and machining operations carried out in situ are inaccurate, inefficient and add unnecessary production cost to the manufacture of locks.

It is an object of the present invention to provide a new or improved construction of warded lock.

In accordance with the invention there is provided a key operated warded lock comprising a lock casing containing a lock mechanism, a wall of said casing having a keyhole therein with a ward associated with said keyhole, said ward having a profile engagable by a correspondingly profiled part of a key whereby the key may be rotated relative to the ward for actuating the lock mechanism characterised in that the ward comprises a bushing of a desired profile detachably secured to said wall in non-rotatable engagement therewith.

Also in accordance with the invention there is provided a method of manufacturing a key operated warded lock including the steps of producing a ward as a bushing machined to a desired profile and locating said machined ward bushing in non-rotatable relationship to a keyhole provided in a wall of a casing for the lock mechanism.

Conveniently the ward bushing is supported non-rotatably relative to said wall by support means within said casing, said support means conveniently comprising key guide means rotatable with a key relative to said ward bushing.

The lock conveniently comprises a lever lock of the type wherein a plurality of levers are engagable by the key upon rotation thereof relative to the ward bushing to move the levers to positions in which a lock bolt may be driven directly or indirectly by the key between locked and unlocked positions, the levers being spring biased to block movement of the lock bolt when the key is disengaged from contact with the levers.

The key guide means conveniently comprises a generally cylindrical member having an axially extending slot therein through which the key bit may extend radially when the key is inserted axially through the keyhole and into the guide. The ward bushing is conveniently mounted on a shoulder on said cylindrical member and such shoulder may comprise a part annular shoulder provided on the exterior of said cylindrical member and extending circumferentially therearound between the edges of the said slot.

The ward bushing may be provided with an internal part annular shoulder whereby the bushing may be supported on said exterior shoulder of the key guide.

The ward bushing conveniently includes a part annular generally cylindrical portion for engagement with a correspondingly shaped part of the keyhole in the said wall. The ward bushing includes an axially extending slot aligned with the remainder of the keyhole whereby the bit of a key may extend radially through said slot when the key is inserted into the keyhole.

The said generally cylindrical portion of the ward bushing may include one or more flat edges engagable with one or more corresponding flat edges of the keyhole whereby the ward bushing is locatable non-rotatably relative to the keyhole. The ward bushing may be located non-rotatably relative to the keyhole by other suitable means; for example the said generally cylindrical portion may be replaced by a portion of non-circular cross-sectional form engagable with a correspondingly shaped part of the keyhole. The ward bushing may be secured to the said wall by fastener means or by means of an adhesive in which cases it is not essential that the bushing is supported internally of the cover plate.

The bushing may be formed of brass and is fully machined to its final desired profile before assembly with the lock.

The said key guide means may be formed integral with, or secured to, a rotor carrying a thrower for engagement with the lock bolt for driving the bolt between its locked and unlocked positions when so permitted by the lock levers in response to engagement therewith by the key. Said support means preferably includes location means for locating and retaining the support means in a predetermined angular orientation relative to the keyhole. Conveniently said location means comprises a notch or detent engagable with spring means secured to the lock casing and said notch or detent may be provided on said thrower rotor or on said key guide means.

The said wall of the lock casing to which a ward is non-rotatably assembled may comprise a cover plate of the casing and/or a back plate thereof.

Other features of the invention will become apparent from the following description given herein solely by way of example with reference to the accompanying drawings wherein: Figure 1 is a somewhat diagrammatic cutaway perspective view of the interior of a mortice lever lock constructed in accordance with the invention; Figure 2 is a cross-sectional view through a cover plate of the lock showing the leading end of a key bit engaged with the ward bushing; Figure 3 is a diagrammatic top plan view of the lock mechanism with the cover plate removed showing the key in a neutral position and the lock bolt in its retracted unlocked position; and Figure 4 is a similar top plan view to that of Figure 3 but showing the key rotated to a position in which the lock bolt is in its extended locked position.

As described and illustrated herein, a lock constructed in accordance with the invention comprises a key operated mortice lever lock. Locks of this general type are known in the art and typically comprise a sliding deadbolt 10 movable between an extended locked position and a retracted unlocked position either directly by means of a key or indirectly by a rotatable thrower 12 operated by the key. The bolt 10 is mounted for sliding movement on a back plate 14 of a lock casing and the bolt 10 may conventionally include a square peg, or stump; (not illustrated) on that face of the bolt lath adjacent the internal face of the back plate 14 with said peg sliding within a blind ended rectangular recess whereby abutment of the peg at each end of the recess limits the sliding travel of the bolt between its fully extended and fully retracted positions.

The other face of the bolt 10, i.e. the upper face as illustrated in Figure 1, has a further upstanding peg or stump 16 of generally rectangular cross sectional form which extends upwardly through a gating system defined by a set of levers 18 arranged in a stack as shown in Figure 1. Each lever is provided with an H-shaped gate comprising two substantially square end apertures 20 connected by a rectangular thinner aperture 22 (see Figures 3 and 4). Each lever 18 is mounted for sliding movement on two pins 24 secured to and extending upwardly from the interior face of the back plate 14, each lever having slots 26 engaging the pins 24 guiding the levers for sliding movement relative to the casing.A leaf spring 28 is secured to each lever 18 and bears at its free end on a fixed abutment 30 whereby each lever is spring biased to the position shown in Figure 1 with the ends of the slots 26 abutting the respective pins 24.

The lock is operated in this example by means of a rotary thrower 12 provided integral with a generally cylindrical key guide 32. The thrower 12 comprises a disc having a central aperture to receive the shank of a key and a parallel sided radial slot 34 extending from said aperture to receive the key bit.

At the radially outer end of the radially extending slot 34 there are provided a pair of opposed parallel upstanding flanges 36 comprising the thrower proper and which are engagable, upon rotation of the thrower 12, in a recess 38 provided in an adjacent side edge of the bolt lath. Such drive recess is of conventional form comprising a rectangular part and opposed arcuate entry parts for reception of the said flanges 36. The thrower disc is provided in its outer periphery with a Vshaped notch 40 engagable by a leaf spring 42 mounted on the casing as is clearly visible in Figures 3 and 4 thereby to locate the thrower 12 with its radial slot 34 in alignment with corresponding aligned keyhole slots in the lock casing back plate 14 and the lock cover plate 44.

Extending upwardly from the thrower disc there is provided an integral key guide 32 comprising a part annular generally cylindrical barrel having a part cylindrical internal wall and a slot 46 extending axially thereof through which the key bit 48 may extend as can be seen from Figures 2, 3 and 4. The upper end of the barrel 32 is of reduced thickness cross section providing an exterior annular shoulder 50 providing a locating and bearing surface for a ward bushing 52 constructed in accordance with the invention as will be further described below.

The said ward bushing 52 is of generally part cylindrical configuration comprising an upper generally cylindrical portion 54 engagable within a generally cylindrical aperture part of the keyhole slot in the lock cover plate 44 and a further cylindrical portion 56 which is machined to a predetermined profile for engagement by either the leading or trailing profiled end faces of the key bit depending upon the direction in which the key is inserted into the lock. As will be clearly seen from Figures 1, 3 and 4, the ward is formed with an axially extending slot 58 through which the key bit may pass. The upper cylindrical portion 56 of the ward bushing 52 is machined to provide a pair of aligned planar faces 60 whereby the ward bushing may be located in non-rotatable engagement within a correspondingly shaped aperture part of the keyhole slot in the cover plate 44.A shoulder formed internally of the ward bushing enables it to be mounted on and supported by the annular shoulder 50 provided on the key guide barrel 32.

Thus, when assembled, the ward bushing 52 is maintained in position by the key guide barrel 32 and by the engagement of the ward bushing in a nonrotatable manner with the lock cover plate 44. As shown in Figure 2, when a key is inserted from the lock casing side of the lock it is the leading end profile of the key bit 48 which engages a corresponding profile of the ward bushing thereby enabling the key to be rotated relative to the stationary ward bushing to cause the key guide barrel 32 and thrower 12 to rotate with the key. Conversely, a key may be inserted into the lock from the cover plate side thereof in which case it is the key bit profile at its trailing end which will be engagable with the correspondingly profiled part of the ward bushing to permit rotation of the key relative thereto.

Rotation of the key and thrower enables operation of the lock to be accomplished in known manner. Upon rotation of the key from the positions shown in Figures 1 and 3 in a counter-clockwise direction, the key will engage the levers 18 to align the centre apertures 22 of the H-shaped gates subsequent to which, upon further rotation of the key, the flanges 36 of the thrower will enter into and engage the bolt recess 38 and drive the bolt positively from its retracted position towards its extended position.When the bolt has been fully driven to its extended position as shown in Figure 4, continued rotation of the key will disengage the flanges 36 from the bolt recess 38 at which time the levers 18 will be spring biased back towards their original positions closing the gating system against any forced retraction of the bolt since the stump 16 thereof will then be engaged within the leading end apertures 20 of the H-shaped gates in each lever.

Further rotation of the key will bring the key guide barrel 32 and thrower 12 back to the initial or neutral position as shown in Figures 1 and 3 at which time the key can be removed from the lock.

In prior art locks of the warded type, the ward has been made of a circular piece of metal, conventionally brass, which has then been machined to a required profile after being fixed in the lock cover plate or, in some more expensive forms of locks, in both the cover plate and the lock casing back plate around the keyhole aperture. Such an in situ machining operation is time consuming and expensive and, furthermore, should such a lock be damaged or a key lost, it would be necessary to replace the entire lock. Conversely, in a lock constructed in accordance with the present invention, the ward is provided as a separate bushing which is machined to the required profile before being assembled with the remainder of the lock. Such a separate premachining operation is a more economical method of producing a warded lock and additionally enables the replacement of a ward bushing quite independently of any other part of the lock mechanism should the ward become damaged or a key be lost.

The features disclosed in the foregoing description, or the accompanying drawings, expressed in their specific forms or in terms of a means for performing the disclosed function, or a method or process for attaining the disclosed result, as appropriate, may, separately or in any combination of such features, be utilised for realising the invention in diverse forms thereof.

Claims (21)

1. A key operated warded lock comprising a lock casing containing a lock mechanism, a wall of said casing having a keyhole therein with a ward associated with said keyhole, said ward having a profile engageable by a correspondingly profiled part of a key whereby the key may be rotated relative to the ward for actuating the lock mechanism characterised in that the ward comprises a bushing of a desired profile detachably secured in said casing in non-rotatable relationship to said keyhole.

2. A lock as claimed in claim 1 wherein said ward bushing is supported by support means in said casing in said non-rotatable relationship to said keyhole.

3. A lock as claimed in claim 2 wherein said support means comprises key guide means rotatable with a key relative to said ward bushing.

4. A lock as claimed in claim 3 wherein said key guide means comprises a generally cylindrical member having an axially extending slot therein through which the key bit may extend radially when the key is inserted axially through the keyhole into said cylindrical member.

5. A lock as claimed in claim 4 wherein said ward bushing is mounted on a shoulder on said cylindrical member.

6. A lock as claimed in claim 5 wherein said shoulder comprises a part annular shoulder provided on the exterior of said cylindrical member and extending circumferentially therearound between the edges of said slot.

7. A lock as claimed in claim 6 wherein said ward bushing is provided with an internal part annular shoulder for supporting the bushing on said exterior shoulder on said cylindrical member.

8. A lock as claimed in any one of the preceding claims wherein said ward bushing includes a part annular cylindrical portion for engagement with a correspondingly shaped part of the keyhole in said wall.

9. A lock as claimed in claim 8 wherein said cylindrical portion of the ward bushing includes one or more non-circular portions engage able with one or more corresponding non-circular portions of said keyhole for locating the bushing in non-rotatable relationship to said keyhole.

10. A lock as claimed in claim 9 wherein said one or more non-circular portions comprise one or more flat edges.

11. A lock as claimed in any one of the preceding claims wherein said ward bushing is secured to said wall adjacent said keyhole by adhesive means.

12. A lock as claimed in any one of claims 1 to 10 wherein said ward bushing is secured to said wall adjacent said keyhole by mechanical fastener means.

13. A lock as claimed in any one of claims 3 to 7 wherein said key guide means includes a rotor carrying a thrower for engagement with a lock bolt for driving the bolt between locked and unlocked positions thereof.

14. A lock as claimed in any one of claims 2 to 7 wherein said support means includes location means for locating and retaining said support means in a predetermined angular orientation relative to said keyhole.

15. A lock as claimed in claim 14 wherein said location means comprises a notch or detent on said support means engageable with spring means secured to the lock casing.

16. A lock as claimed in any one of the preceding claims wherein said ward bushing is formed of brass and is fully machined to its final desired profile before assembly with the lock.

17. A lock as claimed in any one of the preceding claims wherein said wall of the lock casing comprises either a cover plate or a back plate of the casing.

18. A lock as claimed in any one of the preceding claims comprising a lever lock of the type wherein a plurality of levers are engageable by a key upon rotation thereof relative to said ward bushing to move the levers to positions at which a lock bolt may be driven directly or indirectly by the key between locked and unlocked positions, the levers being spring biased to block movement of the lock bolt when the key is disengaged from the levers.

19. A method of manufacturing a key operated warded lock including the steps of producing a ward as a bushing machined to a desired profile and locating said machined ward bushing in non-rotatable relationship to a keyhole provided in a wall of a casing for the lock mechanism.

20. A key operated warded lock constructed and arranged substantially as hereinbefore described with reference to the accompanying drawings.

21. Any novel feature or novel combination of features described herein and/or in the accompanying drawings.