AU673077B2 - Lock mechanism - Google Patents

Description

RECEIVED4 002 3 ECEIVED10 NAY 1995 1 LOCK MECHANISM The present invention relates to improvements in latch and lock mechanisms and in particular to mortice type door locks capable of being operated by at leasy one external operating handle.

Latch and lock mechanisms of the aforementioned kind are well known, however, it is desirable when the mechanism is in a locked condition that the operating handle be capable of rotation through at least a limited arc without providing any strain or force on the latching tongue to try to move same towards a withdrawn position. The present invention aims at providing an arrangement capable of achieving the foregoing performance requirements in a latch or lock mechanism, preferably by use of simple and reliable means.

Accordingly, the present invention provides a latching lock mechanism comprising a latching tongue adapted for movement between an extended latching position and a withdrawn detached position; lock means arranged to selectably hold said latching tongue in said extended latching position when said latch lock mechanism is in a locked condition; latch tongue operation means positionable in at least two different configurations, said latch tongue operation means comprising: a first member for rotational movement about a rotation axis in response to movement of external actuating means, a second member arranged to co-operate with the latching tongue to effect movement of said latching tongue from said extended latching position to said withdrawn detached position upon rotation of said second member about said rotation axis, said first and second members being relatively movable bodily in a lateral direction relative to said axis whereby in a first configuration said first and second members are fixed together for common rotation about said axis and in a second configuration said first member is rotatable independently of said second member; and actuation means provided to move said first and second members to said second configuration when said lock means is arranged in the locked condition.

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RECEIVED 10 MAY 1995 2 In a preferred embodiment, the second member includes an aperture longer in one direction permitting said first and second members to be relatively movable in said lateral direction relative to said rotational axis. Conveniently the first member includes a central boss with the aperture in said second member being located over said central boss. Preferably the aperture is oblong in shape with opposed parallel sides arranged to slide on said central boss when moving between said first and second configurations.

Conveniently the latching lock mechanism includes restraining means to ensure said second member moves in a linear direction when moving between 1 0 said first and second configurations.

In a still further preferred arrangement, the operation means further includes an axially extending projection on one of said first member or said second member, selectably engageable or disengageable with a recess in the other of said first or second members so that said first and second members may be selectably rotated together or alternatively said first member is rotatable independently of said second member.

One particularly preferred embodiment of the present invention is described hereinafter with reference to the accompanying drawings. The drawings illustrate schematically the principal of the present invention with parts omitted fo- the sake of clarity. It will of course also be appreciated that commonly known and used features of lock mechanisms of this kind may be readily incorporated in locks according to the present invention although these will not hereinafter be described as they will be well known to those skilled in this art. In the accompanying drawings Figure 1A is a plan view of a preferred form of lock mechanism according to the present invention; Figure 1B is a perspective view of Figure 1A with some parts omitted for the sake of clarity; Figures 2A/2B, 3A/3B and 4A/4B are views similar to Figures 1A and 1 B showing different positions of the mechanism.

AMENDED SHEET V ~IPENAU PCT/AU 9 4 RECEIVED 1 0MAY 1995 3 Referring now to the drawings, the lock mechanism 10 illustrated comprises a latching tongue member 11 having an outer tongue portion 12 and an inner end 13. The latching member 11 is normally urged outwardly by a spring member (not shown) so that, in use, the tongue portion 1,2 can engage with a latching plate in a door surround or the like. A door operating handle would, in use, be connected to the illustrated mechanism by a square driva bar or shaft engaging both with the handle and with the square drive recess 14 in the mechanism 10. The handle and drive shaft are not shown for the sake of clarity. The position of a key operated lock device 15 is shown in phantom 1 0 outline with the inner end of the lock barrel carrying a plate with a laterally extending tab 16 such that the end of the tab may pass through the arc 17 upon rotation of the lock barrel. In this manner, the tab 16 may engage the inner end AMENDED SHEET

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WO 94125711 PCT/AU94/00223 4 13 of the latching member 11 to withdraw same into the lock housing (not shown) against action of the outwardly urging spring or alternatively, engage a respective one of inwardly directed projections 18,19 on a rear slideable locking bar 20 to thereby position the locking bar in one of two possible positions. The locking bar 20 is restrained to slide in the direction indicated by arrow 21 and a detent mechanism 22 is engageable with a respective one of the recesses 23,24 in the end of the bar 20 so as to releaseably hold the bar 20 in one of the two possible positions. The detent mechanism 22 is stationary apart from inward and outward movement of the end engagement part 25 against or with 1 0 the urging force provided by spring 26 in the dlriction of arrow 27.

At the other end of the locking bar 20 a laterally extending part 28 engages with a mechanism 29 cooperably linking the handle drive recess 14 with the latching tongue member 11. The mechanism 29 comprises a latching tongue operating plate 30 parallel to and adjacent to a handle operating plate 31 with the latter plate 31 also having the square handle drive recess 14 formed therein. The latching tongue operating plate 30 has an extending projection 32 adapted to cooperate with the inner end 13 of the latching tongue 11 to withdraw same inwardly upon rotation of the plate 30 (as shown in Figures 1A/1B). A ecess 33 is formed in the end of the plate 30 opposite to the projection 32, said recess 33 engaging with the laterally extending part 28 so that movement of the bar 20 results in movement of the latching tongue operating plate 30. As an alternative to the arrangement illustrated, it may be possible to arrange a laterally extending projection on the plate 30 engageable with a recess in the bar 20 rather than the reverse shown in the illustrated preferred embodiment.

The latching tongue operating plate 30 is generally constrained to move in a direction parallel to movement of the bar 20 arrow 21). The constraining means may conveniently comprise a plate member 36 (Figure 2A) engageable with the sides 34,35 of the plates 30,31 opposite the bar 20. The plate member 36 is pivotable about a pivot point 37 adjacent the latching tongue member 11 with a spring 38 urging the plate member 36 in a direction so as to try to maintain the position shown in Figure 2A. This enables the WO 94/25711 PCTIAU94/00223 mechanism 29 to pivot as shown in Figure 1A when required but otherwise ensures the plate 30 moves parallel to the direction of movement of the bar Further, the handle operating plate 31 includes a tab or projection 39 bent towards the latching tongue operating plate 30 to cooperate with a recess 40 formed therein. Depending on the position of the plate 30 (after movement via the interaction with the locking bar 20), the tab 39 is either engaged in the recess 40 (as shown in Figures 1A/1B and 2A/2B) or is disengaged therefrom (as shown in Figures 3A/3B and 4A14B). Thus, when the tab 39 is engaged with the recess 40, the plates 30,31 rotate together and when they are disengaged, the handle operating plate 31 will be rotatable separately from the plate Finally, the plate 30 includes a central elongated recess 41 engaged over and slideable on a circular boss 42 forming part of the handle operating plate 31, the boss 42 generally surrounding the square drive recess 14 formed therein. This arrangement permits the plates 30,31 to be relatively moved upon selective 1 5 movement of the locking bar 20 while still allowing the plate 31 to rotate relative to the plate 30 as shown, for example, in Figures 3A/3B.

The arrangement shown in Figures 1A/1B is an unlocked condition where the latch tongue member 11 is withdrawn by engagement of the projection 32 with the inner end 13 of the latch tongue member 11. The plates 30,31 are interengaged so as to rotate together upon rotation of the operating handle (not shown). Figures 2A/2B is also an unlocked condition similar to Figures 1A/1B except that the handle has not been rotated and the latch tongue member is extended to a latching (unlocked) position. In Figures 3A/3B and 4A/4B, the lock bar 20 has been moved to a second detent controlled position where the plates 30 and 31 are relatively moved to disengage the projection 39 from the recess 40 (as shown in Figures 4A/4B). In this condition, rotation of the handle and thereby the plate 31 does not cause rotation of the plate 30 and therefore the member 11 is not capable of being withdrawn.

Claims (6)

1. A latch lock mechanism comprising a latching tongue adapted for movemernt between an extended latching position and a withdrawn detached position; lock means arranged to selectably hold said latching tongue in said extended latching position when said latch lock mechanism is in a locked condition; latch tongue operation means positionable in at least two different conf, .ions, said latch tongue operation means comprising: a first member for rotational movemert about a rotation axis in response to movement of external actuating means, a second member arranged to co-operate with the latching tongue to effect movement of said latching tongue from said extended latching position to said withdrawn detached position upon rotation of said second member about said rotation axis, said first and second members being relatively movable bodily in a lateral direction relative to said axis whereby in a first configuration said first and second members are fixed together for common rotation about said axis and in a second configuration said first member is rotatable independently of said second member; and actuation means provided to move said first and second members to said second configuration when said lock means is arranged in the locked condition.

2. A latching lock mechanism according to Claim 1, wherein said second member includes an aperture longer in one direction permitting said first and second members to be relatively movable in said lateral direction relative to said rotational axis.

3. A latching lock mechanism according to claim 1, wherein said first member includes a central boss with the aperture in said second member being located over said central boss. AMENDED SHE IPENAAU PCT/At 4 3 RECEIVED 1 0 MAT1595 7

4. A 'atching lock mechanism according to claim 3 wherein said aperture is oblong in shape with opposed parallel sides arranged to slide on 1 A central boss when moving between said first and second configurations.

A latching lock mechanism according to any one of claims 1 to 4 further including restraining means to ensure said second member moves in a linear direction when moving between said first and second configurations.

6. A latching lock mechanism according to any one of claims 1 to 5, wherein said operation means further includes an axially extending projection on one of said first member or said second member, selectably engageable or disengageable with a recess in the other of said first or second members so that said first and second members may be selectably rotated together or alternatively said first member is rotatable independently of said second member. PC009400223.WPC[DOC. 049] SKP:EK:BB O A( 4 AMENDED SHEET IPFA/AU