GB2310685A - Reversable latch - Google Patents

Abstract

A mortice latch wherein the connection between the latch bolt 16 and the latch lath 24 comprises a shaft 20 fixed to one of the said elements and which is slidably and rotatably received in an aperture in the other opposite element, there being resilient biasing means 30 to bias the latch bolt and the latch lath together in a so as normally to dispose a portion of the latch bolt within the aperture in the fore-end of the lock casing when the latch lath is in its extended position and whereby the latch bolt may be manually displaced outwardly of the aperture in the fore-end and then rotated to change the hand followed by release of the latch bolt so as to be biased inwardly of the case so as to again position a portion of the latch bolt within said aperture. The bolt may be aligned in the case aperture by flanges 62 engageing in alternative pairs of slots (63) fig 2 (not shown).

Description

Title: Latch Description of the Invention This invention relates to a mortice latch, hereinafter referred to as being "the kind described", comprising a case having a fore-end, an asymmetric latch bolt slidable in an aperture in the fore-end between an extended position in which the latch bolt projects outwardly of the fore-end and a retracted position, an operating member moveable to retract the latch bolt from said extended position to said retracted position, the latch bolt being carried on a latch lath slidably mounted in the case and which is movable by the operating member to cause said retraction of the latch bolt.

It is frequently desired to be able to use a mortice latch in a "handed" situation in which the latch bolt can be disposed in a selected one of two positions usually at 1800 to each other. Hitherto it has been necessary to disassemble the case and re-mount the latch bolt on the latch carrier in an orientation suitable for the hand required where this has not matched the hand of the lock as manufactured.

An object of the present invention is to provide a mortice latch whereby the above-mentioned problem is overcome or reduced.

According to the present invention we provide a mortice latch of the kind described wherein the latch bolt comprises means enabling it to be handed.

The connection between the latch bolt and the latch lath may comprise a shaft fixed to one of the said elements and which is slidably and rotatably received in an aperture in the other opposite element, there being resilient biasing means to bias the latch bolt relative to the latch lath in a direction inwardly of the case so as normally to dispose a portion of the latch bolt within the aperture in the fore-end when the latch lath is in its extended position and whereby the latch bolt may be manually displaced outwardly of the aperture in the fore-end and then rotated to change the hand followed by release of the latch bolt so as to be biased inwardly of the case so as to again position a portion of the latch bolt within said aperture.

The latch shaft may be fixed to the latch bolt and slidably received within an aperture of the latch lath.

The latch lath may be provided with an upstanding lug extending perpendicular to the direction of movement of the latch lath in which said aperture is provided.

A coil compression spring may be disposed between a side face of the lug and an abutment provided on the latch shaft.

The latch bolt may comprise guides which may be received into a desired one of a pair of guide means.

The guide means may be provided in the fore-end.

The guide means may comprise ribs disposed lengthwise of the latch bolt and the guide means may comprise grooves into which the ribs are received.

The latch bolt may be asymmetric by virtue of having a cam surface.

The operating member may be rotatable to retract the latch bolt.

An embodiment of the invention will now be described by way of examples reference to the accompanying drawings wherein: Figure 1 is a fragmentary perspective view of part of a mortice latch embodying the invention, Figure 2 is a front view of Figure 1, and Figure 3 is a section on the line 3-3 of Figure 2.

Referring to the drawing, a mortice lock comprises a conventional case 10 having inner and outer fore-end plates 12, 13 each provided with an apertures 14 for a latch bolt 16. The apertures 14 and latch bolt 16 are of a mutual size so that the latch bolt at its largest dimension portion adjacent to its inner end is a sliding fit in the apertures 14 and, in an at rest position of the latch bolt with the latch bolt in an extended position has said inner end portion 18 of the latch bolt disposed within the apertures 14. The latch bolt 16 is asymmetric by virtue of being provided with a curved surface part 18a which acts as a cam surface but could be of any other configuration if desired.

The latch bolt 16 is fixed to a latch shaft 20 by, in the present example, a roll pin 22 received in a bore in the latch bolt and extending through a transverse bore, not shown, in the latch shaft 20. The latch shaft 20 is cylindrical and is received within a cylindrical bore in the latch bolt 16.

The latch bolt 16 is carried on a latch lath 24 which is provided with an upstanding lug 26 made, in the present example, by bending an upturned part from a pressing from which the latch lath 24 is made. The lug 26 has an aperture 28 in which the lug shaft 20 is slidably and rotatably received. A coil compression spring 30 is engaged between an inwardly facing surface 32 of the lug 26 and an abutment 34 provided adjacent the inner end of the latch shaft 20 by a circlip 36 received in a groove, not shown, formed in the latch shaft 20 in conventional manner.

The latch lath 24 is resiliently biased to an extended position in which the latch bolt 16 projects outwardly of the fore-end 12, by a coil compression spring 38 mounted at one end on a reduced diameter part 40 of a mounting peg 42 fixed to the lug 26 of the latch lath and abutting, at its other end, an upstanding lug 44 pressed out of the lock case 10.

The latch lath and hence the latch bolt 16 carried thereby can be moved from the extended position to a retracted position in which the latch lath does not project outwardly of the fore-end 12 or does not project substantially outwardly therefrom by virtue of a drive lever 46 rotatably mounted relative to the lock case and rotatable by an operating member which may be provided with a handle, not shown. The lever 46 engages an upturned lug 48 of the latch lath.

Although the operating member is rotatably mounted to retract the latch bolt, the operating member may be moveable in any desired manner to retract the latch bolt.

A slider 50 is slidably mounted relative to the lock case and has a recess 52 in which there is slidably received a block 54 which is fixed to the lock case. The slider 50 has a first lug 56 at its front end which is engaged by a coil compression spring 58 so as to resiliently bias a second lug 60 against the drive lever 46 and against the bias of which the drive lever can be moved to permit of said movement of the latch lath from the extended position to a retracted position.

Where it is desired to change the hand of the lock, the latch bolt 16 is grasped manually and pulled in a direction outwardly of the lock case to compress the coil compression spring 36 and free the inner end part 18 of the latch lath from the apertures 14 thereby enabling the latch bolt 16 to be rotated through 1800, from the position shown in full line in the Figure 5. The end portion 18 is then allowed to re-enter the apertures 14 under the bias of the coil compression spring 34.

In the present example, the latch bolt 16 has projecting wings 62 and each aperture 14 is correspondingly configured at both sides of the aperture so that the wings 62 can be received in corresponding slots 63 in either of the positions shown in the figure.

The above-described co-operating wings and slots 62, 63 have a relatively close clearance and serve as a guide means to maintain the latch on a predetermined track and to avoid play and, in particular, to prevent the latch moving transversely to its direction of retraction as curved surface part 18a of the latch moves into the apertures 14.

Alternatively, if desired, the wings 62 may be provided on the fore-ends 12, 13 and an appropriate pair of projecting wings 62 being received in grooves provided on the latch instead of the wings 62.

Further alternatively, the guide means may be provided in any other desired manner, for example, by providing projecting ribs of desired configuration on the latch or fore-ends for reception in an appropriate groove or grooves on the fore-end or latch respectively. The number of pairs of ribs may be varied as desired as may their position transversely of the latch.

The above-referred to rib configuration may amount to wings 62 and corresponding slots 63 provided on the latch bolt and fore-ends 12, 13 respectively or the reverse arrangement and may be positioned at the mid point of the latch so that only two opposed wings or ribs and recesses are required irrespective of the orientation of the latch bolt within the fore-ends.

The above described arrangement enables the lock to be handed without the need to disassemble the lock thereby considerably facilitating a handing operation.

The features disclosed in the foregoing description, or the following claims, 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 (12)

1. A mortice latch of the kind described wherein the latch bolt comprises means enabling it to be handed.

2. A mortice latch according to Claim 1 wherein the connection between the latch bolt and the latch lath comprises a shaft fixed to one of the said elements and which is slidably and rotatably received in an aperture in the other opposite element, there being resilient biasing means to bias the latch bolt relative to the latch lath in a direction inwardly of the case so as normally to dispose a portion of the latch bolt within the aperture in the fore-end when the latch lath is in its extended position and whereby the latch bolt may be manually displaced outwardly of the aperture in the fore-end and then rotated to change the hand followed by release of the latch bolt so as to be biased inwardly of the case so as to again position a portion of the latch bolt within said aperture.

3. A mortice latch according to Claim 2 wherein the latch shaft is fixed to the latch bolt and slidably received within an aperture of the latch lath.

4. A mortice latch according to Claim 3 wherein the latch lath is provided with an upstanding lug extending perpendicular to the direction of movement of the latch lath in which said aperture is provided.

5. A mortice latch according to Claim 4 wherein a coil compression spring is disposed between a side face of the lug and an abutment provided on the latch shaft.

6. A mortice latch according to any one of the preceding Claims wherein the latch bolt comprises one or more guides which engage a desired one of a pair of guide means.

7. A mortice latch according to Claim 6 wherein the guide means are provided in the fore-end.

8. A mortice lock according to Claim 6 or Claim 7 wherein the guides comprise ribs disposed lengthwise of the latch bolt and the guide means comprise grooves into which the ribs are received.

9. A mortice latch according to any one of the preceding Claims wherein the latch bolt is asymmetric by virtue of having a cam surface.

10. A mortice latch according to any one of the preceding Claims wherein the operating member is rotatable to retract the latch bolt.

11. A mortice latch substantially as hereinbefore described with reference to and as shown in the accompanying drawings.

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