GB2431690A

GB2431690A - A door latch with a rotatable latch bolt

Info

Publication number: GB2431690A
Application number: GB0521995A
Authority: GB
Inventors: Mark Naylor
Original assignee: Architectural Products & Compo
Current assignee: Architectural Products & Compo
Priority date: 2005-10-28
Filing date: 2005-10-28
Publication date: 2007-05-02
Also published as: WO2007049021A1; GB0521995D0

Abstract

A latch bolt comprising a casing (10) having a fore end (11) and containing a latch bolt (12) mounted on a sliding plate (15) within the casing, the latch bolt (12) being retractable against a spring (18) by means of a handle follower (13) rotated by a spindle (14). An eccentric cam (32) which may be rotated on a slotted spindle (33) is adapted to move the latch bolt (12) on a spindle (27) outwardly beyond the fore end (11) and relative to the plate (15) so that it may be rotated about 180{ to reverse the latching direction of the latch bolt. The cam (32) may then be rotated again to return the latch bolt to its position within the fore end (11). Thus, the direction of the latch may be reversed without opening the casing (10) by inserting a screwdriver in the slotted spindle (33) which is exposed at the surface of the casing (10) through an aperture therein.

Description

I

A DOOR LATCH WITH A ROTATABLE LATCH BOLT

This invention concerns a door latch of the kind comprising a casing adapted to be installed within an edge region of a door and enclosing a latch bolt which protrudes from the door and in use locates within a latch plate mounted on a door frame, the latch bolt having one angled face to provide a latching action.

Conventionally, it has been necessary for such latches to be manufactured and installed according to the direction in which the door closes. This is because such latches also have a dead bolt or mortise lock incorporated within the casing and operated by a key where the bolt is usually located at a level below the latch bolt.

In some conventional door latches of this kind it has been possible to reverse the direction of the latch by opening the casing and dismantling the relevant parts in order to place the latch in the casing with the angled face located for a left handed or right handed door.

Certain mechanisms have been proposed to enable the latch bolt to be rotated through 180 by means accessible from outside of the casing. Such means have included separate parts which must be introduced through an aperture in the casing moving the latch bolt forwardly out of the casing to a position in which it is free of the fore end of the casing and may be rotated as required.

An object of the present invention is to provide a reversible door latch of this kind having means immediately accessible from outside of the casing without the need for the manufacturer to supply a separate key or other part to reverse the latch.

According to the present invention there is provided a door latch comprising a casing having a fore end, a latch bolt housed within the casing and movable between a latching position in which it extends outwardly from the casing through an aperture in the fore end and an unlatching position in which it is withdrawn within the casing against resilient means therein, a plate slidable within the casing and carrying the latch bolt, and a follower movable within the casing to engage the plate and in turn to move the latch bolt from its latching position to its unlatching position; characterised in that the latch bolt is movable relative to the plate by rotary means accessible from outside of the casing which when rotated moves the latch bolt relative to the plate to cause the latch bolt to extend outwardly of the fore end beyond its latching position whereupon it may be rotated relative to the casing to reverse its latching direction.

The latch bolt may be rotatably mounted with respect to the plate.

The rotary means may comprise a cam eccentrically mounted on a spindle the cam surface abutting a movable pin upon which the latch bolt is mounted.

The spindle may have a part exposed through an aperture in the casing said part having a formation engageable by a tool.

The formation may be a slot engageable by a screwdriver.

The plate may have an abutment engageable by a handle follower to cause withdrawal of the plate and of the latch bolt.

A spring may urge the handle follower into a position in which the latch bolt is extended into its latching position.

The formation may be substantially flush with an outer surface of the casing.

An embodiment of the invention will now be described, by way of example only, with reference to the accompanying drawings in which: Fig. I illustrates a typical door latch with deadbolt and incorporating a latch bolt reversal mechanism in accordance with the invention; Fig. 2 is an overhead view of the door latch; Fig. 3 is a view similar to Fig. I showing the latch with the latch bolt reversal mechanism actuated to allow reversal of the latch; and Fig. 4 is an exploded view of the latch bolt reversal mechanism to an enlarged scale.

Referring now to the drawings a door latch comprises a casing 10 having a fore end 11 a latch bolt 12 housed within the casing and movable between a latching position wherein it extends outwardly as shown in Fig. I from the casing 10 through an aperture in the fore end 11, and an unlatching position in which it is withdrawn within the casing by means of a handle follower 13 rotatable about a spindle 14 extending through the casing and attached to the door handle. In a typical assembly of this kind, the latch bolt 12 is mounted on a plate 15 slidable linearly on a peg 16 in the casing so as to carry the latch bolt outwardly and inwardly as required, the plate 15 being actuated by the follower 13 acting against an abutment 17 at the rear end of the plate 15. A leaf spring 18 mounted in the casing on a peg 19 acts against an inner fore end 20 on the plate 15 to urge the latch bolt into its latching position as illustrated in Fig. 1.

The cam follower 13 has a lug 21 which acts on a pin 22 against a coil spring 23 and mounted on a fixed casing member 24. Clockwise rotational movement of the cam follower 13 as seen in Fig. 1 is limited by a further lug 25 acting, upon rotation, against a peg 26 fixed within the casing.

In accordance with the present invention, the latch bolt 12 is mounted on a pin 27 slidable within an inverted u-shaped member 28 fixed to the plate 15. A coil spring 29 acts between the inner fore end 20 and a collar 30 fixed to the pin 27. Thus, the latch bolt 12 and the pin 27 can extend forwardly of the inner fore end 20 against the action of spring 29 and relative to plate 15. Mounted within the member 28 eccentrically on a spindle 31 is a cam 32. At one end of the spindle 31 is a crosshead formation 33 which is accessible through an aperture in the casing wall and lies substantially flush with the latter.

Referring now to Fig. 3 it can be seen that by inserting the tip of a screwdriver in the crosshead formation 33 of spindle 31, the spindle and thus the cam 32 may be rotated by 180 to push pin 27 and latch bolt 12 outwardly through the fore end 11 to an extent beyond the latching position of the bolt 12. Once free of the fore end 11, the bolt 12 may be rotated upon its pin 27 through 180 and then the cam 32 may be rotated back to its position as shown in Fig. I to reintroduce the latch bolt into the fore end 11 so that the latching direction of the angled latch bolt 12 has thus been reversed.

By this method, a left handed latch bolt may be converted to a right handed latch bolt, and visa versa, without opening the casing 10 and without the need to introduce a special tool or otherwise into the casing through an aperture therein.

It is not intended to limit the invention to the details described herein. For example, the cam 32 may be replaced by any other member capable, upon rotation of spindle 31, of advancing the pin 27 and latch bolt 12 outwardly from the casing and for allowing it to return into the casing having been reversed in direction. If necessary, the spindle 31 may have a formation on opposed ends so as to be exposed and accessible at both sides of the casing.

Claims

CLAIMS

1. A door latch comprising a casing having a fore end, a latch bolt housed within the casing and movable between a latching position in which it extends outwardly from the casing through an aperture in the fore end and an unlatching position in which it is withdrawn within the casing against resilient means therein, a plate slidable within the casing and carrying a latch bolt, and a follower movable within the casing to engage the plate and in turn to move the latch bolt from its latching position to its unlatching position; characterised in that the latch bolt is movable relative to the plate by rotary means accessible from outside of the casing which when rotated moves the latch bolt relative to the plate to cause the latch bolt to extend outwardly of the fore end beyond its latching position whereupon it may be rotated relative to the casing to reverse its latching direction.

2. A door latch according to claim 1 wherein the latch bolt is rotatably mounted with respect to the plate.

3. A door latch according to claim I or claim 2 wherein the resilient means comprises a spring acting on the plate to urge the latch bolt into its latching position.

4. A door latch according to any preceding claim wherein the latch bolt is resiliently mounted on the plate with a spring urging the latch bolt against an inner fore end on the plate.

5. A door latch according to any preceding claim wherein the rotary means comprises a cam eccentrically mounted on a spindle, the cam surface abutting a movable pin upon which the latch bolt is mounted.

6. A door latch according to claim 5 wherein the spindle has a part exposed through an aperture in the casing, said part having a formation engageable by a tool.

7. A door latch according to claim 6 wherein the formation is a slot engageable by a screwdriver.

8. A door latch according to claim 6 or claim 7 wherein the formation is substantially flush with an outer surface of the casing.

9. A door latch according to any preceding claim wherein the plate has an abutment engageable by a handle follower to cause withdrawal of the plate and of the latch bolt.

10. A door latch according to claim 9 including a spring which urges the handle follower into a position in which the latch bolt is extended into its latching position.