GB2111113A - Striking plate for latches - Google Patents

Abstract

A latch-bolt (38) can be directly released from its keeper by tilting an armature plate (28) to remove its detent on a pivotable locking plate (12). The armature plate (28) can be tilted by means of an electromagnet formed by coils on a U-shaped rod (35) whereby to remove the abutting engagement of the armature (28) with the locking plate (12) and thereby permit the locking plate to be pivotted to allow the latch member (38) to pass. The locking plate (12), armature (28) and a base plate (10) on which the for locking plate and armature are mounted, are preferably all made from sheet metal. <IMAGE>

Description

SPECIFICATION Electric release The present invention is concerned with an electric release of the type wherein a bolt or latch is held captive until released by a mechanism which is operated electrically.

Such release devices are used, for example, in door locks where access to the door is only to be permitted upon the provision of a predetermined electrical control signal, provided for example, by a computer. Known devices of this type are relatively complex and correspondingly expensive. They normally utilise an electromagnetically operable plunger which is axially displaceable to selectively engage a bolt or latch of the door to withhold or enable access to the door. Other releases employ hinged lever plates moved by electro-magnets as in relays which block movements of other members and require substantial mechanical lever systems to amplify the strength.

It is an object of the present invention to provide an electric release which is of simpler construction yet operates at least as realiably as the known devices referred to above.

In accordance with the present invention, an electric release for selectively restraining and releasing a latch member comprises a pivotable locking plate which is normally prevented from rotating by abutting engagement with an elongate edge of a plate-like armature, the armature being displaceable by means of an electromagnet whereby to selectively remove said abutting engagement with the locking plate and thereby permit pivotting of the locking plate to allow the passage of the latch member therepast.

Preferably, the armature comprises a rectangular metal plate, one side edge of which engages the locking plate in the locked position. Advantageously, the whole of said side edge engages the locking plate.

Preferably, the armature plate is tiltably mounted on a base plate on which the locking plate is also pivotally mounted.

Conveniently, the locking plate, the armature plate and the base plate are all made from sheet metal.

The locking plate is preferably biassed towards the locked position by one or more springs. The same spring or springs can be used to biass the armature to the locked position when the electromagnet is de-energised. For this purpose, the or each said spring can be carried by a pivot for the locking plate, one end of the or each spring engaging the locking plate and the other end of the or each spring engaging in a respective aperture in the armature plate.

The invention is described further hereinafter, by way of example only, with reference to the accompanying drawings, in which: Figure 1 is a partially sectioned side view of one embodiment of an electrically operated release in accordance with the present invention; and Figure 2 is a front view of the device of Fig.

1, with its moulded cover removed.

The illustrated device comprises a bracket 10 of sheet metal having a base portion 1 Oa, upstanding sides portions 1 0b and a depending flange portion 10c. A sheet metal locking plate 1 2 is pivotally mounted on the bracket 10 by means of a pivot 14 which extends between the two side portions 1 0b and passes through respective apertures 1 6 in depending side portions 1 8 of the plate 1 2.

One end of the locking plate 1 2 is bent over so as to present a rounded operating edge 20 as shown in Fig. 1. The locking plate 1 2 biassed towards the position it occupies in the drawings by means of a pair of coil springs 22 whose one end portions 24 engage the underside of the plate 1 2 and whose other end portions 26 react effectively against the base portion 1 0a of the bracket 1 0.

Disposed so as to normally lie between the base portion 1 0a of the bracket 10 and the underside of the locking plate 1 2 is a sheet metal armature plate 28. In the normal stable state of the device the plate 28 thus lies perpendicular to both the base portion 1 0a and the locking plate 1 2. The armature plate 28 is of generally rectangular configuration and, when in said normal condition, engages the rear edge of the underside of the locking plate 1 2 along the whole of the iength of the armature plate.

The end portions 26 of the springs 22 engage through respective apertures 30 in the armature plate 28 so as to biass the plate 28 into its normal (illustrated) position as described further below. The bottom end of the plate 28, as viewed in Fig. 1, is loosely guided on the base portion 1 Oa of the bracket 10 by means of two pairs of opposed stops 32 partially pressed out of the base portion 10a which enable the armature plate to tilt about its lower edge relative to the base portion 1 Oa.

The parts as described thus far are snapfitted into a plastics moulding 34 into which has been pressed an electromagnet comprising a U-shaped steel rod 35 having a coil or coils (not shown) surrounding it whose terminals are shown at 36, 38. The steel rod is disposed such that upon energisation of the coil(s) the armature plate 28 is tilted anticlockwise as viewed in Fig. 1 so as to become disengaged from the locking plate 1 2. The springs 22 normally maintain the locking plate in its illustrated (full line) position.However, in this condition, it is capable of being pivotted, against the bias of the springs 22, to the position shown in chain lines in Fig. 1, the limit of this pivotting movement being determined by a pair of stops 36 partially pressed out of the upright side portions 1 0b of the bracket 1 0. The moulding 34 is recessed at 34a to permit this pivotal movement of the latch plate.

In use, the bracket 10 is mounted so as to cooperate with a spring loaded latch 38, indicated diagrammatically in Fig. 1. For example, the bracket 10 could be rigidly attached to a fixed door frame and the latch 38 could be carried by the door, or vice versa. As long as the armature plate remains in its illustrated position, the locking plate 1 2 cannot be pivotted and the latch 38 is held in piace to maintain the door locked in its closed position. However, when the coil is energised to displace the armature plate from its engagement with the locking plate 12, the door can be opened since the latch 38 can pivot the locking plate 1 2 out of its path to the position shown in chain lines. When the latch 38 has cleared the locking plate 12, the latter plate is returned immediately to its initial position by the springs 22. Furthermore, as soon as the coil is de-energised, the spring portions 26 which engage the sides of the apertures 30 are effective to return the armature plate to its initial, illustrated position where it again engages the path of the locking plate to prevent further pivotal movement.

The door can, however, be closed again by virture of the spring action of the springloaded latch 38.

The springs 22 which keep the locking plate in its normal (full line) position are arranged to act quite strongly, and serve to protect the armature plate from side load which could inhibit its movement and prevent electrical release.

Claims (11)

1. An electric release for selectively restraining and releasing a latch member, comprising a pivotable locking plate which is normally prevented from rotating by abutting engagement with an elongate edge of a platelike armature, the armature being displaceable by means of an electromagnet whereby seiec- tively to remove said abutting enagagement with the locking plate and thereby permit pivotting of the locking plate to allow the passage of the latch member therepast.

2. An electric release as claimed in claim 1, wherein the armature comprises a rectangular metal plate, one side edge of which engages the locking plate in the locked position.

3. An electric release as claimed in claim 2, wherein the whole of said side edge engages the locking plate in the locked position.

4. An electric release as claimed in claim 1, 2 or 3 wherein the armature plate is tiltably mounted on a base plate on which the locking plate is also pivotally mounted.

5. An electric release as claimed in claim 4 wherein the locking plate, the armature plate and the base plate are all made from sheet metal.

6. An electric release as claimed in claim 5, wherein the end of the armature plate engaging the base plate is guided loosely to enable it to tilt on the base plate by means of opposed stops formed by partially pressing out the base plate.

7. An electric release as claimed in claim 5 or 6, wherein the assembly comprising the locking plate, armature and the base plate is snap-fitted into a moulded plastic housing containing the electromagnet.

8. An electric release as claimed in any of claims 1 to 7, wherein the locking plate is biassed towards the locked position by one or more springs.

9. An electric release as claimed in claim 8, wherein said one or more springs are also adapted to bias the armature to the locked position when the electromagnet is de-energised.

10. An electric release as claimed in claim 9, wherein the or each said spring is carried by a pivot for the locking plate, one end of the or each spring engaging the locking plate and the other end of the or each spring engaging in a respective aperture in the armature plate.

11. An electric release constructed and adapted to operate substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.