GB2152576A - Strike assembly - Google Patents

Abstract

A strike assembly for mounting in a door jamb includes an exposed keeper (14) mounted in a housing (12) for rotational movement between a bolt retention position and a bolt release position. Elongate latch means (18) in the form of a pin supported in the housing is longitudinally movable to engage the keeper (14) and so prevent it from moving from its bolt retention position. Means (52) (eg a solenoid) is also provided to drive the latch means (18) to and/or from its keeper engaging condition. <IMAGE>

Description

SPECIFICATION Strike assembly This invention relates generally to security locks and is concerned in particular with the strike components of such locks.

It is known to provide a security lock strike assembly having a rotatably mounted keeper and an electrical latch device engageable with the keeper to hold it ina a bolt retention position. On de-activation of the latch device, the keeper is rotatable against a coil spring so that the doorway may be opened by simply pushing on the door. In one arrangement, disclosed in Australian Patent Specification 426,474, the latch device comprises an elongate metal arm housed in the wall cavity and held in its keeper locking position by an energized solenoid. In another known commercial construction, the latch device is rendered more compact by forming it as a pivotable catch held in locking engagement with a stop on the keeper by means of a solenoidresponsive finger housed under the keeper and latch.

It will be appreciated that security strike assemblies of the kind discussed can be readily released, by withdrawal of electrical power, in the event of a fire or other emergency and yet be otherwise positively locked against unauthorized passage in either direction through the door. Moreover, by virtue of the spring loading of the keeper, there is no partial and unnecessary opening of the door on release of the latch device. It has been realised, in accordace with the invention, that significant advantages can be obtained by providng a novel strike assembly with latchable rotatable keeper.

The invention accordingly provides a strike assembly comprising: a housing adapted for mounting in a door jamb; an exposed keeper mounted in the housing for rotational movement between a bolt retention position and a bolt release position; elongate latch means supported in said housing and longitudinally movable to an operative condition in which it engages the keeper and so prevents said rotational måSSe- ment of the keeper from its bolt retention position; and means to drive the latch means to and/or from said operative condition.

Preferably, the movable elongate latch means engageable with the bolt is a pin, rod or the like adapted, in its bolt retention position, to project into a hole in the keeper.

The latch means may be so arranged that it tends to fall from engagement with the keeper under gravity unless held in its operative condition. A helical spring may be provided to augment the gravity bias on the latch means.

The aforesaid drive means is advantageously electrically operable to drive the latch means, directly or indirectly, into locking engagement with the keeper and to retain it in such locking engagement. Such electrically operable drive means is preferably a solenoid: the solenoid, pin and hole may be substantially co-axial.

The housing may define a cavity for the keeper, the latch means extending through an aperture in a wall bounding the cavity.

The strike assembly may further include catch means for locating the keeper in its bolt retention position, even on release of the latch means, until a predetermined rotational force is applied to the keeper for moving it to its bolt release position. Such catch means is conveniently a spring-loaded element in the keeper and may alternatively or additionally act conversely by locating the keeper in its bolt release position unless a predetermined rotational force is applied for returning the keeper to its bolt retention position.

The keeper may be configured to receive a rectangular lockbolt. To prevent geometric locking of the bolt in the keeper as it rotates while maintaining a firm engagement at the bolt retention position, the keeper may be formed with a convex internal side face.

The invention will be further described, by way of example only, with reference to the accompanying drawings, in which: Figure 1 is a perspective view of a strike assembly in accordance with the invention, shown with its keeper held in the bolt retention position; Figure 2 is a side elevation of the assembly with the near portion of the housing omitted and the latch de-activated; Figure 3 is a cross-section on the line 3-3 in Fig. 2; and Figure 4 is a view similar to Fig 3 but showing the position of the keeper after it is released and the door pushed open.

The illustrated strike assembly 10 includes a metal box housing 1 2 at one side (the inside relative to the room being protected), a rotatably mounted exposed keeper 1 4 in register with a front bolt receiving opening 1 6 in housing 12, and latch means indicated generaily at 1 8 (Figs 2 to 4).

Housing 1 2 is intended to be mounted in a suitably formed recess in the jamb of a doorway and held in place by means of screws fitted through apertures 22 in a front facing plate 24 forming part of the housing. Bolt opening 1 6 extends wholly across plate 24 and partially across a side plate 25 which would normally be on the outside relative to the room being protected.

Keeper 14 is a unitary metal casting of substantial thickness. It is somewhat elongate, defining (Fig. 3) a forward channel 28 and a pair of rear tapered faces 30, 31 about a bore 32 by which it is rotatably mounted to a pin 34. When the assembly is in situ, pin 34 and channel 28 extend vertically and the mouth of the channel co-incides vertically with opening 1 6. Pin 34 journalled in a pair of internal horizontal partitions 36, 37 which form integral portions of housing 1 2 at the bottom and top of opening 16, and define a cavity 1 9 for the keeper.

Keeper 14 is configured to receive a rectangular deadlock bolt (shown at 8 in broken lines in Figs. 3 and 4) in that channel 28 has a planar floor 47 and side faces 38 39 which are respectively planar and convex. Planar face 38 is on the outside of the channel relative to the room being protected and this comprises a catch face for the bolt. Convex face 39 prevents geometric locking of the bolt in the keeper, as will become more apparent hereinafter.

Latch means 1 8 comprises an elongate element in the form of a pin or plunger 40 (Fig.

2) which is vertically slidably supported in an aperture 42 in housing partition 36 and in a boss 37 protruding from its bottom surface.

Plunger 40 registers at one end with a blind hole 44 in the underside of keeper 14 behind hinge pin, and is fitted at the other end with a head flange 46. A lelical compression spring 48 mounted between partition 36 and flange 46 biases the plunger downwardly out of hole 44 into abutment with the top of an inverted V cradle 50 that is fixed inside housing 1 2 and carries a solenoid 52. The solenoid surrounds a ferromagnetic core rod 54: solenoid 52, rod 54, plunger 40 and hole 44 are coaxial. On energization of the solenoid, by application of an emf on conductors 53, rod 54 is magnetically raised through an aperture in the top of cradle 50 to abut and lift plunger 40 firmly into hole 44 against spring 48. The plunger thereby engages the keeper and so prevents rotational movement of the keeper from its bolt retention position, shown in Figs.

1 to 3.

If the solenoid is de-energized, by switching off the current supply, core rod 54 and plunger 40 fall under gravity, aided by spring 48, to withdraw the plunger from hole 44 and so permit the keeper to be rotated (Fig. 4) and therefore the door to be pushed open. The internal convex face 39 of the keeper allows the bolt to clear channel 28 as the keeper rotates, thus preventing geometic locking of the parts.

A spring-loaded ball 56 in a second blind hole 45 in the top face of the keeper will locate in an aperture 43 in partition 37 to locate the keeper in its bolt retention position, even on release of latch 1 8, until a predeter mined force is applied to the keeper for mov ing it to its bolt release position. Alternatively or additionally ball 56 might act conversely by locating the keeper in a bolt release position unless a predetermined rotational force is ap plied for returning the keeper to its bolt retention position. This prevents wobble of the keeper in either position.

It will be appreciated that the inventive strike assembly is an especially compact and readily set arrangement for providing a releasable keeper for a deadbolt or like mechanism.

Under normal circumstances, the door cannot be pushed open, but in the event of an emergency such as a fire, the door lock can be wholly released but not necessarily opened by simple withdrawal of the electric current (which withdrawal is often caused by fire or is necessary in the event of fire). The door can then be pushed open without any need to operate a handle or release a further lock.

The whole latch assembly is conveniently and neatly confined within a strike housing of box configuration in the jamb and does not extend further into the wall cavity, as with the arrangement of patent 426,474.

It will be appreciated that the pin and solenoid may be inversely operable so that the pin is normally biased into locking engagement with the keeper and the solenoid is activated to release such engagement.

Claims (11)

1. A strike assembly comprising: a housing adapted for mounting in a door jamb; an exposed keeper mounted in the housing for rotational movement between a bolt retention position and a bolt release position; elongate latch means supported in said housing and longitudinally movable to an operative condition in which it engages the keeper and so prevents said rotational movement of the keeper from its bolt retention position; and means to drive the latch means to and/or from said operative condition.

2. A strike assembly according to claim 1 wherein the movable elongate latch means engagable with the bolt is adapted, in its bolt retention position, to project into a hole in the keeper.

3. A strike assembly according to claim 1 or 2 wherein said latch means comprises a pin, rod or like element.

4. A strike assembly according to claim 1, 2 or 3 wherein the latch means is so arranged that it tends to fall from engagement with the keeper under gravity unless held in its operative condition.

5. A strike assembly according to any preceding claim further including spring means to bias said latch means out of its operative condition.

6. A strike assembly according to any preceding claim wherein said drive means is electrically operable to drive the latch means, directly or indirectly, to said operative condition and to retain it in such condition.

7. A strike assembly according to claim 6 wherein said electrically operable drive means is a solenoid which is co-axial with a pin comprising the latch means.

8. A strike assembly according to any preceding claim wherein the housing defines a cavity for the keeper, the latch means extending through an aperture in a wall bounding the cavity.

9. A strike assembly according to any preceding claim further including catch means for locating the keeper in its bolt retention position, even on release of the latch means, until a predetermined rotational force is applied to the keeper for moving it to its bolt release position.

10. A strike assembly according to any preceding claim wherein, to prevent geometric locking of the bolt in the keeper as it rotates while maintaining a firm engagement at the bolt retention position, the keeper is formed with a convex internal side face.

11. A strike assembly substantially as hereinbefore described with reference to the accompanying drawings.