GB2241018A - Lock or latch operating mechanisms - Google Patents

Abstract

A lock is provided with a mechanism comprising a security-coded keying device (30) for withdrawing a latching member or bolt (not shown). By use of the keying device. a normally disengaged coupling means (10) in the mechanism can be acted upon to interconnect the latching member with a handle turning a slotted spigot 8 to allow the latch to be withdrawn. After withdrawal, the coupling of the latching member with the operating member is released again by means of a spring biassed slider 40 returning to its rest position. <IMAGE>

Description

LOCK OR LATCH OPERATING MECHANISMS This invention relates to locks or latches, and in particular to operating mechanisms for locks or latches having a displaceable bolt or other locking member.

Latches are known in which a bolt, connected directly to a handle or a solenoid, is withdrawn in conjunction with operation of a digital security-coded device, when a user enters the correct code. Such devices may, for example, comprise a series of buttons which the user must press in a predetermined sequence. The available range of latches operated by security-coded devices is relatively limited, however, so they are not employed to the extent that their advantages might merit.

According to the present invention, there is provided an operating mechanism for a lock or latch having a displaceable bolt or other latching member, the mechanism comprising an operating member for releasing the latching member and disengageable coupling means for interconnection between the operating and latching members, means for connecting the operating and latching members through said coupling means being operable by means of a keying device, the operating member and the latching member being normally disconnected from each other.

The keying device can conveniently comprise any known form of security-coded device. The same form of device may be arranged to be employed for different types of lock or latch so as to make it possible to provide security-coded operation for a wide range of locks and latches. By the use of the invention it is also possible to modify an already-installed lock or latch to operation by a security-coded mechanism.

A variety of keying devices may be utilised to obtain the engagement of the coupling means. It will generally be appropriate to have devices of the kind which requires the user to enter a correct digital code, whether mechanically or electrically, but the invention is not so limited.

Preferably, means are provided to disengage said coupling means upon operation of the latching member by the operating member whereby the keying device must be employed for each release of the latching member.

One example of an operating mechanism according to the present invention will be described with reference to the accompanying drawings, in which: Fig. 1 is an exploded oblique view of the mechanism from the rear, and Fig. 2 is an oblique view of the front of the mechanism.

The illustrated construction is intended to be employed with a door latch, for example, although the latch itself is not shown. A mounting plate 2 (shown with a decorative cover 2a in Fig. 2) to be secured to the outer face of the door has a door handle 4 mounted at a fixed position on it to be pivotable between stops (not shown) against the action of a spring 5 that urges it to its illustrated horizontal position. The handle boss 6 projects from the back of the plate 2 where it is provided with a radial slot 8 in its rear face. A coupling 10 for connecting the handle to the latch is mounted on a lever arm 12 which is rotationally supported at one end on a pillar 14 fixed to the mounting plate 2.

The coupling includes a first member 16 held in the lever in a rotary bearing 18 defining a pivot axis parallel to the handle rotary axis. The coupling also has a second member 20 connected to the first by a pivot 22 on an axis transverse to the axis of the bearing 18. The first member 16 has at its forward end a first tongue 24 that can slide radially into and out of the slot 8. As the tongue enters the slot and comes approximately coaxial with the bearing 18, the coupling is rotatably engaged by the handle 4. The second member 20 of the coupling has a second tongue 26 at its rear end permanently engaged in a slot (not shown) in a rotary member of the door latch in such a manner as to turn with that member but to be otherwise free to move relative to it. The tongues 24,26 both extend diametrically of the coupling rotary axis and non-perpendicular to the axis of the pivot 22.The pivot 22 permits engagement between the coupling member 20 and the latch member to be maintained as the coupling moves with the pivoting lever arm 12.

The mechanism is normally in a rest state in which the slot 8 is aligned with the first tongue 24 but the lever arm 12 is in its upper position so that the tongue is spaced from the slot and the coupling 10 is disengaged from the handle 4. When the lever arm is pivoted to a lower position the first tongue 24 is engaged with the slot 8 and turning the handle will release or withdraw the latch. The mechanism is brought to the latch-releasing state by use of a digitally coded lock device 30, which may be of generally conventional form.

In such locks, typically, the entry of a given code through digital buttons 32 or the like allows a release member such as the turn-button 34 to be operated.

In the present example, a cam 36 at the rear of the mounting plate 2 is fixed to the same shaft 34 as the turnbutton to rotate therewith. The cam bears against a bar 40 which is constrained to slide linearly on the mounting plate 2 by guides formed on the one side by an edge of a fixed carrier plate 42 and on the other by pegs 44. The bar 40 is urged upwards, to be kept in contact with the cam 36, by a spring 46 connected between an anchor 48 on the mounting plate and a yoke 50 of the bar. The pegs 44 also define the limits of movement of the bar 40 by engagement with a side projection 52 on it.

The end of the lever arm 12 remote from the pillar 14 is located between the horns 54 of the yoke. As the bar 40 is moved downwards by the cam 36, therefore, the lever moves with it and slides the first tongue 24 into the slot 8 in the handle boss.

A blocking member 60 is held on the carrier plate 42 by guides 62 to be slidable transversely to the bar 40.

In the disengaged state of the mechanism, the blocking member straddles a detent 64 fixed to the bar, the detent being located in a recess 66 of the member 60. A spring 68 engages in aperture 70 in the blocking member to urge the member away from the bar 40 so that end projection 72 of the member is held in contact with the detent 64. As the bar 40 is lowered by rotating the cam 36 through the turnbutton 34, the detent 64 moves past the blocking member 60.

The member 60 is then displaced by the spring 68 to bring the projection 72 into the path of the detent 64, preventing its return and so holding the bar 40 in its lowered position. The engagement of the first tongue 24 in the handle slot 8 is thereby maintained when the turnbutton is released.

Rotation of the handle can now release the latch.

With its rotation, a pin 80 projecting from the boss 6 moves clockwise as seen in Fig. 1 to bear against a spur 82 on the blocking member 60 as the pin moves substantially horizontally across the lowest part of its arc. The blocking member 60 is thereby displaced in its guides 62, against the action of the spring 68, to bring the recess 66 once more into register with the detent 64. Under the action of the spring 46, the bar 40 is now returned to its upper position, so that the coupling 10 is disengaged from the handle 4 as soon as the latch has been released. The digital coding device 30 must be operated again if the latch is to be released again.

It will be noted that illustrated mechanism is substantially independent of the lock or latch to be operated. It can thus be employed with a variety of locks and latches, and may even be retrofitted to an existing installation. The element making operative connection with the lock or latch, in the illustrated example the first tongue 24, can of course be given different forms as required and can even be arranged to accommodate operating movements other than the rotary movement described.

In most applications, a lock or latch will require to be fitted with a single operating mechanism according to the invention. It is possible, however to have an additional mechanism, eg. where security-coded operation is required to access in either direction past a door.

Claims (10)

1. An operating mechanism for a lock or latch having a displaceable bolt or other latching member, the mechanism comprising an operating member for releasing the latching member and disengageable coupling means for interconnection between the operating and latching members, means for connecting the operating and latching members through said coupling means being operable by means of a keying device, the operating member and the latching member being normally disconnected from each other.

2. A mechanism according to claim 1 wherein the keying device is a security-coded device.

3. A mechanism according to claim 1 or claim 2 wherein the coupling means are arranged to be continuously engaged with the latching member.

4. A mechanism according to any one of the preceding claims wherein the coupling means is rotatable by the operating member and comprises an engagement element that is displaceable transversely-to the axis of rotation for engagement and disengagement with said member.

5. A mechanism according to claim 4 wherein the coupling means comprises a further engagement element that is displaceable transversely to said axis of rotation with respect to the latching member.

6. A mechanism according to claim 4 and claim 5 wherein said elements are relatively displaceable about a pivot axis that extends non-perpendicularly to said direction of transverse displacement of the engagement elements.

7. A mechanism according to any one of the preceding claims wherein means are provided for maintaining the coupling interconnected after operation of the keying device but before operation of the latching device.

8. A mechanism according to any one of the preceding claims wherein means are provided to disconnect said coupling means upon operation of the latching member by the operating member whereby the keying device must be operated for each release of the latching member by the operating member.

9. An operating mechanism for a lock or latch, constructed and arranged for use and operation substantially as described herein with reference to the accompanying drawing.

10. A lock or latch provided with at least one operating mechanism according to any one of the preceding claims.