GB2200397A - Push-button lock - Google Patents

Abstract

A push button lock has a shock absorber in the form of a pad 40 of elastic material between the push button/lock assembly 12 and its housing 10. This pad absorbs excessive axial force applied to the push button. The lock has an over-centre mechanism so that a latch actuator 32 is driven to either one or the other end position, one end position being a locked position and the other end position being an unlocked position. The lock housing is constructed with a support 52 for holding a latch operating arm 44 and is arranged so that the housing 10 can be inserted, completely assembled, from one side of an aperture in a vehicle body panel 16. <IMAGE>

Description

PUSH-BUTTON LOCK This invention relates to a push-button lock as used, for example, on the boot lids or tailgates of motor vehicles.

The invention is particularly concerned with locks operated by a "deadlock". In this specification, the term deadlock means a type of lock in which the tumblers or wards are not influenced by springs, and in which alignment of the tumblers or wards takes place upon rotation of the correct key in the lock.

Thieves often attempt to enter a vehicle by exerting excess force on the push-button to force the button through its housing and so to release the latch which holds the boot lid or tailgate closed. Various measures have been proposed to prevent such attacks being successful, and one such measure is desk jibed in our British Patent Specification 2 165 295 A.

According to the invention, there is provided a pushbutton lock comprising a housing, a push-button mounted in the housing for axial movement against the pressure of a compression spring acting between the housing and the button, a key-operated lock barrel incorporated in the push-button, and a latch actuator mounted at the remote end of the housing, wherein a shock-absorbing material is mounted between the housing and the button to absorb the shock of an axially directed impact attack on the lock.

The spring preferably acts between an outwardly directed shoulder on the push-button and an inwardly directed shoulder on the housing. The shock-absorbing material may be placed on one of these shoulders, so that it is located between the shoulder and the appropriate end of the spring. For example, the material may be a ring of elastic material such as polyurethane, about 3 mm thick.

The lock barrel preferably contains the mechanism of a deadlock (as hereinbefore defined). The latch actuator is preferably eccentric relative to the axis about which the barrel is turned by the key, so that in one lock position, pressing of the push button causes the actuator to actuate a latch and in another lock position, pressing of the push button has no effect on the latch.

There is preferably an over-centre spring between the barrel and the latch actuator which biases the actuator to one or other of two end positions, one end position being that in which the actuator is able to actuate the latch and the other being that in which pressing of the push-button has no effect on the latch.

There may be a lost-motion connection between the barrel and the actuator to allow the initial rotation of the key, which is necessary to align the wards, to take place without any corresponding driving of the actuator.

The housing may include an arm for supporting a latch operating member, and the arm is preferably constructed integrally with the housing and extends generally parallel with the housing axis. In this way, the lock together with the arm can be mounted in the body panel which makes up the boot lid or tailgate by inserting a pre-assembled unit through an aperture in the panel, from one side only of the panel.

The invention will now be further described, by way of example, with reference to the accompanying drawings, in which: Figure 1 shows a section through a lock in accordance with the invention; Figure 2 is a section on the line A-A from Figure 1; Figure 3 is a rear perspective view of the lock shown in Figures 1 and 2; and Figure 4 is a section on the line B-B from Figure 1.

The lock shown in Figure 1 comprises a housing 10 which contains a push button assembly 12. The front end of the housing (the right hand end as seen in Figure 1) has a lip 14 by which it can be gripped and a central bore through which the front end of the assembly 12 is accessible. As shown in Figure 1, the housing is fitted into an aperture in a vehicle body panel 16, with a gasket 18 between the housing itself and the outer surface of the panel. The housing will be clipped into position by a suitable clip (not shown) behind the panel 16.

The assembly 12 fits into the bore down the middle of the housing 10 and has an opening 20 at its front end for entry of a key. The key enters a barrel assembly shown in outline at 22 and turning of the key in the lock causes a locking bar 24 to be moved inwards thus allowing a barrel 20 22 to rotate within the rest of the assembly 12.

The lock mechanism is of the deadlock type, ie the wards or tumblers in the lock are not spring-biased and they are moved to their 'free' position by rotation of the correct key in the lock. Such locks are known, and the mechanism will not be described here.

The assembly 12 is held in position in the housing by means of a cup member 28 which fits over the rear end of the housing 10 and has arcuate apertures through which barbed lugs 30 on the assembly 12 project.

The cup 28 also incorporates a latch actuator 32 which has an operating tip 34 eccentric relative to the axis of rotation of the-barrel 26. A driving connection between the barrel 26 and the latch actuator 32 is achieved by means of a flat 36 on the end of the barrel which engages in a suitably shaped recess in the actuator 32. This is shown in more detail in Figure 2, where it will be seen that the recess in the actuator 32 is cut away to allow the barrel 26 to rotate through 45 without any movement of the latch actuator resulting.

This 45 of free movement or lost motion allows the barrel 26 to ret-urn to the vertical position to allow the key to be extracted, leaving the actuator 34 in either the unlocked or locked position.

Irrespective of whether the lock has been unlocked by the key or not, the assembly 12 can be pressed axially into the housing. This axial movement takes place against the force of a coil spring 38 so that the spring is compressed. In normal operation, this pressure would be applied by the thumb when the boot lid or tailgate is being opened. It may however happen that a thief attempts to break into the vehicle by destroying the lock, and to this end he may apply an exceptionally large force to drive the assembly completely through the housing. In order to prevent this happening, a pad 40 of elastic material, preferably a ring of polyurethane material, is placed between the spring 38 and a shoulder 42 in the housing. The energy applied through excessive impacts on the front end of the assembly will then be absorbed, partly by the spring 38 but also significantly by the resilient pad 40.The pad 40 thus absorbs any shocks applied in this way.

The difference between the locked and unlocked conditions of the lock is the position of the latch actuator 32. In one position (this is the position shown in Figure 3) the actuator tip 34 will hit a latch operating lever 44 when the button is pressed in, and this will cause a remote latch to be operated. However in the other (locked) position, the latch actuator will miss the operating lever 44 when it is pushed in, and thus there will be no operation of the lock.

The latch actuator 32 is held in one or other of these end positions by an over centre spring 46 which acts between the actuator and the assembly 12. The action of this spring can be more clearly seen from Figure 4 which is a section on the line B-B from Figure 1. The spring is a wire spring bent into the shape shown in Figure 1 and having one end received in a groove 48 in the inner surface of one of the lugs 30 of the assembly 12. The other end of the spring is received in a hole 50 in the latch actuator 32. In use, the actuator 32 rotates relative to the lug 30 and Figure 4 shows the position of the hole 50 in the actuator 42 in solid lines in one end position and in dotted lines in the opposite end position. When the actuator moves between these two end positions, the straight line distance between the ends of the spring is reduced, thus producing an over centre action which tends to push the actuator to either one or other end position.

The shock absorbing elastic pad 40 may be of polyurethane material, 2 to 3 millimetres thick and having a hardness of 80 to 85 Shore A.

In order to enable the lock to be assembled to the panel 16 from one side, a supporting arm 52 is moulded integrally with the housing 10 and lies wholly within a cylindrical envelope which will pass through a hole in the panel. The whole of the lock mechanism can thus be preassembled and just pushed through the aperture in the panel 16 and secured there by a suitable clip.

Subsequently the latch operating rod 56 is connected to the lever.

Where a central lucking mechanism is fitted, an additional lug 58 is provided on the latch actuator 32 and is connected through a rod 60 to a conventional actuator 62. This enables the actuator 32 to be rotated between its locked and unlocked positions either by a key or by the central locking mechanism. The actuator configuration shown in Figure 2 allows this action through the allowable lost motion between the actuator 32 and the barrel 26. Were it not for this lost motion, the central locking actuator 62 would be attempting to rotate a locked barrel.

Claims (10)

1. A push-button lock comprising a housing, a pushbutton mounted in the housing for axial movement against the pressure of a compression spring acting between the housing and the button, a key-operated lock barrel incorporated in the push-button, and a latch actuator mounted -at the remote end of the housing, wherein a shock-absorbing material is mounted between the housing and the button to absorb the shock of an axially directed impact attack on the lock.

2. A lock as claimed in Claim 1, wherein the spring acts between an outwardly directed shoulder on the pushbutton and an inwardly directed shoulder on the housing.

3. A lock as claimed in Claim 2, wherein the shockabsorbing material is placed on one of the shoulders, so that it is located between the shoulder and the appropriate end of the spring.

4. A lock as claimed in any preceding claim, wherein the shock-absorbing material comprises a ring of elastic material with a thickness of 2 - 3 mm.

5. A lock as claimed in any preceding claim, wherein the lock barrel contains a deadlock (as hereinbefore defined) mechanism.

6. A lock as claimed in any preceding claim, wherein the latch actuator is eccentric relative to the axis about which the barrel is turned by the key, so that in one lock position, pressing of the push button causes the actuator to actuate a latch and in another lock position, pressing of the push button has no effect on the latch.

7. A lock as claimed in any preceding claim, wherein an over-centre spring is provided between the barrel and the latch actuator which biases the actuator to one or other of two end positions, one end position being one in which the actuator is able to actuate the latch and the other being one in which pressing of the push-button has no effect on the latch.

8. A lock as claimed in Claim 5, wherein there is a lost-motion connection between the barrel and the actuator to allow the initial rotation of the key, which is necessary to align the wards, to take place without any corresponding driving of the actuator.

9. A lock as claimed in any preceding claim, wherein the housing includes an arm for supporting a latch operating member, and the arm is constructed integrally with the housing and extends generally parallel with the housing axis.

10. A push-button lock substantially as herein described with reference to the accompanying drawings.