GB2200943A

GB2200943A - A latch mechanism for a vehicle door

Info

Publication number: GB2200943A
Application number: GB8702790A
Authority: GB
Inventors: Marcus John Scott Ward
Original assignee: Ford Motor Co
Current assignee: Ford Motor Co
Priority date: 1987-02-07
Filing date: 1987-02-07
Publication date: 1988-08-17
Also published as: GB8702790D0

Abstract

The mechanism which is operated from inside the door by a Bowden cable 56 has the inner wire 60 thereof passing through a locking lever 24 and to a release lever 22. The locking lever 24 is movable between a locked position in which operation of the release lever 22 is prevented and an unlocked position in which the release lever 22 can be pivoted to lift a paw 20 away from a claw 4 capturing a fixed detent. A compression spring 64 surrounds the wire 60 between the two levers 24, 22. When the wire 60 is pulled by operating a release handle on the inside of the door the release lever 22 will move to compress spring 64 which in turn applies an, unlocking force to the locking lever 24 which is snapped to its unlocked position. if however the locking lever becomes stuck in its locked position the spring force is insufficient but abutments on the levers will engage to unjam the lever 24 - as shown there is an abutment surface 66 on lever 22 and an abutment tang 69 on lever 24. <IMAGE>

Description

Vehicle Door-Latch Mechanism This invention relates to a vehicle door latch mechanism and in particular to a mechanism for a vehicle door lock system in which a single flexible push/pull control cable interconnects a release handle inside the vehicle with the latch mechanism.

k door lock system of this type is described in our European Patent Specification No 0 169 644, and the reader is referred to that specification for further details.

For operation of the latch from inside the door, this lock system depends upon movement of a single releasehandle which operates a release lever in the latch. The opening movement of the release handle is also applied to the locking lever in the latch through a spring which acts between the locking and release levers.

In the event that the locking lever becomes frozen or jammed, possibly resulting from a malfunction of a central locking motor, it is desirable to provide a secondary release mechanism for the locking lever.

According to the present invention therefore there is provided a latch mechanism for a vehicle door, the mechanism including a release lever and a locking lever which is displaceable between a first, locked position in which it prevents operation of the release lever and a second, unlocked position in which the release lev-er can be operated, wherein the latch is connected at one end of a Bowden cable for operation from inside the door, the inner wire of the cable passing through the locking lever and being connected to the release lever, with a compression spring acting parallel to the line of action of the wire, between the locking and release levers, such that when the release lever is moved, the spring is compressed and applies an unlocking force to the locking lever, the locking and release levers being provided with registering abutments so that if the force applied by the compression spring is insufficient to unlock the locking lever, then the release lever abutment will bear against the locking lever abutment so that the force applied through the inner wire will act directly on the locking lever.

The spring is preferably concentric with the wire.

The release lever and the locking lever are preferably formed from flat material and are mounted for pivoting movement in two spaced planes. One lever preferably has a tang bent out of the plane of the lever at one edge and projecting into the plane of movement of the other lever to act as an abutment surface which abuts with an abutment surface on the edge of the other lever.

In one embodiment, the tang is formed on the locking lever.

The invention will now be further described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a view of a latch mechanism in accordance with the invention; and Figure 2 is a view similar to that of Figure 1, but with certain parts omitted for clarity.

It is to be noted that Figure 1 shows only those parts of the mechanism necessary for an understanding of the present invention. In particular, some of the springs which are necessary for proper operation have been omitted from Figure 1, for clarity. Figure 2 shows even fewer parts. More details of the operation. of the latch can be obtained from the European Patent Specification 0 169 644.

The mechanism shown in Figure 1 has a base plate 10 which will be affixed to the edge of a door, with a laterally open slot 12 which will register with a fixed detent (not shown) on the adjacent bodywork of the vehicle.

A claw 14 is mounted on an axis 16 so that it rotates across the slot 12 to capture the detent in a space 18.

When the claw takes up the position shown in Figure 1 (which corresponds to a door closed position), anticlockwise rotation (leading to the door being in a condition where it can be opened) is prevented because the claw is retained by a pawl 20.

The pawl 20 is influenced by a release lever 22 and a locking lever 24. In Figure 1, the locking lever is shown in its unlocked position, and in this position the release lever can be moved in the direction indicated by an yarrow 26 to lift the pawl 20 away from the claw. When this happens, the release lever pivots about an axis defined by a spigot 28 mounted on an extension 30 of the locking lever 24.

In Figure 2, the locking lever is shown by full lines in its locked position and by dotted lines in its unlocked position. In the locked position, the spigot 50 on which the release lever 22 turns is shifted from the position shown in Figure 1 to a position 54, and in the position 54 the pivot is aligned with a cut-out 56 in the release lever. Thus in this position, the release lever cannot move the pawl 20.

From the position shown in Figure 1, the locking lever 24 can- be moved anti-clockwise to the locked position. This movement of the locking lever takes place about an axis 32 and is the result of movement of an auxiliary lever 34 in the direction indicated by an arrow 36. The driving connection between the locking lever 24 and the auxiliary lever 34 is accomplished by a lost motion connection between two spaced ears 38 and 40 on the auxiliary lever and a lug 42 on the locking lever. An overcentre spring 44 which has one end fixed in the base plate 10 and one end engaged in the lever 24 urges the lever to one or other end position.

The latch is operated from inside the door by a Bowden cable 56. This cable has a sheath 58 which is fixed in the base 10, and a wire 60. The free end of the wire passes through a hole in the locking lever 24, and ends in a button 62 which is located under the release lever 22. A compression spring 64 surrounds the wire between the two levers and is braced between the levers.

The latch can also be operated from outside the door, by conventional links connected respectively between a door handle and a lock mechanism and the right hand (as seen in the drawings) ends of the levers 22 and 24.

In operation, the wire 60 is pulled by operating a release handle on the inside of the door. If the locking lever is in the unlocked position (Figure 1), then the wire simply pulls on the release lever which in turn lifts the pawl 20 to allow the door to be opened.

If the locking lever is in- the locked position (Figure 2), then when the wire 60 is pulled, the release lever starts to move and compresses the spring 64 which in turn applies an unlocking force to the locking lever so that the locking lever is snapped over into its unlocked condition before the release lever has moved far enough to lift the pawl 20.

However it can happen that the locking lever becomes stuck in its locked position. If this should happen, then the force exerted by the spring would be insufficient to free the lever. What happens in such a case is that the release lever moves towards the locking lever (the spring 64 is becoming further and further compressed during this movement) until an abutment surface 66 on the release lever contacts an abutment tang 68 on the locking lever.

In this position, further force applied to the wire 60 is applied directly to the locking lever, and should be sufficient to overcome whatever is jamming the lever.

In this way, an override mechanism is provided to ensure that the door latch can be released even if the locking lever should become jammed.

Claims

1. A latch mechanism for a vehicle door, the mechanism including a release lever and a locking lever which is displaceable between a first, locked position in which it prevents operation of the release lever and a second, unlocked position in which the release lever can be operated, wherein the latch is connected at one ends of a Bowden cable for operation from inside the door, the inner wire of the cable paSsing through the locking lever and being connected to the release lever, with a compression spring acting parallel to the line of action of the wire, between the locking and release levers, such that when the release lever is moved, the spring is compressed and applies an unlocking force to the locking lever, the locking and release levers being provided with registering abutments so that if the force applied by the compression spring is insufficient to unlock the locking lever, then the release lever abutment will bear against the locking lever abutment so that the force applied through the inner wire will act directly on the locking lever.

2. A latch mechanism as claimed in Claim 1, wherein the spring is concentric with the wire.

3. A latch mechanism as claimed in Claim 1 or Claim 2, wherein the release lever and the locking lever are formed from flat material and are mounted for pivoting movement in two spaced planes, with one lever having a tang bent out of the plane of the lever at one edge and projecting into the plane of movement of the other lever to act as an abutment surface which abuts with an abutment surface on the edge of the other lever.

4. A latch mechanism as claimed in Claim 3, wherein the tang is formed on the locking lever.

5. A latch mechanism for a vehicle door, substantially as herein described with reference to the accompanying.

drawings.