GB2227516A

GB2227516A - Vehicle door latches

Info

Publication number: GB2227516A
Application number: GB8902051A
Authority: GB
Inventors: Wilfrid David Rogers
Original assignee: Bocklenberg & Motte Bomoro
Current assignee: Bocklenberg & Motte Bomoro
Priority date: 1989-01-31
Filing date: 1989-01-31
Publication date: 1990-08-01
Anticipated expiration: 2009-01-31
Also published as: GB8902051D0; DE4000752A1; GB2227516B

Description

1 VEHICLE DOOR LATCHES

Field of the invention.

This invention relates to door latches for motor vehicles andii.n particular,to a central locking system for a motor vehicle which has an improved facility for the provision of dead locking.

Backqround of the Invention.

Many motor vehicle central lockinc systems include latch mechanisms mounted on the vehicle doors, each mechanism having a release lever operable to release the latch mechanism,and a lockinc lever having a locked position in which release of the latch mechanism is prevented and an unlocked position in which release o.." the latch me(zhanism is enab3ed,the lockinc lever beinc movable by an electric actuator between its locked and.-.nlocKed positions.

The lockina lever is also normally connected for operation by a handle,sill button or the like the vehicle such that the locking lever ca.- be moved either 4 is manually or electrically between its locked and unlocked positions.

In order to provide for improved security,it is desirable that any central locking system should provide for dead-locking,i.e. a condition in which the latch locking levers are held in the locked position and can only be moved out of the locked position by operation of a key or equivalent.

It is accordingly an object of the present invention to provide an improved vehicle door latch and a vehicle central locking system which enable dead-locking to be effected in a particularly simple and effective manner.

Summary of the -Invention.

According to a first aspect of the present invention there is provided a vehicle latch mechanism including a release lever operable to release thelatch mechanism,a primary locking lever having a locked position in which release of the latch mechanism is prevented and an unlocked position in which release of the latch mechanism is enabled, an electric actuator for moving the primary locking lever between its locked and unlocked positions and for holding the primary lockinc lever in its locked position,a secondary locking lever movable manually between locked and i i i i i i i i i i 1 i i i i i i 1 -3unlocked positions,and load transfer means acting between the secondary locking lever and the primary locking lever to permit the transfer of a limited load from the secondary locking lever to the primary locking lever.

is The load transfer means may comprise a spring with the arrangement such that,when the primary locking lever is held in its locked position, movement of the secondary locking lever is effected against the action of the spring without being transmitted to the primary locking lever whereas, when the primary locking lever is in its unlocked position or is merely in,as opposed to being held in,its locked position,movement of the secondary locking lever is transmitted to the primary locking lever by the spring to effect corresponding movement thereof.

The primary and secondary locking preferably arranged for the rotation about a with the spring connected to both levers such that, other than when the primary locking lever is held in its locked position,the two locking levers rotate together about said common axis.

levers are common axis According to a second aspect of the presert ibvention there is provided a vehicle central locking system comprising a plurality of latch mechanisms each of which includes a release lever operable to release i i i i the latch mechanism,a primary locking lever having a locked position in which release of the latch mechanism is prevented and an unlocked position in which release of the latch mechanism is enabledran electric actuator for moving the primary locking lever between its locked and i i i unlocked positions and for holding the primary locking lever in its locked position,a secondary locking lever movable manually between locked and unlocked positions, and load transfer means acting between the secondary locking lever and the primary locking lever to permit the transfer of a limited load from the secondary locking lever to the primary locking lever;the system further including control means operable by means of a key or equivalent element to transmit signals to the electric actuators of the latch mechanisms,said signals correspond 1 ing selectively to:

a) movement of the primary locking levers into their unlocked positions, b) movement of the primary locking levers into their locked positions, or c) holding of the primary locking levers in their locked positions.

The electric actuators are preferably electric motors and the means whereby the electric motors are held in their locked positions may be constituted by either i i 1 i mechanical or electrical braking means.

i i i Brief Description of the Drawings.

Figure 1 is a somewhat diagrammatic side view of a motor vehicle door latch, and Figure 2 is a view of the latch at Figure 1.

Detailed Description.

right angles to The latch shown in the drawinas includes a metal housing having its main body portion 10 and a mounting portion 11 disposed generally at right angles to the main body portion. The main body portion 10 provides a pivotal mounting for a generally U-shaped claw or bolt. for engagement with the latch striker. The portion 10 also provides, in generally known manner,a pivotal mounting for a paw] which, when the claw or bolt is moved into its closed position by engagement with the striker,enaages an appropriate formation on the claw or bolt to hold it in its closed position. A release lever is provided for effecting displacement of the paw] ojl, of engagement with the claw or bolt,the release lever being connected to the inside and outside door handles and being selectively connectible to the paw] upon operation of a locking lever. Vehicle latches including such locking and release levers are well known, one example of such a latch being shown in European Patent i i Specification No. 0169644.

Instead of having a single locking lever, the latch of the present invention is characterised in that it has a primary locking lever 12 and a secondary locking lever 13. The primary and secondary locking levers 12 and 13 are carried by.the mounting portion 11 for rotation about a common axisithe mounting for the and 13 also providing a mounting for a having end leg formations connected one t two levers. The spring thus provides function actina between the two levers two levers 12 helical spring each of the a load transfer 12 and I--- such that.if both levers are free to move and a load is applied to one of the levers,both levers will move together about the common axis.

The primary locking lever 12 is connected by a coupling element 14 to the release lever to effect move ment of the release lever between its operative position, in which movement of the inside or outside door handles serves to move the paw] to release the latch,and its inoperative or free-wheel position in which such movement of the door handles is not transmitted to the pawl.The primary locking lever 12 is also connected to the outpult element 15 of an electric motor 16. The o,-",..p-,t element 15 is arranged for linear movement between a lowermost position ( as shown in the drawings) and a raised i i i i 1 i i 7_ C' 1 position in which the primary locking lever 12 is displaced in an anti- clockwise direction about the common axis from the position shown in Figure 1.

The electric motor 16 is arranged for operation by means of a keyoperated mechanism or equivalent signal generator, for example, a coded push-button mechanism.The output element 15 is afforded by the end portion of a rack which is displaced by means of a pinion between the locking position shown in Figure 1 and the raised unlocking position.

The secondary locking lever 13 is connected by a link 17 to a sill button, the arrangement being such that, when the sill button is depressed,the secondary lockina lever 13 is moved into the position shown in Figure 1.

When the sill button is raised, the secondary locking lever 13 is turned in the antjclockwise direction as viewed in Figure 1.

The Key-operated mechanism is such as to provide three positions as follows: - a) an unlocking position in which the oitpul, element 15 is in its raised position, b) a locking position in which the oitpit element 15 is moved into the position shown in Ficure 1, and c) a dead-lock position in which the output element 15 is held in the position shown in Figure 1.

1 f is In either of positions a) and b), the output element 15 can be moved int:o the other position upon actuation of the secondary locking lever 13 by means of the sill button.The spring acting between the two levers 12 and 13 acts,in each of these two positions of the keyoperated mechanism, as a load transfer element transmitting the load applied to the secondary locking lever 13 to the primary locking lever 12 and hence effecting movement of the motor output element 15.

When the key-operated mechanism is turned into position c), the motor output element 15 is braked, either mechanically or electrically,and the primary locking lever 12 is thus held in its locked position. This deadlock condition is such that,regardless of any movement of the secondary locking lever 1-3. by means of the sill button,the primary locking lever 12 will remain in its locked position.The spring acting between the two levers 12 and 13 permits the required movement of the secondary locking lever 13, the rating of the spring being such that the motor output element 15 is held positively in its lowermost position without any distortion thereof. At the same time,howeveL-,the sprina rating is sufficient to ensure positive transfer of movement of the secondary locking lever 12 to the primary locking lever 12,or vice versa,in any condition other than the dead-lock condition.

i i i i i 1 i i 1 i i 1 i 1 i i i i i C) When the sill button is pressed to its fullest possible extent, the secondary locking lever 13 is moved into a position in which it is in abutting engagement with part of the latch housing.1f.therefore,a person wishing to obtain unauthorised access to the vehicle were to apply an overload to the sill button,this overload would be transmitted via the secondary locking lever 13 to the latch housing.The overload would not be transmitted to the primary locking lever 12 to move this into its unlocked condition. Equally, the overload would not be transmitted to the spring interconnecting the primary and locking levers 12 and 13 and would therefore, adverse effect on the latch function.

secondary have no 1 10

Claims

C_ 1 Claims.

vehicle latch mechanism including a release lever operable to release the latch mechanism, a primary locking lever having a locked position in which release of the latch mechanism is prevented and an unlocked position in which release of the latch mechanism is enabled, an electric actuator for moving the primary locking lever between its locked and unlocked positions and for holding the primary locking lever in its locked position,a secondary locking lever movable manually between locked and unlocked positions, and load transfer means acting between the secondary locking lever and the primary locking lever to permit the transfer of a limited load from the secondary locking lever to the primary locking lever.
2. A vehicle latch mechanism as claimed in Claim which the load transfer means comprises
3. A vehicle latch mechanism as claimed in which the primary and secondary locking arranged for rotation about a common axis.
4. A vehicle latch mechanism as claimed in Claim 1, - in a spring.

Claim 2,in levers are p j n which the spring is connected to both levers such that, other than when the primary locking lever is held in its locked position, the two lockina levers rotate together about said common axis.

i i i i i i i i i i 1 i i i i i 1 i 11 C 1
5. A vehicle latch mechanism as claimed in any one of Claims 2 to 4, in which the arrangement is such that, when the primary locking lever is held in its locked position,movement of the secondary locking lever is effected against the action of the spring without being transmitted to the primary locking lever whereas, when the primary locking lever is in its unlocked position or is merely in,as opposed to being held in, its locked position, movement of the secondary locking lever is transmitted to the primary locking lever to effect corresponding movement thereof.
6.A vehicle latch mechanism as claimed in any one of the preceeding claims and substantially as hereinbefore described with reference to and as shown in the 1 is accompanying drawing.
1. A vehicle central locking system which includes a plurality of latch mechanisms as claimed in any one of the preceeding claims.
8. A vehicle central locking system comprising plurality of latch mechanisms each of which includes release lever operable to release the latch mechanism, a primary locking lever having a locked position in which release of the latch mechanism is prevented and an unlocked position in which release of the latch 0 12 mechanism is enabled, an electric actuator for moving the primary locking lever between its locked and unlocked positions and fo r holding the primary locking lever in its locked position, a secondary locking lever movable manually between locked and unlocked positions, and load transfer means acting between the secondary locking lever and the primary locking lever to permit the transfer of a limited load from the secondary locking lever to the primary locking lever; the system further including control means operable by means of a key or equivalent element to transmit signals to the electric actuators of the latch mechanisms,said signals corresponding selectively to:- a) movement of the primary their unlocked positions, locking levers into b) movement of the primary locking levers into their locked positions, or c) holding of the primary locking levers in- their locked positions.
9. A vehicle central locking system as claimed in Claim 8, in which the actuators are electric motors.

claimed in
10. A vehicle central locking system as claim 9, in which each electric motor includes a linearly movable element directly coupled to the primary locking lever.

Published 1990 at The Patent Mice. State House, 68f71 Holborn, London WC1R 4TP. Further copies may be obtained frOM The Patent Office. Sales BrLneh, St Mary Cray. Orpingwn. Kent BR5 3RD- Printed by Multiplex techniques ltd, St Mary Cray, Kent. Con. 1187 i i i i i i i i 1