GB2073858A

GB2073858A - Motor Vehicle Brake Valve

Info

Publication number: GB2073858A
Application number: GB8108426A
Authority: GB
Original assignee: Wabco Fahrzeugbremsen GmbH
Current assignee: Wabco Fahrzeugbremsen GmbH
Priority date: 1980-03-19
Filing date: 1981-03-18
Publication date: 1981-10-21
Also published as: DE3010490A1; NL8100903A; DE3010490C2; GB2073858B

Abstract

An operating assembly for a vehicle brake valve includes a foot pedal 4 which, when depressed, operated the brake valve to apply the service brake. An electical switch 1 is also operated when the foot pedal is depressed to actuate a further braking device, for example a retarder. To enable the effects of hysteresis in the switch to be reduced and to facilitate access to the switch, a proximity switch is used which is located in a stop 2 on which the pedal rests in its inoperative position. Further stops with proximity switches may be provided. <IMAGE>

Description

SPECIFICATION Motor Vehicle Brake Valve The invention relates to vehicle brake valves and, in particular, to an operating assembly for a vehicle brake valve.

Arrangements are known in which the operating assembly of a vehicle brake valve functions also to actuate a further braking device, for example a retarder, by operating an electrical switch associated with the further braking device.

It may, for example, be required that the electrical switch switches on immediately after operation of the vehicle brake valve or of the foot pedal by which the brake valve is operated and that, when the brake is released, the electrical switch should be switched off again. It is desirable that, as far as possible, the switch should be switched off in the same operating position of the brake valve as that in which it was previousiy switched on and this means that the switching hysteresis of the switch should be as small as possible. It is also desirable that the switch should have a comparatively long service life, despite the unfavourable operating conditions (cold, heat, dampness, vibration) inherent in installation in a vehicle and that, when installed, it should be accessible for servicing purposes.

An object of the present invention is to provide an operating assembly for a motor vehicle brake valve, which enables these requirements to be satisfied.

The present invention provides an operating assembly for the brake valve of a pressure medium-operated brake system of a vehicle, the assembly including a member which is movable to operate the brake valve and which co-operates, in its inoperative position, with a stop, and an electrical switch operable by the said member to actuate a further brake, the switch being a proximity switch which is located in the stop.

The proximity switch may be encapaulated in the stop or may be removably inserted into the stop.

The accompanying drawing illustrates an embodiment of the invention, which will now be described by way of example.

The drawing shows the upper portion 3 of a motor vehicle brake valve (not shown), in which is mounted the valve operating assembly including a foot pedal 4 which is depressed by the vehicle driver when braking. The foot pedal 4 is rotatably mounted on a pivot point 5 and in the inoperative condition is supported on a stop screw 2. A valve operating member extends from the pedal through the upper portion 3 of the brake valve, to be moved downwardly as the pedal is depressed and thereby actuate the brake valve to apply the normal service brake. The manner in which this occurs, and appropriate constructions of the brake valve are well known and need not be described here since they are not essential to an understanding of the present invention.

A further braking device (for example, a retarder) is provided, in addition to the service brake, to be actuated by the brake pedal 4. The further braking device is applied and released in response to operation of an electrical switch in the form of a proximity switch 1 which is built into the stop screw 2. This proximity switch 1 which is shown in the drawing as having a supply line 6 can be of any appropriate known type operating, for example, capacitively, inductively or optically.

The further braking device and the manner in which it is applied or released in response to operation of the switch 1 are not indicated in the drawing and will not be described here since they are well known, and the details of them are not essential to an understanding of the present invention. It is sufficient only to state that the switch 1 is so arranged that the further braking device comes into operation and is released in a desired relationship to the operation of the brake valve: it may, for example, be arranged that the switch 1 switches on immediately after operation of the brake valve or of the foot pedal 4.

The proximity switch 1 is either firmly encapsulated in the stop screw 2 or is removably inserted into the stop screw. This second possibility is especially advantageous because in this case it is possible to exchange the switch without influencing the inoperative position of the foot pedal 4 as defined by the stop screw.

Furthermore, it is also possible to provide several stop screws, each similar to the stop screw 2 and each equipped with a proximity switch in order to control different braking devices.

The use of a proximity switch 2 to control operation of the further braking device is advantageous since the setting accuracy of the switch will remain stable over the whole operating period.

Furthermore, according to the type of proximity switch used it is possible to eliminate switching hysteresis to a great extent and, as a result, the switch 1 will switch on and off in substantially the same operating position of the brake valve.

Finally, the proximity switch can be expected to have a comparatively long service life despite the comparatively infavourable conditions in which it is required to operate when installed on a vehicle.

Claims

1. An operating assembly for the brake valve of a pressure medium-operated brake system of a vehicle, the assembly including a member which is movable to operate the brake valve and which co-operates, in its inoperative position with a stop, and an electrical switch operable by the same member to actuate a further brake, the switch being a proximity switch which is located in the stop.

2. An assembly according to claim 1, in which the proximity switch is encapsulated in the stop.

3. An assembly according to claim 1, in which the proximity switch is removably inserted into the stop.

4. An assembly according to any one of the preceding claims, including at least one further

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Motor Vehicle Brake Valve The invention relates to vehicle brake valves and, in particular, to an operating assembly for a vehicle brake valve. Arrangements are known in which the operating assembly of a vehicle brake valve functions also to actuate a further braking device, for example a retarder, by operating an electrical switch associated with the further braking device. It may, for example, be required that the electrical switch switches on immediately after operation of the vehicle brake valve or of the foot pedal by which the brake valve is operated and that, when the brake is released, the electrical switch should be switched off again. It is desirable that, as far as possible, the switch should be switched off in the same operating position of the brake valve as that in which it was previousiy switched on and this means that the switching hysteresis of the switch should be as small as possible. It is also desirable that the switch should have a comparatively long service life, despite the unfavourable operating conditions (cold, heat, dampness, vibration) inherent in installation in a vehicle and that, when installed, it should be accessible for servicing purposes. An object of the present invention is to provide an operating assembly for a motor vehicle brake valve, which enables these requirements to be satisfied. The present invention provides an operating assembly for the brake valve of a pressure medium-operated brake system of a vehicle, the assembly including a member which is movable to operate the brake valve and which co-operates, in its inoperative position, with a stop, and an electrical switch operable by the said member to actuate a further brake, the switch being a proximity switch which is located in the stop. The proximity switch may be encapaulated in the stop or may be removably inserted into the stop. The accompanying drawing illustrates an embodiment of the invention, which will now be described by way of example. The drawing shows the upper portion 3 of a motor vehicle brake valve (not shown), in which is mounted the valve operating assembly including a foot pedal 4 which is depressed by the vehicle driver when braking. The foot pedal 4 is rotatably mounted on a pivot point 5 and in the inoperative condition is supported on a stop screw 2. A valve operating member extends from the pedal through the upper portion 3 of the brake valve, to be moved downwardly as the pedal is depressed and thereby actuate the brake valve to apply the normal service brake. The manner in which this occurs, and appropriate constructions of the brake valve are well known and need not be described here since they are not essential to an understanding of the present invention. A further braking device (for example, a retarder) is provided, in addition to the service brake, to be actuated by the brake pedal 4. The further braking device is applied and released in response to operation of an electrical switch in the form of a proximity switch 1 which is built into the stop screw 2. This proximity switch 1 which is shown in the drawing as having a supply line 6 can be of any appropriate known type operating, for example, capacitively, inductively or optically. The further braking device and the manner in which it is applied or released in response to operation of the switch 1 are not indicated in the drawing and will not be described here since they are well known, and the details of them are not essential to an understanding of the present invention. It is sufficient only to state that the switch 1 is so arranged that the further braking device comes into operation and is released in a desired relationship to the operation of the brake valve: it may, for example, be arranged that the switch 1 switches on immediately after operation of the brake valve or of the foot pedal 4. The proximity switch 1 is either firmly encapsulated in the stop screw 2 or is removably inserted into the stop screw. This second possibility is especially advantageous because in this case it is possible to exchange the switch without influencing the inoperative position of the foot pedal 4 as defined by the stop screw. Furthermore, it is also possible to provide several stop screws, each similar to the stop screw 2 and each equipped with a proximity switch in order to control different braking devices. The use of a proximity switch 2 to control operation of the further braking device is advantageous since the setting accuracy of the switch will remain stable over the whole operating period. Furthermore, according to the type of proximity switch used it is possible to eliminate switching hysteresis to a great extent and, as a result, the switch 1 will switch on and off in substantially the same operating position of the brake valve. Finally, the proximity switch can be expected to have a comparatively long service life despite the comparatively infavourable conditions in which it is required to operate when installed on a vehicle. Claims

4. An assembly according to any one of the preceding claims, including at least one further stop for the said member, each of the further stops including a respective proximity switch.

5. A operating assembly for a vehicle brake valve, substantially as described herein with reference to, and as shown in the accompanying drawing.