Braking systems

1. A reverse braking system for a commercial vehicle including sensor means for detecting an object in the path of the vehicle when reversing, means responsive to a signal transmitted by the sensor means for automatic application of the brakes when an object is detected, and means for release of the brakes following automatic application, in which the system further comprises means to determine a first condition that a reverse gear has been de-selected and a second condition that a vehicle parking brake has been applied, said determination means being operatively connected to the brake release means to release the brakes only after the first and second conditions are satisfied.

2. A reverse braking system according to claim 1 wherein the signal from the sensor means is disarmed allowing the brakes to be released only when the vehicle has been taken out of reverse gear and the parking brake has been applied.

3. A reverse braking system according to claim 1 wherein the system further comprises a test means to subject the sensor means, brake application and release means to a self-test protocol when reverse gear is selected, whereby a means of warning the driver if any of said sensor means, brake application and release means is determined by the test means to be malfunctioning.

4. A reverse braking system according to claim 3 wherein, the self test system is configured to indicate to the driver that the system is functioning correctly.

5. A reverse braking system according to claim 3 wherein, the self test system is configured to indicate to the driver that the system is malfunctioning.

6. A reverse braking system according to claim 1 wherein the system includes means to over-ride the automatic brake application means to allow reversing to continue under the direction of the driver of the vehicle.

7. A reverse braking system according to claim 1 wherein the vehicle is an articulated tractor and trailer, the system including trailer-mounted means for automatic application of the brakes when an object is detected by the sensor means, the brake application means comprising a power-operated switch to actuate the brake operating mechanism and a trailer-mounted battery back-up system for supply of power to the switch, in which the tractor is provided with radio transmission means and the trailer is provided with radio receiving means, the receiving means being connected to the battery back-up system to activate the back-up system on receipt of a radio signal from the transmission means.

8. A reverse braking system according to claim 7 wherein the radio signal is transmitted when reverse gear is selected.

9. A reverse braking system according to claim 1 wherein the sensor means is a non-contact sensor.

10. A reverse braking system according to claim 1 wherein the sensor means is a contact sensor.

11. A reverse braking system according to claim 9 wherein said non-contact sensor is an ultrasonic detector.

12. A reverse braking system according to claim 10 wherein said contact sensor is a resilient bumper strip.

13. A reverse braking system for a commercial vehicle including sensor means for detecting an object in the path of the vehicle when reversing, means responsive to a signal transmitted by the sensor means for automatic application of the brakes when an object is detected, and means for release of the brakes following automatic application, in which the system includes means to over-ride the automatic brake application means to allow reversing to continue under the direction of the driver of the vehicle.

14. A reverse emergency braking system for an articulated tractor and trailer, the system including sensor means for detecting an object in the path of the trailer when reversing and trailer-mounted means for automatic application of the brakes when an object is detected by the sensor means, the brake application means comprising a power-operated switch to actuate the brake operating mechanism and a trailer-mounted battery back-up system for supply of power to the switch, in which the tractor is provided with radio transmission means and the trailer is provided with radio receiving means, the receiving means being connected to the battery back-up system to activate the back-up system on receipt of a radio signal from the transmission means.