| 摘要 |
1,136,876. Braking systems for vehicles. SOC. ANON. ANDRE CITROEN. 2 May, 1967 [9 May, 1966], No. 20252/67. Heading F2F. A braking system for articulated vehicles comprises three separate fluid-pressure systems for the tractor front brakes, tractor rear brakes and trailer or semi-trailer brakes respectively, the apportioning of the braking effort between the front and rear brakes of the tractor being varied by a compensating bar and roller in accordance with the load on the rear axle. In the figure an hydraulic system with main reservoir 5 controls the tractor brakes 26, 29, and a pneumatic pressure system with reservoirs 59, 61 controls the trailer brakes 69. If the trailer is not coupled, the load on the tractor rear axle 39 will be light, and linkage 41-49 moves a roller 38 to the left (as shown). Depression of the brake pedal 37 then causes the first slide valve 21 to move downwards to connect lines 16 and 25. Pressure in reservoirs 9 and 11 is then communicated to the front brakes 26 and via line 25a to an auxiliary piston 27 on the rear brakes, producing a full application of the front brakes and a partial application of the rear brakes. If the rear axle 39 is loaded, e.g. if a trailer is connected, the linkage 41-49 moves the roller 38 to the right. Depression of the brake pedal 37 then moves a second slide valve 32 downwards to connect lines 18 and 53. Pressure in reservoir 14 is then communicated via line 53 to an hydraulic actuator 54 which opens an air valve 55 in the trailer braking system allowing compressed air from reservoir 58 to actuate the trailer brakes 69. Subsequently, the first slide valve 21 operates as before to actuate the tractor brakes. A third slide valve 33 in the same bore as the second is separated from it by a chamber 40 which communicates with line 53. When the pressure in this chamber rises sufficiently, valve 33 moves downwards to connect lines 17 and 72 and allow pressure in reservoirs 12 and 13 to be communicated to a main piston 73, thus producing a full actuation of the tractor rear brakes. Modifications.-The trailer braking system may be vacuum instead of pressure, operated from a vacuum pump or engine induction pipe. The tractor braking system may also be pneumatic. The brakes may be drum or disc. The auxiliary piston 27 on the tractor rear brakes may be omitted. The valves 32 and 33 may be in separate bores. |
