| 摘要 |
The hollow, rectangular section tow-bar (1), with front shackle eye (1b), slides axially on guide-shoes (4) within a hollow case (3) fixed to the trailer towing bracket (2). Its rear end (1a) is fixed to the position rod (5a) of the axially mounted ran (5), whose cylinder is fixed to the bracket. Fluid from a reservoir (RE) is forced into the ram front (5b) when an actuator presses the ribbed driving roller of a pump (CH) against a trailer road wheel tyre, with the return electro-valve (RB) closed, thus retracting the tow-bar. Displaced fluid enters the accumulator (AC), returning when the forward end is de-pressurised, lengthening the tow-bar. Pump and valve are controlled from a steering-box sensor. A "fail safe" feature imposes maximum elongation. A proximity sensor is disposed in a protective box. The tow-bar assembly can be variously controlled by a programmable device located in the cab of the vehicle. USE/ADVANTAGE - Optimises capacity of centre axle trailers within maximum permitted overall length.
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