| 摘要 |
1,138,716. Automatic steering. HEWITT-ROBINS INTERNATIONAL [S.A. 22 May, 1967 [28 Feb., 1967], No. 23591/67. Heading B7H. [Also in Division B8] Automatic steering apparatus for a selfpropelled bridge conveyer adapted to overlay and be guided by side rails 12a of a fixed conveyer comprises steering cylinders 37, 37a adapted to turn interconnected yokes 20 about vertical axes, which yokes have wheels 14 journalled therein, each yoke being provided with forward and reverse feelers 21, 21a respectively such that when the conveyer is travelling in a forward direction the reverse feelers are retracted and contact of a forward feeler with a rail 12a causes the conveyer to move away from the rail. Each feeler comprises a roller 27 mounted between arms 24, 25 of a first lever 22, and a second lever 23, each lever being pivoted to the yoke and connected by a pin and slot arrangement 28, 29. A spring 32 biases the feeler to its extended position and inward movement of the feeler when it contacts rail 12a causes a cam 34 to contact cam follower 35 such that a valve 36 is actuated to turn wheel 14 from the rail. The feeler is held in a retracted position by an arm 39 of a rotary actuator 57 contacting a pin 38. In the hydraulic circuit shown in Fig. 9, if it is required that the bridge conveyer is to move in a forward direction valve 41 is adjusted so that pressure fluid from a pump PV is supplied via line 43 to a valve 40. The valve 40 allows pressure fluid from a pump 44 to be supplied to wheel motors 46 and via line 43 to the valves 36 associated with the forward feelers. Fluid is also supplied to the actuators 57 so that the reverse feelers are retracted and the forward feelers are free to fully extend. Actuation of a cam follower 35 allows fluid to be supplied to a steering valve 42 which supplies fluid from a pump 48 to steering cylinders 37, 37a, to steer the wheels 14 away from rail 12a. |
