| 摘要 |
<p>The door is opened by a spring, and closed by hydraulic power. Upon door unlatching, a large spring (2, Fig. 3) pushes a hollow rack (3) to rotate a gear (4) and an arm (5) to open the door. To close the door, fluid is pumped against a piston (7) to return the rack and compress the large spring and a small spring (8). With door latching, fluid pressure is released, and the small spring, abutting a piston rod within the rack, returns the piston to enable subsequent rack movement. The pump's electric motor is controlled by:- a timer to start door closing and reset to zero by traffic stopping on a pedal switch; a latch switch to stop the pump; a fluid-over-pressure switch in case of a body jamming the door; and touch-and-turn-off switches on the door's latch-edge and bottom. Pivoted, spring-biased, anti- clamping plates (20, Fig. 6) cover the gap between the doors hinge- edge and a jamb to prevent a body being clamped. <IMAGE></p> |
