| 摘要 |
The stair-climbing device is suitable for transporting a load up or down a flight of steps. The device includes a frame on which the load is seated and a number of load-bearing shoes which engage successive steps in the flight of steps to produce displacement of the device along the flight of steps. The shoes are pivotally connected to sprocket chains which are activated by a reversible electric motor. An arm is pivotally connected to the frame and is provided with a sensing head disposed forward of wheels on which the device rolls. As the device rolls forward on the tread of a step, the sensing head contacts the tread until it is beyond the forward edge whereupon the head falls with resulting pivotal movement of the arm. The arm is further provided with a downwardly facing friction surface which is spaced above the tread when the sensing head is in contact therewith and which descends into contact with the tread when the arm pivots and thereby frictionally retards further forward movement of the device on the tread.
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