| 摘要 |
A lift table includes a toe sensor responsive to contact around the entire perimeter of the base. Multiple pressure switches are installed over two sides of the base and capped by an overlapping four-sided suspended guard. Multiple guides and springs of appropriate stiffness support the guard suspended over the base, so that any appreciable pressure exerted on the guard causes the compression of the springs and the direct application of pressure on an underlying switch which, in turn, de-energizes the mechanism controlling the descent of the platform. The pressure switches are incorporated into a control circuit that is activated only when the platform is descending. The platform may be sized to extend over the base enough to overlap the guard of the toe-sensor.
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