Importance

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Abstract

An electromechanically operated dockboard. The dockboard includes a ramp hinged at its rear edge to a supporting frame and the ramp is adapted to be moved from a generally horizontal cross traffic position to an upwardly inclined position by operation of a recirculating ball screw unit, which is connected between the frame and the ramp and is driven by a permanent magnet motor. A lip is hinged to the front edge of the ramp and can be pivoted from a pendant, downwardly hanging position to an extended position where it forms an extension to the ramp. Deactivation of the ball screw unit, after the ramp is elevated, causes the ramp to fall by gravity, and as the ramp descends, the lip is lifted to the extended position where it will engage the bed of the truck. During the descent of the ramp the ball screw unit is driven in a reverse direction and the permanent magnet motor serves as a brake to control the speed of descent.

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First Claim