| 摘要 |
An improved counterbalancing mechanism for an edge-of-dock dockboard. The dockboard comprises a frame mounted on a loading dock and one end of a center plate is pivotally connected to the frame. A lip is hinged to the opposite end of the center plate and is movable between a downwardly hanging pendant position and an extended position where the lip forms an extension to the center plate. A counterbalancing mechanism includes a first link pivotally connected to the center plate, and a second link pivotally connected to the lip. The opposite ends of the links are connected together, and a counterbalancing mechanism, such as a spring, interconnects the first link and the frame of the dockboard. The linkage is constructed and arranged so that when the center plate is in a horizontal storage position and the lip is pendant, the force of the counterbalancing spring will urge the lip in toward the dock. When the lip is manually elevated, the counterbalancing spring will assist in pivoting the center plate from the horizontal to the vertical position and then assist in pivoting the lip to the vertical extended position. In the operational position of the dockboard, in which the extended lip rests on the bed of the truck, the force of the counterbalancing spring aids in maintaining the lip in the extended position.
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