| 摘要 |
A dockboard having an improved return-to-dock-level mechanism. The dockboard includes a ramp having its rear edge hinged to the frame of the dockboard and a lip is hinged to the front edge of the ramp and is movable between a downwardly hanging pendant position and an extended position. The ramp is biased to an upwardly inclined position by a counterbalancing mechanism. A holddown mechanism interconnects the ramp and the frame, and permits downward movement of the ramp but prevents upward movement of the ramp unless released through operation of a release lever. A link is pivoted to the underside of the ramp and an arm pivotally connects the link with the lip. The distal end of the link is located forwardly and below the level of an abutment on the release lever when the ramp is at a downwardly inclined position and the lip is extended. Subsequent movement of the lip from the extended position to the pendant position will move the distal end of the link upwardly to engage the abutment and move the release lever to a disengaged position to enable the counterbalancing mechanism to pivot the ramp upwardly to a position slightly above horizontal, in which position, the distal end will move out of engagement with the abutment so that the release lever will return to its engaged position and prevent further upward movement of the ramp.
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