| 摘要 |
<p>1,262,555. Counterbalancing dockboard ramps. KELLEY CO. Inc. 18 Sept., 1969 [23 Oct., 1968], No. 46137/69. Headings B8B and B8E. A counterbalancing mechanism for a dockboard ramp 9 pivotally mounted at 14 to supporting structure within a pit in the dock 1, comprises an angled lever arm 31 secured to the pivoted rear edge of the ramp and depending into the pit for connection to a spring 19 associated with the support structure such that the spring force substantially balances the changing moment of the ramp throughout the arcuate movement thereof. The coil spring 19 is mounted in a tube 20 secured to the support structure and is compressed between one end 22 of the tube and a retainer 23 secured to the end of a rod 28 which extends axially through the spring for pivoted connection to the lever arm 31. The pivotal connection for the ramp comprises laterally spaced pivot points including elongated slots 11 which facilitate lateral inclination of the ramp if necessary.</p> |
