| 摘要 |
1,261,456. Dock levellers. K. ALTEN. 21 March, 1969 [22 March, 1968], No. 14907/69. Heading B8E. An extension 9, pivoted at 7 on brackets 12 secured to a ramp 1, is automatically pivoted between the position shown and a downwardly folded position, Fig. 4 (not shown), on upward and downward pivoting of the ramp 1 about its pivot 2 by a ratchet gearing mechanism mounted on the ramp. A link 19 is pivoted between brackets 5 on the extension and a link 18 secured to a gear wheel 16. The gear wheel 16 meshes with a gear wheel 15 which, together with the gear wheel 16 is rotatably mounted on a bracket 13. An L-shaped member 21 is rotatably mounted on the shaft of the gear wheel 15, one arm 26 of the member 21 being provided with a pivoted pawl 27 adapted to engage pins 17 on the gear wheel 15, Fig. 3 (not shown), and the other arm 21 being connected by a cable or chain 24 to a fixed anchorage 25. In operation, on raising the ramp from the position shown, the cable 24 will tauten and cause, through rotation of the member 21 and the pawl mechanism, rotation of the gear wheel 15, thereby rotating the gear wheel 16 and link 18 through 180 degrees resulting in downward pivoting of the extension, Fig. 4 (not shown). On subsequent lowering of the ramp 1, the member 21 will rotate back to the position shown under the action of a torsion spring 22. On repeating the cycle, the extension will be returned to the position shown in Fig. 2. |
