| 摘要 |
<p>Lifting mechanism has a platform (6) capable to serve as tailboard for a lorry and carried by two pivoted (9,11 and 10,12) rods (7,8) forming a parallelogram, of which the lower rod (8) is, at its lower end, pivoted to a lever (20), which itself is pivoted (21) to the support (5) and which carries the trunnion end (19) of an hydraulic cylinder (15,17) acting on (18) the lower rod (8) near the platform. The effective length of the lower rod (8) can be increased and it can be locked (33) in its shorter portion in which it has the same length as the upper rod (7). The lower end (12) of the rod (8) is pivoted to a swivel element and, when under load, bears on and is guided by a cam track (32) on the lever (20). The locking element is a latch (33) capable of retaining the lower pivot (12), thus preventing the rod (8) from extending beyond its shortest length.</p> |
