| 摘要 |
<p>A car transporter lorry has a movable upper platform supported by four posts, each post housing a screw which may be motor driven. The upper platform is coupled to the screw to be raised and lowered as they rotate. The drive is pref. by hydraulic motor (3), and there may be a screw in each post or in each of the rear posts only. A single hydraulic motor is used to drive two screws, and is supported on the chassis of the lorry between its respective pair of posts. The screws are more reliable and harder wearing than a cable mechanism to raise and lower the upper platform. The support posts can be made thinner than if hydraulic cylinders and pivoted posts were used, safety pins are not needed to hold the posts in place.</p> |
