| 摘要 |
<p>A chassis comprises two legs 11 and 12 extending in parallel spaced apart relationship and a cross member 13 connecting the two legs together. The cross member comprises first, second and third tubular members 14, 16 and 17. The second member 16 is telescopically extendible and retractable in the first member 14 and the third member 17 is telescopically extendible and retractable in the second member 16. A linear actuator 21 is provided for extending and retracting the second and third members in opposite directions relative to the first member. <IMAGE></p> |
