| 摘要 |
<p>A crane comprises a first arm (8) pivotably arranged on a frame (2) about a substantially horizontal axis (9), a second arm (12) pivotably arranged on the first one about a substantially horizontal axis (11), a load (27), for example a tool, being intended to be carried by the second arm, and an arrangement for maintaining the arms (8, 12) in desired relative positions with respect to the frame (2) and each other. The arrangement comprises connecting members (14, 19) connecting each arm to a bearing arrangement (17, 18) arranged to bear upon and be displaceable along a support surface (7') on the frame (2), so that in every position assumed by the arms the torques generated by the forces emanating from the weights of the load and the arms with respect to the two pivot axes (9, 11) mentioned above are balancing each other.</p> |
