| 摘要 |
PCT No. PCT/SE90/00294 Sec. 371 Date Nov. 13, 1991 Sec. 102(e) Date Nov. 13, 1991 PCT Filed May 7, 1990 PCT Pub. No. WO90/14302 PCT Pub. Date Nov. 29, 1990.A crane comprising a rigid column pivotally mounted on a support structure, an arm section connected to the column and comprising two arm portions which extend substantially parallel with one another, a maneuvering device which acts between the arm portions, a rocker arm which is mounted for pivotal movement in one plane on the end of the arm section distal from the column and the free end of which rocker arm is intended to carry a lifting device, tool or the like, wherein the other ends of the mutually parallel arm portions are mutually spaced apart and are connected with a yoke for pivotal movement in the aforementioned plane. The invention is characterized by a carrier arm which is connected at one end thereof to the column for pivotal movement in the aforementioned plane and the other end of which carrier arm is connected to the arm section for pivotal movement in the aforementioned plane by a journal shaft separated from the journal shafts of the parallel arm portions on the yoke. A first piston-cylinder maneuvering device is mounted between the column and the yoke and a second piston-cylinder device maneuvering device is mounted between the column and the carrier arm. |
