| 摘要 |
901,116. Erecting tower cranes. PINGON, P. J. Jan. 30, 1961 [Feb. 12, 1960; Aug. 8, 1960], No. 3463/61. Class 78 (4). An end element 1, Fig. 1, of a tower crane is raised, so that an additional standard section may be added to the tower, by a screw 10 axially rigid with the end element and a nut 12 attached to a member 13 which bears on the top of the tower. As described, the screw 10 is attached to the lower end of the end element 1 by a ball-bearing 28, Fig. 4, and a thrust bearing 29 and to the upper end by similar bearings 32, 33. The nut comprises members 38, 39 bearing rollers 42, 43 which run in U- shaped angle members 25 attached to one side of the end element 1. A cross member 11 rigid with the nut bears against the upper part of the crane mast. The screw is driven by the slewing gear 5, Fig. 6, and can also be used for raising and lowering the tower about a pivot 18, a strut 19 holding the nut 12 fixed relative to a point 20. |
