| 摘要 |
966,740. Self-erecting tower cranes. ETABBLISSEMENTS WEITZ S.A. SOC. LES FILS DE JULES WEITZ, CHANTIERS & ATELIERS DE CONSTRUCTION DE LYON, WEITZ, REUNIES. April 6, 1962 [April 6, 1961], No. 13396/62. Heading B8B. A tower crane is erected by raising the jib 4, Fig. 2, from a horizontal inverted position on the ground to a vertical position alongside a base member 1 of the tower so that the jib and hoisting tackle may be used to position additional tower elements 12. The jib is pivoted to a frame 13 which embraces the tower and in co-operation with guides on the lower part of the jib allows the jib to be slid up the tower in steps as it is lengthened. When the desired height is reached the jib is rocked into a horizontal position, Fig. 4, about a pivot 18 on the frame 13 by a lifting cable 10 which is attached to the base 3. Further sections may be added as the work progresses, this being facilitated by tilting the jib to the right or left in a vertical position about its slewing mechanism which is pivoted to the frame 13. |
