| 摘要 |
1,157,286. Jib cranes. PHILIPS GLOEILAMPENFABBIEKEN N.V. 13 July, 1966 [13 July, 1965], No. 31503/66. Heading B8B. A derrick comprises a vertical post 1 carrying a pulley 5, a jib 2 carrying a pulley 6 and pivotally supported for luffing movement about a horizontal axis at the base of the post 1, a hoisting rope 10 passing around the pulleys and means for connecting the hoisting rope to the jib so that the rope can be used to luff the jib. The jib can be held in either its upper or lower position by either electromagnetic means or remotely controlled pawl and ratchet means. Alternatively the jib may be bolted in position. When a load 9 has been lifted into the proximity of the pulley 6, the rope is connected to the jib 2 by bolting it between a pair of clamp plates, Fig. 3 (not shown) pivoted to the jib. |
