| 摘要 |
779,531. Jib cranes. ELLIOT, T. Dec. 14, 1955 [Sept. 15, 1954], No. 26730/54. Class 78 (4). A crane for use in slating a roof comprises a socket 6 which swings in a vertical plane relatively to a base 4 secured to the roof to be slated and which carries a slewing tubular mast 11 supporting a jib 16 and tie 17. Adjustable arms 13 guy the mast to the roof. The hoist rope 23 is carried clear of the guttering by an outrigger pulley 10 on a pivoted arm 9 and then passes over a pulley 8 through the interior of the mast 11 and over pulleys 18, 17a. The telescoping guy 13 is locked by a pin 14 and, like the base 4, is secured to the roof by hooked bolts 24 engaging a rod 25 positioned below the roof joists. A timber block 26 holds the outrigger pulley 10 off the gutter. |
