| 摘要 |
752,476. Gin poles for raising derrick masts. MOORE CORPORATION, L. C. March 18, 1954 [Oct. 9, 1953], No. 7893/54. Class 78 (4). A gin pole 1, Fig. 1, is supported in its erect position by a jointed brace 10 comprising struts 16, 17 pivoted together at 21 and provided with a catch for retaining them in alignment. The catch comprises a latch 27, Fig. 4, pivoted at 26 to a tongue 19 on the strut 17 and formed with a notch 31 adapted to embrace a lug 23 on the tongue 19 and a bar 22 bridging a pair of forks 18 on the strut 16. A compression spring 35 on a pin 33 secured to the tongue 19 engages an apertured member 30 bridging two plates which form the latch 27 to bias the latch into its locking position. The plates forming the latch 27 are also bridged by blocks 28, 29 to which is secured a bail 38 carrying a line 37 by which the latch is released and the joint 21 broken when the gin pole is to be lowered. The gin pole is carried on a structure 6, 7, 13, 14, Fig. 1, and comprises spaced legs 1 joined at their upper ends by a lattice structure (not shown) and by a cross member which carries sheaves 3 for engagement by the usual sling for raising the gin pole. |
