| 摘要 |
959,291. Telescopic pit props. K. GERLACH, and H. GERLACH. Nov. 28, 1960 [Nov. 26, 1959], No. 40846/60. Heading E1E. A telescopic pit prop is provided with a friction lock 3 incorporating a wedge 4 and a swivel bearing 7 which pivots about on axis disposed longitudinally of the prop and slides about a concave surface 9 in the prop member 1. The member 7 is provided with a cam 11 and circumferentially-extending slots 14 defining narrow slide surfaces which may in a modification be defined by weld beads. The member 1 is made of steel and may be wedge-shaped whilst the swivel bearing is made or coated with silicon-bronze or incorporates fillets thereof in the slots 14. Specifications 737,661 and 777,568 are referred to. |
