Improvements in or relating to props, especially pit props

摘要

893,964. Hydraulic pit-props. EGGEMANN, W., and CAMPENHAUSEN, E. VON, [trading as SCHWARZ KOMM.-GES., HERMANN]. Nov. 27, 1958 [Dec. 17, 1957], No. 38228/58. Class 20(2) A pit prop comprising telescoping parts 10, 18 held extended against load by a friction clamp 14 is set by a fluid operated plunger 22 in the lower end of the inner prop part 18 and which operates against the outer prop part 10. As shown this plunger operates against a wedge 13 adapted to be driven into slots 12 in the outer prop part 10 to raise the inner prop part 18 against the mine roof. The fluid for the plunger is supplied by a supply pipe connected to a coupling 30. The clamp 14 comprises a claw 16 driven over the projecting free ends of a clamping collar by a wedge 15.