MINE ROOF SUPPORTS

专利名称：MINE ROOF SUPPORTS发明人：JEFFREY WILLIAM SEDDON,JACK

WALLWORK BELL

申请号：US3534559D申请日：19681125公开号：US3534559A公开日：19701020

摘要：1,234,661. Advancing mine roof supports. GULLICK DOBSON Ltd. 19 Nov., 1968[17 Jan., 1968], No. 2478/68. Heading E1P. In an advancing mine roof support framehaving a cantilever extension 12 adapted to be reciprocated by a ram 15 the extension isadapted to be urged into engagement with the roof in any position between maximumand minimum extension by a second ram, see Fig. 8 (not shown) or a second plunger inthe ram 15 acting on a wedge 21. The extension may be resiliently bonded by a bow-spring, see Fig. 6 (not shown). For details of ram 15 and its operation, Fig. 4 (not shown)and the Specification should be referred to.

申请人：GULLICK LTD.

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