Mine roof supports
AssigneeGullick Dobson Limited
InventorTom C. Bithell
Life of this patent
Estimating the term…
Abstract
Mine roof support comprising a base including a pair of skids, a roof engaging canopy, jacks acting between the base and the canopy, an auxiliary jack connected to the base for lifting or lowering at least part of the base when the support advances and a lost motion arrangement connected between the base and the auxiliary jack for aiding movement of the base and the roof engaging canopy toward each other. The lost motion arrangement is connected to each of the skids by a pivotal connection which permits the front end of one skid to move vertically to a limited extent with respect to the front end of the adjacent skid.
Claims13
A mine roof support comprising:
- a base including a pair of parallel skids each having a front end;
- a roof canopy;
- jack means acting between the base and canopy;
- auxiliary jack means connected to said base for lifting or lowering at least part of said base when the support advances;
- and
- lost motion means connected between said base and said auxiliary jack means for aiding movement of said base and said roof engaging canopy towards each other, said lost motion means being connected to each of said skids by a pivotal connection which permits the front end of one skid to move vertically to a limited extent with respect to the front end of the adjacent skid.
Dependencies are inferred from the claim text.