Improvements in Valve Apparatus for Percussive Rock Drills and the like.

摘要

617. Rayner, G. Jan. 9. Fluid-actuated gears.-The valve has three heads, of which the central head O controls the admission, and the end heads 0', O2 control the exhaust. Auxiliary heads H, H1 are formed on the heads O1, O2 and slide in auxiliary cylinders Y which are held in position by screwed valve-chest covers C. Auxiliary passages X, Z are formed in the valve to connect the auxiliary cylinders with the annular recesses in the valve, and ports D, D' are provided at the ends of the valve chamber and communicate constantly with the inlet. The fluid pressure acting on the heads H, H' reduces the locking force on the valve and assists in its reversal. In the position of the valve shown, the valve is locked by fluid-pressure supplied through port D acting upon the annular surface of the head 0', which exceeds and acts against the pressure on the head H1. When the piston passes the port M, the cylinder fluid acts upon the annular surface of the head O2 and reverses the valve. Port B is then put into communication with the exhaust port N, and the port B1 is put into communication with the supply port C. Special auxiliary exhaust ports L, L1 are provided to prevent an accumulation of leakage fluid in the chambers E, E' and so prevent chattering. These ports are open only during part of the valve travel and prevent any compression of air in the chambers E, E1. The valve cylinders Y are renewable and may be made reversible.