Patent Number: 6,293,357

Title: Hydraulic in-the-hole percussion rock drill

Abstract: A hydraulic reciprocating piston hammer percussion drill includes an elongated piston hammer having opposed reduced diameter shank portions and disposed in a cylinder for reciprocating movement in response to pressure fluid acting continuously on one transverse face of the piston hammer and in response to valving of pressure fluid alternately to an opposed piston face of the piston hammer by a tubular sleeve valve which is disposed in sleeved relationship around the piston hammer between a piston portion of the piston hammer and an impact blow receiving bit. The tubular sleeve valve is provided with ports which communicate with high pressure and fluid exhaust ports in the piston hammer to effect reciprocation of the sleeve valve and of the piston hammer to deliver repeated impact blows to the bit. The bit may be configured to have a major portion of a transverse face disposed at an acute angle with respect to a plane normal to the bit and drill axis to allow directional drilling when the bit receives impact blows without being rotated. Retractable or fixed stabilizer or guide shoe members may be mounted on the exterior of the drill cylinder to aid in centering the drill in the drillhole or allow lateral deflection of the drill to accomplish directional drilling.

Inventors: Patterson; William N. (Montrose, CO)

Assignee:

International Classification: E21B 7/04 (20060101); E21B 7/06 (20060101); E21B 4/00 (20060101); E21B 4/14 (20060101); E21B 004/14 ()

Expiration Date: 09/25/2018