公开(公告)号：US3991835A

公开(公告)日：1976-11-16

申请号：US531564

申请日：1974-12-11

Applicant: Edward A. Bailey ,  Walter D. Fish

Inventor： Edward A. Bailey ,  Walter D. Fish

IPC: B25D9/14 ,  E21B1/30 ,  E21B1/38 ,  E21C3/24

CPC classification number: B25D9/14 ,  E21C3/04 ,  E21C3/24

Abstract: A fluid operated reciprocating piston rock drill wherein the piston has a stem portion closely slidably received in a guide bushing and the cylinder of the rock drill provides clearance space around the head of the piston.