Operating system for hydraulic rock drill

An operating system for a rock drill consisting of a housing a single inlet and a single exhaust connection, an impact piston, an internal fluid reservoir, and a rotation motor, wherein

• a. all fluid entering said single inlet connection flows sequentially, in series, from said impact piston through said internal fluid reservoir to said rotation motor;
• b. said fluid reservoir is the only fluid supply source for said rotation motor;
• c. all fluid flowing from said fluid reservoir through said rotation motor exits through said single exhaust connection;
• d. said impact piston is driven toward impact by pressure acting against a drive shoulder and is retracted by pressure acting against a return shoulder, whereby said drive shoulder exhausts fluid into said fluid reservoir during retract;
• e. flow requirements of said rotation motor are matched to flow requirements of said impact piston so as to utilize all of the exhaust flow from said impact piston for rotation,
• whereby continuous and simultaneous impact and rotation occurs under all drilling conditions wherein adjustable bypass means is incorporated between said single exhaust connection to divert a percentage of fluid flow around said rotation motor and thus regulate the speed of said regulation motor.