Drill

A pneumatic-hydraulic drill comprising

• a. a main housing having a front end and a rear end with an opening extending therethrough from the front end to the rear end;
• b. a hydraulically activated feed cylinder external to said main housing and adjacent to the rear end of said housing, said feed cylinder including a cylinder having a forward end and a rear end and having a central bore that is substantially parallel to said opening of said main housing, said feed cylinder further including an outer piston having an axial bore that extends forwardly from said outer piston, said outer piston at least partially disposed within said feed cylinder, said outer piston configured for axial movement within the central bore of said cylinder;
• c. a pneumatically activated motor, said motor being configured to fit within the opening of said housing, said motor having a forward end and a rear end, said rear end of said motor being attached to the forward end of the rod of said feed cylinder, said axial bore of said outer piston being in fluid communication with said motor to supply pressurized air to said motor, said motor being movable between a rearmost position wherein the outer piston of said feed cylinder is in a retracted position and a forwardmost position wherein the outer piston of said feed cylinder is in said extended position;
• d. a pneumatically operated rotary gerotor pump, said rotary gerotor pump actuated by a first air motor connected thereto, said rotary gerotor pump for pressurizing hydraulic fluid for delivery to said feed cylinder;
• e. a first valve system for controlling the operation of said drill;
• f. A first circuit for supplying air from a source of pressurized air to the axial bore of the outer piston of said feed cylinder, to said rotary gerotor pump, and to said first valve system, and
• g. a second circuit for supplying pressurized hydraulic fluid to said feed cylinder and to said first valve system.