Double-piston rock drill

Patent 4036309 Issued on July 19, 1977. Estimated Expiration Date:

July 19, 1994. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.

Abstract Claims Description Full Text

Patent References

841139

1039704

1932259

Inventors

Application

No. 05/664000 filed on 03/04/1976

US Classes:

173/103, Concentric91/186, Connection includes toothed gearing or rocking lever91/533, Single valve for plural rigidly connected working members92/33, Element extends through working member portion92/65Rigid stem on first working member portion extends through second working member

Examiners

Primary: Purser, Ernest R.
Assistant: Pate, III, William F.

Abstract

A rock drill has a housing accommodating pistons defining working chambers. Rotary drive of a drill steel has an overrunning clutch and a screw pair. The screw pair is arranged between the pistons and is formed by outer and inner helical threads respectively provided on these pistons. One of the pistons is kinematically connected with the housing, and the other piston which cooperates, during the drilling, with a chuck receiving the drill steel shank is in force transmitting connection with the rotary drive of the drill steel.The invention is aimed at lowering vibration of the rock drill housing by arranging the screw pair of the rotary drive between the pistons.