Hammer drill, comprising special arrangement of differential piston and control element

摘要

A return valve (30) is covered by a cap (11) screwed to the outer shaft (15). An inner sleeve (70) attached to the outer shaft (15) accommodates a main body (51) holding a control element (40) with several air passages (48) and forming an annular space (60) with the outer shaft (15). The drill head (90) is moved by a hammer ram (75) designed as a differential piston. The upper segment of the piston (75) forms a sliding valve with the control element (40), the narrow lower end closing a circular gap (96) surrounding the drill head (90) with its outer surface.