Pneumatic percussive tool with a short working drive piston

Abstract

A pneumatic percussive tool for a paving breaker and/or a hammer drill, provided with a drive piston which is axially displaceable both backwards and forwards, comprising a guide sleeve and a piston bottom supporting the guide sleeve. A percussion piston can be displaced axially in the guide sleeve of the drive piston with the piston head thereof in percussive mode. During the transition from percussive to idling mode, the piston head slides out of the guide sleeve in such a way that the percussion piston is substantially maintained in the idling mode in an axially displaceable manner by means a stationary part of the percussion tool housing as opposed to being so maintained in the guide sleeve. The axial length of the drive piston can be reduced, whereby the mass of the drive piston and vibrations caused by the movement of the drive piston in the percussive and idling mode can also be reduced.

Dependencies are inferred from the claim text.