Fluiddosiereinrichtung für ein durch ein komprimiertes Fluid betriebenes Werkzeug

A vibration dampened percussive tool has a handle assembly and a cover surrounding a barrel and piston assembly which are caused to oscillate relatively to the handle assembly. The barrel assembly receives a tool retainer and a trigger controls primary air supply. To reduce air consumption when the tool is not actually applied to a workpiece and thereby to reduce exposure of the operator's hand/arm to vibration, an air metering device is provided, which includes a tube slidably mounted in a bush and having a bleed hole in an end of the tube which enters the bush. In one position of the tube within the bush, apertures in the tube are sealed to allow the tool idle and in another position of the tube the apertures are exposed. The tube connects the air line with the piston assembly and moves within the bush responsive to pressure applied by the actual tool on the workpiece.