Abstract: An improved impact-type tool driven by pneumatic or similar power means is provided with a hand grip assembly which is substantially insulated from impact and shaking movements of the drive portion of the tool when the latter is in operation. Both the hand grip assembly and a supplementary weighted ring are disposed coaxially around the tool drive housing and are individually mounted for axial movement with respect thereto. The hand grip assembly is divided into upper and lower chambers by means of an intermediate annular guide member. A first spring disposed in the upper chamber interconnects the hand grip assembly with a flange on the upper portion of the tool drive housing, while a second spring disposed in the lower housing interconnects the hand grip assembly with the weighted ring. The characteristic frequency of the subsystem including the second spring and the weighted ring is chosen to be equal to the normal impact frequency of the tool when the latter is in operation.