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AssigneeDemag Aktiengesellschaft
InventorsFriedrich-Wilhelm Aldag, Robert Hans Scheipner, Helmut Schluessler
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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.
In a power-driven impact tool including an elongated tool drive housing having a flange at its upper end and adapted to receive at its lower end a drive member operative at a predetermined first frequency, and a hand grip assembly coupled to the tool drive housing via a first spring for axial movement with respect to the tool drive housing, the hand grip assembly having at its upper end a hand piece adapted to be grasped by a tool operator, the improvement which comprises, in combination, a second spring surrounding the tool drive housing and having one end carried by the hand grip assembly, and a weighted ring surrounding the tool drive housing and affixed to the other end of the second spring, the characteristic frequency of the subsystem defined by the second spring and the weighted ring being chosen to be equal to the first frequency, whereby the hand piece is substantially isolated from impacts and shaking movements set up by the drive member when the latter is operative.
Dependencies are inferred from the claim text.