The invention relates to a portable impact tool including a housing with at least one handle for manual support of the tool, an impact mechanism movably supported in the housing and having a forward open end for receiving a working implement and a rear end located inside the housing, wherein the impact mechanism is arranged to deliver hammer blows to the working implement attached to the tool.
In impact tools of the above type there has always been a problem to minimize vibrations to which the operator is exposed. A common way to reduce vibration transfer from the impact mechanism to the housing is to arrange the latter longitudinally displaceable relative to the housing and to employ resilient spring elements for absorbing vibrations and conveying feed forces applied on the housing during operation of the tool. However, the vibrations generated in the impact mechanism are not only longitudinally directed but to some extent transverse, and conventional arrangements with a slidable impact mechanism are not effective enough to protect the operator from the exposure to transverse vibration movements. A prior art device of this type is disclosed in for instance U.S. Pat. No. 2,899,934.
An impact tool with an alternative impact mechanism support means is disclosed in U.S. Pat. No. 5,025,870. In this tool the impact mechanism is movably supported in the housing by a pair of parallel links which are pivotal relative to the impact mechanism and the housing via parallel pivot axes. By this arrangement the impact mechanism is movable relative to the housing in a parallel manner to permit longitudinal vibrations to be absorbed. However, there is no freedom provided for the impact mechanism to enable absorption of pivoting movements of the impact mechanism resulting from transverse vibration forces in the working implement.
USPTO Backgrounds
USPTO Backgrounds