BRIEF DESCRIPTION OF THE DRAWINGS
The drawings show:
FIG. 1 a side, partially cross-sectional view of a hand-held power tool according to the present invention; and
FIG. 2 a longitudinal cross sectional view of the percussion mechanism of the power tool shown in FIG. 1.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
A hand-held power tool 1 according to the present invention and which is partially shown in FIG. 1, drives, rotationally and percussively, a working tool 3 along an axis A. The working tool 3 is received in a chuck 2 of the power tool 1. The working tool 3 is driven by a percussion mechanism 4 that includes a percussion piston 7 displaceable in a guide tube 5 and reciprocatingly driven by an air spring 6. At its working tool side, the percussion piston 7 impacts an anvil 8 which is axially displaceable, within certain limits and which applies axial blows to the working tool 3.
As shown in FIG. 2, a viscoelastic damping member 9, which is formed of vinylidene-fluoride-hexafluoropropylene (VF2/HFP) in form of an O-ring, is arranged with its radially outer portion in a radially inner groove 10 which is formed in the guide tube 5. The damping member 9 is axially supported in the groove 10 with an annular disc 11. The damping member 9 engages, with its annular thickness R that amounts to a quarter of the diameter D of the anvil 9, radially inwardly, in a circumferential radial groove 13 of the anvil 8 and which is axially limited by opposite axial boundaries 12. The axial length L of the groove 13 corresponds to the diameter D of the anvil. In the shown, in FIG. 2, end operational condition of a hammer blow, the displacement of the anvil 8 in the power tool direction is damped, with the working tool-side axial boundary 12 being pressed against the damping member 9, viscoelastically deforming the damping member 9. Thereby, the motion energy of the anvil 8 is dissipated in the damping member 9.
Though the present invention was shown and described with references to the preferred embodiment, such is merely illustrative of the present invention and is not to be construed as a limitation thereof and various modifications of the present invention will be apparent to those skilled in the art. It is therefore not intended that the present invention be limited to the disclosed embodiment or details thereof, and the present invention includes all variations and/or alternative embodiments within the spirit and scope of the present invention as defined by the appended claims.
Patent Application
20080029283
