| 摘要 |
A hammer mechanism for a hand-guided machine tool, in particular for a rotary hammer, percussion hammer, or impact drill, has a drive piston ( 11 ), which is supported so that it is able to move axially in a guide tube ( 13 ) and is able to be motor driven via a gear mechanism ( 17 ) into a reciprocating, axial stroke motion, and has a hammer that is contained in an axially movable fashion in the guide tube and acts on a tool and, together with the drive piston ( 11 ), delimits a compression chamber in which an air cushion is enclosed. In order to be able to freely embody the chronological curve of the stroke path of the drive piston ( 11 ) for optimization purposes, e.g. to reduce pressure peaks in the compression chamber, the gear mechanism ( 17 ) has two meshing nonround gears ( 18, 19 ), whose rotation axes ( 20, 21 ) are situated a fixed distance (a) apart from each other. The one driving nonround gear ( 18 ) is able to be motor driven and the other nonround gear ( 19 ), which is driven by the driving nonround gear ( 18 ), has a piston rod ( 23 ), which is connected to the drive piston ( 11 ), linked to it, eccentrically in relation to its rotation axis ( 21 ) (FIG. 2 ).
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