Hammer drill
AssigneeRobert Bosch GmbH
InventorsManfred Bleicher, Ulrich Bohne, Karl Wanner
Life of this patent
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Abstract
A power driven hammer drill includes a percussive mechanism connectable to driving gears via a clutch. A pressure amplifying lever system is arranged between a movable part of the clutch and shiftable guiding means for a work tool to apply an amplified pressure on the clutch when the work tool is pressed against a workpiece.
Claims10
A hammer drill having a housing and within the housing means for guiding a work tool, a percussive mechanism including an electric motor coupled via a gear train and a rotary motion convertor to a reciprocating driving member, the driving member acting via an air cushion on an axially movable striking member whose energy is transferred to a work tool inserted in said guiding means, a clutch having an axially movable part in mesh with said gear train and an axially fixed part provided on said motion convertor, comprising means for transferring relative axial movement between the work tool and the housing to said movable clutch part to control the connection between said gear train and said motion converter in response to a contact pressure of the work tool against a workpiece, said transferring means including power transforming means for amplifying the effects of said contact pressure on said clutch, said guiding means being displaceable relative to said housing in response to a control pressure of the work tool against a workpiece, and said power transforming means including a lever system arranged between said housing, said guiding means and said movable clutch part so as to amplify pressure transmission from said guiding means against said clutch part.
A hammer drill having a housing and within the housing means for guiding a work tool, a percussive mechanism including an electric motor coupled via a gear train and a rotary motion convertor to a reciprocating driving member, the driving member acting via an air cushion on an axially movable striking member whose energy is transferred to a work tool inserted in said guiding means, a clutch having an axially movable part in mesh with said gear train and an axially fixed part provided on said motion convertor, comprising means for transferring relative axial movement between the work tool and the housing to said movable clutch part to control the connection between said gear train and said motion converter in response to a contact pressure of the work tool against a workpiece, said transferring means including power transforming means for amplifying the effects of said contact pressure on said clutch, said guiding means being displaceable relative to said housing in response to a control pressure of the work tool against a workpiece, said power transforming means including a one-arm lever system arranged between said guiding means and said movable clutch part, one end of said one-arm lever being tiltably supported in said housing, and the other end of said lever engaging said guiding means and an intermediate part of said lever engaging said movable clutch part.
A hammer drill having a housing and within the housing means for guiding a work tool, a percussive mechanism including an electric motor coupled via a gear train and a rotary motion convertor to a reciprocating driving member, the driving member acting via an air cushion on an axially movable striking member whose energy is transferred to a work tool inserted in said guiding means, a clutch having an axially movable part in mesh with said gear train and an axially fixed part provided on said motion convertor, comprising means for transferring relative axial movment between the work tool and the housing to said movable clutch part to control the connection between said gear train and said motion converter in response to a contact pressure of the work tool against a workpiece, said transferring means including power transforming means for amplifying the effects of said contact pressure on said clutch, said guiding means being displaceable relative to said housing in response to a control pressure of the work tool against a workpiece, and said power transforming means including an angle lever having its fulcrum pivotably supported on said housing, one arm of said angle lever engaging said guiding means and the other arm engaging said movable clutch part.
Dependencies are inferred from the claim text.