Hammer drill
AssigneeRobert Bosch GmbH
InventorsUlrich Ranger, Karl Wanner, Johann Kaltenecker, Manfred Hellbach, Gerhard Meixner
Life of this patent
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Abstract
A power hammer drill includes a tool holder and an air cushion striking mechanism for driving a tool and including a striker, a reciprocating piston for displacing the striker, and an axially displaceable guide tube for guiding the piston. A device for holding the striker in a forward position thereof adjacent to the tool holder in an idling condition of the hammer drill is provided in the hammer drill. The device has a guide element fixed in the drill housing for guiding the guide tube. The guide tube has a control opening for venting the air cushion and which remains in open or closed condition dependent on axial position of the guide tube.
Claims13
A power hammer drill, comprising a housing;
- a tool holder located in said housing;
- an air cushion striking mechanism arranged in said housing for driving a tool and including a striker, a reciprocating piston for displacing said striker, and an axially displaceable guide tube for guiding said piston in reciprocating movement thereof and having at least one control opening for venting an air cushion;
- and means for holding the striker in a forward position thereof adjacent to said tool holder in an idling condition of said hammer drill, said holding means comprising a guide element supported in said housing for guiding said guide tube during axial displacement of said guide tube, said guide element being fixed in said housing against axial displacement, said control opening having one of closed and open conditions in accordance with an axial position of said guide tube.
Dependencies are inferred from the claim text.