Semi-Active Anti-Vibration Systems for Handheld Electrical Power Tools
AssigneesRobert Bosch GmbH, Robert Bosch Tool Corporation
InventorStephen C. Oberheim
Life of this patent
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Abstract
An improved vibration dampening system has been developed for handheld electrical power tools. The vibration dampening system includes a material that a controller selectively activates with an electrical current to increase the rigidity of the material and dampen random vibrations detected by the controller. The material is positioned between a foot member that helps support the tool against a work piece and both hand grips for the tool. Thus, the vibration dampening system reduces the impact of random vibrations on both hands of an operator.
Claims29
A handheld electrical power tool comprising:
- a housing forming a first grip configured to engage one hand of an operator and a second grip configured to engage another hand of the operator;
- an electrical motor located in the housing that is configured to drive a tool;
- a foot member outside the housing that is configured to engage a work piece and support the housing and the electrical motor with reference to the work piece;
- a movable member operatively connected to the housing and to the foot member, the movable member being configured to move from a first position to a second position in response to a movement of the foot member toward the housing and to move from the second position to the first position in response to a movement of the foot member away from the housing;
- a vibrational dampener positioned proximate to the foot member and operatively connected to the movable member, the vibrational dampener including a variable rheological materia;
- and
- a controller located in the housing and operatively connected to the vibrational dampener, the controller being configured to selectively activate an electric current to adjust a mechanical resistance of the variable rheological material to dampen vibrational forces transmitted to the first grip and the second grip during operation of the electrical motor.
A method of dampening vibration in a handheld electrical power tool comprising:
- driving a tool with an electrical motor located in a housing of the handheld electrical power tool, the housing having a first hand grip and a second hand grip;
- moving a movable member mechanically connected between the housing and a foot member configured to support the handheld electrical power tool with reference to a work piece, the foot member being between the work piece and the first and the second hand grips and the movable member moving from a first position to a second position in response to the foot member moving toward the housing and from the second position to the first position in response to the foot member moving away from the housing during the driving of the tool with the electrical motor;
- and
- selectively activating an electric current to adjust a mechanical resistance of a variable rheological material in a vibrational dampener located proximate to the foot member to dampen the vibrational force transmitted between the foot member and the housing.
Dependencies are inferred from the claim text.