Power screwdriver
First Claim
Patent Images
1. A power screwdriver comprising:
- a drive;
a tool drive shaft for driving a tool;
a clutch, releasing when a certain preset torque is reached, having an input side being coupled to said drive and having an output side being coupled to said tool drive shaft;
a sensor being coupled to said clutch for sensing a release of said clutch;
an angle sensor for sensing a rotation angle of said tool drive shaft;
brake means for braking said drive after release of said clutch; and
an electronic control for controlling said drive, said electronic control being coupled to said sensor for deactivating said drive when said clutch releases, and wherein said electronic control is coupled to said angle sensor for switching on said drive again upon reaching a first rotation angle after release of said clutch and for switching off said drive again upon reaching a second rotation angle after release of said clutch.
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Abstract
A power screwdriver is disclosed having a drive which is coupled via a clutch, disengaging as a function of torque, to a tool drive shaft for driving a tool. The screwdriver comprises an electronic control unit for controlling the drive, and a sensor which is coupled to the electronic control unit in order to switch off the drive when the clutch responds. The electronic control unit is designed for activating the drive with a certain output, preferably with a reduced output, for a limited time after switch-off.
58 Citations
19 Claims
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1. A power screwdriver comprising:
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a drive; a tool drive shaft for driving a tool; a clutch, releasing when a certain preset torque is reached, having an input side being coupled to said drive and having an output side being coupled to said tool drive shaft; a sensor being coupled to said clutch for sensing a release of said clutch; an angle sensor for sensing a rotation angle of said tool drive shaft;
brake means for braking said drive after release of said clutch; andan electronic control for controlling said drive, said electronic control being coupled to said sensor for deactivating said drive when said clutch releases, and wherein said electronic control is coupled to said angle sensor for switching on said drive again upon reaching a first rotation angle after release of said clutch and for switching off said drive again upon reaching a second rotation angle after release of said clutch. - View Dependent Claims (2, 3)
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4. A power screwdriver comprising:
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a drive; a tool drive shaft for driving a tool; a clutch, releasing when a certain preset torque is reached, having an input side being coupled to said drive and having an output side being coupled to said tool drive shaft; a sensor being coupled to said clutch for sensing a release of said clutch; and an electronic control for controlling said drive, said electronic control being coupled to said sensor for deactivating said drive when said clutch releases, wherein said electronic control is configured for reactivating said drive with a certain output for a limited time after deactivation of said drive. - View Dependent Claims (5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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16. A method of controlling a power screwdriver for tightening a screw connection with a certain tightening torque, comprising the following steps:
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providing a clutch between a drive and a tool drive shaft for driving a tool, said clutch being releasable as a function of torque; driving said tool drive shaft via said clutch; monitoring said clutch for release; switching off said drive when said clutch releases; braking said drive; switching on said drive again for subsequently driving said clutch for a limited time period; and switching off said drive again according to a predetermined switch-off criterion. - View Dependent Claims (17, 18, 19)
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Specification