Power hand tool
AssigneeRobert Bosch GmbH
InventorKlaus Voss
Life of this patent
Estimating the term…
Abstract
To prevent accidents due to high torque of hand tools, such as drills, and the like, which, when the tool bit stalls, may tend to twist the tool handle from the user's hand, a torque measuring element is located on the tool body at the junction of the tool body and the handle and connected to the power supply of the tool to discontinue or interrupt power supply thereto upon sensing of deformation between the tool body and the handle thereof due to excessive strain on said junction; preferably, the handle is joined to the tool body by a section of material of reduced cross-sectional size to accentuate any deformation between the tool handle and the body.
Claims16
Power hand tool having a tool body (2), a drive motor (8, 38, 48) secured in the body, and a holding handle (4, 24) for manually holding the tool, the holding handle being joined to the tool body, said tool comprising
- a torque sensing element (7, 27, 37, 57) located at the junction of the tool body and the handle and comprising a strain measuring transducer (7, 27, 37, 57) providing an electrical output signal, said strain measuring transducer being positioned on the tool adjacent the junction of the tool body and the holding handle to be responsive to deformation of the handle (4, 24) with respect to the tool body (2, 22);
- and means connecting said strain measuring transducer and the motor to control the motor operation as a function of the output signal and thus of the torque between the tool body and the holding handle.
Dependencies are inferred from the claim text.