Handheld power tool
US11027389B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jun 22, 2017 |
| Grant date | Jun 8, 2021 |
| Priority date | — |
| Expiry date | Mar 11, 2038 |
Classification
- Technology area (CPC F)Mechanical Engineering; Lighting; Heating
- CPC primaryF16D2121/22
- WIPO fieldMachine tools
- WIPO sectorMechanical engineering
Abstract
A handheld power tool includes a tool holder for holding a tool, an electric motor, a shaft connecting the tool holder and the electric motor, and a protective device for stopping the tool holder in an uncontrolled situation. The protective device includes a sensor for detecting the uncontrolled situation, a switchable current source and a normally closing magnetic brake. The switchable current source outputs a first current not equal to zero in response to signals of the sensor if an uncontrolled situation is not detected; the current source does not output a current or outputs a second current different from the first current if an uncontrolled situation is detected. The normally closing magnetic brake engages on the shaft and does not apply a torque to the shaft when energized by the first current. The normally closing magnetic brake applies a torque counteracting the rotational movement of the shaft when not energized or when energized by the second current.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.