Precision-fastening handheld cordless power tools
US9281770B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jan 11, 2013 |
| Grant date | Mar 8, 2016 |
| Priority date | — |
| Expiry date | Jan 20, 2033 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB25F5/00
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
Cordless power tools include a pistol housing having an upper portion that merges into a downwardly extending handle, a DC motor residing in the upper portion of the housing, the DC motor having a rotor that drives an output shaft; a torque transducer on board the tool in communication with the output shaft; and a dynamic motor control circuit residing in the housing in communication with the motor and torque transducer. The dynamic motor control circuit includes a Kelvin resistor in communication with the motor for measuring motor current and digital hall switches in communication with the motor for measuring motor speed. The motor current can vary by at least 100 A during operation.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.