Portable drilling device
US7936142B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Dec 13, 2006 |
| Grant date | May 3, 2011 |
| Priority date | — |
| Expiry date | Dec 28, 2027 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T408/14
- WIPO fieldMachine tools
- WIPO sectorMechanical engineering
Abstract
A drilling device prevents recurrence of an overload condition after occurrence of the overload condition, thereby improving operability and safety in the drilling device. A motor for rotating a drill is connected to an AC power source through a motor control unit, a current detector, and a power switch. A magnet is also connected to the AC power source through the power switch and a full-wave rectifier. The motor control unit rotationally drives the motor on the basis of a signal sent from a main control unit according to a state in which a motor start switch is on. The main control unit controls the motor control unit to gradually reduce a supply voltage to the motor when the motor becomes overloaded, to gradually increase the voltage to the normal power supply condition when the overload condition is vanished, and to stop power supply to the motor if the overload condition continues for a predetermined period.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.