Control device for boring machine
US6072675A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 3, 1998 |
| Grant date | Jun 6, 2000 |
| Priority date | — |
| Expiry date | Nov 3, 2018 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02H7/0859
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
The operation of an electric drill is inhibited when it is interrupted by an abrupt fault such as power failure and then the fault is recovered, or when the coil of an electromagnet has a trouble such as disconnection. After the fault is eliminated with a power switch 50 remaining closed for energizing the electromagnet and the electric drill, a photocoupler 38 turns on a thyristor 31 to disable the conduction of a transistor 35. As the result, a drill motor 16 will not start before the magnetization of the electromagnet. The trouble in the coil 27 is detected by a potential examining circuit 30 measuring a potential difference across a resistor 31. The detection of the trouble causes the thyristor 31 to interrupt the conduction of the transistor 35. Accordingly, the electric drill will not start again unless it is securely anchored by the electromagnet.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.