Computer controlled automatic shift drill
US4854786A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 26, 1988 |
| Grant date | Aug 8, 1989 |
| Priority date | — |
| Expiry date | May 26, 2008 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T409/30728
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
The trust exerted on a drill bit is sensed and employed to determine the speed at which the bit is driven. A controller for the drill compares the thrust to a predetermined threshold value and in response to the comparison emits a control signal which shifts a transmission in the drill into high or low speed. After each shift, a number of thrust samples are taken in order to compute an average thrust for different strata of the material being drilled. At the completion of drilling each hole, the average thrusts for the hole are used to recalibrate the shift threshold value. In this manner, the shift threshold is adjusted to compensate for drill bit wear. The sensed thrust is also compared to a bit reject threshold value to determine when the bit is too dull for proper drilling.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.