Variable-speed drill
US3975966A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Dec 11, 1974 |
| Grant date | Aug 24, 1976 |
| Priority date | — |
| Expiry date | Dec 11, 1994 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T74/19274
- WIPO fieldMachine tools
- WIPO sectorMechanical engineering
Abstract
A housing accommodates a motor and a tool shaft which is to be driven by the same. A gear drive is interposed between the motor and the tool shaft and transmits power from the former to the latter. The gear drive has at least two gear sets providing different gear ratios, and an intermediate shaft. An axial safety coupling is associated with each of the gear sets and provided on the intermediate shaft to be rotatable with the same. Each safety coupling includes axially extending projections which are distributed about the axis of rotation of the intermediate shaft and which have circumferentially defined flanks. Each safety coupling has a diameter and a flank inclination at least one of which is accommodated to the torque generated by the gear ratio associated with the safety coupling. A biasing spring urges the projections of the safety couplings into engagement with one another.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.