Dial speed control for hand-held power tool
US5561734A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 13, 1992 |
| Grant date | Oct 1, 1996 |
| Priority date | — |
| Expiry date | Aug 13, 2012 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH05K1/18
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
An electric tool including a variable speed switch assembly including a potentiometer having a central rotatable member defining a bore with a noncircular cross section and a molded plastic speed control wheel housing the potentiometer. The speed control wheel includes a central post with a cross section corresponding to the cross section of the central potentiometer bore such that the central post can be housed in the central bore in only one relative position with respect to the central rotatable member. The variable speed switch assembly also includes a switch cover having projections which snap into designated holes provided in a circuit board such that the switch cover and the circuit cannot be incorrectly assembled. The switch cover includes a stop member that extends into a semi-circular recess in the speed control wheel to provide mechanical stops so that rotational movement of the speed control wheel corresponds with the range of the potentiometer. The variable speed switch assembly also incorporates a detent arrangement integrated into the switch cover and the speed control wheel and including a resilient finger, the end of which is received in a series of detent grooves …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.