Power tool, in particular a hand-held compressed air screw driver
US4320806A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 20, 1979 |
| Grant date | Mar 23, 1982 |
| Priority date | — |
| Expiry date | Apr 20, 1999 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB25B23/145
- WIPO fieldMachine tools
- WIPO sectorMechanical engineering
Abstract
A pneumatic screwdriver or nutsetter includes a manually actuated electrical switch and a solenoid operated motive air shutoff valve which includes a spring biased reset element for moving the shutoff valve closure element from a valve closed position to a valve open position prior to introduction of compressed air to the tool motor. The reset element is retracted away from the closure element by pressure air on startup of a tool operating cycle. The closure element is released upon deenergization of the solenoid at a predetermined signal to close the shutoff valve. In an alternate embodiment the switch is replaced by a pneumatic valve and the reset element is pressure air biased to move the shutoff element from the shutoff valve closed position to the open position.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.