Stroke energy limited motor-driven screwdriver
US4056762A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Feb 27, 1976 |
| Grant date | Nov 1, 1977 |
| Priority date | — |
| Expiry date | Feb 27, 1996 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB25B23/1475
- WIPO fieldMachine tools
- WIPO sectorMechanical engineering
Abstract
An energy limiting circuit for the operating stroke of a motor-driven screwdriver energized by alternating current is activated in response to a pulse of current amplitude, which may be the starting current of the motor or the first of a series of current amplitude pulses characteristic of screw tightening impacts produced by an impact-type screwdriver. The energy limiting circuit in a simple case is a timing circuit. For operation with strict reference to the impacting energy, the energy limiting circuit is a pulse counter. Adjustment of the timing or of the pulse counting is provided for setting the tool to the conditions of a particular repetitive task.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.