Portable actuator for inductive load
US4697221A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Sep 29, 1986 |
| Grant date | Sep 29, 1987 |
| Priority date | — |
| Expiry date | Sep 29, 2006 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01H47/043
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A battery operated, portable actuator for an inductive load such as an electromagnetically actuatable photographic shutter includes an initiating capacitor for initiating acutation of the load, and a continuing holding circuit portion for continuing energizing the load after discharge of the initiating capacitor. The capacitor is connected to be charged by the output of a voltage multiplying rectifier which is alternately turned ON and OFF according to the instantaneous voltage across the capacitor, being turned ON when the voltage is low, and OFF when the voltage is high. The continuing circuit portion is arranged to feed time-spaced current pulses to the load, and a diode is connected across the load so that its own inductive nature holds it energized during the intervals between the pulses. The duration of the energizing current pulses is increased in response to fall-off of the battery output voltage. All of these features combine to enhance the effective life of the battery, minimizing current drain on it, while simultaneously ensuring reliable operation of the load.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.