Automatic control for an adjustable member
US4180087A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 21, 1977 |
| Grant date | Dec 25, 1979 |
| Priority date | — |
| Expiry date | Jul 21, 1997 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T137/86389
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
A switching arrangement for the control of an adjustable member such as a valve includes a light sensitive switch. Detection of a particular light value enables a frequency divider to transmit an opening pulse to a valve control circuit a predetermined delay period after the detection of such light value. The frequency of an output signal of a pulse generator is varied in response to the opening pulse and the frequency divider transmits a closing pulse to the control circuit after a second predetermined time period of different duration from the delay period. In one disclosed embodiment, control of the frequency divider is responsive to moisture content of soil as well as ambient light level for application in automatic sprinkler systems.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.