The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Aug. 24, 1993
Filed:
Jan. 09, 1991
John T Thorngren, Dallas, TX (US);
Texand Corporation, Lake Dallas, TX (US);
Abstract
A control switch for controlling the operation of an overhead irrigation system based upon the moisture level of the ground in an area to be irrigated. The control switch includes first and second moisture detection probes positioned at first and second underground locations in the area to be irrigated, which, upon detection that the soil is dry, place a positive conductive charge on the switch, thereby turning on the irrigation equipment. Upon detection that the soil is wet, the probes remove the conductive charge, thereby turning off the irrigation equipment. The control switch provides varying degrees of sensitivity to soil moisture, and varying time delays in turning the switch on when the soil is dry, and in turning the switch off when the soil is wet. A pulsing current protection circuit permits a positive DC signal taken from an AC triac to turn on the triac when both the AC and DC portions of the control switch share a common ground.