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:
Apr. 14, 1981
Filed:
May. 02, 1979
Stephen P Johnston, Detroit Lakes, MN (US);
S. J. Electro Systems, Inc., Detroit Lakes, MN (US);
Abstract
A self-contained float switch for use in conjunction with water pumps and the like. The float switch operates to actuate and de-actuate such a pump at particular depths of water (L.sub.1) and (L.sub.2) which define an adjustable pumping range (R). In one embodiment the float switch consists of a cylindrical water-tight float (24) having an electrical cable (26) coming out of one end and terminating at a piggy-back plug (29) for insertion between a power output (20) and electric pump plug (18). The float contains six mercury switches (70-80) disposed obliquely to the axis of the float and equally spaced around the axis. Further circuitry including a relay (48) is provided to switch the heavier current load of the pump (12) in response to the electrical state of the mercury switches. A further preferred embodiment of the float switch employs a double float system having an upper float (174) and lower float (176), each containing a single mercury switch (220 and 210 respectively) contained within the floats along the longitudinal central axis of the cylinder. The upper float (174) controls the maximum water level (L.sub.1) and the lower float (176) controls the minimum water level (L.sub.2).