1. Field of the Invention
This invention relates to an electric switch mechanism and in particular to a multi-function switch mechanism which is responsive to a single variable singal, e.g. a pressure signal.
2. Description of the Prior Art
Pressure signal operated switches are well known. It is also well known to use a plurality of pressure switches in combination, arranged to open or close electrical circuits in response to different pressure level signals from a single source of pressure. However, the use of multiple switches requires the availability of a like number of suitable mounting locations for the switches, multiple taps into the pressure system, and multiple conduits leading from the tap points to the switches. In some installations there are fewer suitable locations for pressure switches and/or tap-in points than there are functions to be controlled by a pressure signal. An object of the present invention is to provide a single switch mechanism, requiring only a single tap-in point, which is adapted to perform plural switching functions in response to its receipt of differing pressure level signals.
Examples of known switches and switch systems which have become a part of the patent literature are shown by the following U.S. Pat. Nos. 2,985,732, granted May 23, 1961 to Ian C. Russell; 3,043,929, granted July 10, 1962, to George C. Guthrie; 3,393,612, granted July 23, 1968, to Joseph E. Gorens and Walter E. Levine; 3,109,908, granted Nov. 5, 1963, to Bertil H. Clason; 3,432,633, granted Mar. 11, 1969, to Gustave A. Sherb; 3,444,341, granted May 19, 1969, to Perceptimus J. Mighton 3,501,959, granted Mar. 24, 1970 to Sherman E. Womack; 3,516,279, granted June 23, 1970 to Robert J. Maziarka; 3,657,501, granted Apr. 18, 1972, to Harold R. Hoyt; 3,735,071, granted May 22, 1973, to George R. Burnett and Gussie E. Burnett; 3,786,210, granted Jan. 15, 1974, to Peter M. Byam; 3,898,405, granted Aug. 5, 1975, to Ernesto Juan Weber and 3,911,238, granted Oct. 7, 1975, to Noel A. Otto and Roger G. Riefler. These patents should be studied when evaluating the present invention and putting it into proper perspective relative to the prior art.