Switching device

Claim 1

Means for selectively disengaging an air conditioner compressor and removing the drag and load imposed thereby on a vehicle engine that is operative thereof, and comprising: a vacuum responsive switching device, means for electrically connecting said switching device in circuit between the magnetic clutch for an air conditioner compressor and its electrical power source, means for connecting said switching device to a source of intake manifold vacuum pressure for sensing the changing conditions thereof under varying engine conditions, and means for selectively and readily adjusting the sensitivity and response of said switching device to different load and power demands made by said engine for varying the extent and duration of the disengagement of said compressor from said engine for comfort and economy control, having the switching device and its adjustable means provided within the passenger compartment of the vehicle driven by said engine and serviced by said air conditioner, for each of access thereto and for adjustment and selective settings in accord with road conditions as and when encountered, said switching device including a diaphragm member having one side thereof responsive to engine intake manifold pressure, said readily adjustable means including spring means connected to said diaphragm member and for counteracting the effects of said manifold pressure, and threaded means for varying the strength and effects of said spring means, said spring means including a tension spring connected between said diaphragm and said threaded means on the opposite side of said diaphragm from that which is responsive to said manifold pressure, a check valve provided in said switching device for closing and shutting off vacuum pressure to said switching device, said check valve being biased to a closed position and being responsive to an overriding decrease in vacuum pressure by opening, and means provided for bleed-by around said check valve when in a closed position.