Electrical safety switch
AssigneeEaton Corporation
InventorsJean Claude Buffet, Lionel Raut
Life of this patent
Estimating the term…
Abstract
For protecting the pump of a carpet cleaner, the cut-out terminals 16, 15 are commanded by the pressure of fluid in passage 11, 12, 13 which communicates with volume 22 having as an upper wall a flexible diaphragm 24. A fluid tight and electrically insulating housing 9 has a fixed boss portion 19 which is surrounded by a mobile annular permanent magnet 25 carried by diaphragm 24 and which guides a central mobile permanent magnet 20 which drives a mobile contact 18 up or down, closing or opening terminals 15, 16. High pressure at 11 drives diaphragm 24 and magnet 25 upwards, which attracts magnet 20 upwards, and connects terminals 15, 16 via mobile contact 18.
Claims8
Electrical switch, actuated by the pressure of a liquid or gaseous fluid, characterized in that it features a body with a fluid passage;
- a chamber communicating (at point) with said fluid passage;
- a moving and/or flexible part inside the chamber, linked to an annular magnet;
- an electrically insulated, sealed inner wall surrounded by annular magnet, which houses and guides an axially displaced central magnet, mechanically linked at point to a mobile contact piece, such as a contact tongue, which cooperates with at least one fixed electrical terminal to close and open an electrical circuit, depending on the position of the central magnet, which is magnetically coupled with the coaxial annular magnet, the position of said annular magnet being determined by pressure of the fluid which enters the aforementioned chamber.
A method of operating an electrical switch in response to sensed changes in fluid pressure:
- (a) forming a cavity having a relatively thin wall portion in a housing and disposing a switch in the cavity;
- (b) disposing a first permanent magnet in said cavity adjacent said wall portion and connecting said magnet to a moveable member of said switch;
- (c) forming a pressure chamber in the housing having said thin wall portion forming a part thereof and disposing a pressure responsive moveable member in said chamber;
- (d) disposing a second permanent magnet for movement with said pressure responsive member and positioning said annular magnet adjacent said thin wall portion on the side thereof opposite said first magnet;
- (e) forming a fluid passage in said housing having an inlet, outlet and forming a venturi throat in said passage between the inlet and outlet;
- (f) tapping said venturi and connecting the tap to said pressure chamber;
- and,
- (g) flowing fluid through the venturi throat and moving said pressure responsive member and second magnet and magnetically effecting movement of said first magnet through said wall portion in response to the pressure in said venturi tap.
Dependencies are inferred from the claim text.