Liquid level control system and switch assembly therefor

Claim 2

A switch actuating assembly including, in combination, housing means, switch means supported by said housing means and including at least one pair of magnetizable conducting reeds projecting toward each other in cantilever fashion with overlapping normally spaced adjacent ends, magnet means having spaced magnetic pole faces establishing a magnetic field therebetween, said magnet means being movable between a first position wherein at least one of said reeds is outside the influence of said magnetic field and a second position wherein said reeds are each influenced by a separate pole of said magnet means so that said reeds are attracted to each other to close at their said adjacent ends, and means disposed at said first and second positions of travel of said magnet means for effecting snap-action movement of said magnet means as said magnet means approaches its said first and second positions, said means for effecting snap-action movement of said magnet means comprising a metallic pole piece disposed at each of the opposite ends of travel of said magnet means, said pole pieces further serving to effect latching of said magnet means therewith until a predetermined force is applied to said magnet means to effect release of said magnet means from the associated pole piece.

Claim 3

A switch actuating assembly as defined in claim 1 wherein said metallic pole pieces are made of stainless steel and have negligible residual magnetism after release from said magnet means.

Claim 4

A switch actuating assembly including, in combination, housing means, switch means supported by said housing means and including at least one pair of magnetizable conducting reeds projecting toward each other in cantilever fashion with overlapping normally spaced adjacent ends, magnet means having spaced magnetic pole faces establishing a magnetic field therebetween, said magnet means being movable between a first position wherein at least one of said reeds is outside the influence of said magnetic field and a second position wherein said reeds are each influenced by a separate pole of said magnet means so that said reeds are attracted to each other to close at their said adjacent ends, and means disposed at said first and second positions of travel of said magnet means for effecting snap-action movement of said magnet means as said magnet means approaches its said first and second positions, and a printed circuit board supported by said housing means, said reed switch means being secured to said board in predetermined relation thereon so that assembly of said printed circuit board and said housing means establishes said reed switch means in predetermined relation to said magnet means.

Claim 5

A switch actuating assembly including, in combination, housing means, switch means supported by said housing means and including at least one pair of magnetizable conducting reeds projecting toward each other in cantilever fashion with overlapping normally spaced adjacent ends, magnet means having spaced magnetic pole faces establishing a magnetic field therebetween, said magnet means being movable between a first position wherein at least one of said reeds is outside the influence of said magnetic field and a second position wherein said reeds are each influenced by a separate pole of said magnet means so that said reeds are attracted to each other to close at their said adjacent ends, and means disposed at said first and second positions of travel of said magnet means for effecting snap-action movement of said magnet means as said magnet means approaches its said first and second positions, and a printed circuit board supported by said housing means, said reed switch means being secured to said board in predetermined relation thereon so that assembly of said printed circuit board and said housing means establishes said reed switch means in predetermined relation to said magnet means.

Claim 6

A switch actuating assembly as defIned in claim 3 including an encapsulating material disposed within said housing means to seal said reed switch means and said printed circuit board for immersion in a liquid.

Claim 7

A switch actuating assembly as defined in claim 4 wherein said magnet means is adapted to be moved by a force acting externally of said housing means.

Claim 8

In a liquid tank or the like adapted to hold a liquid the level of which may increase by the introduction of liquid into the tank, the tank having pump means associated therewith to effect selective withdrawal of liquid from the tank; the combination therewith of switch means adapted to selectively energize the pump means, switch actuating means adapted to establish a first switch condition for said switch means to energize the pump means when the liquid level within the tank reaches a predetermined upper level and maintain said first switch condition until the level of the liquid falls to a predetermined lower level whereupon a second switch condition is established to de-energize the pump means, said switch means including a pair of elongated magnetizable contact elements projecting toward each other in cantilever fashion and having overlapping adjacent ends normally spaced to establish said first switch condition, and said switch actuating means including magnet means supported by said housing means for movement between a first position wherein the magnet is ineffective to close said switch contacts and a second position wherein the magnet is effective to close said switch contacts, said switch actuating means further including float means interconnected to said magnet means and movable in response to a change in liquid level within the tank to selectively move said magnet means, and means supported by said housing for cooperation with said magnet means to effect snap-action movement of said magnet means toward its said first and second positions after being moved to the general proximity of its said first or second positions by said float means in response to changes in liquid level within the tank.

Claim 9

In a liquid tank or the like adapted to hold a liquid the level of which may increase by the introduction of liquid into the tank, the tank having pump means associated therewith to effect selective withdrawal of liquid from the tank; the combination therewith of switch means adapted to selectively energize the pump means, switch actuating means adapted to establish a first switch condition for said switch means to energize the pump means when the liquid level within the tank reaches a predetermined upper level and maintain said first switch condition until the level of the liquid falls to a predetermined lower level whereupon a second switch condition is established to de-energize the pump means, said switch means including a pair of elongated magnetizable contact elements projecting toward each other in cantilever fashion and having overlapping adjacent ends normally spaced to establish said first switch condition, and said switch actuating means including magnet means supported by said housing means for movement between a first position wherein the magnet is ineffective to close said switch contacts and a second position wherein the magnet is effective to close said switch contacts, said switch actuating means further including float means interconnected to said magnet means and movable in response to a change in liquid level within the tank to selectively move said magnet means, and means supported by said housing for cooperation with said magnet means to effect snap-action movement of said magnet means toward its said first and second positions after being moved to the general proximity of its said first or second positions by said float means in response to changes in liquid level within the tank.

Claim 10

The combination of claim 6 wherein said means to effect snap-action movement of said magnet means comprise metallic pole pieces which are disposed at opposite ends of the travel stroke of said magnet means and effect latching of said magnet means in its said first and second positions after movement thereto by said float means until a predetermined force is applied to said magnet means in a direction to release said magnet means from the associated pole piece.

Claim 11

The combination as defined in claim 6 wherein said switch actuating means includes a control rod secured to said magnet means, said float means being slidably supported on said rod for movement longitudinally therealong, and stop means adjustable along the length of said rod to limit the extent of sliding movement of said float whereby said float is slidable along said rod a predetermined distance without effecting movement of said rod in response to a change in liquid level in the tank.

Claim 12

The combination as defined in claim 6 wherein said switch actuating means includes a control rod secured to said magnet means, said housing means having bearing cap means thereon providing lateral support for said rod along the length thereof spaced from said magnet means.

Claim 13

The combination as defined in claim 6 wherein said housing means includes an encapsulating material which serves to hermetically seal said switch means.

Claim 14

The combination as defined in claim 6 wherein said magnet means comprises an annular magnet supported by said housing means for movement in a direction along the axis of said annular magnet, said pole pieces having annular configurations and being disposed in axial alignment with said annular magnet.