Washer fluid low level warning switch

Claim 2

A low level warning switch for use in a windshield washer fluid container comprising a housing having an upper closure and a lower closure, a pair of contacts of magnetic material positioned in said upper closure and spaced from each other, said contacts being adapted to be connected to an electric circuit, a magnet within said housing movable between said upper and lower closures and adapted to electrically bridge said contacts, a shaft formed integrally with said lower closure and extending downwardly therefrom, a float slidably positioned on said shaft and a spacer of magnetic material positioned on said float, said spacer being adapted to abut said lower closure and provide a low reluctance path whereby said magnet is attracted toward said spacer to maintain said contacts open.

Claim 3

A low level warning switch as defined by claim 1 wherein said spacer comprises a steel ring slidably movable on said shaft above said float.

Claim 4

A low level warning switch as defined by claim 1 wherein said magnet is partially encased in a brass casing.

Claim 5

A low level warning switch as defined by claim 1 wherein a clip is positioned on said shaft below said float to limit the downward movement of said float.

Claim 6

A low level responsive switch for a fluid container, comprising in combination: a housing defining a cavity having a roof and a floor, the roof having a pair of spaced electrical contacts and being composed at least in part of material having low magnetic reluctance, an armature disposed in the cavity and including a permanent magnet and means to bridge said contacts when the armature is in lifted position, the armature and cavity having complementary shapes to register said means and said contacts when the armature is lifted, the strength of the magnet and the reluctance of the roof being so related to the mass of the armature as to lift the armature to contact-making position when the armature is free of bottoming force; a float disposEd outside the cavity and within the container to rise and fall with liquid level therein, the float having low reluctance material at its top, the reluctance of the magnetic path thereby formed when the float is against the floor of the cavity being sufficiently low to arrest lifting of the armature and to withdraw the armature from elevated position, the attraction of the float and armature being insufficient to sustain the weight of the float in the absence of fluid support, the float and the container having guide defining conformations effective to confine the float to registered position in relation to the floor.

Claim 7

A low level responsive switch for a fluid container, comprising in combination: a housing defining a cavity having a roof and a floor, the roof having a pair of spaced electrical contacts and being composed at least in part of material having low magnetic reluctance, an armature disposed in the cavity and including a permanent magnet and means to bridge said contacts when the armature is in lifted position, the armature and cavity having complementary shapes to register said means and said contacts when the armature is lifted, the strength of the magnet and the reluctance of the roof being so related to the mass of the armature as to lift the armature to contact-making position when the armature is free of bottoming force; a float disposEd outside the cavity and within the container to rise and fall with liquid level therein, the float having low reluctance material at its top, the reluctance of the magnetic path thereby formed when the float is against the floor of the cavity being sufficiently low to arrest lifting of the armature and to withdraw the armature from elevated position, the attraction of the float and armature being insufficient to sustain the weight of the float in the absence of fluid support, the float and the container having guide defining conformations effective to confine the float to registered position in relation to the floor.