Electro-mechanical liquid level sensor

Claim 2

A liquid level indicator comprising: (a) a container for a liquid; (b) a switch housing disposed in the container at a level below normal liquid level height, the interior of said switch housing being liquidly isolated from said container and said switch housing including: (i) a pair of spaced contacts; (ii) an electrically conductive member operable between a first position wherein it is spaced from the contacts and a second position wherein it engages the contacts and closed a circuit; (iii) a magnet affixed to said electrically conductive member; (c) a float assembly adapted for floating at the top of liquid in said container, said float assembly including a magnetically attractable material; (d) said magnetic being attracted to the magnetically attractable material when the liquid level reaches a predetermined level whereby the electrically conductive member is urged into engagement with the pair of contacts; and (e) the force of attraction between the magnet and the magnetically attractable material being greater than the buoyant force of the float assembly in the liquid.

Claim 3

The apparatus of claim 1 wherein the float assembly and magnetically attractable material are of toroidal shape.

Claim 4

The apparatus of claim 1 wherein the float assembly further comprises a spacing rim about its periphery for maintaining the magnetically attractable material in a predetermined altitude in the container.

Claim 5

The apparatus of claim 1 wherein the switch assembly is isolated from the liquid by a non-magnetically attractable shroud.

Claim 6

The apparatus of claim 4 wherein the shroud is spaced from the magnet a distance greater than the electrically conductive member is spaced from the contacts in its first position.

Claim 7

A liquid level indicator comprising: (a) a container for a liquid said container having a sidewall; (b) an electrical circuit; (c) a switching assembly for said electrical circuit rigidly fixed in the sidewall of the container at a level below normal liquid level height, said switching assembly comprising: (i) a pair of spaced pivot members, each of said pivot members having an electrical contact portion in electrical communication with said electrical circuit; (ii) a pendulum assembly mounted on said pivot members, said pendulum assembly being free to pivot around a horizontal axis on said pivot members, said pendulum assembly including a contact member moveable between a first position in which it is electrically isolated from at least one of said contact portions and a second position in which it is in electrical communication with each said electrical contact portion, said contact member having first magnetic means attached thereto; (d) a float assembly for floating at the top of the liquid, said float assembly including second magnetic means; (e) said second magnetic means being attracted to the first magnetic means when the float assembly reaches a predetermined level, whereby the contact member moves from its first position to its second position.

Claim 8

A liquid level indicator comprising: (a) a container for a liquid said container having a sidewall; (b) an electrical circuit; (c) a switching assembly for said electrical circuit rigidly fixed in the sidewall of the container at a level below normal liquid level height, said switching assembly comprising: (i) a pair of spaced pivot members, each of said pivot members having an electrical contact portion in electrical communication with said electrical circuit; (ii) a pendulum assembly mounted on said pivot members, said pendulum assembly being free to pivot around a horizontal axis on said pivot members, said pendulum assembly including a contact member moveable between a first position in which it is electrically isolated from at least one of said contact portions and a second position in which it is in electrical communication with each said electrical contact portion, said contact member having first magnetic means attached thereto; (d) a float assembly for floating at the top of the liquid, said float assembly including second magnetic means; (e) said second magnetic means being attracted to the first magnetic means when the float assembly reaches a predetermined level, whereby the contact member moves from its first position to its second position.

Claim 9

The apparatus of claim 6 wherein the float assembly and magnetically attractable material are of toroidal shape.

Claim 10

The apparatus of claim 6 wherein the float assembly further comprises a spacing rim about its periphery for maintaining the magnetically attractable material in a predetermined altitude in the container.

Claim 11

A switching assembly for a liquid level sensor, said switching assembly including: (a) a pair of spaced pivot members, each of said pivot members having an electrical contact portion associated therewith; (b) a pendulum assembly mounted on said pivot members, said pendulum assembly being free to pivot around a horizontal axis on said pivot members, said pendulum assembly including a contact member moveable between a first position in which it is electrically isolated from at least one of said contact portions and a second position in which it is in electrical communication with each said electrical contact portion, said contact member having magnetic means attached thereto; (c) said contact member being normally in its first position but moveable to its second position in response to magnetic attraction of said magnetic means.

Claim 12

A switching assembly for a liquid level sensor, said switching assembly including: (a) a pair of spaced pivot members, each of said pivot members having an electrical contact portion associated therewith; (b) a pendulum assembly mounted on said pivot members, said pendulum assembly being free to pivot around a horizontal axis on said pivot members, said pendulum assembly including a contact member moveable between a first position in which it is electrically isolated from at least one of said contact portions and a second position in which it is in electrical communication with each said electrical contact portion, said contact member having magnetic means attached thereto; (c) said contact member being normally in its first position but moveable to its second position in response to magnetic attraction of said magnetic means.