Sequentially actuated pressure switches having separate resistor elements associated with each

Claim 2

A pressure switch unit, comprising a housing having a chamber therein, a plurality of pressure responsive switches mounted in said chamber for movement between open and closed positions, means connecting said chamber to a supply of pressure fluid thereby to apply the pressure of said fluid to all said switches simultaneously to urge said switches to closed positions, separate resilient means connected to each switch normally to hold the respective switches open, said resilient means for the individual switches being operative to require, respectively, different amounts of pressure to close the separate switches, against the resistances of the resilient means associated with the respective switches, an electrical terminal fastened to said housing to connect to an electrically-operated pressure gauge, and a separate resistor connecting each of the separate switches, respectively, with said terminal, the separate resistors having, respectively, different resistances.

Claim 3

A pressure switch unit as defined in claim 1, including a printed circuit substrate in said housing, each of said resistors being printed on said substrate with one end thereof oPeratively connected directly to said terminal, and with the opposite end thereof connected to one of said switches.

Claim 4

A pressure switch unit as defined in claim 1, wherein said switches comprise a plurality of movable contacts electrically connected by said resilient means to different of said resistors, respectively, and said means for applying said pressure fluid to said switches comprises a plurality of flexible diaphragms mounted in said housing and responsive to predetermined variations in fluid pressure to urge said different switches, respectively, to closed positions, thereby to introduce said resistors separately into circuit with the gauge.

Claim 5

A pressure switch unit for monitoring the fluid of a system comprising a housing having thereon a terminal, a plurality of normally-open switches mounted in said housing and angularly spaced from one another around said terminal, a plurality of resistors in said housing and each connected at one end to said terminal, and connected at their opposite ends through said switches to another terminal, whereby said resistors may be connected selectively between said terminals by the selective closing of said switches, means for connecting said housing to a supply of fluid under pressure, and pressure responsive means interposed between said connecting means and said switches, and operative, when the pressure of said fluid increases from a predetermined low range to a predetermined high range, successively to close said switches and connect said resistors between said terminals.

Claim 6

A pressure switch unit for monitoring the fluid of a system comprising a housing having thereon a terminal, a plurality of normally-open switches mounted in said housing and angularly spaced from one another around said terminal, a plurality of resistors in said housing and each connected at one end to said terminal, and connected at their opposite ends through said switches to another terminal, whereby said resistors may be connected selectively between said terminals by the selective closing of said switches, means for connecting said housing to a supply of fluid under pressure, and pressure responsive means interposed between said connecting means and said switches, and operative, when the pressure of said fluid increases from a predetermined low range to a predetermined high range, successively to close said switches and connect said resistors between said terminals.

Claim 7

A pressure switch unit as defined in claim 4, wherein said pressure responsive means comprises a plurality of flexible diaphragms secured in said housing with one side thereof in communication with said connecting means, each of said switches comprises a metal contact mounted to reciprocate in said housing at the opposite side of one of said diaphragms, a plurality of electrically conductive springs are interposed between said contacts and said opposite ends of said resistors electrically to connect each contact to one of said resistors, and normally to hold said contacts in open positions against said diaphragms, and said diaphragms are operative for different values of pressure of said fluid to urge said contacts to closed positions against said other terminal electrically to connect the respective associated resistors in said circuit through one of said springs.

Claim 8

A pressure switch unit as defined in claim 4, including a printed circuit substrate secured in said housing to said terminal and having said resistors printed thereon, each of said resistors having a different ohmic value, and means operative to resist movement of said switches to their closed positions until said pressure has reached predetermined values which differ for each switch.

Claim 9

A pressure sender switch unit, comprising a housing having an electrical terminal secured thereto, a printed circuit substrate in said housing having a plurality of separate resistances of respectively different values printed thereon, each of said resistances being electrically connected at one end to said terminal, a plurality of separate switches mounted in said housing, equal in number to said resistances, different spring means electrically connecting the opposite ends of said resistances to separate ones of said switches, and acting on one side of each switch normally to hold the associated switch open, the different spring means yielding, respectively, to different pressures to permit the separate switches to close, a flexible diaphragm associated with each switch at the opposite side thereof from the associated spring means, and means for admitting fluid under pressure into said housing against the separate diaphragms simultaneously, whereby the different switches are closed successively at the different pressures required to overcome their respective associated spring means, each Switch, when closed, contacting an electrically conductive portion of said housing to close a circuit from the associated resistance to ground.

Claim 10

A pressure sender switch unit, comprising a housing having an electrical terminal secured thereto, a printed circuit substrate in said housing having a plurality of separate resistances of respectively different values printed thereon, each of said resistances being electrically connected at one end to said terminal, a plurality of separate switches mounted in said housing, equal in number to said resistances, different spring means electrically connecting the opposite ends of said resistances to separate ones of said switches, and acting on one side of each switch normally to hold the associated switch open, the different spring means yielding, respectively, to different pressures to permit the separate switches to close, a flexible diaphragm associated with each switch at the opposite side thereof from the associated spring means, and means for admitting fluid under pressure into said housing against the separate diaphragms simultaneously, whereby the different switches are closed successively at the different pressures required to overcome their respective associated spring means, each Switch, when closed, contacting an electrically conductive portion of said housing to close a circuit from the associated resistance to ground.