Timer circuit-automotive compressor

Claim 2

In an automobile air conditioning system including a refrigerant compressor, a compressor protector comprising: an electromagnetic clutch for interconnecting the automobile engine and said compressor for rotation together when said clutch is energized; circuit means including an electric power source and a fuse for energizing said electromagnetic clutch; compressor protector means for producing a sufficiently large current through said fuse to open it and to deenergize said electromagnetic clutch when the refrigerant charge in said air conditioning system decreases below a level necessary for compressor cooling and lubricating; said compressor protector means including a thermally biased relay which normally holds open a pair of contacts connected between said fuse and ground; said relay having two resistance heaters in circuit with said electric power source and which are normally energized simultaneously to maintain said contact pair open; switch means responsive to the refrigerant temperature and pressure in circuit with said resistance heaters to deenergize one of said resistance heaters when the refrigerant charge level is insufficient for cooling whereby the other of said resistance heaters causes the contact pair to close and pass sufficient current through said fuse to open it and deenergize said compressor.

Claim 3

In an automobile air conditioning system including a refrigerant compressor, a compressor protector comprising: an electromagnetic clutch for interconnecting the automobile engine and said compressor for rotation together when said clutch is energized; circuit means including an electric power source and a fuse for energizing said electromagnetic clutch; compressor protector means for producing a sufficiently large current through said fuse to open it and to deenergize said electro-magnetic clutch when the refrigerant charge in said air conditioning system decreases below a level necessary for compressor cooling and lubricating; said compressor protector means including a thermally biased relay having two cantilever mounted bimetal arms which are connected at their free ends by a heat insulated link to force said arms to move together with changes of temperature; a resistance wire heater wrapped around each bimetal arm in series connection with each other and with said fuse and said power source; said relay also including a pair of contacts connected between said fuse and ground and adapted when closed to cause sufficient current to flow through said fuse to open it and deenergize said electromagnetic clutch; one of said resistance heaters producing a closing movement of said interconnected arms to close said contact pair when energized separately; the other of said resistance heaters producing an opening movement of said interconnected arms to open said contact pair when energized; switch means in circuit with said resistance heaters responsive to the refrigerant temperature and pressure to deenergize said other resistance heater when the refrigerant charge level is insufficient for cooling leaving only said one resistance heater energized whereby the interconnected bimetal arms are moved into a closed operative position to close said contact pair to cause a relatively large current to pass through said fuse and to open it for deenergizing said compressor.

Claim 4

In an automobile air conditioning system including a refrigerant compressor, a compressor protector comprising: an electromagnetic clutch for interconnecting the automobile engine and said compressor for rotation together when said clutch is energized; circuit means including an electric power source and a fuse for energizing said electromagnetic clutch; compressor protector means for producing a sufficiently large current through said fuse to open it and to deenergize said electro-magnetic clutch when the refrigerant charge in said air conditioning system decreases below a level necessary for compressor cooling and lubricating; said compressor protector means including a thermally biased relay having two cantilever mounted bimetal arms which are connected at their free ends by a heat insulated link to force said arms to move together with changes of temperature; a resistance wire heater wrapped around each bimetal arm in series connection with each other and with said fuse and said power source; said relay also including a pair of contacts connected between said fuse and ground and adapted when closed to cause sufficient current to flow through said fuse to open it and deenergize said electromagnetic clutch; one of said resistance heaters producing a closing movement of said interconnected arms to close said contact pair when energized separately; the other of said resistance heaters producing an opening movement of said interconnected arms to open said contact pair when energized; switch means in circuit with said resistance heaters responsive to the refrigerant temperature and pressure to deenergize said other resistance heater when the refrigerant charge level is insufficient for cooling leaving only said one resistance heater energized whereby the interconnected bimetal arms are moved into a closed operative position to close said contact pair to cause a relatively large current to pass through said fuse and to open it for deenergizing said compressor.

Claim 5

In an automobile air conditioning system including a refrigerant compressor driven by the automobile engine through an electromagnetic clutch which is energized by a circuit having a fuse, a compressor protective system comprising: a thermally biased relay including two cantilever mounted bimetal arms; each bimetal arm supporting a resistance wire heater connected in series with each other and with said fuse; the free ends of said bimetal arms being interconnected by an insulated link to cause said bimetal arms to move together; said relay having a pair of contacts connected between said fuse and ground and adapted to cause a relatively large current to flow through said fuse to open it when the contact pair is closed by a closing movement of said interconnected bimetal arms; the first resistance heater when energized biasing the interconnected bimetal arms toward a closed operative position; the second resistance heater when energized biasing said interconnected bimetal arms toward an open operative position; said contact pair being maintained open by simultaneous energization of both resistance heaters; a temperature and pressure responsive switch in heat transfer relation to refrigerant in the air conditioning system and in circuit with said resistance heaters and ground to cause said second resistance heater to be deenergized when said switch closes whereby said first resistance heater is energized separately and moves said interconnected bimetal arms to the closed position with said contact pair closed thereby opening said fuse and deactivating said electromagnetic clutch and said compressor.

Claim 6

In an automobile air conditioning system including a refrigerant compressor driven by the automobile engine through an electromagnetic clutch which is energized by a circuit having a fuse, a compressor protective system comprising: a thermally biased relay including two cantilever mounted bimetal arms; each bimetal arm supporting a resistance wire heater connected in series with each other and with said fuse; the free ends of said bimetal arms being interconnected by an insulated link to cause said bimetal arms to move together; said relay having a pair of contacts connected between said fuse and ground and adapted to cause a relatively large current to flow through said fuse to open it when the contact pair is closed by a closing movement of said interconnected bimetal arms; the first resistance heater when energized biasing the interconnected bimetal arms toward a closed operative position; the second resistance heater when energized biasing said interconnected bimetal arms toward an open operative position; said contact pair being maintained open by simultaneous energization of both resistance heaters; a temperature and pressure responsive switch in heat transfer relation to refrigerant in the air conditioning system and in circuit with said resistance heaters and ground to cause said second resistance heater to be deenergized when said switch closes whereby said first resistance heater is energized separately and moves said interconnected bimetal arms to the closed position with said contact pair closed thereby opening said fuse and deactivating said electromagnetic clutch and said compressor.

Claim 7

In an automobile air conditioning system including a refrigerant compressor, a compressor protector comprising: an electromagnetic clutch for interconnecting the automobile engine and said compressor for rotation together when said clutch is energized; circuit means including an electric power source and a fuse for energizing said electromagnEtic clutch; compressor protector means for producing a sufficiently large current through said fuse to open it and to deenergize said clutch when the refrigerant charge in said air conditioning system decreases below a level necessary for compressor cooling and lubrication; said compressor protector means including a thermally biased relay which normally holds open a pair of contacts between said fuse and ground; said relay having two bimetal arms which are cantilever mounted with their free ends interconnected for movement together by an insulative link; one of said contacts being mounted near the free end of one bimetal arm; a resistance wire heater around one of said bimetal arms which will cause the arms to move and close said contact pair when energized; switch means in circuit with said resistance wire heater and responsive to refrigerant temperature and pressure for energizing resistance wire heater when the refrigerant charge level is insufficient for cooling whereby the contact pair is closed and the large current flowing through said fuse causes it to open and deenergize said clutch.

Claim 8

In an automobile air conditioning system including a refrigerant compressor, a compressor protector comprising: an electromagnetic clutch for interconnecting the automobile engine and said compressor for rotation together when said clutch is energized; circuit means including an electric power source and a fuse for energizing said electromagnEtic clutch; compressor protector means for producing a sufficiently large current through said fuse to open it and to deenergize said clutch when the refrigerant charge in said air conditioning system decreases below a level necessary for compressor cooling and lubrication; said compressor protector means including a thermally biased relay which normally holds open a pair of contacts between said fuse and ground; said relay having two bimetal arms which are cantilever mounted with their free ends interconnected for movement together by an insulative link; one of said contacts being mounted near the free end of one bimetal arm; a resistance wire heater around one of said bimetal arms which will cause the arms to move and close said contact pair when energized; switch means in circuit with said resistance wire heater and responsive to refrigerant temperature and pressure for energizing resistance wire heater when the refrigerant charge level is insufficient for cooling whereby the contact pair is closed and the large current flowing through said fuse causes it to open and deenergize said clutch.

Claim 9

In an automobile air conditioning system including a refrigerant compressor, a compressor protector comprising: an electromagnetic clutch for interconnecting the automobile engine and said compressor for rotation together when said clutch is energized; circuit means including an electric power source and a fuse for energizing said electromagnetic clutch; compressor protector means for producing a sufficiently large current through said fuse to open it and to deenergize said clutch when the refrigerant charge in said air conditioning system decreases below a level necessary for compressor cooling and lubrication; said compressor protector means including a thermally biased relay which normally holds open a pair of contacts between said fuse and ground; said relay having two bimetal arms which are cantilever mounted with their free ends interconnected for movement together by an insulative link; one of said contacts being mounted near the free end of one bimetal arm; a resistance wire heater coactive with one of the bimetal arms which will cause the arm to move and close said contact pair; switch means coactive with said resistance wire heater and responsive to refrigerant temperature and pressure for regulating the energization of the resistance wire heater whereby when the refrigerant charge level is insufficient for cooling the contact pair is closed and the large current flowing through said fuse causes it to open and deenergize said clutch.

Claim 10

In an automobile air conditioning system including a refrigerant compressor, a compressor protector comprising: an electromagnetic clutch for interconnecting the automobile engine and said compressor for rotation together when said clutch is energized; circuit means including an electric power source and a fuse for energizing said electromagnetic clutch; compressor protector means for producing a sufficiently large current through said fuse to open it and to deenergize said clutch when the refrigerant charge in said air conditioning system decreases below a level necessary for compressor cooling and lubrication; said compressor protector means including a thermally biased relay which normally holds open a pair of contacts between said fuse and ground; said relay having two bimetal arms which are cantilever mounted with their free ends interconnected for movement together by an insulative link; one of said contacts being mounted near the free end of one bimetal arm; a resistance wire heater coactive with one of the bimetal arms which will cause the arm to move and close said contact pair; switch means coactive with said resistance wire heater and responsive to refrigerant temperature and pressure for regulating the energization of the resistance wire heater whereby when the refrigerant charge level is insufficient for cooling the contact pair is closed and the large current flowing through said fuse causes it to open and deenergize said clutch.