Compressor shaft seal heater

Claim 2

In a vehicle air conditioning system for use in a vehicle having an engine and ignition switch and in which the system has prolonged periods of non-operation while the vehicle is being normally operated, a compressor including a fluid seal assembly disposed between surfaces that move relative to each other when the compressor is mechanically driven and subject to damage when the compressor is mechanically driven after being subjected to cold weather conditions during the periods of non-operation, a lubricating pump driven when said compressor is mechanically driven supplying lubricant to said fluid seal assembly, said lubricant and said seal assembly responsive to cold weather conditions tending to bond the relatively movable compressor surfaces together, the improvement comprising: a clutch selectively drivingly connecting said compressor with the vehicle engine, a solenoid including a coil effective when energized to actuate said clutch and drivingly connect said compressor with the vehicle engine, said solenoid further being in thermal communication with said surfaces, control circuitry including the engine ignition switch energizing said solenoid, means defining a first current path in said control circuitry from said ignition switch to said solenoid coil for actuating said clutch and connecting said compressor with the vehicle engine, means defining a second current path from said ignition switch to said solenoid coil supplying said coil with a reduced current flow insufficient to actuate said clutch but of a sufficient magnitude to generate heat in said coil and warm the fluid seal assembly to a non-bonding temperature, and ambient temperature sensing means responsive to ambient temperatures above a predetermined range for completing the circuit through said means defining said first current path and movable in response to low predetermined temperatures to open said means defining said first current path and close said means defining said second current path whereby said solenoid coil operates as a heater during low ambient temperature conditions.

Claim 3

In a vehicle air conditioning system for use in a vehicle having an engine and an ignition switch and in which the system has prolonged periods of non-operation while the vehicle is being normally operated, a compressor including a fluid seal disposed between surfaces moving relative to each other when the compressor is mechanically driven and subject to damage when the compressor is mechanically driven after being subjected to cold weather conditions during the periods of non-operation, a lubricating pump driven when said compressor is mechanically driven supplying lubricant to said fluid seal, said lubricant and said seal responsive to cold weather conditions tending to bond the relatively movable compressor surfaces together, the improvement comprising: a clutch selectively drivingly connecting said compressor with the vehicle engine, a solenoid including a coil effective when energized to actuate said clutch, said solenoid being in therMal communication with said surfaces, control circuitry including the ignition switch energizing said solenoid, means defining a first current path connecting said ignition switch to said solenoid coil for energizing said clutch and connecting said compressor with the vehicle engine, means defining a second current path connecting said ignition switch with said solenoid coil, a resistance in said means defining a second current path regulating the flow of current to said solenoid coil whereby the current received by the solenoid coil through said second path and said resistance is inadequate to energize said clutch and connect said compressor with the vehicle engine but is sufficient to energize the solenoid coil generating heat sufficient to warm said fluid seal during cold weather conditions, and an ambient temperature sensing switch regulating the flow of current through both of said means defining said first and second current paths, said switch responding to temperatures above a predetermined value to complete the circuit through said means defining said first path providing for energization of said solenoid coil and connection of the compressor with the vehicle engine, said switch responding to a predetermined lower temperature during cold weather conditions moving to open the circuit through said means defining said first current path and closing the circuit through said means defining said second current path whereby said solenoid coil is energized warming the fluid seal.

Claim 4

In a vehicle air conditioning system for use in a vehicle having an engine and an ignition switch and in which the system has prolonged periods of non-operation while the vehicle is being normally operated, a compressor including a fluid seal disposed between surfaces moving relative to each other when the compressor is mechanically driven and subject to damage when the compressor is mechanically driven after being subjected to cold weather conditions during the periods of non-operation, a lubricating pump driven when said compressor is mechanically driven supplying lubricant to said fluid seal, said lubricant and said seal responsive to cold weather conditions tending to bond the relatively movable compressor surfaces together, the improvement comprising: a clutch selectively drivingly connecting said compressor with the vehicle engine, a solenoid including a coil effective when energized to actuate said clutch, said solenoid being in therMal communication with said surfaces, control circuitry including the ignition switch energizing said solenoid, means defining a first current path connecting said ignition switch to said solenoid coil for energizing said clutch and connecting said compressor with the vehicle engine, means defining a second current path connecting said ignition switch with said solenoid coil, a resistance in said means defining a second current path regulating the flow of current to said solenoid coil whereby the current received by the solenoid coil through said second path and said resistance is inadequate to energize said clutch and connect said compressor with the vehicle engine but is sufficient to energize the solenoid coil generating heat sufficient to warm said fluid seal during cold weather conditions, and an ambient temperature sensing switch regulating the flow of current through both of said means defining said first and second current paths, said switch responding to temperatures above a predetermined value to complete the circuit through said means defining said first path providing for energization of said solenoid coil and connection of the compressor with the vehicle engine, said switch responding to a predetermined lower temperature during cold weather conditions moving to open the circuit through said means defining said first current path and closing the circuit through said means defining said second current path whereby said solenoid coil is energized warming the fluid seal.

Claim 5

In a vehicle air conditioning system for use in a vehicle having an engine and an ignition switch and in which the system has prolonged periods of non-operation while the vehicle is being normally operated, a compressor including a fluid seal disposed between surfaces that move relative to each other when the compressor is mechanically driven, the fluid seal being subject to damage by bonding of relatively rotatable surfaces when the compressor is mechanically driven after being subjected to prolonged periods of non-operation during cold weather conditions, a lubricatng pump driven when said compressor is mechanically driven supplying lubricant to said fluid seal, said lubricant and said seal responsive to cold weather conditions tending to bond the relatively movable compressor surfaces together, the improvement comprising: a clutch selectively drivingly connecting said compressor with the vehicle engine, a solenoid including a coil effective when energized to actuate said clutch, control circuitry including the engine ignition switch energizing said solenoid, means defining a first current path in said control circuitry connecting said ignition switch with said solenoid coil for energization of said clutch connecting said compressor with the vehicle engine, means defining a second current path connecting said ignition switch with said solenoid coil, said means defining said second current path including a resistance of a predetermined value regulating current flow to said solenoid coil so as to supply the coil with a current sufficient to energize the coil and generate heat warming said fluid seal but insufficient to energize said clutch, said resistance and said solenoid coil both being in thermal communication with said relatively rotatable surfaces, so that both act as heaters when the circuit through said means defining said second current path is completed, an ambient temperature sensing switch including a pair of spaced contacts in said means defining said first current path and a pair of spaced contacts in said means defining said second current path, and a bimetallic disk disposed between the spaced contacts in both of said current paths so that said disk responds to temperatures above a predetermined value to snap into engagement with the spaced contacts in said means defining said first current path completing the circuit from said ignition switch to said solenoid coil for energization of said clutch, said bimetallic disk being responsive to a predetermined lower temperature and snApping into engagement with the spaced contacts in said means defining said second current path completing the circuit through said resistance from said ignition switch to said solenoid coil thereby warming the fluid seal.

Claim 6

In a vehicle air conditioning system for use in a vehicle having an engine and an ignition switch and in which the system has prolonged periods of non-operation while the vehicle is being normally operated, a compressor including a fluid seal disposed between surfaces that move relative to each other when the compressor is mechanically driven, the fluid seal being subject to damage by bonding of relatively rotatable surfaces when the compressor is mechanically driven after being subjected to prolonged periods of non-operation during cold weather conditions, a lubricatng pump driven when said compressor is mechanically driven supplying lubricant to said fluid seal, said lubricant and said seal responsive to cold weather conditions tending to bond the relatively movable compressor surfaces together, the improvement comprising: a clutch selectively drivingly connecting said compressor with the vehicle engine, a solenoid including a coil effective when energized to actuate said clutch, control circuitry including the engine ignition switch energizing said solenoid, means defining a first current path in said control circuitry connecting said ignition switch with said solenoid coil for energization of said clutch connecting said compressor with the vehicle engine, means defining a second current path connecting said ignition switch with said solenoid coil, said means defining said second current path including a resistance of a predetermined value regulating current flow to said solenoid coil so as to supply the coil with a current sufficient to energize the coil and generate heat warming said fluid seal but insufficient to energize said clutch, said resistance and said solenoid coil both being in thermal communication with said relatively rotatable surfaces, so that both act as heaters when the circuit through said means defining said second current path is completed, an ambient temperature sensing switch including a pair of spaced contacts in said means defining said first current path and a pair of spaced contacts in said means defining said second current path, and a bimetallic disk disposed between the spaced contacts in both of said current paths so that said disk responds to temperatures above a predetermined value to snap into engagement with the spaced contacts in said means defining said first current path completing the circuit from said ignition switch to said solenoid coil for energization of said clutch, said bimetallic disk being responsive to a predetermined lower temperature and snApping into engagement with the spaced contacts in said means defining said second current path completing the circuit through said resistance from said ignition switch to said solenoid coil thereby warming the fluid seal.