Patent ID: 8517698

Claim:
An air conditioning compressor assembly comprising: a compressor operable to compress material within the compressor and driven by a drive shaft, said compressor capable of exhibiting an over-torque condition; An accessory drive coupled to a rotor; an electromagnetic clutch interposed between the compressor and the accessory drive, wherein the electromagnetic clutch is operable to an engaged state by urging the rotor and an armature of the electromagnetic clutch together via magnetic force from a magnetic field generated in the rotor, thereby coupling the accessory drive to the compressor for operating the compressor, and wherein the electromagnetic clutch is operable to a disengaged state which decouples the compressor and the accessory drive; a frangible element adapted to fracture when the over-torque condition occurs; A lifting feature fixed to the armature; a ramp that is in a fixed position relative to the compressor drive shaft; wherein the ramp defines a helical ridge, and the lifting feature defines a lifting ridge engaging the helical ridge, wherein when the frangible element fractures, relative rotation between the lifting feature and the ramp exerts an axial mechanical force in opposition to the magnetic force that also overcomes the magnetic force, and the ramp moves the armature apart from the rotor which also decouples the compressor and the accessory drive.