Abstract: A double clutch system that allows the engine to drive the compressor of an OEM system through a first engaged clutch when the engine is running and allows an electric motor to drive the compressor through a second engaged clutch when the engine is not running. The electric motor is powered by either a power source external to the tractor's engine compartment (e.g., a electric outlet or an auxiliary power unit having a diesel-fired engine and a generator) or powered by the tractor battery, which is charged by a power source external to the tractor's engine compartment.

Abstract: A guide wire torque device has an elongate tubular body with interior long axial channel and a rotary clamp wheel for gripping and ungripping a guide wire extending through the channel. The clamp wheel is accommodated within an integral enlargement of the tubular body with a segment of the wheel surface extending through the surface of the enlargement for rotation by a user's thumb in order to grip and ungrip the guide wire for feeding, withdrawing or rotating the wire with respect to a catheter.