Abstract: The efficiency of a fan clutch is improved by having a central finned cover attached to the fan clutch at its rotational axis with fins or blades thereon to disperse air radially outwardly from a dead air bubble at the rotational axis of the fan. This is achieved by a cover having a disk-shaped body with fan fins extending from the rotational axis outwardly to the rim of the disk-shaped body to move air from the rotational axis to prevent the build-up of a negative pressure at the rotational axis and this air flow from the rotational axis into the clutch fan blades appreciably increases the total air flow by the fan clutch. The preferred fins are curved between their inner ends at the rotational axis and their outer ends which extend to the fan blades of the fan clutch. The fins may wrap around the rim of the disk-shaped body and the latter may have a curved outer, front surface.

Abstract: A method and apparatus are used to balance an open blade fan of the kind used with trucks, diesel engine driven generator sets, and the like. An apparatus is used to spin the fans and a vibration sensor senses vibrations and a light beam is used to indicate the location to attach a balancing weight. The fan is spun again and the vibrations measured and additional weights are attached at different specified locations until the measured vibrations are below a predetermined level. The fan includes a plastic body with integral, plastic fan blades which is attached to a central metal hub plate with configured weights attached to matching configured portions of the plastic body. The preferred weights are clips with barbs that pierce the plastic body. The metal hub plates are electrostatically painted to provide a uniformly thick coating with good adhesion.

Abstract: A magnetic fan clutch having a magnetic field coupling which uses a light weight, strong plastic driving member and driven member to rotate fan blades which are also made of plastic. The fan clutch also uses a plastic mounting member for attaching to a vehicle. Plastic may be used for a vehicle or truck fan clutch because the magnetic coupling between the series of coils on the driving member and the magnetic elements on the driven member may be modulated to provide a slower torque transfer from zero to a full torque transfer over a longer controlled period of time such as over six seconds to eliminate the relatively sharp impact torque transfer pulse heretofore found in fan clutches. This slower and modulated torque transfer with slippage between the driving member and driven member during the torque transfer period reduces the fast acceleration and the resistant high inertia and torque loads of conventional fan clutches as typically found in vehicles or other heavy duty applications.

Abstract: A drive for the compressor of a vehicle air conditioner has a magnetic clutch for mechanically driving the compressor shaft within a predetermined range of torque and a rotatable input element on the magnetic clutch to be rotated by the vehicle motor at varying speeds with changes in the vehicle motor's speed. The drive includes a first electromagnetic element on the rotatable input element and a compressor shaft on the output side of the magnetic clutch for supplying torque to drive the compressor. Also, there is a second electromagnetic element on the compressor shaft with a magnetic field between the first and second electromagnetic elements to rotate the compressor. An electric control is provided for varying the electrical power to the electromagnetic clutch as the vehicle motor changes speed to vary the magnetic field and torque being applied to rotate the compressor shaft.

Abstract: A new and improved fan clutch system for use with an internal combustion engine which provides variable speed drive of the fan by the engine with the coupling between the fan and the engine being solely by a magnetic field. The variable speed drive provides true proportional control of the convective heat transfer from the radiator.