Abstract: A portable dental delivery system is provided which is composed of a plurality of individual module sections. The portable delivery system provides all basic tools and accessories which are necessary for a dentist to perform all types of dental work which may be required by patients. The dental delivery system includes a quiet running, pressurized clean air supply system for operating the various tools and accessories utilized by the dentist. A hermetically enclosed refrigeration compressor unit is modified to provide an adequate supply of pressurized air in an extremely quiet manner. The temperature of the compressor unit is maintained at a safe level by an oil cooling system. A pump draws oil from the base of the compressor unit, passes it through a radiator which is additionally cooled by an axial fan. The oil is returned to the compressor unit at the top of the housing at a location which will cause the oil to impinge directly upon the cylinder head of the compressor.

Abstract: A hydraulically operable elevator having a vertically reciprocable cab suspended from an overhead structure by differential hydraulic piston systems which are responsive to introduction of hydraulic fluid to decrease the overall length of the differential pistons causing the cab to ascend, and which are responsive to withdrawal of hydraulic fluid from the piston assemblies to increase the overall length of the differential pistons, allowing the cab to descend. Only one differential piston assembly is required on each side of the transverse axis of the cab to increase its stability and to provide maximum cross-sectional area for the interior of the cab.