Abstract: A hydraulic system 10 provides a positive supply of hydraulic fluid at a controlled pressure to plurality of pumps. The system comprises a fluid reservoir 15 having outlet means to supply fluid to an auxiliary pump 30. A pressure chamber 16 communicates with a reservoir 15 and has outlet means to supply fluid to a plurality of working pumps 11, 12, 13. An inlet manifold 18 is provided for receiving fluid returned from the working and auxiliary pumps.

Abstract: An exhauster fan system for a road sweeping machine comprises a rotatable fan, a drive, and a hydrostatic transmission system coupled between the drive and a spindle on which the fan is mounted. The output of the transmission system is controlled to apply a constant torque to the fan spindle. The transmission system comprises a variable displacement pump coupled to drive a fixed displacement motor. A pressure control is associated with the pump to control hydraulic oil flow in the pump to sustain a set pressure in the motor. The pressure control is selectively operable to provide different set pressures to the motor for different operating conditions. The fan is used in the environment of a road sweeping vehicle comprising a chassis, an airtight container mounted on the chassis, at least one suction conduit connected to the container and, positioned within the container, the described exhauster fan system in which the fan creates a high velocity air flow within the suction conduit.

Abstract: This invention relates to improved control systems for vehicles which require power to prepare the vehicle itself and to drive auxiliary equipment mounted on the vehicle. A land vehicle has hydrostatic transmission to drive at least one roadwheel to propel the vehicle, an engine connected to drive both the hydrostatic transmission and auxiliary equipment mounted on the vehicle, a hydraulic pressure supply to the transmission and a speed control for the vehicle. The speed control controls the pressure supply of the transmission and the speed of the engine whereby the engine speed is restricted to a preset limit when the auxiliary equipment is operating and the speed of the engine can be increased when the auxiliary equipment is inert and the vehicle in transit. This results in a more efficient and better controllable vehicle, particularly working vehicles such as roadsweepers, agricultural and construction vehicles.

Abstract: A fan impeller comprises a back plate, a front plate and a plurality of blades lying between the front and back plates, wherein the blades are fitted relative to the axis of rotation of the impeller to provide a leading edge adjacent the back plate, so as to impart, in use, a lateral sideways vector to a stream of and passing along the blades. At least two of the blades may be of increased thickness than the remaining blades. These improvements increase the life of the fan impeller significantly.

Abstract: A suction type road sweeping vehicle generally has a self propelled chassis with road wheels. Mounted on the chassis is an air tight container for collecting dust etc. swept up by the vehicle. Dust etc. is sucked up into the container via pick up conduits and nozzles, the suction being provided by a fan. When hydraulically driven brushes and the like are used the hydraulic oil must be cooled. This is effected by introducing water into the conduits to mix with the cooling stream of air flowing into the container, separating the cooled water from the air and debris and utilizing the cooled water to cool the hydraulic oil.

Abstract: A suction type road sweeping vehicle utilizes a suction fan for generating a vacuum within an air tight container mounted on the chassis. Suction conduits extend at one end into the container and are provided at the other end with nozzles. A sound attenuation system connected to an outlet duct of the fan comprises an expansion duct inside which is mounted a perforated panel connected to an attenuation duct, whose outlet exhausts to the atmosphere. Air expelled from the fan passes into the expansion duct, through the perforated panel which acts to raise the frequency of the sound of the air and through the attenuated duct, which has a noise absorbing lining which absorbs the sound as the air passes through the duct before being exhausted to atmosphere. Thus, the noise emitted by such road sweepers which, by the very nature of their construction and operation, are noisy vehicles, may be substantially reduced without hindering the flow of discharged air.

Abstract: A suction type road sweeping vehicle includes a fluid coupling in the drive train between the auxiliary engine and the vacuum generating fan. The fluid coupling is mounted integrally with the engine flywheel and drives a step up gearbox. The flywheel, coupling and gearbox are housed in a compact housing attached to the engine and routine in the coupling. The use of the fluid coupling alleviates vibrational problems associated with elastic properties in existing couplings and thereby enables a more robust fan having a greater moment of inertia to be used.