Abstract: A grass cutting machine has two forward cutting units (24) and one rear central unit (46). The mechanism at, for example, the margin of a golf green, provides a time delay between lifting or lowering of the front (24) and rear cutting units (46) which is determined by the distance travelled by the machine. In this way it is ensured that all unites start and stop cutting at the same reference point on the ground.

Abstract: The descaling of surface of processing equipment, vessels and piping on which scale, such as that which occurs in the extraction of alumina from bauxites has formed. The surface is cleaned to ensure that it is entirely free of contaminants and then is coated with a suitable resin such as an epoxy resin which is cross linked and thermosetting. The coating may be applied in two or more layers using the same or a different resin. The final layer may be one which readily detaches from the base coating when subjected to a high pressure fluid blast.

Abstract: A fuel-air mixture regulator for multiple cylinder four-cycle internal combustion engines is positioned between the carburetor and the intake manifold whereby the fuel and air mixture flowing from the carburetor passes through the fuel-air mixture regulator and undergoes an increase in velocity and turbulence enroute to the cylinders for better combustion. The mixture regulator includes a housing having a plurality ports. A thin, resilient, flexible reed for each port is adapted to seat thereover when the engine is not operating and moves away from the port to variably open same for flow of fuel-air mixture therethrough in response to pressure differentials on the reeds during engine operation. The size of the port opening is reduced at lower engine speeds and assures optimum fuel-air mixing and high velocity air flow even at such lower speed.