Abstract: A high pressure cleaning head for cleaning surfaces and including a rotatable spray head having rotatable spray arms for directing a cleaning agent to surface to be cleaned by successive overlapping passes of the cleaning head; and a diffuser to inhibit the cleaning action of the spray arms on at least one side of the cleaning head and thereby prevent striping on the surface to be cleaned due to the overlapping passes of the cleaning head.

Abstract: Hydraulically actuated grapple tongs mounted to a log skidder are useful, for example, in gripping a bunch of logs that are being dragged from one site to another. Maintaining a grip on the logs during the dragging operation with known hydraulic systems generates heat within the hydraulic systems. The subject hydraulic system includes first and second variable displacement load sensing pumps commonly connected to a control valve which controls fluid flow to an actuator. A load pressure signal is directed through a first signal line to a displacement controller of the first pump and to a pressure responsive valve normally resiliently biased to a position at which the first signal line is communicated to a displacement controller of the second pump. When the load pressure signal in the first signal line exceeds a predetermined value, the valve is moved to a position blocking communication of the load signal to the displacement controller of the second pump.