Abstract: A track adjusting flow controlling mechanism sets the optimum tension or "controlled sag" in the endless track of a track type vehicle. A piston and associated valve assembly control flow of pressurized fluid to a track adjusting clyinder. Movement of the piston tensions the track with substantially no sag ("S") and subsequent retraction of the piston provides correct track tension with an optimum track sag ("S"). Supply of pressurized fluid to the piston and valve assembly is controlled by the vehicle operator from the operator's station. Conventional track adjusting operations require considerable time and effort and are often an undesirable task. In view of this, the adjusting task is often neglected with the resulting rapid wear of the track and related components. The subject track adjusting mechanism provides a quick and simple operation to provide proper track adjustment.

Abstract: An underspeed actuator (18) is connected to the displacement control (17) for controlling the displacement of a variable displacement pump (11) of a hydrostatic transmission (10) in response to the pressure differential between low and high pressure control signals (A,B) wherein the pressure differential is directly proportional to the engine speed. An overspeed control valve means (41) is connected to the low and high pressure signals and decreases the pressure level of the high pressure signal received by the underspeed actuator (18) in response to the pressure differential exceeding a predetermined magnitude. This reduces the displacement of the variable displacement pump (11) thereby controlling the amount of engine overspeed caused by the hydrostatic transmission (10) driving the engine when the vehicle is descending a steep hill.

Abstract: A control arrangement comprises a pivotal control member having a pair of arms and a pivotal lever disposed between the arms. The stop member is secured on the lever to engage a snubber upon relative pivoting between the control member and lever. The control arrangement is adapted for connection to a control valve to alert the operator when the control lever has over-travelled a "run" condition of operation when the stop member engages the snubber.

Abstract: A fluid control circuit includes a source of pressurized fluid (10) adapted for connection to a hydrostatic transmission (23) upon actuation of a vent control valve (16). The vent control valve (16) is connected to a control and preconditioning valve (17) which functions to ensure that a control lever (14) is in its "vent" position upon starting of an engine and provides for the continuous preconditioning of the control circuit subsequent to such start-up. The control circuit is relatively non-complex in structure and function and does not require positioning of the control lever (14) in a special reset position upon shifting thereof between its "run" and "vent" positions.

Abstract: A fluid control cirucit for selectively varying the displacement of a variable displacement pump (P), such as the type employed in a hydrostatic transmission, comprises a primary control circuit connecting a pressurized fluid source (10) with the pump (P) and adapted to be actuated to selectively vary the displacement of the pump (P) between minimum and maximum values. A separate override control circuit is connected to the primary control circuit to override it to selectively vary the displacement of the pump (P).

Abstract: A control circuit comprises pressurized fluid source (11), a two-position directional control valve (14) and an actuator (13), such as the pump of a hydrostatic transmission, connected to the fluid source and the control valve to be selectively actuated thereby.

Abstract: A control circuit (10) for the variable displacement pump (18) of a hydrostatic transmission (16) or the like comprises an underspeed actuator (31) connected to the servo system (19) of the pump (18), a venturi (15) interconnected between a source of pressurized working fluid (11) and the pump (18) and a pressure regulating valve (36) interconnected between a downstream side of the venturi (15) and the pump (18). A throat (29) and upstream side of the venturi (15) are connected to the underspeed actuator (31) for communicating a differential fluid pressure signal thereto to automatically control the displacement of the pump (18) under certain operating conditions of an engine of a vehicle.