Abstract: A tracked vehicle is provided with an epicyclic steering differential interposed between the internal combustion engine and the track drive wheels. A reversible hydraulic motor is operatively associated with the differential for operating the steering of the vehicle. The differential includes a double epicyclic train which divides the torque from the internal combustion engine. The hydraulic motor acts on two elements of the train which are connected for rotation with each other about the central axis of the differential, and which rotate in equilibrium with each other when the vehicle is travelling a straight line.

Abstract: A shifting mechanism for the hydrostatic transmission of an earth moving machine comprising a shift lever manually operable by the machine operator to effect the speed and direction of movement of the vehicle. The shift lever is coupled to a hydraulically-actuated friction stop mechanism for maintaining the shift lever in a predetermined position by means of a fluid coupling which may be readily disconnected by the vehicle operator to adjust the positioning of the shift lever free from any frictional forces holding the shift lever in the prior position. A release system is provided wherein upon application of the vehicle brakes, the frictional force holding the shift lever in the predetermined position is released and the shift lever automatically returned to a neutral or idle position thereby disengaging the vehicle transmission.

Abstract: An hydraulic steering device for a crawler-mounted vehicle, in which a couple of pressure-regulating steering valves controls the rotation direction and speed of two respective rolling trains of the vehicle, is described. Each of the valves is provided with an end chamber having a piston sliding therein in response to a control pressure depending on the pilot pressure regulated by the other steering valve, and each piston is designed to shift respective shouldering means for respective contrast springs of respective shuttles provided on the valves in such a manner that both the rolling trains are stopped whenever both of the valves are activated simultaneously.

Abstract: A transmission shifting apparatus for controlling the speed and direction of movement of a vehicle. The transmission shifting apparatus utilizes an operating shift lever movable in a first direction through a plurality of successive positions in each of which it controls the forward movement of the vehicle at a predetermined speed, and a second opposed direction through a plurality of successive positions in each of which it controls the reverse travel of the vehicle at predetermined speeds. The shift lever is movable in a transverse direction between the first and second paths of movement to define a neutral or idle position in which no motion is imparted to the vehicle through the transmission. Movement of the transmission shift lever through the neutral position effects engagement of limit stops to retain the shift lever in the idle or neutral position.

Abstract: A hydraulic transmission system for tracked vehicles of the type comprising two separate hydrostatic transmissions for driving the right and the left tracks of the vehicle, each including a variable-displacement hydraulic pump provided with a hydraulically operated control for varying the pump displacement. There is provided a pressure regulating device interposed in the connection between the speed control device and the hydraulically operated control for the pumps of the two hydrostatic transmissions, which is arranged to increase and reduce the pressure supplied to the hydraulically operated control of one of the pumps so as to maintain the speeds of the two tracks equal. Preferably, the system further includes a sensor arranged to detect differences in speed of the two vehicle tracks and an actuator arranged to control the pressure regulating device in dependence on the signal received from the sensor.

Abstract: A remote controlled hydraulic circuit of the type comprising a source of pressurized fluid, a number of hydraulic motors connectible to the source of pressurized fluid, and control means for connecting the source of pressurized fluid to the hydraulic motors, the control means being remotely piloted by a series of pressure signals each of which corresponds to the opening of the connection between the source of pressurized fluid and a respective hydraulic motor. The hydraulic circuit according to the invention includes selector means for establishing priority for supplying pressurized fluid to one or more preferential hydraulic motors. These selector means are intended to detect, when operatively active, pressure signals corresponding to the supply of pressurized fluid to the preferential hydraulic motors and, in this condition, to render inoperative the control means associated with the other hydraulic motors, should they already have been activated to effect the supply of these other hydraulic motors.

Abstract: A manually-operable hydraulic control device of the hydraulic pressure liquid directional control type, with hydraulic position-retention, particularly for regulating the flow of pressurized fluid supplied to the power jack of a component or implement of an earth moving machine, comprises a pair of valves and a control lever having a central neutral position and two respective extreme operative positions for controlling the said valves. The device is provided with hydraulic means for retaining the control lever in at least one of the said extreme operative positions.

Abstract: A single lever control system for controlling the operation of multiple functions. A single control lever is coupled through linkage to effect individual movement of a plurality of valve spools in a hydraulic system and is supported for movement in predetermined paths to effect operation of the controls for the hydraulic system. Movement of the control lever effects operation of the hydraulic system in response to movement of the lever in a predetermined path.

Abstract: A hydraulic distribution manifold used to effect coupling of various hydraulic circuits and which includes at least one slidable valve spool whose movement is controlled by means of a crank mechanism operatively connected to a cam supported within the manifold and having at least two working surfaces for controlling movement of associated linkage.