Abstract: A fluid flow equalizing valve has two coupled valve devices for controlling flow to or from a common connection to respective ones of a pair of actuators. Control elements of the valve devices are responsive to intermediate pressures in flow paths to or from the actuators, and move in unison to reduce any difference in the intermediate pressures, and thereby to maintain the flows to or from the respective actuators substantially equal.

Abstract: A level lift system for an implement in which a main frame is flexibly connected to outrigger frames with a wheel assembly carried by each frame. A hydraulic ram is operably connected between each frame and the associated wheel assembly with the rams connected in parallel and with a rotary flow divider interposed in the connection with one end of said rams, whereby fluid pressure is directed to said one end when connected with a pump and fluid is exhausted from said one end when connected with a reservoir. Flow to and from said one end being at substantially equal rates regardless of the relative resistance encountered by said rams.

Abstract: A hydraulic synchronizing system which comprises a double piston power source and a drain valve in fluid communication with the hydraulic lift cylinders of a vehicle mounted vibratory seismic energy source. The double piston power source supplies the hydraulic lift cylinders with substantially equal volumes of hydraulic fluid, and the drain valve adjusts the flow of hydraulic fluid out of the hydraulic lift cylinders. The system synchronizes the operation of the hydraulic lift cylinders and thus coordinates movement of the vibrator guide rods relative to the vehicle upon which the vibrator is mounted.