Hydraulic circuit for a tractor drawn implement having remote variable height selector

Claim 1

In an agricultural machine including a tractor vehicle providing a source of hydraulic fluid and a trail behind implement supported on a plurality of hydraulically pivoted mounted wheels an implement height selector control comprising: a directional control valve in said tractor vehicle interposed between said source of hydraulic fluid and said trail behind implement; a rotory flow divider having a shaft connecting a plurality of rotors, said rotary flow divider hydraulically connected with said source of hydraulic fluid; a plurality of hydraulic motors downstream of said rotary flow divider communicating hydraulically through hydraulic conduit with said source of hydraulic fluid through said rotary flow divider, said plurality of hydraulic motors including sets of hydraulic motors corresponding to the number of rotary flow divider rotors; a revolution counter generator having a counter logic circuit incorporated in said rotary flow divider for counting revolutions of said shaft of said rotary flow divider; an adjustable count selector located in said tractor vehicle communicating clectrically with said revolution counter generator for determining the value at which said counter logic circuit of said revolution counter generator will produce an electrical signal; a solenoid operated check valve in a second hydraulic conduit electrically communicating with said revolution counter generator operatively responsive to hydraulic pressure on said hydraulic motor side of said rotary flow divider through a normally open switch; a plurality of counter balance valves, one of each of said counter balance valves interposed in said hydraulic conduit between one of each of said plurality of rotors of said rotary flow divider and each set of said plurality of hydraulic motors, said counter balance valves communicating hydraulically through pilot lines to said second hydraulic conduit, said counter balance valves set to open either through pressure in said hydraulic conduit or said second hydraulic conduit; a plurality of one-way check valves, one of each of said one-way check valves interposed in said hydraulic conduit between one of each of said pluralities of rotors of said rotary flow divider and each set of said plurality of hydraulic motors, said one-way check valve allowing flow from said rotary flow divider to said hydraulic motors; a plurality of one-way pilot operated check valves, one of each of said one-way pilot operated check valves associated with one of each of said sets of hydraulic motors, interposed in said second hydraulic conduit and pilot operated to open allowing fluid to pass from said hydraulic motors through said second hydraulic conduit.