Automatic hydraulic series-parallel shift device for implement

An hydraulic circuit for use in an implement for selectively driving first and second hydraulic motors in series at high speed and in parallel at low speed with increased torque, the circuit comprising:

• a source of flowing, pressurized hydraulic fluid;
• a spool valve receiving fluid from said source and having a slidable valve spool therewithin with an end surface portion;
• a first fluid line communicating from said fluid source to an inlet side of said first motor, to one end portion of said slidable spool of said spool valve, and to a first port of said spool valve;
• a second fluid line communicating from an outlet side of said first motor to a third fluid line through a check valve and to a third port of said spool valve;
• said third fluid line communicating from a second port of said spool valve to said inlet side of said second motor;
• a fourth fluid line communicating from an outlet side of said second motor to drain and to said third port of said spool valve;
• said valve spool forming flow channel means therein selectively connecting said first and second ports together and said third and fourth ports together in a first reciprocable position and blocking each of said ports in a second reciprocable position;
• and
• a spring means bearing on and biasing said valve spool in opposition to pressure imposed on said one end portion by fluid pressure in said first line,
• whereby said first and second motors operate at high speeds in series when said spool valve is in said second reciprocable position with low pressure in said first line but said motors operate at lower speed in parallel with higher torque when said valve spool is in said first reciprocable position upon increase in pressure in said first line.

Hydraulic circuit means for operating at least a pair of hydraulic motors selectively in series and in parallel as a function of a load on at least one of said motors, said circuit means comprising:

• first and second hydraulic motors having their power outputs interconnected for same speed rotation;
• a source of pressurized hydraulic fluid;
• first conduit means for directly communicating said source of fluid to drive the first of said hydraulic motors;
• valve means for receiving fluid from said source and selectively passing it to drive the second hydraulic motor in parallel operation with the first motor as a function of increased pressure in said first conduit means;
• second conduit means communicating fluid from said first motor selectively to drain and to drive the second hydraulic motor in lieu of said fluid passed through the valve means;
• and
• third conduit means directly communicating fluid from said second motor to drain.

An hydraulically operated manure spreader comprising in combination:

• a hopper in which material is hauled to be discharged and spread from a rearward end;
• upper and lower flinger rotors extending across the rearward end of the hopper for shredding and throwing piled material rearwardly of the hopper;
• first and second hydraulic motors mechanically interconnected for same speed rotation respectively connected to said upper and lower rotors for driving them in rotation;
• means for supplying a pressurized fluid to the motors for driving them;
• and
• valve means for controlling the flow of pressurized fluid to the motors in a first circuit arrangement wherein the motors are connected in parallel to share the pressurized fluid and operate at a lower speed, and a second circuit arrangement wherein the motors are connected in series to successively receive the pressurized fluid to operate at a higher speed whereby the rotors can be started in said first arrangement for removing material piled thereagainst and changed to the second arrangement for normal operation and emptying the remainder of the hopper.

An hydraulic drive for an implement comprising in combination:

• a first hydraulic motor in driving connection with a first member on the implement;
• a second hydraulic motor in driving connection with
• a second member on the implement,
• said members operable at a first lower speed at high torque or a second higher speed;
• linking means for maintaining same-speed rotation of the first and second members when one of the members is loaded differently than the other;
• a pressurized hydraulic fluid supply connected to said motors;
• valve means connected between the fluid supply and the motors;
• and
• an operator for said valve means selectively changing the valve means between a first and a second position, said valve means in said first position connecting the motors in parallel from the fluid supply and in the second position connecting the motors in series from the fluid supply.

The method of driving first and second rotary members such as beaters in a manure spreader which comprises:

• driving each beater individually with a hydraulic fluid operated motor;
• providing a common source of pressurized operating fluid to the motors;
• operating the motors in parallel slow speed, high torque relationship at the beginning of operation;
• providing a mechanical linkage to maintain same-speed rotation of the two beaters when one is loaded differently than the other during the parallel operation;
• and subsequently shifting to higher speed series operation wherein the motors are connected in series to receive the pressurized fluid so that initial resistances to load are overcome at high torque and the mechanism is then shifted to a higher speed operation.

A method for driving first and second rotating members, comprising the steps of:

• driving each member with a separate hydraulic fluid operated motor;
• providing a common source of pressurized operating fluid to the motors;
• mechanically linking the two members and fluid operated motors to insure same-speed operation when one of the motors is loaded differently than the other;
• automatically shifting the motors to parallel operation at slow speed and high torque when one of the motors is loaded above a predetermined load;
• and
• operating the motors in higher speed lower torque series operation when loads on the motors are below the predetermined load.