Patent ID: 7908852

Claim:
A control circuit comprising: a swing motor, the swing motor having a first port and a second port, the swing motor moving in a first direction when a flow of hydraulic fluid flows into the swing motor through the first port, the swing motor moving in a second direction when a flow of hydraulic fluid flows into the swing motor through the second port, the second direction being opposite to the first direction; first and second motor conduits, the first motor conduit connected to the first port of the motor, the second motor conduit connected to the second port of the motor; a pump adapted to selectively provide a flow of hydraulic fluid to the swing motor through the first and second motor conduits; an accumulator system including a pressure-controlled selection valve and an accumulator, the selection valve hydraulically connected to the first and second motor conduits and to the accumulator and being movable between a first open position, wherein a flow path between the first port of the swing motor and the accumulator is defined, and a second open position, wherein a flow path between the second port of the swing motor and the accumulator is defined, the selection valve being disposed in the first open position when the pressure in the first motor conduit is greater than the pressure in the second motor conduit, and the selection valve being disposed in the second open position when the pressure in the second motor conduit is greater than the pressure in the first motor conduit; and an accumulator charge valve in series between the selection valve, the accumulator charge valve being movable between a first open position, wherein a one-way flow path towards the accumulator is defined, and a second open position, wherein a one-way flow path towards the selection valve is defined.