Patent ID: 7152931

Claim:
A hydraulic circuit comprising: a hydraulic pump; a hydraulic actuator; an accumulator fluidly connected between the hydraulic pump and the hydraulic actuator, the accumulator including an inflow passage through which hydraulic fluid from the hydraulic pump is introduced into a hydraulic fluid chamber of the accumulator, and a discharge passage from which the hydraulic fluid from the hydraulic fluid chamber is discharged to the hydraulic actuator, the accumulator not operating when the pressure in the hydraulic fluid chamber is less than a set pressure and operating when the pressure in the hydraulic fluid chamber is at least the set pressure; and a valve mechanism which restricts the discharge of the hydraulic fluid from the hydraulic fluid chamber to the hydraulic actuator in a state in which the accumulator does not operate and which releases the restriction on the discharge of hydraulic fluid to the hydraulic actuator in a state in which the accumulator operates, wherein the valve mechanism has an air discharge passage which only discharges air from the hydraulic fluid chamber to the hydraulic actuator in the state in which the accumulator does not operate whereas the air discharge passage is not used for discharging when the accumulator operates.