Patent ID: 6871575

Claim:
A hydraulic control apparatus for controlling a hydraulic cylinder for an implement selectively mounted to a work vehicle, comprising: a hydraulic power source; a four-position changeover control valve disposed between the hydraulic cylinder and the hydraulic power source; and an operational mechanism for operating the four-position changeover control valve; wherein the four-position changeover control valve has a first position for moving a rod of the hydraulic cylinder in one direction, a second position for stopping the rod of the hydraulic cylinder, a third position for moving the hydraulic cylinder rod at a high speed in the other direction with using a function of a regenerative circuit and a fourth position for moving the hydraulic cylinder rod in the other direction at a standard speed without using the function of the regenerative circuit, in the mentioned order; the operational mechanism includes, along an operational movement path thereof, a rollback position, a neutral position, a rapid dump position and a standard dump position, the rollback position corresponding to the first position, the neutral position corresponding to the second position, the rapid dump position corresponding to the third position, the standard dump position corresponding to the fourth position, respectively, and said operational mechanism includes a stopper plate for limiting the operational path of the mechanism to the rollback position, the neutral position and the rapid dump position.