Patent ID: 8146221

Claim:
A hydraulic tool, performing an external-pulling operation for an object to be disassembled, and having an outer periphery and a shaft comprising: clamping jaws; an oil pressure tank; an axial shaft; an oil storage member; and a handle fixed to a control valve movable toward a side to move the oil pressure tank forward, with oil from an inlet of the oil storage member flowing into the oil pressure tank via a first oil passage to push a piston of the oil pressure tank outward, wherein the axial shaft connected at an end of a piston rod is also pushed outward, and wherein at the same time, when the pressure of the oil flowing into the oil pressure tank reaches a maximum value, the oil will flow through an oil chamber inside of the piston rod to a second oil passage and then flow through a third oil passage into a return passage, and finally flow back into the oil storage member via a fourth oil passage at one end of the inlet of the oil storage member, with each of the clamping claws pressing against the outer periphery and the axial shaft pushing against the shaft of the object.