Abstract: A pneumatic hydraulic retractable device includes a fluid pressure cylinder having a cylinder body and a plug seat disposed in the cylinder body, a piston rod movably disposed in the fluid pressure cylinder, a control valve set having a valve seat disposed at the piston rod and forms an upper fluid chamber and a lower fluid chamber with the cylinder body therebetween, and a valve rod disposed in the valve seat for controlling communication between the upper and lower fluid chambers, and a pressure relief element forming a pressure relief gap with the piston rod. The pressure relief gap communicates with the lower fluid chamber through a communication portion of the pressure relief element. As such, when the valve rod is opened, the fluid is allowed to flow between the lower fluid chamber and the pressure relief gap through the communication portion for reducing airtight effect.

Abstract: A pneumatic hydraulic retractable device includes a fluid pressure cylinder having a cylinder body and a plug seat disposed in the cylinder body, a piston rod movably disposed in the fluid pressure cylinder, a control valve set having a valve seat disposed at the piston rod and forms an upper fluid chamber and a lower fluid chamber with the cylinder body therebetween, and a valve rod disposed in the valve seat for controlling communication between the upper and lower fluid chambers, and a pressure relief element forming a pressure relief gap with the piston rod. The pressure relief gap communicates with the lower fluid chamber through a communication portion of the pressure relief element. As such, when the valve rod is opened, the fluid is allowed to flow between the lower fluid chamber and the pressure relief gap through the communication portion for reducing airtight effect.

Abstract: A pneumatic-hydraulic control valve includes a valve base and a valve stem movably disposed in the valve base. A first inner oil guiding hole of the valve stem communicates with a first outer oil guiding hole of the valve base. A second inner oil guiding hole of the valve stem does not communicate with a second outer oil guiding hole of the valve base when the valve stem is closed, and communicates with the second outer oil guiding hole of the valve base when the valve stem is opened. Further, the valve stem has a first stressed portion for bearing a fluid closing force and a second stressed portion for bearing a fluid opening force. The outer diameter of the first stressed portion is larger than that of the second stressed portion. Thus, the present invention reduces a valve opening force without affecting the sealing effect.

Abstract: A pneumatic-hydraulic control valve includes a valve base and a valve stem movably disposed in the valve base. A first inner oil guiding hole of the valve stem communicates with a first outer oil guiding hole of the valve base. A second inner oil guiding hole of the valve stem does not communicate with a second outer oil guiding hole of the valve base when the valve stem is closed, and communicates with the second outer oil guiding hole of the valve base when the valve stem is opened. Further, the valve stem has a first stressed portion for bearing a fluid closing force and a second stressed portion for bearing a fluid opening force. The outer diameter of the first stressed portion is larger than that of the second stressed portion. Thus, the present invention reduces a valve opening force without affecting the sealing effect.