Hydraulic stroke locking mechanism for pneumatic actuator

The invention relates to a hydraulic stroke locking mechanism for a pneumatic actuator. The upper end of an upper piston rod of a double-piston-rod hydraulic cylinder upwardly penetrates out of the center of an upper cylinder cover, and the lower end of a lower piston rod downwardly penetrates out from the center of a lower cylinder cover; a piston rod stroke limit component is mounted on the upper cylinder cover; the lower cylinder cover is fixedly mounted on a support, the lower piston rod is inserted into the support from a piston rod insertion hole from top to bottom, and the lower end of the lower piston rod is fixedly connected with the upper end of a push rod of the pneumatic actuator. The hydraulic stroke locking mechanism is reasonable in structure and safe and reliable to operate, has two functions of valve position locking and manual operation, can quickly lock the push rod of the pneumatic actuator at any position in a stroke range together with a valve spool component of a valve and is simple and laborsaving to operate; besides, the hydraulic stroke locking mechanism can serve as a hydraulic manual device used for operating the valve in emergencies, emergency stop of a device after valve fault is avoided, the pneumatic actuator applying the hydraulic stroke locking mechanism does not need to be added with a handwheel mechanism, and cost waste is avoided.