Piston stop for piston operated valve

Claim 2

In a valve operator for a gate valve having a reciprocatiNg stem and movable between open and closed positions, a housing having the stem extending concentrically therethrough, a piston secured to the stem and mounted within the housing for reciprocable movement, and a generally cylindrical piston stop mounted within the housing inwardly of the piston and contacting an inner surface of the piston upon the piston reaching its inner position in the open position of the gate valve, said piston stop having external screw threads mating with internal screw threads on the housing for adjustable movement in a longitudinal position relative to the piston, said housing having an opening in the wall thereof adjacent the piston stop to permit access to the piston stop from a position outside the housing, said piston stop having indentations therein adapted to be engaged by a manual tool for adjusting the stop.

Claim 3

In a valve operator for a gate valve as set forth in claim 1, a coil spring about the stem and contacting an inner surface of the piston for urging the piston to its outer position, said cylindrical piston stop receiving said coil spring.

Claim 4

A gate valve structure comprising a main valve body having an axial fluid flow passage, a gate valve member in the valve body having a port therein adapted to align with the flow passage in an open position and to close the flow passage in a closed position, a stem attached to said valve member and extending outwardly of the main body, a hydraulic cylinder including a relatively large diameter housing and a relatively small diameter housing receiving the stem, a piston secured to the stem and mounted within the relatively large diameter housing for reciprocable movement between inner and outer positions, and a generally cylindrical piston stop mounted within the relatively small diameter housing inwardly of the piston and contacting an inner surface of the piston upon the piston reaching its inner position in the open position of the gate valve member, said relatively small diameter housing having an opening in the wall thereof adjacent the piston stop to permit access to the piston stop from a position outside the small diameter housing, said piston stop having external screw threads mating with internal screw threads on the cylinder for adjustable movement in a longitudinal position relative to the piston.

Claim 5

A gate valve structure comprising a main valve body having an axial fluid flow passage, a gate valve member in the valve body having a port therein adapted to align with the flow passage in an open position and to close the flow passage in a closed position, a stem attached to said valve member and extending outwardly of the main body, a hydraulic cylinder including a relatively large diameter housing and a relatively small diameter housing receiving the stem, a piston secured to the stem and mounted within the relatively large diameter housing for reciprocable movement between inner and outer positions, and a generally cylindrical piston stop mounted within the relatively small diameter housing inwardly of the piston and contacting an inner surface of the piston upon the piston reaching its inner position in the open position of the gate valve member, said relatively small diameter housing having an opening in the wall thereof adjacent the piston stop to permit access to the piston stop from a position outside the small diameter housing, said piston stop having external screw threads mating with internal screw threads on the cylinder for adjustable movement in a longitudinal position relative to the piston.