Shaft Structure in a Pneumatic Actuator

Abstract

An improved structure of a central shaft in a pneumatic actuator comprises an actuator having an actuator chamber; a vane which is hingedly located at a shaft hole of the actuator. The central shaft is cylindrical and short, and the short central shaft has a through hole which is a through octagonal opening symmetric to a center thereof. It can be easily processed and precisely aligned. The advantage of the short central shaft is that the actuator itself can connect to non-pressured sources such as an upper and lower central shafts, and connect to different inserting drivers to form a central shaft as a unit in the pneumatic actuator to directly connect to a central shaft of a valve or indirectly through a connecting bracket instead of using a conventional connecting coupler. The octagonal opening provides alignment positions at every 45 degrees for the upper and lower central shafts to increase diversities of usage.

1 . An improved structure of a central shaft in a pneumatic actuator, comprising:
 a vane, which has a short central shaft having a through octagonal opening symmetric to a center thereof;   an upper central shaft, which has a first square block adapted to insert into the through octagonal opening to occupy four corners symmetric to the center of the octagonal opening, and a non-through inner screw hole inside a bottom surface of the square block;   a lower central shaft, which has a second square block corresponding to the symmetric center of the through octagonal opening, wherein the second square block is inserted into the through octagonal opening to occupy four corners symmetric to the center of the octagonal opening, and the second square block has a through hole inside a top surface thereof, and a bottom surface of the lower central shaft has an upward circular opening which has a key groove around the periphery of the circular opening; and   an inserting driver, which has a through assembled opening at a center thereof and is designed as a cylinder equal to the upward circular opening of the lower central shaft, and a key slot is formed at a surrounding surface, wherein the inserting driver is configured to be inserted into the circular opening of the lower central shaft; a key element, which is located at the key groove of the lower central shaft and the key slot of the inserting driver; a screw which is fastened at the inner screw hole of the upper central shaft through the through hole of the lower central shaft and the through octagonal opening symmetric to a center of the short central shaft.   
     
     
         2 . The improved structure of a central shaft in a pneumatic actuator of  claim 1 , wherein the through assembled opening of the inserting driver is a square opening, an octagonal opening, an oval-shaped opening or a polygonal opening. 
     
     
         3 . The improved structure of a central shaft in a pneumatic actuator of  claim 1 , wherein the lower central shaft is connected to a first valve body. 
     
     
         4 . The improved structure of a central shaft in a pneumatic actuator of  claim 3 , wherein the upper central shaft is connected to a display screen. 
     
     
         5 . The improved structure of a central shaft in a pneumatic actuator of  claim 3 , wherein the upper central shaft is connected to a positioning device. 
     
     
         6 . The improved structure of a central shaft in a pneumatic actuator of  claim 3 , wherein the upper central shaft is connected to a second valve body. 
     
     
         7 . The improved structure of a central shaft in a pneumatic actuator of  claim 3 , wherein the lower central shaft of the pneumatic actuator is equipped with a connecting bracket, and the lower central shaft longer than a conventional connecting coupler is chosen, so the lower central shaft is directly connected to the first valve body.