초록

A gas-operated valve actuator having a gas operated motor, a mechanism for disengaging the valve's manual operation apparatus, and a device for quickly shutting off the actuator when the valve's drive shaft reaches its travel limit.

대표청구항 ▼

1. A gas-operated valve actuator for rotating the input shaft of a valve, the actuator comprising: a body, selector valve means mounted to the body for selecting and permitting gas flow through either a forward motor line connected between a gas source and a motor means or a reverse motor line c

1. A gas-operated valve actuator for rotating the input shaft of a valve, the actuator comprising: a body, selector valve means mounted to the body for selecting and permitting gas flow through either a forward motor line connected between a gas source and a motor means or a reverse motor line connected between the gas source and the motor means, limit valve means mounted to the body in communication with each motor line for controlling the flow of gas in the respective line, motor means mounted to the body and operable by the gas from the gas source flowing through the selected motorline, the motor means connected to the input shaft for rotating it, and quick shutoff means for the limit valve means, the quick shutoff means mounted to the body and comprising: cam screw means mounted to the body in movable coaction with the input shaft via intermediate gears there between, said cam screw means having a fine pitched threaded portion and a course pitched threaded portion and a neutral area disposed between the threaded portions, major cam means movably mounted on the cam screw means, the major cam means provided with threads for coacting with the threaded portions of the cam screw means, tripping cam means movably mounted on the cam screw means, the tripping cam means provided with threads for coacting with the threaded portions of the cam screw means and disposed so that the major cam means moving on the fine pitched threaded portion moves to contact and urge the tripping cam means onto the course pitched threaded portion toward limit valve support means, limit valve support means pivotally connected to the body and supporting the limit valve means in open position, said limit valve support means disposed so that upon contact by the tripping cam means, the limit valve support means pivots thereby shutting off the limit valve means, control means for alternately shutting off the flow in the selected motor line when the input shaft reaches its travel limit. 2. The actuator of claim 1 wherein the valve to be actuated has manual operating means connected thereto and wherein the actuator has disengagement means mounted to the manual operating means for disengaging the manual operating means upon the application of gas to the actuator. 3. The actuator of claim 2 wherein the manual operation means includes a first shaft and a second shaft, the first shaft having manual rotation means mounted thereon and first clutch means mounted thereon, the second shaft having second clutch means mounted thereon and engageable with the first clutch means, the second shaft having engaging means for engaging the motor gear means, the second shaft interconnected with the input shaft of the valve to be actuated, and the disengagement means comprising: a clutch lever pivotally connected to the first clutch means and pivotally connected to the body, a gas operated clutch cylinder mounted to the body and having a clutch cylinder piston movably mounted therein, the piston disposed so that upon application of gas to the actuator the piston moves to contact and push the clutch lever which in turn pivots disengaging the first and second clutch means from each other and thereby preventing the manual rotation of the second shaft, motor gear means and the input shaft by means of the manual rotation means. 4. The actuator of claim 1 wherein an input line is disposed between the actuator and a gas power source for transmitting gas to the actuator and wherein the forward motor line is disposed between the motor means and the input line for providing the communication of gas between the input line and the motor means and wherein the reverse motor line is disposed between the motor means and the input line for providing the communication of gas between the motor means and the input line and wherein the control means is disposed between and in communication with the input line and both motor lines, and the control means includes: selector valve means for selectively permitting gas to flow from the input line through either the forward motor line or the reverse motor line, or for shutting off the gas from the input line so that no gas flows to either motor line, forward limit valve means having a movable first poppet mounted therein for controlling the flow of gas in the forward motor line, reverse limit valve means having a movable second poppet mounted therein for controlling the flow of gas in the reverse motor line, and exhaust valve means having an exhaust port to the atmosphere, the exhaust valve means disposed between the forward limit valve means and the reverse limit valve means and in communication with them so that gas flowing to one of the limit valve means will activate the exhaust valve closing off the exhaust port so that the gas passes down that limit valve means's respective motor line to the motor means, the exhaust valve means remaining in communication with the other limit valve means so that the gas passing through the motor means and into the other motor line and limit valve means will pass through the exhaust port to the atmosphere, the other limit valve closing off its motor line to the selector valve to insure that the gas is exhausted through the exhaust port. 5. The actuator of claim 4 wherein the motor means has a motor drive shaft extending therefrom and connected with the input shaft of the valve to be actuated and wherein the motor means has motor gear means mounted to the motor drive shaft, and wherein the control means has limit valve shutoff means comprising: a forward limit valve means support pivotally mounted to the body beneath the first poppet, a reverse limit valve means support pivotally mounted to the body beneath the second poppet, the poppet in the limit valve means through which gas is initially permitted to flow moving to contact and rest on its corresponding support, a cam screw having a midsection with fine pitch threads and two ends each with course pitch threads, a cam screw gear mounted to the cam screw, limit gear means disposed between and interconnected with the cam screw gear and the motor gear means for imparting the motion of the motor gear means to the cam screw gear so that rotation of the motor gear means results in rotation of the cam screw, two major cams movably mounted on the midsection of the cam screw, the major cams having threads for threaded movement on the cam screw as the cam screw turns, each major cam having a finger means mounted thereon, each finger means extending toward an opposite end of the cam screw, and two tripping cams one corresponding to each limit valve means support and disposed initially on the fine pitch thread of the cam screw, one on either side of the two major cams, each of the tripping cams being contactable by the finger means of its corresponding major cam so that upon contact the contacted tripping cam moves from the fine pitch thread of the cam screw onto the course pitch thread of the cam screw to contact and move its respective limit valve means support so that the limit valve means support pivots thereby releasing the corresponding poppet of the limit valve means, the poppet moving to close off the corresponding motor line so that the flow of gas to the motor means ceases.