The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Apr. 29, 1986
Filed:
Sep. 03, 1985
William S Shelton, Houston, TX (US);
Joy Manufacturing Company, Pittsburgh, PA (US);
Abstract
A piston type pneumatic powered actuator (9) for operating a valve (10) of the expanding gate type wherein velocity of the piston-stem-gate drive train is maintained substantially constant in the latter stage of the actuator stroke. The actuator (9) includes an assembly of dual pistons (61,75) which are adapted to be driven by fluid pressure in one direction to operate the valve but are returned by spring means (66,67) when the fluid pressure is removed. A drive piston (61) directly connected to the actuator stem (23) is nested within a primary piston (75) which is not connected to the actuator stem (23) but moves the drive piston (61) when actuating pneumatic fluid is applied to the actuator (9). A stop (85) affixed to the primary piston (75) is adapted to cooperatively engage the actuator housing (40) to terminate the stroke of the primary piston (75) prior to termination of the stroke of the drive piston (61). An orifice (91) through the primary piston (75 ) allows continuing flow of actuating fluid to the face of the drive piston (61) after the stroke of the primary piston (75) is terminated. Termination of the stroke of the primary piston (75) occurs when fluid communication through the valve is first established.