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:
Dec. 06, 1988
Filed:
Sep. 09, 1987
Applicant:
Inventor:
William D Vork, Edina, MN (US);
Assignee:
Graco Inc., Minneapolis, MN (US);
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
F16K / ;
U.S. Cl.
CPC ...
251 28 ; 91404 ; 251 77 ; 251 634 ;
Abstract
A pilot valve assembly is provided which substantially eliminates stalling in air motors. The pilot valve assembly is located on one end over an air piston such that when the air piston hits the trip rod, the trip rod compresses a trip spring which is in turn compressed until the load of the force stored in this spring is sufficient to overcome the inlet air pressurizing the opposite side of the pilot valve and the main spring which also pre-loads the pilot valve. At this point, air is allowed to pass through the open pilot valve, allowing a spool valve to switch over and reverse the direction of the motor.