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:
Sep. 27, 1994
Filed:
Dec. 27, 1993
Applicant:
Inventors:
Eric A Hutchison, Peoria, IL (US);
John J Krone, Dunlap, IL (US);
Assignee:
Caterpillar Inc., Peoria, IL (US);
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
F16K / ;
U.S. Cl.
CPC ...
251 3005 ; 91387 ; 13762564 ; 251 47 ;
Abstract
A displacement controlled hydraulic proportional valve has a spring retainer and a force feedback spring serially disposed between a pilot valve spool and a main valve spool in a control chamber. An arcuate convex end portion on the pilot valve spool extends into a cylindrical pocket in the spring retainer essentially defining a contact point through which force is transferred between the pilot valve spool and the retainer. The point contact minimizes side loading on the pilot valve spool due to buckling of the feedback spring to minimize tendency of the pilot valve spool to stick during operation.