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:
Jul. 21, 1998
Filed:
Apr. 14, 1997
Steven P Seaney, Glen Ellyn, IL (US);
Rita R Waller, Edelstein, IL (US);
Randall A Harlow, Brimfield, IL (US);
Robert A Lapke, Peoria, IL (US);
Joseph F Duffy, Metamora, IL (US);
James R Carlberg, Peoria, IL (US);
Joseph T Phillips, Dunlap, IL (US);
Caterpillar Inc., Peoria, IL (US);
Abstract
A check valve normally blocks fluid flow from a bore to a passage and includes a spring normally holding a ball in sealing engagement with a valve seat to form a primary metal-to-metal hard seal. Another spring normally holds a poppet in engagement with another valve seat causing an annular protuberance formed on the poppet to sealingly engage a resilient seal to provide a more positive secondary soft seat seal. The poppet is unseated from the valve seat by a stem of a piston prior to the ball being unseated from the valve seat by a guide stem of the poppet so that the soft seal is opened at essentially zero flow conditions.