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:
Jan. 02, 1979
Filed:
Jan. 17, 1977
Howard L Johnson, Joliet, IL (US);
Caterpillar Tractor Co., Peoria, IL (US);
Abstract
A pilot-operated spool valve including a valve body, a bore in the body, ports in the body and extending to the bore, a spool in the bore and axially shiftable therein, at least one pilot associated with an end of the spool for applying a shifting force to the spool, at least one spring in the body for applying a biasing force to the spool, and an adjustment for the biasing spring including a rotatable and axially movable member received in the body and engaging the spring, a cam surface in the form of interengaging threads on the member and the body for axially moving the member in response to rotation thereof, a rotatable actuator for rotating the member, a mount for the actuator so that the actuator can rotate only and is restrained against axial movement, and an axially extendable connection between the actuator and the member.