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:
May. 26, 1992
Filed:
May. 03, 1991
Koji Ichihashi, Saitama, JP;
Kyoji Tanaka, Saitama, JP;
Zexel Corporation, Tokyo, JP;
Abstract
There is disclosed a solenoid-operated selector valve adapted for control of hydraulic clutches such as of a tractor. The selector valve has four ports and can assume two positions. The selector valve includes a spool having an axially extending hole. A piston and a sequence valve are held in this hole. The sequence valve can relieve the pressure. The hole is in communication with the outside of the spool via first through third radially extending holes. The pressure inside one cylinder port which is normally connected with the pump port is maintained constant even when the engaged clutch is being switched to the other. This pressure is not reduced down to zero until the pressure inside the other cylinder port reaches a predetermined pressure.