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:
Nov. 30, 1999
Filed:
Nov. 19, 1998
Takashi Akimoto, Tsukuba-gun, JP;
SMC Corporation, Tokyo, JP;
Abstract
A three-position switching valve has a spool positioned in a valve hole that is moved relative to two drive chambers positioned on either end of the valve hole. Solenoid-controlled pilot valves are provided to control supplying and ejecting a pilot fluid to and from the two respective drive chambers. This spool is held at a neutral position by the provision of two piston chambers being formed adjacent to each of the drive chambers and constantly receiving pilot fluid through a channel, the piston chambers each having a smaller diameter than that of the drive chambers. Each piston chamber accommodates a piston which may slidably move so as to be urged by pilot fluid toward the spool and a linking member interposed between each of the pistons and the spool. A return spring is interposed between each of the pistons and each linking member as part of the structure holding the spools at the neutral position.