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:
Mar. 17, 1998
Filed:
Dec. 07, 1995
Robert A Doll, Glendale, WI (US);
Applied Power Inc., Butler, WI (US);
Abstract
A rotary indexing valve has an electromagnetic coil which shuttles a spoil axially. As the spool shuttles axially, it cams on axially opposed surfaces so as to rotatably index the spool. Such rotatable indexing of the spool angularly positions different sized orifices into or out of registration with one of the ports in the housing to change the cross sectional area of the flow passage between the inlet and outlet ports of the housing. One of the cam surfaces is defined by an alternating series of peaks and valleys, and the valleys are at different heights so as to change the spacing between the spool and a pole piece, which varies the inductance of the coil dependent on the angular position of the spool. The inductance of the coil can therefore be measured to provide an electrical signal indicative of the angular position of the spool.