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. 29, 1977
Filed:
Aug. 23, 1976
Douglas L Cheever, Dubuque, IA (US);
Faye L Knodle, Newton, IA (US);
A. Y. McDonald Mfg. Co., Dubuque, IA (US);
Abstract
A spring loaded, tamperproof plug valve such as a pressure gas stop has the rotatable valve plug resiliently retained against removal from the valve body by two stacked, slit, frustoconical, transversely arched spring washers that have teeth which make a one-way tight friction fit on a projecting end portion of the valve plug, and the outer peripheral portion of the forward of the two washers bears on a recessed planar area of the valve body which is surrounded by a continuous boss so a prying tool cannot be inserted beneath either washer. A self-threading sheet metal nut forms a thread in a reduced extremity of the valve plug and has a concentric integral skirt which bears on the teeth and also on the crown of the arched slit washer. The plug can be removed only by destroying the washer or the valve, either of which renders it inoperative. The nut will strip before the spring washers can be compressed enough to 'lock' the plug in the valve body.