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:
Feb. 13, 1990
Filed:
Aug. 30, 1989
Robert Steinbach, Glendale Heights, IL (US);
Chicago Lock Company, Chicago, IL (US);
Abstract
An improved axial split pin tumbler type lock is provided. The improvement consists in providing a cylinder having a lock head formed with a square-shaped keyhole defining a front face on the lock head, and a three-part plug assembly inserted in the cylinder. One of the three-part plug assemblies consists of a cylinder head having a forward end provided with a square-shaped cut-out section formed therein, the square cut-out section radially traversing the tumbler bores formed therein. A tubular key is provided having an inner circular core, and an outer square-shaped face adapted to matingly engage within the square-shaped keyhole in the lock head and the square-shaped cut-out section in the cylindrical head portion. The square-shaped front face of the lock head includes a series of thickened face sections alternating with a series of thinner face sections. The driver tumbler positioned in the bores of the cylindrical head ride immediately beneath the square-shaped front face of the lock head such that the tumblers are at least partially shielded from manipulation by a lock pick by the thickened sections of the front face thereby to render the lock more pick resistant.