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. 07, 1989
Filed:
Jul. 07, 1987
Gale Johnson, Northbrook, IL (US);
Fort Lock Corporation, River Grove, IL (US);
Abstract
An improved, highly pick-resistant tumbler lock construction incorporates at least one of the rear face of the driver sleeve or the front face of the tumbler sleeve with a plurality of notches. Each notch surrounds a driver or tumbler axial bore so as to provide at the trough of the notch a false shear plane while the crest of the notch portion of the tumbler and driver sleeve forms a plane to fixedly support two relatively thin discs which form the true shear plane. The discs include annularly spaced bores corresponding to the tumbler and driver sleeve bores. Thus when attempting to pick the lock, and the driver and tumbler pins are at the notched false shear plane, the driver sleeve will not be able to turn because the pins will be caught in the lower part of the notch. Several of the driver pins and the tumbler pins are also provided with annular grooves which, in combination with the undercuts on the spindle and tumbler sleeve, accentuate the false feel effect in such a way that the false feel of the shear plane is provided at different inwardly extending positions of the pins, thereby making it extremely difficult to determine when a particular tumbler pin has been precisely positioned at the shear plane.