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:
Jan. 05, 1988
Filed:
Jan. 16, 1987
Gale Johnson, Northbrook, IL (US);
Fort Lock Corporation, River Grove, IL (US);
Abstract
An improved, highly pick-resistant tumbler lock construction incorporates annular undercut portions on both the rotating spindle and the tumbler sleeve of the lock. The undercut portions define discontinuities along the axial bores of the spindle and the tumbler sleeve so as to provide the false feel of a shear plane when the driver pins are used to manipulate the tumbler pins in order to pick or decode the lock. 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 differently 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.