Fort Lock Corporation

Gale Johnson

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.

High security pin tumbler lock

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.

Growing community of inventors

Northbrook, IL, United States of America

Gale Johnson