Pin tumbler lock

Claim 1

Lock mechanism of the type having a body with a bore and a lock cylinder rotatable therein out of a locked position upon insertion of a proper key into a substantially narrow keyway in the cylinder, characterized by: A. the key and keyway being of the paracentric type and the median plane of the keyway containing the axis of the bore in the lock cylinder; B. one edge of the key having bitting thereon and its other edge being straight; C. a multiplicity of magnet bits embedded in said straight edge of the key at spaced locations along its length and of such small size that no dimension thereof is substantially greater than the thickness of the key; D. said magnet bits having poles which are contiguous to said straight edge of the key and which are randomly arranged along its length with respect to polarity; E. diametrically opposite rows of radially aligning tumbler receiving apertures in the body and in the cylinder, centered on said median plane, the cylinder apertures of one row extending into the keyway from one narrow side thereof, and the diametrically opposite cylinder apertures comprising uniform diameter wells having their bottoms in the cylinder and spaced outwardly from the other naRrow side of the keyway and the straight edge of a key therein; F. pin tumbler means in said apertures; G. springs confined in the body apertures of said one row to urge the pin tumbler means therein radially inwardly toward cylinder locking positions at which portions of said pin tumbler means project into the keyway for engagement by the bitting on the key, whereby insertion of the key into the keyway effects movement of said last named pin tumbler means to cylinder releasing positions; H. the pin tumbler means in said wells being magnetized and having direct guiding engagement with the walls of their respective wells; I. springs confined in said wells to urge the magnetized pin tumblers toward cylinder locking positions engaging the bottoms of said wells; J. means to retain said last named springs properly engaged with said magnetized pin tumblers comprising spring guide and locating members fixed in the outer portions of said wells in outwardly spaced relation to said magnetized pin tumblers and having portions loosely encircling their springs; K. and said magnetized pin tumblers being arranged to register with the magnet bits in the key when the latter is in place in the keyway, and being in such polar relation to said magnet bits as to be repelled thereby to cylinder releasing positions wholly within the body.