Rotatable cylinder lock

Claim 1

A lock assembly comprising: a cylindrical housing provided with an axially extending groove on its inner peripheral wall; a rotatable plug in said housing provided with an axially extending cavity open toward the periphery thereof, said cavity registering with said groove in a normal rotary position of said plug; locking means in said cavity provided with biasing means urging same radially outwardly for engagement with said groove in said normal position, said groove and said locking means having complementary profiles provided with sloping flanks for camming said locking means generally radially inwardly upon incipient rotation of said plug from said normal position; a plurality of axially spaced tumblers in said cavity independently rotatable about generally radial axes, said plug being provided with an axially extending key slot adjacent said cavity; a key having a shank insertable into said key slot; control means on said shank effective upon full insertion thereof to place each of said tumblers in a predetermined angular position, said locking means and said tumblers being provided with complementary formations matingly confronting one another in said angular positions but preventing inward camming of said locking means in any other position of said tumblers, said control means comprising a set of first magnets on said shank, said tumblers being provided with second magnets offset from the axes thereof attractable by said first magnets, said plug forming a thin, magnetically pervious partition between said key slot and said cavity; a plurality of pins rising from said partition and forming bearing axles for said tumblers, said locking means comprising a bar paralleling said partition, said biasing means comprising a plurality of axially spaced compression springs interposed between said partition and said bar, said complementary formations comprising projections on said bar and recesses on said tumblers, said tumblers being disk-shaped and said recesses being located at the disk peripheries thereof, the axes of said tumblers lying in an axial plane of said plug perpendicular to said partition, said projections being offset from said axial plane, said groove and said bar having generally trapezoidal cross-sections with radially outwardly converging sides, the width of said cavity slightly exceeding the major base of the trapezoid of the bar whereby said bar is limitedly tiltable in said cavity, said bar being provided with lateral teeth extending from said major base on at least one side of said axial plane and bracketing said projections, said teeth being longer than said projections and being brought into contact with an adjoining cavity wall by a tilting of said bar upon an incipient rotation of said plug blocked by nonalignment of at least one projection with a recess on a confronting tumbler.