Key disengagement preventive device for magnetic tumbler cylinder locks

A magnetic tumbler lock mechanism having an outer cylinder and an inner cylinder rotatably about an axis of rotation said mechanism comprising:

• a key receiving recess, rectangular in cross section formed in said inner cylinder and adapted to receive a flat key having key magnets therein and a spline means projecting from one flat surface thereof for keying engagement with axially moveable pin means;
• a tumbler groove positioned non-axially in said outer cylinder to receive a tumbler magnet movable into locking engagement with said groove;
• a non-axially positioned tumbler magnet means mounted in said inner cylinder and adapted to move parallel to and across the face of said key from a first locked position to a second disengaged position upon insertion of said key into said key receiving recess;
• a key disengagement preventive device comprising an upper pin segment and a lower pin segment mounted in a pin hole extending through said inner cylinder and said outer cylinder;
• and,
• spacer means positioned within said tumbler groove preventing travel of said lower pin segment into said tumbler groove;
• whereby engagement of said key into a key hole moves said upper and lower pin segments outwardly so that a border surface between the upper pin segment and the lower pin segment is aligned with a shear line permitting relative rotation of said inner cylinder with respect to said outer cylinder and preventing removal of said key except upon re-alignment of said pin segments.