A lock assembly, comprising:
- an outer housing having a bored cylindrical cavity;
- an intermediate cylinder having an overall diameter to slidably and rotatably fit the bored cavity of the outer housing, a longitudinally and centrally bored cylindrical cavity;
- an inner cylinder having a diameter to slidably and rotatably fit the bored cavity of the intermediate cylinder, and a centered and longitudinal key hole;
- a gear that translates a continuous rotation movement into intermittent rotary motion, comprised of slots and curved profiles;
- a gear drive pin attached to or part of the outer housing with a diameter to slidably fit the gear slot tooth profile, located to ensure engagement with the gear at all times;
- a gear drive pin attached to or part of the inner cylinder with a diameter to slidably fit the gear slot tooth profile, located to ensure engagement with the gear once there is rotation of the inner cylinder and misalignment between the inner cylinder locking pin bores and intermediate cylinder locking pin bores;
- a cam attached to or part of the inner cylinder that is concentrically aligned with the inner cylinder with a diameter to slidably and rotatably fit the gear curved tooth profile with a recess in the cam around the gear drive pin to allow for movement of the gear slot tooth around the gear drive pin;
- a provision to rotatably fit the rotational axis of the gear to the rear end of the intermediate cylinder positioned to ensure the curved profiles of the gear rotatably fit the cam;
- a plurality of locking pin bores extending radially from the center of the key-hole of the inner cylinder through the top of the key hole and continuing through the intermediate cylinder and through all or part of the outer housing;
- a number of locking pins of minimum practical lengths that slidably fit each of the locking pin bores;
- a single locking pin for each of the plurality of locking pin bores of varying lengths that slidably fit each of the plurality of locking pin bores and that do not extend outside the intermediate cylinder;
- a single locking pin for each of the plurality of locking pin bores of necessary length to allow space above it within its locking pin bore which locking pin slidably fits its locking pin bore and straddles the boundary between the outer surface of the intermediate cylinder and the surface of the bore in the outer housing, this being the primary means of locking the intermediate cylinder from rotating within the outer housing;
- a compression spring for each of the plurality of locking pin bores of a diameter to slidably fit each of the locking pin bores holding the stacks of locking pins in their locking positions;
- a flat-bladed key having a body of a cross-section that matches and is slidably fitting into the key hole cavity of the inner cylinder and having a body length to match the length of the key hole cavity of the inner cylinder, provided with a plurality of ramped notches on its top edge of the same number and spacing to match and meet with the bottom ends of the plurality of the bottom most locking pins within the locking pin bores, said ramped notches being machined to depths that cause all of the stacks of the locking pins to be raised to such a level that the junction between a pair of the pins that normally resides within the confines of the inner cylinder for each of the plurality of locking pin bores coincides with the boundary between the outer surface of the inner cylinder and the surface of the bore in the intermediate cylinder, and also that the junction between a pair of the locking pins that normally resides within the confines of the intermediate cylinder for each of the plurality of locking pin bores coincides with the boundary between the outer surface of the intermediate cylinder and the surface of the first bore in the outer housing;
- whereby, when said key is inserted into the assembly and rotational torque is applied to it, rotation of the inner cylinder is possible and, at the same time, all of the locking pin stacks are put in an unlocking position for the intermediate cylinder relative to the outer housing, whereupon rotation of the inner cylinder will cause misalignment between the inner cylinder locking pin bores and intermediate cylinder locking pin bores and further rotation of the inner cylinder will create contact between the inner cylinder gear drive pin and gear thereby causing rotation of the intermediate cylinder to the outer housing allowing further rotation of the inner cylinder;
- and whereby, if any other object fitting to the assembly and not having correctly machined ramped notches is inserted into the assembly and turning torque is applied to it, rotation of the inner cylinder is still possible because of the maximum number of locking pins operational at that level, but rotation may occur only to the point where the inner cylinder gear drive pin contacts the gear since locking pin stacks will not all be found to be in an unlocked state at that limit of rotation.