Tamper-proof axial tumbler lock

Claim 1

A TAMPER-PROOF AXIAL TUMBLER LOCK OF THE CHARACTER DESCRIBED, AND COMPRISING A LOCK CYLINDER HAVING AN OPEN FRONT RIM FOR INSERTION OF A KEY THERETHROUGH, A FRONT ROTATABLE PART AND AN ANNULAR SLEEVE-LIKE REAR STATIONARY PART DISPOSED WITHIN SAID CYLINDER AND PRESENTING RELATIVELY SLIDABLE FACES WHICH MEET EACH OTHER ON AN INTERFACIAL PLANE NORMAL TO THE AXIS OF THE CYLINDER, AN ANNULAR SERIES OF LONGITUDINALLY EXTENDING BORES FORMED IN SAID STATIONARY PART, ARRNAGED IN CIRCUMFERENTIALLY SPACED RELATIONSHIP THEREAROUND AND NO LESS IN NUMBER THAN FOUR, A CORRESPONDING ANNULAR SERIES OF LONGITUDINALLY EXTENING BORES FORMED IN SAID ROTATABLE PART AND SIMILARLY ARRANGED THEREAROUND, SAID ROTATABLE PART BEING MOVABLE BETWEEN A POSITION WHEREIN THE RESPECTIVE BORES OF THE TWO PARTS ARE IN ALIGNMENT AND THE LOCK IS IN ITS LOCKED CONDITION AND A POSITION WHEREIN SUCH BORES ARE OUT OF ALIGNMENT AND THE LOCK IS IN ITS UNLOCKED CONDITION, A SPLIT TUMBLER FOR EACH PAIR OF ALIGNED BORES INCLUDING A DIRVER PIN SLIDABLE IN THE RESPECTIVE BORE OF THE ROTATABLE PART AND A FOLLOWER PIN SLIDABLE IN THE RESPECTIVE BORE OF THE STATIONARY PART, AND A HELICAL SPRING DISPOSED IN EACH BORE OF THE STATIONARY PART REARWARDLY OF THE ASSOCIATED FOLLOWER PIN AND SERVING NORMALLY TO URGE THE LATTER FORWARDLY, CERTAIN OF THE SPRING BEING OF SUBSTANTIALLY EQUAL SPRING RATE AND AT LEAST ONE OTHER OF THE SPRINGS HAVING A SPRING RATE OF NO LESS