Security tag with 3-ball clutch and rotation-driven release
An example electronic security tag attachable to an item includes a tag body member, a connecting member having a pin portion releasably engageable with the tag body member, the pin portion extending along a first axis. The electronic security tag further includes a locking member to lock the connecting member to the tag body member. The locking member includes a clutch mechanism movable parallel to the first axis between a first position in contact with the pin portion and corresponding to a locked state and a second position corresponding to an unlocked state. The locking member further including a rotational drive member configured to rotate and interact with a plunger member of the clutch mechanism to move the clutch mechanism from the locked state to the unlocked state.
1. An electronic security tag attachable to an item, comprising:
a tag body member;
a connecting member having a pin portion releasably engageable with the tag body member, the pin portion extending along a first axis;
a locking member to lock the connecting member to the tag body member, wherein the locking member includes a clutch mechanism movable parallel to the first axis between a first position in contact with the pin portion and corresponding to a locked state and a second position corresponding to an unlocked state, wherein the clutch mechanism includes a plunger member comprising a plurality of first protrusions; and
a rotational drive member comprising a plurality of second protrusions configured to interoperate with the plurality of first protrusions, wherein the rotational drive member is rotatable about a rotation axis that is parallel to the first axis and in a plane perpendicular to the first axis to move the plunger member in a direction parallel to the first axis.
2. The electronic security tag of claim 1 , wherein the plunger member is configured to movably hold at least three balls of the clutch mechanism, wherein the at least three balls are arranged in a circular manner to receive the pin portion of the connecting member and engage the pin portion in the locked state to resist movement away from the tag body member.
3. The electronic security tag of claim 2 , wherein the plunger member comprises a plunger member body having at least three capture recesses therewithin, wherein the at least three capture recesses are circumferentially spaced apart.
4. The electronic security tag of claim 2 , further comprising a biasing member in contact with the plunger member and having a biasing force that biases the plunger member towards a top end of a bell shaped member of the clutch mechanism, which corresponds to the locked state.
5. The electronic security tag of claim 2 , wherein the clutch mechanism further comprises a bell-shaped member having a closed top end and an inner surface defining an open bottom end configured to receive the at least three balls.
6. The electronic security tag of claim 2 , wherein the plurality of first protrusions have a ramp shape, the ramp shape comprising at least one angled surface portion configured to interoperate with the plurality of second protrusions.
7. The electronic security tag of claim 6 , wherein the plurality of second protrusions have a ramp shape, the ramp shape comprising at least one angled surface portion.
8. The electronic security tag of claim 2 , further comprising a housing member configured to stabilize the rotational drive member and the plunger member when the clutch mechanism is moved between the locked state and the unlocked state.
9. The electronic security tag of claim 8 , wherein the plunger member in the second position causes the pin portion to be released from the at least three balls to allow removal of the pin portion from the tag body member.
10. The electronic security tag of claim 2 , wherein the plunger member comprises at least one contact surface configured to receive a force to move the clutch mechanism from the first position to the second position.
11. An electronic security tag attachable to an item, comprising:
a tag body member;
a connecting member having a pin portion releasably engageable with the tag body member, the pin portion extending along a first axis;
a locking member to lock the connecting member to the tag body member, wherein the locking member includes:
a clutch mechanism movable parallel to the first axis between a first position in contact with the pin portion and corresponding to a locked state and a second position corresponding to an unlocked state, wherein the clutch mechanism includes:
a plunger member configured to movably hold at least three balls of the clutch mechanism, wherein the at least three balls are arranged in a circular manner to receive the pin portion of the connecting member and engage the pin portion in the locked state to resist movement of the pin portion away from the tag body member, the plunger member further comprising a plurality of first protrusions; and
a rotational drive member configured to receive a force to rotate the rotational drive member in a plane perpendicular to the first axis to move the plunger member in a direction parallel to the first axis, the rotational drive member comprising a plurality of second protrusions configured to interoperate with at least one of the plurality of first protrusions to move the clutch mechanism from the first position to the second position, wherein the force is one of:
a mechanical force on the plunger member exerted by an external device;
a pulling force exerted by a shape metal alloy (SMA) wire coupled to the rotational drive member; and
a motive force exerted by an electric motor.
12. The electronic security tag of claim 10 , wherein the force is normal to the first axis.
13. The electronic security tag of claim 1 , wherein the plunger member is formed from a non-ferromagnetic material.
14. The electronic security tag of claim 1 , further comprising:
an actuator configured to rotate the rotational drive member; and
an electrical controller configured to generate a signal to control the actuator to rotate the rotational drive member.
15. The electronic security tag of claim 14 , wherein the actuator comprises an electrical controller.
16. The electronic security tag of claim 14 , wherein the actuator comprises a magnetic induction coil.
17. The electronic security tag of claim 14 , wherein the actuator comprises an antenna and circuit that converts wireless signals to energy.
18. The electronic security tag of claim 14 , wherein the actuator comprises an electric motor driving a lead screw or gear.
19. The electronic security tag of claim 1 , wherein the tag body member and the connecting member are connected in a unitary housing.
20. The electronic security tag of claim 1 , wherein the first axis and the rotation axis are co-axial.
21. The electronic security tag of claim 1 , wherein the rotational drive member receives a force that causes rotation of the drive member, wherein the force is one of:
a mechanical force on the plunger member exerted by an external device;
a pulling force exerted by a shape metal alloy (SMA) wire coupled to the rotational drive member; or
a motive force exerted by an electric motor.