Electronic article surveillance tag with tamper resistant magnetic lock

Patent metadata

Field	Value
Publication number	US-9293020-B2
Application number	US-201414204669-A
Country	US
Kind code	B2
Filing date	Mar 11, 2014
Priority date	Mar 11, 2014
Publication date	Mar 22, 2016
Grant date	Mar 22, 2016

Abstract

Method for operating a magnetically controlled lock in an EAS tag ( 100 ) involves the application of a magnetic field to a plunger ( 322 ) within a housing ( 102 ) of the EAS tag. The applied magnetic field is used to cause a translational movement of the plunger in a first direction. The method can further involve causing a latch ( 320 ) to pivot about a pivot axis ( 807 ) by using the translational motion ( 1002 ) of the plunger to apply a torque ( 1004 ) to the latch. Rotation of the latch in this way causes it to move to an unlocked position which releases a locking pin ( 106 ).

First claim

I claim:

1. A magnetic lock that is resistant to defeat caused by forceful impacts, comprising:
a housing formed of a rigid material;
a shackle having a first end slidable within a first channel defined in the housing and a second end which is removable from a second channel defined in the housing which is offset from the first channel;
a locking pin disposed within the housing so as to secure the shackle to the housing;
a pin channel defined within the housing, the pin channel arranged to removably receive therein the locking pin along a channel axis so that the magnetic lock is coupleable to and decoupleable from an item at least partially by using the locking pin and shackle, where the item is to be protected by the magnetic lock;
a latch assembly disposed within the housing, the latch assembly including
a latch disposed adjacent to the pin channel, the latch pivotally mounted within the housing, the latch configured to lockingly engage the locking pin when in a first pivot position in which the magnetic lock is securely coupled to the item, and to release the locking pin in a second pivot position in which the magnetic lock is decoupleable from the item,
a plunger formed of a material responsive to an applied magnetic field, the plunger including an engagement face,
a plunger guide channel formed in the housing, the plunger guide channel arranged to facilitate translational movement of the plunger along a guide channel axis from a first position to a second position when the plunger is exposed to the applied magnetic field, and
a resilient member arranged to resiliently urge the engagement face of the plunger into contact with a base of the latch;

wherein a first torque is applied to the latch responsive to the translational movement of the plunger from the first position to the second position so as to cause the latch to rotate from a first pivot position in which the latch engages the locking pin to a second pivot position in which the latch is disengaged from the locking pin.

2. The magnetic lock according to claim 1 , wherein the latch is comprised of a material responsive to the application of a magnetic field and the latch is magnetically coupled to the plunger.

3. The magnetic lock according to claim 2 , wherein a pivot axis of the latch about which the latch pivots is offset from a center of mass of the latch, and wherein a second lateral portion of the latch on one side of the pivot axis has greater mass than a first lateral portion of the latch on an opposing side of the pivot axis.

4. A magnetic lock that is resistant to defeat caused by forceful impacts, comprising:
a housing formed of a rigid material;
a pin channel defined within the housing, the pin channel arranged to removably receive therein a locking pin along a channel axis;
a latch assembly disposed within the housing, the latch assembly including
a latch disposed adjacent to the pin channel, the latch pivotally mounted within the housing, the latch configured to lockingly engage the locking pin when in a first pivot position, and to release the locking pin in a second pivot position,
a plunger formed of material responsive to an applied magnetic field, the plunger including an engagement face,
a plunger guide channel formed in the housing, the plunger guide channel arranged to facilitate translational movement of the plunger along a guide channel axis from a first position to a second position when the plunger is exposed to the applied magnetic field, and
a resilient member arranged to resiliently urge the engagement face of the plunger into contact with a base of the latch;

wherein the latch is responsive to the translational movement of the plunger from the first position to the second position to cause the latch to move from the first pivot position to the second pivot position;
wherein the latch is comprised of a material responsive to the application of a magnetic field and the latch is magnetically coupled to the plunger;
wherein a pivot axis of the latch about which the latch pivots is offset from a center of mass of the latch, and wherein a second lateral portion of the latch on one side of the pivot axis has greater mass than a first lateral portion of the latch on an opposing side of the pivot axis; and
wherein a magnetic coupling between the engagement face and the second lateral portion is greater than the magnetic coupling between the first lateral portion and the engagement face.

5. The magnetic lock according to claim 3 , wherein a difference in magnetic coupling exerts the first torque upon the latch for causing the rotation from the first pivot position to the second pivot position.

6. The magnetic lock according to claim 3 , wherein the engagement face comprises a first portion and a second portion offset from the first portion, the first and second portion together defining a stepped surface.

7. A magnetic lock that is resistant to defeat caused by forceful impacts, comprising:
a housing formed of a rigid material;
a pin channel defined within the housing, the pin channel arranged to removably receive therein a locking pin along a channel axis;
a latch assembly disposed within the housing, the latch assembly including
a latch disposed adjacent to the pin channel, the latch pivotally mounted within the housing, the latch configured to lockingly engage the locking pin when in a first pivot position, and to release the locking pin in a second pivot position,
a plunger formed of material responsive to an applied magnetic field, the plunger including an engagement face,
a plunger guide channel formed in the housing, the plunger guide channel arranged to facilitate translational movement of the plunger along a guide channel axis from a first position to a second position when the plunger is exposed to the applied magnetic field, and
a resilient member arranged to resiliently urge the engagement face of the plunger into contact with a base of the latch;

wherein the latch is responsive to the translational movement of the plunger from the first position to the second position to cause the latch to move from the first pivot position to the second pivot position;
wherein the latch is comprised of a material responsive to the application of a magnetic field and the latch is magnetically coupled to the plunger;
wherein a pivot axis of the latch about which the latch pivots is offset from a center of mass of the latch, and wherein a second lateral portion of the latch on one side of the pivot axis has greater mass than a first lateral portion of the latch on an opposing side of the pivot axis;
wherein the engagement face comprises a first portion and a second portion offset from the first portion, the first and second portion together defining a stepped surface;
wherein the second portion of the stepped surface is in contact with a second portion of the latch base aligned with the second lateral portion.

8. The magnetic lock according to claim 7 , wherein a gap is provided between the first portion of the stepped surface and the first portion of the latch base aligned with the first lateral portion.

9. A method for operating a magnetically controlled lock in an electronic article surveillance (“EAS”) tag to prevent unauthorized unlocking caused by forceful impacts directed upon the EAS tag, comprising:
securing a first end of a mechanical coupler to a housing of the EAS tag using a locking pin disposed in a pin channel defined within the housing;
removably disposing a second end of the mechanical coupler in a channel other than the pin channel formed within the housing of the EAS tag so that the EAS tag is coupled to an item to be protected by the EAS tag;
applying a magnetic field to a plunger within the housing of

Assignees

• Nguyen Thang T
• Tyco Fire & Security Gmbh

Inventors

• Nguyen Thang T

Classifications

• G08B13/2434 Primary

  Tag housing and attachment details · CPC title

• E05B73/0017

  Anti-theft devices, e.g. tags or monitors, fixed to articles, e.g. clothes, and to be removed at the check-out of shops · CPC title

• Y10T70/413

  Padlocks · CPC title