Patent Publication Number: US-11640754-B2

Title: Security tag

Description:
BACKGROUND 
     This invention relates to a security tag for use in a retail environment. In particular this invention relates to a security tag including a flexible member or lanyard that can be formed into a loop to attach the security tag to an article. 
     There are a number of known systems for deterring or preventing theft of articles from a retail environment. Typically these systems include an electronic article surveillance (EAS) tag that is attached to the article or object in a retail store. While the EAS tag is activated, the tag is arranged to trigger an alarm if the tag, and therefore the article, passes between a pair of detection gates, which are typically positioned at the entrance and exit of the retail store. 
     An acousto-magnetic (AM) EAS tag includes a ferromagnetic or ferrimagnetic amorphous metal strip, which has magnetostrictive properties. Typically this amorphous metal strip will be a ferrite. The detection gates at the entrance and exit of the retail store emit periodic tonal bursts at around 58 kHz. This is the same as the resonant frequency of the amorphous metal strip or ferrite, which causes the amorphous strip to vibrate which leads to a change in its magnetisation. This change in magnetisation induces an AC voltage in a receiver antenna of the detection gate, which triggers an alarm. 
     When a customer purchases an article having one of these EAS tags attached to it, the tag is deactivated and/or removed so that the alarm is not triggered when that person leaves the retail store. Security tags that are deactivated and removed completely from the article are often referred to as hard tags and are re-usable. 
     There are a number of different ways of attaching hard tags to articles, and which one is used will typically depend on the type of article being tagged. One known type of tag includes a flexible cable or lanyard that may be formed into a loop to pass around the article or through a part of the article. These tags may be secured to bags, clothing or sports equipment for example. Typically the lanyard is threaded through a hole or gap in the article or around a part of the article, for example through the handle of a bag. The lanyard is then fully engaged with the main body of the tag and the tag is activated. Once activated, the lanyard cannot be removed from the main body of the tag and the lanyard cannot be cut without triggering an alarm. 
     It is known, however, that thieves may cut through the main body of the tag, rather than through the lanyard, to remove the tag from the article. Alternatively, with AM EAS tags, a thief may break a part of the casing of the main body of the tag to remove the amorphous metal (ferrite) strip. 
     It is an object of the present invention to provide an improved security device for deterring theft of an object from a retail space. 
     SUMMARY OF THE INVENTION 
     According to the present invention there is provided a security tag comprising:
         a main body comprising a casing having opposite first and second end walls;   an elongate flexible member for securing around an object, a first end of the flexible member being connected to the main body;   a releasable locking mechanism in the main body, the locking mechanism configured to retain a second end of the flexible member within the casing such that a part of the flexible member external to the casing forms a loop, the locking mechanism being releasable by application of a magnetic force such that the second end of the flexible member can be withdrawn from the casing; and   two electronic article surveillance (EAS) sensors housed within the casing, a first one of the sensors being proximate the first end wall of the casing and a second one of the sensors being proximate the second end wall of the casing.       

     Preferably the casing comprises a first aperture through which a first end section of the flexible member extends and a second aperture with which the locking mechanism is associated, the first aperture being disposed proximate the first end wall and the second aperture being disposed proximate the second end wall. 
     The first and second apertures are preferably provided in a side wall of the casing, the side wall extending between the first and second end walls. 
     In preferred embodiments, when the second end of the flexible member is retained in the casing by the locking mechanism, a centre of gravity of the main body lies in a plane extending substantially parallel to at least one of the first and second end walls that is disposed halfway between the first and second apertures. 
     Preferably a passage extends between the second aperture and the locking mechanism. 
     The locking mechanism may comprise grip means moveable between a gripping position in which the grip means applies a gripping force to a part of the flexible member and a released position in which the grip means does not grip the flexible member, and wherein the grip means is biased into the gripping position. Preferably the locking mechanism comprises a biasing means configured to apply a force to the grip means in a direction substantially parallel to an axis of the passage. The biasing means preferably comprises a compression spring. The grip means preferably comprises a plurality of grip members configured to move radially inwardly to grip the flexible member and to move radially outwardly to release the flexible member. 
     The locking mechanism is preferably releasable by application of a magnetic force in a direction substantially parallel to the passage. 
     Preferably the flexible member comprises a metal cord or wire. 
     The security tag may further comprise an alarm in the main body. 
     The security tag may further comprise a control member biased to extend into the passage and arranged to contact a part of the flexible member located within the passage. The control member is preferably moveable by contact with the flexible member between a first position in which a part of the control member extends a first distance into the passage and a second position in which a part of the control member extends a second distance into the passage, the second distance being less than the first distance. Preferably the security tag comprises an alarm and contact between the flexible member and the control member completes a circuit connected to the alarm, such that if the flexible member is severed the alarm is triggered. 
     In preferred embodiments the security tag further comprises a conductive element or wire housed within the casing and connected to an alarm. A first section of the conductive element is disposed proximate a first side wall of the casing and a second section of the conductive element is disposed proximate a second side wall of the casing, and the conductive element is configured such that if the conductive element is severed the alarm is triggered. 
     Preferably each of the two EAS sensors operates at a different frequency. In some preferred embodiments a first one of the EAS sensors operates at a frequency of about 58 kHz and a second one of the EAS sensors operates at a frequency of about 8.2 MHz. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention will now be further described by way of example only and with reference to the accompanying drawings, in which: 
         FIG.  1    is a side view of a security tag according to a preferred embodiment of the present invention, the security tag comprising a main body and a flexible lanyard; 
         FIG.  2    is a top view of the main body of the security tag of  FIG.  1   ; 
         FIG.  3    is a schematic internal view of the security tag of  FIG.  1    in an engaged configuration and showing, in particular, the flexible lanyard of the tag engaged with a locking mechanism of the tag; and 
         FIG.  4    is a schematic internal view of the security tag of  FIG.  1    in a disengaged or open configuration and showing, in particular, the flexible lanyard of the tag disengaged from the locking mechanism. 
     
    
    
     DETAILED DESCRIPTION 
     A security tag  10  is designed to be releasably attached to an article in a retail store. The security tag  10  includes an electronic article surveillance (EAS) sensor  12  that generates detectable signals. A suitable EAS detector (not shown) is typically located at the exit (and entrance) of the retail store. If an article with a security tag  10  attached is removed from the store and, therefore, passes the detector, the detector detects signals emitted by the EAS sensor and triggers an alarm. 
     To allow an article to leave the store without triggering the alarm, for example after purchase of the article, the security tag  10  is detached from the article. Typically the tag  10  is detached at the point of sale of the article by a suitable detacher system (not shown). 
     A security tag  10  according to an embodiment of the present invention comprises a main body  14  and attachment means  16 . The attachment means comprises an elongate flexible member  18 . The flexible member  18  is configured to form a loop through or around part of an article. 
     The flexible member  18  extends between first and second ends  20 ,  22 . The flexible member  18  is sufficiently flexible that the flexible member  18  may be bent or curved or formed into a loop  24 . The flexible member  18  may be in the form of a lanyard or cable. The flexible member  18  may be a metal cord or wire, and the flexible member may be braided. 
     In this embodiment the first end  20  of the flexible member  18  is fixedly or permanently attached to the main body  14  such that the first end  20  does not move with respect to the main body  14 . 
     The main body  14  comprises a substantially cuboidal housing or casing  26 . The casing comprises first and second end walls  28 ,  30 , first and second side walls  32 ,  34 , and third and fourth side walls  36 ,  38 . In use, the tag  10  will typically be oriented such that the third side wall  36  is a top wall of the main body  14  and the fourth side wall  38  is a bottom wall of the main body  14 . In this embodiment a distance between the first and second end walls  28 ,  30  is greater than a distance between the third and fourth side walls  36 ,  38 . A line extending between the first and second end walls  28 ,  30  defines a longitudinal axis  40  of the main body  14  of the tag  10 . A line extending between the third and fourth side walls  36 ,  38  defines a transverse axis  42  of the main body  14  of the tag  10 , the transverse axis  42  extending perpendicular to the longitudinal axis  40 . 
     The casing  26  surrounds and defines an internal volume  44  of the main body  14  of the tag  10 . Within the internal volume  44 , and surrounded by the casing  26 , is a locking mechanism  46  for receiving the second end  22  of the flexible member  18 , circuitry  48  including an alarm  50 , and two EAS sensors  12 . 
     One or both of the EAS sensors  12  may be an acousto-magnetic (AM) sensor. In particular, each of the sensors  12  may comprise a ferrimagnetic or ferromagnetic amorphous metal strip having magnetostrictive properties. Preferably the amorphous metal strip is a ferrite. The amorphous metal strip may have a resonant frequency of about 58 kHz. In preferred embodiments one of the EAS sensors  12  is an AM sensor and the other EAS sensor  12  is a radio frequency (RF) sensor. In these embodiments the AM sensor operates at 58 kHz and the RF sensor operates at about 8.2 MHz. In preferred embodiments each of the sensors  12  comprises an elongate strip of amorphous metal having a longitudinal axis, surrounded by a coil. 
     A first one of the sensors  12   a  is disposed within the casing  26  proximate the first end wall  28  of the casing  26 . A second one of the sensors  12   b  is disposed within the casing  26  proximate the second end wall  30  of the casing  26 . The longitudinal axis of each of the elongate strips is preferably substantially parallel to the transverse axis  42  of the main body  14  of the tag  10 . 
     The first end  20  of the flexible member  18  is secured to the main body  14  within the internal volume  44  of the main body  14  proximate the first sensor  12   a  and proximate the first end wall  28 . The flexible member  18  extends through a first aperture  52  in the third side wall  36  or top wall of the casing  26 , proximate the first end wall  28 . 
     The top wall  36  includes a second aperture  54  disposed proximate the second end wall  30 . The second aperture  54  is sized to receive the second end  22  of the flexible member  18 . The second aperture  54  may have a larger diameter than the first aperture  52 . The locking mechanism  46  within the internal volume  44  of the main body  14  is associated with the second aperture  54  and is arranged to receive the second end  22  of the flexible member  18  when the second end  22  of the flexible member  18  is inserted through the second aperture  54 . 
     The locking mechanism  46  is disposed within the internal volume  44  of the casing  26  proximate the fourth side wall  38  or bottom wall of the casing  26 . In this embodiment a part of the locking mechanism  46  is disposed in a protrusion  56  formed in the bottom wall  38  of the casing  26 . A passage or bore  58  extends from the second aperture  54  to the locking mechanism  46  so that the locking mechanism  46  is disposed at an end of the passage  58  furthest from the second aperture  54 . As such, an axis of the passage  58  is substantially parallel to the transverse axis  42  of the main body  14  of the tag  10 . The passage  58  is sized to receive the flexible member  18 , and in particular a second end section of the flexible member  18 . As such, a diameter of the passage  58  is slightly larger than an external diameter of the flexible member  18 . The locking mechanism  46  is configured to automatically grip and retain the second end section of the flexible member  18  such that the second end  22  of the flexible member  18  cannot be withdrawn from the main body  14  of the tag  10  until the locking mechanism  46  is released. 
     In a released configuration the locking mechanism  46  does not apply a gripping force to the flexible member  18  allowing the second end  22  of the flexible member  18  to be withdrawn from the passage  58 . 
     The locking mechanism  46  may be of any suitable configuration known in the prior art. In this embodiment, the locking mechanism  46  includes a plurality of balls or spheres retained in a cup element. When the flexible member  18  is inserted into the passage  58 , the second end  22  of the flexible member  18  extends between the balls so that the balls surround the second end section of the flexible member  18 , as illustrated in  FIG.  3   . The locking mechanism  46  is biased into a first, gripping position or locked configuration in which the balls are urged towards the flexible member  18  by suitable biasing means. In this embodiment the biasing means comprises a biasing member in the form of a spring. The spring urges the balls into a tapered section of the cup element. 
     The locking mechanism  46  is released by application of a magnetic force to the locking mechanism  46 . In this embodiment the magnetic force is applied by means of a magnet (not shown) placed against the protrusion  56  in the bottom wall  38  of the casing  26 . The magnetic force causes the balls to move in a direction out of the tapered section of the cup element against the biasing force of the spring. In this position, the balls no longer grip the end section of the flexible member  18 , allowing the second end  22  of the flexible member  18  to be withdrawn, as illustrated in  FIG.  4   . In this embodiment, therefore, the locking mechanism  46  is released by application of a magnetic force in a direction substantially parallel to an axis of the passage  58 . 
     In use, therefore, the flexible member  18  is passed around or threaded through a part of an article and the second end  22  of the flexible member  18  is inserted into the second aperture  54  and into the passage  58 , such that a bend or loop  24  is formed in the flexible member  18  between the first end  20  of the flexible member  18  and the second aperture  54 . The security tag  10  is then in an engaged configuration. 
     When it is desired to remove the tag  10  from the article, the locking mechanism  46  is released by applying a magnetic force to the locking mechanism  46 . The second end  22  of the flexible member  18  can then be withdrawn from the passage  58 . The security tag  10  is then in a disengaged or open configuration. 
     As shown most clearly in  FIG.  4   , the first EAS sensor  12   a  is disposed between the first end  20  of the flexible member  18  and the first end wall  28  of the casing  26 . The second EAS sensor  12   b  is disposed between the passage  58  (and locking mechanism  46 ) and the second end wall  30  of the casing  26 . 
     An advantageous feature of the security tag  10  is that, when the security tag  10  is in the engaged configuration, the centre of gravity of the main body  14  of the tag  10  lies in a plane extending parallel to the transverse axis  42  of the tag  10  that is disposed substantially halfway between the first and second apertures  52 ,  54  in a direction parallel to the longitudinal axis  40  of the tag  10 . In this way, where possible, when the tag  10  is secured to an article, and is in an engaged configuration, the tag  10  hangs substantially vertically. 
     In addition to the EAS sensors  12 , the security tag  10  includes an alarm  50  which is triggered if a person attempts to cut or remove the tag  10  from an article. The alarm  50  is preferably an audible alarm. The alarm  50  may also comprise a light emitter. The alarm  50  is activated when the second end  22  of the flexible member  18  is inserted into the passage  58  and held by the locking mechanism  46 . The alarm  50  is then triggered if the flexible member  18  is cut or otherwise severed, for example if a person attempts to cut the flexible member  18  to remove the tag  10  from an article. 
     In these embodiments the security tag  10  comprises a control member or button  60 . The control member  60  is connected to the circuitry  48  within the tag  10  which, in turn, is connected to the alarm  50 . The control member  60  is disposed in the internal volume  44  of the casing  26  and is associated with the passage  58  such that, when the flexible member  18  is disposed through the passage  58 , a part of the flexible member  18  within the passage  58  contacts the control member  60 . 
     The control member  60  is moveable between a first position in which a part of the control member  60  extends a first distance into the passage  58  (shown in  FIG.  4   ) and a second position in which a part of the control member  60  extends a second distance into the passage  58  (shown in  FIG.  3   ), the second distance being less than the first distance. The control member  60  is biased into the first position. The control member  60  is moved into and retained in the second position by means of contact with the flexible member  18  in the passage  58 . 
     While the flexible member  18  is disposed in the passage  58 , the control member  60  is held in the second position by the flexible member  18  and the alarm  50  is activated. A section of the flexible member  18 , extending between the control member  60  and the first end  20  of the flexible member  18 , completes a circuit that includes the alarm  50 . If the flexible member  18  is severed in this section, which includes the loop  24  around or through the article, the alarm  50  is triggered. Upon removal or withdrawal of the flexible member  18  from the passage  58 , the flexible member  18  no longer contacts the control member  60  and the control member  60  automatically returns to the first position. With the control member  60  in the first position the alarm  50  is not activated. 
     The circuitry  48  further comprises a wire  62  or other conductive track or path that extends from or is connected to the first end  20  of the flexible member  18 . This wire  62  is part of the circuit including the control member  60  and the alarm  50  described above. The wire  62  follows a circuitous path through a central region of the internal volume  44  of the main body  14  of the tag  10 . In particular, a first section  62   a  of the wire  62  extends from the first end  20  of the flexible member  18  proximate the top wall  36  of the casing  26  towards the bottom wall  38  of the casing  26 . A second section  62   b  of the wire  62  extends substantially parallel to and proximate the bottom wall  38  of the casing  26 . This second section  62   b  extends towards the locking mechanism  46  and the passage  58 . A third section  62   c  of the wire  62  extends from a region proximate the bottom wall  38  of the casing  26  towards the top wall  36  of the casing  26 . The third section  62   c  of the wire  62  is disposed adjacent the passage  58  and locking mechanism  46 . A fourth section  62   d  of the wire  62  extends substantially parallel to and proximate the top wall  36  of the casing  26 . This fourth section  62   d  extends back towards the first end  20  of the flexible member  18 . 
     In the illustrated embodiment the wire  62  follows a path around a printed circuit board  64  on which the circuitry  48  is provided. 
     Configuring the wire  62  in this way has the advantage that if someone tries to cut through the main body  14  of the tag  10  to remove the tag  10  from an article there is a high likelihood that they will cut through a section of the wire  62 . If a section of the wire  62  is cut, or otherwise broken, the alarm  50  is triggered. 
     While a preferred embodiment of a security tag of the present invention has been illustrated in the accompanying drawings and described above, it will be appreciated that further embodiments of the invention can also be contemplated without departing from the scope of the invention as defined in the appended claims.