BACKGROUND a. Field of the Invention

This invention relates to security tags. This invention relates in particular to security tags that are configured to be attached to packaging or containers having strapping. The security tags of the invention are designed to trigger an alarm when the tag is removed from the container or if the strapping is cut or removed. b. Related Art

It is known to attach security tags to objects in a retail or warehouse environment to deter or prevent theft of the objects. Typically these security tags will trigger an alarm if they are removed from the retail or warehouse premises whilst they are still attached to the object or they will trigger an alarm if someone attempts to remove the tag from the object, before the tag has been deactivated. One particular type of security tag is designed to attach to strapping that is wrapped around an object or container. The strapping is placed around the container in such a way as to prevent or deter someone opening the container and removing the contents of the container. The known security tags typically include means for detecting if the tag is removed from the container, as well as means for detecting if the strapping is cut or removed, even if the tag remains in contact with the container.

Due to this dual functionality, known security tags for attaching to strapping are typically complex and relatively expensive to manufacture. Furthermore, they can have the disadvantage that the security tag can only be removed by very strong magnets. Typically this will require the retailers to purchase a stronger magnet specifically for deactivating and detaching these security tags. It is, therefore, an object of the present invention to provide an improved security tag that overcomes problems with known security tags.

SUMMARY OF THE INVENTION

According to a first aspect of the present invention there is provided a security tag for attachment to an object, the object including a container and a strap around the container, and the security tag comprising:

a main body comprising a slot for receiving said strap, and the main body including a foot plate that, in use, locates between said strap and said container such that an abutment surface of the foot plate contacts a surface of said container;

sensing means for detecting removal of the foot plate from the surface of the container, the sensing means comprising a trigger member, the trigger member being moveable between an extended position in which a tip portion of the trigger member protrudes from the abutment surface and an engaged position in which the tip portion does not protrude from the abutment surface, the trigger member being biased in the extended position;

a locking member movable between a locked position, in which the locking member extends fully across said slot, such that in use the locking member prevents said strap being withdrawn from the slot, and an unlocked position, in which the locking member does not extend fully across said slot; and

alarm means, the alarm means being activated by movement of the locking member into the locked position and deactivated by movement of the locking member into the unlocked position and the alarm means, when activated, being triggered to emit an alarm when the trigger member moves from the engaged position to the extended position.

To allow the security tag to be easily and quickly attached to the strap, it is preferable if the main body comprises a housing and the foot plate is in a fixed position relative to the housing. The slot is defined between the foot plate and the housing. This allows the security tag to be slid easily onto the strap using one hand. To aid insertion of the foot plate under the strap the foot plate preferably comprises a tapered edge region. The tapered edge region acts to lift the strap away from the surface of the container to allow the strap to pass into the slot of the tag.

To retain the security tag in engagement with the strap the foot plate may include a retaining ridge projecting from an upper surface of the foot plate. The ridge therefore creates and defines a neck region of the slot. The locking member is preferably aligned with this neck region such that the locking member extends fully across the neck region of the slot when the locking member is in the locked position.

The foot plate preferably includes a recess for receiving the strap. This recess is located on an opposite side of the retaining ridge to the tapered edge region in embodiments of the tag in which these features are present.

To ensure that the locking member extends fully across the slot when it is in the locked position, the foot plate preferably includes an aperture for receiving part of the locking member when the locking member is in the locked position.

In some embodiments the security tag comprises a latch member. The latch member is moveable between a first, disengaged position and a second, engaged position. In the second position the latch member is engaged with the locking member to retain the locking member in the locked position. The latch member may be pivotally mounted for movement between the first and second positions.

The latch member is preferably biased in the second position. In these embodiments a force must be applied to the latch member to move the latch member to the first position against the biasing force.

The force that is applied to the latch member to move the latch member to the first position may be a magnetic force. Accordingly, the latch member may include a magnetic material. The latch member is, therefore, configured such that, in use, when a magnet is placed in proximity to a part of the security tag, the magnetic force applied to the latch member causes the latch member to move towards the first position.

The locking member of the security tag is preferably biased in the unlocked position.

In some embodiments the locking member is connected to a carriage and the carriage is mounted for movement between a first position in which the locking member is in the unlocked position and a second position in which the locking member is in the locked position. The carriage may be mounted for sliding movement between the first and second positions. In embodiments in which the locking member is biased in the unlocked position, a biasing member may be connected to the carriage to bias the carriage in the first position.

In particularly preferred embodiments the tag comprises a latch member including a detent and the locking member is connected to a carriage. One of the locking member or carriage includes a stop and the detent engages with the stop to retain the locking member in the locked position. Preferably the carriage includes the stop and the stop comprises a shoulder and a lip. The carriage may be mounted for movement between a first position in which the locking member is in the unlocked position and a second position in which the locking member is in the locked position. Furthermore, the latch member may be moveable between a first position and a second position, such that the detent engages with the stop to retain the locking member in the locked position when the latch member is in the second position and the carriage is in the second position.

To disengage the latch member from the carriage, the carriage is preferably moveable to a third position, different from the first position and the second position. When the carriage is in the third position the detent is disengaged from the stop. The third position will typically be further from the first position than the second position. Typically the security tag will be configured such that a user must apply a force to the locking member to move the locking member into the locked position. Accordingly, in preferred embodiments a button is connected to the locking member; the button being configured such that a force applied to the button moves the locking member from the unlocked position to the locked position.

Preferably the trigger member comprises an elongate rod mounted for axial movement between the extended position and the engaged position. The foot plate may include a hole for receiving a part of the trigger member. In particular the trigger member may extend through the hole when the trigger member is in the extended position. Furthermore, a tip of the trigger member may be located in the hole when the trigger member is in the engaged position. In preferred embodiments the alarm means comprises a sounder configured to emit an audible alarm when the alarm means is triggered. The alarm means may additionally or alternatively include a visual alarm such as a light emitter.

According to a second aspect of the present invention there is provided a method of alarming an object with a security tag, the object including a container and a strap around the container, and the method comprising:

placing an abutment surface of a foot plate of the security tag in contact with a surface of the container;

engaging the security tag with said strap such that said strap is received within a slot in a main body of the security tag, the foot plate being located between the strap and the container;

moving a locking member of the security tag from an unlocked position, in which the locking member does not extend fully across said slot, to a locked position, in which the locking member extends fully across said slot such that the locking member prevents said strap being withdrawn from the slot, movement of the locking member into the locked position activating alarm means of the security tag; and

moving a trigger member of the security tag from an extended position in which a tip portion of the trigger member protrudes from the abutment surface to an engaged position in which the tip portion does not protrude from the abutment surface, subsequent movement of the trigger member from the engaged position to the extended position while the alarm means is activated triggering the alarm means to emit an alarm.

The security tag is preferably engaged with the strap such that said strap passes over a retaining ridge of the foot plate and seats in a recess in the foot plate. The locking member may be retained in the locked position by means of a latch member. The latch member is moved from a first, disengaged position to a second engaged position in which the latch member is engaged with the locking member to retain the locking member in the locked position. The locking member may be connected to a carriage which is movable from a first position to a second position. The carriage is moved from the first position to the second position to cause the locking member to move from the unlocked position to the locked position. Movement of the carriage to the second position may cause a detent on the latch member to automatically engage with a stop on the carriage. Typically the carriage will be moved from the first position to the second position by depressing a button connected to the carriage.

The alarm means preferably emits an audible alarm when the alarm means is triggered.

According to a third aspect of the present invention there is provided a method of removing a security tag from an object, the object including a container and a strap around the container, and the method comprising:

moving a locking member of the security tag from a locked position, in which the locking member extends fully across a slot in a main body of the security tag, to an unlocked position, in which the locking member does not extend fully across said slot, said movement of the locking member deactivating alarm means of the security tag; withdrawing said strap from the slot; and

removing an abutment surface of a foot plate of the security tag from a surface of the container, the removal automatically causing a trigger member of the security tag to move from an engaged position in which the tip portion does not protrude from the abutment surface to an extended position in which a tip portion of the trigger member protrudes from the abutment surface.

In some embodiments the slot includes a narrower neck region and the locking member extends fully across this neck region when the locking member is in the locked position. Once the locking member has been moved to the unlocked position, the strap can then be withdrawn from the slot through the neck region.

The security tag may include a latch member that is engaged with the locking member to retain the locking member in the locked position. The latch member must, therefore, be moved from this engaged position to a disengaged position to enable the locking member to be moved to the unlocked position.

A part of the latch member preferably includes a magnetic material, and movement of the latch member from the engaged position to the disengaged position is achieved by applying a magnetic force to the latch member by placing a magnet in proximity to a part of the security tag. In particular a part of a housing or casing of the tag may be shaped or configured to enable the correct placement of the magnet to cause movement of the latch member. The locking member may be connected to a carriage including a stop. Additionally, the latch member may include a detent. With the carriage in a second position the detent may be engaged with the stop to retain the locking member in the locked position. To disengage the detent from the stop the carriage may be moveable to a third position. Movement of the carriage from the second position to the third position may be effected by applying a force to a button connected to the carriage.

In preferred embodiments the security tag is unlocked and the alarm means deactivated by simultaneously applying a force to the button to disengage the detent of the latch member from the carriage attached to the locking member and placing a magnet in proximity to a part of the security tag to move the latch member to a disengaged position.

The force on the button is subsequently removed and the carriage is moved from the third position to a first position in which the locking member is in the unlocked position. Preferably the carriage automatically moves from the third position to the first position when the force is removed from the button. Typically, the magnet will not be moved away from the security tag until after the carriage has moved to the first position.

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:

Figure 1 illustrates a security tag according to the present invention attached to a strap around a container;

Figure 2 shows a security tag according to the present invention secured to a pair of crossed straps;

Figure 3 is a first perspective view of a security tag according to a preferred embodiment of the present invention;

Figure 4 is a second perspective view of the security tag of Figure 3;

Figure 5 is a top view of the security tag of Figure 3;

Figure 6 is a side view of the security tag of Figure 3; Figure 7 is an end view of the security tag of Figure 3; Figure 8 is a cross-sectional view of the security tag along the line VIII-VIII of Figure 5, the security tag being in a deactivated configuration; Figure 9 is a cross-sectional view of the security tag showing a first stage in the activation of the security tag;

Figure 10 is a cross-sectional view of the security tag showing a second stage in the activation of the security tag;

Figure 1 1 is a cross-sectional view of the security tag showing a first stage in the de-activation of the security tag; and

Figure 12 is a cross-sectional view of the security tag showing a second stage in the de-activation of the security tag.

DETAILED DESCRIPTION

A security tag 10 according to the present invention is configured to be attached to a strap 12 surrounding a container 14. Containers 14 such as cardboard boxes may have one or more straps 12 that extend fully around the sides of the box or container 14 to prevent the box being opened and to make the container easier to handle. The strap or straps 12 are wrapped around the box or container 14 relatively tightly although it is typically possible to lift a part of the strap 12 away from an outer surface of the box by a small distance. This may allow a person to place one or more fingers under the strap 12 to hold the strap to lift the container, and/or may allow a blade to be positioned under the strap to cut the strap 12.

The security tag 10 of the present invention is securable to such a strap 12 such that a base part of the tag 10 locates between the strap 12 and the surface 16 of the container 14. The tag 10 may then be locked so that the tag 10 cannot be removed from the strap 12 without the tag 10 being unlocked. Locking the tag 10 to a strap 12 activates an alarm housed within the tag 10. Once activated, the alarm is triggered to emit an alarm if the tag 10 is lifted away from the surface 16 of the container 14. Accordingly, the tag 10 comprises a sensor or trigger that detects if the tag 10 is lifted away from the container 14 by a preset distance. The security tag 10 is configured such that it may be attached to a single strap 12 extending around a container 14 such as a box, as shown in Figure 1 , or to a pair of straps 12 at a location where the straps cross each other, as shown in Figure 2.

A preferred embodiment of such a security tag 1 10 is illustrated in Figures 3 to 8.

The security tag 1 10 comprises a main body 120 including a foot plate 122 and an upper housing 124. The foot plate 122 includes a lower, abutment surface 126 and an upper, guide surface 128. The housing 124 includes a casing 130 providing an upper surface 132 of the housing 124 and a base plate 134 providing a lower surface 136 of the housing 124.

The main body 120 is generally cuboidal and has a rear end 138 and a front, insertion end 140. Two sides 142 of the main body 120 extend between the front and rear ends 138, 140. The foot plate 122 is connected to the housing 124 at the rear end 138 of the main body 120 so that the foot plate 122 is maintained in a fixed position relative to the housing 124. The foot plate 122 is spaced apart from the housing 124 such that there is a gap between the guide surface 128 of the foot plate 122 and the base plate 134 of the housing 124. In this way a slot 144 is formed in the main body 120 at its front end 140.

A distance between the opposing guide surface 128 of the foot plate 122 and the lower surface 136 of the base plate 134 is such that a strap 12 may be inserted into the slot 144 between the foot plate 122 and the housing 124. Preferably a minimum distance between the guide surface 128 of the foot plate 122 and the lower surface 136 of the base plate 134 is sufficient to accommodate the thickness of two straps 12, such that one or two straps 12 may be positioned within the slot 144. The foot plate 122 includes a tapered front end portion 146 and a recess or groove 148 formed in the guide surface 128. The recess 148 is spaced from the tapered end portion 146 so that a retaining ridge 150 is located between the tapered end portion 146 and the recess 148. A neck region 152 of the slot 144, having the minimum distance between the guide surface 128 and the lower surface 136 of the housing 124, is formed between the ridge 150 of the foot plate 122 and the base plate 134 of the housing 124.

An aperture 154 is formed in the foot plate 122 in a location corresponding to the retaining ridge 150. The aperture 154 is formed in the guide surface 128 of the foot plate 122 and preferably extends through the full thickness of the foot plate 122 between the guide surface 128 and the abutment surface 126.

In this embodiment, a partition 156 is upstanding from the guide surface 128 of the foot plate 122 proximate a rear edge of the recess 148. In this way the partition 156 is located on an opposite side of the recess 148 to the tapered end portion 146 and retaining ridge 150. A height of the partition 156 is such that an edge of the partition 150 furthest from the guide surface 128 contacts or engages with the base plate 134 of the housing 124.

In use, the security tag 1 10 is engaged with a strap 12 such that the strap 12 enters the slot 144 and passes over the tapered end portion 146 and the retaining ridge 150 of the foot plate 122. When the security tag 1 10 is correctly engaged with the strap 12, the strap 12 locates in the recess 148 in the foot plate 122. The partition 156 prevents the strap 12 moving rearward out of the recess 148.

Between the partition 156 and a rear end of the foot plate 122 there is a hole 158 that extends fully through the thickness of the foot plate 122. Locating this hole 158 on the opposite side of the partition 156 to the recess 148 means that the hole 158 cannot be blocked by a strap 12 during use of the security tag 1 10.

The casing 130 defines an internal volume of the housing 124 and includes a top wall 131 and a side wall 133 extending around the perimeter of the top wall 131. A perimeter of the base plate 134 is connected to an edge region of the side wall 133 furthest from the top wall 131 so as to at least partially enclose the internal volume. The housing 124 contains a locking assembly 160, a latching assembly 170, a trigger assembly 180 and alarm means 190.

The locking assembly 160 and latching assembly 170 form activation means for activating and deactivating the alarm means 190. The locking assembly 160 comprises a carriage 162, a locking member 164 and a button 166. The carriage 162 is slidably mounted within the casing 130 and is moveable between a first, deactivated position; a second, activated and latched position and a third activated and unlatched position. The carriage 162 is biased in the first position by suitable biasing means (not shown in the drawings).

The locking member 164 is attached to and moveable with the carriage 162. An aperture 165 is provided in the base plate 134 and is located and sized to receive a part of the locking member 164 therethrough. The aperture 165 in the base plate 134 is aligned with the aperture 154 in the foot plate 122. Movement of the carriage 162 causes the locking member 164 to move between an unlocked position, in which the locking member 164 does not extend across the neck region 152 of the slot 144, and a locked position, in which the locking member 164 extends through the aperture 165 in the base plate 134, across the neck region 152 of the slot 144 and into the aperture 154 in the foot plate 122. Due to the connection between the locking member 164 and the carriage 162 the locking member 164 is effectively biased in the unlocked position.

In the unlocked position an end 163 of the locking member 164 may extend through the aperture 165 in the base plate 134; however, the locking member 164 does not extend fully across the neck region 152 of the slot 144. In other embodiments the locking member 164 may be arranged such that the locking member 164 does not extend through the aperture 165 in the base plate 134 until the locking member 164 is moved into the locked position. The button 166 is arranged to cooperate with the carriage 162. The button 166 transmits a force applied by a user to the carriage 162 to move the carriage 162 from the first position to the third position and from the second position to the third position. The force applied by a user to the button 166 must be sufficient to overcome the biasing force exerted on the carriage 162 by the biasing means urging the carriage 162 to the first position. In this embodiment the button 166 is in the form of a cap that is engaged with and seated at an end of the carriage 162. An opening 167 is provided in the top wall 131 of the casing 130 through which a user accesses the button 166. Depressing the button 166 through the opening 167 causes the carriage 162 to move from the first position to the third position or from the second position to the third position depending on the activation state of the security tag 1 10.

The latching assembly 170 comprises a latch member 172 moveable between a first, disengaged position and a second, engaged position. In this embodiment the latch member 172 is pivotally mounted to the casing 130. The latch member 172 includes a detent 174, located on a first side of a pivot 175, and a control arm 176 located on a second side of the pivot 175.

The detent 174 is arranged to engage with a stop 168 provided on the carriage 162 when the latch member 172 is in the second position to retain the carriage 162 in an activated position.

The latch member 172 is biased in the second position. The biasing force is applied to the control arm 176 by a suitable biasing member 178 (shown in Figures 9 to 12) that acts on the control arm 176 to rotate the latch member 172 about the pivot 175 into the second position. The biasing member 178 may be a spring, for example a compression spring, located between the control arm 176 and a part of the casing 130. It will be appreciated that the biasing member 178 or spring may be of any suitable type and configuration to apply the required biasing force to the control arm 176 and the latch member 172. The control arm 176 further comprises a magnetic material 179. The control arm 176 may be made from the magnetic material or, alternatively, a piece of magnetic material 179 may be mounted on or in the control arm 176, which is otherwise made of a non-magnetic material. The magnetic material 179 is located such that when, in use, a magnet is positioned close to or in contact with a part of the casing 130 proximate the latch member 172, a force is applied to the control arm 176 against the biasing force of the spring 178. The application of a magnetic field, therefore, counteracts the spring biasing force and causes the latch member 172 to rotate about the pivot 175 from the second position to the first position.

The security tag 1 10 further comprises sensing means in the form of the trigger assembly 180. The trigger assembly 180 includes a trigger member 182 or finger that is slidably mounted in the casing 130. The base plate 134 comprises a hole 183 that is sized to receive a part of the trigger member 182 therethrough. In this embodiment the trigger member 182 is an elongate rod and the rod is axially aligned with the hole 183 in the base plate 134. Furthermore, the hole 183 in the base plate 134 is aligned with the hole 158 in the foot plate 122. The trigger member 182 is moveable between a first, extended position and a second, engaged position. In the extended position a distal end portion 184 of the trigger member 182 extends through the hole 183 in the base plate 134 and through the hole 158 in the foot plate 122 such that a distal tip 186 of the trigger member 182 protrudes from the abutment surface 126 of the footplate 122. In the second position the tip 186 of the trigger member 182 does not protrude through the hole 158 in the foot plate 122. Typically, in the second position, the trigger member 182 will be maintained in a position such that a contact surface 188 of the trigger member 182 at its tip 186 is substantially flush with the abutment surface 126 of the foot plate 122.

The trigger member 182 is biased in the first, extended position. The biasing force is applied to the trigger member 182 by a suitable biasing member 189 (shown in Figures 9 to 12). The biasing member 189 may be a spring, for example a compression spring, located between the trigger member 182 and a part of the casing 130. It will be appreciated that the biasing member 189 or spring may be of any suitable type and configuration to apply the required biasing force to the trigger member 182. In this example a compression spring is located between a proximal end 185 of the elongate rod 182 and a part of the top wall 131 of the casing 130.

The alarm means 190 comprises a sounder 192 configured to emit an audible alarm when the alarm means 190 is triggered as described below. In this embodiment the sounder 192 is located proximate the top wall 131 of the casing 130. A plurality of holes 194 is formed in the top wall 131 proximate the sounder 192 to allow the sound to be emitted through the casing 130.

The sounder 192 is controlled by appropriate circuitry and is powered by a battery 196 within the housing 124. Preferably the battery 196 is housed in a compartment that is accessible to a user via a door or removable cover 198, so that the battery 196 may be replaced when necessary. The foot plate 122 may include an opening or cut-out 121 to provide access to the battery compartment. The operation of the security tag 1 10 will now be described with reference to Figures 8 to 12.

Figure 8 shows the security tag 1 10 in an initial deactivated configuration. In this configuration the locking member 164 is in the unlocked position and the trigger member 182 is in the extended position.

In use, a user places the security tag 1 10 onto a container 14 such that the abutment surface 126 of the foot plate 122 is in contact with a surface 16 of container 14. Contact between the surface 16 of the container 14 and the tip 186 of the trigger member 182 urges the trigger member 182 from the extended position to the engaged position, as shown in Figure 9.

The security tag 1 10 is positioned on the surface 16 of the container 14 such that a strap 12 surrounding the container 14 passes into the slot 144 over the guide surface 128 and is seated in the recess 148 in the foot plate 122. As the security tag 1 10 is slid into engagement with the strap 12, the tapered end portion 146 of the foot plate 122 acts to lift the strap 12 away from the surface 16 of the container 14, so that the foot plate 122 of the security tag 1 10 locates between the strap 12 and the container 14. The foot plate 122 is slid under the strap 12 so that the strap 12 passes over the ridge 150 and locates in the recess 148.

In embodiments in which a single strap 12 surrounds the container 14 the security tag 10, 1 10 will be positioned such that the strap 12 lies across the recess 148 and extends from each side 142 of the main body 120 (as shown in Figure 1 ). In embodiments in which two straps 12 surround the container 14, with the straps 12 extending transverse to each other, the security tag 10, 1 10 is preferably positioned such that a part of both straps 12 lies in the slot 144. In particular, the tag 10, 1 10 is positioned so that the parts of the straps 12 where they cross each other lie in the recess 148 such that both straps 12 extend from each side 142 of the main body 120 (as shown in Figure 2).

Once the strap or straps 12 has been seated in the recess 148 the tag 1 10 is locked onto the strap or straps 12 and the alarm means 190 of the security tag 1 10 is activated. A user depresses the button 166 which causes the carriage 162 of the locking assembly 160 to move in a first direction towards the base plate 134 of the housing 124. The user depresses the button 166 sufficiently far to move the carriage 162 from the first position to the third position, illustrated in Figure 9.

With the carriage 162 in the third position the latch member 172 is free to move into the engaged position under the action of the biasing member 178 connected to the control arm 176. A user then releases or removes the force applied to the button 166. Due to the biasing force acting on the carriage 162, removal of the force on the button 166 causes the carriage 162 to move in a second direction towards the first position. However, with the latch member 172 in the engaged position the stop 168 of the carriage 162 contacts the detent 174 of the latch member 172. This causes the movement of the carriage 162 to be arrested and the carriage 162 is held in the second position by the latch member 172. This is illustrated in Figure 10. When the carriage 162 is in either of the second or third positions the locking member 164 is in the locked position such that the locking member 164 extends across the slot 144 in the region between the recess 148 and the tapered end region 146. In this position the locking member 164 blocks the slot 144 and prevents the straps 12 being removed from the slot 144 through the neck region 152. The security tag 1 10 is, therefore, locked in engagement with the strap or straps 12 and in contact with the surface 16 of the container 14.

With the carriage 162 in the second position the alarm means 190 is activated. When the alarm means 190 is activated, if the trigger member 182 moves from the engaged position to the extended position this will cause the sounder 192 to emit an audible alarm. If the security tag 1 10 is lifted away from the surface 16 of the container 14, the force applied to the contact surface 188 of the trigger member 182 by the surface 16 of the container 14 will be removed or reduced. The biasing member 189 will then cause the trigger member 182 to move towards the extended position. The alarm means 190 is configured such that when the trigger member 182 protrudes from the abutment surface 126 of the foot plate 122 by a predetermined distance the alarm is triggered and an audible sound is emitted. A person may then be alerted to the unauthorised removal of the security tag 1 10 from the container 14.

To allow the security tag 1 10 to be removed from the container 14 without triggering the alarm the security tag 1 10 must be deactivated. Deactivation of the tag 1 10 is a two step process. A magnet (not shown in the drawings) is positioned close to or in contact with the casing 130 in a location proximate the control arm 176 of the latch member 172. The casing 130 may include a protrusion or raised feature 129 that indicates the location of the latch member 172 and the correct placement of the magnet. The magnetic material 179 in the control arm 176 is attracted to the magnet such that a force is applied to the control arm 176 against the biasing member 178. The magnetic force, therefore, urges the latch member 172 towards the first position. With the carriage 162 in the second position, however, the detent 174 is retained in engagement with the stop 168 on the carriage 162. In a preferred embodiment the stop 168 comprises a shoulder 169 having a lip 161 . The lip 161 is configured to retain the detent 174 in engagement with the shoulder 169 and prevents the latch member 172 moving to the first position.

To disengage the detent 174 from the stop 168, a user must depress the button 166 to move the carriage 162 from the second position to the third position. The latch member 172 is then free to move into the first position due to the force applied by the magnet. This is illustrated in Figure 1 1 .

With the latch member 172 held in the first position by the magnetic force, the user then releases the button 166. The biasing means attached to the carriage 162 urges the carriage 162 to return to the first position, as shown in Figure 12. Once the carriage 162 has moved past the second position in a direction towards the first position the magnetic force on the control arm 176 can be removed. With the carriage 162 in this position, even though the biasing member 178 urges the latch member 172 towards the second position, the detent 174 does not engage with the carriage 162 to prevent movement of the carriage 162. In this embodiment the detent 174 contacts an outer surface of the carriage 162 but still allows the carriage 162 to continue moving towards its first position. Typically, in use, the magnet will be moved away from the casing 130 once the carriage 162 has returned fully to the first position.

With the carriage 162 in the first position the alarm means 190 is deactivated. Accordingly, even if the trigger member 182 now moves to the extended position the alarm means 190 will not be triggered and the sounder 192 will not emit an audible alarm. The security tag 1 10 can, therefore, be removed from the container 14. With the carriage 162 in the first position the locking member 164 has returned to the unlocked position. The locking member 164 is, therefore, no longer blocking the neck region 152 of the slot 144 and the straps 12 can be removed from the slot 144 via the neck region 152, i.e. the security tag 1 10 can be slid away from the straps 12 to disengage the straps 12 from the slot 144. The security tag 1 10 can then be lifted away from the surface 16 of the container 14.

In some embodiments of the security tag the alarm means may comprise a light emitting element that emits light when the alarm means is triggered. The light emitting element may be, for example, a light emitting diode located in the top wall of the casing.

In the above described embodiments the latch member is pivoted and rotation about the pivot causes the latch member to move between the first and second positions. In other embodiments the latch member may be mounted in any suitable way to enable movement between the first and second positions. For example, the latch member may be mounted for translational movement between the first and second positions. Importantly, however, biasing means are connected to the latch member to urge the latch member into the second position and an external force, such as a magnetic force as described above, must be applied to the latch member to move the latch member into the first position against the force of the biasing means. The present invention, therefore, provides a security tag that overcomes problems with known security tags, that is easy to attach to a strap surrounding a container and that emits an alarm when the tag is removed or lifted away from the surface of the container. Furthermore, the present invention allows the security tag to be used with a lower strength magnetic detacher, by introducing a further button which has to be pressed to unlock and deactivate the security tag. This two step process, therefore, allows a lower strength magnet to be used, in place of the higher strength magnets required for prior art strapping security tags. Many retailers will typically have these lower strength magnets in their deactivation tool set as they will be used for other types of security tags. The retailers are not, therefore, required to purchase a separate magnetic detacher for this security tag, which helps to minimise cost to the retailer.