GB2305212A

GB2305212A - Security tag device

Info

Publication number: GB2305212A
Application number: GB9518825A
Authority: GB
Inventors: Guy Dimitri Milan; Stephen Terence Dunne
Original assignee: Plescon Ltd
Current assignee: Plescon Ltd
Priority date: 1995-09-14
Filing date: 1995-09-14
Publication date: 1997-04-02
Also published as: GB9518825D0

Abstract

A security tag for use on individual articles, to actuate an alarm device if an article carrying a tag is removed from a protected location. The tag includes an article engaging member 20,21 mounted on a fob portion 10 within which is provided a coil 13 for actuating the alarm device, the member 20,21 being moveable between an open position and closed position. A detent 31,32,33 is engageable with the engaging member to secure the member in its closed position, the detent being moveable by an external magnet to a further position where the engaging member is free to move between its open and closed positions.

Description

TITLE: DEVICE The present invention relates to a device, notably to a security tag for individual articles.

BACKGROUND TO THE INVENTION: It has been proposed to mark individual articles with some sort of identification which identifies that article as the property of an individual or organisation so as to prevent un-authorised removal of that article, for example from a retail shop or other public access location at which the article is displayed. Typically, such devices comprise a tag incorporating a sender which alarms a detector if the article is removed with the tag still in place. With fabric items, such as clothing, the tag is attached by means of a pin passing through the fabric and secured in place by a catch mechanism. When it is desired to remove the article, the tag can be released by releasing the catch mechanism, usually by inserting part of the mechanism into a magnetic field, under the supervision of an authorised operator.

However, where the article is made from a material which cannot readily be pierced by the pin, such tags are not suitable and other identification means have had to be employed. Typically, such other means are based upon an adhesive label which is applied to a flat area of the article, the label carrying a sender which can be detected by a suitable sensor. However, such labels are not ideal in that they can often readily be removed by a thief. If the label is securely attached to the article, it becomes difficult to remove even when an authorised person attempts to do so, or leaves a residual adhesive area on the article when removed, which is unacceptable to a user.

In an alternative proposal, a security wire is passed through apertures in a number of articles so that they are daisy chain connected to the security wire. The ends of the wire are attached to fixed points which incorporate means which detect when the wire is cut or disconnected from the fixed point. It is thus impossible to remove one of the articles unless the detection means has been deactivated. Whilst such a means provides security for the chain of articles, it is time consuming and cumbersome to remove an article from the chain, especially where it is in the middle of the chain, for demonstration or sale purposes. Such security wire systems therefore find use predominantly with items of high value which do not require to be removed from the chain frequently and where an authorised person is available to de-activate the detection means.

The need for a simple, readily removed but secure tag system persists and no satisfactory solution has been proposed. We have devised a simple form of security tag which reduces the above problems and is capable of use on a wide range of types and sizes of individual articles.

SUMMARY OF THE INVENTION: Accordingly, the present invention provides a security tag for use on individual articles, characterised in that the tag comprises: a. Means for emitting a signal for actuating an alarm device for identifying unauthorised removal of the article from a location; and b. A fob portion, preferably carrying or adapted to carry the signal emitting means; and c. Article engaging means by which the fob portion is secured to an article, which engaging means comprises a first member having a portion which engages with the fob portion, and a second portion which can be attached to or detached from the article when the first portion is in an non operative position with respect to the fob portion, but which cannot be detached from the article when the first portion is in an operative position with respect to the fob portion; and d.Detent means carried either by the first member or the fob portion for releasibly securing the said first portion in its operative position with respect to the fob portion.

Preferably, the detent means is biassed into its operative position at which it secures the said first portion in its operative position by a spring or other bias means.

The device preferably also comprises a release means adapted to be actuated by an external means for releasing the detent means from its operative position. This may be provided by the material from which the detent means is made, as when a magnetisable detent pin is used and the external means comprises a magnet adapted to withdraw the pin against the bias of the spring from its operative position.

The signal emitting means can take a wide form of suitable devices which operate by electromagnetic, radio, acoustic, magnetic or other means. The signal emitting means can be one which is activated by an external signal and which then generates a signal from a suitable signal generating circuit within the means. Thus, the signal emitting means can be a battery powered transmitter which emits a radio signal upon receipt of a triggering radio signal from a sender located at a suitable location, say adjacent the exit from the shop or other location from which removal of the article is to be prevented.However, such devices are comparatively costly and complex and it is therefore preferred to provide the signal emitting means in the form of transponder type of device in which a signal is generated by interaction with a signal from a suitable sender to re-radiate a signal, for example by inductance coupling with the sender. Thus, it is preferred to provide the signal generating means as a coil or plurality of coils which receive a radio or other signal from a sender to induce the emission of a signal from the coil(s) which can then be detected. For convenience, the invention will be described hereinafter in terms of a coil adapted to receive a radio frequency signal and to reradiate an induced electromagnetic signal.

Many forms of such devices are known and may be used in the present invention. However, it is preferred to use a coil aerial mounted on or in a plastic or other rigid or flexible support, notably one having an adhesive backing which is applied to a flat area of the fob portion of the device as if it were a label. In a particularly preferred embodiment the coil is housed in a rigid plastic disc or plate which is a sliding fit in suitable mounting grooves within the fob portion so that different forms and numbers of coils can be inserted into a standard design of fob portion according to the nature and strength of the signal which is used to activate the coil transponder.

The signal emitted from the coil(s) is received by any suitable receiver and can be used to actuate a siren or other audible and/or visible alarm means to show when the article carrying the security tag of the invention has been transported to within range of the sender/sensor, which can be located at any suitable location, for example close to an exit from the premises at which the article is located. Thus, the security tag can be applied to an article in a shop and used to alert staff to the theft of that article. However, the coil(s) could be inductively coupled with a sender/sensor at the position at which the article is located so that no alarm is sounded when the article carrying the security tag remains in that required position. When the article is moved, the inductance coupling is altered and the sensor is then actuated to operate an alarm.In this case, the article does not have to be moved for a great distance and the alarm is sounded promptly when the article is moved and not delayed until the article is transported into range of a sender/sensor, which may be some distance from the initial location of the article. However, for convenience, the invention will be described hereinafter in terms of a sender/sensor located some distance from the article which is actuated when the article is transported to within range of the signal transmitted from the sender of the sensor.

The fob portion of the device serves to support the signal emitting means. Preferably, the fob portion comprises a box like member having a removable lid, so as to provide a housing for the operating parts of the article engaging means and within which the "labels" carrying the coil(s) can be mounted so as to be protected against damage or tampering. However, the fob portion may also be a substantially flat member having the "label" carrying the coil(s) applied to one face thereof and protected by a plastics overlay or laminate. For convenience, the invention will be described hereinafter in terms of a generally square, triangular, oval, teardrop or round boxlike housing.

The fob portion can be made from any suitable material.

However, since radio or electromagnetic signals must reach the coil(s) and be emitted from the coil(s) through a wall of the fob portion, it is necessary to make at least that wall, and preferably the whole of the fob portion, from a signal transparent material. Thus, it will be preferred to form the fob portion from a moulded, cast or machined structural plastic, notably from an ABS, polyamide, polycarbonate or other engineering resin.

The fob portion is provided with the article engaging means by which the fob is attached to the article. This article engaging means is provided by a member having second portion which can be removably attached to the article and a first portion carried by the fob portion whose movement with respect to the fob portion can be controlled by the detent means. The article engaging portion is preferably in the form of a hook or loop which engages with a suitable component on the article. Many articles incorporate rings or the like for the attachment of carrying straps and the hook member can be engaged with such a ring. Alternatively, the article may have an element of its construction which provides a bar or the like to which the loop or hook member can engage.Thus, many power drills or other tools incorporate a ring to receive a chuck key or an attachment and the hook member can engage that ring; or a spectacle frame has a nose bridge or side arms with which the hook or loop member can engage; in other devices, such as dictation handsets or cameras, the casing of the device incorporates a strut spanning a recess in a corner of the casing to provide a post about which a carrying handle can be threaded and the hook member can engage that post. Other forms of structure with which the hook or loop member can engage can be used as required by the structure of the article.

For convenience, the invention will be described hereinafter in terms of a bar or post carried by the article.

The article engaging member can take the form of a hook or loop which engages the post on the article. Such engagement can be achieved by passing the post through the open jaw of the hook and subsequently closing the jaw to trap the post. Alternatively, the hook can be in the form of a bolt member which acts across the open mouth of a recess formed in the wall of the fob portion of the device. In another variation, the hook can be formed as a rotating member which co-operates with a recess or other member on the fob portion of the device to pivot or rotate between a position at which it traps or releases the post on the article.The use of a hook shaped member to attach the fob portion to the article is particularly preferred since it provides a simple linear action as described below and the action can be adjusted to accommodate posts of different sizes making the device of the invention suitable for use on a range of types and sizes of article.

For convenience therefore, the invention will be described hereinafter in terms of a hook member as the portion which engages the article.

The hook member carries the first portion which engages the fob portion and is acted upon by the detent means to secure the hook member to the fob portion. This first portion can take any suitable form, for example a pivot pin where the hook member is provided by two co-operating rotating split discs. However, it is particularly preferred to provide this second portion as a shank extending axially from the hook member, which shank is preferably journalled for axial movement in a bore or guide in the body of the fob portion of the device. This allows the hook member to be moved linearly towards or away from a co-operating face of the fob portion of the device and thus provides a simple means for varying the size of the loop formed by the closed jaw of the hook and for varying the gap provided by the open jaw of the hook.

Preferably, the free end of the hook member engages in a second bore in the body of the fob portion of the device so that, when in the closed position, the hook member forms a closed loop about the post carried by article with which it engages. In the open position, the hook member is moved away from the body of the fob portion and forms an open jaw to the hook which allows the post to be detached from the hook member.

The shank of the hook member can be of squared, rounded or other cross-section. However, the use of a round cross section shank allows the shank to be rotated about its longitudinal axis and thus allows the hook member in the open position to be rotated with respect to the fob portion and thus enlarge the open jaw to the hook, facilitating detachment of the post from the hook member.

For convenience, the invention will be described hereafter in terms of a U shaped hook member having a shank member extending axially from one arm of the U.

The shank member is journalled for axial movement relative to the fob portion so that when the shank is retracted to its operative position the hook member forms a closed loop around the post carried by the article so that the security tag of the invention cannot be released from the article; and the shank can be moved axially towards its inoperative position to carry the hook member away from the body of the fob portion of the device to form an open jawed hook which allows the post to be detached from the hook through the open jaw. The dimensions of the U and the lengths of the arms and of the shank can be varied to suit the size and shape of the article upon which the device of the invention is to be secured. Thus, a variety of thicknesses and lengths of shank and U member can be used with a single size of fob portion, further enhancing the flexibility of use of the device.

The fob portion and the shank are provided with members which co-operate with one another to provide the detent means which releasibly secures the shank in its axially retracted position and thus prevents the hook from being opened. The detent means can take the form of a stud which engages a recess in the shank and thus prevents axial movement of the shank. If desired, the stud and the co-operating recess can be of a saw tooth or other configuration to permit a ratchet type action allowing the shank to be moved axially towards its retracted position but not in the reverse direction. Such a ratchet type action also allows the shank to be moved partially or wholly to its retracted position, thus closing the jaw of the hook to differing extents, thus accommodating different sizes of post on the article or different shaped articles. Alternatively, the shank can have an axial series of recesses which are engaged by a single stud to achieve different axial positions at which the shank is locked against axial movement. However, the use of a ratchet type of detent means is particularly preferred since it offers a simple and variable position locking of the shank and can be operated without the need to release the detent means when closing the jaw of the hook upon the post or the article. It will be appreciated that the fob portion can be provided with the recesses and the shank can carry the stud to engage those recesses. For convenience, the invention will be described hereinafter in terms of a stud carried by the fob portion which engages recesses carried by the shank member.

The detent means is preferably biassed towards engaging the shank, for example by means of a coil or leaf spring bearing upon the stud or toothed ratchet. This provides for automatic engagement of the stud or ratchet with the shank, facilitating operation of the device. Where the detent is in the form of a saw tooth ratchet, the spring bias allows the ratchet to move transversely with respect to the longitudinal axis of the shank and ride over the co-operating saw teeth on the shank. This allows the hook jaw to be closed without the need to repeatedly disengage the detent from the shank in separate operations.

The device of the invention provides a tag which can readily and simply be secured to an article. However, it will usually be desired to detach the tag from the article when removal of the article is required and authorised, for example when a tagged article has been purchased. It will therefore be necessary to provide some means by which the detent means can be released to allow the shank to move axially and allow the jaw of the hook to open. The release means can take the form of a key operated lock retaining the detent stud in position. However, this is cumbersome to operate and it is preferred to form at least part of the detent stud or its associated spring bias from a magnetic material and to apply a magnetic force to retract the detent stud when it is desired to release the tag from the article.

The tag device of the invention can be applied to a wide range of articles and each article can be sold or otherwise moved individually without the need to deactivate the security tags on other articles, as is the case with a security daisy chain wire arrangement. Since the tag makes use of a post or other attachment means present on the article, it is not necessary to apply adhesive labels or the like to the article or to damage the article by forcing a pin through its fabric.

DESCRIPTION OF THE DRAWINGS: A preferred form of the device of the invention will now be described by way of illustration only with respect to the accompanying drawings in which Figure 1 is an exploded sectional view of the device, Figure 2 is a plan view of the device of Figure 1, Figure 3 is a sectional view of the assembled device with the hook jaw in the open position; and Figure 4 shows the device of Figure 3 in various closed configurations.

DESCRIPTION OF THE PREFERRED EMBODIMENT: The device comprises a fob portion 1 and a co-operating shanked hook 2. The fob is in the form of a generally tear drop plan shaped hollow body 10 having a removable lid 11 and containing a hook shank housing 12 in the narrow end of the tear drop which may be formed integrally with the body 10 or may be a separate item which is welded or otherwise secured within the body 10. The lid 11 or an internal wall of the body 10 carries a rigid plastic disc or strip 13 carrying one or more coils imbedded therein which form the aerial which is to act as a transponder to emit a signal when the coil lies within the range of a radio signal transmitter.

The housing 12 is provided with an axially extended bore 14 which is to receive the shank 20 of a member having a hook shape 21 which forms the hook 2. The shank 20 of the hook 2 is provided with an axial series of saw tooth notches 22. The housing is also provided with a transverse bore 30 which intersects with bore 14. A detent pin 31 is journalled within bore 30 and is urged by spring 32 towards bore 14. Pin 31 can have a reduced diameter terminal portion 33 which engages with an inwardly directed shoulder 34 in bore 30 to limit the travel of pin 31 in bore 30. Pin 31 extends sufficiently for the portion 33 to protrude into bore 14 to engage the saw teeth notches 22 on shank 20.Preferably, the distal end of pin 31 has a series of saw tooth serrations which are substantially congruent to the saw teeth notches 22 on shank 20 so as to form a ratchet mechanism allowing the shank 20 to penetrate into the bore 14, but not to be removed from it unless pin 31 is retracted sufficiently to disengage the portion 33 from the notches 22. Pin 31 is made from a magnetic material, for example steel, so that it can be retracted by applying a magnetic field to fob portion using an external magnet.

As shown in Figures 1 and 4, the shank 20 can have several, in this case three, axially spaced notches 22 which allow the shank to be secured by pin 31 in different positions so that the loop 40 formed by the hook 21 and the co-operating face 41 of housing 12 can have different sizes, depending upon the axial position of the shank in bore 14. As shown, housing 14 preferably has a second bore 42 which receives the free end of hook 21 to form a closed loop 40 and to prevent the hook 21 from being rotated about the longitudinal axis of shank 20.

The fob portion can be made by machining or extrusion or other moulding of a polyamide or other suitable plastic and housing 12 and hook/shank 20/21 can be made from a similar plastic or from metal. Where the device is made from a suitable plastic, the device can be assembled and the components secured in place by ultrasonic, friction or other welding. Preferably, the lid 11 is a snap fit upon body 10.

The device is applied to an article by retracting pin 31 in bore 30 so as to release shank 20 for axial movement.

Hook 21 is moved away from wall 41 to form an open jaw to the hook as shown in Figure 3. The hook 21 may be rotated about the axis of shank 20 to increase the open size of the jaw if desired. The post or ring of the article is inserted through the open jaw to attached the device to the article. The jaw in then closed by moving shank 20 axially in bore 14 to the desired extent. Pin 31 moves axially in bore 30 to engage the appropriate notch 22 to secure the shank in the selected position and prevent the hook from moving relative to the fob portion 1 of the device. If desired the distal end of pin 31 can be formed with a saw tooth configuration to assist the pin to ride over the crowns of the notches as shank 20 is moved axially deeper into bore 14.

To detach the device from the article, pin 31 is retracted by applying a magnetic field to pin 31. This releases shank 20 to allow the jaw of the hook to open and to be disengaged from the post or ring of the article.

Claims

1. A security tag for use on individual articles, comprising: a) means for actuating an alarm device for identifying unauthorised removal from a protected location of an article to which the tag is connected; b) a fob portion carrying the actuating means; c) an article engaging member mounted on the fob portion and adapted to attach the fob portion to an article, which engaging member is movable between an open position where the engaging member may be attached to or detached from an article and a closed position where the engaging member, when attached to an article, cannot be detached therefrom; and d) detent means acting between the article engaging member and the fob portion, for securing the engaging member in its closed position.

2. A security tag as claimed in claim 1, wherein the engaging member has a plurality of closed positions and may be secured in any one of said closed positions by the detent means, whereby the engaging member may be set to a suitable closed position closely to engage an article.

3. A security tag as claimed in claim 1 or claim 2, wherein the detent means is releasable from its position where the engaging member is secured in its closed position.

4. A security tag as claimed in any of the preceding claims, wherein the detent means is spring-biased into a position where the detent means secures the engaging member in its, or a selected, closed position.

5. A security tag as claimed in claim 4, wherein means external to the fob portion are provided to move the detent means to a position where the engaging member is freed for movement to its open position.

6. A security tag as claimed in claim 5, wherein the detent means includes a member of a ferromagnetic material, and said external means comprises a magnet adapted to withdraw said member to a position where the engaging member is freed.

7. A security tag as claimed in any of the preceding claims, wherein the fob portion defines a substantially closed chamber within which the actuating means is furnished.

8. A security tag as claimed in any of the preceding claims, wherein the actuating means comprises a coil for inductive coupling with a radio frequency signal emitted by a transmitter, to permit detection of the coil in the region of the transmitter.

9. A security tag is claimed in any of claims 1-7 wherein the actuating means comprises at least two electromagnetic strips for inductive coupling with an electromagnetic field to permit the detection of the strips when in said field.

10. A security tag as claimed in any of the preceding claims, wherein the article engaging member comprises a hook or loop-shaped member having two arms, one of said arms being slidably mounted on the fob portion for movement between said open position where the other arm is clear of the fob portion and said closed position where the other arm is also engaged with the fob portion.

11. A security tag as claimed in claim 10, wherein said one arm of the hook or loop-shaped member is provided with ratchet teeth engageable by the detent means.

12. A security tag as claimed in claim 1 and substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.

13. A security system for protecting articles against unauthorised removal from a protected region, which system comprises a security tag as claimed in any of the preceding claims in combination with an alarm device responsive to removal of the tag away from said region and release means for said detent means to permit movement of the article engaging member to its open position and so to be detached from an article with which the system is employed.

14. A security system as claimed in claim 13, wherein the tag includes a resonant circuit and the alarm device comprises a radio frequency transmitter, a receiver responsive to resonance of said circuit caused by transmitted signals, and an alarm triggered by the receiver.

15. A security system as claimed in claim 14, wherein the release means comprises a magnet adapted to attract the detent means away from a position where the article engaging member is secured thereby.