GB2347493A

GB2347493A - Trolley security system

Info

Publication number: GB2347493A
Application number: GB9904767A
Authority: GB
Inventors: Ray Higgs
Original assignee: Individual
Current assignee: Individual
Priority date: 1999-03-02
Filing date: 1999-03-02
Publication date: 2000-09-06
Also published as: GB9904767D0

Abstract

The invention provides a system for detecting the movement of an item (12) through a zone (10), comprising one or more beam generating devices (2) for producing a beam (6) in the zone (10), one or more signal detecting devices (3), one or more reflective targets (11) securable to the item (12) for reflecting the beam (6) back to the signal detecting device (3) to produce a reflective signal upon movement of the reflective targets (11) across the beam (6), and an alarm (5) activatable by the signal detecting device (3) upon detection of the reflective signal. The targets may be on one or both sides of the item, and movement of the item in a specific direction may be detected. An infra-red beam may be used.

Description

Improvements in or relating to trolley security systems The invention relates to a system for detecting unauthorised removal of property from premises, and thus increases operational security. More specifically, it relates to a system for detecting the unauthorised removal of goods from trade establishments, such as retail outlets.

In large retail outlets, such as warehouse type stores, it has been noticed that some dishonest customers have been loading shopping trolleys with merchandise and taking the trolleys out of the store via the entrance, thus by-passing the point-of-sale cash registers. Stock is generally protected by Electronic Article Surveillance (EAS) Tagging Systems, which are relatively expensive and are thus usually located only at the exit to the stores. In addition, tagged items placed within metal shopping trolleys can be shielded from detection, due to the Faraday cage effect, thus affecting the reliability of the detection system.

It is the aim of the present invention to obviate, or reduce, the above mentioned problem by providing a cost effective solution, separate to that of the EAS Tagging Systems.

Accordingly, the invention provides a system for detecting the movement of an item through a zone, comprising one or more beam generating devices for producing a beam in the zone, one or more signal detecting devices, one or more reflective targets securable to the item for reflecting the beam back to the signal detecting device to produce a reflected signal upon movement of the reflective targets across the beam, and an alarm activatable by the signal detecting device upon detection of the reflected signal.

Preferably the item is a shopping trolley.

Preferably the beam generating and signal detecting devices are located at the entrance to a premises. In particular, the alarm is activated only upon movement of the item in a direction out of the premises through the entrance.

In one embodiment of the invention, the reflective target is attached only to one side of the item and the beam generating and signal detecting devices are located at one side only of the zone.

In another embodiment of the invention, the reflective target comprises at least three discrete reflective surfaces secured to the item, spaced apart at dissimilar intervals.

In another embodiment still, the reflective targets are attached to two opposing sides of the item.

Specifically, a reflective target comprising a single discrete reflective surface is located on one side of the item, and a reflective target comprising a number of discrete reflective surfaces is located on the opposing side of the item.

In one particular embodiment the detectors are located on either side of the entrance to the premises.

In another embodiment still, the signal detecting device is activated only by reflections from the reflective target.

Preferably, the alarm comprises audible and/or visual warnings.

Advantageously, the beam generating device and the signal detecting device are combined into a single unit.

Preferably, the beam comprises infra-red waveforms.

The following is a description of specific embodiments of the invention, by way of example only, reference being made to the accompanying drawings in which : Figure 1 is a schematic representation of a beam generating device, a signal detecting device, and a alarm device; Figure 2 is a diagrammatic representation an embodiment of the trolley surveillance system of the present invention inoperation at the entrance to a retail outlet; Figure 3 is an illustration of a particular reflector/detector configuration, under various trolley entry (A and B) and exit (C and E) situations; Figure 4 is a logic table illustrating the various trolley entry/exit situations when either one detector, or two detectors located on either side of the entrance to the retail outlet, are used with the reflector configuration shown in Figure 3.

The system of the present invention consists of a detector device, typically mounted at a fixed location, such as the entrance to a retail premises, and a reflector mounted to an item to be monitored, in this case a shopping trolley.

As shown in Figure 1, the trolley detector 1 comprises a beam generator 2, a signal receiver or detector 3, a power supply 4, and an alarm system 5. These various devices can of course be combined into a single housing with a common power source.

The beam generator 2 produces a continuous beam 6 which is directed over a security zone 10, e. g. the entrance to a premises as shown in Figure 2.

Typically, the security zone extends up to 10 metres from the trolley detector 1, and is dependent upon the actual beam generator 2, and signal detector 3 used.

This beam 6 is preferably an infra-red beam, although other waveforms, such as radio frequency waveforms, may alternatively be used.

Figure 2 shows shopping trolleys 12, to which are attached reflectors 11. The reflector 11 is attached to the trolley 12 by security nuts to prevent, or at least hinder, unauthorised removal. The reflector 11 comprises prismatic lenses formed in a transparent synthetic resin, sealed and backed with a pre-coated pressure sensitive adhesive which is protected by a removable plastic liner e. g. Scotchlite.

As also shown in Figure 2, the trolley detector 1 is fitted into a steel bumper post housing 13, which can be used to protect existing EAS Tagging System antennae. The bumper is preferably located on one side of an entrance to a store.

Ordinarily, the beam 6 can be broken without the alarm system 5 being activated e. g. by persons walking through the beam. However, if the reflector 11 cuts the beam 6, the beam 6 will be reflected back towards the signal receiver 3, which in turn will activate the alarm system 5. The alarm system 5 may be an audible and/or visual warning of any desired form e. g. a voice alarm, beeper, flashing light, Xenon beacon, etc.

It is important that the system comprises so called "retro-reflective"devices and beams. Thus, the system will only be actuated by reflections from the reflector 11 and not by reflections from, for example, the trolley 12, as would be the case with so called "passive reflective"systems.

For the signal receiver 3 to activate the alarm system 5, it must receive at least one pixel of the reflected beam 6. Thus, it is advantageous to size the reflector 11 such that it is not easily shrouded. For example, if the reflector 11 is manufactured to be wider than the width of a human leg, it can not be easily concealed by someone walking along side the trolley.

In one specific embodiment, the detector 1 is placed only on one side of the entrance and the reflector 11 is attached only to one side of the trolley 12 such that, when the trolley is pushed in the conventional manner (ie. facing forward) through the security zone 10 on entering the retail outlet, the reflector 11 faces away from the detector 1 so that it does not reflect the beam 6 to activate the alarm 5. However, if someone attempts to leave the premises via the entrance, again pushing the trolley in a conventional manner, the reflector 11 will now face the detector 1 and so will reflect the beam 6 and activate the alarm 5.

This is the simplest solution and is effective in a majority of situations. However, problems arise with this configuration if the trolley is pushed backwards (or pulled by the handle) out of the exit. Under these circumstances, the reflector is still positioned on the wrong side, with respect to the detector, and thus the detector will not receive a reflected signal and the alarm will not be activated.

In another specific embodiment, the reflector 11 comprises at least three discrete reflective surfaces, secured to one side of the trolley, spaced apart at dissimilar intervals. Again, when the reflector 11 crosses the security zone 10, the beam 6 is reflected back to the signal detector/receiver 3. However, in this case, the reflected beam will comprise a number of corresponding dissimilarly spaced discrete signals, from which can be determined the direction of motion of the trolley 12. This spacing will primarily be one of time increment, i. e. the interval between each of the discrete signals and not their respective durations. For example, dependent upon the actual arrangement of the discrete reflective surface, one discrete signal followed, one second later, by two successive discrete signals, the time between these two signals being half a second, may indicate that the trolley is moving forwards. Correspondingly, two successive discrete signals, spaced apart by half a second, followed one second later, by one discrete signal would indicate the trolley is moving backwards.

It is of course, due to the number of variables, which includes for example the velocity of the trolley, the relative difference between the time intervals, and not the actual time intervals themselves, which would be used to determine the direction of motion of the trolley 12. A Logic Timer Circuit (not shown) is then used to calculate the direction of movement.

This arrangement of three reflectors on one side of the trolley and one detector on one side of the entrance will therefore detect the backwards movement of the trolley through the entrance. However, it will not detect the trolley being pushed forwards, in a normal manner, out of the entrance of the store, as the reflectors would be positioned on the wrong side of the trolley and be facing away from the detector.

Thus, the optimum system will be able to distinguish between the four situations A, B, C and E, where A and B represent a trolley entering the store, being pushed forwards by the handle (as normal) and a trolley being pulled by the handle, and C and E represent a trolley exiting the store, being pushed forwards by the handle and being pulled by the handle, respectively. The alarm should only be activated in situations C and E.

A simple way to achieve this is to use different configurations of the reflector on each side of the trolley, for example one side having three (or more) dissimilarly spaced reflectors and the other side having a single reflector, and using two detectors each positioned on either side of the entrance.

Alternatively, the three discrete reflectors could be replaced by two discrete reflectors (not shown).

One particular reflector 11/detector 1 configuration is illustrated in Figure 3, with a corresponding logic table, in Figure 4, showing the signals received by detectors for when both a single detector D1 is used (as shown in Figure 3), and when one detector is positioned on either side of the store entrance (D1 and D2).

Figure 3 shows, for a particular reflector configuration, four situations A, B, C and E of the trolley 12 in relation to a single detector 1 (D1 of Figure 4) located only on one side of the store entrance. As mentioned above, configurations A and B are for situations upon entrance to the retail outlet, with the trolley being pushed in the conventional manner A (i. e. the handle 15 being used to push the trolley 12), and an unconventional manner B (i. e. the handle 15 being used to pull the trolley 12).

Situations C and E correspond to the condition on exit from the retail outlet, where the trolley is being pushed in a conventional manner C, and unconventional manner E. The direction of motion of the trolleys 12 are indicated by the arrows.

The reflector configuration shown in Figure 3 utilises reflectors on both sides of the trolley 12; a single reflector 11 on one side of the trolley 12, and three discrete reflectors, lla, llb and llc, spaced apart at dissimilar intervals on the other side of the trolley 12.

Thus, in situation A, as the trolley is pushed passed the detector 1, the detector 1 initially receives a reflected signal from the first reflector lla, followed by a relatively long gap L until it receives a second reflected signal from reflector llb. The third reflected signal is reflected from llc. However, the gap S, between the second and third reflected signals, is shorter in duration than L. In situation B however, the detector only receives a single signal 0.

Accordingly, the various signals received by the single detector D1, in the four situations A, B, C and E, are summarised in Figure 4. As can be seen by Figure 4 row D1, on the assumption that, on entrance to the retail outlet the trolley 12 is most likely always to be pushed in the conventional manner (i. e. ignore situation B), the Logic Circuit will be able to distinguish between the situations A, C and E due to the different signals produced under each of these situations, and thus can be configured to activate the alarm in situations C and E when the customer is attempting to leave the store via the entrance.

However, if situation B cannot be ignored, then using this particular reflector configuration, detectors will be required on either side of the entrance to the retail outlet. The various signals received by detectors D1 and D2 under these circumstances are shown in Figure 4. As is shown in the table, by comparing the signals received by D1 and D2, the situations A, B, C, and E are now fully distinguishable. In particular, situations A and E are distinguishable by the fact that in situation A, for example, D1 initially receives a signal from lla, and at the same time D2 also receives a signal from the reflector 11 positioned on the opposite side of the trolley 12. However, in situation E, when the detector D1 receives an initial signal from llc, D2 does not receive a corresponding signal. In fact, D2 receives a signal at a similar time to when D1 receives a signal from lla, only after D1 has received signals from llc and llb.

Thus, using the above mentioned configurations as examples, the most robust solution is provided when the reflector configuration of Figure 3 is used with a detector on each side of the entrance to the store.

However, it will be appreciated that there are numerous configurations of reflectors and detectors which can be used to achieve the desired end result, i. e. the alarm is activated whenever a trolley is moved out of the entrance to the premises.

For example, a number of detectors could be arranged on the same side of the entrance to the retail outlet, for example, two detectors side by side (not shown), and may both be fitted to the same bumper post housing 13. Thus, the direction of motion of a single reflector 11, attached to trolley 12, can be identified by the sequence in which the adjacent detectors receive reflected signals.

The system is not limited to use at entrances and with shopping trolleys. It can of course be used in any system in which it is desired to monitor movement of an item in an unauthorised direction through a given zone.

The invention thus provides an improved and cost effective system for detecting unauthorised removal of property from premises, particularly for detecting the removal of shopping trolleys through a store entrance.

Claims

Claims 1. A system for detecting the movement of an item through a zone, comprising one or more beam generating devices for producing a beam in the zone, one or more signal detecting devices, one or more reflective targets securable to the item for reflecting the beam back to the signal detecting device to produce a reflected signal upon movement of the reflective targets across the beam, and an alarm activatable by the signal detecting device upon detection of the reflected signal.
2. A system as claimed claim 1 wherein the item is a shopping trolley.
3. A system as claimed in claims 1 or 2, wherein the beam generating and signal detecting devices are located at the entrance to a premises.
4. A system as claimed in claim 3, wherein the alarm is activated only upon movement of the item in a direction out of the premises through the entrance.
5. A system as claimed any of the preceding claims, wherein the reflective target is attached only to one side of the item and the beam generating and signal detecting devices are located at one side only of the zone.
6. A system as claimed in any of the preceding claims, wherein the reflective target comprises at least three discrete reflective surfaces secured to the item, spaced apart at dissimilar intervals.
7. A system as claimed in any of the preceding claims, wherein the reflective targets are attached to two opposing sides of the item.
8. A system as claimed in claim 7, wherein a reflective target comprising a single discrete reflective surface is located on one side of the item, and a reflective target comprising a number of discrete reflective surfaces is located on the opposing side of the item.
9. A system as claimed in claim 3, wherein detectors are located on either side of the entrance to the premises.
10. A system as claimed in any of the preceding claims, wherein the signal detecting device is activated only by reflections from the reflective target.
11. A system as claimed any of the preceding claims wherein the alarm comprises audible and/or visual warnings.
12. A system as claimed in any of the preceding claims wherein the beam generating device and the signal detecting device are combined into a single unit.
13. A system as claimed in any of the preceding claims wherein the beam comprises infra-red waveforms.
14. A system as hereinbefore described and with reference to the drawings.