GB2073436A - Security system - Google Patents

Abstract

An apparatus for preventing the unauthorised removal of items from a secure area has at each entry or exit of the area at least one barrier 10, 16 means 12 for weighing a person approaching the barrier, means for recording the weight so obtained, the barrier allowing the person to pass therethrough after the weight has been recorded, and means for comparing a second weighing of the person on returning with the recorded weighing and indicating if the two weights do not agree to within preset limits. The apparatus may be used unidirectionally where it is desired to control the total weight within a designated area. <IMAGE>

Description

SPECIFICATION Security system This invention relates to a method and apparatus for preventing the unauthorised removal of items from a secure area.

In shops, supermarkets, libraries, and the like there is a perennial problem of losses through theft or pilfering. In order to combat this, plain clothes store detectives may be employed, or scanning systems involving cameras may be used. However practiced shoplifters soon learn to avoid these systems, and while they may cut down some casual theft, the root of the problem still remains.

The invention seeks to provide a security system in which unauthorised removal of items, e.g. shoplifting, may be eliminated entirely or at least reduced to negligible proportions.

According to the present invention there is pro vided a method which comprises designating a secure area, equiping every entry or exit to the area with weighing means and a releasable barrier, weighing a person on entry into the area, recording the weight, weighing the person on exit from the area, comparing the exit weight with the entry weight, and means for indicating if the entry and exit weights do not agree to within preset limits.

The invention also provides an apparatus for positioning at the entry or exit to a secure area which comprises at least one barrier, means for weighing a person-approaching the barrier, means for recording the weight so obtained, the barrier allowing the person to pass therethrough after the weight has been recorded, and means for comparing a second weighing of the person on returning with the - recorded weighing and indicating if the two weights do not agree to within preset limits.

Preferably, there will be two barriers one on either side of the weighing means. This facilitates the use of the apparatus either entering or leaving the secure area.

The means for weighing is preferably a relatively large rigid plate set into the floor of the exit or entry and mounted on load cells. The output from the load cells, with suitable circuitry, accurately measures the weight of a person, together with personal bags, coats, etc., standing on the platform. This informa tion may be recorded and associated with the individual, for instance on a punched or magnetical ly coded ticket which is issued to the person on entering the secure area. When that person leaves the secure area the ticket is presented to the apparatus and the person is reweighed. If the exit weight is not the same as the recorded entry weight to within preset limits, attention may be drawn to this fact by for example the sounding of an alarm.

The accuracy possible with apparatus of this type is considerable, and to prevent spurious alarms owing to natural weight changes e.g. through the loss of moisture, tolerances may be built into the system as desired. An alternative to this is to find out ex perimentallythe average loss per unit time in the environment of the secure area, programme this into the apparatus, and record time as well as weight on entry and exit making the necessary adjustment for the programmed average weight loss over the time concerned. The use of modern electronic computing apparatus, e.g. microprocessors, makes this a simple task.

According to another aspect of the invention there is provided a method of dynamic weighing which comprises digitalising the output from a weighing platform, sampling the digitalised output over a short period of time, and computing an average weight from the sample The invention will be described further, by way of example, with reference to the accompanying drawings, in which: Figure l is a diagrammatic perspective view of an apparatus according to the invention; Figure 2 is a diagrammatic side view of a platform load cell arrangement; and Figure 3 is a block diagram of a suitable electronic weight reading circuit.

Referring to the drawings, Figure 1 depicts a typical apparatus set up, for example, at each exit or entry to a secure area, for example the furs department within a department store. The apparatus is ideally situated within a corridor, but may be used in an open area provided suitable enclosing walls are provided. On approaching the entrance to the secure area a customer first meets a barrier 10 which is unlocked. After the barrier has been opened and the customer passes through, the barrier closes and locks. The customer then stands on a weighing platform 12togetherwith all his personal impedimenta such as coats and bags. The platform may be made so as to entirely fill the floor space within the apparatus. Once the customer's weight is settled, i.e. when he has stopped moving, the weight is recorded and encoded on a ticket issued by a dispenser 14.The dispenser and barriers, and optionally any side walls, may be mounted on the platform 12, so that if the customer leans on a barrier or the dispenser his weighing is not affected.

Removing the ticket from the dispenser 14 triggers the opening of the exit gate 16 allowing the customer into the secure area.

Preferably the platform is so located or shaped, e.g. by means of pot-shaped depressions, so that the customer is led to stand in one particular area, optimum for weighing as will be described more fully herein below.

After he has done his shopping the customer hands in his goods to a check point or sales assistant for packaging and leaves the secure area through the same or a different exit containing the apparatus of the invention. On leaving, the entry procedure is reversed. The customer first passes through the barrier 16 which cioses and locks behind him. At this point barrier 10 is also locked. He inserts his ticket into the dispenser/reader 14 and when his weight as recorded by the weighing platform 12 hasstablilized, his exit weight is compared to the entry weight recorded on the ticket within the reader 14. If the weights agree to within preset limits, e.g. 15 gm., the gate 10 is automatically unlocked and the customer leaves collecting his purchased goods outside the secure area.If however his exit weight differs from the recorded weight on the ticket by more than the preset limit both gates remain locked and an alarm is sounded. Astore detective may then be called to ask for a satisfactory explanation of the weight difference, the absence which would involve law enforcement agencies being called.

The apparatus of the invention may be made large enough to accommodate e.g. mothers with prams or disabled persons in wheelchairs without departing from the principle of operation. In order that natural weight changes should not cause spurious alarms, it is preferable that restaurants, toilet facilities, and the like should be located outside the secure area.

Referring now more particularly to Figure 2 a load cell and platform arrangement is shown which is especially advantageous. The rigid platform 12 is mounted on three load cells 18,20 and 22 such that two of the cells, 18 and 20, are located in line towards the centre ofthe platform and a third 22, is located towards one edge thereof. The area on which the customer stands is towards the opposite edge and is indicated at 24. Thus, in use, the cells 18, 20 are under compression and the cell 22 is under tension. By choosing the distances between the weighing area 24 and the groups of cells correctly, the load on each cell can be made roughly equal.

Since load cells have a preferred operating range outside of which they can give non-linear outputs, the system shown ensures that each cell is always loaded within its preferred operating range. The output of the three cells is summed to obtain the weight The summed output of the load cells may be processed by the circuit shown in Figure 3. The analogue signal from the load cells 18,20,22 is converted to a digital signal in an analogue/digital converter 26, and fed to the input 28 of a microprocessor 30. A central processing unit 32 is programmed to sample the input digital signal, e.g. 80 times per second, and calculated on average. It has been unexpectedly found that a sampling of, for example, about one second produces a weight reading which is consistantly reproducible without requiring the customer to stand still on the platform.Ideally sampling does not commence until about half a second after the customer has stepped onto the platform to reduce weight distorting caused by the initial impulse. Thus the circuit illustrated in Figure 3 could be used for dynamic weighing applications, that is for weighing people, cattle, vehicles or the like passing over a weighing platform without requiring them to stop or remain still.

A modification of the apparatus of the invention may be used for example at airports. In this modification the apparatus need only be unidirectional and all the passengers together with cabin luggage for an aeroplane pass through an apparatus according to the invention. The weights instead of being stored and compared, are in this totalled to give a total weight of passengers and luggage. This would then allow precise calculations as to the fuel requirements for an aircraft on a given journey, increasing the safety factor and at the same time preventing expensive underutilisation of the aircraft,-which, if its passenger load is below expectations, can take on, for example, additional freight. A similar system could be used in other locations where total weight needs to be controlled, e.g. lifts.

In order to compensate for weight changes introduced by debris being brought into and deposited on the weighing platform, a tare operation can be programmed into the apparatus so that the weighing platform is zeroed before each new weighing every time a customer enters the apparatus.

Also, the area of the weighing platform should be free from ledges, shelves, hooks and the like so that a customer cannot hang up his shopping bag and prevent it from being weighed. Ideally the weighing platform will fill the whole of the entire base of, or be integral with, a featureless booth so that everything a customer enters is necessarily weight with the customer.

As an added advantage, the apparatus could easily be adapted to include a counter thus giving the management of the concern employing the apparatus a source of statistical information, for example the total number of customers per week, or the like.

Claims (14)

1. A method for preventing the unauthorised removal of items from a secure area which comprises designating a secure area, equipping every entry or exit of the area with weighing means and a releasable barrier, weighing a person on entry into the area, recording the weight, weighing the person on exit from the area, and comparing the exit weight with the entry weight to ensure that they agree within preset limits.

2. A method as claimed in claim 1 in which a machine readable encoded ticket is issued to a person on entry and the same ticket is offered to the weighing means on exit to enable comparison of entry and exit weights to be made.

3. Aweighing apparatus which comprises at least one barrier, means for weighing a person approaching the barrier, means for recording the weight so obtained, the barrier allowing the person to passtherethrough aftertheweight has been recorded, and means for comparing a second weighing of the person on returning with the recorded weighing and indicating that the two weights do not agree within preset limits.

4. An apparatus as claimed in claim 3 in which there are two barriers one on either side of the weighing means so that the same weighing means may be used either entering or leaving the secure area.

5. An apparatus as claimed in claim 4 in which the means for weighing is a large rigid plate set into the floor of the exit or entry and mounted on load cells.

6. An apparatus as claimed in claim 5 in which the plate has a marked area or depressions indicating where the user is to stand.

7. An apparatus as claimed in either of claims 5 or 6 in which three load cells are arranged supporting the plate such that, in use, two are under compression and one is under extension and that the load on each cells is approximately even.

8. An apparatus as claimed in any one of claims 3 to 7 in which a machine readable ticket is issued once the weight has.been recorded.

9. An apparatus as claimed in claim 8 in which the ticket is presented on leaving the secure area to enable comparison between the entry and exit weights.

10. A method of dynamic weighing which comprises digitalising the output from a weighing platform, sampling the digitalised output over a short period of time, and computing an average weight from the sample.

11. An apparatus according to any one of claims 3 to 9 incorporating means for digitalising the output from the weighing platform, sampling the digitalised output over a short period of time, and computing an average weight from the sample.

12. A method of weighing persons entering an area in which the total weight load must be controlled which comprises positioning an apparatus according to any one of claims 3 to 11 at the entry to the area and summing the successive weighings in order to obtain the total.

13. A method of preventing the unauthorised removal of items from secure areas substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.

14. A weighing apparatus substantially as hereinbefore described with reference to and as illustrated in Figures 1, 2 or 3 of the accompanying drawings.