GB2284088A - Alarmed barriers - Google Patents

Abstract

An alarmed barrier (10) for example at a supermarket checkout, is automatically monitored so that, if the barrier is not closed when the checkout supervisor leaves, an alarm sounds (23) after a predetermined time. The presence of the supervisor is monitored eg. by an ultrasonic transmitter (16) and receiver (17), producing variable signals during occupation of the checkout, serving to reset a timer (21). When movement ceases, indicating the absence of the supervisor, an output latch (22) operates the sounder (23) unless the barrier (10) is closed, opening a normally closed reed switch (13) by means of its magnetic attachment (12). <IMAGE>

Description

ALARMED BARRIERS The present invention relates generally to alarmed checkout barriers and is more especially but not exclusively concerned with the alarmed barriers to be found at the checkouts in supermarkets.

Other checkouts could also be provided with alarmed barriers, however, such as an exit from a railway station platform, an exit from a passport control at an airport, or indeed any other passageway to be monitored.

The primary purpose of any alarmed checkout barrier is not to secure the checkout against use by shoppers or passengers because it may be necessary for the checkout to be capable of use as an exit in the event of an emergency. The barrier at the checkout should thus be easily removable by the public.

Instead, the primary purpose of any alarmed checkout barrier is to attract the attention of a supervisor in the event of unauthorised removal of the barrier. This is usually achieved by means of an audible and/or visual warning signal given by the alarm.

It is also known, as disclosed in my earlier co-pending British patent application 2266983, for the alarm to give a warning signal if the supervisor leaves the checkout without first securing the barrier.

According to that invention, an alarmed barrier, for use in monitoring improper use of a passageway, comprises an alarm capable of giving a visual and/or audible warning signal, a barrier capable of selectively either blocking or not blocking the passageway, and a pair of monitoring controls arranged in series with the alarm, one of the controls being operable by a supervisor and the other of the controls being connectible to the barrier.

The improvement contemplated by the present invention is to help ensure that the passageway to be monitored cannot be left both unmanned and unsecured by human failure.

According to the present invention, there is provided an alarmed barrier, for use in monitoring improper use of a passageway, comprising an alarm capable of giving a visual and/or audible warning signal, a barrier capable of selectively either blocking or not blocking the passageway, and a pair of monitoring controls arranged in operative series with the alarm, one of the controls monitoring whether the barrier is blocking the passageway, and the other control automatically monitoring whether a supervisor is in a predetermined position whereby the alarm gives the warning signal only when the barrier is not blocking the passageway and the supervisor is not in the predetermined position.

The alarmed barrier may have time delay means provided, associated with said controls so that the alarm does not give the warning signal as soon as the conditions for causing the warning signal have been satisfied.

An additional manager control may be provided for overriding the alarm or either or both of the monitoring controls.

Said other monitoring control may comprise an ultrasonic transmitter and receiver pair, capable of detecting the presence or absence of the supervisor.

Alternatively, said other monitoring control may comprise a strain gauge, pressure pad or other switch fitted to a chair on which the supervisor is to sit or to the floor on which the supervisor is to rest or stand.

As a further alternative, said other monitoring control may comprise a photoelectric detector acting in the visible or infrared parts of the electromagnetic spectrum.

In all cases, the control for automatically monitoring the presence of the supervisor avoids any security lapse that might arise if the supervisor acted improperly by leaving the checkout without operating a non-automatic type of monitoring control.

The detection of the presence of the supervisor means that the alarm is effectively switched off, even when the barrier is not blocking the passageway at the checkout, until such time as the presence of the supervisor is no longer detected whereupon the alarm is effectively switched on.

Before discussing the automatic monitoring control in more detail, it will be convenient to discuss the barrier and the monitoring control associated with the barrier.

The barrier may comprise a flexible belt, rope or chain capable of being positioned across the passageway.

One end of the barrier may be permanently secured at one side of the passageway and the other end of the barrier may be provided with removable attachment means such as a plug, hook or magnetic attachment at the other side of the passageway.

Alternatively the alarmed barrier may comprise a gate pivotally mounted across the passageway.

A switch may be provided to detect whether the barrier is open or closed.

The switch may comprise a magnetically operated reed switch or a microswitch.

An embodiment of the invention is now described by way of example only, with reference to the accompanying drawing, which is a block diagram illustrating an automatic checkout control barrier.

Referring to the drawing, a barrier is diagrammatically shown in the form of a chain at 10. One end 11 is fixed at a side wall of a passageway to be rendered secure. The other end is provided with a magnet 12 which can be attached to a socket 13 on the other wall of the passageway. A normally closed reed switch is provided in the socket, the state of which is changed by the attachment of the magnet to close off the passageway with the chain. The reed switch is connected in circuit with a control box 14 of the apparatus, through a coiled cable with a jack plug engaging a socket 15 of the control box.

The apparatus also includes an ultrasonic transmitter 16 and receiver 17, which are positioned close to the checkout supervisor's legs. The ultrasonic transmitter 16 is arranged to emit sound at a frequency of 40 KHz. This sound is received by the receiver 17 at varying intensities, depending on objects directly in front of the receiver, in other words, depending on the presence of the operator. While normal movements are detected, the main control unit holds the alarm off. If, however, the operator leaves the checkout, then no movement is detected by the receiver 17. In these circumstances, the magnet 12 must be attached to the socket 13 to close the barrier.

The receiver 17 generates a signal which is amplified at 18.

A voltage level directly proportional to the signal from the receiver is generated in the voltage level generator 19. As the signal, and hence the voltage level, changes due to movement at the checkout, a reset pulse is generated in the reset pulse generator 20, to reset a timer circuit 21. If no signal is available to reset the timer within the permitted time delay, because the checkout operator is not in place, the timer circuit sets the output latching circuit 22.

This operates the alarm sounder 23, unless the magnet 12 is in position at the socket 13, opening the normally closed reed switch.

Thus, the checkout operator cannot leave the checkout for more than the time permitted by the delay timer 21, unless the barrier chain 10 has been closed. The delay should be sufficient to allow the operator to close the barrier, and can be adjustable.

To reset the alarm, the barrier can be closed, opening the reed switch of the socket 13. Alternatively, the operator returning to the checkout will reset the alarm, via the ultrasonic transmitter and receiver, which will again detect movement. As a further alternative a keyswitch can be provided for a store manager to operate to selectively disable the alarm at the checkout. Such a keyswitch is indicated at 24. As a further option, the manager can use a remote control to send a control signal to a remote-control reset 26, which also acts to reset the delay timer circuit for a short time.

Both mains and battery power are available. Usually, the apparatus is mains powered via a transformer 27 to provide a 12V regulated supply. A back-up battery 28 is provided, charging from the mains supply, and is coupled with a circuit to detect mains failure and switch to battery power as required. The battery may activate the alarm to indicate that the mains have been disconnected and this warning may be given by the alarm sounding at either full power or at a reduced level.

In alternative arrangements, the preferred transmitter, receiver and comparator are replaced by any one of the following:1) A photo transistor which detects the absence of light (not infrared) with a light transmitter on one side, and a receiver on the other. Appropriate components are those supplied by Radio Spares as part numbers RS 195883 for the emitter and RS 195906 for the receiver. The emitter requires a power source, and the signal from the receiver is then amplified.

2) An emitter the same as above, such as RS 195883, but using as a receiver an infrared control (remote), such as RS 577897.

3) An infrared emitter RS 195883 and an infrared modulated detector such as RS 564396.

4) A normal light source (not infrared) and a light dependent resistor, such as RS 596141 or RS 651507, which measures the difference in the strength of the light when someone is present.

5) An ordinary light or an infrared beam barrier detection using a transmitter and detector such as RS 630544 which covers both the transmitter and the receiver.

6) A passive infrared unit incorporating both the transmitter and the receiver such as RS 301123 or RS 647148 or RS 625299 or RS 625665.

7) A proximity device which senses presence, such as RS 285419 or RS 285425, which are inductive proximity detectors.

The relevant frequencies and distances for detection can be calculated for any given checkout or can be found by experience when fitting to a particular checkout.

Another method of switching the alarm off, but this time for as long as is desired, would be to interrupt the power supply in the circuit, so as to prevent a completed electrical current from reaching the buzzer.

A method of doing this would be by incorporating into a radio receiver, an electrical switch such as a relay so that when the switch is activated, it will switch off the electrical current, and will not switch it back on until it has been activated again.

Other remote ways of resetting the timer would be by infrared (remote), by ultrasonic (remote), by security tag presence as in office entry systems, by card entry system or by any form of key, either mechanical or electrical.

Consequently, it is possible for authorised personnel not to sound the alarm when they open the barrier.

The automatic monitoring control will be tuned, or set, to detect a supervisor's presence in or absence from a predetermined position, normally at a counter or the like at the checkout. The predetermined position may be defined more clearly by the provision of a shade or other guide around the receiver or other detector which may conveniently be secured to the counter for example below the counter near the supervisor's legs. Markings may be provided on the floor or elsewhere to help the supervisor visualise the limits of the detected region.

The box within which the alarm is housed may itself be secured by screws, Velcro (Registered Trade Mark) or other convenient fasteners to a backing plate permanently secured to the checkout. This facilitates ease of removal in the event that a faulty alarm has to be returned for servicing or replacement.

In the above-mentioned preferred application in a supermarket, the alarm remains switched off whenever the automatic monitoring control detects the presence of the cashier at the till of the checkout. The above-noted time delay allows the cashier to leave the till and put the barrier in place before the alarm is switched on. After the barrier has been set to block the passageway, and the checkout has been left unmanned, removal of the barrier will switch the alarm on in the normal way. To switch the alarm off, the circuitry may require key operation rather than mere correction of the cause of the alarm having been switched on.

It will be appreciated that the use of the invention is not limited to use at supermarket checkouts, but is generally applicable to passageways which are normally supervised to control access, for example entrances and exits to stations, halls theatres and other places of entertainment.

Claims (13)

1. An alarmed barrier, for use in monitoring improper use of a passageway, comprising an alarm capable of giving a visual and/or audible warning signal, a barrier capable of selectively either blocking or not blocking the passageway, and a pair of monitoring controls arranged in operative series with the alarm, one of the controls monitoring whether the barrier is blocking the passageway, and the other control automatically monitoring whether a supervisor is in a predetermined position whereby the alarm gives the warning signal only when the barrier is not blocking the passageway and the supervisor is not in the predetermined position.

2. An alarmed barrier according to claim 1 wherein time delay means are provided associated with said controls so that the alarm does not give the warning signal as soon as the conditions for causing the warning signal have been satisfied.

3. An alarmed barrier according to claim 1 or claim 2 wherein an additional manager control is provided for overriding the alarm or either or both of the monitoring controls.

4. An alarmed barrier according to any preceding claim wherein said other monitoring control comprises an ultrasonic transmitter and receiver pair, capable of detecting the presence or absence of the supervisor.

5. An alarmed barrier according to any one of claims 1 to 3 wherein said other monitoring control comprises a strain gauge, pressure pad or other switch fitted to a chair on which the supervisor is to sit or to the floor on which the supervisor is to rest or stand.

6. An alarmed barrier according to any one of claims 1 to 3 wherein said other monitoring control comprises a photoelectric detector acting in the visible or infrared parts of the electromagnetic spectrum.

7. An alarmed barrier according to any preceding claim and comprising a flexible belt, rope or chain capable of being positioned across the passageway.

8. An alarmed barrier according to claim 7 wherein one end of the barrier is permanently secured at one side of the passageway and the other end of the barrier is provided with removable attachment means such as a plug, hook or magnetic attachment at the other side of the passageway.

9. An alarmed barrier according to any of claims 1 to 6 an comprising a gate pivotally mounted across the passageway

10 An alarmed barrier according to any one of claims 7 to 9 and provided with a switch to detect whether the barrier is open or closed.

11. An alarmed barrier according to claim 10 wherein the switch comprises a magnetically operated reed switch.

12. An alarmed barrier according to claim 10 wherein the switch comprises a microswitch.

13. An alarmed barrier substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.