WO1993015484A1 - A device for activating or deactivating an antitheft device - Google Patents
A device for activating or deactivating an antitheft device Download PDFInfo
- Publication number
- WO1993015484A1 WO1993015484A1 PCT/DK1993/000032 DK9300032W WO9315484A1 WO 1993015484 A1 WO1993015484 A1 WO 1993015484A1 DK 9300032 W DK9300032 W DK 9300032W WO 9315484 A1 WO9315484 A1 WO 9315484A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- electromagnet
- strip
- field
- magnetic
- activating
- Prior art date
Links
Classifications
-
- G—PHYSICS
- G08—SIGNALLING
- G08B—SIGNALLING OR CALLING SYSTEMS; ORDER TELEGRAPHS; ALARM SYSTEMS
- G08B13/00—Burglar, theft or intruder alarms
- G08B13/22—Electrical actuation
- G08B13/24—Electrical actuation by interference with electromagnetic field distribution
- G08B13/2402—Electronic Article Surveillance [EAS], i.e. systems using tags for detecting removal of a tagged item from a secure area, e.g. tags for detecting shoplifting
- G08B13/2405—Electronic Article Surveillance [EAS], i.e. systems using tags for detecting removal of a tagged item from a secure area, e.g. tags for detecting shoplifting characterised by the tag technology used
- G08B13/2408—Electronic Article Surveillance [EAS], i.e. systems using tags for detecting removal of a tagged item from a secure area, e.g. tags for detecting shoplifting characterised by the tag technology used using ferromagnetic tags
- G08B13/2411—Tag deactivation
-
- G—PHYSICS
- G08—SIGNALLING
- G08B—SIGNALLING OR CALLING SYSTEMS; ORDER TELEGRAPHS; ALARM SYSTEMS
- G08B13/00—Burglar, theft or intruder alarms
- G08B13/22—Electrical actuation
- G08B13/24—Electrical actuation by interference with electromagnetic field distribution
- G08B13/2402—Electronic Article Surveillance [EAS], i.e. systems using tags for detecting removal of a tagged item from a secure area, e.g. tags for detecting shoplifting
- G08B13/2451—Specific applications combined with EAS
- G08B13/246—Check out systems combined with EAS, e.g. price information stored on EAS tag
Definitions
- the invention relates to a device for activating or deactivating an antitheft device, preferably in form of at least one strip with at least one layer of magnetic, soft material and at least one layer of magnetic, hard material, said device upon an activation and a deactivation, respectively, of the strip being capable of providing a characteristic magnetizing pat ⁇ tern which is removable by means of the erasing AC magnetic field pro ⁇ quizd by said device.
- a device of this type where the magnetising pattern can be removed by means of a horseshoe-formed electromagnet, the field between the poles of the magnet being utilized.
- This field is, however, not particularly homogenous.
- the field is substan ⁇ tially homogenous in the longitudinal direction of the pole shoe.
- Such an erasing magnet is produced by SIGMA.
- Such an electromagnet requires relatively much iron for the production of the core, and the complete structure is large and unhandy.
- the field is not homogenous transverse to the pole shoes.
- the object of the invention is to provide a device of the above type, whereby the amount of iron for the production of the core is substan ⁇ tially lower than hitherto known, and the field is more homogenous than previously known.
- the device according to the invention is characterised by said device being formed by a relatively long electromagnet, where the erasing AC magnetic field is the outer field at one long side of the electromagnet. The resulting field turned out to be sufficient for activating a strip. The field is almost homogenous, and the production of the core does not require much iron.
- Danish Patent Application No. 2646/84 discloses a device for activating and deactivating, respectively, a strip by means of a flat permanent magnet. It is, however, not possible to perform a demagnetizing by means of the DC-field.
- a first embodiment of the device is preferably intended to be built into a counter, and it may according to the invention be characterised by the relatively long electromagnet being relatively flat.
- the relatively long electromagnet being relatively flat.
- the flat structure of the electromagnet has the effect that the amount of iron for the production of the core can be additionally reduced.
- the relatively flat electromagnet may comprise a core of a substantially rectangular cross section, where ⁇ by the core is easy to manufacture.
- the relatively flat electromagnet may comprise a core of an oval cross section, whereby a particularly advantageous embodiment is obtained.
- the relatively flat electromagnet may have an ampere-turn of about 1 ,900.
- the resulting magnetic field is sufficient for activating the strip.
- Another embodiment of the device is preferably to be built into a port ⁇ able scanner and is according to the invention characterised by the relatively long electromagnet being mounted in the scanner in such a manner that said electromagnet in an activation/deactivation situation has a well-defined distance to the strip to be activated/deactivated by the AC-field of the electromagnet.
- the well-defined distance to the strip ensures an almost homogenous magnetic field.
- the electromagnet of the portable scanner may have an ampere-turn of about 400, whereby a magnetic field is obtained which is sufficient for activating the strip.
- Fig. 1 a illustrates a known device for deactivating an antitheft device as well as the antitheft device
- Fig. 1 b illustrates the antitheft device in the moment the deactivation is performed
- Fig. 1 c illustrates the antitheft device after deactivation, and after the device has been removed from the deactivation device
- Fig. 2 illustrates a first embodiment of a device according to the inven ⁇ tion for activating an antitheft device
- Fig. 3 illustrates the device of Fig. 2 when used in connection with a counter at an exit for customers
- Fig. 4 is a sectional view through a second embodiment of the device for activating an antitheft device and built into a portable scanner
- Fig. 5 is a bottom view of the device of Fig. 4, and
- Fig. 6 illustrates a diagram of a detected placed at the exit for detecting an activated antitheft device.
- Fig. 1 illustrates a known device 2 for deactivating an antitheft device in form of a strip 1 of magnetic material.
- the device 2 is formed by a plurality of juxtaposed permanent magnets, where the north pole and the south pole are alternately facing upwards.
- the strip 1 comprises at least one layer of magnetic soft material, i.e. amorphous material, such as of the type Allied 17 MA, and at least one layer of magnetic hard material.
- the strip 1 can for instance be fastened to a book which should not be illegally removed from a library or a bookshop. When the strip 1 has not been deactivated, it will be detected when passing an electromagnetic detector at the exit of the library or the bookshop, cf. Fig. 3.
- This detector produces an electromagnetic field and can respond to a material with a sharp-edged hysteresis corresponding to the layer of amorphous material. As a result, harmonics are generated to the frequency of the emitted electromagnetic field.
- the strip 1 can be deactivated by being "cut" to pieces figuratively speaking, cf. Fig. 1 , where the strip 1 in a manner known per se is moved towards a plurality of permanent mag ⁇ nets 2, where the north pole and the south pole alternately face the strip 1.
- the strip 1 is provided with a particular magnetizing pat- tern corresponding to a situation where the strip has been cut into sev ⁇ eral pieces magnetized in different directions, cf. Fig. 1 b . .
- the above permanent magnets 2 can for instance be placed below a counter top, cf. Fig. 3. As an alternative, they can be mounted on a roller across wnich the strip 1 is moved.
- the strip 1 can be activated by means of a device capable of generating a sufficiently strong and nevertheless almost homogenous magnetic field across an area of such a size that it can cover the strip 1 ; also when said strip is spaced up to 4 cm from the device.
- Fig. 2 illustrates a device to be built into a counter. The device is formed by an electromag ⁇ net 3 placed below the counter top. The electromagnet 3 is flat and rela ⁇ tively long.
- the core 3' is of a rectangular cross section and of a height substantially smaller than the width.
- a plurality of relatively thick wind- ings 3" are wound on the core 3', said windings standing a current of for instance 6 A.
- the ampere-turn is about 1 ,900.
- the outer magnetic field of one long side of the electromagnet 3 is utilized. This magnetic field is almost homogenous across an area corresponding to the product of the width and the length of the core 3'.
- the flat structure provides in addition a predetermined concentration of the outer field above the magnet.
- the outer field at one long side of the electromagnet is sufficient for erasing the magnetizing pattern shown in Fig. 1 a of the layer of amorphous material when the strip 1 is moved across said electromagnet 3.
- the current fed to the coil 3" is preferably AC.
- the current supply can, of course, be interrupted when the activ ⁇ ating device is not used.
- the current supply is typically 6A at a voltage of about 48 V.
- a blower for cooling the coil 3" can be included.
- the current supply to the coil 3" can be pulse-modulated.
- the preferably flat electromagnet can alternatively comprise a core of an oval cross section.
- the strips 1 can advantageously be inserted in books at a library or a bookshop, in which case a bar code detector 4 can be provided in front of the coil 3", said bar code detector 4 communicating with a computer registering for instance the returning of a book when said book is moved across the bar code detector 4 and the electromagnet 3 in a direction of the arrow shown in Fig. 2. Then the book cannot pass the detector 12, 13 of Fig. 3 and be removed from the library without activating an alarm, unless the strip inserted in the book has been deactivated, cf. Fig. 1.
- the activating device is built into a portable scanner, cf. Fig. 4.
- This portable scanner comprises a housing with a gripping member.
- the housing is bent and comprises at the end an opening, cf. Fig. 5, containing at least one electromagnet 6 of a substantially circular cross section.
- the electromagnet 6 is of a length of about 7 cm.
- the gripping member can be provided with a contact for the current supply to the electromagnet 6.
- the current sup ⁇ ply is typically 200 mA at a voltage of 15 V.
- the ampere-turn of the electromagnet 6 is about 400.
- the electromagnet 6 is mounted inside the scanner in such a manner that in an activation situation it has a well- defined distance to the strip 1 to be activated.
- the scanner can further ⁇ more be provided with a bar code detector registering the returning of a book in a computer through a cable 5 connected to the computer.
- the detector 12, 13 at the exit of the library or the bookshop comprises a transmitter and a receiver.
- the transmitter transmits a sinus-shaped signal of for instance 1 kHz via a frame aerial.
- a likewise frame receiver aerial communicates with a receiver detecting one or more harmonics of the transmitted signal frequency.
- the detector activates an alarm if the intensity and/or the composition of the harmonics correspond to the harmonics generated by a passage of an activated strip.
- Fig. 6 illustrates an example of how the detector can be shaped.
- An oscillator 11 transmits a sinus-shaped signal of a frequency of 1 kHz. This signal is amplified and transmitted to a transmitter aerial 12. From a receiver aerial 13, the received signal is transmitted to a detector 14 and a bandpass filter 15. The bandpass filter 15 has a centre frequency corresponding to the ninth harmonic, i.e. 9 kHz. The signal from the bandpass filter 15 is then mixed at 16 with the ninth harmonic of the output signal of the oscillator 1 1 . When the signal from the mixing step 16 exceeds a predetermined value, the exceeding indicates the presence of an activated strip 1 in the area being observed by the detector.
Landscapes
- Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Automation & Control Theory (AREA)
- Computer Security & Cryptography (AREA)
- Electromagnetism (AREA)
- General Physics & Mathematics (AREA)
- Burglar Alarm Systems (AREA)
Abstract
Description
Claims
Priority Applications (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
CZ932012A CZ9302012A3 (en) | 1992-01-28 | 1993-01-28 | Device for activation and deactivation of theft preventing apparatus |
JP5512871A JPH06506567A (en) | 1992-01-28 | 1993-01-28 | Device for activating or deactivating anti-theft devices |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DK102/92 | 1992-01-28 | ||
DK10292A DK10292A (en) | 1992-01-28 | 1992-01-28 | DEVICE FOR THE ACTIVATION / DEACTIVATION OF A THEFT SECURITY MARKETS |
Publications (1)
Publication Number | Publication Date |
---|---|
WO1993015484A1 true WO1993015484A1 (en) | 1993-08-05 |
Family
ID=8089761
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/DK1993/000032 WO1993015484A1 (en) | 1992-01-28 | 1993-01-28 | A device for activating or deactivating an antitheft device |
Country Status (6)
Country | Link |
---|---|
EP (1) | EP0577807A1 (en) |
JP (1) | JPH06506567A (en) |
AU (1) | AU3449693A (en) |
CZ (1) | CZ9302012A3 (en) |
DK (1) | DK10292A (en) |
WO (1) | WO1993015484A1 (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP1064631A1 (en) * | 1998-01-30 | 2001-01-03 | Sensormatic Electronics Corporation | Eas marker deactivation device having core-wound energized coils |
Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4141078A (en) * | 1975-10-14 | 1979-02-20 | Innovated Systems, Inc. | Library circulation control system |
US4568921A (en) * | 1984-07-13 | 1986-02-04 | Knogo Corporation | Theft detection apparatus and target and method of making same |
US4575624A (en) * | 1982-12-01 | 1986-03-11 | Rheinmetall Gmbh | Arrangement for activating and/or deactivating a marker strip having a magnetizable layer |
US4956636A (en) * | 1988-08-09 | 1990-09-11 | Thorn Emi Plc | E.A.S. tag having a control component with selectively magnetizeable regions |
EP0457078A2 (en) * | 1990-05-16 | 1991-11-21 | Minnesota Mining And Manufacturing Company | Electro-magnetic desensitizer |
-
1992
- 1992-01-28 DK DK10292A patent/DK10292A/en not_active Application Discontinuation
-
1993
- 1993-01-28 JP JP5512871A patent/JPH06506567A/en active Pending
- 1993-01-28 CZ CZ932012A patent/CZ9302012A3/en unknown
- 1993-01-28 EP EP19930903190 patent/EP0577807A1/en not_active Withdrawn
- 1993-01-28 WO PCT/DK1993/000032 patent/WO1993015484A1/en not_active Application Discontinuation
- 1993-01-28 AU AU34496/93A patent/AU3449693A/en not_active Abandoned
Patent Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4141078A (en) * | 1975-10-14 | 1979-02-20 | Innovated Systems, Inc. | Library circulation control system |
US4575624A (en) * | 1982-12-01 | 1986-03-11 | Rheinmetall Gmbh | Arrangement for activating and/or deactivating a marker strip having a magnetizable layer |
US4568921A (en) * | 1984-07-13 | 1986-02-04 | Knogo Corporation | Theft detection apparatus and target and method of making same |
US4956636A (en) * | 1988-08-09 | 1990-09-11 | Thorn Emi Plc | E.A.S. tag having a control component with selectively magnetizeable regions |
EP0457078A2 (en) * | 1990-05-16 | 1991-11-21 | Minnesota Mining And Manufacturing Company | Electro-magnetic desensitizer |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP1064631A1 (en) * | 1998-01-30 | 2001-01-03 | Sensormatic Electronics Corporation | Eas marker deactivation device having core-wound energized coils |
EP1064631A4 (en) * | 1998-01-30 | 2005-02-23 | Sensormatic Electronics Corp | Eas marker deactivation device having core-wound energized coils |
Also Published As
Publication number | Publication date |
---|---|
DK10292D0 (en) | 1992-01-28 |
DK10292A (en) | 1993-07-29 |
AU3449693A (en) | 1993-09-01 |
EP0577807A1 (en) | 1994-01-12 |
JPH06506567A (en) | 1994-07-21 |
CZ9302012A3 (en) | 1994-03-16 |
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