Not Applicable
Not Applicable
1. Field of the Invention
This application relates to electronic article surveillance (EAS) tags, and more particularly to a reusable EAS tag that is proximity detached by electromagnetic energy.
2. Description of the Related Art
Electronic article surveillance systems are well known in the art and are used in many applications including inventory control and to prevent theft and unauthorized removal of articles from a controlled area. Typically, in such systems a system transmitter and a system receiver are used to establish a surveillance zone, which must be traversed by any articles being removed from the controlled area.
An EAS tag is affixed to each article and includes a marker or sensor adapted to interact with a signal being transmitted by the system transmitter into the surveillance zone. This interaction causes a further signal to be established in the surveillance zone which further signal is received by the system receiver. Accordingly, upon movement of a tagged article through the surveillance zone, a signal will be received by the system receiver identifying the unauthorized presence of the tagged article in the zone.
Certain types of EAS tags have been designed to be reusable and, thus, include releasable attachment devices for affixing the tags to the articles. Such attachment devices are further designed to be releasable by authorized personnel only so that unauthorized removal of a tag from its article is avoided. To this end, many attachment devices are made releasable only through the use of an associated special tool or detaching mechanism.
An EAS tag employing an attachment device and an associated detacher is described in U.S. Pat. No. 3,942,829, entitled Reusable Security Tag, issued to Humble, et al. on Mar. 9, 1976. The EAS tag of the '829 patent includes a tag body and an attachment device in the form of a tack assembly. The tack assembly includes an enlarged head and a tack body having a pointed end, which serves to pierce through an article and to be receivable in and clamped to the tag body. This secures the article and tag together.
In the tag of the '829 patent, the tack is clamped to the tag body using a spring clamp formed as a clutch lock with spreadable jaws. Once the article is pierced, the pointed tack end is received in the tag body and is secured between the jaws of the clutch lock. This locks the tack and the tag body forming the EAS tag to the article so that the tag and article cannot be readily separated from each other.
In order for authorized personnel to be able to release the tack from the clutch lock and, therefore, the tag from the article, the '829 patent utilizes a detacher mechanism which is adapted to grip the tag body and apply a bending force thereto. This force is sufficient to deform the clutch lock so that the jaws of the clutch lock are spread apart, thereby releasing the tack. The tack can then be removed from the tag body so that the article and tag become separated from one another.
To permit the bending of the tag body sufficiently to deform the clutch lock, the tag body of the '829 patent must be made of a flexible material. Typically, flexible plastic materials such as, for example, polypropylene, have been used. Such materials, however, are susceptible to being cut and damaged. This tends to be a disadvantage, since it increases the likelihood that the locking feature of the tag can be separated from the EAS sensor part of the tag or can be exposed and defeated.
Another type of EAS security device is known in which a variation of the spring clamp of the '829 patent has been incorporated into a so-called keeper for a compact disc. This type of device is disclosed in U.S. Pat. No. 5,031,756, entitled Keeper For Compact Disc Package Or The Like, issued to Buzzard, et al. on Jul. 16, 1991.
The keeper of the '756 patent comprises a rigid plastic frame. One side of the frame is provided with an enlarged section which houses a tack-like button assembly and a spring clamp as in the '829 patent. In this case, the spring clamp is used to lock the button assembly in a first position. In this position, the pointed end of the button assembly protrudes into the frame to pierce and hold to the frame a cardboard container containing a compact disc. As a result, unauthorized removal of the compact disc with the frame causes an EAS sensor also incorporated into the frame, to generate a detectable signal for alarming an EAS system.
In the keeper of the '756 patent, the enlarged section of the frame is provided with opposing linear slots, which lead to the region between the jaws of the spring clamp. By inserting ramped linear fingers into these slots, the fingers are guided into this region, causing the jaws to flex outward. This releases the button enabling it to be withdrawn from the cardboard container. The container and its housed compact disc can then be separated from the frame.
While the keeper of the '756 patent utilizes a spring clamp of the '829 patent type in a rigid frame, it also has certain drawbacks. One drawback is that the linear slots leading to the spring clamp permit in-line viewing and access to the clamp. This increases the susceptibility of the clamp to defeat, since linear objects can be inserted into the slots in an attempt to open the jaws. Another drawback is that the fingers of the detacher are required to be of high precision, since they must be received in the region between the spring clamp jaws. This increases the cost and complexity of the detacher.
U.S. Pat. No. 5,426,419, entitled Security Tag Having Arcuate Channel And Detacher Apparatus For Same, issued to Nguyen, et al. on Jun. 20, 1995, discloses an EAS tag that has a hard tag body, which is adapted to be releasable from an article in an easy and simple manner by insertion of an arcuate probe of an associated detacher device into an arcuate channel of the tag to release a spring clamp mechanism. The spring clamp mechanism is a releasable locking mechanism that prevents removal of the tack assembly that is adapted for insertion through an article, which is captured when inserted into an opening in a portion of the tag body. The EAS tag of the '419 patent is more difficult to defeat than the above tags and is in worldwide use.
The EAS tag of the '419 patent can be defeated by insertion of a segment of relatively rigid metal bent in an arcuate manner to simulate the arcuate probe of the associated detacher device. U.S. Pat. No. 6,373,390, entitled Electronic Article Surveillance Tag Having Arcuate Channel, issued to Hogan, et al. on Apr. 16, 2002, discloses a device usable in the EAS tag of the '419 patent to reduce the potential for defeats by insertion of simulated arcuate probes. As each improvement in defeat resistance is implemented, new techniques for unauthorized tag removal are developed. An improved EAS tag detachment mechanism is needed to reduce the incidence of unauthorized EAS tag detachments.
An alternate to a reusable EAS tag is a disposable EAS tag or EAS label. Instead of detachment from an article that is authorized for removal, EAS labels are typically deactivated so they do not interact with the EAS surveillance zone and are not detected by the associated EAS receiver when the article is removed. Deactivation is normally accomplished by exposing the label to an electromagnetic field or pulse of preselected waveform, frequency, amplitude, and/or duration. Deactivation normally occurs near the cash register in a retail environment, and may be linked to a barcode scanner or to radio frequency identification (RFID) equipment. In some cases, the deactivator equipment may be triggered as the article is scanned for checkout.
U.S. Pat. No. 5,867,101, entitled Multi-Phase Mode Multiple Coil Distance Deactivator for Magnetomechanical Marker, issued to Copeland, et al. on Feb. 2, 1999, and U.S. Pat. No. 6,060,988, entitled EAS Marker Deactivation Device Having Core-Wound Energized Coils, issued to Copeland, et al. on May 9, 2000, disclose deactivators suitable for deactivating magnetomechanical or acoustomagentic EAS labels and are available from Sensormatic Electronics Corporation, Boca Raton, Fla. Deactivators for radio frequency (RF), and other technology EAS labels are also commercially available. In some instances, retail merchants may use reusable EAS tags and disposable EAS labels in one store, which requires separate detaching and deactivation mechanisms for different purchases. If a deactivator could be used to detach EAS tags, the burden of the retailer to have multiple mechanisms would be eliminated, and the mechanical techniques for unauthorized detaching of EAS tags could also be reduced.
In addition, detaching of EAS tags requires the presentation of the tag to the detaching device and/or the application of mechanical force by the operator. Detaching by simply placing the EAS tag in proximity to a detaching mechanism would speed up the detaching process, thereby reducing the time required for each transaction, decreasing costs, and increasing customer satisfaction.
The present invention is an electronic article surveillance (EAS) tag that is detachable from an article by placing the EAS tag in proximity to a detaching device. The detaching device transmits a signal to detach the tag from an article to which the tag is attached. The tag includes an energy coupler, a micro-actuator, and a clamping mechanism.
In one aspect, the EAS tag is detachable from an article by an electromagnetic signal, and includes an energy coupler for receiving energy from the electromagnetic signal. The energy coupler provides electrical energy in response to the electromagnetic signal. An actuator, connected to the energy coupler, converts the electrical energy to mechanical energy. A clamping mechanism, connected to the actuator, prevents release of the tag from an article to which the tag can be attached. The clamping mechanism is responsive to the mechanical energy to enable release of the tag from the article to which the tag can be attached.
The energy coupler can be an inductively coupled coil or may include a battery and trigger mechanism for switching the battery on to apply power to the actuator.
The actuator can include a plurality of shape memory alloy members disposed in cooperative arrangement to provide movement, such as linear motion, upon conversion of the electrical energy to mechanical energy, the mechanical energy can be defined as the linear motion. The actuator could alternately be a piezoelectric member. The piezoelectric member deforms and provides movement in response to the electrical energy, and where the mechanical energy can be defined as the linear motion. The actuator could also be an electrostrictive polymer member. The electrostrictive polymer member compresses in thickness and elongates in length to provide movement in response to the electrical energy and where the mechanical energy can be defined as the linear motion.
The clamping mechanism can include a pin assembly having a pin body, and jaw assembly having at least one jaw moveable from a first position to a second position in response to the mechanical energy, the first position retaining the pin body in a locked position where the pin body can be inserted through an article and retains the tag to the article. The second position releases the pin body to move out of the article releasing the tag from the article. The clamping mechanism may include a release member responsive to the mechanical energy. Where the jaw assembly includes a leg member adapted for moving the jaw between the first position and the second position, the release member is disposed between the actuator and the leg member and where the mechanical energy includes linear motion to move the release member to engage and disengage the leg member to move the jaw from the first position to the second position, respectively.
Alternately, the actuator may include a plurality of shape memory alloy members. The plurality of shape memory alloy members are disposed in cooperative arrangement and adapted to provide rotational motion upon conversion of the electrical energy to mechanical energy, the mechanical energy defined as rotational motion.
The energy coupler further may include a decoder to recognize the transmitted signal where the transmitted signal includes a code or preselected waveform that is recognizable by the decoder.
The electronic article surveillance tag may be a container where the article to be protected is placed inside.
The invention includes methods for electronic article surveillance tag removal corresponding to the above apparatus.
Objectives, advantages, and applications of the present invention will be made apparent by the following detailed description of embodiments of the invention.
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Micro-actuator 4 converts the electrical energy received from energy coupler 2, into mechanical energy to actuate clamping mechanism 6. Micro-actuator 4 can be any actuator that, preferably, can receive sufficient energy from a conventional EAS tag deactivator and trigger the release of a clamping mechanism, and which is small enough to fit into an EAS tag. The selection of the micro-actuator 4 is dependent on the design of the clamping mechanism, and may include shape memory alloy, piezoelectric cantilever, and electroactive polymer actuator materials.
An example of shape memory alloy is a crystalline alloy of NiTi (Nickel and Titanium). When the NiTi alloy is heated, its crystalline structure rearranges resulting in a mechanical contraction. The material can be formed into a thin wire. When electrical current produced from energy coupler 2 is passed through the wire it is heated and contracts. When power is removed, the wire relaxes, but remains in its contracted position. Application of a tensile force is required to return the wire to its extended position. Many wires together can form an actuator having linear motion or actuation. The above described shape memory alloy exhibits what is called one-way response. In an alternate configuration called two-way response, the shape memory alloy wires can be trained to return to their extended position state when in the relaxed state. Further information about two-way shape memory effect can be found in: Perkins, J., et al., “The Two-Way Shape Memory Effect”, Engineering Aspects of Shape Memory Alloys, (Butterworth-Heinemann, 1990), at 195–206. Applications using shape memory alloy as described herein are commercially available from NanoMuscle, Inc., Antioch, Calif.
Piezoelectric material expands and contracts in relation to an applied voltage. The piezoelectric material can be bonded or connected to another material in a sandwich configuration to cause a bend in the material when the piezoelectric material expands or contracts. The bend can be used for linear actuation. Examples of piezoelectric material applications can be found in U.S. Pat. Nos. 6,071,087; 5,632,841; and 5,471,721.
Electroactive or electrostrictive polymer actuators can be formed by placing a dielectric film of elastomeric polymer material between two compliant electrodes. When a voltage difference is applied between the electrodes, the polymer is compressed in thickness and expanded in length and width as a result of the electrostatic forces generated by the free charges on the electrodes. Examples of elastomeric polymer material include, but are not limited to, polyurethane, silicone, fluorosilicone, ethylene propylene, polybutadiene, and isoprene. Compliant electrodes can be, but are not limited to, graphite powder, carbon powder, carbon fibers, and ionically conductive water-based polymers. The compliant electrodes can be formed directly onto the polymer film, or made as separate layers and then attached. The actuator may be constructed in different shapes such as planar, tubular, and the like, depending on the application. Further information on electrostrictive polymers can be found in: Pelrine, R., et al., “Electrostriction of Polymer Dielectrics with Compliant Electrodes as a Means of Actuation”, Sensors and Actuators A: Physical 64, 1998, at 77–85.
Clamping mechanism 6 can be any mechanical locking mechanism that prevents unauthorized removal of the EAS tag from the article to which it is attached. Examples of various clamping mechanisms have been previously described herein. A further example of clamping mechanism 6 is presented herein in the following description of one embodiment of the present invention.
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As described hereinabove, alternate actuators and energy couplers can be implemented along with alternate clamping mechanisms. Actuation by linear motion and rotation motion is described herein, but other actuations can be implemented to correspond to alternate clamping mechanism designs. The main feature of the invention is detaching using a transmitted signal or an electromechanical field instead of using conventional mechanical detaching of the EAS tag.
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It is to be understood that variations and modifications of the present invention can be made without departing from the scope of the invention. It is also to be understood that the scope of the invention is not to be interpreted as limited to the specific embodiments disclosed herein, but only in accordance with the appended claims when read in light of the forgoing disclosure.
Number | Name | Date | Kind |
---|---|---|---|
3942829 | Humble et al. | Mar 1976 | A |
4993245 | Ott | Feb 1991 | A |
4999819 | Newnham et al. | Mar 1991 | A |
5031756 | Buzzard et al. | Jul 1991 | A |
5426419 | Nguyen et al. | Jun 1995 | A |
5471721 | Haertling | Dec 1995 | A |
5523914 | Weck et al. | Jun 1996 | A |
5563583 | Brady et al. | Oct 1996 | A |
5632841 | Hellbaum et al. | May 1997 | A |
5867101 | Copeland et al. | Feb 1999 | A |
6060811 | Fox et al. | May 2000 | A |
6060988 | Copeland et al. | May 2000 | A |
6071087 | Jalink et al. | Jun 2000 | A |
6318137 | Chaum | Nov 2001 | B1 |
6373390 | Hogan et al. | Apr 2002 | B1 |
6646555 | Forster et al. | Nov 2003 | B1 |
Number | Date | Country | |
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20040100385 A1 | May 2004 | US |