Abstract:
Absorbent pads with theft alarm activator elements concealed from view within each individual pad. These pads are designed for inclusion in a tray with a meat, fish or poultry product. The alarm activator element in each pad may be a strip or wire of magnetic material of suitable magnetic retentivity. In an alternative arrangement, a resonator may be used in conjunction with a magnetic strip which controls its resonant frequency. In the case of meat or poultry product pads, the element is cored into the pad between pluralities of laminated layers of tissue, cellulose, airlaid or composite. The element may be positioned between adjacent pairs of laminated tissues in a composite pad.

Description:
This application is a 371 of PCT/US 00/11343 filed Apr. 26, 2000 which claims benefit of 60/132,131 filed on Apr. 30, 1999. 
    
    
     BACKGROUND OF THE INVENTION 
     This invention relates to absorbent pads fabricated of laminated layers of absorbent tissue and, more particularly, to such pads which contain theft alarm activators therein. 
     Absorbent pads particularly designed for packaging with meat, poultry and fish food products are used in food markets, poultry processing plants and the like to reduce product display costs and to provide a cleaner, more attractive product. These pads are generally wrapped with the food product on the underside thereof to absorb liquids which may “bleed” from the product. In poultry products, for example, it is customary to place the poultry parts of a given package in a molded shallow tray of foamed plastic or the like. One of these absorbent pads is placed in the bottom of the tray and the poultry parts are placed thereon. The complete package is then wrapped with clear polyethylene or the like. 
     Packaged meat products sold in retail establishments, such as meat markets and supermarkets, may have a significant monetary value. Typically, such products will have a price of several dollars or even a dollar value in double digits. This level of value is such that shoplifting begins to become a serious problem. At the same time, it begins to be worthwhile for the marketing establishment to incur the additional expense of theft detection systems in order to prevent or deter shoplifting. 
     Typically, such systems work with products including an alarm activator element (a “tag”), a device for deactivating the element at the point of sale, such as a checkout counter, and a sensor at a point where people exiting the establishment must pass by. In one such system, the activator element is a small strip or wire of magnetic material which is initially magnetized as a permanent magnet. In conjunction with such a system, there is a device at the checkout counter for generating a demagnetizing field. If the activator element or “tag” is not demagnetized, it activates the theft alarm when the person carrying the product passes by the sensor. 
     Another theft detection system, similar in concept but using a somewhat different tag and means and method for deactivating the tag, is also known in the art. This utilizes tags (alarm activator elements) based on “acoustomagnetic” principles. The system operates at a carefully chosen narrow band of low radio frequencies, for example 58 kilohertz (kHz). The selected frequencies minimize any interference from other electronics. 
     In this system, the tag contains a resonator made of an amorphous magnetic material of a precise length and thickness, which is excited by low-frequency radio signals generated by a transmitter at the store&#39;s entrance/exit. The resonator vibrates at the same frequency, thus transmitting an identical signal. A receiver which is also positioned at the entrance/exit detects the resonator&#39;s signal and initiates an alarm. 
     One of the benefits of this acoustomagnetic detection system is that the low-frequency radio signals from the transmitter can penetrate foil shielding which might be used by a would-be shoplifter to defeat other types of detector units. 
     One particular theft detection system, based on acoustomagnetic principles, provides a transmitter unit mounted at a pedestal adjacent a store entrance or checkout aisle. This unit transmits 58 kilohertz low-radio-frequency pulses (referred to as “blue pulses”) at 11-millisecond intervals. A resonator positioned inside an absorbent pad of the present invention, when passing through the pedestal, begins to vibrate at 58 kilohertz, identical to the transmitted frequency, thereby sending “red pulses”. A receiver, also installed at the pedestal, is turned on during the 11-millisecond interval between the blue pulses so that it can pick up the red pulses emitted by the tag installed in the product in response to the transmission of the blue pulses. If the receiver receives a signal at least four times, it sets off an alarm. 
     The tag contains a magnetized strip adjacent to the resonator which insures that the oscillations of the resonator remain precisely at 58 kilohertz. A scanning device at the checkout counter can turn off the tag when the merchandise is sold by demagnetizing the strip or by altering its magnetic properties. At that point the resonator either does not vibrate (does not emit red pulses) or it resonates at the wrong frequency so that its pulses are not recognized by the receiver. 
     U.S. Pat. No. 5,320,895 of Lionel M. Larsonneur and Stanley E. Schilcher discloses an absorbent pad for use with meat and poultry products in retail sale packages. The disclosure of that patent is incorporated herein by reference as though set out in haec verba. It has a laminated tissue absorbent mat sandwiched between upper and lower plastic sheets. During production of the pad, aligned channels are established through the pad from top to bottom by the penetration of a series of perforating pins. 
     In the case of absorbent pads having theft alarm activator elements which are used with meat and poultry products, the packaging is such that the pad is usually visible, at least in major extent, at the underside of the product within its transparent wrapping. For pads such as are known in the prior art having an alarm activator element, the element is generally readily apparent to a discerning shoplifter because it is positioned along the upper exterior surface of the pad. It would be preferable for such an absorbent pad to have its theft alarm activator element out of sight within the pad, such as between the tissue layers of an absorbent pad constructed of tissue layer laminations. Other materials suitable for the laminated layers are cellulose, airlaid and composites. 
     SUMMARY OF THE INVENTION 
     In brief, particular arrangements in accordance with the present invention involve absorbent pads in which the absorbent core of the pad is constructed preferably of a plurality of tissue layers. These core pads are constructed of multiple tissue laminations and include an alarm activator element which is “cored into” the pad. This configuration is only feasible with laminated tissue pads or with composite pads of tissue laminations because of the ability of the laminated tissue construction to hold the alarm activator element in place without it migrating about in the pad. Placement of the alarm activator element within the tissue pad core in this fashion ensures that it is not apparent by inspection from outside the wrapped product. Thus, an unsuspecting shoplifter has no idea that what he is attempting to remove from the sales establishment contains. an alarm activator until the alarm sounds as he passes by the activator sensor near the exit of the establishment. In addition to theft detection, publication of the use of alarm activators is an effective theft deterrent. 
     In accordance with a further aspect of the invention, another particular arrangement comprises a composite of layered tissue pads with an alarm activator element positioned between a pair of such pads. This permits the inclusion of such an element within a composite absorbent pad containing individual layered pads fabricated in accordance with the teaching of the above-referenced Larsonneur-Schilcher patent. The overall composite product actually incorporates two pads fabricated in accordance with the teaching of the Larsonneur-Schilcher patent between which an individual alarm activator element is placed. A single perforated pad prepared as disclosed in that patent may be fabricated to contain an alarm activator element placed between the rows of perforations, if desired. The product preferably includes an enclosing envelope or shell of plastic or some other suitable material with one or both of the upper and lower layers perforated as may be desired for most effective absorption and retention of liquid within the composite pad. Because of the forces holding the two pads together within the external sealed envelope, migration of the internal alarm activator elements is prevented. 
    
    
     BRIEF DESCRIPTION OF THE DRAWING 
     In the accompanying drawings: 
     FIG. 1 is a schematic representation, partially broken away, of a pad of the present invention, showing an alarm activator element positioned between pluralities of tissue layers; 
     FIG. 1A is a schematic representation of an alternative alarm activator element for the pad of FIG. 1; 
     FIG. 1B is a view indicating the use of the pad of FIG. 1 in association with a poultry product; 
     FIG. 1C is a view indicating the use of the pad of FIG. 1 in association with a meat product; 
     FIG. 2 is a schematic representation of a portion of a production line for producing pads such as that depicted in FIG. 1; and 
     FIG. 3 is a side sectional view of one particular composite pad in accordance with the present invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     In the schematic representation of FIG. 1, which is intended to show a somewhat “generic” example of different versions of absorbent pads which may be constructed in accordance with the present invention, a pad  10  is shown having an top layer  11  and a bottom layer  12  enclosing a plurality of laminated tissue layers  14   a  and  14   b . The pad  10  is shown with a border  13  comprising longitudinal sections  13   b  and transverse sections  13   a . These borders are typically sealed together, as by pressure, adhesive, ultrasonic bonding or the like, but it will be understood that either or both of the sections  13   a  and  13   b  may be absent, depending upon the manner in which the pad  10  is fabricated and the way it may be cut or slit to separate individual pads from a continuous assembly of various layers. 
     The laminated layers  14   a  and  14   b  are shown formed of individual tissue layers  18 . It will be understood that the laminations  14   a  and  14   b , as shown, may represent respective individual pads in a composite assembly or, they may simply represent respective pluralities of individual layers  18  of tissue, cellulose, airlaid or composites respectively above and below the element  16 . 
     Element  16  is shown as a strip representing an alarm activator element of a first type known in the art. In one example, the theft alarm activator element  16  is constructed of a magnetic material having retentive magnetic properties so that it may be magnetized to hold a magnetic field. Such element  16  is responsive to a strong demagnetizing field applied in the vicinity of the pad  10  so that it loses its ability to activate an alarm in a system having a sensor which is designed to respond to the presence of the element  16  in the pad  10  in its initial magnetic state. Once deactivated by the demagnetizing field, commonly present at the checkout counter of a retail establishment, the sensor near the exit of the establishment no longer responds to the presence of the element  16  and thus the pad  10 , together with whatever product it may be packaged with, may be taken from the establishment without activating the alarm. Other alarm activator elements and systems known in the art, such as the acoustomagnetic tag and system described hereinabove, which perform the equivalent function may be used as the element  16 . Although the element  16  is shown aligned longitudinally in the center of the pad  10 , it may be aligned in a different orientation (e.g., transversely) and may be displaced from the center so long as it remains enveloped by the tissue layers  14   a ,  14   b  so that it is held in position and is not visible outside the pad. 
     In FIG. 1A, an alternative to the element  16  of FIG. 1 is shown. This element  16   a  is a magnetic wire of substantially the same material as the magnetic strip  16  of FIG.  1  and it may be used as an alternative alarm activator element, if desired. 
     FIG. 1B shows a poultry product packaged for sale. As shown in FIG. 1B, a prepared chicken or other fowl product  74  is in place on an absorbent pad  10  within a tray  76 . An outer wrapping of suitable thermoplastic film material  75  is positioned over the fowl  74  and heat sealed or otherwise closed beneath the tray  10  in conventional fashion, forming a completed food package. In similar fashion, as shown in FIG. 1C, a corresponding meat package  82  containing a product  80 , such as a steak, a roast or other cut of meat, is in position on an absorbent pad  10  within a tray  86 . The entire package is wrapped with a suitable transparent plastic wrapping material  84  and sealed on the underside. 
     FIG. 2 schematically represents portions of a production line for the fabrication of products in accordance with the present invention. This is not intended to show actual details of such a production line, which are known in the art, but merely indicates an understanding of the addition of fabrication steps of the present invention. 
     In FIG. 2, a plurality of rolls  42  are shown, each providing a single layer of cellulose tissue  18  for a pad such as that shown in FIG.  1 . Each layer of tissue  18  is drawn from its corresponding roll  42 , over a corresponding idler roll  44 , and then, with the other layers  18 , between a pair of rolls  46  which may serve to draw the individual lamination layers  18  along the production line. The tissue layers  18  are then stitched together to form a continuous strip of laminated tissue layers at the stitching stage  58  comprising a stitching machine  60  coupled to a control element  62 . 
     From the stitching stage  58 , the laminated layers of cellulose tissue move along the production line, as indicated in FIG. 2, to receive the top and bottom layers  48  of polyethylene for the outer plastic layers of the finished pads, drawn from rolls  50  and  51 . As the layers  48  proceed from the rolls  50 ,  51 , they pass through perforators  56  which form a plurality of small holes in the plastic layers to admit liquid for absorption into the laminated core of the finished pads. The thus-formed strip of laminated sheet material passes between bonding rolls  54  where the side edges of the top and bottom plastic layers are sealed together by pressure bonding. 
     Between upper and lower sets of rolls  42  and idler rolls  44  is a plurality of individual activator elements  16  supported between carrier webs  20  for introduction into the laminating line between upper and lower sets of individual tissue layers  18 . This arrangement serves to place the individual alarm activator element  16  between the upper and lower pluralities  14   a ,  14   b  of tissue layers  18  shown in the finished product  10  of FIG.  1 . The spacing between the elements  16  of FIG. 2 is such as to permit appropriately indexed slitting knives and cutters to perform the cutting operations between the elements  16 . 
     Following the fabrication steps described, as represented in FIG. 2, the laminated sheet material is directed to slitting knives and transverse cutters (not shown) to finish producing the pads in the desired dimensions—for example, 4¼×{fraction (6 1/2)} inches or any other size which may be desired. The cutting blades lightly adhere the laminations at all edges, forming the borders  13  as shown in FIG.  1 . 
     FIG. 3 is a side sectional view of a composite pad  300  formed by a pair of individual pads of the above-cited Larsonneur-Schilcher patent 5,320,895. As described in that patent, these individual pads  302  are fabricated by using a perforating wheel on the pad production line which penetrates entirely through the pad at regular intervals to form the channels  304 . Two of these pads  302  are then assembled as a composite with a magnetic strip  16  between them. The magnetic strip  16  may be of the permanent magnetic type or of the acoustomagnetic type, both of which are described hereinabove and shown as alternatives in FIGS. 1 and 1A. Finally, this assembly is encased in a shell having a preferably liquid impervious upper layer  310  and a preferably liquid permeable lower layer  312  of polyethylene or some other appropriate plastic with the periphery being sealed as shown at  314 . Composite pads as shown in FIG. 3 function in the manner described with respect to the pad of FIG. 1, the alarm activator magnetic strip  16  serving to activate the sensor of a theft alarm system unless it is demagnetized prior to entering the vicinity of the sensor. 
     Although there have been described hereinabove various specific arrangements of ABSORBENT PADS HAVING THEFT ALARM ACTIVATORS THEREIN in accordance with the invention for the purpose of illustrating the manner in which the invention may be used to advantage, it will be appreciated that the invention is not limited thereto. Accordingly, any and all modifications, variations or equivalent arrangements which may occur to those skilled in the art should be considered to be within the scope of the invention as defined in the annexed claims.