Abstract:
A system for the display and distribution of multiple product items, where the product items bear radio frequency identification (RFID) tags, and an RFID reader is associated in close proximity for maintaining effectively continuous inventory control. A product display tray is provided with multiple product channels and individual pusher sleds in the product channels for urging the product items to the front of the display. The pusher sleds are actuated by non-metallic tension elements extending underneath the product items in conjunction with spring-actuated windup reels for maintaining the tension elements under tension urging the sleds in the desired direction. An RFID reader board is disposed directly under the product display tray, arranged for periodic reading of the entire contents of the tray. The non-metallic tension elements, extending underneath the product items, provide for actuation of the pusher sleds without interfering with the radio frequency identification procedures.

Description:
BACKGROUND OF THE INVENTION 
     Radio frequency identification (RFID) is finding increasing application to inventory and point-of-purchase control for products that are mass merchandised. In large chain store systems, product suppliers typically are allotted a very specific shelf or wall area in individual stores of the chain. Typically, substantial sums of money are required to be paid by the suppliers for the allotment of such shelf or wall space for the display of the supplier&#39;s product. Because of the significant costs involved, and the limited space available, suppliers devote considerable time and effort to the design of the planograms for their product space, seeking to achieve maximum product sales from the display space provided. In many cases, the manufacturers visit the individual stores on a regular basis to review the state of their planogram, and make certain that merchandise is displayed where it is supposed to be displayed, and that there are adequate quantities of each product. 
     RFID procedures can be employed to advantage in managing and monitoring such product displays on a remote basis, minimizing the need for personal visitations by manufacturer&#39;s representatives. Using RFID systems, each product item can be provided with an individual identification tag, which is specific not only to the class of product, but even individual to each particular product item within the class. A radio frequency reader element is associated with the product display, and is activated periodically, for example as frequently as twice a minute. When the reader is in operation, the identification tag of each product item within range of the reader is activated and returns its unique identification code to the reader, which can then transmit the information to any of various remote locations, enabling the supplier to know on a substantially continuous basis which product items are selling and the rate of such sales. Additionally, the RFID information transmitted can also indicate when a particular product item has been misplaced in the planogram, as frequently occurs when a prospective customer picks up an item for inspection and replaces it in a different location. The technology for such RFID inventory management systems is well known to those in the art. 
     Many products are preferentially displayed in columns which extend on a shelf or wall mounted in a row from front to back. Pusher means are provided at the back of the product column, such that when a customer selects and removes a product item from the front of the display, the balance of the product column will be moved forward by the pusher element acting on the back of the column. Such pusher arrangements are well known and in widespread use in merchandise displays. Typically, however, such pusher arrangements have been incompatible with RFID inventory management techniques, because of the interference caused by the metal spring element of the pusher device. 
     SUMMARY OF INVENTION 
     Conventional, widely used pusher arrangements for product displays typically employ a coiled strip spring, anchored at its forward end, and having its coiled body confined within portions of a movable pusher sled arranged for back to front sliding movement to urge product items in a forward direction. When loading a column of product items, the sled is moved to a retracted position. During the retracting movement, the strip spring is progressively uncoiled and the uncoiled portions extend along the bottom of the display column, lying underneath the various product items positioned in front of the pusher sled. As product items are removed from the column, the spring recoils itself, advancing the sled and urging the remaining products in a forward direction. 
     Although pusher sleds as of the type described above are in widespread use, they create a problem in connection with RFID inventory control, because of the presence of the metal spring material directly under the products, typically in close adjacency to the RF identification tag, which is preferentially mounted on the bottom of the product. 
     Pursuant to one aspect of the present invention, a novel and improved product pusher arrangement is provided which accommodates and optimizes the ability to monitor product items in a pusher activated display, using RFID techniques. To this end, the pusher sled incorporates a spring-operated reel carrying a flexible tape or the like formed of a non-metallic material, such as nylon or other suitable plastic. The non-metallic tape, serving as a tension element, is arranged to underlie the monitored product items, when the sled is in a retracted position. The arrangement is such that, as the sled is retracted, the non-metallic tension element is withdrawn from the wheel, which is simultaneously being acted upon by a spring associated with the reel, preferably housed internally thereof. As the sled is retracted, and the tension element is withdrawn from the reel, the spring is correspondingly wound up, urging the reel to rotate in a direction to retract the tension element. Thus, in the system of the invention, the metallic return spring element is positioned entirely behind the front surface of the sled, so as to be offset from the displayed product items, allowing the items to be reliably activated and read by a radio frequency reader device. 
     In a preferred and advantageous form of the invention, a product display arrangement incorporates a tray with laterally spaced dividing walls forming a multiple column product display. Each column is provided with a pusher sled of the type described above, including a spring-driven reel mounted on the sled and carrying a non-metallic tension element for urging the sled toward the front of the display. A radio frequency reader board, operating on known RFID principles, is mounted underneath the divided tray, so as to be directly underneath the product items displayed thereon. To advantage, the reader is repetitively activated to read the contents of each channel and identify each product remaining therein. The non-metallic tension elements of the several pusher sleds enable the individual products to be accurately detected, such that essentially real time inventory information is available to the store and to the supplier; The invention enables RFID detection and control to be effectively put to use in connection with pusher displays of all kinds, thus greatly expanding the practical utility of RFID inventory management techniques. 
    
    
     For a more complete understanding of the above and other features and advantages of the invention, reference should be made to the following detailed description of preferred embodiments thereof, and to the accompanying drawings. 
     DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of a typical tray for the display of small items of merchandise, incorporating features of the invention. 
     FIG. 2 is a perspective view, similar to FIG. 1, with parts broken away and with product items removed for illustration of structural features. 
     FIG. 3 is a perspective view of an advantageous form of pusher sled, incorporating features of the invention, utilized in the tray of FIG.  1 . 
     FIGS. 4 and 5 are top plan and side elevational views respectively of the pusher sled of FIG.  3 . 
     FIG. 6 is a perspective view of a tension element and reel forming part of the mechanism for moving the sled of FIG.  3 . 
     FIG. 7 is an exploded view illustrating the various elements forming the tension element and reel of FIG.  6 . 
     FIG. 8 is an enlarged perspective view of an advantageous form of axle pin which includes means for anchoring a windup spring. 
     FIG. 9 is a perspective view of an alternative form of tension element, shown with its associated windup reel. 
     FIG. 10 is an exploded view illustrating the display tray of FIG. 1 in conjunction with RFID reader components associated therewith. 
     FIG. 11 is a bottom perspective view of one of the product items of FIG. 1, illustrating an RFID identification tag associated therewith. 
     FIGS. 12,  13  and  14  are perspective views of first, second and third alternative forms respectively of pusher sleds that can be usefully employed in the system of the invention. 
    
    
     DESCRIPTION OF PREFERRED EMBODIMENTS 
     Referring now to the drawing, the reference numeral  20  designates generally a tray for the display of multiple product items  21 . The tray includes a plurality of divider walls  22  which form multiple product display channels  23  extending in a front-to-back direction within the tray. The tray can be placed upon a shelf (not shown) or secured by its back wall  24  to a vertical display wall (not shown) at the election of the merchandiser. 
     Each of the product channels  23  of the tray is provided with a pusher sled  25 , which will be described in more detail, which slides in the channel and constantly urges the column of product items  21  to the front of the channel. 
     In the system of the invention, the tray  20  is associated with an RFID reader board  26  (FIG.  10 ), which is mounted on a support panel  27  and provided with a plastic cover  28 . The support  27 , plastic cover  28  and RFID reader board  26  form a subassembly which is attached to the bottom of the display tray  20 , so as to place the reader board  26  in close proximity to the bottom wall  29  of the tray (see FIG.  2 ). 
     The RFID reader board  26  is based upon known technology and does not per se form part of this invention. By way of example only, the Doty U.S. Pat. No. 5,591,951 illustrates a type of RFID system for reading encoded information embedded in an identification tag attached to items of merchandise. Systems of this nature are well known and used for a number of purposes. Individual identification tags  30  (FIG.  11 ), are affixed to each product item  21 . The identification tags incorporate circuitry that is activated by radio frequency signals generated by the reader board  26 . In response to such activation, the identification tag transmits an identifying signal that is specific to the information embedded in the tag, which signal is received and processed by the reader board, all in accordance with generally known technology. It is within the contemplation of this invention that each product package will be provided with a unique identification tag  30  such that even identical product items, which might bear the same bar code identification, for example, will carry unique identifying information on the RFID tag  30 , such that the individual product items can be identified. By means not illustrated herein, but well known in the art, the information read by the reader board  26  can be transmitted to one or more remote locations for processing, such that the exact state of the merchandised carried by the tray  20  can be determined at any time. In the illustrated system, it is contemplated that the reader board  26  will scan the entire tray at, for example, 30 second intervals, so that real time inventory conditions are available to the merchandiser. 
     Preferably, the reader board  26  is set up with separate reader circuits  31  for each of the channels  23  of the tray  20 , enabling the channels to be read individually. 
     Ideally, a product display tray, such as shown in FIG. 1, incorporates pusher sleds  25  to keep moving the product columns forwardly as individual items are removed by customers. Heretofore, this has presented a serious obstacle to the use of RFID inventory control techniques because of the presence, in a typical pusher sled installation, of a metal strip coil spring associated with the sled and extending from the front of the tray channel  23  rearwardly to the sled, underneath all of the product items  21  in the channel. The presence of this metal strip interferes seriously with the accurate reading of the identification tags  30  by means of a reader board positioned underneath the tray, because the metal strip is interposed directly between the reader  26  and the identification tag  30 . 
     Pursuant to the invention, the above-described problem is obviated by providing a non-metallic tension element, which underlies the product items  21  and connects the pusher sled to the front of the tray. A spring-actuated windup reel is mounted at the back of the sled, such that a metallic spring associated therewith is positioned behind all of the product items of a column and does not interfere with reading of the individual identification tags  30 . 
     A particularly advantageous form of pusher sled utilized in the system of the invention is shown in FIGS. 4-10. The sled  25  is a molded plastic part comprising a front or pusher wall  35  and a bottom wall  36 . The sled is of a width appropriate to fit into the individual tray channels  23  for easy front and back sliding movement therein. The several tray channels  23  are provided with longitudinal slots  37  which engage a slide key  38  extending downward from the sled bottom  36 . An enlarged opening  39  is provided at the back of the channel to receive a cross bar portion  40  of the slide key  38  during initial assembly of the sled with the tray channel. 
     As illustrated in FIGS. 3-5, a windup reel  41  is mounted in the sled, by means of spaced-apart walls  42 . The windup reel, to be described in more detail, carries a tension element  43  formed of a non-metallic, flexible material, such as nylon tape. At its forward end, the tension element  43  carries a transverse toggle element  44  which can be received in a transverse slot  45  at the front of the tray channel  23 , to serve as an anchor attachment for the front of the tension element  43 . The sled  25  is mounted in the channel  23  by initially positioning the sled at the back of the channel and inserting the slide key  38  into the enlarged opening  39 . The sled is then moved forward, such that the cross bar  40  is out of alignment with the opening  39 , which locks the sled in the channel for front and back sliding movements. The toggle  44  is then inserted into the slot  45  at the front of the channel. 
     The windup reel  41  is spring driven to constantly urge the tension element  43  toward the reel, such that the sled is always urged forwardly in the channel, urging any product items positioned in the channel toward the front of the tray. 
     Referring now to FIGS. 6-8, an advantageous form of the windup reel comprises a two-part assembly. One of the parts  50  comprises a cylindrical drum  51  and circular side flange  52 . The drum  51  serves as a housing for a coiled strip spring  53  which fits snugly inside the drum  51  and typically tends to expand outwardly against walls of the drum. The outer end extremity  54  of the spring is bent outward and is received in a locking slot  55  in the wall of the drum  51 . 
     The second part of the two-part reel assembly comprises a cylindrical drum  56  and an outer circular flange  57 . The drum  56  is received telescopically over the outside of the drum  51  of the other half with a snug fit. No fasteners are required, as the windup reel  41  is confined between the walls  42  of the pusher sled. When the two halves of the assembly are joined, as shown in FIG. 6, the tension element  43  can be secured to the outer surface of the outer cylindrical drum  56 , by means of a section of adhesive tape  58 . In a similar manner, the toggle element  44  can be joined to the outer end of the tension element by means of a short section  59  of adhesive tape. 
     In the form of the invention illustrated in FIGS. 6-8, the inner convolution  60  of the spring  53  is engaged by an axle element  61 , shown in FIG.  8 . The axle element is inserted into the windup reel from one side, and a projecting shaft portion  62  thereof extends entirely through the assembly, and through an opening (not shown) in the circular flange  52 , which opening closely fits around the shaft projection  62 . The shaft section  62  joins with a cylindrical bearing portion  63 , which is of a diameter corresponding to that of an opening  64  in the circular flange  57  of the windup reel. A pair of opposed spring-engaging cleats  65  extend axially from the bearing  63 , in spaced relation to the shaft  62 . When the axle  61  is inserted into the assembled windup reel, the projecting shaft  62  passes through a bight  66  formed by the inner convolution of the spring  53 , and the end of the spring is received in the space between the shaft  62  and the cleats  65 . This locks the inner convolution of the spring against rotational movement relative to the axle  61 . 
     When the axle  61  is inserted into the assembled windup reel, the projecting ends of the cleats  65  engage the opposite flange wall  52  and serve as a position stop for the axle, allowing the shaft  62  to project an appropriate distance beyond the flange  52  and positioning the bearing  63  properly within the flange opening  64 . 
     As shown in FIGS. 3 and 5, the spaced walls  42  of the sled are formed with upwardly opening slots  70 ,  71  angled rearwardly of the front wall  35  of the sled. The slot  71  receives a projecting end of the shaft  62 , while the slot  70  receives a key  73  which projects outward from the bearing  63 . When the shaft  61  is in place, the assembly of the windup reel and shaft can simply be inserted into the slots  70 ,  71 , to mount the reel on the sled. The spring  53  can be pretensioned as desired by rotating the axle  61  before inserting the key  73  into the slot  70 . 
     As shown in FIG. 5, the lower portion of the windup reel  41  projects through the bottom wall  36  of the pusher sled, allowing the tension element  43  to extend forwardly, underneath any product items  21  positioned in a channel  23 . 
     In the operation of the system of the invention, the display tray  20 , shown in FIG. 1, is loaded with product items in the individual channels  23 , with each channel having a pusher sled  25  bearing upon the rearmost item  21 , urging the entire column forward. The RFID reader board  26 , which is located directly underneath the tray  20 , is activated periodically to read successively the individual columns of product items and report the identity of each individual item present. This enables the merchandiser to ascertain which items are selling and at what rate. Moreover, since each item is individually identified, the data feedback can indicate whether a given item is placed in the wrong column, so that the matter can be quickly corrected. 
     The non-metallic tension element  43 , which is interposed between the bottoms of the product items  21  and the reader board  26  positioned immediately below, does not in any way interfere with the transfer of information to the RFID reader. Although the windup reels  41  are driven by metallic springs  53 , these springs are positioned entirely behind the column of product items, and thus cannot interfere with accurate readings of product information. 
     In a modification shown in FIG. 9, the non-metallic tension element  80 , is in the form of a plastic monofilament line instead of a non-metallic tape. The monofilament is secured at one end to the windup reel  41  and attached at its free end to a toggle  81 . The operation of the windup mechanism and sled of FIG. 9 is the same as previously described. 
     In the alternative form of pusher sled  90 , shown in FIG. 12, a windup reel  91 , which can be constructed in a manner similar to the windup reel  41  heretofore described, is mounted in a recess  92  in the bottom wall  93  of the sled. An axle element  94  has its lower end (not shown) fixed in the bottom wall of the sled and serves the function of the axle  61  heretofore described, in locking an inner end convolution of an internal spring (not shown). A non-metallic tape  95  is wound on an outer drum surface of the windup reel  91  and carries a toggle element  96  at its forward end. The toggle element is secured in a forward portion of the display tray. In the case of the embodiment of FIG. 12, the toggle advantageously may be anchored in a vertical wall of the tray. When the non-metallic tape  95  is extended, the windup reel  91  is under spring tension and functions to urge the sled toward the anchored toggle, as will be understood. 
     In the alternative form of the sled  100 , shown in FIG. 13, a windup reel  101  is rotatably mounted on an axle  102  which is non-rotatably mounted on the bottom wall  103  of the sled. The construction of the windup reel  101 , and the function of the axle  102 , are as previously described, incorporating an internal windup spring tending to retrieve a non-metallic tape  104 , which is wound about an outer drum surface of the windup reel. A toggle  105  at the outer end of the tape  104  is arranged to be anchored in a forward portion of the display tray, preferably in a vertical wall thereof. 
     In the embodiment of FIG. 14, the windup reel  110  is mounted on an axle  111  which rotates with the spring  110 . The sled  112  is formed with three vertical walls  113 - 115  for rotatably supporting the windup reel  110  and its axle  111 . 
     The sled arrangement of FIG. 14 incorporates a helical spring  116 , which is external to the windup reel  110 . One end  117  of the spring is locked to a collar  118 , which is fixed to the shaft  111  and windup reel  110  for rotation therewith. The opposite end  119  of the helical spring is locked to the sled wall  115 . A non-metallic tape  120  is fixed to an outer drum surface of the windup reel  110  and extends through an opening (not shown) in the bottom of the sled or in the forward wall  121  of the sled. A toggle  122  at the forward end of the tape  120  is used to anchor the forward end of the tape at the front of the display tray. 
     As in the case of the other forms of sleds and windup reels, the spring  116  is pretensioned when the windup reel  110  is installed, such that the windup reel tends to fully retract the tape  120  and thus always tends to move the sled to a forwardmost position in the display tray  20 . 
     The present invention provides a unique and advantageous way for the utilization of product pusher sleds, in themselves well known and widely used, to a product display incorporating RFID inventory identification and control. This is accomplished by elimination of a conventional metal strip coil spring, normally used for the activation of product pusher sleds, and providing for activation of the sleds using non-metallic, flexible tension elements, which do not interfere with the necessary RF transmissions. 
     The arrangement of the invention greatly extends the usefulness of RFID technology in point-of-purchase display applications, which can now be usefully employed in any of the multitude of display presentations in which pushers are utilized or desired to be utilized. 
     The sled and windup reel arrangements provided by the invention enable the pusher mechanisms to be economically produced and installed, such that significant cost-to-benefit rations can be realized in extending RFID inventory management and control to product displays using product pusher devices. 
     It should be understood, of course, that the specific forms of the invention herein illustrated and described are intended to be representative only, as certain changes may be made therein without departing from the clear teachings of the disclosure. Accordingly, reference should be made to the following appended claims in determining the full scope of the invention.