Patent Publication Number: US-8985352-B2

Title: Modular merchandise display system

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation-in-part of U.S. application Ser. No. 13/268,203 filed on Oct. 7, 2011, and entitled “Modular Merchandise Display System”, the disclosure of which is incorporated herein by reference and on which priority is hereby claimed, which prior application is a continuation-in-part of U.S. application Ser. No. 12/932,162 filed on Feb. 18, 2011, and entitled “Modular Merchandise Display System”, the disclosure of which is incorporated herein by reference and on which priority is hereby claimed, which prior application is based on U.S. Provisional Application Ser. No. 61/338,408, which was filed on Feb. 18, 2010, and is entitled “Modular Merchandise Display System”, the disclosure of which is hereby incorporated by reference and on which priority is hereby claimed. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to merchandise display systems, and more specifically relates to merchandise display systems which are modular in function and which are free-standing or mountable to a wall. 
     2. Description of the Prior Art 
     Many conventional merchandise display systems include one or more parallel, vertically arranged, elongated support members which are spaced apart from one another. Each elongated support member may include a plurality of slots formed through its thickness and spaced apart axially along the length of the support member. The slots receive hooked ends of mounting brackets, which mounting brackets, when secured to the support members, extend perpendicularly to and outwardly from the front face of each support member. A tray or shelf extends between adjacent pairs of mounting brackets, and merchandise is displayed on, and supported by, the trays or shelves. The trays and shelves, with their associated mounting brackets, may be removed from their current location on adjacent support members and repositioned into different slots in the support members in accordance with the requirements of the merchandiser. 
     In order to reposition a shelf on such conventional merchandise display system, as described above, the shelf may have to be manipulated vertically (or horizontally) to disengage the mounting brackets on which the shelf rests from the elongated support members, and again manipulated vertically (or horizontally) to re-engage the mounting brackets to the support members when the shelf is repositioned. Such action, required to disengage the shelf and mounting brackets from the support members, may interfere with other shelves in close proximity to the shelf being repositioned and may necessitate the removal of other shelves adjacent to the one being repositioned. This problem is exacerbated if, rather than planar shelves or trays, rectangular parallelepiped or cuboidal modules situated one on top of another or situated side-by-side, with no space between modules, are used in the merchandise display system. Then, most probably all of the modules situated in a row or column may have to be removed in order to reposition a single module. 
     Additionally, the provision, and distribution of lighting throughout the retail environment, more specifically, on wall merchandising systems, often involves a massive amount of initial, and secondary, electrical work required on an ongoing basis. The advent of LED lighting in conjunction with low-voltage power options significantly reduces the amount of maintenance in such systems. 
     OBJECTS AND SUMMARY OF THE INVENTION 
     It is an object of the present invention to provide a merchandise display system which includes a quick release, front-loading mechanism for mounting individual shelves or modules used in the system. 
     It is another object of the present invention to provide a wall mountable, modular merchandise display system, where one module or a shelf of the display system may be easily removed without necessitating the removal of adjacent modules or shelves. 
     It is yet another object of the present invention to provide a wall mountable, merchandise display system having modules, trays or shelves which may easily lockingly engage or disengage from vertical support members of the system. 
     It is another object of the present invention to have a header signage element removable from the front of the module, without disassembling any peripheral components, to allow an alternative visual differentiation. 
     It is a further object of the present invention to provide a modular low-voltage electrical “grid” that can provide a safe, low voltage, stepped down from a standard 110 volt AC electrical power, to the merchandising system to allow for illumination in part, or the entirety, of the presentation unit, as well as for signage elements, RFID, sensing, scanning, Wi-Fi enabled, or dispensing, devices. 
     It is also an object of the present invention to provide an illuminated header mechanism that provides the ability to engage a secondary signage element that depends from the underside of the sign, and allows for expandable signage to be easily attached, and span any number of modules. 
     It is yet a further object of the present invention to provide an illuminated header sign on the modular merchandise system which utilizes an aluminum heat-sink, which supports an LED lighting element or elements, in conjunction with a U-shaped molded plastic header, to create a channel on the underside of the header to support a slide-in, removable, edge-lit signage panel. 
     It is yet a further object of the present invention to provide a merchandise display system which overcomes the inherent disadvantages of conventional merchandise display systems. 
     A merchandise display system constructed in accordance with one form of the present invention includes a frame which is free-standing or which may be fixed to an existing wall in an establishment, and a plurality of modules which are mountable on the frame directly from the front of the frame without requiring any manipulation of the modules either vertically or horizontally. The modular merchandise display system incorporates a unique method of attaching the modules to the frame, and incorporates a quick disconnect mechanism that allows the merchandiser or store planners to easily re-planogram the items of merchandise in an efficient, cost-effective manner. 
     The merchandise display system includes a plurality of metal or plastic modular “cubes” that snap onto a steel back wall of the supporting frame. The frame further supports an indexing system having vertical members, preferably made from injection molded plastic, to allow the modules to locate into a specific position from the front of the support frame. Each of the individual modules has insertable, retractable product trays, which may be extended from and retracted into the modules, to accommodate varying types of merchandise. The trays may be removed from the module by the store owner. 
     One of the advantages of the merchandising display system of the present invention is that an individual module (or tray) may be easily detached from the front of the support frame utilizing a spring-activated “trigger” mechanism located beneath the tray front, or may be the actual tray front, and a molded header sign. The molded header sign works in concert with the tray front. 
     In order to disengage an individual module from the frame, the spring-loaded header, which is mounted on the module, is depressed in a backward direction toward the frame, which allows the store owner to pull the tray front forward. When the tray is in such an extended position, locking wings, which had engaged the indexing members mounted on the frame, are opened to disengage the indexing members so that the complete module may be repositioned on the frame in another location or replaced by another module containing different items of merchandise. 
     In accordance with another form of the present invention, a merchandise display system includes a support frame on which are mounted two or more vertically disposed, spaced apart indexing members. The merchandise display system also includes a plurality of modules. The modules are mountable on the frame and selectively engage the vertical indexing members. Each module includes one or more trays which are slidably mounted within the module and which may be extended outwardly from the module so that a customer may select an item of merchandise resting on the tray. 
     Extending outwardly from the rear of each module is a pair of spaced apart pins. The pins are closely received in arcuate open recesses, or bores, formed in adjacent vertical indexing members when the module is mounted on the frame. The module further includes a pair of mutually inwardly biased, pivotable locking wings. The locking wings selectively engage the vertical indexing members when the module is mounted thereon. A release member, forming part of a release mechanism, situated within each module may be pulled (or pushed) to disengage the locking wings from the vertical indexing members of the frame in order to remove a module from the front of the merchandise display system without the need to remove adjacent modules from the system. 
     In yet another form of the present invention, a modular merchandise display system includes a frame and a plurality of merchandise supporting units. The frame has a pair of spaced apart, parallelly disposed indexing members. Each indexing member has an axial length, a thickness, a plurality of spaced apart openings formed through the thickness thereof and situated at least partially along the axial length thereof, and a plurality of spaced apart resilient locking clips situated at least partially along the axial length thereof. A respective locking clip is disposed in at least partial alignment with a corresponding opening formed in the indexing members. 
     Each merchandise supporting unit has a front side, a rear side situated opposite the front side, and at least a pair of spaced apart locator protrusions extending outwardly from the rear side thereof. The locator protrusions of each merchandise supporting unit include a recessed portion defining a recess. The locator protrusions are at least partially receivable in corresponding openings formed in each indexing member of the pair of indexing members and are engageable with corresponding resilient locking clips. The locking clips are receivable in the recesses of the locator protrusions when the merchandise supporting units are mounted on the frame to help secure the merchandise supporting units to the frame. Each merchandise supporting unit has a release mechanism to effect the disengagement of the merchandise supporting unit from the frame, the release mechanism including a release bar reciprocatingly slidably mounted on the merchandise supporting unit. The release bar has at least one free end, the free end being selectively engageable with a corresponding resilient locking clip to disengage the locking clip from a corresponding locator protrusion to effect removal of the merchandise supporting unit from the frame. 
     In yet another form of the present invention, the merchandise display system includes a plurality of metal or plastic modular “cubes” that snap onto rails of a steel back wall of the supporting frame. The “rail” frame&#39;s penetrations create an indexing system to allow the modules to locate into a specific position from the front of the support frame. Each of the individual modules has insertable, retractable product trays, which may be extended from and retracted into the modules, to accommodate varying types of merchandise. The trays may be removed from the module by the store owner. 
     Additionally, the modules can accept alternative snap-in interior components, other than trays, which include, but are not limited to, interior backwalls which allow for steel peghooks to be adjustably inserted, to allow for complete planogram flexibility, alternative signage elements, or illuminated product glorifier compartments. 
     One of the advantages of the merchandising display system of the present invention is that an individual module (or tray) may be easily detached from the front of the rear support frame utilizing a spring-activated “trigger” mechanism concealed behind a molded header sign. The molded header sign works in concert with a pair of rare earth magnets, which hold the header sign in the closed position, and serve to override the force of the two compression springs located at the ends of the U-shaped header, described previously, and conveying the low voltage electrical system to power the illuminated sign. 
     In order to disengage an individual module from the frame, the protruding legs of the magnetically held U-shaped header slide out from a pair of rectangular channels in the top of the side walls of the modular housing, which allows the store owner to pull the header forward. When the header is in such an extended position, it reveals a contoured “push-button” locking mechanism. Once this button is depressed, it disengages the indexing members so that the complete module may be repositioned on the frame in another location or replaced by another module containing different items of merchandise. 
     In accordance with another form of the present invention, a merchandise display system includes a support rail frame on which are mounted two or more vertically disposed, spaced apart indexing members. The merchandise display system also includes a plurality of modules. The modules are mountable on the frame and selectively engage the vertical indexing members. Each module includes one or more trays which are slidably mounted within the module and which may be extended outwardly from the module so that a customer may select an item of merchandise resting on the tray. 
     These and other objects, features and advantages of the present invention will be apparent from the following detailed description of illustrative embodiments thereof, which is to be read in connection with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a front perspective view of a portion of a merchandise display system constructed in accordance with one form of the present invention. 
         FIG. 2  is an exploded, front perspective view of the portion of the merchandise display system of the present invention shown in  FIG. 1 . 
         FIG. 3  is an enlarged front perspective view of a portion of the merchandise display system of the present invention shown in  FIGS. 1 and 2 . 
         FIG. 4  is a front perspective view of a merchandise display module constructed in accordance with the present invention for use with the merchandise display system of the present invention. 
         FIG. 5  is a front perspective view of the module shown in  FIG. 4  mounted on vertical indexing members forming part of the merchandise display system of the present invention. 
         FIG. 6  is a partially exploded, front perspective view of the module of the present invention shown in  FIGS. 4 and 5  for use with the merchandise display system of the present invention. 
         FIG. 7  is a partially exploded, front perspective view of a tray portion of the module of the present invention shown in  FIG. 4 . 
         FIG. 8  is a front perspective view of a main portion of the module constructed in accordance with the present invention for use with the merchandise display system of the present invention. 
         FIG. 9  is a cut away, front perspective view of the main portion of the module of the present invention shown in  FIG. 8 . 
         FIG. 10  is an exploded, front perspective view of the main portion of the module of the present invention shown in  FIG. 8 . 
         FIG. 11  is a top perspective view of the lower portion of the module of the present invention and illustrating the release and latching mechanisms thereof. 
         FIG. 12  is a top plan view of the module of the present invention shown in  FIG. 4 , and illustrating its attachment to a support frame forming part of the merchandise display system of the present invention. 
         FIG. 13  is a top plan view of a portion of the module of the present invention shown in  FIG. 12 , with the top portion thereof cut away to facilitate an understanding of the invention. 
         FIG. 14  is an exploded, front perspective view of another form of a module for use with the merchandise display system of the present invention. 
         FIG. 15  is a front perspective view showing a pair of modules and the operation of the release mechanism to remove a module from the merchandise display system of the present invention. 
         FIG. 16  is a front perspective view of a merchandise display system constructed in accordance with another form of the present invention, and illustrating a module and vertical indexing members of the merchandise display system and how the module is mountable to the vertical indexing members. 
         FIG. 17  is a rear perspective view of the module of the present invention shown in  FIG. 16 . 
         FIG. 18  is an exploded, front perspective view of a portion of a merchandise display system constructed in accordance with another form of the present invention. 
         FIG. 19  is a front perspective view of the portion of the merchandise display system of the present invention shown in  FIG. 18 . 
         FIG. 20  is an exploded, front perspective view of a portion of a merchandise display system constructed in accordance with yet another form of the present invention. 
         FIG. 21  is a front perspective view of the portion of the merchandise display system of the present invention shown in  FIG. 20 . 
         FIG. 22  is a side view and related detailed views of portions of the merchandise display system of the present invention shown in  FIG. 21 . 
         FIG. 23  is an enlarged front perspective view of a top portion of the merchandise display system of the present invention shown in  FIG. 19 . 
         FIG. 24  is an enlarged front perspective view of the top portion of the merchandise display system of the present invention shown in  FIG. 23 , and illustrating the adjustability of the merchandise display system. 
         FIG. 25  is an exploded, front perspective view of a portion of a merchandise display system constructed in accordance with an alternative form of the present invention. 
         FIG. 26  is a front perspective view of the portion of the merchandise display system of the present invention shown in  FIG. 25 . 
         FIG. 27  is an exploded, front perspective view of a portion of a merchandise display system constructed in yet a further form of the present invention. 
         FIG. 28  is a front perspective view of the portion of the merchandise display system of the present invention shown in  FIG. 27 . 
         FIG. 29  is a front perspective view of a module constructed in accordance with the present invention and forming part of the merchandise display system of the present invention. 
         FIG. 30  is a partially exploded, front perspective view of the module of the present invention shown in  FIG. 29 . 
         FIG. 31  is another partially exploded, front perspective view of the module of the present invention shown in  FIG. 29 . 
         FIG. 32  is yet another partially exploded, front perspective view of the module of the present invention shown in  FIG. 29 . 
         FIG. 33  is a partially cut away, front perspective view of a portion of the module of the present invention shown in  FIG. 29 . 
         FIG. 34  is a front perspective view of a portion of the module of the present invention shown in  FIG. 29 . 
         FIG. 35  is another front perspective view of a portion of the module of the present invention shown in  FIG. 29 . 
         FIG. 36  is a partially exploded, front perspective view of portions of the merchandise display system of the present invention shown in  FIGS. 18 and 29 . 
         FIG. 37  is a rear perspective view of a portion of the module of the present invention shown in  FIG. 29 . 
         FIG. 38  is a top view of a portion of the module of the present invention shown in  FIG. 29  mounted on the portion of the merchandise display system of the present invention shown in  FIG. 18 . 
         FIG. 39  is a front perspective view of a portion of the module of the present invention shown in  FIG. 29 . 
         FIG. 40  is a partially exploded, front perspective view of the portion of the module of the present invention shown in  FIG. 39 . 
         FIG. 41  is a top plan view of a portion of the module of the present invention shown in  FIG. 29 . 
         FIG. 42  is a top perspective view of the portion of the module of the present invention shown in  FIG. 41 , and illustrating the operation of the module. 
         FIG. 43  is a front perspective view of the merchandise display system of the present invention shown mounted on a supporting wall in an establishment. 
         FIG. 44  is a front perspective view of yet another embodiment of the modular merchandise display system of the present invention, showing a module thereof disengaged from the supporting frame. 
         FIG. 45  is a front perspective view of the supporting frame of the modular merchandise display system of the present invention shown in  FIG. 44 . 
         FIG. 46  is a front perspective view of a portion of the supporting frame of the modular merchandise display system of the present invention shown in  FIGS. 44 and 45 . 
         FIG. 47  is a front perspective view of the embodiment of the modular merchandise display system of the present invention shown in  FIG. 44 , and illustrating a flexible substrate or board for holding a power cord for lighting the display system. 
         FIG. 48  is a top rear perspective view of the module of the modular merchandise display system of the present invention shown in  FIG. 44 . 
         FIG. 49  is a partially exploded, perspective view of the embodiment of the modular merchandise display system of the present invention shown in  FIG. 44 , and illustrating how the module thereof may be mounted on the supporting frame. 
         FIG. 50  is a rear perspective view of the embodiment of the modular merchandise display system of the present invention shown in  FIG. 49 , and illustrating the module mounted on the supporting frame. 
         FIG. 51  is a plan view of a blank from which the module of the modular merchandise display system of the present invention shown in  FIG. 48  may be formed. 
         FIG. 52  is an exploded, front perspective view of the embodiment of the components forming the module of the modular merchandise display system of the present invention shown in  FIG. 48 . 
         FIG. 53  is a partially exploded, front perspective view of the module of the modular merchandise display system of the present invention show in  FIG. 48 . 
         FIG. 54  is a front perspective view of the assembled module of the modular merchandise display system of the present invention shown in  FIG. 48 , and illustrating pusher trays received thereby. 
         FIG. 55  is a front perspective view of yet another embodiment of the module of the modular merchandise display system of the present invention, and illustrating the module being outfitted with merchandise hanging hooks. 
         FIG. 56  is a partially exploded, front perspective view of the module of the modular merchandise display system of the present invention shown in  FIG. 48 , and particularly illustrating a release bar used to disengage the module from the supporting frame. 
         FIG. 57  is a top plan view of the modular merchandise display system of the present invention shown in  FIG. 44 , and illustrating the module thereof secured to the indexing members of the supporting frame. 
         FIG. 58  is a front perspective view of a modular merchandise display system constructed in accordance with another form of the present invention. 
         FIG. 59  is a front perspective view of the modular merchandise display system of the present invention shown in  FIG. 58  having a plurality of merchandise modules mounted thereon. 
         FIG. 60  is an exploded, front perspective view of an indexing rail assembly of the modular merchandise display system of the present invention shown in  FIG. 58 . 
         FIG. 61  is a front perspective view of the indexing rail assembly, shown assembled, forming part of the merchandise display system of the present invention shown in  FIG. 58 . 
         FIG. 62  is a front view of the indexing rail assembly forming part of the merchandise display system of the present invention shown in  FIG. 58 . 
         FIG. 63  is a rear view of the indexing rail assembly forming part of the merchandise display system of the present invention shown in  FIG. 58 . 
         FIG. 64  is an exploded, front perspective view of a portion of the indexing rail assembly forming part of the merchandise display system of the present invention shown in  FIG. 58 . 
         FIG. 65  is an exploded, front perspective view of a portion of the indexing rail assembly forming part of the merchandise display system of the present invention shown in  FIG. 58 . 
         FIG. 66  is an exploded, front perspective view of a portion of the indexing rail assembly forming part of the merchandise display system of the present invention shown in  FIG. 58 . 
         FIG. 67A  is a partially exploded, side view of the merchandise display system of the present invention shown in  FIG. 58 . 
         FIG. 67B  is an exploded, front perspective view of the indexing rail assembly forming part of the merchandise display system of the present invention shown in  FIG. 58 . 
         FIG. 67C  is a partially exploded, front perspective view of the merchandise display system of the present invention shown in  FIG. 58 . 
         FIG. 68  is an exploded, front perspective view of a portion of the merchandise display system of the present invention shown in  FIG. 58 . 
         FIG. 69  is a side view of a portion of the merchandise display system of the present invention shown in  FIG. 58 . 
         FIG. 70  is a front perspective view of a merchandise module forming part of the merchandise display system of the present invention shown in  FIG. 58 . 
         FIG. 71  is a front perspective view of a plurality of merchandise modules mounted to the indexing rail assembly forming part of the merchandise display system of the present invention shown in  FIG. 58 . 
         FIG. 72  is a partially exploded, side perspective view of the merchandise module and indexing rail assembly forming part of the merchandise display system of the present invention shown in  FIG. 58 . 
         FIG. 73  is a top plan view of a merchandise module forming part of the merchandise display system of the present invention shown in  FIG. 58 . 
         FIG. 74  is a side view of a portion of the merchandise module forming part of the merchandise display system of the present invention shown in  FIG. 58 . 
         FIG. 75  is a partially cut away, side view of the merchandise module forming part of the merchandise display system of the present invention shown in  FIG. 58 . 
         FIG. 76  is a front perspective view of a portion of the merchandise module forming part of the merchandise display system of the present invention shown in  FIG. 58 . 
         FIG. 77  is a front perspective view of a partially assembled merchandise module forming part of the merchandise display system of the present invention shown in  FIG. 58 . 
         FIG. 78  is a partially exploded, front perspective view of a portion of the merchandise module forming part of the merchandise display system of the present invention shown in  FIG. 58 . 
         FIG. 79  is a partially exploded, front perspective view of the merchandise module forming part of the merchandise display system of the present invention shown in  FIG. 58 . 
         FIG. 80  is a front perspective view of a portion of the merchandise module forming part of the merchandise display system of the present invention shown in  FIG. 58 . 
         FIG. 81  is a partially exploded, front perspective view of the merchandise module forming part of the merchandise display system of the present invention shown in  FIG. 58 . 
         FIG. 82  is a front perspective view of a portion of the merchandise module forming part of the merchandise display system of the present invention shown in  FIG. 58 . 
         FIG. 83  is a transverse, cross-sectional view of a portion of the merchandise module forming part of the merchandise display system of the present invention shown in  FIG. 58 , showing the module in a latch state. 
         FIG. 84  is a transverse, cross-sectional view of a portion of the merchandise module forming part of the merchandise display system of the present invention shown in  FIG. 58 , showing the module in a release state. 
         FIG. 85  is an exploded, front perspective view of a portion of the merchandise module of the merchandise display system of the present invention shown in  FIG. 58 . 
         FIG. 86  is a partially exploded, front perspective view of the merchandise module forming part of the merchandise display system of the present invention shown in  FIG. 58 . 
         FIG. 87  is a front perspective view of a lighted header assembly of the merchandise module forming part of the merchandise display system of the present invention shown in  FIG. 58 . 
         FIG. 88  is a top plan view of the header assembly of the merchandise module forming part of the merchandise display system of the present invention shown in  FIG. 58 . 
         FIG. 89  is a bottom plan view of the header assembly of the merchandise module forming part of the merchandise display system of the present invention shown in  FIG. 58 . 
         FIG. 90  is an exploded, front perspective, partially cut away view of the header assembly of the merchandise module forming part of the merchandise display system of the present invention shown in  FIG. 58 . 
         FIG. 91  is an exploded, front perspective, partially cut away view of the header assembly of the merchandise module forming part of the merchandise display system of the present invention shown in  FIG. 58 . 
         FIG. 92  is a front perspective view of the lighted header assembly and signage connected thereto of the merchandise module forming part of the merchandise display system of the present invention shown in  FIG. 58 . 
         FIG. 93  is a rear perspective view of the header assembly of the merchandise module forming part of the merchandise display system of the present invention shown in  FIG. 58 . 
         FIG. 94  is a front perspective view of the merchandise module forming part of the merchandise display system of the present invention shown in  FIG. 58 . 
         FIG. 95  is a bottom plan view of the lighted header assembly of the merchandise module forming part of the merchandise display system of the present invention shown in  FIG. 58 . 
         FIG. 96  is a partially exploded, front perspective view of a portion of the merchandise module forming part of the merchandise display system of the present invention shown in  FIG. 58 . 
         FIG. 97  is a partially exploded, front perspective view of the merchandise module forming part of the merchandise display system of the present invention shown in  FIG. 58 . 
         FIG. 98  is a top perspective view of the lighted header assembly of the merchandise module forming part of the merchandise display system of the present invention shown in  FIG. 58 . 
         FIG. 99  is a front perspective view of the header assembly shown in  FIG. 98  of the merchandise module forming part of the merchandise display system of the present invention shown in  FIG. 58 . 
         FIG. 100  is a partially exploded, front perspective view of the merchandise module forming part of the merchandise display system of the present invention shown in  FIG. 58 . 
         FIG. 101  is a partially cut away, front perspective view of a portion of the merchandise module forming part of the merchandise display system of the present invention shown in  FIG. 58 . 
         FIG. 102  is an enlarged, partially cut away, front perspective view of a portion of the merchandise module forming part of the merchandise display system of the present invention shown in  FIG. 58 . 
         FIG. 103  is a partially cut away, side view of the merchandise module forming part of the merchandise display system of the present invention shown in  FIG. 58 . 
         FIG. 104  is a bottom perspective view of a portion of the merchandise module forming part of the merchandise display system of the present invention shown in  FIG. 58 . 
         FIG. 105  is a top perspective view of a portion of the merchandise module forming part of the merchandise display system of the present invention shown in  FIG. 58 . 
         FIG. 106  is a partially cut away, bottom perspective view of a portion of the merchandise module forming part of the merchandise display system of the present invention shown in  FIG. 58 . 
         FIG. 107  is a partially cut away, side view of a portion of the merchandise module forming part of the merchandise display system of the present invention shown in  FIG. 58 . 
         FIG. 108  is a front perspective view of a portion of the merchandise module forming part of the merchandise display system of the present invention shown in  FIG. 58 . 
         FIG. 109  is a partially cut away, side view of a portion of the merchandise module forming part of the merchandise display system of the present invention shown in  FIG. 58 . 
         FIG. 110  is a partially exploded, rear perspective view of the merchandise module forming part of the merchandise display system of the present invention shown in  FIG. 58 . 
         FIG. 111  is a partially exploded, front perspective of the merchandise module forming part of the merchandise display system of the present invention shown in  FIG. 58 . 
         FIG. 112  is a partially exploded, rear perspective view of the merchandise module forming part of the merchandise display system of the present invention shown in  FIG. 58 . 
         FIG. 113  is a partially exploded, front perspective view of the merchandise module forming part of the merchandise display system of the present invention shown in  FIG. 58 . 
         FIG. 114  is a partially exploded, bottom perspective view of a portion of the merchandise module forming part of the merchandise display system of the present invention shown in  FIG. 58 . 
         FIG. 115  is a partially exploded, front perspective view of a portion of the merchandise module forming part of the merchandise display system of the present invention shown in  FIG. 58 . 
         FIG. 116  is a partially cut away, front perspective view of a portion of the merchandise module forming part of the merchandise display system of the present invention shown in  FIG. 58 . 
         FIG. 117  is a partially cut away, side view of a portion of the merchandise module forming part of the merchandise display system of the present invention shown in  FIG. 58 . 
         FIG. 118  is a partially cut away, front view of a portion of the merchandise module forming part of the merchandise display system of the present invention shown in  FIG. 58 . 
         FIG. 119  is a partially cut away, rear perspective view of a portion of the merchandise module forming part of the merchandise display system of the present invention shown in  FIG. 58 . 
         FIG. 120  is a partially cut away, side perspective view of a portion of the merchandise module forming part of the merchandise display system of the present invention shown in  FIG. 58 . 
         FIG. 121  is a partially cut away, side view of the merchandise module forming part of the merchandise display system of the present invention shown in  FIG. 58 . 
         FIG. 122  is a front perspective view of the release bar of the merchandise module forming part of the merchandise display system of the present invention shown in  FIG. 58 . 
         FIG. 123  is a rear perspective view of the release bar of the merchandise module forming part of the merchandise display system of the present invention shown in  FIG. 58 . 
         FIG. 124  is a partially cut away, side view of the latch bar and barbs of the merchandise module forming part of the merchandise display system of the present invention shown in  FIG. 58 . 
         FIG. 125  is a rear perspective view of the latch bar and barbs of the merchandise module forming part of the merchandise display system of the present invention shown in  FIG. 58 . 
         FIG. 126  is a front perspective view of the latch bar and barbs of the merchandise module forming part of the merchandise display system of the present invention shown in  FIG. 58 . 
         FIG. 127  is a side perspective view of the latch bar and barbs of the merchandise module forming part of the merchandise display system of the present invention shown in  FIG. 58 . 
         FIG. 128  is a partially cut away, rear perspective view of the latch bar and barbs of the merchandise module forming part of the merchandise display system of the present invention shown in  FIG. 58 . 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring initially to  FIGS. 1-3  of the drawings, it will be seen that a modular merchandise display system, constructed in accordance with one form of the present invention, includes a frame  2  made of steel or other structural material. The frame  2  includes a base  4  which rests on the floor of an establishment, vertical side pieces  6  attached to the base  4  and horizontal cross braces  8  attached to the vertical side pieces  6 . The frame  2  further includes a back wall  10 , formed of steel or other material, which is joined to the vertical side pieces  6  and horizontal cross braces  8 . The frame  2  may be free-standing on its base  4 , or may be situated adjacent to a wall or other vertical supporting structure and attached thereto by fasteners or the like for added safety. 
     A plurality of pairs of vertically disposed indexing members  12  is mounted on the front face of the frame  2  to the horizontal cross braces  8 . The pairs of indexing members  12  are spaced apart adjacent one another, and the indexing members  12  of each pair are also spaced apart from each other a predetermined distance. 
     Each vertical indexing member  12  is an elongated piece having opposite lateral sides  14 . The lateral sides  14  of a pair of indexing members  12  which face each other have formed therein a plurality of partial cylindrical or arcuate cuts or open recesses  16  formed adjacent to one another along the longitudinal length thereof. Thus, a particular arcuate recess  16  formed in one indexing member  12  of a respective pair of indexing members is in alignment with and faces an arcuate recess  16  formed in an adjacent indexing member  12  of the same pair of indexing members. Alternatively, each indexing member  12  may include bores (not shown), instead of arcuate recesses  16 , formed in the front face  18  thereof and extending at least partially through the thickness thereof. The indexing members  12  may be formed from an injection-molded plastic, metal or other material. 
     Although the frame  2  of the merchandise display system is described as including a base  4 , back wall  10 , vertical side pieces  6  and horizontal cross braces  8 , the system may be designed to cooperate with a pre-existing display frame  20  comprising the base  4 , back wall  10  (such as a peg board backing) and vertical side pieces  6 , as well as upper and lower horizontal support members  22 ,  24 , as shown in  FIG. 2 . The frame  2  of the present system, then, would include several horizontal cross braces  8  on which are mounted the vertical indexing members  12 . The top horizontal cross brace  8  may include a hook  26  running along the axial length thereof which engages the upper horizontal support member  22  of the pre-existing display frame  20 , and the bottom horizontal cross brace  8  would be affixed to the lower horizontal support member  24  using resilient clips  28 , as shown in  FIGS. 2 and 3 . 
     In one form of the present invention, and as shown in  FIGS. 4-13  of the drawings, the merchandise display system includes a plurality of modules  30 . Each module  30  is preferably in the shape of a rectangular parallelepiped or cuboid, that is, being box-like in shape. More specifically, each module  30  has a box-like main portion  31  which includes a top wall  32 , a bottom wall  34 , opposite lateral side walls  36  and, optionally, a rear wall or partial rear wall  38 , to define at least a four-sided enclosure having a front opening  40 . The module  30  may include one or more retractable trays  42  mounted therein. The trays  42  within the module  30  are provided for supporting merchandise thereon. The trays  42  may include slots  44  formed therein to receive dividers (see  FIG. 31 ) for partitioning items of merchandise. Each tray  44  is preferably slidably mounted to the lateral side walls  36  of the module  30  using conventional drawer slide mechanisms (not shown), and may be extended at least partially outwardly through the front opening  40  thereof so that a customer may easily select an item of merchandise displayed within the module  30  and supported on the tray  42 . The tray  42  is retractable within the module  30  through the front opening  40  thereof. The tray  42  is preferably formed from an injection-molded plastic, but may be formed of sheet metal or other material. 
     Each module  30  of the plurality of modules may include one pair, or more than one pair, of locator pins  46  extending outwardly from the rear side of the module  30 . Each pin is preferably situated near an opposite lateral side wall  36  of the module  30 , and the pins  46  are spaced apart from one another a predetermined distance. Adjacent vertically disposed, indexing members  12  are also spaced apart from each other a predetermined distance so that the pins  46  may register with and be at least partially closely received by the arcuate recesses  16  facing one another formed in adjacent indexing members  12  of a respective pair of indexing members. Thus, the modules  30  of the merchandise display system of the present invention may be loaded into the display system perpendicularly directly from the front of the frame  2 , where the rearwardly facing pins  46  of each module  30  engage corresponding arcuate recesses  16  formed in adjacent spaced apart indexing members  12  of the frame  2 . No manipulation of the module  30  either horizontally or vertically is required to reposition the module in a different location on the frame  2  and, accordingly, the modules  30  of the merchandise display system may be spaced closely to one another both vertically and horizontally and yet may be easily removed from and repositioned on the support frame  2 . 
     To ensure that each module  30  lockingly engages the indexing members  12  of the frame  2 , each module  30  includes at least one pair of pivotable locking wings  48 . Each locking wing  48  is pivotably mounted to the module  30  on the rear side thereof, and extends rearwardly on each module. Each locking wing  48  is structured to define a recess or pocket  50  on a lateral side thereof. More specifically, the recess  50  of one locking wing  48  of a respective module  30  is formed so that it faces the recess  50  of the other locking wing  48  of the same module  30  and so that one locking wing  48  is structured as the mirror image of the other locking wing  48 . 
     The locking wings  48  of each module  30  are biased by springs  52  or other means towards each other so that they extend substantially parallel to one another rearwardly of the module  30  on which they are mounted, but are pivotable laterally outwardly, away from each other, when the module  30  is being mounted onto adjacent indexing members  12  of a respective pair of indexing members. Each locking wing  48  includes a free end  54  having a leading, laterally outwardly sloping camming surface  56  situated adjacent to and outwardly from the recess or pocket  50  formed in the locking wing  48 . 
     When a module  30  is being mounted on the frame  2 , the spaced apart pins  46  of the module  30  are aligned with corresponding arcuate recesses  16  (or bores) formed in the indexing members  12 , and the module  30  is pushed toward the front face of the frame  2 , with the pins  46  registering with certain arcuate recesses  16  of the indexing members  12 . The non-facing, opposite lateral sides  14  of the indexing members  12  contact the camming surfaces  56  of the locking wings  48 , spreading the locking wings apart from one another against the bias of the springs  52 . As the module  30  is continued to be pushed into the frame  2 , the indexing members  12  move past the camming surfaces  56  of the locking wings  48  and are securely received by the pockets or recesses  50  formed therein. The locking wings  48 , which are biased in a direction towards one another, close about the pair of indexing members  12  so that the locking wings  48  partially surround portions of the non-facing lateral sides  14  of the indexing members  12 . With the pins  46  registered with selected arcuate recesses  16  of the indexing members  12  and the locking wings  48  closely engaging the lateral sides  14  of the indexing members, the product module  30  is now securely mounted to the frame  2  of the merchandise display system. 
     Each module  30  includes a release mechanism to allow the store owner to remove a module from the frame  2  of the merchandise display system. As can be seen from  FIG. 11  of the drawings, the release mechanism includes an elongated release bar  58  which is mounted above the bottom wall  34  of the module  30  and below a plate-like frame  60  which, in turn, is situated below the lowest merchandise tray  42  in the module. The module frame  60  defines a tunnel  62  with the bottom wall  34  of the module  30  in which the release bar  58  may reciprocatingly slide. As can be seen from  FIG. 11 , each spring  52  for biasing the locking wings  48  is secured at one end to the top surface of the module frame  60  and at its other end to an extended portion  64  of the locking wing  48  which is situated internally to the module  30  and on the opposite side of a pivot pin (not shown) by which each locking wing  48  is pivotally mounted on the module frame  60 . Thus, the release bar  58  reciprocatingly slides in the tunnel  62  of the module frame  60 , and has an exposed axial end  66  which extends beyond the front opening  40  of the module  30 . The exposed axial end  66  of the release bar  58  includes a tab  68  or opening  70  formed through its thickness which may be easily grasped by the store owner to remove a module  30  from the frame  2 . 
     The inner axial end  72  of the release bar  58 , situated opposite the exposed end  66 , includes a pair of spaced apart pins  74  extending upwardly from the upper surface of the release bar  58 . Each pin  74  is received by an elongated slot  76  formed in one end  78  of each of a pair of angled lever arms  80 . Each lever arm  80  includes a first segment  82  and a second segment  84  which is joined to the first segment  82  and disposed at an angle thereto. The opposite axial end  86  of each lever arm  80  is pivotally joined to the inwardly extending portion  64  of a respective locking wing  48 . Each lever arm  80  is pivotally mounted to the module frame  60  by a pivot pin  88  situated near where the first segment  82  is joined to the second segment  84 . 
     To remove a selected module  30  from the frame  2  of the merchandise display system, the store owner pulls outwardly, away from the front opening  40  of the module  30 , on the exposed end  66  of the release bar  58 . When the store owner pulls on the release bar  58 , the lever arms  80  pivot to force the locking wings  48  to open and disengage from a respective indexing member  12  against the bias of the spring  52  of each locking wing. The store owner may remove a module  30  from the frame  2  perpendicularly and outwardly from the front face of the frame  2 . The store owner pulls on the module  30  until the pins  46  disengage from the arcuate recesses  16  formed in the adjacent indexing members  12  of the respective pair of indexing members on which the module  30  is mounted. The module release mechanism, including the elongated release bar  58  and pivotable lever arms  80 , is contained substantially entirely within the module  30  and does not interfere with the closely spaced, adjacent modules  30  mounted on the frame  2 . 
     In an alternative version of the module  30 , as shown in  FIG. 7 , the module includes a UPC panel  90  and panel cover  92  situated underneath the merchandise tray  42 . The UPC panel  90  and panel cover  92  are operatively joined to the release bar  58 . The store owner may pull on a tab  94  of the panel cover  92  extending outwardly from the front of the UPC panel  90  and tray  42 , which causes the UPC panel  90  and the release bar  58  affixed thereto to move outwardly of the module  30 , thereby releasing the locking wings  48  from their engagement with respective indexing members  12  of the frame  2 , in order to remove a particular module  30  from the frame  2 . 
     A further modification of the module  30  is shown in  FIGS. 14 and 15 . A resilient header piece  96  is mounted to the module  30  at the upper front portion thereof. At least a portion of the header piece  96  is made of a transparent material so that the store owner may display product information or other graphics on a sheet of material  98  situated behind the header piece  96  and viewable through it from the front of the module  30 . A graphics panel  98  may also be received behind and held in place by a clear or transparent side graphics holder piece  99  removably affixed to opposite side walls  36  of the module. The header piece  96 , because of its resiliency, may be deflected inwardly of the module  30  by the store owner to expose the underside of the UPC panel  90  of the module  30  situated directly above it. In this way, the store owner may insert his fingers behind the underside and downwardly protruding front lip  100  of the UPC panel  90  of the module  30  situated directly above the module having the header piece  96  he is deflecting so that he may pull outwardly on the UPC panel  90  in order to move the release bar  58  and disengage the module  30  from the support frame  2 . 
     It should be further noted from  FIGS. 14 and 15  that the module  30  includes a hook bar  102  situated near the top wall  32  thereof. The hook bar  102  includes a plurality of recesses  104  formed across the width thereof. One or more product hooks  106 , having downwardly bent rear end portions  108  which are receivable in corresponding hook bar recesses  104  selected by the store owner, may be positioned within the module  30 , with the opposite upwardly bent free ends  110  of the product hooks  106  extending toward the front opening  40  of the module. Merchandise may be displayed within the module  30  by being inserted over the free ends  110  of the hooks  106  and hung thereon for selection and removal therefrom by consumers. 
       FIGS. 16 and 17  illustrate another version of the modular merchandise display system of the present invention. In the cutaway view of the module  30  shown in  FIG. 16 , the tray  42  situated within the module  30  is designed to accept pusher modules (see  FIG. 29 ) which are spring loaded and exert pressure on a row of merchandise items standing upright in each pusher module, pushing the merchandise items towards the front of the pusher module and the tray  42 . An example of such pusher modules is shown in U.S. Pat. No. 6,105,791 (Chalson, et al.), the disclosure of which is incorporated herein by reference. A spring-loaded extendible and retractable front UPC panel  112 , similar to the UPC panel  90 , situated below the tray  42 , is operatively linked to the locking wings  48 , such as by being coupled to the release bar  58 , to disengage the locking wings  48  from the indexing members  12  by pulling outwardly thereon in much the same way as the release bar  58  and release mechanism of the prior embodiments shown in  FIGS. 1-15  operate. 
       FIGS. 18-42  illustrate a preferred form of a modular merchandise display system constructed in accordance with the present invention. The preferred form of the display system shown in these figures is similar in structure and function to the embodiments described previously and shown in  FIGS. 1-17 . 
     Referring initially to  FIGS. 18-28 , it will be seen that a modular merchandise display system constructed in accordance with the present invention includes a frame assembly  120 , a plurality of merchandise display modules  122  (shown in  FIGS. 29-43 ) mounted on the frame assembly  120 , and a back wall support assembly  124 . The frame assembly  120  may come in relatively narrow sections, such as about one foot in width, which may be mounted alone on the back wall support assembly  124 , as shown in  FIGS. 18 and 19 , or mounted on the back wall support assembly with other similarly structured frame assemblies  120  in a side-by-side arrangement, as shown in  FIGS. 20 and 21 . Each frame assembly  120  includes an upper horizontal cross member  126 , a lower horizontal cross member  128  and, optionally, one or more middle horizontal cross members  130  situated between the upper and lower horizontal cross members  126 ,  128 . Each frame assembly  120  further includes a pair of spaced apart, vertical, parallelly disposed indexing members  132  having formed therein a plurality of arcuate or U-shaped recesses or openings  133  extending along their lengths. The vertical indexing members  132  are joined to the upper horizontal cross member  126 , the lower horizontal cross member  128  and the one or more middle horizontal cross members  130 . 
     The back wall support assembly  124  preferably includes a planar, vertical back wall  134 , which may be formed of a solid sheet of material (e.g., plastic, metal, wood, pressed composition board or the like), or in the form of a pegboard having a multiplicity of holes and formed of a material such as described previously. The back wall support assembly  124  may also include a base  136  which rests on the floor of an establishment, vertical side pieces  138  attached to the base  136 , an upper horizontal cross member  140  and a lower horizontal cross member  142 . The back wall  134  is affixed to and supported by the vertical side pieces  138  and the upper and lower horizontal cross members  140 ,  142  of the back wall support assembly  124 . 
     The upper and lower horizontal cross members  126 ,  128  of the frame assembly  120  include a provision for removably mounting the frame assembly to the back wall support assembly  124 . As can be more clearly seen in  FIGS. 22-24 , the upper horizontal cross member  126  of the frame assembly  120  includes a horizontal rear wall  144 , a top wall  146  perpendicularly joined to the rear wall  144  and a cantilevered hook plate  148  extending downwardly from the top wall  146  and spaced from the rear wall  144 . Together, the rear wall  144 , top wall  146  and hook plate  148  define a U-shaped channel  150  running along the length of the upper horizontal cross member  126  of the frame assembly  120 . A preferably resilient pad  152 , having an exposed concave lower surface portion  154 , is affixed to the underside of the top wall  146  within the U-shaped channel  150 . 
     The upper horizontal cross member  140  of the back wall support assembly  124  includes a front wall  156 , a bottom wall  158  perpendicularly joined to the front wall  156 , and a frame support hook wall  160  extending perpendicularly upwardly from the bottom wall  158  and spaced from the front wall  156 . Together, the front wall  156 , bottom wall  158  and frame support hook wall  160  of the upper horizontal cross member  140  of the back wall support assembly  124  define a U-shaped channel  162 . 
     The upper free end of the frame support hook wall  160  preferably includes a bulbous bead  164  extending along the length the horizontal upper cross member  140  of the back wall support assembly  124 . The frame assembly  120  is removably attached to the back wall support assembly  124  by lifting the frame assembly so that the cantilevered hook plate  148  of the upper horizontal support member  126  of the frame assembly  120  passes over the frame support hook wall  160  of the upper horizontal cross member  140  of the back wall support assembly  124  and is received by the U-shaped channel  162  of the back wall support assembly&#39;s upper horizontal member  140 . The upper horizontal cross member  126  of the frame assembly  120  thus rests on the frame support hook wall  160  of the back wall support assembly&#39;s upper horizontal member  140 , with the frame support hook wall  160  being received by the U-shaped channel  150  of the frame assembly&#39;s upper horizontal member  126 , and the concave portion  154  of the resilient pad  152  resting atop the bulbous bead  164  of the frame support hook wall  160 . 
     To further ensure the attachment of the frame assembly  120  to the back wall support assembly  124 , the lower horizontal cross member  128  of the frame assembly  120  includes a locking clip  166  on its rear wall and extending along its length, the locking clip  166  defining an outwardly and downwardly extending surface that terminates in a lip  168 . The locking clip  166  has a depth (front to back) so that it is closely received by an upwardly extending front U-shaped channel  170  partially defined by an upwardly extending wall  172  of the lower horizontal cross member  142  of the back wall support assembly  124  which is spaced from the front surface of this cross member, the lip  168  bearing against the inner surface of this upwardly extending wall  172 . 
     As shown in  FIGS. 23 and 24 , the upper horizontal cross member  126  of the frame assembly  120  may be adjustably attached to the vertical indexing members  132  so that the spacing between the upper and lower horizontal cross members  126 ,  128  of the frame assembly  120  is adjustable to make sure the locking clip  166  is fully engageable with the lower horizontal cross member  142  of the back wall support assembly  124  and to ensure that the frame assembly  120  is properly mounted on the back wall support assembly  124 . To provide for such an adjustment, the upper horizontal cross member  126  of the frame assembly  120  may include vertically extending elongated slots  174  formed through its thickness which receive machine bolts or other fasteners  176  therethrough that are attached to the indexing members  132 , as shown in  FIG. 24 . 
     As also can be seen in  FIGS. 23 and 24 , each indexing member  132  of the spaced apart pair of indexing members of each frame assembly  120  includes inner and outer lateral sides  178 ,  180 , the inner lateral side  178  of one indexing member of the pair facing the inner lateral side  178  of the other indexing member of the pair, and with the outer lateral sides  180  facing away from one another. It should further be noted from  FIGS. 23 and 24  that the plurality of arcuate or U-shaped recesses  133  are formed on the outer, non-facing lateral sides  180  of the indexing members  132  of each frame assembly  120 , and that the inner, facing lateral sides  178  of the indexing members  132  include curved locking rails  184  extending outwardly from the inner lateral sides along the length of the indexing members  132 . As will be explained, the arcuate recesses  133  are provided for at least partially receiving locator pins or protrusions  186  formed on the modules  122  of the merchandise display system, and the locking rails  184  are provided for engagement with locking wings  188  also forming part of the modules  122 . 
       FIGS. 25-28  illustrate an alternative form of the display system of the present invention that is depicted in  FIGS. 18-21 . As mentioned previously, the back wall  134  could be a pegboard panel  190 . The back wall support assembly  124  could include the pegboard panel  190 , a base  192 , vertical side pieces  194  affixed to the base  190 , an upper horizontal back wall mounting member  196  and a lower horizontal back wall mounting member  198 . The pegboard panel  190  is affixed to the vertical side pieces  194  and to the upper and lower horizontal back wall mounting members  196 ,  198 . The vertical side pieces  194  include a plurality of slots  200  periodically spaced along their lengths. Each of the upper and lower horizontal back wall mounting members  196 ,  198  includes tabs  202  situated near their opposite axial ends and extending outwardly from the rear surfaces thereof. The tabs  202  hook into selected slots  200  on the vertical side pieces  194  to help hold the upper and lower horizontal back wall mounting members  196 ,  198 , and the pegboard panel  190 , in place on the vertical side pieces  194 . 
     Each of the upper and lower horizontal back wall mounting members  196 ,  198  defines a U-shaped channel  150 ,  162 , like those defined by the upper and lower horizontal cross members  140 ,  142  of the back wall support assembly  124  shown in  FIGS. 22-24  so as to receive the cantilevered hook plate  148  and locking clip  166  respectively of the upper and lower horizontal cross members  126 ,  128  of the frame assembly  120  described previously. However, in the pegboard panel embodiment shown in  FIGS. 24 and 28 , the upper and lower horizontal back wall mounting members  196 ,  198  shown in  FIGS. 25 and 26  may be respectively replaced with a pegboard upper back wall mounting member  204  and a pegboard lower back wall mounting member  206 . Each of the pegboard mounting members  204 ,  206  defines a U-shaped channel  150 ,  162  as described previously with respect to the mounting members  196 ,  198  shown in  FIGS. 25 and 26 , but further include a plurality of spaced apart pegs  208  extending outwardly from the rear surface thereof which are receivable in corresponding holes of the pegboard panel  190  selected by the user in order to mount the frame assembly  120  on the pegboard panel  190  of the back wall support assembly  124 . For this embodiment, the pegboard panel  190  is affixed to the vertical side pieces  194  secured to the base  192 , and to a horizontal top rail  210  extending between the vertical side pieces  194 . 
     Although in  FIG. 28  only one frame assembly  120  is depicted as being mounted on the back wall support assembly  124 , it should be realized that several frame assemblies  120  may be mounted on the back wall support assembly  124  next to one another, such as with the embodiment of the display system shown in  FIGS. 20 and 21 . 
     As described previously, the merchandise display system of the present invention includes a plurality of modules  122 . A preferred form of such modules  122  is shown in  FIGS. 29-42 . 
     As shown in  FIGS. 29-31 , the module  122  preferably includes a box-like module frame  212  which defines an interior area for displaying merchandise. The module frame  212 , as can be seen in  FIG. 32 , includes a top wall  214 , an opposite bottom wall  216 , and two opposite side walls  218  which are joined to the top and bottom walls  214 ,  216 . More specifically, the side walls  218  have a plurality of locking tabs  220  extending perpendicularly from the inner surface of each, which locking tabs  220  are received in corresponding slots formed in opposite lateral edge pieces  222  of the top and bottom walls  214 ,  216  to hold the module frame  212  together in a box-like shape. The module frame  212  includes a front opening  224  and an open or partially open rear side  226 . 
     Slidably mounted on the bottom wall  216  of the module frame  212  is a UPC panel  228 , and slidably mounted above the UPC panel  228  on the bottom wall  216  is an extendible and retractable tray  230 . Both the UPC panel  228  and the tray  230  extend partially from the module frame  212  through the front opening  224 . 
     The tray  230  includes a rear wall  232 , an opposite front wall  234 , two opposite side walls  236  and a floor  238 . The tray  230  also has one or more vertically disposed divider panels  240  extending from the tray floor  238 . 
     The divider panels  240  define compartments with the rear and front walls  232 ,  234 , and the side walls  236 , in which compartments are preferably housed product pusher trays  242 , such as those disclosed in the aforementioned U.S. Pat. No. 6,105,791. The tray  230  is extendible from the front opening  224  of the module frame  212  by the user so that new merchandise may be loaded into the pusher trays  242  carried on the tray  230 . 
     As can be seen in  FIGS. 31 ,  39  and  40 , the UPC panel  228  preferably is formed from two interlocking pieces, a front piece  244  having a clear plastic or transparent vertical front wall  246  having turned-in lateral edges  248  which define channels for holding a graphic display behind the transparent front cover or wall  246 , and a rear piece  250  substantially co-planarly joined to the front piece  244  via interlocking tongues  252  on the rear piece  250  being received by aligned slots  254  formed in the front piece  244 . 
     The rear piece  250  of the UPC panel  228  includes two upstanding resilient tabs  260  situated on the top surface of the panel, which tabs are received by, and can move reciprocatingly within, corresponding channels (not shown) formed on the underside of the tray  230 . The tabs  260  and tray channels allow the UPC panel  228  to be extended from the front opening  224  of the module  122  only a predetermined distance, in order to enable the user of the display system to more easily change the graphics of the UPC panel front cover  246 , but also to more easily allow the user to gain access to a release bar  262  situated underneath the UPC panel  228  when it is desired to remove the module  122  from the frame assembly  120  of the display system, as will be explained in greater detail. 
     The bottom edges of the side walls  236  of the tray  230  ride in channels  264  defined by the lateral side walls  218  of the module frame  212  and the lateral edge pieces  222  of the bottom wall  216  of the module frame. This structure allows the tray  230  to be extended from, and retracted into, the interior area of the module frame  212 , but it should be noted that the UPC panel  228  can be extended and retracted independently of the tray  230 . 
     If the tray  230  is not used in the module  122 , which is the situation shown in  FIG. 39 , when hooks are used on which products are hung rather than being placed on the tray, a UPC slide cover  256  is used in its place. The UPC slide cover  256  takes the place of the rear piece  250  of the UPC panel  228 . The slide cover  256  also has tongues  252  which are received by the slots  254  of the front piece  244  to interlock the slide cover  256  with the front piece  244  of the UPC panel  228 . The slide cover  256  rides on its lateral edges  265  in the same channels  264  in which the tray  230  would have ridden, and includes downwardly extending projections on its bottom side formed by elongated cutouts  266  through its thickness to maintain the UPC panel  228  coupled to the module frame  212  as the panel is moved in and out of the module front opening  224 . 
     Also, as can be seen in  FIGS. 29 ,  30  and  40 , the module  122  may further include a header assembly. The header assembly is formed of a front header piece  268 , a header hook bar  270  and a header hook bar slide  272 . The header piece  268  is co-planarly joined to a main body portion  274  of the header hook bar slide  272  by spaced apart tabs  276  formed on the hook bar slide  272  which lockingly engage with cooperating openings  278  formed in the rear plate  280  of the header piece  268 . A bottom piece  282  of the hook bar slide  272 , which extends perpendicularly from the rear of the main body portion  274 , is similarly joined co-planarly to the hook bar  270  with interlocking tabs  284  extending upwardly from the top edge and/or sides of the hook bar  270  and slots  285  formed in the lower edge of the bottom piece  282  of the hook bar slide  272 . 
     The hook bar  270  has a plurality of bores  286  formed therein and situated between adjacent divider walls  288  of a plurality of divider walls. The bores  286  are provided to receive the bent ends  290  of product holding hooks  292 . Adjacent divider walls  288  prevent lateral movement of a product holding hook  292  when it is received by a bore  286  situated between the divider walls. The product hooks  292  have bulbous free ends  294  situated opposite the bent ends  290  on which products may be hung. The hooks  292  are used to display merchandise in the module  122  in lieu of the tray  230 . 
     The header piece  268  preferably includes a transparent vertical front wall  296  joined to the front edge of the rear plate  280 . Like the UPC panel  228 , the front wall  296  has turned-in side edges  298  which define a channel for receiving graphics or printed material behind the front wall which can be seen through the transparent front wall  296 . 
     The hook bar slide  272  includes opposite lateral side walls  300  on which are situated slide tabs  302  turned inwardly of the hook bar slide to face each other. The slide tabs  302  are received in cooperating slots  304  formed in the opposite lateral edges of the top wall  214  of the module frame  212  so that the header assembly, including the front header piece  268 , the hook slide bar  272 , the hook bar  270  and hooks  292  mounted thereon, is suspended from the top wall  214  of the module frame  212  within the interior space or area thereof, and is extendible from the front opening  224  and retractable within the module interior space, so that a user may more easily add products to the exposed hooks  292 . 
     A coiled spring  306  affixed to the top wall  214  has its free end  308  attached to the header assembly so that the header assembly may more easily retract into the module frame  212  from an extended position under the bias of the spring  306 . 
     The mechanisms for locking the module to the frame assembly  120  of the merchandise display system, and for releasing the locking mechanism to remove the module  122  therefrom, will now be explained, and reference should be had to  FIGS. 32-42  of the drawings. The locking mechanism in this embodiment to be described is very similar in operation to the mechanism described previously and shown in  FIGS. 1-17  of the drawings. However, it should be noted that in the embodiment shown in  FIGS. 32-42 , the arcuate recesses  133  of the indexing members  132  are formed on the outside, non-facing lateral sides  180  of the indexing members  132 , and the locking wings  188  engage the indexing members  132  of a pair of indexing members on their inner, facing lateral sides  178 . 
     More specifically, the module  122  includes a pair of locking wings  188  pivotally mounted on the bottom wall  216  of the module frame  212  and extending upwardly therefrom and outwardly from the open rear side  226  of the module. The locking wings  188  are spaced apart from each other a predetermined distance so that they may engage the inner lateral sides  178  of corresponding indexing members  132  of a pair of indexing members. 
     Each locking wing  188  of the pair extends vertically from the bottom wall  216  of the module frame  212 , and has a main portion  310  that is structured to include a free end  312  having a leading, laterally outwardly sloping camming surface  314  facing away from one another, the camming surfaces  314  leading toward a more inwardly located hooked edge  316  and a recess or pocket  318  adjacent the hooked edge  316 . 
     Each locking wing  188  also includes an extended portion  320  situated at an angle to the main portion  310  thereof at the bottom of the locking wing  188  where it is pivotally joined to the bottom wall  216  of the module frame  212 . The extended portion  320  of each locking wing  188  is pivotally joined to a release bar  262  which is biased in a direction into the module by a leaf spring  322 , so that the release bar  262 , in turn, biases the locking wings  188  to turn in opposite outward directions so that they will engage the inner facing lateral sides  178  of the indexing members  132 . 
     As shown in  FIGS. 29 ,  36  and  37 , each module  122  includes a first set of adjacent locator protrusions  186  (also referred to herein as pins) situated on a first vertical rear extension segment  324  of the bottom wall  216  near one lateral side wall  218  of the module frame  212 , and a second set of adjacent locator protrusions  186  situated on a second vertical rear extension segment  326  of the bottom wall  216  near the other lateral side wall of the module frame. The locator protrusions  186  of the first and second sets have a shape which complements that of the arcuate recesses  133  of the indexing members  132  so that they may be closely received by two corresponding adjacent arcuate recesses  133  on the non-facing lateral sides  180  of each indexing member  132  of the pair of indexing members when the module  122  is mounted on the frame assembly  120  of the display system. 
     More specifically, when a module  122  is being mounted on the frame assembly  120 , the locator protrusions  186  of the module are aligned with corresponding arcuate recesses  133  formed in the indexing members  132 , and the module is pushed toward the front face of the frame assembly  120 , with the locator protrusions  186  registering with certain arcuate recesses  133  of the indexing members  132 . The locking rails  184  extending from the facing lateral sides  178  of the indexing members contact the camming surfaces  314  of the locking wings  188 , spreading the locking wings apart from one another against the bias of the spring  322 . As the module  122  is continued to be pushed into the frame assembly  120 , the indexing members  132  move past the camming surfaces  314  of the locking wings  188  until the hooked edges  316  of the locking wings engage the locking rails  184  of the indexing members  132 , the locking rails  184  further being received by the pockets or recesses  318  of the locking wings  188 . The locking wings  188 , which are biased in a direction away from each other, latch onto the indexing members  132  between the pair of indexing members. With the locator protrusions  186  registered with selected arcuate recesses  133  of the indexing members  132  and the locking wings  188  closely engaging the locking rails  184  of the indexing members  132 , the product module  122  is now securely mounted to the frame assembly  120  of the merchandise display system. 
     Each module  122  includes a release mechanism to allow the store owner to remove a module from the frame assembly  120  of the merchandise display system. As can be seen from  FIGS. 35 and 42  of the drawings, the release mechanism includes an elongated release bar  262  which is mounted above the bottom wall  216  of the module frame  212  and below the UPC panel  228 . The release bar  262  includes a narrowed front section  328 , and a widened rear section  330  joined to the narrowed front section  328 . The bottom wall  216  of the module frame  212  defines a tunnel  332  through which the narrowed front section  328  of the release bar  262  may move reciprocatingly and by which the release bar is held captive. The widened rear section  330  of the release bar  262  has its opposite lateral edges situated under corresponding ledges  334  raised from the top surface of the bottom wall  216  and extending over the opposite lateral edges of the widened rear section  330  of the release bar in a direction facing each other. Thus, the widened rear section  330  of the release bar  262  is also held captive under these ledges  334 , but is allowed to move reciprocatingly thereunder so that the release bar  262  may move on the bottom wall  216  of the module frame  212  reciprocatingly in a front-to-back direction. 
     The opposite rear corners of the widened rear section  330  of the release bar  262  are pivotally joined to the angled extended portions  320  of the locking wings  188 . Thus, when a user of the merchandise display system pulls on the release bar  262  in an outward direction, the locking wings  188 , because of their attachment to the release bar  262 , rotate towards one another in the direction of the arrows shown adjacent to the locking wings in  FIG. 42 . 
     A leaf spring  322 , as mentioned previously, is used to bias the release bar  262  in a direction into the module frame  212 . An upstanding clamp  336 , situated on the top surface of the release bar  262  at the middle rear portion of the widened rear section  330 , securely holds the middle of the leaf spring  322 . The opposite ends of the leaf spring  322  are loosely held in gaps defined by two vertical projections  338 ,  340  extending from the top surface of the bottom wall  216  of the module frame  212  at the leaf spring ends to hold the ends of the leaf spring  322  in place but allow the ends to move within the gaps defined thereby when the release bar  262  is pulled outwardly by the user of the display system. 
     The narrowed front section  328  of the release bar  262  includes a grasp opening  342  formed therein which defines a tab  344  between the opening  342  and the front edge of the release bar  262 . The opening  342  and tab  344  of the release bar  262  may be easily grasped by the store owner to remove a module  122  from the frame assembly  120 . 
     To remove a selected module  122  from the frame assembly  120  of the merchandise display system, the store owner pulls outwardly, away from the front opening  224  of the module, on the narrowed front end section  328  of the release bar  262 , which is situated under the UPC panel  228 . When the store owner pulls on the release bar  262 , the extended portion  320  of the locking wings  188  pivot to force the locking wings to open and disengage from a respective indexing member  132  against the bias of the leaf spring  322 . The store owner may remove a module  122  from the frame assembly  120  perpendicularly and outwardly from the front face of the frame assembly. The store owner pulls on the module  122  until the locator protrusions  186  disengage from the arcuate recesses  133  formed in the adjacent indexing members  132  of the respective pair of indexing members on which the module is mounted. The module release mechanism, including the elongated release bar  262 , is contained substantially entirely within the module  122  and under the UPC panel  228 , and does not interfere with the closely spaced, adjacent modules mounted on the frame assembly  120 . 
     As can be seen from  FIG. 43  of the drawings, a plurality of modules  30 ,  122  may be mounted on the frame  2 ,  120  in rows and columns and closely situated next to one another. Each module  30 ,  122  may be removed directly from the front of the frame  2 ,  120  without the need for tilting the module  30 ,  122  or disturbing adjacent modules. Thus, the display system of the present invention can provide a higher density of items of merchandise than conventional merchandise display systems. 
     Although the modules  30 ,  122  having one or more trays  42 ,  230  are described as being mountable on the frame  2 ,  120  of the modular merchandise display system of the present invention, it should be realized that the trays  42 ,  230  themselves may include the structure described previously for mounting the modules  30 ,  122  to the frame  2 ,  120 , including the locking wings  48 ,  188 , the locator protrusions (pins)  46 ,  186  and the components of the release mechanism, to releasably mount the trays  42 ,  230  directly to the frame  2 ,  120  of the display system, without the need to use the modules  30 ,  122  described herein, and such structure is envisioned to be within the scope of the present invention. 
       FIGS. 44-57  illustrate yet another modular merchandise display system  400  constructed in accordance with the present invention. As with previous embodiments, this further display system  400  includes a frame  402  and one or more generally rectangular display modules  404  that are removably mountable on the frame  402  in a direction perpendicular to the frame, as shown in  FIG. 44 . No tilting of the display module  404  is necessary to add or remove the module to or from the frame, and adjacent display modules need not be removed. 
     Like the other embodiments of the display system described previously and shown in  FIGS. 1-43 , the frame  402  of the display system  400  shown in  FIGS. 44-57  has at least two vertically disposed indexing members  406  affixed to the horizontal cross braces  408 . Furthermore, as with the other embodiments, the horizontal cross braces  408  permit the frame  402  of the present invention to be affixed to a pre-existing frame  402 . The hook  410  running along the axial length of the top horizontal cross brace  408  can engage similar or complementary structures of the pre-existing display system  400 . 
     Adjacent indexing members  406  are parallelly disposed and spaced apart from each other a predetermined distance so that one or more display modules  404  may be fitted on the pair of indexing members  406  and extend between them in a vertically stacked arrangement, as shown in  FIG. 44 . As can be clearly seen in  FIGS. 46 and 49 , each indexing member  406  of a pair of indexing members includes a front wall  412 , an inside lateral wall  414  affixed to and extending rearwardly perpendicularly from an inner edge of the front wall  412 , and an outside lateral wall  418  affixed to and extending rearwardly perpendicularly from an outer edge of the front wall  412  and spaced apart from the inside lateral wall  414 . Thus, for a pair of adjacent indexing members  406 , the inside lateral walls  414  face each other, whereas the outside walls  418  face in opposite directions of each other. 
     Each indexing member  406  has formed through the thickness of the front wall  412  thereof a plurality of rectangular openings  422  spaced apart along the vertical length thereof. As will be seen, these openings  422  are provided for receiving locator protrusions  424  and locking hooks  426  disposed on the display modules  404  for removably securing the display modules to pairs of adjacent indexing members  406 . 
     As further can be seen from  FIGS. 46 and 49  of the drawings, each indexing member  406  includes a plurality of resilient locking clips  428 . A plurality of locking clips  428  may be integrally formed from one or more sections or blanks of sheet metal, plastic  429  or the like, which sections are affixed to the inside surface of one of the lateral walls of the indexing members. 
     The locking clips  428  are formed to be spaced apart from one another and situated along the vertical length of the indexing members  406  within the space defined by the inside and outside lateral walls  414 ,  418  and the front wall  412 . The locking clips  428  are also particularly shaped, as will be explained, so that they extend outwardly from the lateral wall, either the inside wall or the outside wall,  414 ,  418  on which they are mounted and at least partially project into the space directly behind the openings  422  formed in the front wall  412  of the indexing members  406 . In this way, the locking clips  428  may resiliently engage the locator protrusions  424  and locking hooks  426  of a display module  404  mounted on the indexing members  406  of the display frame  402 . 
     As can be seen in  FIGS. 46 and 57 , each resilient locking clip  428  has a serpentine configuration and extends into the space defined by the inside and outside lateral walls  414 ,  418  and front wall  412  of each indexing member  406 , as mentioned previously. More specifically, each locking clip  428  includes a first segment  430  extending perpendicularly from the blank or section  429  from which one or more locking clips are formed, which section  429  resides against the inner surface of  432  one of the inside and outside lateral walls  414 ,  418  of the indexing member. In the exemplary embodiment shown in  FIG. 57 , the blank or section  429  resides against the inner surface  432  of the inside lateral wall  414 . The first segment  430  is bent toward the inside lateral wall  414  at an acute inside angle to define the second segment  434  of the locking clip  428 . The angled second segment  434  is then bent toward the outside lateral wall  418  to define the third or “catch” segment  436  of the locking clip  428 , and then the third, catch segment  436  is bent again in an opposite direction toward the inside lateral wall  414  at an acute inside angle to define a leading ramp-like, free end, fourth segment  438  situated at least partially behind and in alignment with a respective opening  422  formed in the front wall  412  of a corresponding indexing member  406 . The third, catch segment  436  and the angled, ramp-like free end fourth segment  438  define between them at their juncture an abrupt edge, also referred to herein as an exposed barb  440 , which, with the catch segment  436 , is used to help lock the display module  404  to the indexing members  406  of the frame  402 . With such structure, the locking clips  428  act as resilient leaf springs which may be biased inwardly, toward the inside lateral walls  414  of the indexing members  406 , against the force of the locator protrusions  424  and locking hooks  426  of the display modules  404 , as will be described in greater detail. 
     In the present embodiment shown in  FIGS. 44-57  of the drawings, the display frame  402  of the modular merchandise display system  400  may include structure that defines a channel  444  for routing a power cord behind the display modules  404 , if it is desired that the display modules  404  or portions of the display frame be illuminated. As may be seen from  FIGS. 46 ,  49 ,  50  and  57  of the drawings, an intermediate, generally U-shaped (in transverse cross-section) bracket  446  is situated between a pair of adjacent indexing members  406  and affixed vertically to the horizontal cross braces  408 . The bracket  446  includes a back wall  448  perpendicularly joined to opposite lateral walls  450 , the lateral walls being slightly bent perpendicularly toward each other in front to define front tabs  452  and between them an open front face  454  in communication with an interior channel  444  running the axial length of the bracket  446 . The channel  444  is provided for receiving axially therein an elongated, flexible substrate or board  458 . 
     Referring to  FIGS. 46 ,  47  and  57 , spaced apart along the axial length of the substrate  458  and periodically affixed to the substrate  458  is a plurality of resilient, arcuate wire guides  460  that face each other to define a gap  462  therebetween through which an electrical power cord  461  may be inserted and held in place, and routed along the length of the channel  444 . As mentioned previously, this electrical power cord  461  is provided if it is desired to illuminate portions of the display system  400 , such as the interior of the modules  404 . The power cord  461  is neatly dressed on the frame and hidden from view within the channel  444  and behind the display modules  404  mounted on the frame  402 . 
     The preferred overall shape of the display module  404  for this embodiment of the system  400  shown in  FIGS. 44-57  is rectangular, as in the case of the previously described embodiments shown in  FIGS. 1-43 , although merchandise trays  42  may be used instead of modules. The module  404  preferably includes a top wall  464 , a back wall  466  and a bottom wall  468 , and two opposite lateral (side) walls  470 . In this embodiment, and as shown in  FIGS. 51 and 52 , the top wall  464 , back wall  466  and bottom wall  468  (and preferably other components of the module) may be formed from a single, planar blank  471  of sheet metal or synthetic material, such as plastic, and then bent 90° at the adjoining edges of the walls to partially form the modules  404 . Then, the opposite lateral side walls  470  are affixed to the opposite lateral edges of the top, back and bottom walls  464 ,  466 ,  468  by having tabs  472  on the lateral walls  470  interlock with slots  474  on the top, back and bottom walls  464 ,  466 ,  468 , or vice versa, to hold all five walls  464 ,  466 ,  468  and  470  in place and to define the display module  404  with an open or partially open front face  478 , as shown in  FIGS. 54-56 . Forming the top wall  464 , back wall  466  and bottom wall  468  from a single sheet of plastic or metal simplifies the molding, manufacturing and assembly process for the modules  404  and display system  400  of the present invention. As with the other embodiments of the display system  400  described previously and shown in  FIGS. 1-43 , the display module of  FIGS. 44-57  can receive pusher trays  477  or hooks  481  (see  FIGS. 54 and 55 ) for holding and displaying merchandise within its interior space. 
     A view of the outer surface of the back wall  466  of the display module  404  is shown in  FIGS. 48 and 49 . As can be seen, on opposite lateral portions of the back wall  466  of the module  404  are situated one or more locator protrusions  424 , and at least one locking hook  426  (also situated on each lateral portion). As with previous embodiments of the display system  400 , the locator protrusions  424  are used to help locate and position the display module  404  on a pair of adjacent indexing members  406  of the display frame  402 . The locator protrusions  424  are particularly positioned on the back wall  466  of the display module  404  and protrude outwardly from the outer surface thereof so that each locator protrusion  424  is received by a corresponding opening  422  formed in the front wall  412  of an indexing member  406  in order to guide the display module  404  as it is being placed on the frame  402  of the system  400 . 
     Referring to  FIG. 49 , each locator protrusion  424  preferably has a recessed portion  479  on one of its lateral sides that extends almost to the free end, or nose,  483  of the protrusion, and a lip  485  situated in front of the recessed portion  479  and on the same side thereof, near the free end or nose  483  of the protrusion  424 , to define a recess or pocket  480  that is preferably relatively shallow. This recess  480  receives the angled abrupt edge, or catch barb  440 , of the locking clip  428  situated inwardly of the protrusion lip  485 , when the display module  404  is mounted on the indexing members  406  of the frame  402  and the module protrusions  424  are fully received by their corresponding indexing member openings  422 . As the display module  404  is being mounted on the indexing members  406  of the frame  402 , the nose  483  of each protrusion  424  engages the ramp-like, free end, fourth segment  438  of a corresponding resilient locking clip  428 , displacing it slightly sideways, until the catch barb  440  passes over the lip  485  of the protrusion  424  and is received by the recess  480  of the protrusion  424 , whereupon the clip  428  springs back into the recess  480  in the direction toward its unbiased state, as shown in  FIG. 50 . 
     The locator protrusions  424  of the display module  404  ensure that the module is properly mounted on the indexing members  406  of the frame  402 , and help secure the module  404  to the frame. The shape of the protrusions  424  also provides some resistance to the removal of the display module  404  from the frame  402 , which resistance may be overcome by a greater outward pulling force on the module  404  to disengage the locking clip  428  from the protrusion  424 . However, the display module  404  of the display system  400  shown in  FIGS. 44-57  further preferably includes locking hooks  426  and a cooperating release mechanism to securely but removably affix the display module  404  to the indexing members  406  of the frame  402 , just as similar components are provided in the embodiments of the display system  400  described previously and shown in  FIGS. 1-43  of the drawings. 
     More specifically, and as shown in  FIGS. 49 ,  50 ,  56  and  57 , and in particular  FIG. 54 , of the drawings, each display module  404  includes at least one, but preferably two or more, locking hooks  426  attached to and extending outwardly from the outer surface of the back wall  466  of the module  404 . Each hook  426  is formed generally as an L-shaped member, with a first leg  494  extending perpendicularly from the outer surface  492  of the back wall  466  of the display module  404 , and a second leg  496  situated on the remote, unconnected end of the first leg  494  at a 90° or other transverse angle to the first leg. This second leg  496  has an underside surface  500  which partially defines with the first leg  494  a space for receiving a portion of a corresponding locking clip  426  of an indexing member  406 . The locking hooks  426  are situated near the lateral side portions of the back wall  466  of the display module  404  and in line with the locator protrusions  424  so that the locking hooks  426 , like the locator protrusions  424 , may also be received by corresponding openings  422  in the front wall  412  of the indexing members  406  to engage resilient locking clips  428  located at the openings  422 . 
     When the display module  404  is being placed on the display frame  402 , the locator protrusions  424  are received by the openings  422  in the indexing members  406 , with the nose  483  of each protrusion  424  engaging the ramp-like, free end, fourth segment  438  to displace the locking clip  428  until the barb  440  is received over the lip  485  and into the shallow recess  480  of the protrusion  424 . Also, the locking hooks  426  are received by openings  422  in the indexing members  406  that are in alignment with the hooks  426 . The leading or front surface of each hook  426  may be curved, and engages the ramp-like, free end, fourth segment  438  of the corresponding locking clips  428  situated in alignment with the hooks  426 . The hooks  426  bias the resilient locking clips  428  to the side until the ramp-like, free end, fourth segment  438  and barb  440  of corresponding locking clips  428  ride over the second leg  496 , with the barb  440  of the locking clip  428  being received by the space defined by the locking hook  426 , and with the catch segment  436  of the locking clip  428  resting against the underside surface of the second leg  496  of the locking hook  426 , as shown in  FIG. 57 . In this manner, the display module is secured to the indexing members  406  of the frame  402  until intentionally released by the proprietor of the establishment in which the display system  400  of the present invention is situated. 
     Each display module  404  of this embodiment also includes a release mechanism  490 , as shown in  FIGS. 48 ,  49 ,  50 ,  53 ,  54 ,  56  and  57 . The release mechanism  490  in this embodiment is in the form of a generally U-shaped bar  506  which is mounted at least partially within one or more interconnected channels  508  formed in the outer surface of the top wall  464  of the display module  404 . The release bar  506  includes an intermediate section  510  which, as will be explained, is pressed inwardly of the module  404  by the store owner or employee to disengage the locking hooks  426  of the display module  404  from the locking clips  428  of the indexing members  406  of the display frame  402 . The intermediate section  510  of the release bar  506  extends at least partially across the top wall  464  of the display module  404 , preferably from lateral side to lateral side,  470  and is situated near the front open face of the display module  404  so as to be easily accessible by the store owner or employee. 
     In one preferred form of the present invention, the intermediate section  510  of the release bar  506  may be hidden behind a top panel  512  pivotally mounted across and in front of the upper front portion  514  of the top wall  464  of the display module  404 , which top panel  512  is used for carrying advertisements, price or product information or other information on a placard or paper sheet, as shown in  FIG. 53 . The store owner or employee would pivot downwardly (or upwardly, if so designed) the top panel  512  to expose and gain access to the intermediate section  510  of the release bar  506  through an opening  513  formed in the upper front portion  514 . 
     The release bar  506  also preferably includes a pair of side sections  516 , each of which is joined to and extends perpendicularly from a corresponding axial end of the intermediate section  510  and which extends in a direction from the open front face  478  of the display module  404  to the back wall  466  thereof. The free ends of the side sections  516  are preferably turned 180° back on itself partially along the length of the side sections  516  to form U-shaped end portions  526 . An upstanding wall  522  is situated between the main portion of the side section  516  and the turned back section to help guide the side sections  516  in their reciprocating movement within their respective channels  508 . Accordingly, the U-shaped end portions  526  of each side section  516  of the release bar  506  has a smoothly curved free end which engages the locking clip  528  to bias it away from contact with a locking hook  526  in order to release the display module  404  from the frame  402 , as will be explained below. Tabs or lands (not shown) extending from the outer surface of the top wall  464  of the display module  404  and over the channels, and portions of the release bar maintain the release bar  506  and its sections within their respective channels  508 , yet allow the release bar  506  to move reciprocatingly therein. Alternatively, a top plate (not shown) may be used to cover the top wall  464  of the display module  404  and the release bar  506  interposed therebetween. 
     To remove a display module  404  from the display frame  402 , the user of the display system presses on an exposed portion of the intermediate section  510  of the release bar  506 , causing the side sections  516  to move within their respective channels  508  outwardly of the back wall  466  of the module  404 . The U-shaped end portions  526  of the side sections  516  are particularly positioned to engage the ramp-like, angled, free end segments  438  of the resilient locking clips  428 . This action causes the catch segment  436  of the locking clip  428  to disengage from contact with the underside surface of the hook  488  such that the barb or angled edge  442  of the locking clip no longer projects into the space behind the underside surface  500  of the locking hook  526  and so that the second leg  496  of the hook is free of the locking clip  428 . 
     This allows the user to pull the display module  404  outwardly from the frame  402  using a force sufficient to disengage the protrusions  424  from their corresponding locking clips  428 . The release bar  506  is preferably biased by a spring (not shown) situated on the top wall  464  of the display module  404  so that the release bar  506  is biased to return to its initial position within the channels  508  when the user releases pressure on the intermediate section  510 . Also, the resilient locking clips  528  return to their unbiased position behind the corresponding openings  422  in the indexing members  406  to insure their engagement with the locking hooks  426  and locator protrusions  424  when a display module  404  is again placed on the display frame  402 . 
       FIGS. 58 and 59  illustrate another form of the modular merchandise display system constructed in accordance with the present invention. Referring initially to  FIG. 58 , it will be seen that the display system includes a frame  600  having a base  602  which rests on the floor of an establishment, vertical side pieces  604  attached to the base  602  and upper and lower horizontal cross braces  606 ,  608  attached to the vertical side pieces  604 . The frame  600  further includes a back wall  610 , formed of steel or other material, which is joined to the vertical side pieces  604  and the horizontal cross braces  606 ,  608 . Like one or more of the previously-described embodiments of the present invention, the frame  600  may be free-standing on its base  602 , or may be situated adjacent to a wall or other vertical supporting structure and attached thereto by fasteners or the like for added safety. 
     A light fixture  612  having a housing  614  which defines an internal cavity for receiving lighting elements, such as fluorescent tubes, and having an open bottom side  616 , may be supported above and in front of the back wall  610  by a pair of generally horizontal support members  618  mounted on the vertical side pieces  604 . The light fixture  612  is provided to direct light on the plurality of modules  620  supported by the frame and/or other components of the merchandise display system, as will be described in greater detail. 
       FIGS. 60-69  illustrate one rail assembly  622  of a plurality of rail assemblies of the modular merchandise display system of the present invention, which allows a plurality of trays or display modules  620  to be mounted on the system and removed easily therefrom. Each rail assembly  622  preferably includes an upper bridge member  624 , a middle bridge member  626  and a lower bridge member  628  that are preferably provided. The upper bridge member  624 , as can be seen from  FIGS. 66-68 , includes an upper hooked end  630  which rests on an upwardly protruding rail  632  of the upper horizontal cross brace  606 , which is generally U-shaped in cross-section along its horizontal, axial length. The lower bridge member  628  has a downwardly extending portion  634  which is received by the lower horizontal cross brace  608 , which is also generally U-shaped in cross-section along its horizontal, axial length to provide a track or slot in which the downwardly extending portion  634  resides. The middle bridge section  626  may be secured to the back wall using fasteners, such as screws or bolts, or the like. Each of the upper bridge member  624 , middle bridge member  626  and lower bridge member  628  is formed from an electrically insulative material, such as a thermoplastic, to maintain the electrical separation of the rails of the rail assembly  622 , as will be described in greater detail. 
     The hooked end  630  of the upper bridge member  624  may include an insert  635  of polypropylene or other anti-friction material where it engages the upwardly protruding rail  632  of the upper horizontal cross brace  606  to allow the rail assembly  622  to glide transversely on the upper horizontal cross brace  606  of the frame. Such structure facilitates the repositioning of the rail assemblies  622  on the frame  600  by an employee or owner of the retail establishment in which the display system of the present invention is used. 
     Each rail assembly  622  includes a pair of vertically disposed rails  636 , which define indexing members. The pair of rails  636  is mounted to opposite lateral side portions  638  of the upper bridge member  624 , the lower bridge member  628  and the middle bridge member  626 . As can be seen from  FIG. 66 , each rail  636  is preferably U-shaped in transverse cross-section and includes a front wall  640  and a pair of opposite inner and outer lateral walls  642 ,  644  joined generally perpendicularly to the front wall  640 . More specifically, the inner lateral walls  642  of a pair of indexing rails  636  face each other, while the outer lateral walls  644  of each pair of indexing rails  636  are non-facing. On one or both of the lateral walls  642 ,  644  of each rail  636  is formed several receiving slits  646  which are dimensioned to receive corresponding L-shaped brackets  648  formed in the opposite lateral side portions  638  of the upper bridge member  624 , the middle bridge member  626  and the lower bridge member  628  to secure the pair of rails  636  to the bridge members and form a unitary support system for a plurality of merchandise display trays or modules  620  to be mounted thereon. As can be seen also from  FIGS. 66-68 , the front wall  640  of each rail  636  of the pair of rails, defining indexing members, includes a plurality of openings  650  formed through the thickness thereof along all or at least a portion of the axial length of each rail. The openings  650  are provided to receive locator pins or protrusions  652  mounted on the merchandise module  620 , or tray, as will be described in greater detail. 
     One of the advantages of this particular embodiment of the modular merchandise display system of the present invention shown in  FIGS. 58-69  is its ability to provide electricity to each of the merchandise display trays or modules  620  mounted thereon. Thus, as can be seen in  FIGS. 60-65  of the drawings, the display system includes a power supply/converter unit  654  which is mounted between a pair of rails  636 . 
     More specifically, and as shown in  FIGS. 64 and 65  thereof, the power supply/converter unit  654  of the present invention includes a housing  656  from which extends an AC power cord  658  for connection to a wall or floor 110 volt AC power outlet in the retail establishment where the display system is to be located. On one side of the housing  656  of the power supply/converter unit  654 , one or more AC power outlets  660  are also provided to provide power to the power supply/converter units  654  of adjacent rail assemblies of the display system. 
     Each power supply/converter unit  654  includes a circuit, such as a transformer, to step down the 110 AC voltage provided to it to a lower voltage. The lower voltage is provided to a converter circuit within the unit  654 , which may be, for example, a full wave rectifier circuit and a filter circuit, to convert the stepped-down AC voltage to a safe, DC voltage for powering light emitting devices or other illumination devices on the frame  600  or the merchandise display trays or modules  620  mounted on the rails  636  of the frame. The power supply/converter unit  654  may include a power indicator lamp  662  mounted on one of its sides and connected to the internal electrical circuitry to indicate whether power is being provided to the unit  654 . 
     As can be seen from  FIGS. 64 and 65  of the drawings, the power supply/converter unit  654  includes two lateral side plates  664 , each having an exposed outer surface on which is situated a pair of spaced apart, elongated bosses  666  and a resilient, leaf spring electrical contact  668  situated between the pair of bosses  666 . The pair of bosses  666  on each opposite lateral side plate  664  is received by a pair of corresponding slots  670  formed in the inner lateral walls  642  of the pair of indexing rails  636 , and each resilient contact  668  is received by an opening  672  formed in the inner lateral wall  642  of a corresponding rail  636  and situated between the receiving slots  670 . 
     When the power supply/converter unit  654  is inserted between the pair of indexing rails  636  so that corresponding bosses  666  are received by the slots  670  and the resilient electrical contacts  668  are received by corresponding openings  672  in the pair of rails  636 , the unit  654  is securely mounted between the indexing rails  636 , and each contact  668  will be in electrical communication with a corresponding rail  636  of a pair of rails. 
     More specifically, the resilient electrical contact  668  on one lateral side plate  664  of the power supply/converter unit  654  is provided with a positive (+) DC voltage, and the resilient electrical contact  668  on the opposite lateral side plate  664  of the unit  654  is provided with a negative (−) voltage, or ground, these voltages being provided to the contacts by the AC/DC converter circuit situated within the housing  656  of the unit  654 . Accordingly, one rail  636  of the pair of rails is electrified with a safe, low positive voltage, and the other rail  636  of the pair of rails is electrified with a safe, low negative voltage, or ground. Therefore, the pair of rails, now electrified, will provide a DC voltage to a merchandise display tray or module  620  mounted thereon and in electrical contact therewith. 
     A lighted merchandise display module  620  forming part of the display system of the present invention is shown in  FIGS. 70-128  of the drawings. As can be seen in  FIGS. 59 and 71 , a plurality of such modules  620  may be mounted on the indexing rails  636  and may be easily removed therefrom by activating the release mechanism on the modules and pulling on the module  620  in a direction normal to the frame  600  and indexing rails  636 , without the need to remove any adjacent modules  620  mounted on the indexing rails  636  or adjacent pairs of indexing rails either above or below, or on either side, of the module being removed. 
     Each display module  620  includes a top wall  674 , an opposite bottom wall  676 , and two lateral side walls  678  which are opposite from each other. Each module  620  further includes at least partial back wall  680  joined to the top, bottom and lateral side walls  674 ,  676 ,  678  (see  FIG. 81 ). Each of the walls  674 - 680  may be joined together by welding, fasteners or the like, or may be integrally formed from one sheet of metal or plastic and bent at fold lines at the junctures of adjacent walls. 
     As can be seen from  FIGS. 70 ,  85 ,  86  and  114 - 121 , the bottom wall  676  of the module  620  supports a removable merchandise pusher tray  682  for displaying merchandise thereon. Preferably, each merchandise pusher tray  682  includes pairs of upstanding divider walls  684 , and merchandise pusher elements  686  situated between the divider walls  684  of each pair. The pusher elements  686  are generally L-shaped members, formed of an interconnected vertical leg  688  and a horizontal leg  690 , having a coiled spring  692  mounted thereon. One end of each coiled spring  682  is affixed to the bottom wall  694  of the pusher tray  682 , within the confines of the divider walls  684  of each pair, and the other end of the coiled spring  692  is affixed to a respective pusher element  686 . 
     The horizontal leg  690  of the L-shaped pusher elements  686  includes a T-shaped rail  696  extending downwardly from the bottom surface thereof, which is received within a track, or elongated slot  698 , extending from the back toward the front of the bottom wall  69  of the tray  682 . The coiled spring  692  mounted on the pusher elements  686  biases the pusher elements towards the front of the tray  682  so that the pusher elements  686  exert pressure on any merchandise items situated in front thereof, that is, between the vertical leg  688  of the L-shaped pusher elements  686  and a partial, front wall  700  of the pusher tray  682 . 
     In a preferred form, and as shown in  FIGS. 115-121 , each pusher element  686  includes a pair or more of laterally spaced apart protruding walls  702  extending outwardly from the front surface of the vertical leg  688  of the L-shaped pusher element (see FIGS.  103  and  107 - 109 ). Each protruding wall  702  preferably has an angled front edge which is sloped upwardly and inwardly of the front surface towards the top free end portion of the vertical leg  688  of the L-shaped pusher element  686  such that each wall  702  extends outwardly from the front surface of the pusher element  686  to a greater extent at the bottom portion of the vertical leg  688  than at the top free end portion thereof. This slope of walls  702  not only facilitates the removal of merchandise items from between the pusher elements  686  and the partial front wall  700  of the tray  682 , but also tilts the merchandise items displayed in front of the pusher elements  686  backwardly so that light from the lighted header assembly  776 , which will be described in greater detail, on the module  620  will illuminate and brighten the front faces of the merchandise items that are viewable to a consumer. 
     The tracks, or slots  698 , in which the pusher elements  686  reciprocatingly slide include a portion  704  thereof with an enlarged width that is greater than the width of the T-shaped rail  696  of the pusher element  686  so that the pusher elements may be removed from between the divider walls  684  and replaced with a different pusher element, perhaps having a taller vertical leg  688  (see  FIGS. 105 and 106 ). 
     Also, the partial front wall  700  of the tray  682  includes U-shaped cutouts  706  formed through the thickness thereof in alignment with the pusher elements  686  so that merchandise items situated in front of the pusher elements  686  may be easily grasped by a shopper in the retail establishment by using his or her fingers through the U-shaped cutouts  706 . 
     The pusher tray  682  also preferably includes a slide out lower tray  708  mounted thereon, as more particularly shown in  FIGS. 103-109 . More specifically, the slide out lower tray  708  includes a bottom plate  710 , and a short, double-walled front panel  712  mounted perpendicularly on a front edge of the bottom plate  710 . The short front panel  712  defines a channel  714  running between the lateral sides of the slide out tray  708 . This front channel  714  includes an open top side  716  so that a placard or strip of paper or plastic may be inserted therein, residing in front of each of the pusher elements  686 , with indicia thereon to identify the merchandise held by the tray  682 . 
     Each lateral side portion of the bottom plate  710  of the slide out lower tray  708  includes a slot  718  formed through the thickness thereof to define partially inwardly resilient edge legs  720 , each leg  720  having a free end  722  and a pin  724  extending outwardly from each leg  720  in opposite directions. Opposite lateral side walls  726  of the pusher tray  682 , which extend downwardly from the bottom wall  694  thereof, include a pair of generally parallel upper and lower flanges  728 ,  730 , which define a slot or track  732  therebetween in which each pin  724  of the slide out lower tray  708  may reciprocatingly slide (see  FIG. 107 ). The front portions of the upper and lower flanges  728 ,  730  are curved slightly upwardly, and each lower flange  730  has a concave surface defining a partial pocket  734  (see  FIG. 107 ) in which the pin  724  can rest and pivot when the slide out lower tray  708  is pulled to its greatest extent outwardly from the front of the pusher tray  682 . 
     When the slide out lower tray  708  is fully received within the slot or track  732 , defined between the upper and lower flanges  728 ,  730  over the rear portion of the flanges, the lower edge of the upper flange  728  contacts the upper surface of the leg  720  on each lateral side of the slide out lower tray  708 , and the upper edge of the lower flange  730  contacts the lower surface of the leg  720  on each lateral side of the slide out lower tray  708 , so that the lower tray slides  708  out in front of the pusher tray  682  in a parallel direction with respect to the pusher tray. However, when the slide out lower tray  708  is extended from the front of the pusher tray  682  to where the upper and lower flanges  728 ,  730  are curved upwardly, and the pins  724  are received within the concave partial pockets  734  formed in the lower flanges  730 , the upper flanges  728  do not contact the lateral edge legs  720  of the lower tray  708  to allow the lower tray to pivot downwardly at an angle with respect to bottom wall  694  of the pusher tray  682 . This allows the owner or a worker of the retail establishment to easily replace the merchandise-identifying placard or paper strip received in the channel  714  of the front panel  712  of the slide out lower tray  708 , even for modules  620  which are mounted high on the frame  600  or indexing rails  636  of the display. 
     Towards the rear portion of the slot or track  732  in which each pin  724  of the slide out lower tray  708  reciprocatingly slides, there is an inwardly extending ramp protrusion  736  having an inclined surface protruding from the inside surface of each side wall  726  of the pusher tray  682  (see  FIG. 106 ). Because of the partial resiliency of the lateral edge legs  720  of the slide out lower tray  708 , an employee or owner of the retail establishment may push on the slide out lower tray inwardly toward the pusher tray  682 , so that the pins  724  ride over the inclined surface of the ramp protrusions  736  to rest in the rear end portion of the slot or track  732  situated past the inclined surface in order to retain the slide out lower tray  708  in a closed position on the pusher tray  682 , with the front surface of the front panel  712  being flush with the front surface of the partial front wall  700  of the pusher tray  682 . The owner or employee of the retail establishment need only exert a light pulling force on the slide out lower tray  708  to overcome the resistance provided by the ramp protrusions  736  on the pins  724  in order to extend the slide out lower tray  708  from the pusher tray  682 . 
     Preferably, a tab  738  is mounted on the front surface of the front panel  712  of the slide out lower tray  708  and extends outwardly therefrom to allow the owner or employee of the retail establishment to grasp the tab  738  to extend the slide out lower tray  708  from the pusher tray  682 . 
     The pusher tray  682 , with its slide out lower tray  708 , is removably mounted within the interior space defined by the merchandise module  620 , and rests on the upper surface of the bottom wall  676  thereof. Preferably, each lateral side wall  678  of the module  620  includes an inner plate  740  mounted against the inside surface thereof. The bottom edge of each plate  740  is spaced from the top surface of the bottom wall  676  to define a slot  742  between the plate  740  and the bottom wall  676  for receiving therebetween a respective side wall  726  of the pusher tray  682 . 
     A protrusion  744  extends outwardly from the inside surface of each lateral side wall  678  of the pusher tray  682 , and is positioned thereon a predetermined distance from the front wall  700  of the pusher tray  682 . The front edge portion  746  of the bottom wall  620  of the module is folded over itself to define a shoulder  748 . 
     When the pusher tray  682  is inserted into the merchandise module  620 , the lateral side walls  678  of the pusher tray are received within the slots  742  formed between the side wall plates  740  and the bottom wall  676  of the module, until the protrusions ride over the folded-over front edge portion  746  of the bottom wall  676  and rest thereon behind the shoulder  748  defined by the folded-over front edge portion  746  of the bottom wall  676 , thus maintaining the pusher tray  682  in place within the interior space defined by the merchandise module  620 . To remove the pusher tray  682  from the merchandise module  620 , the owner or employee of the retail establishment lifts the pusher tray  682  slightly so that the protrusions  744  are raised above the shoulder  748  defined by the folded-over front edge portion  746  of the bottom wall  676 . The pusher tray  682  may then be slid out of its receiving slots  742  on the side walls  678  of the module  620  and removed from the module. 
     The release mechanism for removing a module  620  from the indexing rails  636  of the display system will now be described. As in other embodiments, there are locator pins or protrusions  652  extending outwardly from the rear surface of the back wall  680  of each module  620 . These locator protrusions  652  are received in the openings  650  formed in the front wall  640  of the indexing rails  636 . Preferably, there are an upper pair  750  of locator protrusions  652  and a lower pair  752  of locator protrusions situated on each opposite lateral side portion of the back wall  680  of the module  620  and extending outwardly therefrom. Preferably, the protrusions  652  extend outwardly from rear plates  754  mounted on the outside surface of the back wall  680  of each module  620 . The protrusions  652  of each pair of the upper and lower pairs  750 ,  752  of protrusions  652  are spaced apart from each other, and the upper pair  750  and lower pair  752  of protrusions  652  are also spaced apart from each other, a predetermined distance so as to be in alignment with and be receivable by corresponding openings  650  formed in the indexing rails  636  of a pair of indexing rails of the display system. 
     Preferably, at least one locator protrusion  652  of each upper and lower pair of protrusions  750 ,  752  on each lateral side portion of the back wall  680  of the module  620  has an opening  756  formed in the bottom surface thereof and defines a cavity therein in which is mounted a movable latch barb  758 . The latch barbs  758  are affixed to and extend outwardly from a latch bar  760  which moves reciprocatingly and is held captive within a channel formed in each of the rear plates  754  affixed to the back wall  680  of the module  620 . Each latch bar  760  includes a molded leaf spring  762  extending outwardly therefrom on a top surface thereof, which leaf spring  762  engages an inside top surface of a respective rear plate  754  in which it is mounted (see  FIGS. 124-128 ). The leaf spring  762  biases each latch bar  760  downwardly so that the latch barbs  758  extend outwardly from the open side or opening  756  of the locator protrusions  652  in which they are mounted. The latch bar  760  may slide reciprocatingly, against the bias of the molded leaf spring  762 , within the channel formed in each respective rear plate  754 . Each barb  758  has an inclined surface  764  which is sloped outwardly from the free end of each of the particular locator protrusions  652  in which the barb  758  is mounted towards the back wall  680  of the module  620 , and ends in a shoulder  766  at the rear edge of the inclined surface  764  (see  FIG. 102 ). 
     When a module  620  is being mounted on the indexing rails  636  of the display system, the locator protrusions  652  are closely received by the openings  650  formed in the indexing rails  636 , and the edge of the front wall  640  of the indexing rails  636  which define the openings  650  engage the movable latch barbs  758  to force them inwardly of the open-sided locator protrusions  652  against the bias of the molded leaf spring  762  formed on each latch bar  740 . When the locator protrusions  652  of the module  620  are forced further into the openings  650  of the indexing rails  636 , the edge of the inclined surface  764  of the latch barbs  758  passes the edge of the rail openings  650  such that the latch barbs  758  are biased outwardly on the open side  756  of the locator protrusions  652  in which they reside by the molded leaf springs  762  of the latch bars  760 . The rear surface of the front wall  640  of the indexing rails  636  engages the shoulder  766  of each latch barb  758  so that the module  620  is secured in place on the indexing rails  636  of the display system until deliberately released. 
     Each lateral side wall  678  of the module  620  extends above the top wall  674  by a predetermined distance to define an extended portion  768  and a side flange  770  extending therefrom at a 90° angle inwardly of the module, which is raised above and overlies the outer surface of the main portion of the top wall  674  of the module  620 , thereby defining a U-shaped channel  772  on each opposite lateral side above the top wall  674  of the module (see  FIGS. 78-82 ). As will be described in greater detail, the channels  772  provided by the inwardly extending side flanges  770  receive corresponding legs of an illuminatable light bar assembly, also referred to herein as a header assembly  776 . 
     Also, the front portion of the top wall  674  of the module  620  is bent into an L-shape so that it includes a vertical extended portion  778 , and a front flange  780  attached to the vertical extended portion  778  and extending therefrom at a 90° angle so that it is raised above the outer surface of the main portion of the top wall  674  of the module, again to define a U-shaped channel  782 . 
     The top wall  674  of the module  620  also includes two spaced apart, upwardly extending, vertically disposed tabs  784  extending normally from the outer surface of the main portion of the top wall  674  of the module. Situated between the tabs  784  and the front edge flange  780  is a movable, module release push bar  786 , as will be described in detail below. 
     The release bar  786  is generally planar in shape and includes a main body  788  having a front wall  790 , a rear wall  792  situated opposite the front wall  790 , and two opposite lateral side walls  794 . Mounted on and extending outwardly from the front wall  790  of the main body  788  of the release bar  786  is a push bar extension piece  796 . The push bar extension piece  796  extends through an opening  798  formed through the thickness of the vertical extended front portion  778  of the top wall  674  of the module. The owner or employee of the retail establishment in which the display system is situated simply pushes inwardly on the push bar extension piece  796  to release the module  620  from the indexing rails  636  in order to remove the module. 
     A pair of leaf springs  800 , spaced apart from each other, extends outwardly from the front wall  790  of the main body  788  of the release push bar  786 . The front leaf springs  800  engage the inside surface of the vertical extended front portion  778  of the top wall  674  of the module. Similarly, a pair of spaced apart leaf springs  802  extends from facing inside surfaces of lateral side portions  804  of the main body  788  of the release push bar  786 . These rear leaf springs  802  are spaced outwardly from the rear wall  792  of the main body  788  of the release push bar  786 , and have free ends which engage the raised tabs  784  of the top wall  674  of the module. Thus, the module release push bar  786  is maintained in place between the spaced apart tabs  784  near the rear of the top wall  674  and the U-shaped channel  788  of the front edge portion of the top wall, and is reciprocatingly slidable on the outer surface of the top wall  674  therebetween. The front leaf springs  800  and the rear leaf springs  802  extending from the main body  788  of the release push bar  786  maintain the push bar in a particular position on the top wall  674  of the module, but allow reciprocating motion of the release push bar  786  on the top wall  674  of the module. 
     A leg  806  extends outwardly from each side wall  794  of the main body  788  of the release push bar  786  and rearwardly of the rear wall  792  thereof. Each side leg  806  includes an actuator ramp  808  having an inclined surface  810  which is received in a pocket  812  formed in the upper portion of each latch bar  760 , with the inclined surface  810  of the actuator ramp  808  engaging the inner surface of an upper wall of the latch bar  760  within the pocket  812  (see  FIGS. 101 and 102 ). 
     When a force is exerted on the push bar extension piece  796  inwardly of the module  620 , the main body  788  of the release push bar  786  moves rearwardly on the top wall  674  of the module, causing the actuator ramp&#39;s inclined surface  810  to engage the inside surface of the upper wall of each latch bar  760 . This motion causes each latch bar  760  to rise in its respective channel formed in the rear plates  754  mounted on the back wall  680  of the module (see  FIG. 84 ). In turn, the latch barbs  758 , attached to respective latch bars  760 , rise with the latch bar  760  and move inwardly within the cavity of the open-sided locator protrusions  652  in which they are mounted. As a result of such movement, the shoulders  766  on each latch barb  758  no longer engage portions of the indexing rails  636  surrounding the openings  650  in which the locator protrusions  652  are received, releasing the module  620  from the indexing rails  636  so that the module  620  may be pulled directly outwardly from the display system and removed therefrom. 
     When the push bar extension piece  796  is released, the rear leaf springs  802  on the release push bar  786  cause the main body  788  of the release push bar to retract to its normal position on the outer surface of the top wall  674  of the module  620 . The inclined surfaces  810  of the actuator ramps  808  are then withdrawn from the receiving pockets  812  of the latch bars  760 , thereby releasing upward pressure on the latch bars. The molded leaf springs  762  of the latch bars  760  are now free to bias the latch bars downwardly within the respective channels of the rear plates  754 , causing the latch barbs  758  to extend outwardly through the open sides  756  of their respective locator protrusions  652  (see  FIG. 83 ). 
     A lighted header assembly  776 , also referred to herein as a light bar assembly, is shown in  FIGS. 77-79  and  87 - 100 . The header assembly  776  is mounted on the upper portion of the module  620 , and extends in front of the inwardly bent front edge portion  814  defined by the vertical extended portion  778  and the front flange  780  of the top wall  674  and the push bar extension piece  796 . 
     The header assembly  776  includes a transverse section  816  and a pair of spaced apart legs  774  extending outwardly from the lateral end portions of the transverse section  816  at a 90° angle thereto. The transverse section  816  includes an upper wall  818  from which downwardly extends a transparent, L-shaped plastic or glass piece which defines an enclosure  820 . Within the enclosure  820 , and mounted on the lower surface of the upper wall  818 , is first, an elongated heat sink  822 , and second, adjacent to and in thermal communication with the heat sink  822  a printed circuit board  824  defining a light bar. The printed circuit board  824 , i.e., the light bar, includes a plurality of spaced apart light emitting devices  826 , such as light emitting diodes (LEDs), mounted thereto, as well as other electrical components, such as current limiting resistors  828 . When a current is provided to the light emitting devices  826 , they emit light through the transparent enclosure  820  to illuminate merchandise held within the module  620  on which the header assembly  776  is mounted. 
     At the free end of each leg  774  of the header assembly  776  is mounted a contact in the form of a coiled spring  830 . Each coiled spring contact  830  is connected by a wire passing through each respective leg  774  to the printed circuit board  824  defining the light bar. 
     As mentioned previously, each rail  636  of a pair of rails of the display system is energized or electrified with either a positive voltage or a negative voltage (or ground). As will be seen, when the module  620  is mounted on the indexing rails  636  of the display system, the coil spring contacts  830  of the header assembly  776  are compressed against and make contact with respective indexing rails  636  of a pair of rails so that the voltage on the rails  636  may be provided to the printed circuit board  824  defining the light bar of the header assembly  776  to provide power to and energize the light emitting devices  826  thereof. 
     As also mentioned previously, the legs  774  of the header assembly  776  are received within corresponding U-shaped channels  772  defined by the flanges  770  of the side walls  678  of the module  620  which overhang the top wall  674 . Each leg  774  is formed with a latch piece  832 , which extends outwardly from an inner lateral wall of each leg  774 , the latch piece  832  of one leg  774  facing the latch piece  832  of the other leg  774 . 
     Each latch piece  832  is formed as a relatively thin section of the leg that is spaced apart from the main portion  834  of the leg so as to be resilient and slightly movable, and biased outwardly from the main portion  834  of the leg  774  and inwardly of the module. The resilient latch piece  832  includes an inclined ramp segment  836 , followed by an abrupt shoulder  838  at the end of the inclined ramp segment  836 . The inclined ramp segment  836  is sloped inwardly of the module  620  in a direction from the free end portion of the leg  774  toward the transverse section  816  of the header assembly  776 . 
     When inserting the header assembly  776  into the U-shaped side channels  772  formed on the top wall  674  of the module, the opposite lateral edges  840  of the inwardly bent front edge portion  814  of top wall  674  engage the inclined ramp segments  836  of the legs  774 . The user forces the header assembly  776  into the leg receiving side channels  772  against the bias of the resilient latch pieces  832  until the inclined ramp segments  836  of the legs  774  pass the lateral edges  840  of the front edge portion of the top wall  674  and beyond the shoulders  838 . The resilient latch pieces  832  of the legs  774  are now free to extend outwardly from respective main portions  834  of the legs so that the header assembly  776  is captively retained on the upper portion of the module  620  until deliberately released. The shoulders  838  on each resilient latch piece  832  of the legs  774  act as stops to prevent the header assembly  776  from inadvertently being separated from the module  620  by the shoulder  838  abutting against the inside surface of the lateral edges  840  of the inwardly bent front edge portion  814  of the top wall  674 . 
     To remove the header assembly  776  from the module  620 , the user would grasp the legs  774  and squeeze the resilient latch pieces  832  thereof towards the main portion  834  of the legs  774  so that the shoulders  838  do not engage the lateral edges  840  of the inwardly bent front edge portion  814  of the module top wall  674 . Then, the legs  774  of the header assembly  776  may be retracted from their respective channels  772  and the header assembly  776  may be removed from the module  620 . 
     To insure that the header assembly  776  is properly mounted on the module  620  and so that the coil spring contacts  830  extend far enough beyond the back wall  680  of the module to contact the electrified indexing rails  636  of the display system, opposite lateral sides of the transverse section  816  of the header assembly  776  are formed with backwardly disposed shoulders  842  having exposed surfaces on which are mounted permanent magnets  844 . The magnets  844  contact the front surface of the inwardly bent front edge portion  814  of the top wall  674  of the module  620 . This front edge portion  814 , or all of the top wall  674 , and preferably all of the module  620 , is formed from sheet metal. Thus, the magnets  844  on the shoulders  842  of the transverse section  816  of the header assembly  776  come in contact with the front surface of the inwardly bent front edge portion  814  of the top wall  674  of the module so that the header assembly  776  is held in place by magnetic attraction on the module  620 , with the coil spring contacts  830  extending outwardly a sufficient distance from the back wall  680  of the module to contact the front wall  640  of the indexing rails  636  and receive power therefrom, which is provided to the light bar (printed circuit board  824 ) of the header assembly to power the light emitting devices  826  thereof. As stated previously, the light emitting devices  826 , when energized, illuminate the merchandise held by the module  620  through the transparent enclosure  820  of the header assembly. 
     The shoulders  842  of the header assembly  776  provide a space between the transverse section  816  of the header assembly and the release push bar extension piece  796  to allow the owner or employee of the retail establishment to easily grasp the push bar extension piece  796  with his fingers in order to remove a module  620  from the indexing rails  636  of the display system. 
     The header assembly  776  may be modified to include a slot for receiving signage. As shown in  FIGS. 90 ,  95  and  100 , the transverse section  816  of the header assembly  776  may include an inner wall  850  which defines at its lower end a slot  852  with the glass enclosure  820 . The slot may receive an upwardly extending tab  854  of a folded over, transparent plastic plate  856  which can receive and hold captive a placard, advertisement or sign  858 . Light from the light emitting devices  826  will shine on the signage  858  to illuminate it. 
     Alternatively, the header assembly  776  may have its enclosure  820  formed with a T-shaped slot (see  FIG. 91 ) to receive a T-shaped rail  862  mounted on the upper portion of a light transmissive glass or plastic plate  864  in light transmissive communication with the T-shaped rail  862 . The rail  862  and plate  864  act as a light bar, and light emitted by the light emitting devices  826  will enter the T-shaped rail  862  and pass therethrough and illuminate the plate  864  and any signage attached thereto or etched in the plate (see  FIG. 99 ). 
     Furthermore, and as shown in  FIG. 94  of the drawings, the enclosure  820  of the transverse section  816  of the header assembly  776  may have a channel or slot formed in its transparent front face so as to receive, and back illuminate, by the light emitting devices  826 , a placard, advertisement or signage  866 . 
     Additionally, and as shown in  FIGS. 96 and 97  of the drawings, the back wall of the module  620  may have mounted on the inside surface thereof a hanger plate  868 . The hanger plate  868  includes a plurality of slots  870  which may captively receive hanger rods  872 , if so desired by the owner of the retail establishment in which the display system of the present invention is used. The pusher tray assembly  682  may be removed from the module  620  and, instead, the hanger rods  872  may be inserted into the slots  870  in the hanger plate  868  so that merchandize items may be hung from the hanger rods  872  and displayed therefrom within the module  620 . 
     Although illustrative embodiments of the present invention have been described herein with reference to the accompanying drawings, it is to be understood that the invention is not limited to those precise embodiments and that various other changes and modifications may be effected herein by one skilled in the art without departing from the scope or spirit of the invention.