Abstract:
A method of forming a thermally insulated, transparent door for use on a reach-in merchandiser, in which said door has at least two glass lites, and which comprises providing a thermally and electrically insulating spacer member having an outer wall portion and an inner separator body portion, and forming angled notches in the separator body portion to define the respective corners of first and second glass lites; folding the spacer member at the angled notches around one of the glass lites with te body portion in surface contact with the inner glass lite surface and an edge flange of the outer wall portion in engagement with the adjacent marginal edge thereof, and bringing the free ends of the spacer member into juxtaposition and securing them together with locking means for holding the spacer member in assembled peripheral contact around the one glass lite; assembling another glass lite in surface contact with the body portion of the spacer member and in spaced relation with the one glass lite; and molding a non-metallic frame of a preselected polyurethane material to peripherally encase the assembled glass lites and spacer member and create an air-tight seal therebetween.

Description:
This application is a division of patent application Ser. No. 09/276,456 filed Mar. 25, 1999 for Reach-In Door For Refrigerated Merchandiser, now U.S. Pat. No. 6,148,563. 
    
    
     BACKGROUND OF THE INVENTION 
     (a) Field of the Invention 
     This invention relates generally to the commercial refrigeration art, and more particularly to improvements in glass front product merchandisers (so-called “reach-ins”) which hold and display medium and low temperature foods, including specifically doors for such reach-in merchandisers. 
     (b) Description of the Prior Art 
     Frozen food merchandisers are designed with the primary objective of maintaining product temperatures in the display area at about 0° F. for frozen food and −10° F. for ice cream, which in the past have required evaporator coil temperatures in the range of −10° F. down to −35° F. Medium temperature merchandisers maintain fresh product temperatures generally in the range of 30° F. to 40° F. 
     Multi-shelf reach-in merchandisers for storage and display of fresh and frozen food products (including ice cream) provide a generally vertical display of the product for greater visibility and product accessability to shoppers. In order to prevent the escape of cold air into the shopping arena, the display area of the merchandiser is closed by a glass front door. Glass is a poor thermal insulator so the doors are conventionally formed by two or three spaced apart panes of glass, defining one or two air spaces to increase the thermal insulation of the door. 
     The air spaces must be sealed for maximum insulating effect, and to prevent entry of moisture into these air spaces. Moisture in the air space condenses on the cold glass and obscures viewing of the product in the merchandiser. In the past, sealing of the air space has been accomplished by forming a an “insulating glass unit” or “IG unit” (sometimes called a “glass pack”) which consists of opposing glass panes (called “lights” or “lites”) separated by a metallic spacer secured by a suitable polymer (e.g., polysulfide, polyisobutylene, etc.). The glass pack is placed in a metal frame to complete the door. Thus, the door assembly process involves two separate steps of forming sealed air spaces, followed by forming a metal frame. Metal is most typically used in the frame and in the spacers because it has a good strength-to-weight ratio. In addition, metal is an excellent moisture barrier and when used as a spacer seals the air space from moisture for many years. However, metal has two important drawbacks when used in reach-in doors. The first is that metal is a poor thermal insulator, and the second is that metal is an excellent electrical conductor. 
     Conventional attempts to attenuate thermal conduction through the metal in the door generally involve placing barriers in the path of thermal conduction. Others have attempted to partially or entirely replace the metal frame with a polymeric material having a substantially lower thermal conductivity. Examples of such doors are shown in U.S. Pat. Nos. 5,097,642 and 5,228,240. However, it will be noted that in these prior art attempts to reduce the metal used in the doors have not eliminated the metallic spacers, nor have they replaced the need for sealing glass lites before forming the frame. 
     The electrical conductivity of metal is a hindrance because electrical power is used to heat one or more surfaces of the glass lites in the door. Heating is needed in order to prevent condensation from collecting and obscuring vision through the glass panes of the door. For instance, the moisture in the relatively warm ambient air of the store readily condenses on the outside of the door if it were not heated. Also, when the door is opened moisture condenses on the cold inside glass surface. Without heating, this condensation would not clear quickly and so the view of the product in the merchandiser would be obscured. Typically, heating is achieved by placing a semi-conductive film (e.g., tin-oxide) on the inner surface of the outer glass lite in the door. Bus bars along opposing edges of the lite provide an electrical potential causing a current to flow through the film and produce heat. It is presently necessary to keep the wiring and bus bars supplying the electric power carefully insulated and isolated from the outer metal door frame and the inner metal spacer. This means that a portion of the heating film had to be eliminated at the edge margin where there would be contact with metal. The primary danger occurs when a glass lite is shattered thus exposing the wiring to human contact and electrical shock. Conventionally, expensive electrical circuit breakers, such as ground fault interrupts and fused links, have been used to prevent accidental electrical shock in case of glass breakage. 
     SUMMARY OF THE INVENTION 
     The method of forming a thermally insulated, transparent door for installation and use on a reach-in merchandiser, in which said door has at least two glass lites and which comprises the steps of: providing a thermally and electrically insulating spacer member having an outer wall portion and an inner separator body portion, forming angled notches in the separator body portion to define the respective corners of first and second glass lites; folding the spacer member at the angled notches around one of the glass lites with the body portion in surface contact with the inner glass lite surface and an edge flange of the outer wall portion in engagement with the adjacent marginal edge thereof, bringing the free end of the spacer member into juxtaposition and securing them together with locking means for holding the spacer member in assembled peripheral contact around the one glass lite, assembling another glass lite in surface contact with the body portion of the spacer member and in spaced relation with the one glass lite, and molding a non-metallic frame of a preselected polyurethane material to peripherally encase the assembled glass lites and spacer member and create an air-tight seal therebetween. 
     A principal object of the present invention is to provide a method of making a reach-in door for a product display merchandiser which has door and casing improvements, better thermal insulation, better low-glare lighting, safer electrical isolation, secure door hinging and closure features and improved manufacturing. 
     A more specific object is to provide a method for a reach-in door having low thermal conductivity in which air spaces between glass lites of the doors are effectively sealed upon formation of the molded door frame. 
     Another object of the invention is to provide a method for a reach-in door which maintains a barrier to moisture entering the air spaces between glass lites. 
     Another object is to provide a method for a reach-in door which is more thermally insulated and therefore more energy efficient. 
     Another object is to provide a method for a reach-in door incorporating electrically insulating means simplifying the construction and installation of the door necessary to permit heating of one or more glass lites of the door and to reduce the risk of accidental shock in case of breakage of the lites. 
     These and other objects and advantages will become apparent hereinafter. 
    
    
     DESCRIPTION OF THE DRAWINGS 
     In the accompanying drawings which form a part of this specification and wherein like numerals refer to like parts wherever they occur: 
     FIG. 1 is an perspective view of a refrigerated reach-in merchandiser; 
     FIG. 2 is a fragmentary perspective view of reach-in doors and associated door casing of the merchandiser; 
     FIG. 3 is a greatly-enlarged fragmentary sectional view of a three lite reach-in door taken in the plane of line  3 — 3  of FIG. 2; 
     FIG. 4 is a fragmentary edge-on elevational view of a spacer member for the reach-in doors, laid out flat and showing a metal moisture sealing tape exploded above the spacer; 
     FIG. 4A is an enlarged view of a corner section of the spacer member configured for receiving a crossover electrical connector through the spacer; 
     FIG. 5 is a fragmentary perspective view from a corner of the spacer as installed on the glass lites, and partially exploded to illustrate the assembly of the spacer ends by an electrical plug-in and spacer locking key for the door; 
     FIG. 5A is a fragmentary perspective view from the opposite side from FIG. 5; 
     FIG. 6 is a side elevation of the electrical plug-in and spacer locking key of the spacer; FIG. 6A is a greatly enlarged fragmentary view of the electrical plug-in and spacer locking key taken from the right side of FIG. 6; 
     FIG. 7 is a fragmentary perspective view of an upper corner of a reach-in door partly broken away to illustrate an upper hinge reinforcement; 
     FIG. 7A is a fragmentary perspective view of a lower corner of the reach-in door partly broken away to illustrate a lower hinge reinforcement; 
     FIG. 8 is a fragmentary elevational view of the hinging margin of the reach-in door with parts broken away to reveal a torsion bar, as referenced by line  8 — 8  of FIG. 2; 
     FIG. 9 is a fragmentary elevational view of the upper corner of the reach-in door and door casing, with parts broken away to show details of construction; 
     FIG. 9A is a fragmentary elevational view of the lower corner of the reach-in door and door casing, with parts broken away to show details of construction; 
     FIG. 9B is a top plan view of a hinge plate as taken along line  9 B— 9 B of FIG. 9; 
     FIG. 10 is a fragmentary sectional view taken in the plane of line  10 — 10  of FIG.  8  and shows a torsion bar adjustment feature of the door; 
     FIG. 11 is a view of the spacer as assembled around the glass lites, and illustrates electrical conductors on the spacer; 
     FIG. 12 is a view of the spacer and glass lites from the side opposite to FIG.  11  and illustrates bus bars on the spacer; 
     FIG. 13 is a fragmentary sectional view of the spacer taken in the plane including line  13 — 13  of FIG. 12; and 
     FIG. 14 is a fragmentary perspective view of a bottom corner portion of the spacer and illustrates a crossover connector. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The present invention concerns improvements in reach-in merchandisers for medium and low temperature operation, and includes particularly improvements to thermal-type doors for such merchandisers and like temperature controlled enclosures. Referring to the drawings, and in particular to FIG. 1, a low temperature reach-in merchandiser is indicated generally at M for disclosure purposes. The merchandiser has an outer insulated cabinet having a front opening  11  (FIG. 2) defined by a cabinet casing C and closed by doors D hingedly mounted on the casing C. Multiple shelves  12  are selectively provided in the cabinet to hold and display product in the refrigerated interior product zone  13 . As shown in FIG. 2, the doors D are opened by handles H to access the refrigerated zone  13  inside the merchandiser where product is held for display. The refrigerated zone  13  is illuminated by lighting L mounted on mullions  14  of the door casing C. 
     The reach-in doors D of the present merchandiser are transparent and have a finished molded door frame F of a suitable material, such as a reaction injection molded polyurethane, and do not require a metal frame or covering of any type. In the preferred embodiment, the framing material is polyurethane which has low thermal conductivity for minimizing thermal losses through the door frame, in addition to which it molds with a smooth, hard, glossy or textured surface finish. Referring to FIG. 3, the low temperature door further includes three panes or lites G of glass, namely an inner lite  17 , a middle lite  18  and an outer lite  19  that are assembled and held together by the molded frame F. The precise number of lites may be other than described herein without departing from the scope of the present invention, but at least two lites would be used in the door. In an alternate embodiment, the middle lite is made of low-emissivity glass. A flexible magnetic strip holder  20  is attached to the frame F on an inside surface. The strip  20  has a continuous ridge  20   a  which is received in a channel  20   b  extending around the frame. Typical magnetic strips (not shown) are received in a pocket  20   c  of the magnetic strip holder  20 . As known, the magnetic strips  20   c  releasably attach to metal plates  20   d  on mullions  14  and other door casing members to seal the door D against the casing C when the door is closed. 
     The glass lites are held in parallel spaced apart, generally face-to-face positions relative to each other by a spacer S to form a basic glass panel subassembly preliminary to molding the frame F. Referring to FIGS. 3 and 4, the spacer is made of polypropylene, or other suitable material, which has low thermal and electrical conductivity. In a three lite door, two separator or spacer body portions  21  of the spacer S are inwardly disposed between adjacent pairs of the glass lites (i.e.  17 , 18  and  18 , 19 ), and these portions  21  are joined together by an integral, unitary outer wall portion  22 . The number of separator portions depends upon the number of glass lites to be spaced by the separator portions. Each separator or spacer body portion  21  has a generally D-shaped or rectangular configuration with spaced side walls  21   a  connected by a free inner wall  21   b  opposite to the outer wall member  22 . The side walls  21   a  are engaged in surface contact with respective glass lites ( 17 , 18  or  18 , 19 ) adjacent to the free edge margins  23  thereof. In addition, sealing lip  23   a  is provided along the juncture of the outward side wall and free wall ( 21   a , 21   b ) of each spacer body  21  as an additional assurance of continuous sealing engagement of the spacer bodies  21  with the respective inner surfaces  17   a , 19   a  of the outermost glass lites  17 , 19 . Continuous sealing contact of the spacer all the way around the lites is necessary to prevent molded material from encroaching the sealed air spaces  23   b  between adjacent lites during formation of the door frame F. The sealing lips  23   a , as shown in FIG. 3, are deflected from their at rest positions when the separator portions are installed between adjacent glass lites. 
     The planar-outer wall  22  forms one wall of each spacer body  21  and has a connecting web  22   a  between the spacer bodies and also projects laterally outwardly to form flanges  22   b  at the outer longitudinal edges of the spacer. The laterally projecting flange portions  22   b  abut against the outer peripheral edge margins  23  of the inner and outer lites  17 , 19  in the door for additional sealing and also to maintain the spacer in position under frame molding pressure. Still referring to FIG. 3, the spacer bodies  21  are hollow ( 24 ), but filled with a suitable material for trapping moisture, such as a desiccant  24   a  (e.g., activated alumina). The inner wall  21   b  of each spacer body  21  has suitable holes or slots  24   b  spaced along its length to permit any moisture inside the air spaces  23   b  between adjacent lites to enter the hollow interior  24  and be adsorbed by the desiccant. 
     Referring to FIGS. 4 and 4A, the spacer S is fabricated as a flat extruded strip with four angle-cut or chamfered notches  25  being formed in the spacer body  21  at locations corresponding to the four corners of the basic glass panel for the door D. The spacer S forms an outer peripheral covering for the three lites  17 ,  18 ,  19  by coming together at the corners (in the fashion of a miter joint) when the spacer is assembled around the lites so that the spacer segments extend continuously along the sides and mate together through the corners. The spacer S is constructed with five sequential segments identified in FIG. 4 as  26   a - 26   e , and being interconnected at the angle cuts  25  by the continuous outer wall  22 . Clearly, when the spacer S is folded or bent during assembly with the glass lites, the two alternate short segments  26   b  and  26   d  will be in opposed relation and form the short horizontal top and bottom walls of the panel. The long segment  26   c  will define the long vertical wall margin of the panel that will become the outer free handle margin of the door, and the two remaining segments  26   a  and  26   e  at the free ends  25   a  of the strip will close the inner hinged vertical margin of the panel, as now described. 
     The free ends  25   a  of the spacer strip S are joined together by a unique electrical plug-in and spacer locking key  30 , shown best in FIGS. 5,  5 A,  6 ,  6 A and  11 - 13 . The key  30  has a main assembly or locking body section  31 , and an electrical connector section  32  to be described later. The main body section  31  is constructed and arranged to mate with and join the free ends  25   a  of the spacer S, and it is configured with spaced separator body portions  31   a  and a connecting wall  31   b  with outer flanges to match the configuration of the spacer  21 . Connector blocks or keys  31   c  project longitudinally from both ends of the separator bodies  31   a , and these are sized to fit into the hollow cavities  24  of the spacer bodies  21  (FIGS. 5,  5 A and  6 A). In addition, the inner wall  21   b  of the spacer bodies  21  have an orifice  31   d  adjacent to their free edge  25   a , and each key  31   c  has a chamfered locking detent  31   e  to snap lock into these holes  31   d  and form a secure interlock therewith. The spacer S is free of a bonded seal connection to the respective glass lites  17 - 19  except through the final molded door frame F, as will be described. 
     An important feature of the invention is the moisture barrier tape  33  which is applied to the outer surface of the outer wall  22  and flange  22   b . This tape  33  may be an aluminum foil tape or, preferably, a thin, substantially non-metallic, moisture impervious polyester/polyethlene film that is electrically non-conductive. Referring to FIGS. 3,  4  and  5 , the tape  33  has a main body  33   a  that covers the entire outer wall  22  of the spacer S and has an edge wrap that extends around the outer flange segments  22   b  and, preferably, onto the adjacent outer surfaces of the inner and outer lites  17 , 19 . Thus, as shown in FIG. 4, the tape  33  may be provided as a unitary one-piece main body sheet  33   a  with integral edge wrap portions ( 33   b ) or as a series of main body sheets or segments corresponding to the five sections  26   a — 26   e  of the spacer strip  21 . The foil or film sheets  33   a  may be applied to cover the outer wall  22  throughout its length so that the outer spacer wall surface is covered before it is assembled with the glass lites  17 - 19 . In that event, the width of the tape or film would be only slightly greater than the width of the outer wall  22 . The tape may wrap around and under the flanges  22   b  and would be in contact with the peripheral edge of the outer lites  17 , 19  when installed. The electrical plug-in and locking key  30  is also covered with the same film or tape  33   c . The tape  33  provides a non-structural moisture barrier to inhibit significant transfer or migration of water vapor into the spaces  23   b  between the lites for many years. It is to be understood that other materials having the appropriate moisture barrier properties could also be used for the tape, in particular other films having moisture barrier and electrically non-conductive properties. It is possible to manufacture a door which has no such tape, but the lifetime of the door would be shortened by moisture ingress unless other materials for the spacers or the molded door frame with sufficiently low moisture permeability can be identified. 
     As indicated, the basic glass panel with assembled lites, spacer and moisture barrier tape is encased in the outer molded door frame F. As shown in FIG. 3, this frame F has a main body portion  35  that surrounds the periphery of the glass panel subassembly, and has an outer wall margin  35   a  and side walls  35   b  that extend inwardly and capture the outer glass surface margins ( 35   c ) of the inner and outer lites  17 , 19 . 
     The reach-in door D is mounted on the door casing C of the refrigerated merchandiser M for swinging motion between a closed position in which the door covers the encased front opening  11  in the cabinet  10  (center door in FIG.  2 ), and an open position for access to the refrigerated display zone  13  within the cabinet (left door in FIG.  2 ). Referring to FIGS. 7,  7 A,  9  and  9 A, the hinging means for mounting the door D are accommodated during the frame molding process by forming an upper cylindrical opening  38  receiving a metal sleeve or bushing  38   a  and a lower cylindrical opening  39  receiving a sleeve or bushing  39   a . After completion of molding the frame F around the glass lite subassembly, the upper bushing  38   a  preferably receives a plastic sleeve  38   b  (FIG. 9) in which an upper hinge pin  40  is slidably received for free turning movement so that this hinge pin is free of any fixed connection to the molded frame F. The bushing  38   a  contains a compression spring  40   a  which biases the pin  40  for vertical outward movement relative to the frame F so that the pin projects upwardly to be received into an opening  40   d  in an upper mounting plate  40   b  attached by bolts  40   c  to the door casing C of the merchandiser M (FIG.  9 B). The bolts  40   c  are received through respective elongate slots  40   e  located at offset positions in the upper mounting plate  40   b  and are secured into the casing C. The elongation of the slots  40   e  permits the upper mounting plate  40   b , and hence the position of the hinge pin opening  40   d  to be moved laterally from side to side on the door casing. In this way the pivot axis of the door D can be adjusted for optimum alignment within the casing opening. The pin  40  has a notch  40   f  sized to receive the end of a screwdriver for camming the pin downwardly into the sleeve  38   a ,  38   b  against the bias of the spring  40   a  and out of the opening  40   d  in the upper mounting plate for removing the door D from the merchandiser M. 
     The upper bushing sleeve  38   a  for the upper hinge pin  40  may be part of an upper reinforcing member  40   g  molded into the door frame (FIG.  7 ). The reinforcing member  40   g  is preferably a shaped metal plate or other suitable high strength structural material and the sleeve  38   a  is secured to it. The use of a reinforcing member  40   g  is to rigidify and strengthen the frame F in the region of the upper door mounting connection and permits forces on the door to be translated and distributed over a wider area of the molded frame F. The member  40   g  also provides a bearing portion ( 41   a ) to receive a pivot pin  41   b  to connect one end of a hold open bar  41  to the door. The hold open bar  41  limits the maximum angle of opening of the door relative to the merchandiser, and functions to hold the door fully open when needed (e.g., as for stocking the merchandiser). The left-hand door D is shown in its fully open position in FIG.  2 . The hold open  41  is pivotally connected to the casing C by a bolt  41   c  at a first end. Typically, the sliding pin is received in a slot near a second end of the hold open and slides along the slot as the door is opened and closed. A narrow neck (not shown) near the end of the slot separates a main portion of the slot from a circular hold open portion (not shown). The hold open has a slit at the end so that the hold open is able to expand to permit the slide pin to pass by the neck and into the hold open portion. The neck prevents the door from closing unless sufficient force is applied to push the pin back through the neck. 
     As shown in FIGS. 7A,  8  and  9 A, the lower hinge pin  43  is provided for during the frame molding process by forming the lower cylindrical opening  39  for the bushing  39   a , and after the molding process a plastic sleeve  39   b  is received in the metal bushing as a bearing for the lower hinge pin  43  which is free of any fixed connection to the molded frame F. The lower bushing  39   a  may be secured to a lower reinforcing member  43   a  (FIG. 7A) for reinforcing the frame F in the door mounting area where the major weight of the door D is translated to the casing C. The reinforcing member  43   a  is preferably molded into the frame F. The lower end  43   b  of the hinge pin projects outwardly below the frame F and is hexagonal (or otherwise shaped) to have a non-rotational fit into a complementary opening  43   c  in a casing bearing plate  43   d  bolted to the casing C. Thus, the door D will turn on the lower hinge pin  43  as it is opened and closed while the lower hinge pin is stationary relative to the cabinet casing C. 
     A torsion rod  45  is fixedly attached at its lower end to the lower hinge pin  43  whereby the lower end of the torsion rod is held from rotation relative to the lower hinge pin and casing C. The torsion rod  45  is an elongated spring steel member of square cross-section or the like (FIG. 10) which functions to bias the door D toward its closed position. To that end, the upper end  45   b  of the rod  45  is fixed for conjoint pivoting movement with the door. Referring now to FIGS. 8,  9 A and  10 , the upper end  45   b  of the torsion rod  45  is positioned in a torque adjustment housing  46  mounted in a recessed opening  46   a  formed in the hinge margin  35   a  of the molded frame F at a vertically central location of the door (FIG.  8 ). A cover plate  46   b  has two screws  46   c  to mount the cover plate over the housing  46  in the frame. The upper end of the torsion rod  45  has a spur gear  47  rotatably positioned in an arcuate housing section  47   a , and the teeth of the spur gear  47  entrain with the helical tooth of a worm gear  48  in the adjacent housing section  48   b . The worm gear  48  is turned by a recessed Allen head screw  48   c  to turn the spur gear  47  and upper end of torsion rod  45  to torque the rod about its longitudinal axis and either increase or decrease the amount of torsional deflection of the torsion rod. The more the torsion rod is twisted about its axis, the greater latent spring closing force the torsion rod  45  exerts on the door. The provision of the adjustment housing and worm gear in the door provides for easy access to adjust the closing force of the door as necessary. As will become more apparent in the description of the door molding process hereinafter, provision is made to accommodate the torsion rod  45  and the torque adjustment housing  46  by creating the lower cylindrical opening  39 , which extends vertically in the molded frame and into the housing opening  46   a . The torsion rod  45  is sheathed within a plastic or like sleeve member  45   c  of the same cross-section as the spur gear housing  47   a  and the lower end of which is nested within the sleeve  39   a.    
     In order to keep the door lites clear of exterior condensation and/or to clear interior condensation after the door has been opened, it is presently preferred that the inner surface  19   a  of the outer lite  19  (FIGS. 12,  13 ) is heated. Heating is accomplished by applying an electrical potential across a transparent, electrically conducting film on the inner surface  19   a . Electricity is brought into the door D through the electrical connector section  32  of the plug-in key located on the hinge margin  35   a  of the door frame F. The electrical connector section  32  has a main oval body  32   c  molded into the frame F and having a female socket  32   a  that receives a typical male connector plug (not shown) from the merchandiser casing C. Electrical contacts of the male connector mate with prongs  32   b  located in the socket recess so that the door is plugged into the merchandiser as a source of electrical power (FIGS. 8,  13 ). The prongs are made of a suitable electrically conducting material, such as bronze. As shown in FIGS. 5,  5 A,  6 ,  6 A,  9  and  11 , the electrical heating means for the door lite includes spring leaf contacts  50 , 50   a  which protrude from the inner locking body-side of the key  30  and extend in opposite directions. Preferably, these leaf contacts are made of a softer material, such as copper, and are connected to the respective prongs  32   b  through the inside of the key (FIG.  13 ). The leaf contacts may be made of the other electrically conductive materials and may be formed as one piece with the prongs. 
     The leaf contacts  50 , 50   a  are pressed against the outer sides  21   a  of the inner spacer body  21  of the spacer by the inner lite  17 , and against conductors  51 , 52  received in a recess or groove along the side  21   a  of the spacer body. The conductors are a copper foil in the preferred embodiment, but may be of another electrically conductive material. As shown in FIG. 11, a first of the conductors  51  extends from adjacent the electrical plug-in and spacer locking key  30  upwardly to the upper corner of the door frame, and a second of the conductors  52  extends from adjacent the electrical key downwardly to the lower corner of the door frame. The electrical conductors  51 , 52  are sandwiched between the electrically insulating inner surface  17   a  of the inner glass lite and the electrically insulating spacer. The molded frame F extends onto the inner lite  17  a distance greater than the depth of insertion of the spacer body  21  between the inner lite  17  and middle lite  18  so that the spacer is covered. Accordingly, the conductor is also covered by the molded frame which isolates it from sight and touch of the customer so that even if the outer lite should break, the conductor is still shielded between the frame and spacer from incidental contact. 
     At the upper and lower corners, respective crossover connectors  53  electrically connect the first conductor  51  to an upper bus bar  54  and the second conductor  52  to a lower bus bar  55  (FIG.  14 ), Referring to FIG. 12, the upper bus bar  54  extends between the spacer body  21  and the inner surface  19   a  of the outer lite  19  across the top of the door. Similarly, the lower bus bar  55  extends between the spacer body  21  and the inner surface  19   a  of the outer lite  19  across the bottom of the door. Each bus bar is a copper foil and is in contact with the conductive film on the inner surface of the outer lite so that the bus bars are able to apply an electrical potential between the top and bottom of the inner surface. The compressive force applied by the molded frame F, when formed, is sufficient to secure the electrical engagement of the bus bars  54 , 55  with the film on the outer lite  19 . It is noted that the bus bars are screened from view and protected from incidental contact in the event the outer lite breaks. 
     As shown in FIG. 14, the crossover connectors  53  include a crosspiece  53   a  and end tabs  53   b  which are oriented at right angles to the crosspiece. The end tab  53   b  on one side of the spacer contacts the second conductor  52  running down from the electrical plug-in  30  and connects across the IG unit to the other end tab engaging the lower bus bar  55  (FIG.  12 ). The crosspiece  53   a  extends through the slots  53   c  formed at the notches  25  of the spacers (FIG. 4) to transfer the electricity across the insulated space between the inner lite  17  to the lower bus bar  55  connected with the electrically conductive film on the inner surface  19   a  of the outer lite  19 . The crosspiece  53  at the top of the door similarly connects the conductor  51  on one side of the panel with the bus bar  54  on the outer lite. Thus, the crosspieces do not interfere with the right angle geometry and close fit of the spacers at the corners with the glass lites. 
     In another embodiment of the present invention, only the inner surface  17   a  of the inner lite  17  would be heated and thus the electrically conductive film would be applied to that surface ( 17   a ). In that event, the arrangement of the conductors  51 , 52  and bus bars  54 , 55  would be reversed from that described above and shown in the drawings (particularly FIGS.  11  and  12 ). The conductors  51 , 52  would be disposed between the outer lite  19  and the spacer body  21  adjacent the outer lite, and the bus bars  54 , 55  would be disposed between the inner surface  17   a  of the inner lite  17  and the spacer body adjacent thereto. In this embodiment, at least the middle lite  18  and possibly the outer lite would have a low emissivity material coating to further reduce heat transfer through the glass. In addition, the space between adjacent lites may be filled with a dry gas, such as Argon or Krypton, having low thermal conductivity. The increased thermal resistance of this arrangement reduces concern over condensation. Thus, the heated surface is shifted to the inside lite where it is still needed for door clearing. This embodiment is more energy efficient since only about half the power is required to clear the door in a commercially acceptable time. 
     Method for Making the Reach-In Door 
     The reach-in door of the present invention is assembled by first providing the various component parts, including the outer  19 , middle  18  and inner  17  glass lites, the spacer S, electrical plug and spacer locking key  30 , and torsion rod adjustment assembly ( 38   a , 38   b , 39   a , 45 , 45   c , 46 , 47 , 48 ) and reinforcing members  40   g , 43   a . The inner surface  19   a  of the outer lite  19  is formed with a transparent, electrically conductive film. The lites are washed immediately prior to assembly, and the edge surfaces of the inner and outer lites  17 , 19  (which will be contacted by the molded frame material) are primed with a chemical adhesion promoter to promote bonding of the molded frame material (e.g., polyurethane) to the glass. 
     In providing the component parts, the spacer S is extruded from a polymer or other suitable material having an appropriate Underwriter&#39;s Laboratories rating. The polymer material selected should have thermal and electrical insulating properties and produce minimal chemical fogging of the glass surfaces. The spacer strip S is angle cut with the notches  25  through the separator body portion  21  to define the body sections or segments that correspond to the respective lengths of the glass lite sides, with the free end segments  26   a  being over-length. The strip is also slotted, at  53   c , to later accommodate the cross-over connectors  53 , and the holes  24   b  are formed in the inner free side of the body segments. Also, at least one of the hollow body segments is filled, as needed, with desiccant  24   a , and the ends of such segments are plugged or taped to retain the desiccant. The copper foil bus bars  54 , 55  are adhered to the side of the spacer body segments  26   d , 26   b  which will ultimately extend across the top and bottom of the door in contact with conductive film on the inner surface  19   a  of the outer lite  19 . It is also permissible to adhere the bus bars  54 ,  55  directly to the glass, although assembly is believed to be simplified by providing them on the spacer. The copper foil conductors  51 , 52  are also affixed to the opposite side of the spacer body segments  26   a , 26   e  which will engage the inner surface  17   a  of the inner lite  17  along the hinged edge margin of the door D, when assembled. 
     In a three-lite panel, the spacer S is then folded or wrapped around the middle glass lite  18 , the marginal edge of which is received in the central groove between the opposed side walls  21   a  of the spacer bodies  21  and abutting against the connecting web  22   a  of the outer wall  22 . The spacer is constructed and arranged so that the corners of the glass correspond to the notches  25  in the spacer to permit the spacer to be bent 90° and fit together and mate in the manner of a mitered corner, so that they extend substantially uninterruptedly through the corners. The spacer is constructed and arranged such that it extends nearly the entire distance around the perimeter of the middle lite  18 . However, the free ends  25   a  of spacer sections  26   a , 26   e  will be spaced apart to permit the interlocking connection by the locking plugs  31   c  of the spacer locking key  31 . These plug-in tabs  31   c  are inserted into the hollow openings  24  at the opposing ends  25   a  of the spacer, and the detents  31   e  on the keys  31   c  snap into the openings  31   d  in the spacer for locking engagement. 
     The inner and outer lites  17 , 19  are then inserted into the initial unit formed by the spacer S and middle lite  18 . The inner and outer lites fit against respective spacer bodies  21  and the outer marginal edges  23  of these lites are received under the flanges  22   b  of the spacer. If the tape  33  is not pre-applied to the spacer wall  22 , then the moisture barrier tape  33  is now applied to the respective side stretches of the wall  22  and turned to extend over slightly (e.g., approximately 0.10 inches) onto the outer lite surfaces. The taping step is done to make certain that the spacers are sealed with the lites especially at the corners to prevent intrusion of molded frame material between the lites. Pre-application of moisture barrier tape can be eliminated in favor of a taping step after the spacer has been applied to capture the glass lites and form the basic IG unit. In that event, the taping would be extended over the entire length of the spacer, and especially at the corners. In addition, tape is placed around the electrical plug-in and spacer locking key  31 . A portion of the tape  33  has been broken away in FIGS. 5 and 5A and  12  to illustrate its presence. In addition, a strand or rope of sealant (e.g., polyisobutylene) may be wrapped around the socket  32   a  of the electrical key  32  to promote bonding and sealing between the electrical key portion  32  and the molded frame material. 
     The captured spacer and glass lites subassembly is placed into a mold (not shown) for forming the door frame. In addition, the reinforcing members  40   g , 43   a , including the hinge pin bushings  38   a , 39   a  are positioned in the mold, as is the torque adjustment housing  46 . The bushing  39   a  associated with the lower hinge pin  43  is accompanied by a sleeve  45   c  which houses the torsion rod  45  below the torque adjustment housing  46 . Suitable bushings (not shown) are placed in the mold for the door handle H, and other suitable fixtures or disposable members are provided to form other openings and spaces for reducing space or otherwise as needed. The mold is closed and the molded frame F is formed by introducing one or more shots of liquid polyurethane frame material or the like into the mold cavity. The desiccant in the spacer bodies  21  may in certain circumstances provide structural integrity for the spacer bodies of the spacer during molding. The construction and arrangement of parts within the mold is designed to prevent the incursion of door frame material to circumvent the spacer and enter the spaces between the lites  17 , 18 , 19 . Such an incursion would produce an aesthetically unacceptable product. The sealing lips  21   c  on the spacer bodies also provide protection against door frame material moving past the spacer, tending to block further movement of any material which manages to enter under the flange  22   b  between the lites and the spacer body. A period is allowed for demolding and the mold is opened. Known procedures may be used to provide protection for the molded frame against ultraviolet degradation. 
     The interior of the captured glass panel subassembly (i.e. the spaces between adjacent lites  17 , 18  and  19 ) is sealed by the bonding action of the molded frame F around and onto the inner and outer lites  17 , 19 . The “air” spaces between the panes of glass may be selectively filled with an a dry gas, such as Argon or Krypton having low thermal conductivity. The torsion rod  45  with spur gear  47  (and lower hinge pin  43 ) are slid into the sleeve member  45   c  and housing chamber  47   a  with the sleeve  39   b  being positioned inside the bushing  39   a . The torque adjustment worm gear  48  is mounted in the torque adjustment housing  46  and is meshed with the spur gear  47   b  on the upper end of the torsion rod, and the cover plate  46   b  is secured. The sleeve  38   b  is inserted in the upper bushing  38   a , and the spring  40   a  and upper hinge pin  40  are now received in the sleeve  38   b  and bushing  38   a  at the top of the door. The handle H is also attached to the door, the magnetic strip holder  20  (including the magnetic strip) is inserted into the groove  20   b  and other hardware applied. It is to be understood that fewer than all of the foregoing steps may occur at one manufacturing location. For instance, the spacer could readily be produced at a remote location and shipped to the final assembly site. 
     The present reach-in door D for a merchandiser M therefor has excellent thermal insulation and product display qualities, and achieves the other objects set out for the invention. Moreover, assembly of the door is carried out with a limited number of steps. It is to be understood that the foregoing description and accompanying drawing have been given only by way of illustration and example, and that changes and modifications in the present disclosure, which will be readily apparent to all skilled in the art, are contemplated as within the scope of the present invention, which is limited only by the scope of the appended claims.