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CROSS REFERENCE TO RELATED APPLICATION 
     This is a Continuation-In-Part application of application Ser. No. 14/300,743, filed Jun. 10, 2014 entitled METAL DOOR. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to a metal door and more particularly to a metal door including first and second side frames or stiles and upper and lower frames or rails. Even more particularly, the first and second side frames have identical structures and the upper and lower frames have identical structures. Each of the frames has a metal front panel and a metal back panel which is spaced rearwardly of the front panel. Spaced-apart insulating panel connectors are positioned between the front and rear panels and are secured thereto to secure the front and rear panels together. An insulating foam material is positioned between the panel connectors. 
     2. Description of the Related Art 
     Many types of metal doors have been previously provided. The metal doors of the prior art are very durable and are resistant to forced entry attempts by burglars or the like. A problem associated with the metal doors of the prior art is encountered when the metal doors are subjected to cold temperatures. In such a situation, the inside portion of the metal doors of the prior art may “frost-up” when the metal doors are subjected to very cold temperatures. 
     Applicant&#39;s earlier metal doors, such as described in U.S. Pat. Nos. 8,534,027 and 8,656,684, represent distinct improvements in the metal door art. However, since the exterior and interior panel members of the &#39;027 and &#39;684 patents were each constructed of tubular steel members, the doors thereof are quite heavy. The invention set forth in the co-pending application represents an improvement in the art. The instant invention represents a further improvement in the metal door art. 
     SUMMARY OF THE INVENTION 
     This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key aspects or essential aspects of the claimed subject matter. Moreover, this Summary is not intended for use as an aid in determining the scope of the claimed subject matter. 
     A metal door is disclosed which includes vertically disposed and vertically extending first and second side frames or stiles and horizontally disposed and horizontally extending upper and lower frames or rails. One end of the upper frame is secured to the upper end of the first side frame with the other end of the upper frame being secured to the upper end of the second side frame. One end of the lower frame is secured to the lower end of the first side frame and the other end of the lower frame is secured to the lower end of the second side frame. 
     The first side frame includes horizontally spaced-apart front and rear panels which are connected together by means of a pair of panel connectors positioned therebetween. The panel connectors are comprised of an insulating material such as wood, fiberglass or plastic. The space between the panel connectors in the first side frame is filled with an insulating foam material. The second side frame of the door is identical to the first side frame. The upper frame or rail includes spaced-apart front and rear panels which are connected together by a pair of insulating panel connectors. The space between the panel connectors in the upper frames is filled with an insulating foam material. The lower frame or rail is identical to the upper frame. 
     An optional intermediate frame may be extended between the first and second side frames above the lower end of the door if so desired. The intermediate frame will have the same construction as the upper and lower frames and may be straight or curved. 
     A door frame is also disclosed in which the door is positioned. The door frame also includes insulating material therein. 
     A principal object of the invention is to provide an improved metal door. 
     A further object of the invention is to provide an improved metal door which has improved insulation therein. 
     A further object of the invention is to provide an improved metal door wherein the door includes a first side frame, a second side frame, an upper frame and a lower frame wherein each of the frames include front and rear panels which are connected together by insulating panel connectors which have insulating foam material therebetween. 
     A further object of the invention is to provide an improved metal door which is economical of manufacture, durable in use and refined in appearance. 
     These and other objects will be apparent to those skilled in the art. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Non-limiting and non-exhaustive embodiments of the present invention are described with reference to the following figures, wherein like reference numerals refer to like parts throughout the various views unless otherwise specified. 
         FIG. 1  is an interior perspective view of a pair of metal doors of this invention; 
         FIG. 2  is an exploded sectional view of the leg or jamb of the door frame in which the door of this invention is mounted; 
         FIG. 3  is a sectional view of the leg or jamb of the door frame of  FIG. 2  after the leg or jamb is assembled; 
         FIG. 4  is an interior elevational perspective view of the door of this invention; 
         FIG. 5  is an exploded perspective view of the first side frame or stile of the door of this invention; 
         FIG. 6  is a partial sectional view of the first side frame or stile of this invention and the leg or jamb of the door frame; 
         FIG. 7  is a partial sectional view of the second side frame or stile of the door of this invention; 
         FIG. 8  is an exploded sectional view of the upper frame or rail of the door of this invention; 
         FIG. 9  is a sectional view of the upper frame of the door or rail of this invention in its assembled position; 
         FIG. 10  is an exploded sectional view of the lower frame or rail of the door of this invention; and 
         FIG. 11  is a sectional view of the lower frame or rail of the door of this invention in its assembled position. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Embodiments are described more fully below with reference to the accompanying figures, which form a part hereof and show, by way of illustration, specific exemplary embodiments. These embodiments are disclosed in sufficient detail to enable those skilled in the art to practice the invention. However, embodiments may be implemented in many different forms and should not be construed as being limited to the embodiments set forth herein. The following detailed description is, therefore, not to be taken in a limiting sense in that the scope of the present invention is defined only by the appended claims. 
     The metal door of this invention is designated by the reference numeral  10  and includes a vertically disposed first side frame or hinge stile  12 , a vertically disposed second side frame or lock stile  14 , a horizontally disposed upper frame or top rail  16 , a horizontally disposed lower frame or bottom rail  18 , and an optional intermediate frame or rail  20  which extends between side frames  12  and  14  between the upper frame  16  and the lower frame  18 . Frame  20  may be straight or curved. The door  10  shown herein will be inwardly hinged at the right side thereof as viewed from the interior thereof ( FIG. 1 ). The door could be inwardly hinged at the left side thereof if so desired, as shown in  FIG. 1 . The door  10  could be outwardly hinged if so desired. 
     Side frame or stile  12  will be described as having an upper end  22 , a lower end  24 , an inner end  26 , an outer end  28 , an exterior front side  30  and an interior rear side  32 . Side frame  12  includes a vertically disposed metal front or exterior panel  34  and a vertically disposed metal rear or interior panel  36  which is spaced rearwardly of front panel  34 . A flange  38  extends transversely rearwardly from the outer end of front panel  34 . A flange  40  extends inwardly from the rearward end of flange  38 . A flange  42  extends transversely rearwardly from the inner end of front panel  34 . A flange  44  extends outwardly from the rearward end of flange  42 . 
     A flange  46  extends transversely forwardly from the outer end of rear panel  56 . A flange  48  extends inwardly from the forward end of flange  46 . A flange  50  extends transversely forwardly from the inner end of rear panel  36 . A flange  52  extends outwardly from the forward end of flange  50 . 
     The numeral  54  refers to a vertically disposed and vertically extending panel connector which is comprised of wood, fiberglass, plastic or other insulative material and which has an upper end, a lower end, a front side  56 , a rear side  58 , an outer side  60  and an inner side  62 . A vertically disposed slot or groove  64  is formed in the outer side  60  of panel connector  54 . Panel connector  54  has a plurality of vertically spaced-apart bolt openings  66  formed therein. A plurality of vertically spaced-apart bolts  68  have the heads  70  thereof welded to front panel  34  and are received in the bolt openings  66 . Nuts  72  secure the panel connector  54  to front panel  34 . Panel connector  54  is positioned between front panel  34  and rear panel  36  at the outer end thereof inwardly of flanges  38  and  46  so that flange  40  of front panel  34  and flange  48  of rear panel  36  are received in slot  64 . Although it is preferred that panel connector  54  is secured to the panel  34  as described, the bolts  68  could be extended through the panel connector  54  so that the heads  70  thereof are received in the inner ends of the bolt openings  66  with the outer ends of the bolts  68  being welded to the panel  34 . In that method, there is no need for the nuts  72 . 
     The numeral  74  refers to a vertically disposed and vertically extending panel connector which is comprised of wood, fiberglass, plastic or other insulative material and which has an upper end, a lower end, a rear end  76 , a front end  78 , an outer side  80 , and an inner side  82 . A vertically disposed slot  84  is formed in the inner side of panel connector  74 . Panel connector  74  has a plurality of vertically spaced-apart bolt openings  86  formed therein. A plurality of vertically spaced-apart bolts  88  have the heads  90  thereof welded to rear panel  36  and are received in the bolt openings  86 . Nuts  91  secure the panel connector  74  to rear panel  36 . Although it is preferred that the panel connector  74  is secured to the panel  36  as described, the bolts  88  could be extended through the panel connector  74  so that the heads  90  thereof are received in the inner ends of the bolt openings  86  with the outer ends of bolts  88  being welded to the panel  36 . In that method, there is no need for the nuts  91 . The side frame  14  of door  10  is identical to side frame  12  and will not be described in detail for purposes of conciseness. In  FIG. 4 , the structure of the second side frame  14 , which is identical to the structure of the first side frame  12 , will be indicated with “′”. 
     Upper frame  16  has a first end  92  which is secured to the upper end  22  of side frame  12  and a second end  94  which is secured to the upper end  22 ′ of side frame  14 . Upper frame  16  includes a vertically disposed metal front panel  96  having an upper end  98  and a lower end  100 . A flange  102  extends transversely rearwardly from the upper end  98  of front panel  96 . A flange  104  extends downwardly from the rearward end of flange  102 . Flange  106  extends transversely rearwardly from the lower end  100  of front panel  96 . Flange  108  extends upwardly from the rearward end of flange  96 . 
     Upper frame  16  also includes a vertically disposed rear panel  110  having an upper end  112  and a lower end  114 . A flange  116  extends transversely forwardly from the upper end  112  of rear panel  110 . Flange  118  extends downwardly from the forward end of flange  116 . Flange  120  extends transversely forwardly from the lower end  114  of rear panel  110 . Flange  122  extends upwardly from the forward end of flange  120 . An elongated and horizontally disposed panel connector  124  is positioned between front panel  96  and rear panel  110  of upper frame  16  at the upper end of upper frame  16 . Panel connector  124  has a front side  126 , a rear side  128 , a lower end  130  and an upper end  132 . The upper end  132  of panel connector  124  has a slot  134  formed therein which receives flange  104  of front panel  96  and flange  118  of rear panel  120 . The slot  134  is filled with a caulking material. Panel connector  124  has a plurality of vertically spaced bolt openings  136  formed therein which receive bolt members  138  therein. The heads  140  of bolt members  138  are welded to rear panel  110 . Nuts  142  are secured to bolt members  138  to secure panel connector  124  to rear panel  110 . Panel connector  124  is comprised of wood, fiberglass, plastic or other insulative material. 
     Although it is preferred that the panel connector  124  is secured to the panel  110  as described, the bolts  138  could be extended through the panel connector  124  so that the heads  140  thereof are received in the inner ends of bolt openings  136  with the outer ends of the bolts  138  being welded to the panel  110 . 
     An elongated and horizontally disposed panel connector  146  is positioned between front panel  96  and rear panel  110  of upper frame  16  at the lower end of upper frame  16 . Panel connector  146  has a front side  148 , a rear side  150 , a lower end  152  and an upper end  154 . The lower end  152  of panel connector  146  has a slot or groove  156  formed therein which receives the flange  108  of front panel  96  and flange  122  of rear panel  120 . Slot  156  is filled with a caulking material. Panel connector  146  has a plurality of vertically spaced-apart bolt openings  158  formed therein which receive bolt members  160  therein. The heads  162  of bolt members  160  are welded to front panel  96  of upper frame  16 . Nuts  164  are secured to the bolt members  160  to secure panel connector  146  to front panel  96 . A foam insulation material  166  is positioned in upper frame  16  between the panel connectors  124  and  146 . Although it is preferred that the panel connector  146  is secured to the panel  96  as described, the bolts  160  could be extended through the panel connector  146  so that the heads  162  thereof are received in the inner ends of bolt openings  158  with the outer ends of the bolts  160  being welded to the panel  96 . 
     Lower frame  18  is secured to the lower ends of side frames  12  and  14  and extends therebetween. Lower frame  18  is identical to upper frame  16  and will not be described in detail. Identical structure of lower frame  18  to upper frame  16  will be designated with “′”. 
     The door  10  is mounted in a door frame generally indicated by the reference numeral  168 . Door frame  168  includes legs or jambs  170  and  172 , a sill or threshold  174  and a head  176 . Door frame  168  will obviously accommodate a single door  10  or a pair of doors such as seen in  FIG. 1 . 
     The legs or jambs  170  and  172  as well as the head  176  will normally be identical, so only jamb  170  will be described in detail. Jamb  170  includes a front metal unit  178  and a rear metal unit  180  which are secured to a panel connector  182  comprised of wood, fiberglass, plastic or other insulative material. Panel connector  182  has bores  184  and  186  extending therethrough. Panel connector  182  also has elongated slots  188  and  190  formed therein. The flanges  192  and  194  of front unit  170  are received in the slots  188  and  190 . The flanges  196  and  198  are also received in the slots  188  and  190  of panel connector  182  respectively. Screws  200  and  202  extend through openings formed in front unit  178  into the ends of bore  184  to secure front unit  178  to panel connector  182 . Screws  204  and  206  extend through openings formed in rear unit  180  into the ends of bore  186  of panel connector  182  to secure the rear unit  180  to panel connector  182 . A foam insulation material  208  is positioned in front unit  178 . 
     The door  10  will normally have a glass unit  210  mounted therein which is preferably hinged so as to be inwardly moveable, as seen in  FIG. 1 . Door  10  also will normally have a metal grill  212  mounted therein. 
     Thus, it can be seen that a metal door has been provided wherein the front and rear panels of the first side frame, the second side frame, the upper frame and the lower frame have a thermal break therebetween. It can therefore be seen that the invention accomplishes at least all of its stated objectives. 
     Although the invention has been described in language that is specific to certain structures and methodological steps, it is to be understood that the invention defined in the appended claims is not necessarily limited to the specific structures and/or steps described. Rather, the specific aspects and steps are described as forms of implementing the claimed invention. Since many embodiments of the invention can be practiced without departing from the spirit and scope of the invention, the invention resides in the claims hereinafter appended.

Summary:
A metal door comprising first and second side frames or stiles and upper and lower frames or rails which are joined together. Each of the frames includes front and rear panels which are spaced apart and which are secured together by means of insulating panel connectors. The space between the panel connectors in each of the frames is filled with an insulating foam material. The panel connectors are also comprised of an insulating material such as wood, fiberglass, plastic or other insulative material.