Abstract:
The present invention relates to a door frame, particularly a door frame for a pre-hung door assembly, which is foldable to minimize storage space and to allow for enhanced logistic efficiencies. The door frame contains parallel, spaced apart, vertical jambs and a horizontal header connecting the top ends of the jambs. Each of the jambs and the horizontal header contains a front section and back section that are hingedly joined so that then can be folded on to each other. The hingedly joined front and back sections allow the door fame to be foldable to minimize space occupied during storage.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS AND CLAIM TO PRIORITY 
       [0001]    This application claims priority to U.S. Provisional Patent Applications Nos. 62/307,148, filed Mar. 11, 2016, and 62/417,029, filed Nov. 3, 2016, the disclosures of which are incorporated herein by reference. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention relates to a door frame, particularly a door frame for a pre-hung door assembly, which is foldable to minimize storage space during shipping and to allow for enhanced logistic efficiencies. 
       BACKGROUND 
       [0003]    Many doors, either commercial or residential, are purchased as pre-hung door assemblies. A pre-hung door assembly is delivered for installation with the door already hingedly connected to the door frame that is to be inserted into the building opening where the door is to be located. Pre-hanging is accomplished by attaching the door to one side of the door frame, typically by one or more hinges. The other side of the door may be provided with a lockset and knob opening. The jamb member positioned immediately adjacent to the lockset and knob opening side is fitted with a latch or striker plate and associated opening so that the door can be securely shut after it has been installed. Pre-hanging is usually performed at the door-making facility, which typically is remote from where the door and its frame are to be installed. Once the door has been pre-hung it needs to be shipped, typically by truck, to the building location. 
         [0004]    Doors, especially pre-hung door assemblies, are usually stored by placing one directly adjacent to another front-to-back. This method of storage maximizes space usage by eliminating spaces between adjacent door assemblies. It is, therefore, desirable to have a door frame with a small foot print so that wasted space is further eliminated for efficient storage and enhanced logistic efficiencies. In other words, more doors and their frames can be shipped by truck if the foot print is reduced. Shipping can be expensive and thus costly, so minimizing that expense is important to reducing costs. 
       SUMMARY OF THE INVENTION 
       [0005]    An object of the present invention is to provide a door frame, particularly a door frame of a pre-hung door assembly. The door fame is configured to be foldable to minimize space occupied during storage and shipment. The door frame contains parallel, spaced apart, vertical jambs and a horizontal header connecting the top ends of the jambs. Each of the jambs and the horizontal header contains a front section and back section that are hingedly joined so that the front section can be folded onto the back section or vice versa. In the folded position, the door frame has a reduced foot print and takes up less space than in the unfolded or installation orientation. 
         [0006]    Another object of the present invention is to provide a pre-hung door assembly. The assembly includes a foldable door frame with a door slab hingedly hung on one of the door jambs. The door jambs and/or horizontal header may contain a door stop on their inner surface to function as a stop preventing the door slab from swinging through the opening of the frame. 
         [0007]    Further objects of the present invention include methods for making the door frame and pre-hung door assembly, and methods for installing the pre-hung door assembly. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]    The accompanying drawings are incorporated in and constitute a part of the specification. The drawings, together with the general description given above and the detailed description of the exemplary embodiments and methods given below, serve to explain the principles of the invention. In such drawings: 
           [0009]      FIG. 1  is a perspective view of a door frame in an opened or installation orientation; 
           [0010]      FIG. 2  is a perspective view of a door frame in a folded orientation; 
           [0011]      FIG. 3  is a cross-sectional view of an exemplary embodiment of a hinge side door jamb; 
           [0012]      FIG. 4  is a fragmentary cross-sectional view of a hinge side door jamb placed in an opening that is thicker than the jamb; 
           [0013]      FIG. 5  is a fragmentary cross-sectional assembly drawing of a hinge side door jamb and its substitute back section; and 
           [0014]      FIG. 6  is a perspective view of a living hinge. 
       
    
    
     DETAILED DESCRIPTION 
       [0015]    Reference will now be made in detail to exemplary embodiments and methods of the invention. It should be noted, however, that the invention in its broader aspects is not necessarily limited to the specific details, representative materials and methods, and illustrative examples shown and described in connection with the exemplary embodiments and methods. Like reference characters refer to like parts throughout the drawings. 
         [0016]    Referring to  FIG. 1 , the present invention provides a pre-hung door assembly  100  and methods for mounting the pre-hung door assembly  100  in a wall opening of a building. The door opening is typically framed by building studs connected by an opening header at the top of the studs. The door opening is prepared for a selected door frame size, so that a door frame  110  of selected size can fit and be retained therein. 
         [0017]    The pre-hung door assembly  100  typically contains the door frame  110  and a door slab  128  hung therein. The door frame  110  is typically formed by parallel, spaced apart, vertical jambs  120  (hinge side jamb),  122  (lock side jamb) and a horizontal header  124  connecting the top ends of the jambs  120 ,  122 , typically with mechanical fasteners. The jambs  120 ,  122  and horizontal header  124  are typically made of wood, such as pine, fir, with pine being preferred, although hardwoods may also be used; plastics; or composite materials. Preferably, the door jambs  120 ,  122  are constructed as flat jambs rather than split jambs. Optionally, the door frame  110  may also include a sill installed at the foot of the frame  110  and connecting the lower ends of the jambs  120 ,  122 . 
         [0018]    A door slab  128  is provided with the door frame  110 , as shown in  FIG. 1 , to form the pre-hung door assembly  100 . The doors slab  128  may be solid core or hollow core and constructed, e.g., as described in U.S. Patent Application Publication No. 2014/0261991, the disclosure of which is incorporated herein by reference. The door slab  128  may be hingedly attached to the hinge side jamb  120  by two or more door hinges. Two, three, four, five, or more door hinges may be used to attach the door slab  128  to the hinge side jamb  120 , depending on the size of the door. For a typical door used in a home, three hinges are typically used to mount the door slab  128  to the door frame  110 . The door hinges may be typical hinges, such as made from steel, used to mount doors to allow the door slab  128  to swing between a closed position and an opened position within the door frame  110 . As used herein and shown in  FIG. 1  via the arrow, the side toward which the door slab  128  opens is referred to as the back side, while the opposing side is referred to as the front side. Preferably, the door jambs  120 ,  122  and/or horizontal header  124 , each contains a door stop (best shown as  300  in  FIG. 3 ) on its inner surface. The door stop  300  functions as a stop for the door slab  128 , not allowing it to swing through the opening without damage to the hinges. 
         [0019]      FIG. 1  shows the frame  110  in an unfolded or installation orientation, where each member of the frame (the jambs  120 ,  122  and the horizontal header  124 ) contains a front section and back section. The hinge side jamb  120  contains a front section  120   a  and a back section  120   b;  the lock side jamb  122  contains a front section  122   a  and a back section  122   b;  and the horizontal header  124  contains a front section  124   a  and a back section  124   b.  Each of the front sections  120   a,    122   a,  and  124   a  are joined by one or more hinges  130  to its respective back section  120   b,    122   b,    124   b.  The hinge  130  may be a living hinge (a thin flexible section connecting the front section  120   a,    122   a,  or  124   a  to its corresponding back section  120   b,    122   b,  or  124   b ) when the frame  110  is made of resilient plastic, such as polypropylene ethylene (PPE), high density polyethylene (HDPE), polyethylene, nylon, polyvinyl chloride (PVC), or combinations thereof, or a resilient composite material, such as wood composite (e.g. particle board or fiberboard), polymer based composites (e.g. fiberglass/polyester resin or wood fiber/polyethylene), or combinations thereof, or may be a flexible material, such as a strap or a tape (as best shown in  FIG. 1 ). The living hinge may be formed separately from the resilient plastic material and attached to the front and back sections, e.g. by adhesive. Such a separate living hinge, as illustrated in  FIG. 6 , contains a thin section  600  between two thicker sections  602 ,  604 . The thick sections  602 ,  604  are attached to the front section  120   a,    122   a,  or  124   a  and its corresponding back section  120   b,    122   b,  or  124   b.  The thin section  600  allows the front section  120   a,    122   a,  or  124   a  and back sections  120   b,    122   b,  or  124   b  to be folded on each other. Alternatively, the hinges  130  may be conventional mechanical hinges, such as bi-fold metal hinges. When in an opened position ready for installation, as shown in  FIG. 1 , the front and back sections of each member of the frame  110  lay edge-to-edge with the back edge of the front section abutting the front edge of the back section, such that the hinges  130  lay flat on the outside of the frame  110 . When a door slab  128  is present, it is preferably hingedly attached to the back section  120   b  of the hinge side door jamb  120 . The hinge  130  may extend the complete span of the jamb  120 ,  122  and horizontal header  124 , or may be applied in selected portions of the jamb  120 ,  122  and horizontal header  124 . 
         [0020]    For storage and shipping, the door frame  110  may be folded by laying the front sections  120   a,    122   a,    124   a  and back sections  120   b,    122   b,    124   b  of the door frame  110  one on top of the other, as best shown in  FIG. 2 . In an embodiment, the front sections  120   a,    122   a,    124   a  are folded back on the hinges  130 , so that they lay on their corresponding back sections  120   b,    122   b ,  124   b.  The front section  124   a  of the horizontal header  124  lays on the outside face of the back section  124   b;  the front section  120   a  of the lock side jamb  120  lays on the outside face of the back section  120   b;  and the front section  122   a  of the hinge side jamb  122  lays on the outside face of the back section  122   b.  When folded as illustrated in  FIG. 2  (folded position), the door frame  110  has a reduced foot print and takes up less room front-to-back for convenient storage. 
         [0021]    When ready for installation, the frame  110  is placed in the opened orientation, as best shown in  FIG. 1 , by folding the front sections  120   a,    122   a,    124   a  forwardly (toward the front of the door frame  110 ) and away from their corresponding back sections  120   b,    122   b,    124   b.  The front sections  120   a,    122   a  of the door jambs  120 ,  122  may then be secured to either ends of the front section  124   a  of the horizontal header  124  by mechanical fasteners, such as screws, nails, brackets, or combinations thereof. Alternatively, the front sections  120   a,    122   a,    124   a  may be secured directly to the wall opening without being secured to each other. 
         [0022]    In certain embodiments, the front sections  120   a,    122   a,    124   a  may be secured to their corresponding back sections  120   b,    122   b,    124   b  via an interlock mechanism, where each front section  120   a,    122   a,  or  124   a  contains a protrusion that snaps into and locks with a complementary channel in its respective back section  120   b,    122   b,  or  124   b.  Of course, the reverse may also be effected, where the back section  120   b,    122   b,  or  124   b  contains the protrusion, and the front section  120   a,    122   a,  or  124   a  contains the channel. An exemplary embodiment is shown in  FIG. 3 , where the front section  120   a  contains a protrusion  302 , and the back section  120   b  contains a channel  304  formed between the jamb  120   a  and its associated door stop  300 . The door stop  300  is preferably mounted to the back sections  120   b,    122   b,    124   b.  When the door jamb  120  is place in its opened orientation, the protrusion  302  fits into the channel  304  to interlock together the front and back sections  120   a,    120   b,  respectively. As illustrated in  FIG. 3 , the protrusion  302  may contain a beveled edge  310  to allow the back section  120   b  to slide easily into the channel  304 . 
         [0023]    In certain embodiments, the jamb  120  may also be held in its opened position by a tongue  306  on the door stop  300  that is lodged in a groove  308  in the back section  120   b . Preferably, the tongue  306  and the groove  308  are configured so that the tongue  306  fits snugly into the groove  308  to hold the jamb  120  in its opened position without significant play. Likewise, it is preferred that the protrusion  302  and the channel  304  fit together snugly to hold the back section  120   b  and the front section  120   a  tightly together. In other embodiments, however, the tongue  306  and groove  308  may be eliminated (as best shown in  FIG. 4 ). Although  FIG. 3  shows the interlock mechanism for the hinge side jamb  120 , the same may be effected for the lock side jamb  122  and the horizontal header  124 . Other interlocking mechanisms also be apparent to those skilled in the art. 
         [0024]    In certain embodiments, the door frame may  110  may be installed in a wall opening that has a thickness which does not match that of the door frame  110 . The thickness of the opening may be greater or less than the thickness of the door frame  110  (in its opened orientation). For example, as illustrated in  FIG. 4 , the thickness T of the opening may be greater than the thickness t of the door frame  110  in its opened orientation. In that case, a kit may be provided to replace the front sections  120   a,    122   a,    124   a  of the frame  110  with longer front sections  120   c,    122   c,    124   c  to match the thickness T of the opening. As best shown in  FIG. 5 , to match the thickness T of the opening, the front section  120   a,  having depth L b , of the hinge side jamb  120 , may be replaced with a substitute front section  120   c,  having depth L c , wherein L c  is greater than L b . Of course, the front sections  122   a  and  124   a  may also be replaced with corresponding substitute front sections  122   c  and  124   c.  Thus, the kit contains three substitute front sections: a first substitute front section  120   c  for the hinge side jamb  120 , a second substitute front section  122   c  for the lock side jamb  122 , and a third substitute front section  124   c  for the horizontal header  124 . The substitute front sections  120   c,    122   c,    124   c  replace the front section  120   a,    122   a,  and  124   a,  respectively. Although,  FIG. 5  shows the substitute front section  120   c  having a depth greater than L b , the present invention also contemplates the reverse case (L c  less than L b ), where the original frame  110  (in its opened orientation) has a thickness t greater than the thickness T of the wall opening. Preferably, the substitute front sections  120   c ,  122   c,    124   c  contain the same interlock mechanism described above for the front sections  120   a ,  122   a,  and  124   a,  including protrusions  302  and grooves  308  to allow the substitute front sections  120   c,    122   c,    124   c  to interlock with their respective back sections  120   b,    122   b,    124   b  and door stop  300  (see  FIG. 3 ). 
         [0025]    During installation, if the thickness T of the building opening does not match the thickness t of the door frame  110 , the installer may obtain a kit having substitute front sections  120   c,    122   c,    124   c  to match the thickness t of the frame with the thickness T of the opening. The installer may remove the front sections  120   a,    122   a,    124   a  from the frame  110 , e.g. by cutting or removing hinges  130 . The substitute front sections  120   c,    122   c,    124   c  are then used to replace front sections  120   a,    122   a,    124   a  to increase (or decrease) the thickness of the frame  110 . The installer may slide the substitute front sections  120   c,    122   c,    124   c  in place adjacent to their respective back sections  120   b,    122   b,    124   b  and door stop  300 , secure the substitute front jamb sections  120   c,    122   c  to the substitute front header section  124   c  (e.g. by fasteners, such as screws, nails, brackets, or combinations thereof), and optionally reinstall hinges  130  to secure the substitute front sections  120   c,    122   c,    124   c  to their respective back sections  120   b,    122   b,    124   b . Alternatively, a tape may be used to secure the substitute front sections  120   c,    122   c,    124   c  to their respective back sections  120   b,    122   b,    124   b.    
         [0026]    Although certain presently preferred embodiments of the invention have been specifically described herein, it will be apparent to those skilled in the art to which the invention pertains that variations and modifications of the various embodiments shown and described herein may be made without departing from the spirit and scope of the invention. Accordingly, it is intended that the invention be limited only to the extent required by the appended claims and the applicable rules of law.