Abstract:
An adjustable sill assembly includes an elongated substrate base composed of a molded composite material and defining a T-shaped slot extending along the length of the substrate base and open to a top surface of the substrate base; a sill plate connected with the substrate base; a riser having a top and two downwardly-extending legs defining an interior of the riser, the interior of the riser having a pair of flanges angling downward and toward one another; and means for connecting the substrate base with the riser including a T-nut having a flange and a corresponding screw, the T-nut being slidebly and non-rotatably supported within the T-shaped slot and the screw being rotatably and slideably supported by the pair of flanges and wherein the riser is secured to the substrate base by inserting the screw into the T-nut.

Description:
TECHNICAL FIELD OF THE INVENTION  
         [0001]    The present invention relates generally to door frames and, more particularly, to a modular sill assembly which may be vertically adjusted and adapted for a variety of doorway configurations.  
         BACKGROUND OF THE INVENTION  
         [0002]    In a standard threshold assembly, a sloping sill is attached to a base. The sill is oriented on the exterior of the door frame. A trim piece or nosing is generally attached to the opposite side of the base facing the interior of the door frame. Between the sill and trim piece, a riser or threshold cap is attached to the top of the base. The riser is positioned to underlie the door when it is in a closed position and form a seal with the bottom of the door.  
           [0003]    Several methods of attaching the riser to the base exist in the prior art. In particular, a number of these prior art designs provide for adjustment in the height of the riser relative to the base. These prior art designs tend to incorporate mechanisms, for example, corresponding nut and screw assemblies, that are fixed in position relative to the length of the base.  
           [0004]    The manufacture of the individual pieces comprising a sill assembly and the method of attaching the riser to the base have presented numerous design issues to the millwork industry. One particularly troublesome issue is the fact that, doorways, come in a large variety of configurations. For instance, a door frame may accommodate a door and a non-moving sidelight or a pair of opposing (“french”) doors and an astragal which may or may not be attached to one of the opposing doors. Current sill designs can be used in a limited number of configurations and provide little flexibility in the available configurations. While manufacturers have attempted to design threshold assemblies that are adaptive in some aspects, none have produced a design that provides sufficient adaptability. As mentioned above, the prior art designs generally utilize attachment mechanisms that are fixed in position relative to the length of the base.  
           [0005]    Furthermore, these prior art designs utilize a large amount of custom hardware, particularly in their attachment mechanisms, such as specialized shoulder screws and push nuts. This custom hardware increases the cost of the sill assembly and requires that manufacturers stock a large amount of custom pieces for which they have no other use.  
           [0006]    An improved sill assembly would preferably have a modular design that is capable of ready adaptation to various doorway configurations, while requiring a minimal amount of custom hardware for assembly.  
           [0007]    The present invention is directed to overcoming one or more of the problems set forth above.  
         SUMMARY OF THE INVENTION  
         [0008]    An aspect of the present invention is to provide a modular sill assembly that is easily adapted to a variety of different doorway configurations.  
           [0009]    Another aspect of the present invention is to provide a modular sill assembly that utilizes a means of connecting a riser to a substrate that is easily adaptable to whatever length and arrangement is required by a particular doorway design.  
           [0010]    Yet another aspect of the present invention is to provide a modular sill assembly that utilizes a minimal number of custom parts for assembly, thereby enhancing interchangability of parts in the system.  
           [0011]    In accordance with the above aspects of the invention, there is provided an adjustable threshold assembly that includes an elongated substrate base composed of a molded composite material and defining a T-shaped slot extending along the length of the substrate base and open to a top surface of the substrate base; a sill plate connected with the substrate base; a riser having a top and two downwardly-extending legs defining an interior of the riser, said interior of the riser having a pair of flanges angling downward and toward one another; and means for connecting the substrate base with the riser including a T-nut having a flange and a corresponding screw, said T-nut slideably and non-rotatably supported within the T-shaped slot and said screw rotatably and slideably supported by the pair of flanges and wherein the riser is secured to the substrate base by inserting the screw into the T-nut.  
           [0012]    These aspects are merely illustrative of the innumerable aspects associated with the present invention and should not be deemed as limiting in any manner. These and other aspects, features and advantages of the present invention will become apparent from the following detailed description when taken in conjunction with the referenced drawings. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0013]    Reference is now made to the drawings which illustrate the best known mode of carrying out the invention and wherein the same reference numerals indicate the same or similar parts throughout the several views.  
         [0014]    [0014]FIG. 1 is a perspective view of a doorway incorporating a sill assembly according to an embodiment of the present invention.  
         [0015]    [0015]FIG. 2 is a cross-sectional view of the sill assembly of FIG. 1 taken along line Z-Z.  
         [0016]    [0016]FIG. 3 is a partial section perspective view of an embodiment of a sill assembly illustrating a T-nut/screw fastening assembly.  
         [0017]    [0017]FIG. 4 is a cutaway view of an embodiment of a sill assembly  
         [0018]    [0018]FIG. 5 is a perspective view of an embodiment of a sill assembly for a doorway including an active door and sidelight or non-active door.  
     
    
     DETAILED DESCRIPTION  
       [0019]    [0019]FIGS. 1-4 illustrates a sill assembly shown generally at  10  including a substrate  12 , a sill  14 , a riser  16 , and a trim piece  18 . FIG. 1 illustrates a sill assembly  10  of this design installed in a door frame  20  between the door jambs.  
         [0020]    The substrate  12  shown in FIGS. 1-4 is generally rectangular in shape with a number of grooves formed therein. In the embodiment shown, the top surface  26  of the substrate  12  includes a first sill groove  28 . The bottom surface  30  of the substrate  12  includes a second sill groove  32 . The first and second sill grooves  28 ,  32  aid in securing the sill  14  to the substrate  12 . The substrate  12  is also provided with a first trim groove  34  in the top surface  26  and a second trim groove  36  in the bottom surface  30 . These grooves aid in securing the trim piece  18  to the substrate  12 . The top surface  26  of the substrate  12  also includes a T-shaped slot  38  that extends along the entire length of the substrate  12  and opens to the top surface  26 . In a preferred embodiment, the substrate  12  is manufactured from a composite material that is processed to form the desired cross-section for the substrate.  
         [0021]    The riser  16  includes a top surface  40  and first  42  and second  44  legs extending generally downward from the top surface. The top surface  40 , first leg  42  and second leg  44  define an interior  46  of the riser  16 . A first flange  48  and a second flange  50  are located within the interior  46  of the riser  16 . In the embodiment shown, the first flange  48  emanates from the first leg  42  and the second flange  50  is supported by the top surface  40  of the riser. However, the flanges  48 ,  50  may be supported by the first and second legs, respectively, the top surface  40 , or the top surface  40  and second leg  44 , respectively. Advantageously, the first and second flanges  48 ,  50  angle downward and toward one another forming a generally V-shaped structure with an opening  60  at the vertex of the flanges. An extension  52 ,  54  is located at the end of each flange  48 ,  50 . Preferably, the extensions  52 ,  54  are made of a softer durometer material than the rest of the riser  16 , such as a plastic material. The riser  16  itself is preferably made of an extruded plastic material, although a number of extrudable materials are suitable. In a preferred embodiment, the extensions  52 ,  54  are co-extruded with the rest of the riser. The riser  16  also includes a sealing leg  56  extending out and downward from the top surface  40  of the riser  16 . The sealing leg includes a sealing extension  58  that extends into the space between the sealing leg  56  and first leg  42 . The sealing leg  56  and extension  58  engage the sill in manner described below in order to form a weather seal for the sill assembly.  
         [0022]    During installation, the riser  16  is positioned on top of the substrate  12  with the opening  60  at the vertex of the flanges located generally above the T-shaped slot  38 . A T-nut  62  having a flange  64  is inserted into the T-shaped slot  38  with first and second lateral extensions  66 ,  68  of the slot accommodating the flange  64 . A corresponding screw  70  is inserted between the flanges  48 ,  50 , with the flanges supporting the head of the screw  70  and the threaded portion of the screw extending through the opening  60  between the flanges. The extensions  52 ,  54  of the flanges engage the screw  70  to restrict both vertical and lateral movement of the screw, thereby eliminating any need for a push nut or similar structure to secure the screw. This, in turn, eliminates the need to use special fasteners, for example, screws having shoulders designed to accommodate push nuts. Any standard screw of suitable length may be used instead. In order to secure the riser  16  to the substrate  12 , the screw  70  is inserted into the T-nut  62 , and the screw  70  is tightened. The height of the riser  16  relative to the substrate  12  is adjustable by varying the extent to which the screw  70  is tightened into the T-nut  62 . The riser  16  is preferably provided with a number of access holes  72  in the top surface  40  through which a screwdriver may be inserted in order to tighten the screw  70 . Caps  73  are provided to cover the access holes  72  and present a finished appearance. At least two T-nuts with corresponding screws are generally necessary to securely fasten the riser to the substrate in a level manner. In a preferred embodiment, a T-nut with a corresponding screw is positioned approximately every ten inches along the sill assembly.  
         [0023]    The slot  38  allows the T-nut  62  to be positioned anywhere along the length of the substrate  12 . Similarly, the flanges  48 ,  50  permit lateral movement of the screw  70  along the length of the riser  16 , although such movement does require some force due to the restriction of the extensions  52 ,  54 , to allow the screw  70  to be positioned anywhere along the length of the riser. This feature allows the position of the T-nut and screw fastening assemblies to be varied along the length of the riser/substrate subassembly. This arrangement enhances the modularity of the sill assembly by permitting greater interchangeability of parts.  
         [0024]    The sill  14  features a sloping top surface  74  having a number of ridges designed to enhance traction. On the underside of the sill  14  are located a front support  76  and a rear support  78 . Each of the supports  76 ,  78  is provided with a lateral extension  80 ,  82 . The front extension  80  is arranged to engage the second sill groove  32  in the substrate, while the rear extension  82  engages the first sill groove  28  to connect the sill  14  with the substrate  12 . The sill  14  also includes a sealing lip  84  which engages with the sealing leg  56  and extension  58  to form a weather seal. The remaining features of the sill  14  are generally known in the art and, therefore, will not be described in more detail.  
         [0025]    The trim piece  18  is preferably made from a material similar to that used for the riser  16 . Furthermore, both the riser  16  and trim piece  18  are provided with an identical finish in order to provide the sill assembly with aesthetically pleasing visible surfaces. The trim piece includes first and second connecting extensions  86 ,  88  which engage with the first and second trim grooves  34 ,  36  in the substrate, respectively, to secure the trim piece to the substrate.  
         [0026]    It is envisioned that each of the primary pieces of the sill assembly, the substrate, riser, sill and trim piece, will form a modular system in which these pieces may be interchanged. The easy adaptability of the system will decrease manufacturing costs and the amount of inventory a manufacturer must carry. Furthermore, because the screws used in the assemblies are standard, the amount of custom hardware necessary to assemble the product is minimized.  
         [0027]    [0027]FIG. 5 illustrates an embodiment of the sill assembly in a doorway having a door and a sidelight. The sill assembly  10  lies in a door frame (not shown in detail). A mullion  90  is positioned in the door frame between a door (not shown) and a sidelight  94 . A riser  16  attached to a substrate (not shown), as described above, extends under the door between one outer jamb and the mullion  90 . Between the mullion  90  and the other outer jamb, a sidelight adapter  96 , or fixed sill, is attached to the substrate to provide a level surface for installing the sidelight  94 . Like the other pieces of the system, the sidelight adapter  96  is intended to be extruded in a few standard lengths and cut to length at the installation site. A mullion adapter  98  is attached to the substrate between the riser  16  and the sidelight adapter  96  and provides a level surface for mounting the mullion  90 . This eliminates the need to cut the profile of the sill assembly into the mullion  90 .  
         [0028]    The above components are also suitable for use in patio or french doors. These doorways usually include dual opposing doors separated by an astragal. One of the opposing doors is generally kept fixed most of the time and is referred to as the non-active door. The astragal may be attached to one of the opposing doors but is usually attached to the non-active door. In this arrangement, a fixed sill can be attached to the substrate underneath the non-active door and the astragal, while a riser  16  can be positioned underneath the operating door. The modular design of the sill assembly allows the riser  16  and fixed sill to be easily configured whether the non-active door is on the right or left side of the doorway.  
         [0029]    Other objects, features and advantages of the present invention will be apparent to those skilled in the art. While preferred embodiments of the present invention have been illustrated and described, this has been by way of illustration and the invention should not be limited except as required by the scope of the appended claims and their equivalents.