Patent Publication Number: US-11047165-B1

Title: Durable entryway threshold

Description:
RELATED APPLICATIONS 
     This application claims priority to U.S. Provisional Application No. 62/824,025 filed on Mar. 26, 2019 and U.S. Provisional Application No. 62/908,771 filed on Oct. 1, 2019 both of which are incorporated herein by reference in their entirety. 
    
    
     TECHNICAL FIELD AND BACKGROUND 
     The present invention relates generally to entryway systems, and more particularly, to entryway threshold assemblies. 
     Conventional threshold assemblies are made of wood or metallic materials that are susceptible to damage from mechanical stress and ultraviolet light that degrades the overall appearance of the threshold and that may result in the removal of any paint or decorative coatings applied to the threshold exterior. Threshold assemblies are commonly damaged, for example, during construction as a result of heavy foot traffic and the transport of construction materials and waste into and out of a structure. Existing threshold also tend to be thermally conductive and, therefore, not energy efficient. 
     In addition to being durable, entryway threshold assemblies should be constructed to fit doors of varying heights and entryways of varying widths or lengths. With regard to spacing between the threshold and the bottom of a door, by maintaining a predetermined clearance between the threshold and the door, a door seal can effectively keep out unwanted intrusion of wind, moisture, pests, light, or thermal energy. It would further be advantageous to provide threshold assemblies constructed in a modular fashion that can be configured to fit entryways having varying door frame widths or entryway applications where it is desired to extend the length of the threshold outward from the entryway opening. 
     What is needed is a durable, aesthetically pleasing entryway threshold that is not only easy to install but also convenient to repair or replace when damaged. Preferably, the threshold assembly should also be adjustable to fit doors of varying heights and entryways of varying widths and lengths while providing a good thermal barrier to enhance energy efficiency in the associated building structure and to prevent condensation or icing that can reduce friction and lead to hazardous, slippery surfaces on or around an entryway. 
     It is, therefore, an object of the present invention to provide a threshold assembly that is durable and resistant to damage from mechanical stress and ultraviolet light exposure, adjustable to fit varying door heights and entryways of varying widths and lengths, thermally insulating, aesthetically pleasing, and convenient to repair all while providing the ability to manufacture the threshold in a cost effective manner. 
     SUMMARY 
     One embodiment of the threshold assembly includes a base portion having a rear nose wall, a vertically aligned attachment groove, a base channel extending between the rear nose wall and the attachment groove, and a top portion extending from a base portion front face to the attachment groove. The base channel accommodates a cap that optionally includes an adjustment screw that raises or lowers the cap or an associated screw cap cover to meet the bottom surface of doors of varying heights. The base top portion can be a graded surface with the height proximal to the attachment groove being a greater than the height near the front face to promote moisture runoff. The threshold assembly also includes a deck cover with a front surface, a rear face, a deck cover top surface extending between the front deck cover surface and the rear face, and a lower attachment wall extending downward from the deck cover top surface and configured to sit within the attachment groove to releasably secure the deck cover to the base portion. The assembly also includes a cap sized to sit within the base channel. 
     The base portion can also include a base channel wall that defines one sidewall of the attachment groove and an attachment groove shoulder that frictionally engages a lower attachment wall tab on the deck cover to further secure the deck cover to the base portion and help prevent moisture intrusion. The deck cover can also be secured to the base using a rabbeted front edge on the front face of the base that couples to a flange on the front deck cover surface. 
     The cap can also include additional features, such as a cap body having a cap interior cavity, a cap barrier portion extending from the front of cap body to define a cap recess that accommodates a vertically aligned dam portion of the deck cover, and cap legs that extend downward from the cap body and securely fit within the base channel. The cap can be made adjustable through a cap adjustment screw that extends through a passage in the cap body such that turning the screw raises or lowers the cap to meet doors of varying heights. The cap barrier portion optionally utilizes a cap gasket disposed on a distal end of the cap barrier opposite the cap body. The cap gasket frictionally engages the vertical dam portion and serves to further seal the cap recess and prevent moisture intrusion into the interior components of the threshold assembly and entryway. 
     Sizing notches can be formed in the base portion to make it easier to cut the threshold assembly to a given width to accommodate entryways of different widths. The base portion in some embodiments utilizes voids to save weight, transverse support ribs to add rigidity, or fastener blocks that accommodate fasteners driven into the base to secure the threshold assembly in place within an entryway. To extend the length of a threshold assembly, the deck cover can incorporate a deck cover nose extending from the front face that defines a nose cavity sized to couple to a projection on a threshold extender component. 
     In some embodiments, the deck cover or other components are made from a material that includes a coextruded first thermoplastic material and a coextruded polyvinyl chloride material. The first thermoplastic material can be an acrylic material, such as polymethyl methacrylate. The deck cover material can incorporate impact modifiers, such as nylon fibers or acrylate modifiers, among others, as well as other additives, such as ultraviolet light inhibiters and pigments. To reduce cost, the base portion or other components can be made from an injection-molded polyvinyl chloride composite material. The base portion can also be bonded to the deck cover, cap, and/or a nose cover made from separate coextruded thermoplastic materials. 
    
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
       Features, aspects, and advantages of the present invention are better understood when the following detailed description of the invention is read with reference to the accompanying figures, in which: 
         FIG. 1  is a cutaway, side view of a threshold assembly according to one embodiment. 
         FIG. 2  is a cutaway, side view of a threshold assembly according to one embodiment. 
         FIG. 3  is a perspective view of a threshold assembly according to one embodiment. 
         FIG. 4  is an exploded view of a threshold assembly according to one embodiment. 
         FIG. 5  is a top view of a threshold assembly according to one embodiment. 
         FIG. 6  is a front view of a threshold assembly according to one embodiment. 
         FIG. 7  is a bottom view of a threshold assembly according to one embodiment. 
         FIG. 8  is a rear view of a threshold assembly according to one embodiment. 
         FIG. 9  is a bottom view of a base according to one embodiment. 
         FIG. 10  is a perspective view of a base according to one embodiment. 
         FIG. 11A  is a side view of a cap according to one embodiment. 
         FIG. 11B  is a top view of a cap according to one embodiment. 
         FIG. 11C  is a bottom view of a cap according to one embodiment. 
         FIG. 12  is a side view of a threshold assembly according to one embodiment. 
         FIG. 13  is a perspective view of a threshold assembly according to one embodiment. 
         FIG. 14  is an exploded view of a threshold assembly according to one embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     The present invention will now be described more fully hereinafter with reference to the accompanying pictures in which exemplary embodiments of the invention are shown. However, the invention may be embodied in many different forms and should not be construed as limited to the representative embodiments set forth herein. The exemplary embodiments are provided so that this disclosure will be both thorough and complete and will fully convey the scope of the invention and enable one of ordinary skill in the art to make, use, and practice the invention. 
     Relative terms such as lower or bottom; upper or top; upward, outward, or downward; forward or backward; and vertical or horizontal may be used herein to describe one element&#39;s relationship to another element illustrated in the figures. It will be understood that relative terms are intended to encompass different orientations in addition to the orientation depicted in the drawings. By way of example, if a component in the drawings is turned over, elements described as being on the “bottom” of the other elements would then be oriented on “top” of the other elements. Relative terminology, such as “substantially” or “about,” describe the specified materials, steps, parameters, or ranges as well as those that do not materially affect the basic and novel characteristics of the claimed inventions as whole (as would be appreciated by one of ordinary skill in the art). 
     Disclosed is a threshold assembly that includes a base  10 , a nose cover  40 , a deck cover  60 , cap  100 , and an adjustment screw  50 . As described more fully below, the threshold assembly can be constructed so that the deck cover  60 , nose cover  40 , and cap  100  are all capable of being removed or installed without the need for tools, thereby making the threshold assembly easier for purposes of installation and/or repair. 
     In addition to being convenient to install and repair, the modular construction also allows the threshold assembly to accommodate entryways of varying dimensions. To illustrate, the adjustment screw  50  allows the height of the cap  100  to be adjusted so as to create an appropriate seal between the threshold assembly and the bottom of a door. The base  10  can be constructed in a modular fashion such that it can be cut to various widths to accommodate entryways of varying widths within a door frame. The deck cover  60  can be constructed so as to accommodate a threshold extender  140 , as shown in  FIG. 2 , that lengthens the threshold assembly as it extends from an entryway and that can be installed on the deck cover  60  without the need for special tools. 
     One or more of the deck cover  60 , threshold extender  140 , the nose cover  40 , the cap  100 , and base  10  can be made from thermoplastic materials that have superior mechanical, thermal, aesthetic, and other properties as compared to conventional threshold assemblies. As one example, the outside surfaces or “skin” of the deck cover  60 , threshold extender  140 , the nose cover  40 , and/or the cap  100  are made from a polymethyl methacrylate (“PMMA”) material. The PMMA material has the advantage of high tensile strength, scratch resistance, high ultraviolet (UV) light tolerance, chemical resistance, and PMMA can be processes using a variety of techniques, such as extrusion, injection molding, physical cutting, laser cutting, welding, among others. 
     The PMMA or other acrylic materials also have the advantage of good aesthetic qualities as it readily accepts pigments, is generally optically transparent, can be imprinted with designs, and is easy to clean owing to low surface tension that does not permit materials to stick to its surface. Thermoplastic materials can be formed with particular colors or patterns that extend through the entire material as opposed to a painted color coating. In this manner, the threshold maintains color in the face of not only potential damage from sunlight but also from mechanical damage (e.g., scratches, cracks, etc.) that might otherwise remove a color coating leading to a degradation in the aesthetic qualities of the threshold. 
     The heat resistance, chemical resistance, and impact resistance of PMMA, which is generally a brittle material, is enhanced using one or more impact modifiers where the impact modifiers can be, but are not limited to, acrylate monomers or acrylate polymers present in a range from 10% to 50% and preferably from 35% to 45%. The impact modifier can be comprised of, for instance, methyl methacrylate, methyl methacrylate-butadiene-styrene (“MBS”), polybutyl acrylate (“PBA”), or various polyacrylate polymers. In one embodiment, the components of the threshold assembly are formed using a thermoplastic material that is reinforced with nylon fibers, which can serve as an impact modifier and which are suited for use in an extrusion process, to provide enhanced mechanical performance, durability, and thermal resistance. One or more of these components can also be formed using a polyvinyl chloride (“PVC”) material either alone or with PMMA and impact modifiers. 
     In one embodiment, the outer skin of the deck cover  60 , the nose cover  40 , the cap,  100 , and/or threshold extender  140  are formed using a coextrusion process that relies on dual durometers to form an extradate composed of more than one thermoplastic melt stream, such as a thermoplastic base material (e.g., a PMMA based material with acrylate impact modifiers) melt stream and a PVC melt stream. The advantages of utilizing an extrusion process to form the outer surfaces as opposed to other processes, such as injection molding, include the ability to create laminar structures that are less porous with increased density, impact resistance, and resistance to shattering. 
     Those of skill in the art will appreciate that various types of thermoplastics can be used to form the components of the threshold assemblies disclosed herein, including, but not limited to, various acrylic monomers or polymers, acrylonitrile butadiene styrene (“ABS”), polylactide, polybenzimidazole (“PBI”), polycarbonate, polyether sulfone (“PES”), polyoxymethylene (“POM”), polyether ether ketone (“PEEK”), polyetherimide (“PEI”), polyethylene, polyphenylene oxide (“PPO”), polyphenylene sulfide (“PPS”), polypropylene, polystyrene, polyvinyl chloride (“PVC”), polyvinylidene fluoride, and Teflon. 
     In one exemplary embodiment, the base  10 , nose wall  30 , nose cover  40 , cap  100 , threshold extender  140 , or one or more of the other components are formed from a PVC composite material that includes (1) PVC; (2) calcium; (3) grindering material; (4) wood flour; (5) acrylic processing aid; (6)  118 A stabilizer; (7) stabilizer; (8) AC foaming agent; (9) white foaming agent; (10)  629  polyethylene wax; (11) polyethylene wax; and (12)  1801  stearic acid. Those of skill in the art will appreciate that the above composition can be varied to some degree while still achieving the benefits described herein. 
     In yet other embodiments, a PVC composite material can be used to form the bulk of the various components using injection molding or extrusion while the outer surface or skin of the components is formed using a combination of coextruded PMMA with impact modifiers and coextruded PVC. In this manner, the bulk portion of the components can be made from a lighter, cheaper material while the outer surfaces are made from more scratch resistant, shatter resistant, UV resistance, heat resistant, chemically resistant, and aesthetically advantageous material. 
     The use of injection molding to form various components has the advantage of permitting the formation of threshold components with more complex geometries. This in turn permits components to be formed with features that permit tool-free, snap fit assembly or features that save weight, such as cavities or cutouts, as illustrated in the attached figures and discussed below. The PVC composite materials can also be subjected to extrusion to form various components of the threshold assemblies, such as the unitary base components that are also shown in the attached figures, including  FIGS. 12-13 . 
     The enhanced properties of the acrylic or other thermoplastic materials are achieved while still reducing the cost of threshold manufacturing over conventional threshold materials. Conventional threshold materials, such as aluminum are costly and subject to sudden and wide price fluctuations, supply chain availability constraints in both the United States and overseas due to varying tariffs or regulatory barriers, and require additional costly processing steps during manufacturing, such as anodization. Thermoplastic materials have the advantage of avoiding such cost and supply chain constraints, and are less expensive and easier to process as they do not require anodization, and the cost of extruding or injection molding the materials to the desired form is significantly less than the cost of extruding aluminum. The acrylic and other thermoplastic materials used to form the thresholds disclosed herein are more durable, dent resistant, and lighter weight than existing threshold materials. The materials are also chemically resistant to a wide range of substances such that they are not subject to corrosion from paints, finishes, cleaners, various other construction or household materials. Thermoplastics in particular also have the advantages of being recyclable and capable of being remolded. 
     In some embodiments, the threshold components incorporate an UV light inhibitor that enhances resistance to damage and color fading from sunlight for up to ten years. The UV light inhibitor is provided as an additive to the thermoplastic materials. The composition of the UV light inhibitor can vary depending on the properties and composition of the thermoplastic materials used to form the threshold components as well as the particular cost concerns, among other factors. Suitable UV light inhibitors can include, for instance, combinations of carbon black, rutile titanium oxide, hydroxybenzophenone, hydroxyphenylbenzotriazole, oxanilides for polyamides, benzophenones for PVC materials, and benzotriazoles and hydroxyphenyltriazines for polycarbonate materials, or Hindered Amine Light Stabilizers (“HALS”), among other compounds known to those of skill in the art. 
     The improved thermal properties of the thermoplastic materials can create a thermal break that improves energy efficiency within the associated building structure. The thermoplastic materials have the additional advantage that they do not facilitate condensation as in conventional metallic thresholds, which can create a safety hazard as moisture collects on a threshold surface, thereby reducing friction and making the threshold slippery. 
     Turning the attached figures, one exemplary embodiment shown in  FIGS. 1 to 11  utilizes a base portion  10  that includes a bottom surface  12 , a front face  14  having a rabbeted front edge  16 , a top surface  18  having longitudinal and transverse support ribs  17  and a plurality of voids  15 , a sizing notch  19  adjacent to a fastener block  23 , a slit  21 , an attachment groove  22  having an attachment groove shoulder  24 , a base channel wall  25 , a channel  26 , a nose wall  30 , a nose groove  32 , and a nose wall recessed portion  34 . The top surface  18  is graded to facilitate the runoff of moisture from the threshold as well as to provide a smooth transition from the threshold to the surrounding ground area. The base channel  26  is sized to accommodate the cap  100 . 
     In some embodiments, the base  10  can be formed from plastic materials using injection molding techniques. Use of injection molding techniques has the advantage of relatively low cost and flexibility in the formation of various features of the base  10 , such as the voids  15 , support ribs  17 , sizing notch  19 , and slits  21 , among other features. Formation of the voids  15 , slits  21 , and the nose wall recessed portion  34  conserves materials during manufacturing and results in reduced weight during shipping to provide significant cost savings. The transverse and longitudinal support ribs  17  extend between the voids  15  to provide mechanical rigidity to support a deck cover  60  installed on the base  10 . 
     As shown more particularly in  FIG. 7 , the base  10  can be sized to accommodate threshold entryways of different widths by cutting the base  10  along one of the sizing notches  19  adjacent to one of the fastener blocks  23  to ensure there is some solid portion of the base  10  through which a fastener can be driven (i.e., the fastener block  23 ) to secure the threshold assembly within a door frame. 
     The deck cover  60  is secured to the base  10  through the rabbeted front edge  16  that is sized to accommodate a bottom flange  70  of the deck cover  60  and through the attachment groove  22  and groove shoulder  24  that are sized to accommodate a deck cover lower attachment wall  82  and lower attachment tab  83 . In this manner, the deck cover  60  can quickly and conveniently be removed and replaced prior to installation in a door frame by securing the bottom flange  70  of a new deck cover  60  about the rabbeted front edge  16  and snap fitting the lower attachment tab  83  into the attachment groove  22  so that it frictionally engages the groove shoulder  24 . The deck cover  60  rear wall includes a dam portion  84  and a dam portion tab  85  that is sized to fit within the cap portion channel  108  to prevent moisture intrusion within the threshold assembly and to secure the deck cover  60  to the cap  100 . The use of thermoplastic materials and the secure fit provided by the snap-fit assembly construction of the disclosed threshold assemblies eliminates or substantially reduces “deck chatter,” which are the cracking noises emanating from conventional threshold assemblies in response to an applied load when the materials used to construct the threshold are loosely fit together, brittle, or otherwise susceptible to mechanical movement and deflection producing unwanted noise. 
     A nose cover  40  can be secured about the nose wall  30  to protect the nose wall  30  against wear and tear. The nose cover  40  includes an arcuate attachment portion  42  that fits over the top of the nose wall  30  as well as a nose attachment tab  44  that fits within the nose groove  32  to secure the nose cover  40  in place over the nose wall  30 . 
     The deck cover  60  includes an upper tread surface  62  as a safety feature to militate against slipping of individuals and objects passing over the threshold. The deck cover  60  further includes a front deck cover face  64 , an interior channel  66 , a deck cover support wall  68 , a bottom flange  70 , a deck cover rabbeted portion  72 , and a deck cover nose  76  and nose cavity  74 . Formation of the deck cover  60  with an interior channel  66  saves material and weight during manufacturing and shipping, thereby making the deck cover  60  less expensive to manufacture and lighter weight for shipping and use. The deck cover support wall  68  adds rigidity and strength to the front portion of the deck cover  60 . 
     The deck cover nose  76  is rounded to help facilitate objects passing over the edge of the threshold onto the deck cover tread surface  62 . As force is applied to the deck cover nose  76  from a passing object or individual, the nose  76  deflects into the nose cavity  74 , which allows the deck cover nose  76  to bear additional loads without buckling or experiencing mechanical failure. The deck cover  60  is configured to accommodate a threshold extender  140 , as shown in  FIG. 2 , where the deck cover rabbeted portion  72  receives an extender tab  142 , and the nose cavity  74  receives an extender attachment projection  144 . 
     The threshold assembly cap  100  includes a cap body  103  defined by one or more sidewalls, a cap barrier portion  109 , a cap gasket  107  affixed to the inside of the barrier portion  109 , a cap interior cavity  102 , a cap top surface  104 , a top surface support ridge  105  to add strength and rigidity, a cap first leg  110 , a cap first leg rabbeted edge  111 , and a cap second leg  112  where both the cap first leg  110  and the cap second leg  112  define a cap recess  106 . 
     The cap barrier portion  109  defines a cap channel  108  that accommodates the dam portion  84  and dam portion tab  85 . When the dam portion  84  is seated within the cap channel  108 , the cap gasket  107  frictionally engages the dam portion  84  and serves to prevent moisture, particulate, or other contaminants from entering the threshold components. The cap first leg  110  and the cap second leg  112  are secured within the base channel  26  by frictionally engaging the deck cover channel wall  25  and the nose cover attachment portion  42 . Forming the cap with an interior cavity  102  and recess  106  saves material during manufacturing leading to a lower cost, lighter weight assembly. 
     The interior cavity  102  and recess  106  additionally serve to accommodate the adjustment screw  50  and washer  52  that can be used to vary the height of the cap  100 . The cap adjustment screw  50  is protected from mechanical damage and moisture intrusion by a cap screw cover  54 . The cap screw cover  54  is housed within a cap first passage  113  formed in the cap top surface  105  and that extends through to the cap interior cavity  102 . The cap adjustment screw  50  is housed within a cap second passage  115  formed in a surface of the cap recess  106  and that also extends through to the cap interior cavity  102 . In the overall door assembly, the cap top surface  104  frictionally engages the lower portion of the associated door or door sweep (not shown). By turning the adjustment screw  50 , the cap  100  and/or the cap screw cover  54  can be raised or lowered to ensure a proper fit between the threshold assembly and the door components. 
     The components of the threshold embodiment disclosed herein can be formed using any suitable means known to one of ordinary skill in the art, such as injection molding, extrusion, three-dimensional printing, or the like. Moreover, one or more of the parts components can be formed integrally with another component, or alternatively, split into a multitude of other separate components. For instance, the front portion of the deck cover  60  can be formed as a separate extender portion similar to the embodiment depicted in  FIG. 2  while remaining deck cover  60  components are formed as a separate component. Alternatively, as shown in  FIGS. 12 and 13 , the deck cover  60  can be formed integrally with the base portion  10 , or the base portion nose wall  30  can be formed integrally with the nose cap  40 . 
     In one embodiment, depicted in  FIGS. 12 and 13 , the base  10  is formed from a PVC composite material utilizing an extrusion process. The deck cover  60  is formed using a coextrusion process with two separate melt streams: (1) a first melt stream having a thermoplastic material, such as PMMA, with one or more impact modifiers, pigments; and (2) a second PVC melt stream. The thermoplastic and PVC melt streams may optionally include a pigment, UV inhibitor, or other additives to enhance material performance or aesthetic qualities. The two extruded melt streams form a single layer deck cover  60  that is bonded or laminated on the base  10  such that the base  10  and deck cover  60  form a unitary component. 
     A third extrusion melt stream of PVC material having a pigment additive is utilized to form the nose cover  40  that is also laminated or bonded to the nose wall  30  of the base to form a unitary component. The deck cover  60  and nose cover  40  can be secured or bonded to the base  10  using any suitable technique known to one of skill in the art, including, for example, lamination using heat, pressure, or adhesives to bond the components together. The cap  100  is formed from a PVC or PVC composite material using either injection molding or extrusion. 
     The unitary base  10 , deck cover  60 , and nose cover  40  structure has the benefits of reduced assembly time at an installation site, a reduction in the number of parts that may separate or loosen over time, and the elimination or substantial reduction of deck chatter, among other advantages. For instance, because the deck cover  60  shown in  FIGS. 12 and 13  is secured to the base  10 , the need for the attachment groove shoulder  24  and attachment groove  22  is eliminated. Even with the unitary construction, however, the coextrusion processes permit the formation of weight saving features, such as the base voids  15 , and the formation of useful features, such as the moisture barrier dam portion  84  and dam portion tab  85  and the nose  76  and nose cavity  74 . 
     In yet another embodiment shown in  FIG. 14 , the threshold assembly utilizes a combination of a solid block unitary PVC base  10  with a separable deck cover  60  and nose cover  40 . The base rabbeted front edge  16  is sized to accommodate the bottom flange  70  of the deck cover  60 , and the attachment groove  22  and groove shoulder  24  are sized to accommodate a deck cover lower attachment wall  82  and lower attachment tab  83  to secure the deck cover  60  to the block base  10 . The base channel  26  is sized to accommodate the cap  100  consistent with the other disclosed embodiments. The base  10  further includes a beveled portion  20  to better accommodate installation of the deck cover  60  and deflection of the deck cover  60  when subjected to a load. 
     Although the foregoing description provides embodiments of the invention by way of example, it is envisioned that other embodiments may perform similar functions and/or achieve similar results. Any and all such equivalent embodiments and examples are within the scope of the present invention.