Patent Publication Number: US-8966841-B2

Title: Adjustable door threshold

Description:
This application is a Divisional of Ser. No. 11/641,958, filed Dec. 20, 2006now U.S. Pat No. 8,186,114, the entire content of which is hereby incorporated by reference in this application. 
    
    
     FIELD OF THE INVENTION 
     Certain example embodiments of this invention relate a door threshold. More particularly, certain example embodiments of this invention relate to a door threshold that permits certain installation sequencing/issues to be controlled in varying degrees, addresses issues of security, and/or allows for improved practical uses. Door thresholds according to certain example embodiments of this invention may be used in the context of fire doors or any other suitable door application. 
     BACKGROUND AND SUMMARY OF EXAMPLE EMBODIMENTS OF THE INVENTION 
       FIG. 1  illustrates a known door threshold. In  FIG. 1 , threshold  1  serves as a carpet divider, is located under the door, and includes at least one overhang  3  under which carpet  4  and carpet pad  6  may be run. The  FIG. 1  threshold is typically made of aluminum. 
     Threshold  1  of  FIG. 1  requires the presence of carpet tacks  5  and supports  7  therefor proximate to the overhangs  3  in order to fasten down the carpet  4  so as to prevent the carpet from slipping out from over the overhangs  3 . However, if the carpet  4  wears out, or tears, tacks  5  tend to poke through the carpet and can be a hazard because they can injure feet of a person walking near the threshold. 
       FIG. 2  is a perspective view of a door threshold that reduces and/or eliminates the need for carpet tacks, thus representing an improvement over certain prior art systems. Thresholds of this type are disclosed in, for example, application Ser. No. 11/344,114, the entire content of which is hereby incorporated herein by reference. Threshold  10  may be of aluminum or the like. Threshold  10 , on one or both sides thereof, includes upper and lower members,  12  and  14  respectively, which sandwich an end of carpet  4  therebetween. As shown in  FIG. 2 , carpet pad  6  may stop short of the lower member  14  so that only the carpet  4  is sandwiched between the upper and lower members  12  and  14  in certain embodiments (although this need not be the case in all embodiments). In certain embodiments, at least parts of the upper and lower members  12  and  14  are substantially parallel (i.e., parallel plus/minus about 20 degrees) to one another. 
     In certain embodiments, upper and/or lower member(s)  12 ,  14  grip or otherwise maintain the carpet  4  that is located therebetween. Thus, the need for carpet tacks proximate to the threshold is reduced and/or eliminated because the threshold itself maintains the end of the carpet in position and reduces the ease with which it may be pulled out from between members  12 ,  14 . Overhang  12  may be flexible in certain embodiments, so as to provide a downward-directed biasing force against the carpet  4  to help maintain the end of the carpet between members  12  and  14 . The threshold further allows for a variety of different carpet and/or pad thicknesses, and can maintain a slight rise above the carpet for a door sweep to seal against and yet not rub or significantly rub on the carpet when closing. 
     Carpeting  4  typically is glued down or stretched and held by carpet tack strips along the walls. At the door opening, the carpet cannot be glued to a pad typically. The carpet tuck feature of threshold  10  effectively grips the carpet and reduces the ease with which it may be pulled away from the threshold. The carpet will have been stretched and held at either side of the door opening. 
     As shown in  FIG. 2 , the top surface  10   a  of the threshold  10  includes a peak or highest elevation portion  10   b . Then, the top surface  10   a  preferably slopes downwardly from peak  10   b  on both sides thereof to lower elevation portions  10   c . The top surfaces of lower elevation portions  10   c  typically are sloped from about 5 to 60 degrees, more preferably from about 10 to 35 degrees, relative to the a top flat portion of peak lob. Moreover, as shown in  FIG. 2 , the bottom member or base  14  of the threshold may be divided into two separate and distinct feet  14   a  and  14   b  that are separated from one another by gap or cavity  15 . Typically, the gap or cavity  15  is located under the peak portion  10   a  of the threshold. Feet  14   a ,  14   b  are preferably attached to the floor (or other support located over the floor) via an adhesive, screws, or the like. The door frame may be made of steel, aluminum, wood, or any other suitable material. 
     While the thresholds described with reference to  FIG. 2  are more advantageous than certain prior art thresholds, further improvements are still possible. For example, sometimes a stock threshold, also called a transition strip, is provided to allow for separating carpet colors and/or patterns. However, such stock transition strips do not account for the many variations in wall- and frame-depth. For example, current thresholds are made to a specific depth dimension and, as such, cannot effectively address the desire to have a single stock threshold span the many variations in wall- and frame-depth. Accordingly, many thresholds do not meet certain fire codes, some of which may require a true fire separation under the door and do not allow carpet-to-carpet detailing. 
     A typical opening where such problems arise may be, for example, a connecting room double-door setup (e.g. in a hotel), where it is desirable to span the entire frame depth. This arrangement is depicted in  FIG. 3 . Briefly, two doors  20   a - b  are provided for closing the entry way formed by walls  24   a - b . A threshold  22  is disposed between doors  20   a - b . As noted above, it would be advantageous to use a stock threshold to span the entire wall- and/or frame-depth. The threshold  22  would be set under doors  20   a - b  and have notches  26   a - d  for accommodating one or more stops  28   a - b.    
     Thus, it will be appreciated by those skilled in the art that there exists a need in the art for an improved door threshold(s). 
     One aspect of certain example embodiments relates to a door threshold structure comprising a main body formed from a male foot and a female foot. 
     Another aspect of certain example embodiments relates to a door threshold structure comprising a main body formed from two female feet connected via a center insert. Other components are also possible in certain instances. 
     Still another aspect of certain example embodiments relates to a door threshold structure comprising a main body formed from two feet butt-joined to a center insert. 
     Yet another aspect of certain example embodiments relates to a door threshold structure comprising a main body formed from one foot joined to a riser. 
     Accordingly, in certain example embodiments, a door threshold structure to be at least partially located underneath at least one door when the at least one door is in a closed position, in combination with a carpet is provided. A first foot and a second foot may be configured to be connected (directly or indirectly) to form a main body of the door threshold structure. The first foot may include a protrusion formed thereon for engaging with a recession in the second foot. On at least one side of said main body there may be provided upper and lower members extending from the main body in spaced apart relation from one another so that the upper and lower members may be at least partially substantially parallel to one another. The carpet may be located adjacent to the threshold. A gap between the spaced apart upper and lower members may be configured to receive an end of said carpet. 
     In certain other example embodiments, a door threshold structure to be at least partially located underneath at least one door when the at least one door is in a closed position, in combination with a carpet, is provided, wherein the door threshold structure may comprise a first foot and a second foot configured to be connected via a center insert to form a main body of the door threshold structure. On at least one side of said main body there may be provided upper and lower members extending from the main body in spaced apart relation from one another so that the upper and lower members are at least partially substantially parallel to one another. The carpet may be located adjacent to the threshold. A gap between the spaced apart upper and lower members may be configured to receive an end of said carpet. 
     According to certain other example embodiments, a a door threshold structure to be at least partially located underneath at least one door when the at least one door is in a closed position, in combination with a carpet, is provided, and the door threshold structure may comprise a foot configured to be connected to a riser to form a main body of the door threshold structure. On one side of said main body there may be provided upper and lower members extending from the main body in spaced apart relation from one another so that the upper and lower members are at least partially substantially parallel to one another. The carpet may be located adjacent to the threshold. A gap between the spaced apart upper and lower members may be configured to receive an end of said carpet. 
     The upper member may be flexible and an end thereof may be biased downwardly toward an end of the bottom member in order to grip carpet located between the upper and lower members. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       These and other features and advantages will be better and more completely understood by reference to the following detailed description of exemplary illustrative embodiments in conjunction with the drawings, of which: 
         FIG. 1  is a perspective view of a conventional door threshold structure; 
         FIG. 2  is a perspective view of a door threshold that reduces and/or eliminates the need for carpet tacks (note that tacks are still possible in certain example embodiments of this invention); 
         FIG. 3  is a top-view of a connecting room double-door setup; 
         FIG. 4   a  is a perspective view of an adjustable threshold having a male-female connector, in accordance with an example embodiment; 
         FIG. 4   b  shows an adjustable threshold similar to the configuration described with reference to  FIG. 4   a , except the gap of  FIG. 4   a  is substantially filled in by one or more layers, in accordance with an example embodiment; 
         FIG. 4   c  is an adjustable threshold similar to the configuration described with reference to  FIG. 4   a , except the protrusion is shown as having a series of barbs for engaging with interlocking barbs disposed on the female foot, in accordance with an example embodiment; 
         FIG. 5   a  is a perspective view of an adjustable threshold having a female-female connector for accommodating a center bridge insert, in accordance with an example embodiment; 
         FIGS. 5   b - e  are perspective views of adjustable thresholds having female-female connectors for accommodating one or more center layers, in accordance with an example embodiment; 
         FIG. 6   a  is an illustrative center bridge insert  36 , which may be used in conjunction with thresholds according to  FIG. 5   a;    
         FIG. 6   b  shows multiple illustrative interlocking center bridge inserts  36 , which may be used to further vary the depth of the threshold, in accordance with an example embodiment; 
         FIG. 7  is an adjustable threshold for use with an optional riser, in accordance with an example embodiment; and, 
         FIG. 8  is yet another adjustable threshold, in accordance with an example embodiment. 
     
    
    
     DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS OF THE INVENTION 
     Referring now more particularly to the drawings in which like reference numerals indicate like parts throughout the several views,  FIG. 4   a  is a perspective view of an adjustable threshold having a male-female connector, in accordance with an example embodiment. As shown in  FIG. 4   a , the adjustable threshold is positioned under two doors  20   a - b  which may be, for example, a fire door and a non-fire rated door, respectively. Of course, it will be appreciated that either, both, or neither door need be a fire door. Top portion  35   e  of the adjustable threshold is located between doors  20   a - b , and corresponds to the viewable portion of threshold  22  shown in  FIG. 3 . 
     The heights of doors  20   a - b  optionally may be adjustable, for example, via adjustment mechanisms  30 . Also, brushes (or sweep)  30   a  optionally may be located at the bottom of doors  20   a - b  and project downwards towards the adjustable threshold, for example, to at least partially seal (e.g. provide insulation, protection, separation, or the like between) adjacent areas. Like the threshold of  FIG. 2 , the adjustable threshold of  FIG. 4   a  may include upper and lower members,  35   f - g , respectively, which sandwich an end of carpet  4  therebetween. Carpet pad  6  may stop short of the lower member  35   g  so that only the carpet  4  is sandwiched between the upper and lower members  35   f - g  in certain example embodiments (although this need not be the case in all example embodiments). In certain example embodiments, at least parts of the upper and lower members  35   f - g  are substantially parallel (i.e., parallel plus/minus about 20 degrees) to one another. 
     In certain embodiments, upper and/or lower member(s)  35   f - g  grip or otherwise maintain the carpet  4  that is located therebetween. Thus, the need for carpet tacks proximate to the threshold is reduced and/or eliminated because the adjustable threshold itself maintains the end of the carpet in position and reduces the ease with which it is pulled out from between members  35   f - g . While tacks are not needed in such areas in certain example instances, it is possible that tacks may be provided in other example embodiments of this invention. Upper member  35   f  may be flexible in certain embodiments, so as to provide a downward-directed biasing force against the carpet  4  to help maintain the end of the carpet between members  35   f - g . The threshold further allows for a variety of different carpet and/or pad thicknesses, and can maintain a slight rise above the carpet for a door sweep to seal against and yet not rub or significantly rub on the carpet when closing. 
     Carpeting  4  typically is glued down or stretched and held by carpet tack strips along the walls. At the door opening, the carpet cannot be glued to a pad typically. The carpet tuck feature of the adjustable threshold effectively grips the carpet and reduces the ease with which it may be pulled away from the threshold. The carpet will have been stretched and held at either side of the door opening. 
     As shown in  FIG. 4   a , the adjustable threshold may be divided into two separate and distinct feet  35   a - b  that are separated from one another by gap or cavity  15 . Feet  35   a - b  may be attached to the floor (or other support located over the floor) via an adhesive (accommodated by notches  32 ), screws, or the like. Feet  35   a - b  also may be counter-sunk into the floor. As shown in  FIG. 4   a , foot  35   a  has protrusion  35   c  for engaging with a corresponding recession formed in foot  35   b . Optionally, a flange  35   d  is formed over a recession into which protrusion  35   c  may be inserted. Flange  35   d  is optional, though it may help smooth the joint between the foot and the protrusion. Thus, feet  35   a - b  may form a threshold via a male-female connection (e.g. a connection between foot  35   a  having a male protrusion, and foot  35   b  having a female recession). Foot  35   a  optionally may be formed to have a piece corresponding to the size, shape, and/or location of flange  35   d  (e.g. for aesthetic purposes). Protrusion  35   d  may slide into the recession of foot  35   b . Alternatively, certain example embodiments may not have flange  35   d  located on foot  35   b , and protrusion  35   c  may simply rest on the recession (which may be thought of as a notch) formed within foot  35   b . Protrusion  35   d  may be connected to foot  35   b  using, for example, one or more of an adhesive, screws, etc. Some or all of protrusion  35   c  may be shortened (e.g. cut) to customize the depth of the assembled threshold. It has been determined that a protrusion of approximately  10 ″ covers most implementations, though the invention is not so limited. Additionally, or in the alternative, several stock male feet  35   a  having varying lengths for protrusion  35   c  may be provided, and a close (or closest) foot may be chosen in a particular example. 
       FIG. 4   b  shows an adjustable threshold similar to the configuration described with reference to  FIG. 4   a , except gap  15  of  FIG. 4   a  is substantially filled in by one or more layers  31 , in accordance with an example embodiment. The one or more layers  31  for filling in gap  15  of  FIG. 4   a  may be made of the same material as the threshold, or any other suitable material. Also, the one or more layers  31  may be provided to supply additional support under protrusion  35   c  (e.g. at the substantially flat portion  35   e  located between doors  20   a - b ), which may be advantageous in certain embodiments where the depth of the assembled threshold is large. 
       FIG. 4   c  is an adjustable threshold similar to the configuration described with reference to  FIG. 4   a , except protrusion  35   c  is shown as having a series of barbs  33   a  for engaging with interlocking barbs  33   b  disposed on female foot  35   b , in accordance with an example embodiment. Barbs  33   a  optionally may be angled towards male foot  35   a , and barbs  33   b  optionally may be angled towards female foot  35   b  at substantially the same angle, thus forming an interlocking mechanism. In certain example embodiments, the interlocking barbs  33   a - b  may establish a substantially permanent connection, although the present invention is not so limited. Additionally, rather than disposing barbs, a ribbed surface (or corresponding ribbed surfaces) may be disposed on female foot  35   b  (and/or on protrusion  35   c ) for establishing a similar connection between feet  35   a - b . Barbs  33   a - b  may be flexible in at least one direction, for example, to allow the feet  35   a - b  to be slid together depth-wise. Alternatively, barbs  33   a - b  may be rigid, potentially requiring the feet  35   a - b  to be slid together lengthwise. It will be appreciated that interlocking barbs  33   a - b  and/or ribbed surfaces may be used in place of, or in addition to, other attachment mechanisms (e.g. an adhesive, screws, etc.). In certain example embodiments, protrusion  35   c  and/or female foot  35   b  may be machined to have interlocking barbs  33   a - b , whereas interlocking barbs  33   a - b  may be affixed to protrusion  35   c  and/or female foot  35   b  after the main pieces are formed in certain other example embodiments. 
       FIG. 5   a  is a perspective view of an adjustable threshold having a female-female connector for accommodating a center bridge insert, in accordance with an example embodiment. The example embodiments described with reference to  FIG. 5   a  are similar to those described with reference to  FIG. 4   a . In  FIG. 5   a , however, two female feet  35   b  are provided, each having recessions. A center bridge insert  36  may effectively join female feet  35   b . As in  FIG. 4   a , flange  35   d  on each female foot  35   b  may help to form the recessions in each female foot  35   b . The area between the two flanges  35   d  is a flat top portion  36   a  of center bridge insert  36 . As above, it will be appreciated that flanges  35   d  are optional, and that center bridge insert  36  may simply rest on recessed (e.g. notched-out) portions of each female foot  35   b . Also, as above, the center bridge insert  36  may be connected to each female foot  35   b  by using, for example, one or more of an adhesive, screws, etc., and it covers gap  15 . 
       FIGS. 5   b - e  are perspective views of adjustable thresholds having female-female connectors for accommodating one or more center layers, in accordance with an example embodiment. In  FIGS. 5   b - c , a cavity for receiving a center bridge insert need not be formed in each female foot  35   b ′. For example, in  FIG. 5   b , a first layer  31  may support a second layer  36 ′. Second layer  36 ′ may be, for example, marble, granite, wood, or any other type of decorative or non-decorative material. Flanges  35   d  may extend at least partially over the second layer  36 ′. Second layer  36 ′ may simply lie on top of first layer  31 , and/or they may be attached (e.g. via an adhesive, screws, etc.) to each other and/or to each foot  35   b′.    
     It will be appreciated that first layer  31  is optional, as shown by  FIG. 5   c , which simply has a large second layer  36 ′ in its place. Similarly, it will be appreciated that multiple first layers  31  may be used in connection with certain example embodiments. This arrangement is shown in  FIGS. 5   d - e .  FIG. 5   d  shows an embodiment with flanges  35   d , while such flanges are not present in the  FIG. 5   e  embodiment. 
     The embodiments described with reference to  FIGS. 5   b - c  may be suitable for carpet-to-hardwood connections. In particular, by cutting back the on the base of a female foot  35   b ′, the flooring may slide under the overhang, and the carpet may be tucked into the encapsulating female foot  35   b ′. Thus, an elevated transition may be created, keeping both materials on both sides of the adjustable thresholds substantially level. 
       FIG. 6   a  is an illustrative center bridge insert  36 , which may be used in conjunction with thresholds according to  FIG. 5   a , and  FIG. 6   b  shows multiple illustrative interlocking center bridge inserts  36 , which may be used to further vary the depth of the threshold, in accordance with an example embodiment. Center bridge insert  36  may be formed from any suitable material, such as, for example, a fire-rated PVC, the same material as foot  35   b , wood, etc., and it may be, for example, about 0.25″ thick. Optionally, center bridge insert  36  may be extruded in color. Also, center bridge insert  36  may include teeth  39  disposed on the surface facing away from door(s). These teeth may engage with one or more layers  31  (not shown) to provide a mechanical connection therebetween, and/or help accommodate an adhesive disposed between layers. 
     A center bridge insert  36  may have opposing end connectors  38   a - b  such that an end connector  38   a  of a first center bridge insert is configured to engage with an end connector  38   b  of a second center bridge insert  36 . Thus, the depth of the threshold may be varied by including one or more center bridge inserts  36 . Also, opposing end connectors  38   a - b  may be further held together using an adhesive, screws, or the like, for example, to reduce bowing, add structural support, etc. Alternatively or in addition, a center bridge insert  36  may be cut to vary the depth of the threshold (similar to the way in which protrusion  35   c  of  FIG. 4   a  may be cut)—e.g. a single center bridge insert  36  may be provided and optionally cut to an appropriate size, or multiple center bridge inserts  36  may be provided and one or more optionally may be cut to an appropriate size. It will be appreciated that the present invention is not limited to the end connectors shown in  FIGS. 6   a - b . Also, rather than; or in addition to, providing end connectors, multiple center bridge inserts  36  may be welded together to form a connection therebetween. 
       FIG. 7  is an adjustable threshold for use with an optional riser, in accordance with an example embodiment. Flange  35   d  optionally extends from adjustable threshold  40 , forming a recession thereunder. Riser  42  may be disposed against this recession. As shown in  FIG. 7 , riser  42  is disposed substantially against threshold  40 , although the invention is not so limited. For example, riser  42  may have a protruding member (not shown) for engaging with a recession formed within threshold  40  (e.g. similar to female foot  35   b  of  FIG. 5   a ). Additionally, threshold  40  and riser  42  may be more securely connected using, for example, an adhesive, screws, etc. Riser  42  may vary in dimensions such as, for example, height, slope, etc., depending on the particular needs and/or confines of the space, handicapped accessibility codes, etc. Riser  42  may be formed from any suitable material, such as, for example, wood, metal, plastic, ceramics, tiles, stone (marble, granite, etc.), etc. 
     In an example embodiment not shown, a smaller riser  42  may be provided, and tile, carpet, etc. may be disposed on top of it. One example riser  42  that is believed to be compliant with relevant disability laws has a length of about 12″, a height of about 0.25″, and thus a rise of about 1.19 degrees; although, the present invention is so not limited to this arrangement. 
       FIG. 8  is yet another adjustable threshold, in accordance with an example embodiment. Each foot  45  has a substantially flat inner surface  45   a . Within opposing inner surfaces  45   a , one or more first layers  31  and one or more second layers  36  may be provided. First layer(s)  31  and/or second layer(s)  36  may be cut to an appropriate size to vary the depth of the adjustable threshold. Alternatively, or in addition, a number of differently sized stock first layer(s)  31  and/or second layer(s)  36  may be provided to vary the depth of the adjustable threshold. 
     The example embodiments described herein may be further customized. For example, standard lengths may be provided and/or cut to a desired length. Optional risers may be disposed so as to increase the height from the floor to the top of the threshold, for example, to accommodate tile, hardwood, or the like; to receive a sub-floor leveler (e.g. made by flooring manufacturers to transition for ADA purposes); etc. The example embodiments described herein also may be used for other purposes. For example, adjustable thresholds may be used in cases where abutting carpets stop short of each other (e.g. where a hallway carpet stops short of a room&#39;s carpeting). 
     While the invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not to be limited to the disclosed embodiment, but on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.