Wedge tread stair box system

Abstract

A stair box system made of a stair box core, stringers, risers and treads. The inner surfaces of the stringers have a discontinuous series of mortises positioned to engage only with the treads. Each tread is beveled from the front to back surfaces and each of the riser is beveled from the top to the bottom surface. Each tread features one or more notches cut into its back surface and each riser includes a complementary hook cut into its bottom surface. The hooks on the risers engage the notches on the treads forming an open-faced channel. Removable covers fit over the treads of the stair box core. These covers protect the stair box core and/or they feature decorative building materials like hardwood or tile. The system allows the user to upgrade their stairs by replacing the covers with covers featuring a different finished surface.

Claims

1. A stair box system comprising: two stringers each with a surface featuring a plurality mortises; a first plurality of risers each having a top surface, a bottom surface, a front surface, a back surface and two side surfaces; wherein each riser is beveled from the top surface to the bottom surface such that the top surface is wider than the bottom surface; a first plurality of treads having a front surface, a back surface, a top surface, a bottom surface and two side surfaces; wherein each tread is beveled from the front surface to the back surface such that the front surface is wider than the back surface; and wherein each side surface of each tread is configured to engage with the plurality of mortises featured on the stringers.

2. The stair box system of claim 1 further comprising: a first plurality of removable covers, each configured to fit over and cover the top surface of a single tread of the first plurality of treads, each removable cover comprising: a tread having a front surface, a back surface, a top surface, a bottom surface and two side surfaces; wherein each tread is beveled from the front surface to the back surface such that the front surface is wider than the back surface.

3. The stair box system of claim 1 wherein each tread of the first plurality of treads features at least one notch cut into the back surface of each tread and each riser of the first plurality of risers features at least one hook cut into the bottom surface of the riser; wherein each hook on each riser is configured to engage with the notch on each tread.

4. The stair box system of claim 3 wherein the hooks and notches form a groove configured to accept a separate length of material.

5. The stair box system of claim 2 wherein the top surface of each tread of the plurality of removable covers includes a pre-finished material.

6. The stair box system of claim 5 further comprising a second plurality of removable covers, wherein each removable cover of the second plurality of removable covers is configured to fit over and cover the front surface of a single riser of the first plurality of risers, each removable cover of the second plurality of removable covers comprising: a riser having a front surface, a back surface, a top surface, a bottom surface and two side surfaces; wherein each riser is beveled from the top surface to the bottom surface such that the top surface is wider than the bottom surface.

7. The stair box system of claim 6 wherein the front surface of each riser of the second plurality of removable covers features a pre-finished material.

8. The stair box system of claim 2 wherein each tread on each of the plurality of removable covers features a mortised nose attached to the front surface of each tread and wherein the mortised nose is a different color than the plurality of the treads.

9. The stair box system of claim 4 further comprising: a first plurality of removable covers, each configured to cover the top surface of a single tread of the first plurality of treads, each removable cover comprising: a tread having a front surface, a back surface, a top surface, a bottom surface and two side surfaces; wherein each tread is beveled from the front surface to the back surface such that the front surface is wider than the back surface; and wherein each removable cover is configured to fit over and cover the top surface of a single tread of the first plurality of treads.

10. The stair box system of claim 9 further comprising a second plurality of removable covers, wherein each removable cover of the second plurality of removable covers is configured to fit over and cover the front surface of a single riser of the first plurality of risers, each removable cover of the second plurality of removable covers comprising: a riser having a front surface, a back surface, a top surface, a bottom surface and two side surfaces; wherein each riser is beveled from the top surface to the bottom surface such that the top surface is wider than the bottom surface.

11. A stair box assembly comprising: two stringers each with an inner surface featuring a plurality mortises; a spacer board attached to an outer surface of each of the stringers; a first plurality of risers each having a top surface, a bottom surface and two side surfaces, said risers being tapered from the top surface to the bottom surface such that the top surface is wider than the bottom surface; a first plurality of treads having a front surface, a back surface, a top surface, a bottom surface and two side surfaces, said treads being tapered from the front surface to the back surface such that the front surface is wider than the back surface; wherein each tread of the first plurality of treads features at least one notch cut into the back surface of each tread and each riser of the first plurality of risers features at least one hook cut into the bottom surface of the riser and each hook is configured to engage with the at least one notch on each tread; and wherein when the risers and treads are engaged, the hooks form a channel on an underside of the stair box, said channel being configured to accept a length of material; and wherein the plurality of mortises are configured to engage with the side surfaces of the treads; a first plurality of removable covers, wherein each cover is configured to fit over and cover a single tread of the first plurality of treads.

12. The stair box system of claim 11 further comprising a second plurality of removable covers, each removable cover of the second plurality of removable covers is configured to fit over and cover a single tread of the first plurality of treads; wherein each of the second plurality of removable covers has a top surface that features a pre-finished material.

13. The stair box assembly of claim 12 further comprising a third plurality of removable covers, each removable cover of the third plurality of removable covers is configured to fit over and cover a single riser of the first plurality of risers; wherein each of the third plurality of removable covers has a front surface that features a pre-finished material.

14. A method of installing a pre-finished material on the stair box of claim 13 comprising: placing each of the first plurality of removable covers over the top surface of each of the treads of the first plurality of treads; detaching each of the first plurality of removable covers from each tread of the first plurality of treads; sliding each of the covers of the second plurality of removable covers over the top surface of a single tread of the first plurality of treads; sliding each of the covers of the third plurality of removable covers over the front surface of a single riser of the first plurality of risers; removably attaching each of the covers of the second plurality of removable covers to the tread it covers; and removably attaching each of the covers of the third plurality of removable covers to the riser it covers.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

(1) FIG. 1A is a top plan view of the various components of the stair box system;

(2) FIG. 1B is a top plan view of the treads and risers thereof;

(3) FIG. 2A is a top perspective view of the various components thereof;

(4) FIG. 2B is a top plan view of the covers thereof;

(5) FIG. 3 is a top perspective view of an assembled stair box core;

(6) FIG. 4 is an exploded view of the stair box system showing the removable covers;

(7) FIG. 5 is a bottom perspective view of an assembled stair box core; and

(8) FIG. 6 is an additional bottom perspective view of an assembled stair box.

DETAILED DESCRIPTION OF THE INVENTION

(9) Referring now to the invention in more detail, in FIG. 1 there is shown the basic components of the inventive stair box system. More specifically, each stair box system, generally 10, in its most basic form is comprised of stringers 11, treads 12 and risers 13. FIG. 1A shows each of four stringers 11, two of them in each of two orientations. That is to say that each stringer 11 has a, inner surface 11a and an outer surface 11b. The inner surface 11a of each stringer 11 has mortises 14 cut into it. The outer surface of each stringer 11 does not have mortises 14 cut into it. FIG. 1 also shows a tread 12 and a riser 13. Each tread has a front surface 12a, a back surface 12b, two side surfaces 12c, a top surface 12d and a bottom surface (not shown). Similarly, each riser 13 has a front surface 13a, a back surface (not shown), two side surfaces 13c, a top surface 13d and a bottom surface 13e. Note that the tread 12 features one or more notches 15 on its back surface. Similarly, each riser 13 features one or more hooks 16 on their back surface 13b. The hooks 16 and notches 15 are complementary, i.e., configured to engage securely with each other when the stair box core 23 is assembled.

(10) FIG. 1B shows the treads 12 and risers 13 with the beveling exaggerated to make it more visually obvious. Each tread 12 has a front surface 12a, a back surface 12b, two side surfaces 12c, a top surface 12d and a bottom surface (not shown). Each tread 12 is beveled from then front surface 12a to the back surface 12b such that the front surface is wider than the back surface 12b that features the notches 15. Similarly, each riser 13 has a front surface 13a, a back surface (not shown), two side surfaces 13c, a top surface 13d and a bottom surface 13e. Each riser is beveled form the top surface 13d to the bottom surface 13e such that the top surface 13d is wider than the bottom surface 13e.

(11) FIG. 2A provides perspective views of the treads 12 and risers 13. Each tread 12 has a front surface 12a, a back surface 12b, a top surface 12d, a bottom surface (not shown) and two side surfaces 12c. Similarly, each riser features a front surface 13a, a back surface (not shown), a top surface 13d, a bottom surface 13e and two side surfaces 13c. As described above, the risers 13 each feature one or more hooks 16 and the treads 12 feature one or more notches 15. In preferred embodiments and the contemplated best mode, each riser 13 features two hooks 16 and each tread 12 features two notches 15. FIG. 2A also shows a tread cover 17 each with a front surface 17a, a back surface 17b, two side surfaces 17c, a top surface 17d and a bottom surface (not shown).

(12) FIG. 2B shows examples of both tread and riser covers 17 with the beveling exaggerated to make it more visually obvious. More specifically, FIG. 2B shows a tread cover 17 each with a front surface 17a, a back surface 17b, two side surfaces 17c, a top surface 17d and a bottom surface (not shown). The tread cover 17 has a front surface 17a that is wider than its back surface 17b as previously discussed. In addition, FIG. 2B shows a riser cover 27 each with a front surface 27a, a back surface (not shown), a top surface 27d, a bottom surface 27e and two side surfaces 27c wherein the top surface 27d is wider than the bottom surface 27e.

(13) In addition, FIG. 2 also shows the nose 18 that can be installed on the treads 12, particularly those treads 12 that are part of the safety cover (not shown). The nose 18 features a mortise 19 and the tread features a lip or tenon 20 that fits into the mortise 19 on the nose 18. This nose 18 is painted or otherwise features a color that makes the nose 18 more visible to someone walking up or down the stairs. FIG. 2 also shows a structural difference presented by versions of the stair box system 10 that are open, i.e., each side of the stair box is not flanked by a wall. In those embodiments, a mortised return 21 is fitted to the side surface 12c of each tread 12 such that the open side of the stair box features a return on most or all of the treads 12.

(14) FIG. 3 shows a perspective view of an assembled stair box core 23 with tread covers 17 in place featuring safety noses 18. The stair box core 23 is formed from two stringers 11, a plurality of treads (hidden from view by the trade covers 17) and a plurality of risers 13. The components of the stair box core 23 are joined together using traditional fasteners such as screws, nails, nuts and bolts, adhesives, etc. with screws being the preferred means of attachment in the contemplated best mode. The stair box core 23 contains two opposing stringers 11 forming the sides of the stair box core 23. Each stringer 11 has an inner surface 11a that faces towards the opposing stringer 11 and engages with the treads (not shown). Each stringer 11 also has an outer surface (not shown) that faces away from the opposing stringer 11 and treads 12. The outer surface of the assembled stair box core 23 can have attached to it a spacer board 22 meant to engage with a wall surface (not shown) such as a sheet of sheet rock. Returning to the stringers 11, the inner surfaces 11a of the stringers 11 have a discontinuous series of mortises (not shown) positioned to engage with the treads (not shown) and not the risers 13. In preferred embodiments, the mortises are cut to a uniform depthit is the tapering of the treads and/or the risers 13 that gives the stair box core 23 its unique shape. The components of the stair box core 23 are preferably cut using a CNC machine. As discussed above each of the treads is beveled or tapered from the front to the back surfaces, i.e. the front surface 12a of each tread is a little bit wider than the back surface 12b of each tread. Similarly, each of the risers 13 is tapered or beveled in the similar mannerfrom the top surface 13d to the bottom surface 13e, i.e., the top surface 13d is a little but wider than the bottom surface 13e. During assembly of the stair box core 23, the treads are engaged in the mortises present on the inner surfaces 11a of the stringers 11. The risers 13 are removably fixed to the treads using conventional fasteners, preferably screws. The risers 13, treads 12 and stringers 11 form the base or subfloor of the stairway to which carpeting, hardwood or other materials can be attached to form a finished staircase.

(15) In practice, the stair box core 23 is assembled off-site and shipped to the construction site to be installed. While construction is underway, the inventor anticipates the construction crew will install safety covers 24 made of whatever material is both durable and cheap such as pressed wood or plywood. The safety covers 24 can consist of covers for the risers 13 and the treads 12, but the inventor's contemplated best mode only includes tread covers 17. In other words, the safety covers 24 can be thought of as a type of tread cover 17, usually featuring a nose 18. The safety covers 24 can be attached to the stair box core 23 with conventional fasteners such as screws, nails, nuts and bolts, adhesives, etc. with screws being the preferred means of attachment. Just as the treads 13 described above, the safety covers 24 are beveled or tapered such that the front surface of the cover is a little bit wider than the back surface of the safety cover. As a result, they are meant to be slid over the surface of the treads 12 that are part of the stair box core 23 and when they are slid in place, the safety cover 24 fits snugly in place as it is beveled or tapered to the same degree as the underlying tread 12 of the stair box core 23.

(16) If desired, the safety covers 24 can feature noses 18 as described previously. With the safety covers 24, the noses 18 are preferably painted a bright color that does not match or blend into the wooden surface to ensure the construction crew can easily see the edge of each tread 12 as they are using the stairs while they are working. Later, when the rest of the construction is complete, the dry wall has been installed and painted and the other finish and trim work has been completed, the construction crew can detach and remove the safety covers 24 from the stair box core 23 and install pre-finished tread covers (not shown) which are essentially tread covers 17 that feature whatever desired building material on its outer surfaces the builder or homeowner requires whether it be a species of hardwood, tile, stone work or other decorative surface. The pre-finished covers are configured to slide into place over the treads of the stair box core 23 and separate pre-finished covers are configured to slide in place over the risers 13 of the stair box core 23. The pre-finished covers, like the underlying treads and risers 13 of the stair box system 10 are beveled or tapered to fit into place over the treads 12 and risers 13 of the stair box core 23.

(17) FIG. 4 shows and exploded view of the assembled stair box system 10 featured in the previous figure. As previously discussed, each stair box core 23 is made of two stringers 11, a plurality of treads 12 and a plurality of risers 13. The contemplated best mode of this system also includes spacer boards 22 fixed to the outer surfaces 11b of the stringers 11. FIG. 4 also shows the tread covers 17 both in place on the treads 12 and exploded away from the treads 12. As can be seen in FIG. 4, the tread covers 17 slide in place over the treads. First, the user places the back surface 17b of the tread cover 17 in contact with the top surface 12d of the tread 12 and then sliding the bottom surface 17e of the tread cover 17 over the top surface 12d of the tread 12 until the back surface 17b of the tread cover 17 contacts the riser 13. As previously discussed, the tread covers 17 that are used to cover and protect the treads 17 can be safety covers 24 or pre-finished covers 25. The difference between the two is both structural and functional. The tread covers that feature decorative material such as hardwood, are pre-finished covers 25. They are typically made of two layers of laminate with one layer of pressed wood, plywood or some other material sandwiched in between the laminate layers. They can be used to produce the final finished look of the stairs. In contrast, the safety covers 24 do not feature decorative materials and are in place for the purpose of protecting the stair box core 23. Both can feature a nose 18 as previously described.

(18) FIG. 5 shows the underside of the stair box core 23. As discussed above, each tread 12 of the stair box core 23 features one or more notches 15 cut into its back surface 12b and each riser 13 includes one or more complementary hooks 16 cut into its bottom surface 13e. When the risers 13 and treads 12 are assembled into the stair box core 23 the treads 12 are attached to the stringers 11 after fitting their side surfaces 12c into the mortises 14 cut into each stringer's inner surface 11a. As the risers 13 are installed and attached to the treads 12, the hooks 16 on the risers 13 engage the notches 15 on the treads 12 forming an open faced channel 26 or groove on the underside of the stair box core 23 that can accept a separate structure 27.

(19) FIG. 6 shows the underside of the same stair box core 23 with the piece of material or separate structure 27 removed from the open faced channel 26. As discussed above, each tread 12 of the stair box core 23 features one or more notches 15 and each riser 13 includes one or more complementary hooks 16. When the risers 13 and treads 12 are assembled into the stair box core 23 the treads 12 are attached to the stringers 11. As the risers 13 are installed and attached to the treads 12, the hooks 16 on the risers 13 engage the notches 15 on the treads 12 forming an open faced channel 26 or groove on the underside of the stair box core 23 that can accept a separate structure 27 such as a length of wood. This configuration adds stability to the stair box 23 through the use of a structure 27 that can be easily removed without partially disassembling the stair box 23.

(20) This stair box system represents a significant departure from the prefabricated stair boxes that are already on the market. Specifically, all of the pieces and parts of this system can be cut using CNC machining thus reducing the amount of manual labor required to produce a prefabricated stair box. In addition, using CNC machining also helps to decrease the incidence of workplace injuries. It also allows for more efficient use of the building materials, generally lumber, as the process can be used to cut multiple components from a single sheet of lumber. For example, the strip of lumber that fits into the open faced channel formed by the hooks and notches on the risers and treads can be made from scrap lumber.

(21) In addition, the system offers a number of obvious advantages over traditional prefabricated stair boxes. First, the treads and risers can be replaced without doing significant damage to the stair box and surrounding walls. Second, the stair box can be protected from weather and the elements while the building it is seated in is constructed. In addition, as mentioned above, the ability to change the surfaces of the treads and risers after the rest of the building has been constructed and the finish work has been completed decreases construction time and costs. Fourth, the spacer allows for the drywall or sheet rock or to be put in place to form the walls around the stair box more easily as the wall material need not be cut to fit over each individual stair.

(22) Moreover, the system makes it easy to use a color coding system to identify the sizes of materials needed to replace the treads and risers when the owner desires to replace the flooring or other material covering the stairs. More specifically, one color is used to identify the width of the treads and risers, another color is used to identify the depth or run of each of the treads and a third color is used to identify the rise or height of each of the risers. As a result, the owner can pull up the carpet or detach a single tread, note the colors painted on a surface of the stair box and then order the appropriate materials to replace the treads and risers with a new pre-finished surface. Above and beyond any other feature, this system is highly and easily customizable.

(23) Reference throughout the specification to features, advantages, or similar language does not imply that all of the features and advantages that may be realized with the present invention should be or are in any single embodiment of the invention. Rather, language referring to the features and advantages is understood to mean that a specific feature, advantage, or characteristic described in connection with an embodiment is included in at least one embodiment of the present invention. Thus, discussion of the features and advantages, and similar language, throughout the specification may, but do not necessarily, refer to the same embodiment.

(24) Furthermore, the described features, advantages, and characteristics of the invention may be combined in any suitable manner in one or more embodiments. One skilled in the relevant art will recognize that the invention can be practiced without one or more of the specific features or advantages of a particular embodiment. In other instances, additional features and advantages may be recognized in certain embodiments that may not be present in all embodiments of the invention.

(25) It is understood that the above described embodiments are only illustrative of the application of the principles of the present invention. The present invention may be embodied in other specific forms without departing from its spirit or essential characteristics. The described embodiment, including the best mode, is to be considered in all respects only as illustrative and not restrictive. The scope of the invention is, therefore, indicated by the appended claims, if any, in conjunction with the foregoing description.

(26) While the foregoing written description of the invention enables one of ordinary skill to make and use what is considered presently to be the best mode thereof, those of ordinary skill will understand and appreciate the existence of variations, combinations, and equivalents of the specific embodiment, method, and examples herein. The invention should therefore not be limited by the above described embodiment, method, and examples, but by all embodiments and methods within the scope and spirit of the invention.