US20080028699A1

US20080028699A1 - Foot tread and method of assembling same

Info

Publication number: US20080028699A1
Application number: US11/500,761
Authority: US
Inventors: Shu Wong Mak
Original assignee: Interwood International Ltd
Current assignee: Interwood International Ltd
Priority date: 2006-08-07
Filing date: 2006-08-07
Publication date: 2008-02-07

Abstract

A stair tread comprising a tread center manufactured from a plurality of elongated wood members. Each elongated wood member receives a lamination of higher quality wood which is glued to each elongated wood member. The elongated wood members are then edge glued to form a tread body. A nose member is attached to leading edge of the tread body and is manufactured from a single unbroken piece of high-quality wood. Additionally, a heel member manufactured from a single unbroken piece of higher quality wood is attached to the rear edge of the tread body. A side member manufactured from higher quality wood may be positioned adjacent each edge of the tread body as well.

Description

BACKGROUND OF THE INVENTION

1. Technical Field
This invention relates generally to stair treads. More particularly, the invention relates to engineered stair treads. Specifically, the invention relates to a stair tread which includes an inner core that is made from a plurality of horizontally oriented layers beneath an upper lamella and a solid wood portion adjacent the front and rear edge.
2. Background Information
Stair treads have been made from solid pieces of wood for many years. However, with the rising cost of wood, it has become customary to manufacture stair treads with an inner core of an inexpensive or inferior wood and to cover this core with a veneer of a more expensive and superior wood. Additionally, a solid front nosing is ordinarily provided on the stair tread as this portion of the stair tread is ordinarily exposed during normal use. This gives the stair tread the appearance of being manufactured entirely of the superior wood, but reduces the production cost of the stair tread and also offers a more stable tread against movement. This type of disclosure can be found in Belgrade U.S. Pat. No. 5,985,398 which provides a stair tread having an aesthetic appearance of a solid hard wood stair tread and presents a core layer made of lamellas of lower quality material glued laterally adjacent to each other. A nosing is provided along the forward portion of the stair tread. Weber, et al., U.S. Pat. No. 6,860,071 also provides for a stair tread having predetermined dimension which includes a bottom and top that are at least substantially parallel whereby a plurality of bottom lamellas are glued together along with a solid wood front nosing. Additionally, a top surface is provided which is thinner and made of a higher quality lamella.
While these devices are sufficient for the purpose for which they are intended, they include a number of drawbacks. Most notably, the lower quality wood can be seen from the rear portion of the stair tread. As homes with more open designs are developed, open stair cases whereby a rear portion of the stair tread is visible are becoming more common. Therefore, the need exists for a stair tread which has a higher quality wood adjacent the rear portion thereof. Further, while it is known to manufacture stair treads having a lower quality lamella covered by an upper quality thinner lamella in order to assure a more stable wood stair tread, the treads would be even more stable if assembled such that the upper lamella and lower lamella along longitudinal lengths of wood were first laminated and then edge glued one to another along the thickness of the tread. In this manner, a more stable stair tread will be provided.
There is therefore a need in the art for improved engineered stair tread that will not warp and bow over time and that is aesthetically appealing from the top, front and rear portions of the tread and which is stable and strong enough to support the cyclic use of the stair tread.

BRIEF SUMMARY OF THE INVENTION

The present invention provides a stair tread comprising a tread center having a top surface made from a lower quality wood having a leading edge and a rear edge; an elongated heel member made from a high-quality wood attached to the rear edge of the tread center; an elongated wooden nose member made from a higher quality wood attached to the leading edge of the tread center; and a lamination of higher quality wood extending over the top surface of the tread center.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

The preferred embodiments of the invention, illustrative of the best mode in which applicant has contemplated applying the principles, are set forth in the following description, are shown in the drawings and are particularly and distinctively pointed out and set forth in the appended claims.

FIG. 1 is a perspective view of the stair tread in accordance with the present invention;

FIG. 2 is a side elevational view of the stair tread shown in FIG. 1;

FIG. 3 is a sectional view taken along Line 5-5, FIG. 1;

FIG. 4 is an exploded assembly view of the stair tread shown in FIG. 1;

FIG. 5 is a partially exploded assembly view of the stair tread shown in FIG. 1;

FIG. 6 is a cutaway view of a second embodiment of the stair tread of the present invention;

FIG. 7A is a sectional view taken along Line 7A-7A, FIG. 6;

FIG. 7B is an alternative embodiment of a method of joining adjacent pieces of the stair tread shown in FIG. 6;

FIG. 7C is an alternative embodiment of a method of joining adjacent pieces of the stair tread shown in FIG. 6;

FIG. 7D is an alternative embodiment of a method of joining adjacent pieces of the stair tread shown in FIG. 6;

FIG. 7E is an alternative embodiment of a method of joining adjacent pieces of the stair tread shown in FIG. 6;

FIG. 8 is an exploded assembly view of a third embodiment of the stair tread of the present invention;

FIG. 9 is a partially assembled view of the stair tread of the present invention;

FIG. 10 is a side elevational view of the third embodiment of the stair tread of the present invention; and

FIG. 11 is a sectional view of the third embodiment of the stair tread of the present invention.

Similar numbers refer to similar parts throughout the drawings.

DETAILED DESCRIPTION OF THE INVENTION

The preferred embodiment of the wooded stair tread in accordance with the present invention illustrated in FIGS. 1-5 is generally identified by the reference numeral 1. In the embodiment of FIGS. 1-5, the wooden stair tread 1 comprises three elongated wooden members 10, 12 and 14 to define a tread center 16 having a leading edge 18 and a rear edge 20 parallel to and spaced apart from leading edge 18. Tread center 16 is also bounded by a pair of side edges 22.
In accordance with one of the specific features of the invention, tread center 16 is bounded on its leading edge by a solid wood nose member 24 having a rounded forward edge 25 to reduce chipping and to increase the aesthetic appeal of stair tread 1 and extending the entire length thereof. Additionally, a solid wood heel member 26 is mounted along rear edge 20 of tread center 16. Optionally, solid wood sides 28 may be mounted along side edges 22 of tread center 16 and may be butt-jointed against the edge of heel member 26. Side members 28 and nose member 24 may be attached by any convenient attachment means and are shown as a miter joint 30 in the attached drawings. As can be seen from FIG. 1, tread center 16 is surrounded on all four sides by solid wood members 24, 26 and 28.
Referring specifically to FIGS. 2 and 3, it can be seen that elongated wood members 10, 12 and 14 of tread center 16 have a first thickness. Each of these members is covered by an upper lamination 32. In accordance with one of the primary features of the invention, elongated wooden members 10, 12 and 14 are made of an inferior quality wood which would make tread center 16 relatively inexpensive to manufacture and define the majority of the thickness of stair tread 1. Upper lamination 32 is made of a higher quality wood, such as red oak, maple, mahogany, white oak or cherry, and is relatively thin in comparison to elongated wooden members 10, 12 and 14 to provide a nice appearance to tread center 16. Lamination 32 has a thickness that is less than 30% and more preferably 20% of the first thickness of elongated wooden members 10, 12 and 14, elongated wooden members 10, 12 and 14 of tread center 16 and lamination 32 define a tread body 33. In further accordance with one of the primary features of the invention, nose member 24 and heel member 26 are manufactured from high quality wood such as that which is used to manufacture upper lamination 32. Nose member 24 and heel member 26 have a height equal to the combined heights of elongated wooden members 10, 12 and 14 as well as laminations 32. In this manner, when laminations 32 are installed on elongated wooden members 10, 12 and 14 and heel members 26 and nose member 24 are installed on the leading edge 18 and rear edge 20 of tread center 16, a top surface 34, which is substantially level, is provided. Additionally, side members 28 would also be of a height equal to nose member 24 and heel member 26 to provide a continuous top surface 34 when side members 28 are installed. Elongated wooden members 10, 12 and 14 are attached to laminations 32 and to nose member 24, heel member 26 and side members 28 by way of a thickness of glue 36. The thickness of glue joints 36 are exaggerated in FIG. 3 and have a de minimis thickness when manufactured. As can be seen, elongated wooden members 10, 12 and 14, nose member 24 and heel member 26 are all attached with a traditional butt joint, as shown in FIGS. 2 and 3. However, a variety of other joints may be used to add strength to the composite stair tread 1.
Referring to FIGS. 6 and 7A, a hole 40 may be drilled into adjacent members of stair tread 1 and a dowel pin 42 may be positioned within the hole to provide added strength as well as to assist when aligning the various members of stair tread 1. Still further and referring specifically to FIG. 7B, a lap joint may be provided wherein a rabbit 44 is cut into the edge of each of the respective members 10, 12, 14, 24 and 26. Rabbit 44 of respective boards would be cut on opposite surfaces in order to allow them to matingly engage, as shown in FIG. 7B.
Referring to FIGS. 7C and 7D, a zigzag configuration may be provided in order to create more glue surface and to assist when aligning respective members 10, 12, 14, 24 and 26. A final version is to provide a tongue and groove arrangement, such as that shown in FIG. 7E.
In accordance with another element of the present invention and referring specifically to FIGS. 4 and 5, the method of manufacture is described. Elongated wooden members 10, 12 and 14 are first laminated by way of glue 36 each to a lamination 32 having a width similar to the associated elongated wooden member as is indicated by arrow A. Once each elongated wooden member 10, 12 and 14 has an associated lamination 32 attached thereto, they are laminated to each other by way of glue 36 and to heel member 26 and nose member 24, as is indicated by arrow B. In this manner, laminations A give the appearance that they each represent an individual solid piece of wood that would comprise both the elongated wooden member associated with each lamination 32. The glue lines between laminations 32 give the appearance that the wood is solid just as heel member 26 and nose member 24 are solid. In furniture manufacture as well as in fine carpentry, generally large expansives of wood are not utilized for things such as stair tread and the glue lines would give the appearance that it was a crafted member, rather than a manufactured member using lower quality tread center 16 surrounded by higher quality laminations 32, nose member 24 and heel member 26.
It can be seen that by providing a solid heel member 26 as well as a solid nose member 24, the stair tread will remain extremely stable given that it has solid wood adjacent both longitudinal edge surfaces of tread center 16. If stair tread 1 is utilized on an open staircase, having a solid heel member 26 will provide a more aesthetically appealing stair tread when viewed from the bottom or rear of the open staircase.
Referring next to the second embodiment of the invention shown specifically in FIGS. 8-11 and referenced by the numeral 50, it can be seen that stair tread 50 is similar to stair tread 1 in every respect, except that a bottom lamination 52 is provided by way of glue joints 36 to elongated wooden members 10, 12 and 14. Referring to the method of manufacture and specifically to FIG. 8, it can be seen that each elongated member of stair tread 50 is reduced in thickness with respect to the elongated members shown with respect to stair tread to provide sufficient room to accept bottom laminations 52. Top laminations 32 and bottom laminations 52 are each applied to an individual elongated wooden member 10, 12 and 14 by way of glue 36. Referring to FIG. 9, each assembled laminated elongated wooden member 10 is glued one to another and a solid wood heel section 26 and nose section 24 are applied to the edge portions of tread center 16. In this manner, a stair tread that gives the appearance of high quality wood from both the top and bottom may be manufactured for use on open stairways and the like.
While the preferred embodiment of the stair tread of the present invention is being disclosed as made entirely from wood from the same species, with the outer region comprising higher grades of that wood and the inner core comprising lower grades of the same species, it will be understood by those skilled in the art that the entire core may alternatively be manufactured from different, less expensive, lower grade lumbers, including manufactured wood products, such as chipped board or particle board or medium density fiber board. Additionally, the inner core may be manufactured from less expensive natural wood varieties, such as pine or poplar.
In the foregoing description, certain terms have been used for brevity, clearness, and understanding. No unnecessary limitations are to be implied therefrom beyond the requirement of the prior art because such terms are used for descriptive purposes and are intended to be broadly construed.
Moreover, the description and illustration of the invention is an example and the invention is not limited to the exact details shown or described.

Claims

1. A stair tread comprising;

a tread center having a top surface made from a lower quality wood having a leading edge and a rear edge;

an elongated heel member made from a high-quality wood attached to the rear edge of the tread center;

an elongated wooden nose member made from a higher quality wood attached to the leading edge of the tread center; and

a lamination of higher quality wood extending over the top surface of the tread center.

2. The stair tread of claim 1 wherein the nose member and heel member each have an edge and an upper surface; and in which the lamination abuts the edge adjacent the upper surface.

3. The stair tread of claim 2 in which the tread center has a first thickness and the lamination has a second thickness and in which the second thickness is less than 30% of the first thickness.

4. The tread center of claim 3 in which the nose member and the heel member have a third thickness and in which the third thickness equals the sum of the first and second thicknesses.

5. The stair tread of claim 2 in which the nose member, heel member and tread member define a pair of edges and in which a solid wood side is attached to at least one of the edges.

6. The stair tread of claim 5 in which a solid wood side is attached to both of the side edges.

7. The stair tread of claim 2 in which the lamination, heel member and nose member are manufactured of the same material.

8. The stair tread of claim 2 in which the heel member is a solid unbroken piece of higher quality wood.

9. The stair tread of claim 8 in which the tread center further comprises a plurality of elongated wood members, each having a width and an edge and in which the edges adjacent elongated wood members are attached.

10. The stair tread of claim 9 in which each lamination has a width equal to the width of the associated elongated wooden member of the tread center.

11. The stair tread of claim 10 in which the tread center is made from at least three elongated wooden members.

12. The stair tread of claim 11 in which the heel member has a width equal to at least 40% of the width of the smallest width elongated wooden member.

13. The stair tread of claim 12 in which each elongated wooden member has an equal width and in which the heel member has a width equal to said equal width.

14. The stair tread as defined in claim 11 in which the elongated wood members and laminations are joined to form a tread body and in which the nose member and heel members are joined to the tread body.

15. The stair tread of claim 2 in which the elongated wooden members are attached to one another and in which each of the nose member and heel member are attached to one another by a joint consisting of one from the group of butt joint, lap joint, dowel pin joint, zigzag joint and tongue and groove joint.

16. The stair tread of claim 15 in which all joint in the stair tread are the same.

17. The stair tread of claim 2 further comprising a bottom lamination of higher quality wood and in which the stair tread has a bottom surface and in which the bottom lamination of higher quality wood is secured to the bottom surface of the stair tread.