Patent Application
20230313535
This application claims the benefit of priority of U.S. non-provisional application Ser. No. 29/788,516, filed Jun. 15, 2021, the contents of which are herein incorporated by reference.
The present invention relates to stair construction or fabrication and, more particularly, a stair stringer system embodying metal stair fixtures, and a method of making the same by using a framing square to install the step-shaped components.
There is an absence of solutions to the tedious task of cutting 2×12s into sawtooth shapes to build stairs. The procedure is risky and wasteful and time consuming for skilled craftsmen.
When fabricating stairs, the treads need to be level and the risers need to be equal in height. Building codes typically require equal risers with a difference not to exceed ⅜″, and a comfort formula, Riser+Tread=17½″+/−, can assist the builder in selecting those two dimensions. In the making of stairs, notably, the most important ability is adjustability because the height of stairs vary. And stock stringers, however, do not necessarily meet this criterion when confronted by the varying heights of actual job site conditions. Again, current stock stringers are fixed and lack adjustment and so they typically fail to meet the relevant building code.
Current stair fabrication solutions have a special track made for the bottom step, where two ruler tabs are used to locate the bracket on the 2× stringer member. The typical stair in an eight-foot ceiling requires three (3) stringers and thus at least seventy-eight different tab readings to perform and match to properly install the stairs. Understandably, parallax error is a factor.
Moreover, a tread may intentionally project an inch or so over the riser to form a nosing, a cantilever safety feature. The riser may be inclined to support the nosing.
As can be seen, there is a need for a stair stringer system embodying a plurality of stair fixtures, as well as a method of stair fabrication using the plurality of stair fixtures and a framing square, whereby lower-skilled craftsman (DIYer) can take a box of the stair fixtures, and fabricate stringers using 2×4s and following instructions, thereby gaining an advantage over cutting stringers from large dimension lumber.
The present invention provides a stair stringer system that facilitates safety—i.e., building a stair with equal height risers that meets building typical code requirements—and aesthetics in making a stair without nail blemishes on the treads and risers.
The present invention embodies an inclined riser model that produces a modernist stair result that is unique and features a functional safety nosing.
The present invention eliminates the need for large-dimensional lumber and minimizes blocking at walls where, through the advantages of the present invention, 2×4s are replaced with 1×4s, saving 50% on blocking material (wherein blocking the stringer allows for finish material and a skirt board to pass by the stringer and protect the wall).
The present invention significantly reduces waste since cutting conventional wood stringers involves discarding ⅓ of the blank when cutting off the small triangle shapes that seemingly have no other use. Large dimension lumber (e.g., 2×10s and 2×12s) is expensive, and the waste is costly and negatively impacts the environment. Typically, the large dimension lumber has to be at least twelve feet in length for stair stringers and they need to be straight and free of major knots and cupping and splits; these requirements make this wood expensive and sometimes difficult to find because most houses are built with no large dimension lumber (except maybe door lintels over double or sliding glass doors and garage doors); rather “Microlam”, a beam made with laminates of thin wood, has replaced much of the large dimension lumber as it is stronger and uses smaller trees. Also, attaching metal fixtures to 2×4s or 2×6s is light duty compared to the extensive cutting required in turning heavy 2×12s into sawtooth shaped stringers.
The present invention embodies metal stair brackets providing an abundance of holes spaced one inch apart, making the underlying system adaptable.
The present invention embodies a one-tool solution for building the stairs: a framing square. The framing square is used, in conventional methods, to layout a stringer for cutting and stair gauges placed on the square project the riser and tread dimensions onto the 2× material. In the present invention, the framing square lays out the 2× pattern in preparing for the application of metal stair fixtures. Using that pattern to mark other 2×s ensures alignment between steps in stringers of the same stair. The fixtures are identical; therefore, the framing square installer consistently places them precisely with the same exposure, so that an onsite operation reproduces consistent and repeatable results.
The present invention embodies a bilateral (left or right functioning) system with uniquely shaped metal stair brackets lacking tab indices indexes or clusters of holes and are installed by way of a framing square installer. The metal stair brackets are adjustable and provide a continuous strip of unused holes to key adhesive to metal fixture.
Tab indexes require an accurate increment selection two times on each fixture (assume an 8′ ceiling height, that's 13 risers×3 stringers×2 tabs=78 indexes to read and set correctly) Index tab reading on that level is exhaustive work. Parallax error is a factor on each selection. Using the framing square, as embodied in the present invention, as an installation tool relies on the stair gauges for a positive contact with the 2× face on each fixture placement. This seems to be less error prone and a more reliable method by reducing the selection process significantly. The bottom line: framing square installation produces stair stringers of greater precision by a more accurate and reliable placement of identical metal fixtures.
The design of the fixture and instructional method are intended to meet and exceed conventional standards in fabricating precision stair components. The metal fixtures are factory reproduced to be identical in dimension and easily compete with a site made saw cut step configuration. Using a framing square to layout the stringer pattern, and marking the other 2×s of the same stair, reflects conventional methods in duplicating a cut stringer for a pattern. The method of instruction is to repeat exact step locations on the stringer. And rely on the identical metal fixtures, placed by the same framing square, controlled by the same stair gauge exposure, to complete a precise reproduction of the pattern stringer.
Another aspect of the present invention is that the system facilitates access to the underside of the stairs, which is desirable. For instance, the treads and risers may be checked for fit, removed and adhesive applied to the side of the fixture not used for screws, which are replaced by a worker on the upper side of the stair.
Another worker below the stairs may attach the treads and risers with screws (where a panel is attached to finish the stairs). Providing more space under the stairs by furring down the bottom panel is an alternative method; this allows one individual to finish the riser and tread assembly.
The goal in fabricating stair stringers is reproducing matching components used in the same stair. The typical interior stair has three stringers and one of those should have metal fixtures fastened to the opposite side to facilitate fastening risers and treads. The metal fixtures are identical and placing them on the 2× with a framing square facilitates identical settings. To achieve matching spacings on the 2×s a layout pattern is used to mark the edges of other 2×s for the same stair. Cutting the top and bottom of the pattern is also projected onto the other 2×s. This procedure results in superior components that match and align compared to sawing them from wide lumber stock.
The metal stair fixture embodied in the present invention can change the way stairs are built in most single and multifamily houses and many commercial and industrial buildings, the majority of structures. Being simple and obvious in function is necessary because the industry isn't known for employing highly educated, sophisticated personnel.
The bottom fixture/s is/are unique because the transition step, unlike others, has a stringer/riser that intersects the floor or landing. This issue requires special fixture adapting and angle cutting the 2× to produce equal risers on the stairs. The bottom fixture is bent to form an anchor bracket for the stringer.
The stair brackets and overall system of the present invention is bilateral and does not require a left and right version. A single form fits left and right and is configured to the bottom of the stair stringer.
The present invention contemplates an inclined riser and a vertical riser model. The inclined riser and a vertical riser model provides a shape that has a fixed flange which means that any riser over 6″ in height will not be flat against the flange at the bottom but spaced slightly ( 3/16″ max.) off the flange surface. To compensate for this a cut in the flange base permits the screw connection to break away and form a flex tab that bridges the gap to secure the riser board bottom. A screw secures the flange-riser contact at the top and adhesive compensates for gaps that exist. A nosing projection of 1⅛ is fixed by the metal shape component and that remains unchanged as the riser height varies. The flex tab concept permits the inclined riser shape to configure to various riser heights while retaining the framing square install.
A dual row of holes provides a key for a bead of adhesive to the fixture and attach a row of screws, hidden from view.
The shape of the stair bracket of the present invention is unique. A special bottom piece is not required as the fixture is adapted to form an anchor bracket for the stringer. Because in the typical stair there are three stringers and ⅓ of the metal fixtures need to be attached on the side opposite the other ⅔s. This facilitates attaching “hidden” screws to the treads and risers. Mounting the fixtures to the same side of all three stringers would make attachment of the risers and treads difficult and eliminate normal wall finish/skirt board clearances.
The present invention embodies a repetition of the appendages forming a rhythmic sequence not unlike giant saw teeth.
The comfort and safety level of a stair is largely a result of the tread and riser dimensions, and the stringer defines this quality. The formula: riser+tread=17½″+/− can assist the builder in selecting those two dimensions. The following advantages are informative.
First, metal fixtures afford adjustability whereby a user can produce a stair with equal height risers which is a safety issue and meets building code, which stresses safety, and the population needs a stair without surprises that can lead to falls. The standard method is to custom cut large dimension lumber (2×10s or 2×12s) into sawtooth shaped members and deliver risers that are equal in height. This is the task of a specialist and not the duty of the average framing employee, who requires an understanding of code riser height limitations and corresponding tread dimensions to arrive at a comfortable and safe stair. To say that stairs vary is an understatement.
The second advantage of using a metal stair step fixture is labor reduction. Attaching metal fixtures to 2×4s or 2×6s is light duty compared to the extensive cutting required in turning heavy 2×12s into sawtooth shaped stringers. Using metal stair fixtures requires less construction experience so there is a labor savings in the professional industry. Because of the prefabricated nature of a metal stair step fixture, the practice of installing stairs is available to non-professionals (i.e., Do It Yourselfers, DlYs).
Thirdly, metal stair step fixtures provide a stair with hidden fasteners on the risers and treads which are fastened by screws from the back or under side of the stair.
A fourth advantage to metal stair step fixtures is that they offer both a traditional vertical riser and an inclined riser with a nosing model, wherein inclined risers result in a modernist or waterfall stair as well as a safety feature.
Fifth, the metal stair step fixtures enable replacing the 2×10s and 2×12s with 2×4s and 2×6s, resulting in a material savings of 56% on average, and a monetary savings greater due to replacing premium price lumber with lower price small dimension pieces (as well as a 50% savings on blocking at walls).
A sixth advantage is that metal stair brackets are bilateral and function on the left or right side of the 2× members, thereby eliminating the dilemma of needing fixtures to complete a job and having left hand but needing right hand.
Seven: unused screw holes act to key adhesive to the metal fixture. Separate rows of holes provide both a row for screws and one for a continuous strip of adhesive.
An eighth reason is that installing a metal fixture does not damage it and it may be removed and adjusted for errors or reused in a deck stair replacement, while standard practice lacks adjustment and has little chance of reuse.
A ninth advantage is that metal stair fixtures are galvanized and adapted for interior and exterior use.
A tenth reason is that while conventional stringers are fragile and triangle step pieces often break off, metal stair fixtures are resilient and are resistant to damage (i.e., metal fixtures make an excellent repair method).
Temporary treads are typically installed to prevent damage to finish materials; metal stair fixtures readily adapt to this concept.
Stocking the fixtures, available in cartons of 12, along with 2×4s & 2×6s, is easier than dealing with 2×10s & 2×12s @ 12 and 14 feet. It also takes a big tree to produce a 2×10 or 2×12. Cupping and cracks are common in large dimension lumber. Studs, plates, joists, and rafters use 2×4s and 2×6s and both are common on construction sites.
Another reason is safety: adding screws to a metal stair fixture is much safer than using a circular saw to cut a 2×12×14′ into a sawtooth shape. Furthermore, meeting the building code “equal height risers” is a safety issue, which the metal stair fixture enables. And offering an inclined riser model is mandating a safety nosing. A circular saw probably accounts for more accidents than any other tool on the jobsite. The blade guard is often held up by a wood wedge because it tends to jam or guide the saw in a direction other than desired on angle cuts. Full blade exposure is needed to reduce overcut at vertices which can reduce stringer depth.
Yet another reason is waste reduction: cutting large boards into stringers produces ⅓ waste by creating a pile of sawdust and another pile of triangle shapes of useless wood debris. These wide boards are expensive and the result of harvesting large trees.
Metal stair fixtures are adjustable between 6″ and 8″ in riser height and a minimum of 9.5″ in tread.
In one aspect of the present invention, a bilateral bracket for steps to be fixed on a stringer having a number of steps and risers, the bilateral bracket includes the following: a generally flat body defining a framing edge having a riser edge and a tread edge; the riser edge having a riser flange perpendicularly extending therefrom in a first direction; the tread edge having a tread flange perpendicularly extending therefrom in the first direction, wherein the tread extends between a distal end and a proximal end; the riser and tread edges defining an acute angle relative to each other, wherein the flat body does not project beyond a profile defined between two lines orthogonally drawn from each of the distal and proximal ends; and a stringer edge along the body, opposite the framing edge, wherein the stringer edge has an array of holes for selectively attaching to either side of the stringer in one of a plurality of orientations so as to adjust an elevation of the tread edge relative to said stringer, wherein the array of holes comprises two rows of holes, wherein adjacent holes of each row of holes are approximately one inch apart, and wherein the row of the two rows of holes that is closer to the tread flange is along a line orthogonal relative to a distal end of the tread flange so that when folded along said row a bent flange is form substantially parallel to the tread flange, and wherein the bent flange circumscribes the other row of the two rows of holes, whereby the bent flange provides an anchor for a bottom step.
In another aspect of the present invention, a method of installing the bilateral bracket includes the following: method of installing the bilateral bracket of claim 1, the method including the following: affixing a framing square to a 2×; defining an orientation of the bilateral bracket relative to the 2× as a function of a riser value and a tread value for the number of steps and risers; and clamping the bilateral bracket to the framing square prior to attaching the stringer edge to the 2×, wherein a majority of the tread flange engages a first leg of the framing square during attachment of the bilateral bracket to the stringer, wherein a distal end of the riser flange engages a second leg of the framing square during attachment of the bilateral bracket to the stringer; and further providing marking along edges of the first and second legs of the framing square along a face of the 2×.
These and other features, aspects and advantages of the present invention will become better understood with reference to the following drawings, description and claims.
The following detailed description is of the best currently contemplated modes of carrying out exemplary embodiments of the invention. The description is not to be taken in a limiting sense but is made merely for the purpose of illustrating the general principles of the invention, since the scope of the invention is best defined by the appended claims.
Referring now to
The shape components or stair bracket attaches in multiples to a 2×4 or 2×6 to form a stair stringer. This metal-wood fabrication is intended to replace the conventional method of butchered 2×12 stringers. A battery powered screwdriver replaces the circular saw to attach identical shapes that are the result of CNC (computerized numerical control) technology.
There are two components of the stair bracket: a typical vertical riser and an inclined riser with a nosing are featured. One simple component works on the left or right side and configures to the unique bottom step situation. The bottom step is unique because it has the only riser that is reduced to account for the tread thickness, enabling a metal floor connector that anchors each stringer.
At the heart of the metal shape component system is the framing square being used as an installation tool. Placing shapes accurately on a 2× requires using the framing square. At least one clamp is required and the square needs stair gauges.
Stair construction requires making several identical stringers that need to align in supporting the treads and risers. This requirement of precision is met by metal shapes that are formed by the close tolerances of a manufactured product which easily exceeds the result on-site built stringers.
Now that the shapes match, they must also be placed on the 2×s in a uniform and equally spaced sequence. The objective is to be aligned with the corresponding shapes on the adjacent stringers. The initial procedure of a pattern layout and edge marking ensures that this happens.
Basically, metal shape use can exceed conventional methods in having more identical step dimensions and form and they can match the stringer arrangement by mimicking the pattern technique. Both systems use the same technique to ensure that each step aligns with its respective mates of the same step. And the framing square is involved in both techniques.
The step-shaped metal components are designed to be clamped onto a framing square and the stair gauge setting determines placement on a 2× in a repetitive and precise fashion. Setting the stair gauges one time on the square for this procedure is better than reading two scales on a single shape installation.
On the inclined riser version, a cut exists near the bottom of the flange on the inclined riser version of the shape component. The intent is to allow the bottom flange to break away in the likely event that a riser greater than 6″ is selected. In selecting a riser greater than 6″ the board will not fit against the metal flange and by allowing the flange to break away a flexible tab is formed to secure the bottom of the riser. If an 8″ riser is selected a space of about 3/16″ exists between the flange and the riser board and this is the maximum situation. A hole is placed very near the flange end and it is expected that the second hole would be used in a 6″ riser to avoid splitting.
The screws placed near the top of the flange have a reduced space between the flange and the board, relative to the bottom, and adhesive thickness compensates to close this differential. This issue is the result of making a shape that is adjustable where the nosing remains 1⅛″ and the riser height varies, which is to say the angle of inclination varies to meet the ideal nosing dimension.
The shapes are attached to a 2× in multiples and a single form works for both right and left and bottom step applications. Building codes require that all risers in a stair be equal in height and shapes adjust to any riser between 6″ and 8″. There is a shape for standard vertical risers and a shape for inclined risers that includes a nosing. The galvanized sheet metal material is intended for interior and exterior use. Screws and supplemental adhesives secure the metal flange to the treads and risers and fasteners are hidden and applied from the rear or underside of the stair. A continuous separate line of holes 18 (in some embodiments, the lines are spaced apart by approximately one inch on center) which enables keying the adhesive to the flange.
Using a framing square to place the shapes is more accurate than ruler tabs of tiny increments or hole clusters that other metal shapes feature. Stair construction requires precision stringers that align when placed side by side. Using shapes that are plasma cut and CNC manufactured easily exceed the tolerances of an on-site cut 2×12 stringer. Mimicking the pattern layout on the component 2×s, just as a conventional stair builder uses a cut stringer as a pattern to mark other 2×s intended for the same stair, ensures that the component stringers align.
The riser height and tread thickness selected determines the bottom shape configuration and it is bent to form a bracket to anchor the stringer to the floor. This adaptation to a problematic issue, caused by dissimilar riser heights combined with various tread thicknesses, permits a single shape form to meet the requirements of almost all wood-based stairs. Adjusting to common riser and tread dimensions, providing equal riser heights, and bending to configure an anchor bracket for each stringer is characteristic of the metal shape function.
Metal shapes easily adjust to any riser between 6″ and 8″ and corresponding tread selections. The shapes easily work in left or right-side applications. However, to use that same shape in the bottom step application it must be configured or bent to create a bracket that serves to anchor the stringer to the floor.
Replacing the traditional multifaceted wood stringer with a smooth member having metal appendages reduces combustible material in a critical circulation area in the event of a fire. This aspect is additional safety to a system that has eliminated the cutting of stringers. To wit, the extensive cutting of large dimension lumber into giant sawtooth forms increases the ignition potential compared to a smooth or beam-like member.
Sheet metal is used to form a step shaped fixture that functions in right or left mountings. Both are necessary to facilitate hidden fasteners (screws) being applied from the back or under side of stair. Adhesive is also applied to the row of screws not used for mechanical fastening. The row of holes key the glue to the fixture for a secure bond. Two rows exist on each riser and tread flange to allow this to take place. The metal fixtures are adjustable and may be removed to correct errors. Adjustable is necessary because a safe stair has equal riser heights (a code requirement).
Each stair bracket 10 is bilateral and a single shape functions to work in left and right applications. There are no scale tabs and a framing square 20 is used to install the shapes. This is a more precise method and reduces the chance of error such as misreading a scale of which there are many in the typical stair.
The stair bracket 10 is bent and configured to the unique bottom steps by forming an anchor bracket, as shown in
The framing square 20 is common to construction sites and a stair craftsman uses one to layout a stair stringer 50 which becomes a pattern for marking other members intended for the same stair. Small stair gauges clamp to the square and reflect riser and tread selections. This same setup is used to layout and install metal shapes. Framing square 20 is used in a preliminary procedure of laying out a pattern and using it to mark other members for the same stair.
A method of using the invention may include the following. In building a stair, the risers and treads should be identical, and the stringers should match. Marking the 2×s member 60, as illustrated in
Referring to
Referring to
The installation tool 20, again, repeatedly determines the exact riser and tread exposure and the marks locate the steps to match other stringers having the same marks. The square setting that is the origin of the marks is now placing a connector within the marks. The bottom of the stringer requires special attention. Attach the bottom connector with two fasteners and mark the 2× and the connector for cutting. Check that trimming the 2× will not delete the screw holes, then remove the two fasteners.
Trim and form the connector to create a bracket to act as a floor anchor (exterior connector protrusions may be embedded in concrete or formed to anchor to a landing). Install the bottom connector using previously made holes.
Mark and trim the top of the stringer. Use this stringer as a pattern to trim the top and bottom of others on the same stair.
As a precaution, choose a 2× to have connectors mounted on the opposite side and mark “XX's” on the side you wish to avoid. The connectors are mounted on the inside face of an end-of-tread stringer. This facilitates riser and tread attachment and reduces the thickness of blocking at walls. (The stringer is spaced, blocked, away from the wall studs to allow finish material and a skirt board to go behind the sawtooth stair shape, and protect the finish wall surface from foot traffic and cleaning tool damage). Now finish the remaining stringers in a similar fashion.
Temporary treads may be used to avoid damage to the finished material. Use adhesive and screws to fasten the finished material to the connectors. Apply a bead of adhesive over the line of holes not intended for screws on each connector.
The metal connectors are without markings that would locate their placement and depend on the square installation tool to locate their placement. This feature ensures precision placement each time. The installer is not reading a scale with numbers or selecting a hole from a cluster of holes.
Metal fixtures are noncombustible material replacing combustible material in an area used to escape a burning building.
A step shaped metal appendage, adjustable and calibration impaired, concealed fastening and bilateral, uses the lowly framing square as an installation tool to add speed, safety and fire resistance to fabricating stair stringers.
Sporting an inclined riser model, with a mandated safety nosing, and a traditional vertical riser version, the galvanized steel product can create a modernist wood interior stair and an exterior deck stair. Both have concealed fasteners and employ screws and adhesive in assembly and eliminate the need for large dimension lumber for building stair stringers. Both treads and risers use hidden fasteners for a blemish free furniture grade finish. Mounting holes at 1″ spacing invite prefinished flooring to be used and the wood varieties are numerous and exotic.
As used in this application, the term “about” or “approximately” refers to a range of values within plus or minus 10% of the specified number. And the term “substantially” refers to up to 80% or more of an entirety. Recitation of ranges of values herein are not intended to be limiting, referring instead individually to any and all values falling within the range, unless otherwise indicated, and each separate value within such a range is incorporated into the specification as if it were individually recited herein.
For purposes of this disclosure, the term “aligned” means parallel, substantially parallel, or forming an angle of less than 35.0 degrees. For purposes of this disclosure, the term “transverse” means perpendicular, substantially perpendicular, or forming an angle between 55.0 and 125.0 degrees. Also, for purposes of this disclosure, the term “length” means the longest dimension of an object. Also, for purposes of this disclosure, the term “width” means the dimension of an object from side to side. For the purposes of this disclosure, the term “above” generally means superjacent, substantially superjacent, or higher than another object although not directly overlying the object. Further, for purposes of this disclosure, the term “mechanical communication” generally refers to components being in direct physical contact with each other or being in indirect physical contact with each other where movement of one component affect the position of the other.
The use of any and all examples, or exemplary language (“e.g.,” “such as,” or the like) provided herein, is intended merely to better illuminate the embodiments and does not pose a limitation on the scope of the embodiments or the claims. No language in the specification should be construed as indicating any unclaimed element as essential to the practice of the disclosed embodiments.
In the following description, it is understood that terms such as “first,” “second,” “top,” “bottom,” “up,” “down,” and the like, are words of convenience and are not to be construed as limiting terms unless specifically stated to the contrary.
It should be understood, of course, that the foregoing relates to exemplary embodiments of the invention and that modifications may be made without departing from the spirit and scope of the invention as set forth in the following claims.
| Number | Date | Country | |
|---|---|---|---|
| Parent | 29788516 | Jun 2021 | US |
| Child | 18331306 | US |
