CA1315068C - Staircase stringer assembly - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE
The present invention relates to a staircase stringer assembly having only three main structural parts which may all be formed from extruded metal stock. The components of the assembly include a stringer member having an integral outwardly open channel which extends longitudinally the entire length thereof. The assembly according to the present invention also comprises a riser member having flanges for slidable engagement with the channel of the stringer member. A run member completes the assembly. The run member is adapted to cooperatively engage with the riser member and provides a substantially planar and horizontal surface for supporting a single stair tread or step placed thereon. The use of only three main structural parts in the staircase stringer assembly of the present invention results in lower manufacturing costs for a particular installation when compared to known staircase constructions. Furthermore, a staircase installation using the staircase stringer assembly according to the invention may be shipped conveniently and inexpensively to the building site in disassembled form rather than as bulky sub-assemblies, The present invention is also easily adaptable to different staircase designs and configurations.

Description

131~068 , ~TAIRCASE STRINGER ASSEMBLY
The present invention relates generally to staircase constructions and more specifically to a staircase stringer assembly which may be formed of extruded metal parts for easy interconnection and adaptability to various configurations.
Typically, metal staircases for indoor or outdoor use are prefabricated in metalwork production shops and are shipped as bulky sub-assemblies to building work sites.
Upon assembly of such traditional staircases, a considerable amount of welding may be required in order to join the relevant sub-assemblies which necessitates that such staircases be painted or otherwise finished following the assembly and installation thereof. It may also be appreciated that many of the known staircase designs involve a considerable number of constituent components which are poorly adaptable to different staircase configurations.
The present invention provides a staircase stringer assembly having only three main structural parts which may all formed from extruded metal stock, preferably of aluminum alloy or the like. The components of the assembly include a stringer member having an integral outwardly open channel which extends longitudinally the entire length thereof. The assembly according to the present invention also comprises a riser member having flanges for slidable engagement with the channel of the stringer member. A run member completes the assembly. The run member is adapted to cooperatively engage with the riser plate and provides a substantially planar and horizontal surface for supporting a single stair tread or step placed thereon.

~.. . ... i,,, .. . , .. ,, , , -:- , 2 131~068 The use of only three main structural parts in the staircase stringer assembly of the present invention results in lower manufacturing costs for a particular installation when compared to known staircase constructions. Furthermore, it may be appreciated that a staircase installation using the staircase stringer assembly according to the invention may be shipped conveniently and inexpensively to the building site in disassembled form rather than as bulky sub-assemblies. The present invention is also easily adaptable to different staircase designs and constructions.
The structural parts of the present invention are readily suited for receiving a surface finish following the manufacturing thereof. These structural parts need not be welded together, but may be joined with fasteners such as screws or preferably rivets. When so fastened without having recourse to welding, the surface finished components of the staircase stringer assembly according to the present invention do not require an additional surface treatment such as painting following the installation thereof.
According to one broad aspect of the present invention, there is provided a staircase stringer assembly for supporting a plurality of stair treads, said staircase stringer assembly being formed from extruded metal components and comprising: at least two side stringer members angularly disposed in a laterally spaced apart and substantially parallel relationship, said side stringer members each respectively providing an outwardly open channel extending longitudinally the entire length thereof;
a plurality of stringer riser members adapted for slidable interconnection with said open channels of said stringer .

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3- 131~68 members and identically disposed therein at predetermined spaced apart intervals; a plurality of corresponding run members, said run members being adapted to cooperatively engage with said rise plates and providing a substantially flat surface for supporting said stair treads.
According to another broad aspect of the present invention, there is provided a staircase stringer assembly comprising a stringer member, a plurality of riser members and a plurality of run members, said stringer member comprising an elongated hollow member having a flat top surface and a first channel beneath said top surface, said top surface having a slot communicating with said channel, each said riser member comprising a flat plate having a top edge and a bottom edge, said top edge comprising a support for a run member and said bottom edge having transversely extending flanges adapted to be received in said channel, said run member comprising a flat plate having two depending ribs adapted to be disposed on either side of the riser member, said riser member being secured to said stringer and said run member being secured to said riser member.
In its preferred embodiment, the stringer member of the stairoase stringer assembly is of a hollow rectangular cross-sectional configuration, the outwardly open channel thereof being disposed adjacent the entire upper surface thereof The riser member consists of a plate having an inverted T-shape with lower flanges for slidable engagement with the open channel of the stringer member. Once so engaged, the riser plate is adapted to provide a leading edge which is substantially horizontal when the stringer is properly positioned in forming a staircase. The run member has a generally T-shaped cross-sectional configuration with --` 1315~68 two parallel and downwardly facing short ribs for receiving therebetween the leading edge of the riser plate described above.
Each of the components of the present staircase stringer assembly is typically extruded in twenty-foot lengths which may receive a surface finish, for instance, in the form of baked enamel or an anodized coating. The extruded and surface finished stringer member stock is then easily cut to size to suit a particular installation.
The stock riser plate extrusion is initially in the form of a thin plate having a T-shaped flange portion which extends the entire extruded length thereof. The riser plate components are first sectioned transversely of the direction of extrusion and are then cut obliquely to that direction at an appropriate angle to suit the angle of inclination of the stringer members and so as to form a substantially horizontal leading or upper edge over which may be received the rib portion of a correspondingly sized run member.
Stair or tread steps suitable for use with the present invention may be composed of various hardwoods, aluminum alloys, marble and other quarried stone or composite materials such as those known under the trade-; mark FIBREGLAS.
The three main components of the staircase stringer assembly according to the present invention may be permanently interconnected by way of fasteners such as metal screws or preferably rivets. To aid in the placement of su¢h fasteners, the outside surfaces of the components may be provided with integrally extruded guide grooves whiah run the entire longitudinal length of the component parts. !Moreover, in order to facilitate the placement of ;~:

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' ~ - -, the riser plates at the desired intervals along the length of a stringer member, spacing means such as a suitably-shaped spacing rod of a predetermined length may be inserted into the open channel of the side stringer members so as to position each riser plate accurately along the length of the side stringer members prior to their permanent attachment thereto. For attachment of each stair tread to the horizontal surface of the run members, the latter may be provided with holes for receiving screws or other suitable fastening means, well known to those skilled in this art, for attachment to the underside of the stair treads.
The inside surfaces of each side stringer member are preferably provided with four integral paired flutes running the entire longitudinal length thereof and forming arcuate slots having a generally C-shaped cross-section.
These paired flutes are rectilinearly spaced apart and may be tapped for receiving screws which would permit the terminal ends of the side stringer members to be attached to variou~ end pieces or support surfaces. In this manner, an end piece such as a plate may be attached to the bottom ends of a pair of side stringer members, which would in turn be secured to a concrete footing by suitable attachment means well known to those skilled in this art.
At the upper terminal ends of a pair of side stringer members, the end plate may be vertically disposed for like attachment to the header of a staircase landing or that of a balcony. Alternatively, the four paired flutes within the side stringer members may be used without an end plate, for instanoe, when such side stringers are horizontally disposed as beams or joists for supporting a landing.

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1315~68 Projecting ridges extend inwardly from each of the four arcuate slots and are adapted to slidably receive a reinforcing member having a generally rectangular hollow cross-sectional configuration. The reinforcing member may consist, for instance, of galvanized metal stock. The reinforcing member is recommended as a means of adding structural strength and rigidity to the stringer members when the staircase stringer assembly according to the present invention is intended for a very long staircase configuration or for installations where heavy loading or use is expected.
The stringer members of the present invention also preferably provide an integrally extruded lower channel running the entire longitudinal lengths thereof. This lower channel permits paired, straight or angled flat plate members to be inserted in the respective outwardly open channel and lower channel so that two sections of stringer members may be joined together in a desired configùration, either straight or angled.
In drawings which illu~trate embodiments of the invention:
FIG 1 is an isometric partially exploded and sectional view of one embodiment of the staircase stringer assembly according to the present invention showing a stringer member, a riser member, a run member and part of a stair tread;
FIG 2 is a cross sectional view of the stringer member depicted in FIC 1, and further showing a spacing rod and reinforcing member in dotted lines;
FIG 3, located on the second sheet of draw~ngs, is a plan view of a typical staircase configaration using the :
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staircase stringer assembly according to the present invention;
FIG 4 is a partial cross sectional view of the staircase configuration depicted in FIG 3, viewed along line IV-IV thereof;
FIG 5, shown on the same sheet of drawings as FIGS 1 and 2, is another partial cross sectional view of the staircase configuration depicted in FIG 3, taken along line V-V thereof;
FIG 6, located on the second sheet of drawings, is yet another partial cross sectional view of the staircase configuration depicted in FIG 3, taken along line VI-VI
thereof.
Referring now to the drawings, FIG 1 depicts the interconnection of the component parts of the staircase stringer assembly for supporting stair treads such as stair tread 4. The assembly comprises a stringer member 1 which i8 of generalIy rectangular hollow cross-sectional configuration. Stringer member 1 contains, adjacent its ,~ 20 entire top longitudinal length, a channel 10 communicating ~: wlth a slot 10a for slidably receiving the base of a riser plate 2. The riser plate 2 has transversely extending lower flanges 21 which are adapted to be slidably received ; in the channel 10 of stringer 1. Once positioned, the riser plate 2 may be permanently attached to the ~tringer member 1 by means of metal screws or rivets 24 whose proper : alignment may be facilitated with the aid of longitudinal grooves 8:on the top outer surface of the stringer member 1 ~ ~ :on either s~ide of:the slot 10a as shown in FIG 2. The ~d~30~ upper edge 25 of riser plate 2 is pre-cut for a desired ~-~ staircase angle of inclination so that the said upper edge is substantially horizontal when riser plate 2 has been , . . .
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131~068 fastened to stringer member 1. Run member 3, cut to the approximate length of upper edge 25 of riser plate 2, is of a generally T-shaped form and comprises an upper support surface 27 and two downwardly extending parallel ribs 26 which define a gap adapted to receive upper edge 25 of riser plate 2. After the run member 3 is placed on riser plate 2, suitable fasteners 23 such as screws or rivets, may be employed to permanently secure them together.
Longitudinal grooves 29 may be provided along the outside surfaces of ribs 26 so as to provide a means for aligning the positions of fasteners 23. The support surface 27 of riser member 3 may be provided with a plurality of holes, as at 28, for receiving screws or other suitable fasteners in order to provide for the secure attachment of tread 4.
The construction of stringer member 1 is shown more clearly in FIG 2. A spacing rod or plate 7 of a predetermined length may be slidably inserted into the open channel 10 so as to conveniently and consistently position the riser plates 2 at desired spaced apart intervals along the length of the stringer member 1. A lower channel 18 is also provided and the channels 10 and 18 may respectively slldably receive straight or angled flat joining members 17 (FIG 5) for joining two sections of stringer members 1.
Fastening means such as screws (not shown) secure the ~oining members 17 to the stringer members. The inside surfaces of stringer member 1 also contain four integral longitudinal channels 9 extending the entire length of the stringer member 1 and having a generally arcuate C-shaped cross-sectional profile. Longitudinal channels g are disposed in a spaced apart relationship and may be threaded (tapped) for receiving attachment screws which permit the stringer members 1 to be secured to suitable ' ' ' ' .

13~068 g support surfaces or end plates in the manner to be described more fully hereinbelow. Longitudinal channels 9 are also pro~ided with inwardly extending ridges 19 which are adapted to slidably receive and constrain a reinforcing member 6 (FIG 2) which may be used whenever added strength and rigidity is desired for a particular staircase installation or use.
Referring now to FIGS 3, 4, 5 and 6, there is shown a typical staircase installation making use of the staircase stringer assembly according to the present invention. The particular arrangement shown includes a first flight of steps 4a which leads to a landing 11, wherefrom a second flight of steps 4b is provided transversely to the first flight, the second flight of steps terminating at a balcony 13 or or a higher floor. Beginning with the first flight of steps 4a, the lower terminal ends 30 of the stringer members 1 are attached to a mounting plate 16 (FIG

4) by way of screws which are received through the said mounting plate and held by the tapped longitudinal channels 9 previously described. Mounting plate 16 is in turn affixed to the ground by attachment to a concrete footing or the like as is well known to those skilled in this art.
The staircase stringer assembly is then constructed as previously described by use of the spacing bars 7. At the upper terminal ends 33 of the first flight of steps 4a (FIG

5), the stringer members 1 are joined to horizontally disposed stringer members which advantageously are used as ~oist members 15 for supporting the landing surface 11.
The ~oining of the upper terminal end 33 of a stringer member 1 of the first flight of steps 4a to the joist member 15 is by way of angled flat ~oining members 17 slidably inserted into the open channels 10 and 18 of each ' .

, - lO_ 131~068 member. Other stringer members 1 may be disposed horizontally as at 34 and 35 transversely to the joist members 15 so as to form a support structure for landing 11, as shown in FIG 3. A support post 36 may extend downwardly from one such horizontally disposed stringer member, such as member 34, in order to support the structural frame of landing 11 so formed by the stringer members.
A second flight of steps 4b may commence at landing 11 by fixedly attaching a pair of stringer members 14 to joist member 15. The upper terminal ends 32 of stringer members 14 (FIG 6) may be attached to an end plate 12 for securing the second flight of steps 4b to balcony 13.
Various changes may be made to the embodiments described herein without departing from the scope of the present invention which is limited only by the following claims.

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Claims (14)

1. A staircase stringer assembly for supporting a plurality of stair treads, said staircase stringer assembly comprising:
at least two stringer members angularly disposed in a laterally spaced apart and substantially parallel relationship, said stringer members each respectively providing an outwardly open channel extending longitudinally the entire lengths thereof;
a plurality of riser members adapted for slidable interconnection with said open channels of said stringer members and identically disposed therein at predetermined spaced apart intervals;
a plurality of corresponding run members, said run members being adapted to cooperatively engage with said riser members and providing a substantially flat surface for supporting said stair treads.

2. A staircase stringer assembly according to Claim 1 wherein:
said stringer members have a rectangular hollow cross-sectional configuration, the said outwardly open channel being disposed therein along the entire longitudinal lengths thereof;
said riser members consist of flat plates each having transversely extending lower flanges for slidable engagement with said outwardly open channel and each providing a substantially horizontal upper edge;
said run members comprise flat plates with two parallel and downwardly extending ribs for receiving therebetween the said upper edge of said riser members, said run members each further providing a substantially planar and horizontal surface for supporting a stair tread.

3. The staircase stringer assembly according to Claim 2, wherein said stringer members, along the inside surfaces thereof, are each provided with integral flutes running the entire longitudinal lengths thereof and forming slots having a generally C-shaped cross-section, said flutes being adapted for receiving fastening means to thereby permit the stringer members to be secured to suitable support surfaces or end plates, said stringer members each further having an integral lower channel running the entire longitudinal lengths thereof, said outwardly open channel and said lower channel being adapted to respectively slidably receive flat plate members for joining two sections of stringer members.

4. A staircase stringer assembly according to Claim 3, wherein said stringer members are adapted to contain a reinforcing member.

5. A staircase stringer assembly according to any one of Claims 2, 3 and 4, wherein spacing means are disposed in said outwardly open channels to thereby position the riser plates along the lengths of said stringer members.

6. A staircase stringer assembly according to any one of Claims 2, 3 and 4, wherein said stringer members, said extruded riser members and said run members are composed of aluminum alloy.

7. A staircase stringer assembly comprising a stringer member, a plurality of riser members and a plurality of run members, said stringer member comprising an elongated hollow member having a flat top surface and a first channel beneath said top surface, said top surface having a slot communicating with said channel, each said riser member comprising a flat plate having a top edge and a bottom edge, said top edge comprising a support for a run member and said bottom edge having transversely extending flanges adapted to be received in said channel, said run member comprising a flat plate having two depending ribs adapted to be disposed on either side of the riser member, said riser member being secured to said stringer and said run member being secured to said riser member.

8. An assembly as claimed in Claim 7 wherein the top edge of said riser member is formed at a predetermined angle with respect to the top surface of said stringer member so that when the stringer is installed to form a staircase the top edge of the riser member is substantially horizontal.

9. An assembly as claimed in Claim 8 wherein said stringer member, said riser member and said run member are formed of extruded metal.

10. An assembly as claimed in Claim 9 wherein said stringer member includes means for receiving a longitudinally extending reinforcing member.

11. An assembly as claimed in Claim 7 wherein said stringer member has a plurality of longitudinally extending flutes forming generally C-shaped slots adapted to receive fastening means for securing the stringer member to a support surface.

12. An assembly as claimed in Claim 11 wherein said stringer member has a flat bottom surface and a second channel beneath said bottom surface, said first and second channels being adapted to receive flat plate members for joining two stringer members together.

13. An assembly as claimed in Claim 12 including spacer members disposed in said channels to properly space apart said riser members along the length of said stringer member.

14. An assembly as claimed in Claim 13 wherein said stringer member, said riser members and said run members are formed of aluminum alloy.