Note: Descriptions are shown in the official language in which they were submitted.
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~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.
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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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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
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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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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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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
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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
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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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