Note: Descriptions are shown in the official language in which they were submitted.
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TITLE OF INVENTION
STRINGER CONNECTOR AND STAIRCASE
FIELD OF THE INVENTION
This invention relates to staircases. In particular, this invention relates to
modular staircases having stringers as structural elements.
iii BACKGROUND OF THE INVENTION
Staircase stringers are commercially available in fixed lengths, each length
generally corresponding to a respective number of steps. Depending upon the
elevation difference between the substrate or lower structure and the elevated
is structure that the staircase is intended to span, a single stringer may not
be
adequately long enough. Accordingly, it would be advantageous if staircase
stringers could be rigidly attached to each other to form a longer composite
stringer assembly.
20 Further, fixed-length staircase stringers are generally only commercially
available up to a certain length, as beyond that point it becomes too
expensive
and/or heavy to conveniently manufacture stringers strong enough to support
the increased span. Accordingly, it would be advantageous if smaller
stringers could be connected together and mounted on an intermediate
25 supporting structure to construct staircases for tall elevated structures,
such
as second-floor decks.
It is therefore an object of this invention to provide a stringer connector
for
rigidly assembling staircase stringers together. It is a further object of the
30 invention to provide a staircase constructed from such composite stringer
assemblies. .
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These and other objects will be better understood by reference to this
application as a whole. Not all of the objects are necessarily met by all
embodiments of the invention described below or by the invention defined by
each of the claims.
SUMMARY OF THE INVENTION
In one aspect, the invention comprises a stringer connector for connecting a
first staircase stringer to a second staircase stringer. The stringer
connector
comprises a base and side walls extending from the base, the base and side
walls together defining, at least in part, a channel. The channel has first
and
second ends and may be semi-rectangular in cross-section. First and second
tabs extend from the base into the channel. The base further comprises a
is surface in the channel. First ridges are preferably formed in the surface
extending inwards from the first end. Second ridges are preferably formed in
the surface extending inwards from the second end. One or more first
openings are formed through the side walls proximate to the first end. One or
more second openings are formed through the side walls proximate to the
second end.
To connect the first stringer to the second stringer using the stringer
connector, a second stringer end of the first stringer is inserted into the
first
end of the channel until the second stringer end of the first stringer is
proximate to the first tab. A first stringer end of the second stringer is
inserted
into the second end of the channel until the first stringer end of the second
stringer is proximate to the second tab. The first stringer and second
stringer
are preferably further inserted until the first stringer contacts at least one
of the
second stringer and the first tab, and the second stringer contacts at least
one
of the first stringer and the second tab. Fasteners are then inserted into the
first and second openings and through the first and second stringers,
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respectively, to rigidly attach the stringer connector to the first and second
stringers. The first and second stringers are spaced apart from the surface by
the first and second ridges, respectively.
In another aspect, the stringer further comprises a bracket for attaching the
stringer connector to an intermediate support structure.
In another aspect, the invention comprises a staircase comprising a plurality
of
stringer assemblies and one or more treads extending across and connecting
io the stringer connector assemblies. Each stringer assembly comprises the
first
stringer, the second stringer, and the stringer connector. Each of the first
stringers may contact, or be attached to, a substrate. Each of the second
stringers may be attached to an elevated structure. Each of the stringer
connectors will preferably be attached to the intermediate support structure.
According to another aspect of the invention, a stringer connector for rigidly
connecting a first stringer to a second stringer in a staircase comprises a
base, two side walls extending from the base, wherein the base and the side
walls define, at least in part, a channel having a first end and a second end,
and wherein the channel is adapted to receive the first stringer at the first
end
and the second stringer at the second end, a first tab extending into the
channel from the base, the first tab limiting a first depth of insertion of
the first
stringer, a second tab extending into the channel from the base, the second
tab limiting a second depth of insertion of the second stringer, a plurality
of
openings extending through both of the side walls and adapted to receive a
plurality of fasteners for securing the first and second stringers to the
stringer
connector.
According to a further aspect, the first stringer contacts the second
stringer/
The first stringer may contact the first tab and the second stringer may
contact
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the second tab. The stringer connector of claim 1, wherein the first stringer
contacts the second stringer.
According to a further aspect, the channel has a midpoint. The first tab may
be disposed between the first end and the midpoint. The second tab may be
disposed between the second end and the midpoint. A first distance between
the first tab and the midpoint may be equal to a second distance between the
midpoint and the second tab.
iii According to a further aspect, the base comprises a surface disposed at
least
in part between the side walls, one or more first ridges extending inward from
the first end and extending from the surface into the channel, wherein the one
or more first ridges are adapted to support the first stringer such that the
first
stringer is spaced apart from the surface, and one or more second ridges
is extending inward from the second end and extending from the surface into
the
channel, wherein the one or more second ridges are adapted to support the
second stringer such that the second stringer is spaced apart from the
surface. The one or more first ridges and the one or more second ridges may
each comprise three ridges.
According to a further aspect, the stringer connector comprises a bracket
extending from the base for attaching the stringer connector to a
substantially
vertical support post. The first tab may be oriented substantially vertically
when the bracket is attached to the support post. The second tab may be
oriented substantially horizontally when the bracket is attached to the
support
post. The bracket may comprise a plurality of stiffening ribs on a periphery
of
the bracket. The bracket may extend from the base at an acute angle relative
to the first end.
According to a further aspect, the stringer connector is made from metal. The
metal may be steel.
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According to another aspect of the invention, a staircase comprises a
plurality
of laterally spaced apart stringer assemblies, each of the stringer assemblies
comprising, a first stringer, a second stringer, a stringer connector, the
stringer
5 connector comprising, a base, two side walls extending from the base,
wherein the base and the side walls define, at least in part, a channel having
a
first end and a second end, a first tab extending into the channel from the
base, a second tab extending into the channel from the base, and a plurality
of
openings, each opening extending through both of the side walls, and a
plurality of fasteners, wherein the first stringer is received in the channel
from
the first end and contacts at least one of the first tab and the second
stringer,
the second stringer is received in the channel from the second end and
contacts at least one of the second tab and the first stringer, at least a
first
fastener of the plurality of fasteners received in a first opening of the
plurality
is of openings and extending through the first stringer, and at least a second
fastener of the plurality of fasteners received in a second opening of the
plurality of openings and extending through the second stringer; and one or
more treads extending across and connecting the stringer assemblies.
According to a further aspect, the base comprises a surface, one or more first
ridges extending inward from the first end and extending from the surface into
the channel, and one or more second ridges extending inward from the
second end and extending from the surface into the channel, wherein the one
or more first ridges are adapted to support the first stringer such that the
first
stringer is spaced apart from the surface, and wherein the one or more
second ridges are adapted to support the second stringer such that the
second stringer is spaced apart from the surface.
According to a further aspect, the staircase comprises a substantially
vertical
intermediate support structure and wherein each of the stringer connectors
further comprises a bracket extending from the base for attaching the stringer
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connector to the intermediate support structure. The intermediate support
structure may be made from wood.
According to a further aspect, each of the first and second stringers and the
stringer connectors are made from metal.
According to a further aspect, each of the first stringers contact a substrate
and each of the second stringers attach to an elevated structure. The first
stringers may be attached to the substrate.
iii
According to a further aspect, the plurality of stringer assemblies comprises
two stringer assemblies and wherein each of the treads are 122 centimeters
long or shorter.
is The foregoing may cover only some of the aspects of the invention. Other
and sometimes more particular aspects of the invention will be appreciated by
reference to the following description of at least one preferred mode for
carrying out the invention in terms of one or more examples. The following
mode(s) for carrying out the invention are not a definition of the invention
20 itself, but are only example(s) that embody the inventive features of the
invention.
BRIEF DESCRIPTION OF THE DRAWINGS
25 At least one mode for carrying out the invention in terms of one or more
examples will be described by reference to the drawings thereof in which:
Fig. 1 is a front perspective view according to a first embodiment of the
invention of a stringer connector;
30 Fig. 2 is a rear perspective view of the stringer connector of Fig. 1;
Fig. 3 is an end view of the stringer connector of Fig. 1;
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Fig. 4 is a top view of the stringer connector of Fig. 1;
Fig. 5 is a section view of the stringer connector of Fig. 1 taken along
line 5-5 of Fig. 4;
Fig. 6 is a perspective view according to a preferred embodiment of the
invention of a stringer connector;
Fig. 7 is a side view of the stringer connector of Fig. 6;
Fig. 8 is a perspective view of the stringer connector of Fig. 6 mounted
to an intermediate support structure;
Fig. 9 is a perspective view of the stringer connector of Fig. 6 showing
io the insertion of a first stringer and a second stringer;
Fig. 10 is a perspective view of the stringer connector of Fig. 6 with the
first and second stringers inserted, showing the insertion of fasteners;
Fig. 11 is a section view of the stringer connector and first and second
stringers of Fig. 10, taken along line 5-5 as in Fig. 4; and
Fig. 12 is a perspective view of a staircase constructed using the
stringer connector of Fig. 6.
DETAILED DESCRIPTION
Referring to Figs. 1-5, according to an embodiment of the invention, a
stringer
connector 100 comprises a base 102 and two side walls 104, 106. The side
walls 104, 106 extend from the base 102, with the side walls 104, 106 and the
base 102 defining, at least in part, a channel 108. The channel 108 has a
first
channel end 110 and a second channel end 112. Preferably each of the base
102 and the side walls 104, 106 are substantially planar, and the side walls
104, 106 are parallel and extend substantially orthogonally from the base 102,
such that the channel 108 is substantially semi-rectangular in cross-section
(as shown, for example, in Fig. 3). However, other configurations for the
channel 108 are possible without departing from the scope of the invention.
Preferably the base 102 and side walls 104, 106 are integral with each other
or otherwise rigidly attached together, such as through welding or another
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suitable process. One or more first openings 124 are formed through the side
walls 104, 106 proximate to the first channel end 110 and one or more second
openings 126 are formed through the side walls 104, 106 proximate to the
second channel end 112.
The base 102 further comprises a first tab 114 which extends into the channel
108 and at a first angle 0 from the base 102, and a second tab 116 which
extends into the channel 108 and at a second angle cp from the base 102, as
best shown in Fig. 5. The first angle 0 and the second angle cp may be equal.
io The first and second tabs 114, 116 are preferably integral with the base
102
and formed using any suitable process, such as lancing, or are otherwise
rigidly attached to the base 102.
The base 102 preferably further comprises a surface 118 which forms
is substantially the bottom of the channel 108. One or more first ridges 120
extend into the channel 108 from the surface 118 and along at least a portion
of the surface 118 from the first channel end 110. One or more second ridges
122 extend into the channel 108 from the surface 108 and along at least a
portion of the surface 118 from the second channel end 112. Preferably, the
20 first and second ridges 120, 122 do not extend along the full length of the
surface 118, but instead terminate before the first tab 114 and second tab
116, respectively, as shown. However, in some embodiments, the first and
second ridges 120, 122 are unitary with each other and run the entire length
of
the surface 118. The first and second ridges 120, 122 are preferably integral
25 with the surface 118 and may be formed by any suitable method, such as
stamping or corrugating. As shown, there are preferably three first ridges 120
and three second ridges 122.
Referring to Figs. 6-8, the stringer connector 100 preferably further
comprises
30 a bracket 128 extending from the base 102. The bracket 128 comprises a
vertical channel portion 130 and an angled portion 132 which connects the
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vertical channel portion 130 to the base 102. The bracket 128 is adapted to
attach the stringer connector 100 to an intermediate support structure 40. The
intermediate support structure 40 may comprise, as a non-limiting example, a
vertical post 42. The vertical post 42 may be made of dimensional lumber,
such as a 4x4. The vertical channel portion 130 is adapted to mount on a top
end 44 of the vertical segment 42 as best shown in Fig. 11. The vertical
channel portion 130 preferably further comprises one or more stiffening ribs
134 formed on a periphery of the vertical channel portion 130. The vertical
channel portion 130 preferably further comprises one or more third openings
io 136 which are adapted to receive mechanical fasteners such as nails or
screws for mounting the vertical channel portion 130 to the vertical post 42.
The angled portion 132 is generally wedge-shaped and angles the channel
108 relative to the vertical channel portion 130 at the desired slope of the
staircase to be completed. As a non-limiting example, the angled portion 132
may be a wedge with a taper angle of 27 degrees, and accordingly the
channel 108 will be angled at 27 degrees relative to a horizontal plane, which
corresponds approximately to a staircase having a half-meter rise over meter
run. Further, in one embodiment, the first tab 114 is oriented preferably
substantially vertical and the second tab 116 is preferably oriented
substantially horizontal when the bracket 128 is attached to the intermediate
support structure 40.
Referring to Figs. 9-11, a staircase stringer 10 generally comprises a first
stringer end 12 and a second stringer end 14. The stringer connector 100
rigidly connects a first stringer 10A to a second stringer 10B in the
following
manner. The second stringer end 14A of the first stringer 10A is inserted into
the first end 110 of the channel 108, as indicated by the arrow in Fig. 9,
until
the second stringer end 14A of the first stringer 10A is proximate to or
contacts the first tab 114. The first tab 114 thus acts as a stop to prevent
the
first stringer 10A from being inserted too far into the channel 108. The
second
stringer end 14A is preferably beveled at the first angle 8 so that the second
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stringer end 14A will sit substantially flush against the first tab 114,
should it
contact the first tab 114, as best shown in Fig. 11. Fasteners 30 can then be
inserted into the first openings 124 and driven through the first stringer
10A,
as indicated by the arrows in Fig. 10, in order to rigidly attach the first
stringer
5 10A to the stringer connector 100. Similarly, the first stringer end 12B
of the
second stringer 10B is inserted into the second end 112 of the channel 108
until the first stringer end 12B of the second stringer 10B is proximate to,
or
contacts the second tab 116. The second tab 116 thus acts as a stop to
prevent the second stringer 10B from being inserted too far into the channel
iii 108 The first stringer end 12B is preferably beveled at the second
angle cp so
that the first stringer end 12B will sit substantially flush against the
second tab
116, should it contact the second tab 116, as best shown in Fig. 11.
Fasteners 30 can then be inserted into the second openings 126 and driven
through the second stringer 10B to rigidly attach the second stringer 10B to
is the stringer connector 100. Holes may be pre-formed in the first and second
stringers 10A, 10B that align with the first and second openings 124, 126 to
facilitate use of the fasteners 30. The fasteners 30 may include nuts and
bolts
or rivets, or other mechanical fasteners. In one embodiment, the first and
second stringers 10A, 10B are of the same length, as shown in Fig. 6, but in
.. other embodiments, may also be of differing lengths. In one embodiment, the
second stringer end 14A of the first stringer 10A preferably contacts at least
one of the first tab 114 and the first stringer end 12B of the second stringer
10B, as best shown in Figs. 10 and 11. Similarly, the first stringer end 12b
of
the second stringer 10B preferably contacts at least the second stringer end
14A of the first stringer 10A and the second tab 116, as best shown in Figs.
10
and 11. These contacts ensure that the first and second stringers 10A, 10B
are inserted sufficiently far into the channel 108 to allow them to be
securely
fastened to the stringer connector 100, while at the same time ensuring that
the first and second stringers 10A, 10B are appropriately positioned in the
stringer connector 100 to account for various structural considerations within
an acceptable range delimited by the first tab 114 and the second tab 116. As
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a non-limiting example, the embodiment of the stringer connector 100 shown
in Figs 8-11 is intended for use with first and second stringers 10A, 10B of
equal length and it is therefore desirable that the first and second stringers
10A, 10B are inserted in a way that balances the structural loads on opposing
sides of a midpoint 138 of the channel 108. Accordingly, the first tab 114 is
preferably disposed between the first end 110 and the midpoint 138 of the
channel 108 and the second tab 116 is preferably disposed between the
midpoint 138 and the second end 112. If the second stringer 10B contacts the
second tab 116 and the first stringer 10A as shown in Fig. 11, then the
iii structural loads are at the leftmost limit for an acceptable range of
balance
about the midpoint 138. Conversely, if the first stringer 10A contacts the
first
tab 114 and the second stringer 10B, then the structural loads are at the
rightmost limit of the acceptable range for balance about the midpoint 138.
However, it will be recognized that it may be necessary to position the tabs
is 114, 116 in a variety of locations within the channel 108, including
having both
tabs 114, 116 between the midpoint 138 and the first end 110, or between the
midpoint 138 and the second end 112, and so doing will not depart from the
scope of the invention.
20 The first stringer 10A is preferably spaced apart from the surface 118 by
the
first ridges 120. This allows the second stringer end 14A to contact the first
tab 114 without any interference from manufacturing considerations between
the first tab 114 and the base 102, such as bend radii, weld beads, and the
like. Similarly, the second stringer 10B is preferably spaced apart from the
25 surface 118 by the second ridges 122. Additionally, the first and second
ridges
122, 124 strengthen the respective first and second ends 110, 112 of the
channel 108 and allow any liquid, such as rain, to drain out of the channel
108
between the first and second ridges 120,122 and the first and second
stringers 10A, 10B.
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Referring to Fig. 12, according to another embodiment of the invention a
staircase 200 comprises a plurality of laterally spaced apart stringer
assemblies 202 and one or more treads 204 extending across and connecting
the stringer assemblies 202. Each stringer assembly 202 comprises first
stringer 10A connected to second stringer 10B by stringer connector 100 as
previously described. Each of the stringer connectors 100 is preferably
attached to intermediate support structure 40, which preferably comprises a
plurality of vertical posts 42 connected by cross-bracing 46.
iii In some embodiments where the width of the treads is 122 cm (4 feet) or
less,
two spaced apart stringer assemblies are sufficient.
However, for
embodiments where the staircase is required to be wider, additional spaced
apart stringer assemblies may be necessary.
is In some embodiments, the first stringer 10A of each stringer assembly 200
spans from a substrate 5 to the intermediate support structure 40. The
substrate 5 may be, as non-limiting examples, the ground, a concrete pad, a
lower structure such as a landing, and the like. The first stringer end 12A of
the first stringers 10A may contact the substrate 5 and/or be attached to the
20 substrate 5 by adhesives, mechanical fasteners, or other suitable methods.
The second stringers 10B span from the intermediate support structure 40 to
an elevated structure 50 such as a deck, landing, entranceway, and the like.
In other embodiments, two or more of the intermediate support structures 40
of different elevations can be used for even longer staircases. The first or
25 second stringers 10A, 10B may accordingly span between intermediate
support structures 40.
The stringer connector 100 and stringers 10 are preferably made from a metal
and even more preferably made from steel, which is favourable due to factors
30 such as, but not limited to, cost, ductility, strength/weight ratio,
weldability, and
weather resistance.
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To construct the staircase 200, each stringer assembly 202 is first assembled
by laying the first and second stringers 10A, 10B upside-down on a surface.
The first and second stringers 10A, 10B can then be inserted into the stringer
connector 100 so that the first stringer 10A contacts at least one of the
first tab
114 and the second stringer 10B, and the second stringer 10B contacts at
least one of the first stringer 10A and the second tab 116. This ensures that
the first and second stringers 10A and 10B are both sufficiently and equally
inserted, within an acceptable range, to appropriately balance the structural
iii loads associated with the staircase 200 and transfer those structural
loads
evenly to the intermediate support structure 40 through the brackets 128. If
necessary, the position of the first and second openings 124, 126 can be
marked on the first and second stringers 10A, 10B, respectively so that the
first and second stringers 10, 20 can be drilled and/or tapped for the
fasteners
is 30. The fasteners 30 are inserted into the first and second openings
124, 126
and through the first and second stringers 10A, 10B to rigidly connect the
first
and second stringers 10A, 10B to the stringer connector 100. Each stringer
assembly 202 can then be mounted to the intermediate support structure 40,
fastened to the elevated structure 50, and fastened to the substrate 5 if
20 necessary. Finally, the treads 204 can be attached to the stringer
assemblies
202.
In the foregoing description, exemplary modes for carrying out the invention
in
terms of examples have been described. However, the scope of the claims
25 should not be limited by those examples, but should be given the broadest
interpretation consistent with the description as a whole. The specification
and drawings are, accordingly, to be regarded in an illustrative rather than a
restrictive sense.
