Note: Descriptions are shown in the official language in which they were submitted.
CA 02568444 2006-11-21
JOIST SUPPORT
BACKGROUND
The present invention relates to the field of structural members, and
more particularly concerns joist support members, including but not limited to
those referred to as rim tracks for use in metal floor support systems.
Traditional floor systems are made of wood. There is generally a
member, referred to as a rim board, which is positioned on top of a wall
around
the perimeter of a room or at desired locations of floor support in a
building.
Joists bear on the wall, span between the rim boards, and are fastened to the
lo rim boards at spaced intervals. The joist spacing is usually consistent,
such as
12 inches, 16 inches, or 24 inches. Fastening is most often done with nails,
preferably from the opposite side of the rim board, but if the opposite side
of the
rim board is not accessible, toe nailing the joist to the rim board is
necessary.
Alternatively, a joist hanger, for which there are numerous designs, may be
used to attach the joist to the rim board, but this adds expense to the
installation.
As an alternative to wood framing and floor systems, cold-formed light
gauge steel has relatively recently come into use. Such steel floor systems
include a member that is referred to as a rim track and performs the function
of
2o a wood rim board. Often the rim track is a C-shaped member, though the
cross-sectional shape may vary. Joists, which also may vary in shape but are
most commonly also C-shaped in cross-section, span between rim tracks and
are fastened to the rim tracks at spaced intervals. Though the structural
characteristics of the steel members may be varied as desired based on
specification of the shape, thickness, and grade of steel, to conform to
traditional construction standards and practice the spacing is usually the
same
as is used for wood.
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The exact design of the rim tracks and joists may vary; for example,
there may be penetrations through both to allow passage of utility lines,
there
may embossed portions for reinforcing, or there may be integral features of
the
rim track that allow fastening of the joist to the rim track. With the
exception of
rim tracks including integral features for fastening joists, such as spaced
tabs,
conventional wood rim boards and steel rim tracks require measurement and
marking of the spacing on the component to allow correct placement of the
joists. Conventional rim tracks and joists may be fastened using clips, or L-
shaped angle members. Associated measurement and marking along the rim
lo track must be done with care at significant expense for the labor involved
in
constructing the system. Rim tracks with integral tabs require special tooling
and care in forming the tabs and bending them to the desired angle. They also
require more space to ship than rim tracks with a completely planar web, are
generally more difficult to ship, and require care to avoid undesired bending
of
tabs.
Accordingly, there exists a need for a rim track that facilitates installation
of joists and is relatively simple to fabricate. Ideally the rim track will
have
characteristics that do not require particularly complex roll forming,
punching,
and bending equipment, and that provide for efficient shipping.
SUMMARY
In accordance with an embodiment of the present invention, a structural
member for supporting joists is provided. The structural member includes a
web having a central longitudinal axis and a substantially planar profile. The
structural member includes a plurality of longitudinally spaced slots through
the
web substantially perpendicular to the longitudinal axis of the web. The edges
of the web that define the slots extend no more than 1/2 inch from the planar
profile of the web, and may be substantially flush with the planar profile of
the
web.
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In accordance with another embodiment of the present invention,
another structural member for supporting joists is provided. The structural
member includes a web having a central longitudinal axis. There is a plurality
of longitudinally spaced slots through the web substantially perpendicular to
the
longitudinal axis of the web. The web is substantially free of joist
attachment
tabs, and may be substantially free of any type of tabs.
In accordance with another embodiment of the present invention, a floor
support system is provided. The floor support system includes a plurality of
joists, a rim track member, and elongated mounting members. The rim track
member includes a web having a central longitudinal axis and includes
longitudinally spaced slots through the web that are substantially
perpendicular
to the longitudinal axis of the web. The elongated mounting members are for
mounting the joists to the rim track member. Each mounting member includes
a first arm and a second arm separated by an interior angle, and each arm has
an interior face and an exterior face. The first arm extends through a
corresponding slot and is fastened to an end of a joist. The second arm is
fastened to the rim track member web, and the second arm interior face abuts
the rim track member web.
In accordance with another embodiment of the present invention, a floor
support system is provided. The floor support system includes a plurality of
joists, a rim track member, and means for mounting the joists to the rim track
member. The rim track member includes a web having a central longitudinal
axis and includes longitudinally spaced slots through the web that are
substantially perpendicular to the longitudinal axis of the web. Each means
for
mounting extends through a corresponding slot and is fastened to an end of a
joist.
In accordance with another embodiment of the present invention, a floor
support system is provided, including a first wall with a top surface, a
second
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wall spaced from the first wall and also with a top surface, a first rim track
member, a second rim track member, a plurality of joists, and elongated
mounting members. The first and second rim track members each include a
web having a central longitudinal axis and include longitudinally spaced slots
through the web. The slots are substantially perpendicular to the longitudinal
axis of the web. The slots in the second rim track member are substantially
aligned with the slots in the first rim track member. The plurality of joists
has
two ends and extends between the substantially aligned slots in the first and
second rim track members. The elongated mounting members are for
1o mounting the joists to each rim track member. Each mounting member includes
a first arm and a second arm separated by an interior angle, and each arm has
an interior face and an exterior face. The first arm extends through a
corresponding slot and is fastened to an end of one of the plurality of
joists.
The second arm is fastened to the rim track member web, and the second arm
interior face abuts the rim track member web.
In accordance with another embodiment of the present invention, a
method of making a joist support member includes providing a structural
member including a web having a central longitudinal axis and a substantially
planar profile. A plurality of longitudinally spaced slots is formed through
the
web. The slots are substantially perpendicular to the longitudinal axis of the
web. The edges of the web that define the slots extend no more than 1/2 inch
from the planar profile of the web, and may be substantially flush with the
planar
profile of the web.
In accordance with another embodiment of the present invention, a
method of assembling a joist support apparatus is provided. A joist support
member is provided that includes a web having a central longitudinal axis and
a
substantially planar profile. The joist support member further includes a
plurality of longitudinally spaced slots through the web, with the slots
substantially perpendicular to the longitudinal axis of the web. An elongated
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mounting member is provided, including a first arm and a second arm
separated by an interior angle. Each arm has an interior face and an exterior
face. One arm is inserted through a corresponding slot, and one arm is
fastened to the joist support member web such that the interior face of the
arm
being fastened abuts the joist support member web.
In accordance with another embodiment of the present invention, a
method of assembling a joist support system is provided. A joist support
member is provided that includes a web having a central longitudinal axis and
a
substantially planar profile, and a plurality of longitudinally spaced slots
through
the web. The slots are substantially perpendicular to the longitudinal axis of
the
web. A joist and an elongated mounting member are provided. The elongated
mounting member includes a first arm and a second arm separated by an
interior angle. Each arm has an interior face and an exterior face. One arm is
inserted through a corresponding slot. One arm is fastened to the joist
support
member web such that the interior face of the arm being fastened abuts the
joist
support member web. The remaining arm is fastened to an end of a joist.
In accordance with another embodiment of the present invention, a
method of constructing a floor system is provided. The method includes
constructing spaced apart first and second walls each having a top surface. A
first rim track member is disposed on the top surface of the first wall and a
second rim track member is disposed on the top surface of the second wall.
The first and second rim track members each include a web having a central
longitudinal axis and including longitudinally spaced slots through the web
substantially perpendicular to the longitudinal axis of the web. The rim track
members are positioned such that corresponding slots are substantially
aligned.
First and second elongated mounting members are provided, each including a
first arm and a second arm separated by an interior angle. An arm of the first
elongated mounting member is inserted into a slot in the first rim track
member,
and an arm of the first elongated mounting member is fastened to the first rim
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track web. An arm of the second elongated mounting member is inserted into a
slot in the second rim track member. This slot is substantially aligned with
the
slot in the first rim track member in which the first elongated mounting
member
is disposed. An arm of the second elongated mounting member is fastened to
the second rim track web. A joist, having first and second ends, is positioned
such that the joist extends between the first and second elongated mounting
members. The first end of the joist is fastened to an arm of the first
elongated
mounting member, and the second end of the joist is fastened to an arm of the
second elongated mounting member.
Features and advantages of the present invention will become more
apparent in light of the following detailed description of some embodiments
thereof, as illustrated in the accompanying figures. As will be realized, the
invention is capable of modifications in various respects, all without
departing
from the invention. Accordingly, the drawings and the description are to be
regarded as illustrative in nature, and not as restrictive.
BRIEF DESCRIPTION OF THE DRAWINGS
FIGS. 1 and 2 are perspective views of prior art rim track and joist
connections.
FIG. 3 is a perspective view of a rim track and joist connection in
accordance with an embodiment of the present invention.
FIGS. 4 and 5 are perspective views of rim track and connection member
assembly methods of the rim track and joist of FIG. 3 in accordance with
embodiments of the present invention.
FIG. 6 is a perspective view of a floor support system including the rim
track and joist connection of FIG. 3.
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FIG. 7 is a perspective view of a member for use in the rim track and
connection member assembly of FIG. 3 in accordance with an embodiment of
the present invention.
DESCRIPTION
In the Figures herein, unique features receive unique reference
numerals, while features that are the same in more than one drawing receive
the same reference numerals throughout. Further, certain terms of orientation
may be used, such as "front," "back," "interior," "top," "bottom," "left,"
"right,"
"vertical," and "horizontal." These terms are generally for convenience of
reference, and should be so understood unless a particular embodiment
requires otherwise.
The scope of the invention is not intended to be limited by materials
listed herein, but may be carried out using any materials that allow
construction
and operation. Materials and dimensions depend on the particular application.
In general the materials of the components may be metal, and in particular may
include cold-formed light gauge steel, which may or may not include a surface
treatment such as galvanizing. All dimensions discussed herein are by way of
example.
The present invention will be described in terms of specific, ekample
2o embodiments. It is to be understood that the invention is not limited to
the
example embodiments disclosed. It should also be understood that not every
feature of the devices or methods described are necessary to implement the
invention as claimed in any particular one of the appended claims. Various
elements, steps, processes, and features of various embodiments of devices
and processes are described in order to fully enable the invention. It should
also be understood that throughout this disclosure, where a process or method
is shown or described, the steps of the method may be performed in any order
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or simultaneously, unless it is clear from the context that one step depends
on
another being performed first.
Referring now to the drawings, a prior art rim track and joist assembly 20
is shown in FIG. 1. The assembly 20 includes a rim track 22, a joist 24, and a
clip 26 that is used to mount the joist 24 to the rim track 22. The rim track
22 is
C-shaped and includes a central web 28, an upper leg 30 that extends
perpendicularly from the top edge of the web 28, and a lower leg 32 that
extends perpendicularly from the bottom edge of the web 28 in the same
direction as the upper leg 30. In general there are not penetrations through
the
1o web 28 other than for fasteners. The rim track 22 rests on top of a wall
34, and
may be fastened to the wall 34 periodically with fasteners 36, such as screws
or
other anchors, through the lower leg 32. The wall 34 may be, for example,
block, concrete, or steel or wood framing.
The joist 24 is also C-shaped and includes a central web 38, an upper
leg 40 that extends perpendicularly from the top edge of the web 38, and a
lower leg 42 that extends perpendicularly from the bottom edge of the web 38
in
the same direction as the upper leg 40. The joist 24 is mounted to the rim
track
22 with the clip 26, which is an elongated mounting member that is an L-shaped
angle (bent at 90 degrees) with two arms 44, 46 and an interior angle between
the two arms 44, 46. One arm 44 of the clip 26 is fastened to the front side
of
the web 28 of the rim track 22 and the other arm 46 of the clip 26 is fastened
to
the back side of the joist web 38. When reference is made herein to the front
side of the rim track, joist, or their respective webs, it should be
understood that
the front side is the side towards which the legs extend. Conversely, when
reference is made herein to the back side of the rim track, joist, or their
respective webs, it should be understood that the back side is the side away
from which the legs extend. As alternatives to the configuration shown in FIG.
1, the arm 46 attached to the joist 24 could be attached to the back side of
the
joist web 38 with the joist legs 40, 42 extending in the opposite direction
from
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that shown, to the front side of the joist web 38 with the joist 24 in the
orientation shown, or to the front side of the joist web 38 with the joist
legs 40,
42 extending in the opposite direction from that shown. For ease of
installation
the bottom edge of the clip 26 may rest on the rim track bottom leg 32 or the
joist bottom leg 42. Fasteners 48 such as screws or other anchors may be
used to fasten the joist 24 to the rim track 22 via the clip 26.
Another prior art rim track and joist assembly 50 is shown in FIG. 2. The
assembly 50 includes a rim track 52 and a joist 54 mounted to the rim track
52.
The rim track 52 is C-shaped and includes a central web 58, an upper leg 60
that extends perpendicularly from the top edge of the web 58, and a lower leg
62 that extends perpendicularly from the bottom edge of the web 58 in the
same direction as the upper leg 60. There are openings 63 made through the
web 58 to form tabs 64, which are integral with the web 58 and are bent at a
90
degree angle to the web 58. Uses for such integral tabs 64 may include joist
attachment. Integral joist attachment tabs 64 may include holes 66 for
fasteners 68. Rib stiffeners 69 are provided. The rim track 52 rests on top of
a
wall 70, and may be fastened to the wall 70 periodically with fasteners 72,
such
as screws or other anchors, through the lower leg 62. The wall 70 may be, for
example, block, concrete, or steel or wood framing.
The joist 54 is also C-shaped and includes a central web 74, an upper
leg 76 that extends perpendicularly from the top edge of the web 74, and a
lower leg 78 that extends perpendicularly from the bottom edge of the web 74
in
the same direction as the upper leg 76. The joist 54 is mounted to the rim
track
52 with the integral joist attachment tab 64. The integral joist attachment
tab 64
is shown to be attached to the back side of the joist 54. Other similarly
formed
tabs, not used for joist attachment, could be provided.
FIG. 3 shows a rim track and joist assembly 80 in accordance with an
embodiment of the present invention. The assembly 80 includes a rim track 82,
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a joist 84, and a clip 86 that is used to mount the joist 84 to the rim track
82.
The rim track 82 is C-shaped and includes a central web 88, an upper leg 90
that extends perpendicularly from the top edge of the web 88, and a lower leg
92 that extends perpendicularly from the bottom edge of the web 88 in the
same direction as the upper leg 90. There are longitudinally spaced, vertical
slots 94 in the web 88. The rim track 82 rests on top of a wall 96, and may be
fastened to the wall 96 periodically with fasteners 98 through the lower leg
92.
The joist 84 is also C-shaped and includes a central web 100, an upper
leg 102 that extends perpendicularly from the top edge of the web 100, and a
lower leg 104 that extends perpendicularly from the bottom edge of the web 100
in the same direction as the upper leg 102. The joist shown has a vertical lip
106, 108 running along each leg 102, 104, and generally has a closed web 100,
except where there may be penetrations. Instead of the closed-web joist 84 as
shown, a joist that is an open web truss could be provided, so long as it has
a
solid end piece to allow attachment to the clip 86. The joist 84 is mounted to
the rim track 82 with the clip 86, which has two arms 110, 112. One arm 110 of
the clip 86 is fastened to the back side of the web 88 of the rim track 82,
and
the other arm 112 of the clip 86 extends through the slot 94 and is fastened
to
the front side of the joist web 100. Alternatively, the arm 112 attached to
the
joist 84 could be attached to the front side of the web 100 with the joist
legs
102, 104 extending in the opposite direction from that shown, to the back side
of the joist web 100 with the joist 84 in the orientation shown, or to the
back side
of the web 100 with the joist legs 102, 104 extending in the opposite
direction
from that shown. The interior face of the arm 110 that is attached to the rim
track web 88, which is the face of the clip 86 proximate to the interior angle
formed by the two arms 110, 112, abuts the back side of the rim track web 88.
As a further alternative configuration, joists 84 could be attached to the
backside of the rim track web 88. Such a configuration would equate to the
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assembly of FIG. 3, for example, with the top web 90 and bottom web 92
extending in the opposite direction from that shown.
Fastening of clips 86 to the rim track 82 and joists 84 may be done with
fasteners 114 such as screws, which may be self-tapping, bolts, pneumatic
pins, or other means known to one of ordinary skill in the art. The clips may
be
pre-punched or pre-drilled if necessary or desired based on the anchor type.
Pneumatic pins may expedite installation and assembly time, and specific pins
may be selected by one of ordinary skill in the art. Pneumatic pins generally
have a pointed end, a head, and a knurled shaft with spiral grooves. The force
lo delivered by a pneumatic tool causes the pin to penetrate the steel, and
the
steel is forced outward to create a hole. The steel contracts around the pin,
which is held in place by the grooves. Although three fasteners 114 are shown
in FIG. 3, the number may vary depending on the design and application as
determined by one of ordinary skill in the art.
The vertical slots 94 in the rim track 82 may be, in one embodiment,
longitudinally spaced along the rim track 82 at 8-inch intervals. This allows
joist
attachments at 8, 16, and 24-inch intervals (or other multiples of 8 inches)
in
accordance with conventional practice. No marking of the spacing and location
for the clips 86 is required, as the slots 94 automatically locate the joists
84.
The following dimensions and gauges are all exemplary and may vary with the
design and as selected by one of ordinary skill in the art. Dimensions of the
slots 94 may be, for example, about 8 inches in height and 1/4 inch in width,
centered on a 16 gauge (0.0635 inches) thick rim track 82 with a 12-1/4 inch
depth. The legs 60, 62 of the rim track 82 may extend 1-114 inches from the
web 88. The joist 84 may be 16 gauge, have a 12 inch depth, have legs 102,
104 that extend 1-5/8 inch from the joist web 100, and have 1/2 inch lips 106,
108. The clips 86 may also be 16 gauge, may have a length of about 8 inches,
and may have arms 110, 112 that are 2-1/2 inches.
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The slots 94 may be punched in the rim track web 88. While there may
be some deformed material around the edge of the slot 94, in general and
depending on the equipment used it may be expected that this deformed
material will protrude no more than about 1/2 inch from the web 88, and there
may be no detectable deformation at all or the deformation may not be readily
ascertainable to the eye. Accordingly, the edges of the slots 94 may be
substantially flush with the planar profile of the rim track web 88. To allow
the
clips 86 to be flush with the back of the rim track web 88, the slots 94 may
be
punched from the back side to the front side to cause the deformation to be on
1 o the front side of the rim track web 88. The centered position of the slots
94 on
the rim track web 88 allows for ease of centering the clips 86; in the
conventional installation of FIG. 1, the clip 86 may rest on the top surface
of the
rim track bottom leg 92, and centering the clip 86 on the web 88 would require
additional effort.
FIG. 4 shows a portion of a rim track embodiment in accordance with the
present invention. When the back of the rim track 82 is accessible, the arm
112
of the clip 86 that will be connected to the joist 84 may be inserted 130
directly
through the slot 94. FIG. 5 shows one way to insert the clip 86 when the back
of the rim track 82 is not accessible. The arm 110 of the clip 86 that will be
2o attached to the rim track 82 is inserted 132 through the slot 94, and then
the clip
86 is rotated 134 so that that arm 110 abuts the back side of the rim track
web
88. Alternatively, the clip 86 may be inserted in advance of placement of the
rim track 82 such that the back of the rim track 82 is accessible for
installation
of the clip 86.
FIG. 6 shows a floor 140 and floor support system 142. The system 142
includes two rim tracks 82 supported by two walls 96. Although the walls 96
are
shown as solid, they may be a variety of types as previously discussed. Joists
84 span between the rim tracks 82 and are mounted to the rim tracks 82 at
each end with clips 86. The clips 86 in this embodiment are angles and extend
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through the vertical slots 94 in the rim tracks 82. Each clip 86 has one arm
110
fastened to the back of the rim track web 88 and the other arm 112 fastened to
the front of the joist web 100, as in FIG. 2, with fasteners 78. Also as
previously
discussed, the orientation of the joist 84 and the side of attachment of the
clip
86 relative to the joist 84 may vary as determined by one of ordinary skill in
the
art. The joists 84 may include large penetrations 144 for elements such as
ductwork and plumbing, and smaller penetrations 146 for elements such as
electrical conduit and wiring. Small holes (not shown) may be provided to
accommodate wire brackets for holding insulation in place. Blocking members
lo 148 may be provided between the joists 84 for lateral stability.
Instead of being a C-shaped joist 84, the joist could be Z-shaped or a
tube (a hollow rectangular section). In addition, rather than being L-shaped,
the
clips could be T-shaped. As shown in FIG. 7, with a T-shaped clip 150 there
would be three arms 152, 154, 156 with two arms 152, 154 extending 180
degrees from each other and the third arm 156 at a 90 degree angle to each of
the other arms 152, 154. The linearly aligned arms 152, 154 would be fastened
to the back of the rim track 82. If desired to accommodate other angular
alignments of rim tracks and joist, the angles of either two-armed or three-
armed clips could vary from 90 degrees.
Specific embodiments of an invention are described herein. One of
ordinary skill in the art of structural building design will recognize that
the
invention has other applications in other environments. In fact, many
embodiments and implementations are possible. For example, the present
invention could be applied to different structural members, other than for
support of loads other than building floors, and for materials other than
steel. In
addition, the recitation "means for" is intended to evoke a means-plus-
function
reading of an element in a claim, whereas, any elements that do not
specifically
use the recitation "means for," are not intended to be read as means-plus-
function elements, even if they otherwise include the word "means." The
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following claims are in no way intended to limit the scope of the invention to
the
specific embodiments described.
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