U.S. patent application number 11/020242 was filed with the patent office on 2006-07-13 for floor system with stell joists having openings with edge reinforcements and method.
This patent application is currently assigned to GCG Holdings Ltd. Invention is credited to Ernest R. Bodnar.
Application Number | 20060150548 11/020242 |
Document ID | / |
Family ID | 36614429 |
Filed Date | 2006-07-13 |
United States Patent
Application |
20060150548 |
Kind Code |
A1 |
Bodnar; Ernest R. |
July 13, 2006 |
Floor system with stell joists having openings with edge
reinforcements and method
Abstract
A steel joist member for use in supporting floor structures
giving great strength and convenience and improved acoustical
performance having a web defining side edges and an axis, a flange
on at least one side edge, openings through said web at spaced
intervals therealong, having rounded ends and parallel linear
sides, portions of said web displaced from said opening remaining
attached integrally to the web by bend lines formed on the linear
sides of the opening along axes parallel to the web axis, and
forming reinforcing channels alongside the opposite sides of the
opening. Also disclosed is a composite joist member made up of two
such members joined together back to back with their openings in
registration creating an H shape or an I shape. Also disclosed is a
rim member for supporting the composite joists to form a floor
structure. Also disclosed is a method of making such a floor joist
member. Also disclosed is a floor panel system wherein floor panels
can be prefabricated in a factory and transported to a construction
site ready for installation in a building.
Inventors: |
Bodnar; Ernest R.;
(Burlington Ontario, CA) |
Correspondence
Address: |
George A. Rolston
Suite 900
45 Sheppard Avenue East
Toronto
ON
M2N 5W9
CA
|
Assignee: |
GCG Holdings Ltd
|
Family ID: |
36614429 |
Appl. No.: |
11/020242 |
Filed: |
December 27, 2004 |
Current U.S.
Class: |
52/262 |
Current CPC
Class: |
E04C 3/09 20130101; E04C
2003/0482 20130101; E04B 5/10 20130101; E04C 2003/0452 20130101;
E04C 2003/0413 20130101; E04C 2003/0434 20130101; E04C 2003/0473
20130101; E04C 2003/0421 20130101 |
Class at
Publication: |
052/262 |
International
Class: |
E04B 5/00 20060101
E04B005/00 |
Claims
1. A steel joist member for use in floor structures and having
reduced weight, and improved acoustical performance characteristics
as compared with solid web steel joists, and comprising; a web
defining side edges and an axis; a flange on at least one side
edge; openings through said web at spaced intervals therealong, of
generally elongated oval shape, and defining curved ends and
opposed linear sides; edge flanges extending around said opening
substantially at right angles thereto; two bracing lip portions of
said web being displaced from said opening and remaining attached
integrally by edge flanges to said web along opposite linear sides
of said opening; a right angle bend in each said lip portion bent
parallel to but displaced away from said web, thereby forming said
lip portions into channel shapes in section for strengthening said
joist in the regions of said openings.
2. A steel joist member as claimed in claim 1 including depressions
formed in said web at spaced intervals, and openings formed in said
depressions to reduce sound transfer through the joist.
3. A steel joist member as claimed in claim 1 wherein there are two
said flanges one on each side of said web, being formed normal to
said web, and lips formed along said flanges normal to said
flanges.
4. A steel joist member as claimed in claim 1 said openings are
identical and symmetrical, and are arranged in uniform aligned
orientation and define between them transverse struts extending
transversely across said web.
5. A steel joist member as claimed in claim 4 including openings
formed in said web at opposite ends of each said strut.
6. A steel joist member as claimed in claim 5 including an
embedment flange formed on a said edge flange on said one side of
said web whereby to permit embedment in a concrete panel.
7. A composite joist member formed of two steel joist members as
claimed in claim 1, said two joist members being arranged back to
back with their respective flanges extending away from one another,
and with their openings registering with one another to form a
composite joist member
8. A steel joist as claimed in claim 1 for partial embedment in
concrete and including an angled flange formed with openings for
flow of concrete therethrough, and a locking strip formed along
said angled flange.
9. A floor system for supporting a floor and comprising; a
plurality of composite steel joist member made up of two steel
joists each said steel joist in turn comprising; a web defining
side edges and an axis; a side flange on at least one side edge;
openings through said web at spaced intervals therealong, each said
opening being of generally elongated oval shape, and defining
curved ends and opposed linear sides; edge flanges extending around
each said opening substantially at right angles thereto; two
bracing lip portions of said web being displaced from said opening
and remaining attached integrally by edge flanges to said web along
opposite linear sides of said opening; a right angle bend in each
said lip portion bent parallel to but displaced away from said web,
thereby forming said lip portions into channel shapes in section
for strengthening said joist in the regions of said openings; at
least two rim members, each said rim member in turn comprising; a
web, and a support flange extending from said web at right angles;
a top flange for engaging a wall structure; a plurality of tabs
displaced from said web, for attachment to respective said
composite joist members.
10. A floor system for supporting a floor as claimed in claim 9
wherein said composite joist members are formed with embedment
flanges and locking strips along one of their sides, and wherein a
portion of said embedment flanges and locking strips are removed
adjacent said tabs, to facilitate interconnection with said
tabs.
11. A floor system for supporting a floor as claimed in claim 9
wherein said rim member is formed with abutments for engaging sides
of said composite joist members.
12. A floor system for supporting a floor as claimed in claim 9
wherein said rim members incorporate an upstanding edge flange.
13. A floor system for supporting a floor as claimed in claim 9
wherein said rim members incorporate an downward edge flange.
14. A floor system for supporting a floor as claimed in claim 9
wherein said top flanges of said rim members incorporate upstanding
embedment loops.
15. A floor system for supporting a floor as claimed in claim 9
wherein said joist members and said rim members are assembled into
a prefabricated panel ready for delivery to a building site.
16. A floor system as claimed in claim 15 and including an
embedment flange formed on a said edge flange on said one side of
said web whereby to permit embedment in a concrete panel, and a
concrete slab poured and set embedding said embedment flanges.
17. A method of making a composite steel joist member formed of two
steel joists each having a web and side edges, and a flange along
at least one said side edge, and openings through said web, said
method characterized by the steps of; forming said openings which
are identical and symmetrical spaced along said web at spaced
intervals therealong, with portions of said web being displaced to
one side of said opening leaving two side portions attached to said
web, and, forming said side portions by bending said side portions
along bend lines parallel to the web axis, to define channel shapes
in section, and arranging said two joists back to back with their
openings in registration with one another.
18. A method of making a composite steel joist member as claimed in
claim 17 and including the step of forming struts extending
transversely across said web between said openings and forming
openings in said web adjacent each end of each strut.
Description
FIELD OF THE INVENTION
[0001] The invention relates to a floor system having steel joists
and rim members supporting the joists, the joists and rim members
being formed with openings, and having edge reinforcements formed
around the openings. In particular the openings in the joists are
formed with linear reinforcement channel formations along opposite
sides of the openings, which are formed with bends at respective
first and second angles with respect to the plane of the joist.
BACKGROUND OF THE INVENTION
[0002] Steel joists of a wide variety have been proposed for
erecting floor structures.
[0003] Usually such joists are used to replace wooden joists. Metal
joists having solid webs have been used but interfere with the
space between the floor and the ceiling beneath. Such joists
usually were formed as a C-section, ie there was a central web, and
the opposite side edges of the web were formed into edge flanges.
Several such bends were sometime incorporated in an effort to get
greater strength, while using thinner gauge metal. Services such as
plumbing wiring and HVAC were obstructed by such joists Accordingly
metal joists have been proposed formed with openings, usually
generally triangular or trapezoidal openings, in the web, while the
two edges were formed with bends, as before.
[0004] These openings were positioned so as to define diagonal
struts extending across the joists. In this way it was hoped to
achieve strength while reducing weight and obstruction. However
because the openings in the metal joists were of these specialized
generally triangular or trapezoidal shapes, the services, in many
cases conduits of substantial diameter, could not fit through the
openings. It was not possible for the builder to cut away any of
the diagonal struts to provide larger openings for services, since
this would drastically reduce the strength of the joists.
[0005] The shape of these openings tended to restrict the size of
the conduits which could be passed through the joists.
[0006] Another problem arose in that the triangular openings were
formed with edge flanges around their perimeter. Where these edge
flanges extended around an angular corner of the opening there was
a tendency for the sheet metal to crack. Consequently the corners
had to be radiussed or rounded out. This meant that there was more
metal at each of the corners, and the size of the openings was
reduced. Another problem arose in cutting these joists to length.
The openings were arranged in pairs with one triangle facing one
way and the next triangle facing the opposite way. Cutting such
joists to length requires that all of the openings of a particular
orientation, in all of the adjacent joists in a floor, shall line
up. This required to facilitate passing of services through the
joists. However due to the alternating orientation of the openings,
this requirement resulted in cutting off end portions of joists
equal in length to the space occupied by two of the openings, in
many cases. Forming such joists with alternating triangular
openings, requires that the openings be formed repeatedly along the
joist. However at each end, the joist web must be solid and free of
openings.
[0007] This required specialized machines which could "miss" one or
more openings, leaving a length of web, solid, and available for
cutting to length.
[0008] Another factor is that concrete is in wide use for pouring a
floor slab.
[0009] Usually the slab was simply supported on top of the joists.
It is now found that when portions of the metal joists are
partially embedded in the concrete, they provide much greater
strength to the slabs. Slabs can thus be thinner than in the past,
saving material, time, and weight.
[0010] It has now been surprisingly found that the use of the
specialized triangular or trapezoidal shapes of these joist
openings, is unnecessary.
[0011] Reduction in weight is possible, by the use of the
invention, using regular symmetrical generally oval-shaped
openings, with end portions of the opening being defined by a
semi-circular radius. The remainder of the opening is defined by
opposite parallel linear edges.
[0012] The resulting openings are thus of a somewhat extended oval
shape, with linear sides. Solid portions of the web remain, between
adjacent openings and form struts extending transversely from one
edge to the other of the web. This avoids the diagonal struts of
earlier joists. This also means that the size of the conduits
passed through the openings can be increased. The openings
substantially span the distance across the web, between the edge
flanges of the joist. By the use of the invention it is now
possible to form openings which can accept conduits having a
diameter equal to the distance across the web opening between the
edge flanges of the joist.
[0013] This is a great improvement over the earlier triangular
opening and diagonal strut configuration.
[0014] Openings with semi-circular or radiussed ends avoid the
problems caused by the corners of the triangular or trapezoidal
openings and splitting of metal, and results in a much stronger
joist. The use of openings with semi-circular ends greatly
facilitates high speed manufacture of such joists. The openings are
of identical footprint along the web. This means that cutting to
length becomes possible at shorter intervals, and there is less
joist length lost in the process. The joists with such openings
define service pathways for cylindrical service conduits. In each
joist the conduit diameter can be equivalent to the distance across
the joist between one side edge of the opening and the other,
transversely across the joist. This means that the conduits can
pass through any opening in the joist, regardless of the
orientation of the opening in the joist.
[0015] This greatly reduces wastage of sheet metal during
manufacture.
[0016] Much larger conduits can be accepted.
[0017] Another factor is earlier designs was the thought that it
was essential to remove as much metal as possible. This was
considered desirable to improve acoustical performance and avoid
transmission of sound from one floor to the next.
[0018] It has now been found that this was incorrect. What is
required is a joist with openings which leave larger openings and
more symmetrical openings without loss of strength. It has also now
been found that the opposite parallel linear edges of each opening
can be greatly strengthened by removing less sheet metal at each
opening, rather than more. This surprising development results in
leaving an additional piece of sheet metal along side each of the
linear edges. These additional pieces are formed, in accordance
with the invention, into two generally right angular bends,
resulting in two additional channel structures along the opposite
linear sides of each opening in the joist. Preferably both bends
are formed essentially as right angular bends. This greatly
increases the strength of the joist in the critical area of the
extended linear edges of each opening. The fact that more metal
remains in the joist does not cause problems, since the extra
metal, which is not removed, is simply displaced in a location
alongside the opening.
[0019] The blanks of sheet metal removed in this process, are of a
size and shape which leads to economies in the process since the
blanks are smaller. Slug ejection problems in the manufacturing
machinery are reduced and there is less wastage of metal.
[0020] The semi-circular ends of the openings reduce the problems
for the builder who wishes to pass service conduits through the
joists within the floor. Much larger diameter pipes can now be fed
through the joists, than was possible before. This leads to less
sales resistance due to a greater acceptance of the product in the
market place.
[0021] The shape of the openings is symmetrical and identical. This
makes it possible to align the joists in pairs back to back to make
stronger composite joists while still maintaining the full size of
the openings through the joists, for passing services.
[0022] These features can be used in joists having special
embedment edge formations for embedment in concrete.
[0023] The features can also be used in forming much heavier duty
joists with the edge formations formed into a triangular tube
shape.
[0024] Two such joists can be secured back to back to greatly
increase the load bearing capacity.
[0025] Such joists enable to formation of a floor system with rim
members located on a wall structure, and with the joists extending
across the space between opposite rime members.
[0026] The rim members will also be formed with openings of the
type described above.
[0027] Such rim members will also provide support flanges for
supporting opposite ends of the joists. Where a concrete slab floor
is to be poured such rim members will incorporate embedment
formations for embedment in the slab.
[0028] Fastening tabs extend from the rim members, for fastening to
the ends of the joists. Abutments may be formed on the rim members
to engage opposite sides of the web of each joist to give greater
strength.
[0029] It will be appreciated that a joist which improves on all
these problems associated with prior joists, will have application
in general use, for many various construction applications. In
particular however it will have advantages in the construction of
floors with joists acting as reinforcement for thin-shell concrete
slabs.
[0030] Such joists can also be used to form floors having a panel
surface such as plywood panels.
[0031] The joists and rim members may be associated together in
accordance with the method described. Preferably the assembly of
the rim members and joists, and also the pouring of concrete in
some cases, will be done in a factory away from the building site.
The floor can be prefabricated in sections. When transported to the
site the sections or panels will simply be lifted into place and
fastened together to form the complete floor in the building.
BRIEF SUMMARY OF THE INVENTION
[0032] With a view to achieving the foregoing and other objectives
the invention comprises steel joist members, for use in floor
system, and having a web defining side edges and an axis, a edge
flange on at least one side edge of the web, identical symmetrical
openings formed through said web at spaced intervals therealong, of
predetermined size and profile, with rounded ends and linear sides
parallel to one another, side portions of said web displaced from
said opening remaining attached integrally to said web along
opposite linear sides of the opening, a first bend formed in each
said side portion, a second bend formed in each said side portion
parallel to and spaced from said first bend, said first and second
bends being formed along axes parallel to said web axis. The
invention further seeks to provide a steel joist member as
described including depressions formed in said web at spaced
intervals, and openings formed in said depressions to increase
strength and to provide some reduction in heat transfer.
[0033] The invention further seeks to provide a steel joist member
as described wherein said displaced side portions define respective
channel shapes extending along axes parallel to said web axis.
[0034] The invention further seeks to provide a steel joist member
as described wherein said openings are of a shape defining opposite
parallel linear side edges, and arcuate end edges, said side
portions of said web being integral with said linear side edges,
and continuous edge flanges formed all around said openings.
[0035] The invention also provides a composite joist member formed
of two steel joists as described being attached back to back to one
another to form a composite joist member. In this embodiment
because the shape of the openings is symmetrical and identical,
composite joists can be made simply by placing two joists back to
back with their openings in registration with one another. Such
composite joists have great strength, while still permitting the
passing of services.
[0036] The invention also provides a rim member for attachment on a
structure around a floor, and supports on said rim member for
supporting opposite ends of each steel joist member.
[0037] The rim member may also incorporate fastening tabs for
fastening to each steel joist member.
[0038] The rim member may also incorporate embedment formations,
and also joist end abutments.
[0039] The invention also provides a method of making a steel joist
member having a web and side edges, and a flange along at least one
said side edge, and openings through said web, said method
comprising the steps of, forming openings having opposed linear
parallel sides and arcuate ends in said web at spaced intervals
therealong, leaving side portions of metal attached to said web
along each of said opposed linear sides, forming said edge flange
along said at least one side edge of said web, and, forming said
side portions out of the plane of said web by bending each said
side portion along a first bend line and then along a second bend
line spaced from and parallel to said first bend line.
[0040] The invention also provides a method of forming a floor
joist system, using rim members and steel joist members described
above.
[0041] The various features of novelty which characterize the
invention are pointed out with more particularity in the claims
annexed to and forming a part of this disclosure. For a better
understanding of the invention, its operating advantages and
specific objects attained by its use, reference should be made to
the accompanying drawings and descriptive matter in which there are
illustrated and described preferred embodiments of the
invention.
IN THE DRAWINGS
[0042] FIG. 1 is a perspective illustration of a floor system
illustrating one embodiment of the invention, having composite
joists formed of two steel joist members in which the openings have
opposite linear sides and semi-circular or arcuate ends, and
channels formed on said opposite linear sides of the openings;
[0043] FIG. 2 is a section of one joist member along line 2-2 of
FIG. 1;
[0044] FIG. 3 is a section of one joist member along line 3-3 of
FIG. 1;
[0045] FIG. 4 is a side elevation of a portion of one joist member
of FIG. 1, with parts shown in section;
[0046] FIG. 5 section of one joist member along line 5-5 of FIG.
1;
[0047] FIG. 6 is a perspective of a rim member from the embodiment
of FIG. 1;
[0048] FIG. 7 is a section of a rim member along line 7-7 of FIG.
6;
[0049] FIG. 8 is a section of a rim member along line 8-8 of FIG.
6;
[0050] FIG. 9 is a section of a rim member along line 9-9 of FIG.
6;
[0051] FIG. 10 is a perspective of a further embodiment of floor
system using composite joist members illustrating another
embodiment of the invention, in which the rim member is modified
from FIG. 1;
[0052] FIG. 11 is a perspective of a further embodiment of floor
system illustrating another embodiment of the invention, for
supporting a panel floor typically of plywood, with the composite
joist members modified to remove the embedment edges;
[0053] FIG. 12 is a perspective of a further embodiment of floor
system illustrating another embodiment of the invention, for
supporting a panel floor typically of plywood, with the rim member
modified from FIG. 11;
[0054] FIG. 13 is a perspective of a further embodiment of floor
system using composite joist members illustrating another
embodiment of the invention, in which the rim members are supported
on the edge of a wall frame formed of metal studs;
[0055] FIG. 14 is a perspective of a further embodiment of floor
system using single joist members illustrating another embodiment
of the invention;
[0056] FIG. 15 is a perspective of a further embodiment of floor
system using composite joist members illustrating another
embodiment of rim member in which the flange is of reduced width
compared to FIG. 1.
DESCRIPTION OF A SPECIFIC EMBODIMENT
[0057] As already described the invention provides a floor system
using sheet metal joists, having improved acoustical performance to
reduce transmission of sounds from one floor to the next. The
joists are suitable for use in erecting floors, or roofs, and the
like. The invention also provides sheet metal joists suitable for
use in reinforcement of slab concrete panel floors or roofs.
[0058] The invention also provides composite H shaped or I shaped
joist members formed by joining two joist lengths together back to
back, and a method of making such a joist member, and a method of
forming a floor.
[0059] For the purposes of this description the word "floor" is
used to describe a level structure used in construction, which may
function either as a floor for supporting persons and objects
within a structure, or to a roof for enclosing a structure. When
used as a roof, such a structure will usually have a slope, whereas
when used as a floor it will be level. The invention is equally
applicable to either function.
[0060] Referring to FIG. 1 it will be seen that the invention is
there illustrated in the form of a floor (10). Typically the floor
(10) made up of composite sheet metal joist members (12), and rim
members (14). Typically the rim members (14) are supported on the
upper edge of a wall, not shown, or a basement or other structure.
The joist members (12), span the space surrounded by the rim
members (14), and the joist members (12) are supported at their
ends on the rim members (14)
[0061] As shown in FIG. 1 the composite joist members (12) in this
embodiment are composites made up of two identical joists (20),
placed back to back. In this way the composite joist member forms
an H shape or I shape member. Each joist (20) is formed of sheet
metal, in this case steel. Each joist (20) has a web (22) which is
essentially planar, and an edge flange (24) along the lower side
edge of the web (22). Edge flange (24) is formed by bending the web
at right angles. A lip (26) are formed on the edge flange (24)
again at right angles. In the web (22) openings (28) are formed by
punching out a portion of the sheet metal, and by displacing but
not removing other portions of sheet metal as will become apparent
below.
[0062] In this embodiment the openings (28) are formed in a
generally oval shape elongated along the length of the joist (20).
The openings are identical and symmetrical for reason to be
described. Each opening (28) has opposite ends (30) located along
the central axis of the web (22) with a semi-circular or arcuate
profile.
[0063] Between the ends (30) along opposite sides, the openings
(28) are formed with elongated linear parallel sides as at
(32).
[0064] Elongated transverse ribs (34) may be formed if desired, at
the ends of the joists, (FIG. 2 and 3), to provide greater rigidity
at the joist ends for reasons described below.
[0065] Extending all around opening (28) there is an edge flange
(36) formed at right angles to the web (22). Along the two linear
sides (32) of the opening there is are bracing lips (38) formed,
extending integrally from the edge flanges (36). Lips (38) is
formed by portions of the web (22) which have been partly punched
out and displaced, but which remain joined as part of the edge
flanges (36), along such linear sides of the opening (28). Bracing
lips (38) are formed at a right angle bend (40) parallel to but
spaced from the plane of the web (22). In this way two bracing lips
(38) forms short channel shape reinforcements extending from the
edge flanges (36), along the two linear sides (32) of the opening
(28). In this way lips (38) greatly reinforce the joist (20) along
the length of the two linear sides (32) of opening (28).
[0066] This feature permits the openings (28) to be formed with
relatively large dimensions, so that a conduit, not shown, can
extend through opening (28) and is limited only by the transverse
dimension of the opening transversely across the web (22). This is
a great improvement over joists having triangular openings. A
junction flange (42) is formed along the upper side of the web
(22), for reasons described below.
[0067] It will be noted that the shape and placement of the
openings (28) defines struts (44) extending transversely across the
web (22). Such struts reduce the transfer of sounds across the
joist. Joists (20) are further formed with depressions (46) at
opposite ends of each strut (44) where the strut flares out into
the web (22). Centered in such depressions (46) there are punched
out openings (48), which in this case are circular, although they
could be other shapes. The openings (48) remove metal and this
provides a better barrier to conduction of sound across the joist
and improve its acoustical performance. This embodiment of joist is
particularly advantageous. It has great strength due to the
retention of a considerable amount of the metal displaced by
blanking the openings (28). A large part of such metal is not
removed but is retained and is folded over outwardly to form the
channel shaped bracing lips (38) forming both sides of the opening
(28).
[0068] FIGS. 1 to 6 illustrate another feature of joist (20) for
embedment in a concrete slab.
[0069] Junction flanges (42) are formed with embedment edge flanges
(50) which are bent out of the plane of the web by about 45
degrees. The angle can vary somewhat for various applications.
[0070] Flanges (50) are bent outwardly, and are formed with a
series of openings or ports (52) for concrete flow.
[0071] A return lip (54) is formed along flange (50) for embedment
in concrete Thus this embodiment provides a joist of great strength
providing reinforcement for a concrete floor slab or panel. The
flanges (50) being partially embedded in concrete will provide
maximum security of adhesion between the joists and the
concrete.
[0072] This joist may enable the use of a reduction in thickness of
sheet metal. It is anticipated that a reduction of at least one
gauge and probably two gauges can be achieved while still providing
adequate support to a concrete floor slab or panel.
[0073] This will reduce the cost of the floor slabs or panels.
[0074] FIG. 9 shows a further form of joist (100) having features
which make it suitable for supporting floors made of other panel
materials, such as plywood or the like. Joist (100) has a web (102)
and identical side flanges (104) and (106) along either side of the
web. Lower and upper edge flanges (104) and (106) are identical and
are bent at a right angle to the plane of the web. Integral edge
lips (108) extend from flanges (104) and (106) parallel to the
plane of the web.
[0075] Ribs (110) are formed as before transversely of the joists
(100)
[0076] Openings (112) are formed through web (102) as before, being
of generally elongated oval shape in the FIG. 1 embodiment.
[0077] Edge rims or flanges (114) are formed therearound as before.
Linear side edges (116) and (118) of opening (112) are reinforced
by bracing lips (120) of sheet metal, extending integrally from web
(102), thus retaining more of the metal displaced by forming the
opening (112) and employing it to improve the joist, rather than
discarding it as waste.
[0078] Lips (120) are folded into right angular channels extending
along each linear side of opening (112), to provide greater
strength. More metal is retained in the joist, which both increases
its strength, or in the alternative permits a reduction in gauge.
Depressions, (122) with openings (124) which may be circular or
other shapes are formed in the web, as described above to aid in
reducing heat losses.
[0079] In use two such joists (20) or (100) are juxtaposed as shown
in FIG. 1 and 9, in back to back relation. They may be secured
together, if desired, by eg spot welds or the like (not shown) to
form a composite joist member.
[0080] Manufacture of the joists (20) or (100) can proceed by first
forming the openings (112) and rim flanges (114) in a suitable
press. This can be a flying die press, but it is advantageous to
use a rotary press of the type which has two rotary die support
rolls, and dies on the support rolls, in which the two support
rolls rotate bringing the dies together and apart as the sheet
metal moves between them. After blanking and forming of the
openings and forming of the edge flanges around the openings, and
the forming of the depressions and punching of the depression
openings, the semi-formed sheet metal is then passed through a
series of roller die stands, such as are known per se and require
no description. The roller dies on the die stands will
progressively form the edge flanges (24) or (104,106) and the
bracing lips (38) or (120) on either side of the openings.
[0081] Cutting to length may be performed upstream of the rotary
press where the strip sheet is still flat and unformed. In this way
each piece of sheet metal passing through the various punching and
forming and roll forming sequences is already precut to the exact
length required for the finished joist.
[0082] It also possible to cut the joists to length downstream of
the roller dies, depending on the design of the equipment.
[0083] It must be remembered that in cutting to length, provision
must be left at each end of each joist to leave end portions of the
joist free of openings, so that in can be supported in place in an
eventual floor structure, with all of the openings in each joist
aligned with one another across the structure. In the case of
joists (20) and (100) this is greatly facilitated by the fact that
the openings (28) and (112) are identical and symmetrical and are
separated by transverse ribs Cutting to length is rendered easier
by this form of joist. When the two joists are placed back to back,
with the openings in registration with each other, it will be
apparent that this will greatly facilitate the installation of
services through the openings.
[0084] In order to assemble the composite joist members (12) into a
floor, a rim member (14) is provided, as shown in more detail in
FIG. 11 and 12.
[0085] The rim member (14) has a web (130) and a top flange (132)
extending at right angles.
[0086] Flange (132) is intended to lie on top of a wall or basement
structure.
[0087] Flange (132) may have an upstanding edge wall (134), or an
downwardly bent edge wall (136) turned down to lock on to the
outside of a wall.
[0088] Along the lower edge of web (130) a support flange (138)
extends at right angles, to support the ends of the composite joist
members (12).
[0089] In order to secure the joist member in position, tabs (140)
are struck out of web (130) and extend in parallel spaced relation
over support flange (138). In the embodiment shown the tabs (140)
are located in the same plane as the flange (132). In this way the
upper horizontal surfaces of junction flanges (42 of the joist
members (12) will lie coplanar with the flange (132). In the case
of the embodiment of FIG. 1 the embedment edges (50) of the joist
members will extend above such a plane, and this is intended so
that a concrete floor slab may be poured which extends over flanges
(132) of rim member (14).
[0090] When the joist members (12) are to be attached to the tabs
(140) a short portion of the embedment flange will be removed at
the ends of the joist members (12)2 This will enable the junction
flanges (42) to fit beneath the tabs (140) and secured thereto by
fasteners. Fasteners will also be used to secure the edge flange
(24) to the support flange (138) of the rim member (14).
[0091] In the case of a poured concrete floor, the flange (132) of
the rim member (14) is formed with embedment loops (142) struck out
of the flange. The poured concrete will flow around such loops
(142) and will thus secure the rim member (14) in position.
[0092] In the case of a panel floor, of plywood for example, the
flange (132) of the rim member (14) is formed flat, without any
such loops. This enables such a panel floor to be laid flat on the
upper flanges (106) of joists (100), and then to lie flat on the
flanges (132) of the rim member (14).
[0093] Since in this case the upper flange (106) is planar, it will
fit beneath the tabs (140) without requiring the removal of any
portion.
[0094] It will be understood that in many cases there may be only
two such rim members (14), parallel and spaced apart on opposite
walls for supporting joist members (12) spanning the area. For
additional stiffness, if desired, abutments (144) may be formed in
the web (130). These abutments are spaced apart so as to engage the
opposite sides of the composite joist members, at each end.
[0095] The webs (130) are also formed with generally oval shaped
openings (146) similar to the joists, and edge flanges (14*0 and
lips (15) are formed therearound as before.
[0096] Vertical ribs (152) are formed in web (130) for adding
stiffness.
[0097] In this case single joists (20) or (100) (FIG. 1 and FIG. 6)
alongside the extreme edges of the floor may themselves lie on top
of the wall.
[0098] In other cases there may be four such rim members (14), or
even more, depending on the area to be enclosed by a floor.
[0099] Intermediate rim members (14) supported above a floor by any
suitable means may be required to span a greater area, of the cover
in a space of a special shape in plan.
[0100] The joists and rim members may be associated together in
accordance with the method described. Preferably the assembly of
the rim members and joists, and also the pouring of concrete in
some cases, will be done in a factory away from the building site.
The floor can be prefabricated in sections. When transported to the
site the floor sections or panels will simply be lifted into place
and fastened together to form the complete floor in the
building.
[0101] Various embodiments are proposed, with variations for
different applications.
[0102] Thus FIG. 10 is a perspective of a further embodiment of
floor system using composite joist members illustrating another
embodiment of the invention, in which the rim member is modified
from FIG. 1. In this case the edge flange (136) is shown turned
down.
[0103] FIG. 11 is a perspective of a further embodiment of floor
system illustrating another embodiment of the invention, for
supporting a panel floor typically of plywood, with the composite
joist members modified to remove the embedment edges. In this case
the composite joist members are the same as in FIG. 1 but the
embedment edges are removed and replaced by a flange similar to
lower flange (24). This enables plywood or other panel to be laid
flat on the composite joist members. The rim member is also
modified to remove the embedment loops and present a flat upper
surface.
[0104] FIG. 12 is a perspective of a further embodiment of floor
system illustrating another embodiment of the invention, for
supporting a panel floor typically of plywood, with the rim member
modified from FIG. 11. In this case the edge flange (136) is shown
turned down.;
[0105] FIG. 13 is a perspective of a further embodiment of floor
system using composite joist members illustrating another
embodiment of the invention, in which the rim members are supported
on the edge of a wall frame formed of metal studs. The panels are
of plywood or the like and thus the composite joist members do not
have embedment edges. This is shown supported on the upper plate of
a wall frame. The wall frame is also formed of metal studs, which
are distinct from the composite joist members.
[0106] FIG. 14 is a perspective of a further embodiment of floor
system using single joist members. In this case the joist members
have the same features as the joist members (20) of FIG. 1, but are
used singly, and not fastened back to back.
[0107] FIG. 15 is a perspective of a further embodiment of floor
system using composite joist members illustrating another
embodiment of rim member in which the flange is of reduced width
compared to FIG. 1. In this case it is possible to reduce the width
of the flange of the rim member. This is possible because the rim
member is already supported on the plate channel of the wall
frame.
[0108] The rim member is otherwise similar to the rim member of
FIG. 1.
[0109] The foregoing is a description of a preferred embodiment of
the invention which is given here by way of example only. The
invention is not to be taken as limited to any of the specific
features as described, but comprehends all such variations thereof
as come within the scope of the appended claims.
* * * * *