U.S. patent application number 09/543738 was filed with the patent office on 2002-01-24 for variable length truss and method for producing the same.
Invention is credited to Sanford, Emmett Barry, Stanford, Emmett Cecil JR..
Application Number | 20020007611 09/543738 |
Document ID | / |
Family ID | 26730334 |
Filed Date | 2002-01-24 |
United States Patent
Application |
20020007611 |
Kind Code |
A1 |
Sanford, Emmett Barry ; et
al. |
January 24, 2002 |
Variable length truss and method for producing the same
Abstract
An open web beam composed of wooden top chord and an open web
central structure terminated on at least one end by wooden members
in the form of a closed web wherein the closed web is reinforced by
insertion of a portion of the closed web into a strut and the two
chords which have been slotted or grooved for this purpose. The
closed be being oriented strand board using structural adhesive
without interfering mechanical fasteners in the web.
Inventors: |
Sanford, Emmett Barry;
(Columbus, MS) ; Stanford, Emmett Cecil JR.;
(Vernon, AL) |
Correspondence
Address: |
SMITH, GAMBRELL & RUSSELL, LLP
1850 M STREET, N.W., SUITE 800
WASHINGTON
DC
20036
US
|
Family ID: |
26730334 |
Appl. No.: |
09/543738 |
Filed: |
April 5, 2000 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
09543738 |
Apr 5, 2000 |
|
|
|
09092040 |
Jun 5, 1998 |
|
|
|
09092040 |
Jun 5, 1998 |
|
|
|
08914228 |
Aug 19, 1997 |
|
|
|
5761872 |
|
|
|
|
08914228 |
Aug 19, 1997 |
|
|
|
08472769 |
Jun 7, 1995 |
|
|
|
08472769 |
Jun 7, 1995 |
|
|
|
08052209 |
Apr 21, 1993 |
|
|
|
Current U.S.
Class: |
52/694 |
Current CPC
Class: |
Y10T 156/108 20150115;
Y10T 156/1066 20150115; Y10T 156/1074 20150115; Y10T 156/1064
20150115; E04C 3/16 20130101 |
Class at
Publication: |
52/694 ;
52/729.4; 52/730.7; 52/731.1 |
International
Class: |
E04C 003/16 |
Claims
What is claimed is:
1. A variable length end segment for a truss having an open web
section comprising: a closed web member having a top side, a bottom
side, an inboard side and an outboard side; an upper member and a
lower member fixed to said top side and said bottom side of said
web member, respectively, and said inboard side of said web member
abutting a strut of said truss, said strut being located outboard
of the open web section, said outboard side of said web member
forming an outer surface of said truss; and means including said
upper member, said lower member and said web member for forming a
trimmable weight bearing I-beam section.
2. A variable length truss for use in a structure an a ceiling, a
roof or a floor joist comprising: an upper chord, a lower chord and
a closed web member, said closed web member being located at one
end of said truss between said upper chord and said lower chord; a
strut between said upper chord and said lower chord, said closed
web member having an inboard side abutting said strut and an
outboard side forming an outer surface of said truss; means
including said upper chord, said lower chord and said closed web
member for forming a trimmable weight bearing I-beam section at
said one end of said truss; and an open web section between said
upper chord and said lower chord and inboard of said closed web
member.
3. The truss of claim 2 further comprising: a second closed web
member located at a second end of said truss between said upper
chord and said lower chord; a second strut between said upper chord
and said lower chord, said second closed web member having an
inboard side abutting said second strut and an outboard side
forming a second outer surface of said truss; and means including
said upper chord, said lower chord and said second closed web
member for forming a second trimmable weight bearing I-beam section
at said second end of said truss.
4. A variable length truss used in a structure an a ceiling, a roof
or a floor joist comprising: a closed web member having a top side,
a bottom side, an inboard side and an outboard side: an upper chord
and a lower chord fixed to said top side and said bottom side of
said closed web member, respectively, and a strut extending between
said upper chord and said lower chord and abutting said inboard
side of said closed web member, said outboard side of said closed
web member forming an outer surface of said truss; and means
including said upper chord, said lower chord and said closed web
member for forming a trimmable weight bearing I-beam section, said
I-beam section being trimmable up to a distance as defined by the
length of said closed web member.
5. The truss of claim 4 further comprising: a second closed web
member having a top side, a bottom side, an inboard side and an
outboard side; said upper chord and said lower chord fixed to said
top side end said bottom side of said second closed web member,
respectively, and a second strut extending between said upper chord
and said lower chord and abutting said inboard side of said second
closed web nebr, said outboard side of said second closed web
member forming an outer surface of said truss and means including
said upper chord, said lower chord and said second closed web
member for forming a second trimmable weight bearing I-beam
section, said second I-beam section being trimmable up to a
distance as defined by the length of said second closed web
member.
6. A family of variable length trusses for installation in a
structure as ceiling, roof or floor joists, each one of the trusses
comprising: a closed web member located at one end of said truss;
means including said closed web member for forming a trimmable
weight bearing I-beam section at said one end of said truss; the
total amount trimmable from said weight bearing I-beam section
defining a predetermined distance; and an open web section located
inboard of said closed web member; and said family of trusses being
in different spans beginning with a shortest truss having a first
span and increasing in length by increments of said predetermined
distance to a longest truss having a longest span, and said family
of trusses providing a source of a truss of any span from said
first span trimmed by said predetermined distance to said longest
span of said longest truss by appropriate trimming of said weight
bearing I-beam section on a respective one of said family of
trusses when the length needed is not said first span or other
spans corresponding to increasing increments of said predetermined
distance.
7. The trusses of claim 6 wherein said family of trusses is made to
an inventory rather than to specifications for a structure.
8. A family of variable length trusses for installation in a
structure as ceiling roof or floor joists, each one of the trusses
comprising: (a) a first closed web member located at a first end of
said truss; (b) means including said first closed web member for
forming a first trimmable weight bearing I-beam section at said
first end of said truss; (c) a second closed web member located at
a second end of said truss; (d) means including said second closed
web member for forming a second trimmable weight bearing I-beam
section at said second and of said truss; (e) the total amount
trimmable from said first and said second weight bearing I-beam
sections defining a predetermined distances and (f) an open web
section between said first and said second weight bearing I-beam
sections; and said family of trusses being in different spans
beginning with a shortest truss having a first span and increasing
in length by increments of said predetermined distance to a longest
truss having a longest span, and said family of trusses providing a
source of a truss of any span from said first span trimmed by said
predetermined distance to said longest span of said longest truss
by appropriate trimming of said first and/or second weight bearing
I-beam sections on a respective one of said family of trusses when
the length needed is not said first span or other spans
corresponding to increasing increments of said predetermined
distance.
9. The trusses of claim a wherein said family of trusses is made to
an Inventory rather than to specifications for a structure.
10. A family of variable length trusses for installation in a
structure as coiling, roof or floor joists, each one of the trusses
comprising: an upper chord, a lower chord and a closed web member
located a one end of said truss between said upper chord and said
lower chord, said closed web member having an outboard side forming
an outer surface of said truss; means including said upper chord,
said lower chord and said closed web member for forming a trimmable
weight bearing I-beam section at said one end of said truss; the
total amount trimmable from said weight bearing I-beam section
defining a predetermined distance; and an open web section between
said upper chord and said lower chord and inboard of said closed
web member; and said family of trusses being in different spans
beginning with a shortest truss having a first span and increasing
in length by increments of said predetermined distance to a longest
truss having a longest span, and said family of trusses providing a
source of a truss of any span from said first span trimmed by said
predetermined distance to said longest span of said longest truss
by appropriate trimming of said weight bearing I-beam section on a
respective one of said family of trusses when the length needed in
not said first span or other opens corresponding to increasing
increments of said predetermined distance.
11. The trusses of claim 10 wherein said family of trusses is made
to an inventory rather than to specifications for a structure.
12. A family of variable length trusses for installation in a
structure as coiling, roof or floor joists, each one of the trusses
comprising; (a) an upper chord, a lower chord and a first closed
web member located at a first end of said truss between said upper
chord and said lower chord, said first closed web member having an
outboard side forming an first outer surface of said truss; (b)
means including said upper chord, said lower chord and said first
closed web member for forming a first trimmable weight bearing
I-beam section at said first end of said truss; (c) a second closed
web member located at a second end of said truss between said upper
chord and said lower chord, said second closed web member having an
outboard side forming a second outer surface of said truss; (d)
means including said upper chord, said lower chord and said second
closed web member for forming a second trimmable weight bearing
I-beam section at said second end of said truss; (e) the total
amount trimmable from said first and said second weight bearing
I-beam sections defining a predetermined distance; and (f) an open
web section between said upper chord and said lower chord and said
first and said second weight bearing I-beam sections; and said
family of trusses being in different spans beginning with a
shortest truss having a first span and increasing in length by
increments of said predetermined distance to a longest truss having
a longest span, and said family of trusses providing a source of a
truss of any span from said first span trimmed by said
predetermined distance to said longest span of said longest truss
by appropriate trimming of said first and/or second weight bearing
I-beam sections on a respective one of said family of trusses when
the length needed is not said first span or other spans
corresponding to increasing increments of said predetermined
distance.
13. The trusses of claim 12 wherein said family of trusses is made
to an inventory rather than to specifications for a structure.
Description
BACKGROUND OF THE INVENTION
[0001] This invention relates broadly to the art of construction
trusses and joists.
[0002] More particularly the invention relates to open web truss
designs for application to ceiling, roof and floor joists.
[0003] More particularly the invention relates to a process and
product for use as trimmable trusses or joist which combine the
benefits of open web truss construction with closed web
construction providing variable length while conserving the
integrity of the factory test requirements and component strength
with variable spans.
[0004] Truss designs in the prior art envision three broad design
types.
[0005] Two by ten or two by twelve joists made of solid wood are
very common. The major problems associated with these are that they
require old growth timber to provide wide enough lumber. In
addition, when oriented edgewise, they provide. an inferior nailing
surface compared with that provided by two by fours oriented
flatwise. This is particularly important when adding subfloors and
ceilings to the joists since only an approximate location of the
supporting member can be found. In addition, span lengths are
greatly diminished by the load bearing properties of these
timbers.
[0006] To address the cost, assembly and load bearing problems,
manufactured trusses utilizing two by four chords with an interior
webbing have been used. Two basic types encompass the two remaining
truss design types.
[0007] Open web trusses of several designs are known in the art. An
example of an open web truss is White, 1,565,879. White discloses a
truss having a web of the depth of the truss which is shaped at
either end to fit within a recess in the upper and lower chords
which are provided with channels for receiving the shaped ends. The
shaped ends are part of a web which has been thickened and provided
with a flanged seat for placement of the truss during construction.
The web and the chords have had their structural integrity and
stress bearing features affected by the process. The present
invention maintains structural parameters.
[0008] Further, If the seat is removed, as by trimming, the
effectiveness and purpose of this structure is negated.
[0009] White also provides for a complex and built up leading and
trailing edge for purposes of maintaining strength and hanging the
truss. The webs making up the I-beam ends are mounted by way of
channels in the chords which hold the diagonal struts by
compressing the sides of these channels. Fillets are pressed into
the wood in order to anchor this engagement.
[0010] These trusses are particularly described to define a
non-trimmable truss. The net effect of trimming a truss of this
form would be to affect the structural integrity built into the
truss by virtue of the fillets and cause potential splitting at the
channels holding the struts.
[0011] A similar design is disclosed in the pressed in dovetail
type joint disclosed in Keller, et al 3,991,535. Keller shows the
use of grooved members between parallel tongues (corresponding to
the chords of White) for receiving an I beam of a truss
(corresponding to the webs of White).
[0012] Keller discloses the difficulty of using dovetail joints and
addresses a method of improving this design. Keller discloses the
use of glue in order to strengthen the glued dovetail of the
joints.
[0013] The invention is directed to a joint which is self clamping
in order to avoid or decrease the need for structural
improvements.
[0014] These are shown as incremental portions of a partially open
web truss in Keller. Keller also fails to utilize two by four open
webbing, also generally referred to as cross webbing which adds
strength and reduces costs of construction as well as enhancing the
crush strength of the interior web and providing greater
opportunity to run conduit and pipes through the component.
[0015] King, 2,668,606 shows an I-beam utilized in the end piece of
prefabricated steel beams.
[0016] Seegmiller, 4,699,547 shows a variable length truss and the
problems of maintaining structural integrity of the members is
indicated.
[0017] In all of the patients utilizing wooden members, the shape
and structure and therefore the integrity of the web members has
been altered since the structure can be kept within limits by
maintaining the length of the truss.
[0018] One of the problems recognized by the present example is
that I-beam construction of this type results in an inability to
make on site corrections to the length of trusses. This problem can
result in the need to re-manufacture the entire truss.
[0019] To address this problem in the past, construction techniques
used have included a closed web of the type shown in Keller
extending the entire length of the structure. As with Keller, this
creates a number of problems. First, at least a portion of the
interior webbing is closed and cannot be used for running lines or
conduit without bracing, known generally in the art as web
stiffeners, being added and calculations being necessary for
determining the stability and crush strength of the altered
bracing. In order to have a safety. factor built in solid web
construction as designed for cutting into variable lengths with a
varying location for the load has required that the entire beam be
made of a solid web.
[0020] Note that Keller could not be cut without raising a number
of questions as to crush strength and load bearing location. At a
very minimum web stiffeners would need to be used, again. requiring
engineering on the site.
[0021] The closed truss is the most common variable length truss.
Closed truss design suffers from several construction problems.
First, the design requires a great deal more material, having a
closed volume. Second the design has difficulty with respect to
working within the area defined by the interior of the truss since
it is solid and must be cut for additional work. This provides for
two problems. First, the strength of the truss may be affected by
the work. Second, a great deal of time and equipment may be
necessary in order to manufacture a space in which to work. Other
related problems may exist as a result of these general problems
including the need to use "web stiffeners" and engineer where holes
may be made and where web stiffeners are to be placed.
[0022] In addition to other reasons, the weight of these types of
trusses make them hard to ship and hard to work with.
[0023] The major problems with the solid web, other than the
inability to use it easily in the field without engineering to pass
conduit, is the cost. Solid webbing of the type needed to
distribute stress is an expensive value added wood manufactured
product comprises of glue and chips compressed together.
[0024] The prior art has failed to date to provide an open web
truss which has a variable length and this failing has required
that all cross web construction be made to order requiring huge
risks of error, high turn around times and inflexibility for the
end user. The prior art also fails to show a trimmable truss which
does not require on site modification to maintain crush
strength.
[0025] The prior art also fails to show a method for constructing
trusses with web strengtheners in place at a low cost.
[0026] It is therefore the primary object of the invention to
provide a new truss or joist incorporating the benefits of open
webbing with variable length structural components required in the
industry.
[0027] It is a further object to provide a structural components
which can replace expensive and environmentally unsound two by ten
or two by twelve floor and ceiling joists.
[0028] It is therefore an object of this invention to produce a
truss which can be of variable length without affecting the
structural integrity of the truss I-beam section and maintaining a
particular crush strength. It is a further object to provide a
varying location for the load bearing surface.
[0029] It is a further object of the invention to provide a truss
which has a variable load point on either end of the truss.
[0030] It is further object of the invention to produce trusses of
variable lengths having trimmable ends without requiring on site
engineering.
[0031] It is a further object of this invention to teach a method
of constructing trusses of variable length.
[0032] It is a further object of the invention to teach a method of
simplifying cross web truss construction.
[0033] It is a further object of this invention to disclose a
system for construction utilizing variable length trusses.
[0034] These and other objects and advantages of the invention will
become better understood hereinafter from a consideration of the
Specification , with reference to the accompanying drawings forming
a part thereof and .in which like numerals correspond to parts
throughout the several views of the invention. 3. General
Discussion of the Invention
[0035] 1. Technology
[0036] All products envisioned under this patent would be designed
in accordance with the National Design Specifications (1991) and
the recommendations of the Truss Plate Institute (PCT-80). Thus,
compliance to local building codes would be assured.
[0037] Modern, high strength, structural adhesives and special
equipment make possible the fabrication of end sections without the
use of any mechanical fasteners so that lengths may be modified in
the field.
[0038] 3/4' OSB (oriented strand board) is used to maintain
strength away from the we stiffeners used.
[0039] For architects and volume purchasers, technical assistance
from industry experts end professional engineers would be available
where necessary for the method of use.
[0040] 2. The Advantages of the system would include:
[0041] A. In-field customization for a closer hand fit.
[0042] B. Higher strength allows longer spans with greater
on-center spacing-resulting in a net savings in total board-feet of
wood fiber (about 12% less than typical 2.times.12 construction)
and less deflection.
[0043] C. Open web construction allows for easy passage of duct
work, conduit and pipe throughout the length of the TrimJoist-no
more hole cutting or notching with consequent problems.
[0044] D. The 4.times.2 chord orientation provides a greater
nailing surface for decking, thereby reducing squeaks and giving a
more rigid floor system. Minimum chord grade is #1 SP in the
preferred embodiment.
[0045] E. Environmentally Friendly-all wood fiber can be supplied
from plantation-grown trees. Unlike 2.times.12s, no "old growth"
forest lumber is required when framing with TrimJoist.
[0046] Examples of the structural aspect of inventions built within
the parameters of the disclosure set forth herein follow in the
following tables:
1 SPAN/DEFLECTION TABLE Stock Length 4' 6' 8' 10' 12' 14' 16' 18'
Span Range Minimum 1'-9" 3'-9" 5'-9" 7'-9" 9'-9" 11'-9" 13'-9"
15'-9" Maximum 3'-9" 5'-9" 7'-9" 9'-9" 11'-9" 13'-9" 15'-9" 10'-9"
Max Live Load .01" .01" .03" .06" .11" .20" .34" .52" Deflection
Max Total .02" .02" .04" .08" .17" .30" .50" .77" Load Deflection
Maximum L/D 4.3 6.4 8.5 10.7 12.8 14.9 17.1 19.2
[0047]
2 UNIFORMLY DISTRIBUTED PSF LOADING (0% Stress Increase) Top Chord
Live: 40.0 50.0 60.0 70.0 80.0 Top Chord Dead: 10.0 12.5 15.0 17.5
20.0 Bottom Chord Live: 0.0 0.0 0.0 0.0 0.0 Bottom Chord Dead: 10.0
12.5 15.0 17.5 20.0 TOTAL LOAD: 60.0 75.0 90.0 105.0 120.0 SPACING:
24.0" 19.2" 16.0" 13.7" 12.0"
[0048] Strongback Note (Web strengtheners): By way of example, the
invention envisions in certain cases web fasteners when utilizing
two by four construction. For example, a 2.times.4 #2SP (or equal)
strongback is required when span exceeds 9'-9". Install
perpendicular to one vertical member at either side of center
chase. Attach using 2-10 d nails, staggered through strongback into
vertical member. Strongback is to run continuously and be properly
nailed to each member. If splicing is necessary, use 4' long scab
centered over each splice and attach using 10d nails at 4' c/c
spacing.
[0049] Anchorage Note: Web strengtheners would be attached with
device(s) deemed suitable for use in conjunction with provided
support (see architect or building designer).
BRIEF DESCRIPTION OF THE DRAWINGS
[0050] For a further understanding of the nature and objects of the
present invention, reference should be made to the following
detailed description taken in conjunction with the accompanying
drawings in which like parts are given like reference numerals and
wherein:
[0051] 1. FIG. 1 is a perspective view of the preferred
embodiment.
[0052] 2. FIG. 2 is a cross sectional view of FIG. 1 through the
A-A axis.
[0053] 3. FIG. 3 is a break down of a detailed section of the
trimmable I-beam used in FIG. 1.
[0054] 4. FIG. 4 shows the I-beam of FIG. 3 as assembled.
[0055] 5. FIG. 5 shows the process described herein for making
Truss sections using the technology disclosed in the
specification.
[0056] FIG. 5a is a typical square cut detail. FIG. 5b is a tpyical
rafter cut detail,
[0057] 6. FIG. 6 shows the use of succeedingly two foot increases
in beam size for purposes of use of the product in
construction.
DETAILED DISCUSSION OF THE PREFERRED EMBODIMENT(S)
[0058] As can best be seen by reference to FIG. 1, the structural
component system 1 is constructed of a series of individual truss
members as shown as 2 in FIG. 2 and the ends of the structural
component are constructed of wooden flanges separated by a vertical
wooden solid web material.
[0059] As can best be seen by FIG. 2, each of the cross member 3 is
constructed generally using cross beams 3 and chords 5. An end unit
6 comprised of a strut 7 and a closed web 8 complete the interior
portions. The chords are bound to the struts 7 and the cross
members 3 utilizing metal fasteners 4. These fastener 4 are known
in the art and appear as a metal sheet out of which sharp points or
nails have been punched. Typically, these fasteners 4 need to be in
place on both sides of the cross beams 3, struts 7 and chords 11
and 12. A smaller fastener 4a is used in order to secure the top or
bottom of vertical beams 9 defining duct opening 10 and the top of
struts 7.
[0060] The strut may be slanted as required by roof type truss
members.
[0061] As can best be seen by reference to FIG. 3 and 4 a key
element of the invention is the end unit 6. End unit 6 is comprised
on the weight bearing end of the top chord 11 and bottom chord 12.
The ends of chords 11 and 12 have been fitted to have a top groove
13 and a bottom groove 14. These grooves 13 and 14 correspond to
the top plug 15 and bottom plug 16 defined by the top. and bottom
rounded ends of the solid web 8. The grooves are typically 1/2' in
a 2.times.4 chord to maintain thickness of the 2.times.4 during
curing and when weight is supplied during use.
[0062] The grooves 13 and 14 and corresponding plugs 15 and 16 are
rounded in order to provide a smooth stress profile when pressed
together tightly, as by the construction technique described below
for making the truss or by loads pressing on the truss in a
construction setting. Square or non-rounded openings as are present
in the prior art at these locations result in stress singularities
which can cause cracking. By providing semi-circular grooves, the
stresses present are evenly distributed without affecting the
strength of the lumber. Typically, in a two by four, these grooves
would be approximately 1/3 of the depth of the two by four. This
shaping also allows for a better method of manufacture by allowing
easier insertion with the plugs 15216.
[0063] Closed web 8 is longer than strut 7 by the combined depth of
grooves 13 and 14. Strut 7 has a height defined by the spacing
desired between the top chord 11 and bottom chord 12.
[0064] Glue line 18 serves to fix the side 21 of closed web 8 into
a slot 22 in the strut 7. In addition, in order to maintain the
location and pressure on the glue line 18 during curing, metal
staples or pins 23 are used to further secure the strut 7 to the
side 21 of closed web 8.
[0065] Top glue line 19 and bottom glue line 20 are used to secure
top plug 15 and bottom plug 16 into top groove 13 and bottom groove
14 respectively. The metal pins 24 cannot extend into the closed
web 8 a greater distance than that encompassed by the sides of the
slot 22. Slot 22 and the side 21 of web 8 are squared to facilitate
the introduction of the pins 23. The slot 22 and side 21 may be
squared since they do not bear significant and controlling
stresses.
[0066] The length of the grooves 13 and 14 and corresponding length
of the top 15 and bottom 16 of closed web 8 may be different
without departing from the inventive concept embodied herein
overall depth from top to bottom amy also vary-length of side 21 on
FIG. 3 can vary as well.
[0067] The combination of the chords and strut and closed web as
described above may form a trimmable I-beam without sacrificing
strength or deflection tolerances utilizing normal two by four
construction for the chords and strut and having the closed web
comprised of oriented strand board having a top grooved face
corresponding in shape to the top groove and a bottom grooved face
corresponding to the shape of the bottom groove so as to form a fit
is joined by structural adhesive by joining the top groove and
bottom groove to the top and bottom grooved faces respectively.
[0068] The real benefit of having the trimmable end in combination
with the open web construction can be seen by reference to FIG. 1.
As seen by FIG. 1, the running of conduit 24 is simplified by
having the open web design. Because the end of the structural
components 2 is capable of modification, the structural components
2 may be mass produced instead of job ordered. Close tolerances can
be maintained during factory assembly. Unlike a solid web as is
known in the art, no special cuts need to be made in the interior,
the components are strengthened by struts resulting in an open web
and less material needs to be used.
[0069] This results in a substantial savings in turn around time,
cost savings, material quantity and weight savings, and labor
savings since the engineering of specific trusses is taken care of
prior to delivery. Other aspects of engineering required by cutting
openings for conduit are also eliminated.
[0070] The width and height of the solid web 8 for the invention is
defined by the requirements of chord load in the center of the open
web and the fact that a minimum amount of length solid webbing 8 is
desired to keep the web stiffener 7 effective and to control costs.
As described below 2' of solid webbing 8 allows for mass production
usage.
[0071] In addition, by having these variable length trusses in
several sizes, they may be stocked like two by twelve truss members
allowing for easier availability than with prior art products.
[0072] Finally, as described in more detail below, the construction
of this particular type of truss provides for an improved method of
construction of open web structural components.
[0073] The method for using the members described herein envisions
a line assembly of the components.
[0074] First, the size of the unit must be determined and
engineered using known specifications for open web cross web
construction reduced for the length of trimmable closed webbing on
at least one side of the truss. In the preferred embodiment, the
closed webbing appears on either side to allow easy use.
[0075] In order to allow that only a single strut 7 is necessary
per side, thereby avoiding the need for on site web stiffening,
typically only one foot on either side of the truss 2 utilizes
closed webbing 8. Closed or solid web 8 allows for a variable
bearing point as apposed t a fixed bearing part as in other open
web construction. It is obvious given the disclosure that web
stiffening may be provided at other locations to allow for longer
runs of closed webbing 8 as by having either side of the strut 7
grooved to receive the front of one section of closed webbing and
the back of another section of closed webbing.
[0076] The sections determined necessary for typical use as shown
in FIG. 6 would include sections of 20 feet, 18 feet, 16 feet, 14
feet, 12 feet, 10 feet, 8 feet, 6 feet and 4 feet. Every 4 foot
section typically would have two cross members 3. Every 6 foot
section would have two cross beams 3 and two vertical beams 9 to
define a square duct opening 10. For all the longer trusses, for
every two feet added, an additional two cross 3 would need to be
added. The beauty of this system is that, since all of the truss
sections are trimmable by two feet, every imaginable size up to the
maximum span of 24 feet (the maximum being arbitrarily determined),
is included.
[0077] Because this provides for a series of sections, which may be
assembled by size needed, it is possible to extend the size without
changing the basic specifications. Because all sizes are covered, a
warehouse may stock the product as an alternative to more expensive
solid web units or two by twelve or ten units.
[0078] A method of constructing floor and ceiling joists utilizing
open web construction without having exact span specifications is
disclosed by:
[0079] 1. preparation of a series of trimmable open web member of
variable length having closed web ends for trimming;
[0080] 2. Determining by mental operation the number of joists of
each size are needed utilizing the desired spans;
[0081] 3. Trimming the joists of the appropriate size on the site
to fit within specific parameters of the site as constructed.
[0082] The method envisioned for producing a superior and
simplified cross web truss utilized in this specification can be
set out as several steps as illustrated in FIG. 5.
[0083] The first step in the production of units of variable sizes
having an open web design with a trimmable end comprises the step
of:
[0084] (a) determining the separation distance of the cords;
[0085] (b) next would be cutting the two struts in the desired
determined length to maintain the desired space between the chord
members;
[0086] (c) cutting square cuts within the struts to receive the
solid web;
[0087] (d) cutting a solid web so as to have a side to fit within
the square cuts and extend to form a plug on either side of the
strut;
[0088] (e) cutting or molding the solid web so as to form plugs
having curved ends on either side of the struts;
[0089] (f) placing glue within the square cut;
[0090] (g) placing the web and struts within a jig to align the
square cut on the side of the web with the square cut on the
strut;
[0091] (h) compressing the side of the web within the square
cut;
[0092] (i) fixing the web to the strut with two staples to maintain
the position and tension on the glue during the setting so that
there is a mounting of the length of solid webbing to the strut and
perpendicular to strut at a set location on the strut and running
perpendicular to the intersection of the strut with the chord
member (and extending beyond the point of intersection of the strut
with the chord member so as to allow the chord member to be cut to
receive the solid webbing;
[0093] (j) cutting grooves within the top chord to receive the
portion of the solid webbing extending beyond the point of
intersection of the strut and cutting groove within the bottom
chord to receive the portion of the solid webbing extending beyond
the point of intersection of the strut corresponding and opposite
to the location of the cut in the top chord so that when the top
plug and bottom plug are within the corresponding the grooves, the
top chord and the bottom chord are aligned.
[0094] (k) placing the bottom chord on a rack;
[0095] (l) securing the bottom plug to the bottom groove on at
least one end of the bottom chord utilizing a glue line in the top
groove;
[0096] (m) securing the top chord to the top groove so as to align
the chords utilizing a glue line in the bottom groove; securing the
top chord and top plug and bottom chord and bottom plug on either
end of the chords. The use of the separator described in FIG. 3 and
4 and steps a-i is particularly important as the separation defined
by the separator is key to the truss strength as to central chord
stress as opposed to bearing stress on the closed web on either
end.
[0097] (n) putting a top rack on top of the bottom rack;
[0098] (o) compressing the top rack onto the bottom rack as by
compressing one rack to the other;
[0099] (p) inserting sections of cross webbing within the space
formed by the at least one strut between the chords.
[0100] Because of the many and varying and different embodiments
which may be made within the scope of the inventive concept herein
taught, and because many modifications may be made in the
embodiments herein detailed in accordance with the descriptive
requirements of the law, it is to be understood that the details
herein are to be interpreted as illustrative and not in a limiting
sense.
* * * * *