Note: Descriptions are shown in the official language in which they were submitted.
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CROSS REFERENCE TO RELATED APPLICATIONS
United States Patent No. 4,485,606 entitled TRUSS STRUCTURES
CONSTRUCTED WITH METAL WEB ME,VIBERS which names
Robert Gottlieb as the inventor and which is assigned to the assignee of the present
invention, discloses trusses and metal brackets which may be used for constructing
trusses in accordance with the present invention.
BACKGROUND OF THE INVENTION
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Field of the Invention
The present invention relates to wooden trusses used for supporting structural
loads and to hardware used in constructing wooden trusses which enhances the ease of
installation and increases the resultant structural rigidity of the installed trusses for
bearing structural loads.
Description of the Prior Art
In constructing various types of wooden truss assemblies, including both roof
trusses and floor joists, it has been common to use large wooden structural members
such as 2" x 10"s. Such large wooden members, however, are becoming increasinglydifficult to obtain and have increased in cost substantially. Consequently various
alternatives have been sought for enabling the construction of trusses which are able
to bear the structural loads of full dimension lumber but which are constructed from
smaller pieces of dimension lumber such as 2" x 4" members which are spaced apart by
metal connectors. Substitutes for full dimension lumber roof trusses and floor joists
must satisfy two primary criteria. First, the trusses must be able to withstand large
compressive loads so that they may be used for bearing substantial structural loads.
Secondly, it is desirable that the trusses be prefabricated at a manufacturing plant at
a low labor cost and shipped to a building site without a high degree of risk of incurring
damage to the trusses.
Various types of hardware have been developed for making prefabricated trusses.
United States Patents 3,025,577 to Gyrate, 3,298,151 to Gyrate and 4,078,352 to Knowles
3 0 and the aforementioned I, 485,606 are representative of metal connector which
have been used for manufacturing trusses from dimension lumber such as 2" x us
The aforementioned United States Patent No. 4,485,606 entitled
TRUSS STRUCTURES CONSTRUCTED WITH METAL WEB MEMBERS
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discloses a metal web member which has a reinforced leg having a projection
t which runs substantially the entire length of the leg and which projects in the direction
of the sharp projections of connecting plates disposed at the ends of the leg. The
height of the projection varies from a maximum in proximity to the connecting plates to
a minimum in proximity to the midpoint between the connecting plates. f\ pair offlanges are joined to the outside edges of the leg along the length of the leg which
flanges project in the direction of the sharp projections of the connecting plates. The
height of the projection of the flanges varies from a minimum in proximity to the
connecting plates to a maximum in proximity to the midpoint between the connecting
plates. A pair of projections at each end of the legs may be used in place of the
single projection which extends the length of the leg.
Attachment members have been marketed for connecting together the spaced
apart wooden members which are used for constructing trusses. These attachment
members have first and second connecting plates disposed at opposite ends of an
intermediate section which extends transversely between the ends of of the spaced
apart first and second wooden member of the truss. The intermediate section Go the
aforementioned attachment members contains a plurality of ridges which project outward
away from the direction that the sharp projections in the connecting plates project
when engaging the spaced apart first and second wooden members of the truss.
Trusses have been installed at the building site in a number of ways. If the
trusses are being used to construct a floor, they may be laid on top of the foundation
walls and nailed into a beam which extends perpendicular to the longitudinal axis of
the trusses. The trusses have been nailed in place by tunneling through various surfaces
of the wood at the end of the truss.
It has been found that trusses of long length have the property of flexing to anundesirable extent if the center between the ends of the truss is not r raced with a
transverse beam when heavy structural loads are placed near the center. Thus, while it
is the case that trusses manufactured at factory sites have eliminated the need for
using expensive full dimension lumber, it is nevertheless the case that to some extent
they have the property of undesirable fluctuation when they are used for long spends in
supporting heavy structural loads.
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Solver OF THE INVENTION
It is an object of the invention to provide an improved truss assembly which hasincreased rigidity in proximity to unsupported sections which are sub jet to large amounts
of fluctuation.
It is a further object of the invention in providing increased rigidity in proximity
to the unsupported section of the truss assembly to provide a mechanism for attaching
a beam running transverse to the longitudinal axis of the trusses for supporting the
unsupported sections of the truss assembly.
It is a further object of the invention to provide an attachment memoir which
may be secured transverse to the longitudinal axis of the spaced apart upper and lower
wooden members to provide increased rigidity and resistance to twisting and compression.
The invention includes a bracing clip for use in supporting a beam running
transverse to a plurality of spaced apart wooden members such as those found in trusses,
and an attachment member for connecting together the spaced apart wooden membersof the truss and truss assembly using the aforementioned bracing clips and attachment
members.
The bracing clip is a mechanism for rigidly attaching a supporting beam running
transverse to a wooden member such as the wooden members found in trusses. When
the bracing clip is used in conjunction with a plurality of spaced apart trusses which
2 0 are supporting a heavy structural load, it is attached to a beam running transverse to
the longitudinal axis of the trusses disposed between the spaced apart wooden members
of each truss to provide increased structural support to minimize undesirable fluctuation
consequent from the bearing of the heavy structural load.
An attachment member in accordance with the invention provides a mechanism
for connecting together the ends of the wooden members within individual trusses to
provide increased rigidity and resistance to compression and torsional loading which
could cause the upper and lower wooden members within the truss to twist with respect
to each other. The attachment member may also be used to couple together other types
of spaced apart wooden members other than those found in trusses.
3 o A bracing clip for use in supporting a beam running transverse to a wooden
member in accordance with the invention includes a connector plate disposed within a
first plane having a plurality of sharp projections extending generally perpendicular
from the plane of the plate for use in fixedly attaching the connector plate to the top
wooden member of the truss; a first surface attached to and extending from the connector
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plate within the first plane; a second surface disposed within a second plane which is
attached to the first surface and forming approximately a 90 angle with the first
surface, the second surface being parallel to the longitudinal axis of the beam when
the second surface is in contact with the beam; a third surface disposed within a third
plane which is joined to the second surface and forming approximately a 90 angle with
the second plane, the third surface being substantially perpendicular to the first plane;
and the third surface being adapted for attachment to the beam underneath and across
its thickness.
The bracing clip may also include a forth surface disposed in a fourth plane which
is joined to the third surface at approximately a 90 angle; the fourth plane being
substantially parallel to the second plane and projecting in the same direction as the
second surface toward the connector plate.
The second and third surfaces may have a plurality of apertures adapted for
receiving nails to secure the second and third surfaces respectively into engagement to
the width and bottom of the beam.
In its preferred form, a bracing clip in accordance with the invention is tapered
in width from a maximum width to a minimum width, the point of attachment of thefirst surface to the connector plate being the maximum width of the first surface and
the end of the first surface farthest from the point of attachment being the minimum
width; and the second surface is tapered in width from a maximum width to a minimum
width, the maximum width of the second surface being located in proximity to theminimum width of the first surface and the minimum width of the second surface being
located in proximity to the maximum width of the first surface.
An attachment member in accordance with the invention which is adapted for
connecting two pieces of spaced apart wood together includes first and second connecting
plates disposed at opposite ends of an intermediate section, the connecting plates each
having a plurality of sharp projections extending generally perpendicular from the plane
of the connecting plates, the connecting plates being disposed in the same general
plane; the intermediate section having at least one projection projecting from the same
side as the sharp projections of the connecting plates and extending substantially the
entire length of the intermediate section between the connecting plates, the projection
being highest in proximity to the connecting plates and lowest at its center located
midway between the connecting plates and a pair of side flanges attached to and
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projecting upward from the outside edges of the intermediate section and extending in
the same direction as the projection, the height of the projection of the side flanges
varying throughout their length with the lowest projection being in proximity to the
connecting plates and the highest projection being in proximity to the mid-point of the
flanges located between the connecting plates. In the preferred form of the invention,
the maximum projection of each of the flanges is at least approximately 1/3 of the
width of the intermediate section.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 is a end view of a truss assembly in accordance with the invention
which illustrates the use of the truss hanger, bracing clip and attachment member;
Figure 2 is an isometric view of a bracing clip in accordance with the invention;
Figure I is an isometric view of a truss hanger in accordance with the invention;
Figure I is an isometric view of a modification of the truss hanger of Figure I.Figure 4 is a top view of an attachment member in accordance with the invention;Figure I is a sectional view of the top view of Figure 4 taken along section line
1- 1 and;
Figure I is a sectional view of the attachment member of Figure 4 taken along
section line 2-2.
DESCRIPTIOl~l OF Tiff PREFERRED E~!BODII~!E~TS
Figure 1 illustrates an end view of a truss 10 in accordance with the present
invention which is supported at both its ends and carries a structural load of sufficient
magnitude to cause an undesirable amount of flexing in the middle of the truss between
the points of attachment of its end. The truss 10 is manufactured from an upper
wooden member it and a lower wooden member 14 which may be made from standard
dimension lumber such as a 2" x 4" which is turned on its side so that the width of each
2" x 4" within a truss is parallel to the horizontal. The upper wooden member 12 and
the lower wooden member 14 are fixedly attached to a plurality of metal web members
16 which may be of any known construction but which preferably are those which are
described in the aforementioned Spat 4,485,606. Each of the metal web members 16has three connecting plates 18 from which have a plurality of sharp teeth-like projections
which are pressed into the wood members 12 and 14 to completely embed the projections
into the wood to securely attach the metal web member to the upper and lower wooden
members. While the design of the sharp teeth like projections is not part of the present
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invention, preferably they are manufactured in accordance with the teachings of United
States Patent 4,343,580 which is owned by the assignee of the present invention. A
pair of intermediate sections 20 connects the connecting plate 18 at the vertex with
the connecting plates at the ends. The cross-section of the intermediate section has
been specifically designed to provide increased structural rigidity against compression
and twisting consequent from the application of high structural loads to the truss and
is described in the aforementioned Spat 4,4859606. Each intermediate section 20
has one or more projections extending substantially along its entire length which project
in the direction of the sharp teeth like projections of the connecting plates 18. Each
projection is higher and wider in proximity to the connecting plates 18 than at the
midpoint located between the connecting plates. Each intermediate section has a pair
of side flanges 24 located on the outside edges which project in the same direction as
the sharp teeth like projections of the connecting plates 18. The lowest projection of
the side flanges 24 occurs in proximity to the connecting plates 18 and the highest
projection occurs in proximity to the mid-point between the connecting plates. Each
truss is supported at its ends 26 by a pair of truss end supporting beams US which run
transverse to the longitudinal axis of the trusses. While it is common practice to
support trusses with wooden beams in modern construction, it should be clearly understood
that the invention is not limited to the use of wooden truss end supporting beams 28 and
in fact may be used with any truss end supporting structure having a rectilinear cross-
section. The truss 10 is connected to the truss end supporting beams 28 by means of
a truss hanger 30 which is described in detail in Figures I and I infer. The ends
of the upper wooden member 12 and the lower wooden member 14 are braced with an
attachment member 32 which is attached adjacent to the point of attachment of the
truss hanger 30. The attachment member is described in detail infer in conjunction
with Figures 4, Rand I. One or more intermediate beams 34 provide further
structural support for the truss 10 against large structural loads. Each of the beams
extends transverse to the longitudinal axis of the individual upper and lower wooden
members 12 and 14. The intermediate beams 34 are located between the upper and
lower wooden members 12 and 14 and are fixedly attached to the upper member by
means of a bracing clip 36 which is described infer in detail in Figure 2. The function
of the bracing clip 36 is to securely attach the intermediate beams 34 to the truss 10.
It should be understood that the other side of the truss of Figure I has a corresponding
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truss hanker 30, attachment member 32, and bracing clip 36 so that in actuality each
truss has left and right hand versions of each of these elements for providing the
maximum degree of performance.
Figure 2 is an isometric view of a bracing clip in accordance with the present
S invention. The bracing clip 36 has a connecting plate 38 which has a plurality of sharp
projections 40 projecting generally perpendicularly from the plane of the connecting
plate. The projections may be made in accordance with the teachings of the
aforementioned ITS Patent 4,343,580. The projections 40 are adapted to attach the
connecting plate 38 to the upper wooden member 12 of the truss illustrated in Figure 1
but may be used alternatively to connect a beam to any wooden member from which it
is desired to support the beam transverse to the longitudinal axis of the wooden member.
A first surface 42 is disposed in a first plane and is attached to the connecting plate
38 and extends in the same plane of the connecting plate. The first surface 42 has
its maximum width 44 adjacent to the point of attachment with the connecting plate
38 and its minimum width 46 located at the other end farthest from the keynotingplate. Preferably, the first surface is a tetrahedron having an side 48 which extends
along the entire length of the first surface and which forms the point of attachment with
a second surface 50 to be described In . The second and third sides 52 and 54 ofthe tetrahedron, respectively, correspond to the maximum width 44 and the mix mum
width 46. The sides 52 and 54 are parallel to each other. The fourth side 56 extends
between the second and third sides 52 and 54. The first and fourth sides subtend an
acute angle. The second surface is disposed in a second plane and is attached to the
first surface along the first side 48 to form an approximate 90 angle therewith. The
second surface is a tetrahedron and has a shape similar to the first surface. A plurality
of apertures are contained in the second surface 50 for facilitating the attachment of
nails to the width of the beam 34 which is supported by the bracing clip 36. The plane
of the second surface extends parallel to the longitudinal axis of the beam which is
supported by the bracing clip 36 and extends in the same direction as the projections
40. A third surface 60 which is disposed in a third plane is joined to the second surface
50 and forms an approximate 90 angle with the second plane. The third surface 60
is substantially perpendicular to the first plane and is parallel to the longitudinal axis
of the intermediate beam 34. A plurality of apertures are provided in the third surface
to facilitate the connection of the bracing clip to the intermediate beam which is being
supported. A fourth surface 64, which is disposed in a fourth plane, is attached to
the third surface 60 and forms approximately a 90 angle with the third surface and
is substantially parallel to the second surface 50. The fourth surface 64 projects from
its point of attachment to the third surface 60 toward the connecting plate 38. The
fourth surface 64 is displaced from the second surface 50 by a distance which ispreferably equal to the thickness of two inch standard dimension lumber used in
construction (1.5 inches). The length of the second and third surfaces is substantially
equal to the width of the lumber the bracing clip is designed to support. While the
preferred use of the bracing clip is in conjunction with the attachment of intermediate
support beams 34 to trusses 10 as described in conjunction with Figure 1 swooper it
should be clearly understood that the bracing clip may be used for supporting other
wooden members.
The method of manufacturing the bracing clip 36 does not form part of the
invention. It should be understood that any acceptable manufacturing process forstamping out the bracing clip as previously described may be used. A single blare of
metal may be used as the starting point for fabricating of the bracing clip. Thereafter
the clip is folded to form the previously described right angles, punched to form the
apertures for providing nail holes, and further formed to produce the sharp projections 40.
Figures I and I are isometric views of truss hangers in accordance with
the present invention. The truss hanger has a bracket 70 having a first leg 72 which
is adapted to engage the side of the truss 10 and truss end supporting beam 28 across
its width. A base 74 is joined at its first end 76 to the first leg 72 of the bracket 70.
A second leg 78 is joined to the second end 80 of the base 74 at an approximate 90
angle. The second leg extends parallel to the first leg 72 and runs in the same direction
I as the first leg to form a three sided structure in conjunction with the first leg 72 and
the base 74 which functions as a bracket 70 for securely attaching the truss to the
truss end supporting beams 28. The second end 82 of the first leg 72 of bracket 70 has
a support shelf 84 joined thereto at an approximate 90 angle which functions as a
support for the lower wooden member 14 of the truss 10 of Figure 1. An attachment
3 o member 86 is joined to the edge 87 of the first leg 72 of the bracket 70 along i is
length. The attachment member 86 has a pair of connecting plates 88 located at the
ends of the attachment member. The sharp projections of the connecting plates 88 are
preferably manufactured in accordance with the aforementioned United States Patent
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4,343,580. The sharp projections 89 of the connecting plates are pressed into the sides
of the upper and lower wooden members 12 and 14 to securely attach the hanger tothe end 26 of the truss 10. The attachment member 86 has an intermediate section90 which extends between the connecting plates 88. The intermediate section 90 may
be either a flat piece of sheet metal (Figure 3(b3) which has not been reinforced to
increase its rigidity or it may have structural reinforcing elements incorporated therein
(Figure I). The preferred form of structural reinforcing elements are like thosedescribed in the aforementioned Spat 4,485,606 for reinforcing the legs extending
between the connecting plates described therein. When reinforcing elements are
incorporated, one or more projections 92 are formed in the intermediate section 90
which project in the same direction as the sharp projections 89 of the connecting plates
88. The height of the aforementioned projection 92 varies such that it reaches its
maximum height in proximity to the connecting plates 88 and reaches its minimum height
in proximity to the mid-point located between the connecting plates. The cross-section
of the projection 90 is identical to that illustrated infer in Figures I and I and
therefore will not be described in detail in conjunction with Figure 3. A single side
flange 93 is formed in the intermediate section 90 on the outside edge thereof vouch
is opposed to the first leg 72 of the bracket 70. The side flange 93 projects from the
plane of the intermediate section 90 in the same direction as the projections 89 of the
connecting plates 88. The height of the projection of the side flange 93 varies such that
it reaches its maximum height at the mid-point between the connecting plates 88 and
reaches its minimunl height in proximity to the connecting plate 88. The variation in
the height of the projection 92 and the side flange 93 is such that the width of the
intermediate section is substantially constant along its length. Preferably, the maximum
height of the flange is at least approximately 1/3 of the width of the intermediate
section. The side flange 93 has a design like that illustrated in Figures I and I
In . The vower connecting plate 88 has a support shelf 94 attached thereto at anapproximate 90 angle therewith. The support shelf 94 projects in the same direction
as the projections 89 of the lower connecting plate 88 and functions to support the
lower wooden member 14 of the truss 10. Preferably, a matched pair of left and right
hand hangers 30 are used at each end 26 of a truss 10. The only difference between
the left and right hand hangers is that the attachment member 86 is connected to the
opposite longitudinal side of the first leg 72 of the bracket 70 so that the projections
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of the upper and lower connecting plates I face in opposite directions in the left and
right hand hanger 30.
An attachment member 32 in accordance with the invention is illustrated in
Figure 4 and Figures I and I. The attachment member 32 has a pair of spaced
apart connecting plates 96 which are separated by an intermediate section 98. Each
connecting plate has a plurality of sharp teeth like projections 100 which extend
generally perpendicularly from the plane of the connecting plates 96. The projections
100 are preferably made in accordance with the teachings of United States Patent4,343,580. The intermediate section 98 has a cross sectional design which is similar to
the cross sectional design of the Jogs which space apart the connecting plates in the
aforementioned IJ.S.Pat. 4,485,~06. A projection 102 extends substantially the entire
length of the intermediate section 98. The projection 102 extends in the same direction
as the projections 100 of the connecting plates 96.
Figures I and I which are respectively sectional views taken along section
lines 1-1 and 2-2 of Figures 4 illustrate the variation in the height of the projection
100 along its length. Specifically, the maximum height of the projection is obtained
in proximity to the point of attachment of the intermediate section 98 to the respective
connecting plates 96. The minimum height of the projection is reached in proximity to
the mid-point of the intermediate section 98 located between the connecting plates 96.
The height of the projection 100 varies uniformly along the length of the intermediate
section 98 between the highest and lowest points.
A pair of side flanges 104 are located at the outside edges of the intermediate
section 98 and extend substantially the entire length of the intermediate section 98.
The side flanges 104 project in the same direction as the projections 100 of theconnecting plates 96. Figures I and I illustrate the variation in the height of
the side flanges 104 along the length of the intermediate section 98. The lowestprojection of the side flanges 104 is reached in proximity to the point of attachment of
the ends of the intermediate section 98 to the connecting plates 96. The highest of
the side flanges 104 is reached in proximity to the mid-point of the intermediate section
3 0 98 located between the connecting plates 96. The variation in the height of the
pro section 102 between the minimum and maximum height varies uniformly along the
length of the intermediate section 98. The width of the intermediate section 98 is
uniform along its length. The projection 102 and the side flanges 104 function as a
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means for stiffening the attachment member to sufficiently increase the rigidity of the
member for avoiding any bending under compressive loads.
As an alternative to a single projection 100 extending the entire length of the
intermediate section, two small projections can be used with one projection being located
at each end of the intermediate section 98. When two small projections are used, the
extra metal that is not taken up in forming the projections in proximity to the midpoint
can be used for forming deeper side flange 104 in the central portion of the intermediate
section 98. Preferably, the depth of the side flange 104 is at least approximately 1/3
of the width of the intermediate section 98.
Chile the preferred use of the attachment member is to connect the upper and
lower wooden members 12 and 14 within a truss 10, it should be clearly understood
that the invention may be used to connect together spaced apart pieces of wood for
any use.
While the invention has been described in terms of its preferred embodiments, itshould be clearly understood that numerous modifications may be made thereto within
departing from the spirit and scope of the invention as defined by the appended claims.
