U.S. patent application number 10/843853 was filed with the patent office on 2005-11-17 for steel truss fasteners for multi-positional installation.
Invention is credited to Belinda, Richard L., Chapman, David A..
Application Number | 20050252152 10/843853 |
Document ID | / |
Family ID | 35308071 |
Filed Date | 2005-11-17 |
United States Patent
Application |
20050252152 |
Kind Code |
A1 |
Belinda, Richard L. ; et
al. |
November 17, 2005 |
Steel truss fasteners for multi-positional installation
Abstract
The invention is directed generally toward a fastener for use in
assembly of steel truss members which can be installed at an
angular orientation relative to the truss member surface. The
fastener comprises a shank having a tip and a head. The fastener
shank further has threaded portions for engaging truss members and
plate elements if present. The tip of the shank can have a
self-tapping point. The head of the fastener has a tool engagement
surface and a seating surface. The seating surface has a
configuration that allows for a wider distribution of force at a
truss assembly contact point. In particular, the configuration
includes an arcuate contour that is generally convex.
Inventors: |
Belinda, Richard L.;
(Westfield, MA) ; Chapman, David A.; (Easthampton,
MA) |
Correspondence
Address: |
ALIX YALE & RISTAS LLP
750 MAIN STREET
SUITE 1400
HARTFORD
CT
06103
US
|
Family ID: |
35308071 |
Appl. No.: |
10/843853 |
Filed: |
May 12, 2004 |
Current U.S.
Class: |
52/690 |
Current CPC
Class: |
F16B 25/103 20130101;
F16B 35/06 20130101; F16B 5/0275 20130101; E04C 3/11 20130101 |
Class at
Publication: |
052/690 |
International
Class: |
E04B 001/32 |
Claims
1. A truss fastener for multi-positional installation comprising: a
head and a shaft having a center axis extending between a tip and
the head, said shaft having a first threaded portion and a second
threaded portion, said first threaded portion being proximate the
tip, and said second threaded portion being proximate the head, the
head having a top surface, a tool engagement surface, and a lower
surface, the lower surface having an arcuate contact surface which
extends between the shaft and an edge of the head.
2. The truss fastener for multi-positional installation of claim 1
wherein the arcuate contact surface has arcuate portions from about
50 to about 25.degree. relative to the shaft center axis.
3. The truss fastener for multi-positional installation of claim 1
wherein the arcuate contact surface has an arcuate portion
proximate the edge of the head of about 20.degree. relative to the
shaft center axis.
4. The truss fastener for multi-positional installation of claim 3
wherein the arcuate contact surface has an arcuate portion
proximate the edge of the shaft attachment of about 10.degree.
relative to the shaft center axis.
5. The truss fastener for multi-positional installation of claim 1
wherein the first and a second threaded portions are buttress
threads.
6. The truss fastener for multi-positional installation of claim 1
wherein said arcuate contact surface is axially symmetrical about
said center axis.
7. A truss fastener and truss member arrangement comprising: a
shaft having a center axis extending between a tip and a head, said
shaft having a first threaded portion and a second threaded
portion, the head having a top surface, a tool engagement surface,
and a lower surface defining an arcuate contact surface, said
arcuate contact surface extends between the shaft and an edge of
the head; and a truss member having a first surface, said truss
member engaged with the first threaded portion and the second
threaded portion such that the center axis of the shaft is at an
angle oblique to the first surface, and said first surface is in
contact with a portion of the arcuate contact surface.
8. The truss fastener and truss member arrangement of claim 7
wherein the arcuate contact surface has arcuate portions from about
50 to about 25.degree. relative to the shaft center axis.
9. The truss fastener and truss member arrangement of claim 7
wherein the arcuate contact surface has an arcuate portion
proximate the edge of the head of about 20.degree. relative to the
shaft center axis.
10. The truss fastener and truss member arrangement of claim 7
wherein the arcuate contact surface has an arcuate portion
proximate the shaft of about 10.degree. relative to the shaft
center axis.
11. The truss fastener and truss member arrangement of claim 7
wherein a portion of the arcuate contact surface defines an arcuate
pathway between the shaft and the edge of the head such that about
10% of the arcuate pathway is in contact with the first
surface.
12. The truss fastener and truss member arrangement of claim 11
wherein portions of the arcuate pathway have an angle from about 50
to about 25.degree. relative to the shaft center axis.
13. The truss fastener and truss member arrangement of claim 7
wherein said first threaded portion is a buttress thread and is
proximate the tip, and said second threaded portion is a buttress
thread and is proximate the head, said second threaded portion
being engaged with a portion of the first surface of the truss
member and said first threaded portion being engaged with a portion
of a second surface of the truss member.
14. The truss fastener and truss member arrangement of claim 7
wherein a plate is interposed between the arcuate contact surface
and the truss member first surface.
15. The truss fastener and truss member arrangement of claim 13
wherein said first threaded potion is further engaged with a
plate.
16. A truss assembly comprising: a chord member having opposite
first and second walls defining a longitudinally extending channel,
said first and second walls having first and second openings,
respectively, said second opening being substantially radially
oblique said first opening; a tubular member disposed in said
channel, said tubular member defining a longitudinally extending
cavity and having third and fourth openings, said third and fourth
openings being aligned with said first and second openings,
respectively; a fastener comprising: a head comprising a top
portion and an underside disposed adjacent said chord member, said
underside having a symmetrically arcuate configuration; and a shaft
integrally extending from said underside through said first and
third openings, said cavity, and said fourth and second openings,
and terminating at a distal tip, said shaft comprising a proximal
portion having a thread, a distal portion having a thread, an
unthreaded shaft portion intermediate said proximal and distal
portions, and self-drilling means adjacent said distal tip allowing
self-drilling into said chord member and said tubular members;
wherein said thread of said proximal portion engages said chord
member and said tubular member adjacent said first and third
openings, said shaft portion is disposed in said cavity, and said
thread of said distal portion engages said chord member and said
tubular member adjacent said second and fourth openings.
Description
FIELD OF THE INVENTION
[0001] This invention relates generally to fasteners used in the
construction arts, and in particular, to steel construction
utilizing fastener connected truss members.
BACKGROUND OF THE INVENTION
[0002] Trusses and girders have long been used in construction for
spanning distances in industrial and residential buildings. Steel
trusses are now frequently used for the support of roof structures
due to their advantageous physical properties. In general, trusses
are constructed of truss members such as chords and tubular
members. The truss members are often joined together with
fasteners, such as bolts. Fastener joining is most common in medium
and large span truss assemblies.
[0003] The joining of the truss elements often involves complex
assembly that requires a high labor input to complete the truss
assembly. Typically, the assembly is accomplished through the use
of plates combined with bolts that pass through the truss members
and plates. The plates may be separate or may be integral to the
truss members. In some cases welding may augment or replace the use
of fasteners in joining together truss members. However, when
welding is utilized, the truss assembly typically must be flipped
over in order to complete the reverse side welds.
[0004] Conventionally, truss fasteners are designed to pass through
a first plate and penetrate through the truss member and into a
second plate. Fasteners such as those disclosed in U.S. Pat. No.
5,746,039 have a threaded section near the tip of the fastener and
a threaded section near the head of the fastener. In some cases,
the tip of the bolt or screw is configured to be a self-tapping
such that rotation of the fastener allows the tip to penetrate both
plates and truss members. One advantage to this fastener
configuration is that a truss can be assembled without a need to
turn the truss over such as when a screw or bolt is used on either
side of the truss assembly or when welding is utilized.
[0005] A significant problem arises when the truss fasteners do not
penetrate in strictly a perpendicular orientation to the surfaces
of the truss components. Conventionally, truss fasteners have a
head with a planar bottom surface which may also have a grooved
seating surface. When the conventional fastener is installed in
such an oblique angular orientation as described above, the planar
or grooved seating surface contacts the plate or structural member
at a very limited point of contact. Not only is this a relatively
weak point of contact, but there is also a concentration of force
at this limited point of contact.
SUMMARY OF THE INVENTION
[0006] The present invention in a preferred form is directed to a
device that addresses, among other things, the adverse consequences
which result from the oblique driving of a structural fastener. The
present invention is a fastener which comprises a fastener shank
having a tip and a head. The fastener shank further has threaded
portions for engaging truss members and plate elements if present.
The tip of the shank can have a self-tapping point. The head of the
fastener has a tool engagement surface and a seating surface. The
seating surface has a configuration that allows for a wider
distribution of force at a truss assembly contact point. In
particular, the configuration may include an arcuate contour that
is generally convex and is defined by a surface of revolution about
the central shank axis.
[0007] An object of the present invention is to provide a strong
contact interface between the seating portion of the fastener head
and the truss assembly regardless of the fastener installation
angle.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] Other objects and advantages of the invention will be
evident to one of ordinary skill in the art from the following
detailed description with reference to the accompanying drawings in
which:
[0009] FIG. 1 shows an upper portion of a steel truss fastener
consistent with the present invention.
[0010] FIG. 2A is a top view of a steel truss fastener consistent
with the present invention.
[0011] FIG. 2B is a side view of the steel truss fastener of FIG.
2A.
[0012] FIG. 3 shows the relative orientation of truss elements and
portions of a steel truss fastener at different installation
angles.
[0013] FIG. 4 shows the relative orientation of truss elements and
portions of prior art steel truss fasteners at different
installation angles.
[0014] FIG. 5 shows a truss assembly utilizing fasteners consistent
with the present invention.
[0015] FIG. 6 shows a cut away view of a fastener, chord, and
tubular member assembly consistent with the present invention.
[0016] FIG. 7 shows and enlarged fragmentary view, partly in
schematic, of a portion of the thread of a fastener consistent with
the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENT
[0017] Briefly stated, the invention in a preferred form is a steel
truss fastener which advantageously provides a connection of high
integrity even for an installation wherein the fastener is driven
at an oblique angle to the joined structural elements of a truss
assembly. With reference to the drawings wherein like numerals
represent like parts throughout the several figures, a steel truss
fastener in accordance with the present invention is generally
designated by the numeral 10.
[0018] The steel truss fastener 10 includes a head 12 integrally
attached to an elongated threaded shaft 14. The threading 16 of the
shaft 14 may be present along the entirety of the shaft or may be
interrupted so as to be present at only a portion or separate
portions of the shaft. For example, two portions of the shaft may
be threaded, as illustratively shown in FIG. 2B. For purposes of
further describing the invention, the shaft 14 includes a center
axis 18 which extends between the head and a tip 20 of the shaft
14.
[0019] In one embodiment of the invention the threading 16 is of
the buttress thread 58 configuration. The buttress thread 58
includes a support surface 86 and a driving surface 88. In a
preferred form, the support surface 86 is oriented at an angle of
approximately 10 degrees to a normal line N to the central axis 18
of the shaft 14. Preferably, the angle a between normal line N and
the support surface 86 is between about 0 degrees and about 15
degrees. The driving surface 88 is preferably oriented at an angle
of approximately 35 degrees to a normal line N to the shank axis
18. In preferred form, the angle of b between the normal line N and
the driving surface 68 is between about 25 degrees and about 65
degrees.
[0020] The head 12 in one embodiment of the invention has an upper
surface 22 and a lower surface 24. The lower surface defines a
contact surface 26 that is substantially arcuate in shape and
axially symmetric about axis 18. The arcuate contact surface 26 of
the head may be in the form of a continuous arc or may have angular
arcing portions of differing angles relative to the center axis 18
of the shaft 14. For instance, the angle(s) of arcuate contact
surface 26 relative to the shaft center axis 18 may range from an
angle that is about 0.degree. to an angle of about 25.degree.. The
arcuate contact surface 26 when in contact with a truss member 34
or plate 38 defines an arcuate contact pathway 28. The arcuate
contact pathway 28 is positioned between an attachment point 30 of
the head and an edge of the head 32 when the fastener 10 is
installed at an oblique angle. The arcuate contact pathway 28
includes a portion of the arcuate contact surface 26 that is in
contact with the truss member 34 or plate 38. This portion of the
arcuate contact pathway 28 may encompass a significant length of
the total arcuate pathway length. For example, the portion of the
arcuate contact pathway in contact with the truss member 34 or
plate 38 can be in the range of about 5% to over 90% of the total
arcuate contact pathway 28 length.
[0021] An example of a truss assembly 40 utilizing a fastener 10 is
illustrated in FIG. 5. The installed fastener 10 is illustrated in
FIGS. 5 and 6 in an installed position for securing together truss
members 34 such as a chord 42, defining a longitudinally extending
channel 62, and a tubular member 44 in a double shear interface.
The cord 42 has a first wall 46 and a second wall 48. The tubular
member 44 has a first wall 50 and a second wall 52. The fastener 10
may be installed by positioning the tip 20 adjacent the outside
surface of first wall 46 of the chord 42. The fastener 10 is
rotated such that the tip 20 drills an entrance hole 54 in the
chord first wall 46 and an entrance hole 56 in the tubular member
first wall 50. Following penetration by the tip 20, the thread 16
on a distal, lower portion 46 of the shaft 14 taps a complementary
thread in the walls of the entrance holes 54 and 56 thereby
threadably engaging the chord 42 and the tubular member 44. As the
fastener 10 is further rotated, the tip 20 drills an entrance hole
58 in the tubular member second wall 52 and an entrance hole 60 of
the cord second wall 48. Following penetration by the tip 20, the
thread 16 on a proximate, upper portion 47 of the shaft 14 taps a
complementary thread in the walls of the entrance holes 58 and 60
thereby threadably engaging the chord 42 and the tubular member
44.
[0022] In one embodiment of the invention, the fastener 10 engages
with the truss member 34 until the lower surface 24 of the head 12
reaches a first surface 36 of the truss member. The truss member 34
may form a multiple sided structure such as a square, rectangle, or
other geometrical shape. The truss member may therefore have a
second surface through which a portion of the fastener 10 may
penetrate. The fastener 10, as illustratively shown in FIG. 3,
engages the first surface 36 at an angle, for example,
approximately 0.degree. from perpendicular to the first surface 36
to approximately 20.degree. from perpendicular to the first surface
36. Upon contacting the surface of truss member the head due to the
shape of the head lower surface 24, contacts the surface along the
arcuate pathway 28.
[0023] In one embodiment plates 38 may be used on both sides of the
truss member 34 when joining truss members together. The plates 38
can be present to secure several truss members 34 together, such as
at a web of the truss assembly. A plate or plates may be present
intermediate that head arcuate contacting surface 26. For example,
a plate may be present in substantially parallel alignment with a
surface of the truss member. When the fastener is installed through
a plate 38 on the first surface of a truss member, a portion of the
arcuate contacting surface 26 contacts the plate substantially
parallel to the first surface of the truss member 34. It should be
understood that a second surface of the truss member 34 may or may
not be in substantially parallel alignment with the portion of the
arcuate contacting surface 26 depending on the configuration of the
truss member 34.
[0024] While the embodiments of the foregoing invention have been
set forth for the purpose of illustration, the foregoing
description should not be deemed a limitation of the invention
herein. Accordingly, various modifications adaptations and
alternatives may occur to one skilled in the art without departing
from the spirit and scope of the present invention. Accordingly, it
is to be understood that the present invention has been described
by way of illustration and not limitation.
* * * * *