Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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FASTENER
FIELD OF THE INVENTION
[0001] This invention relates to fasteners and more particularly to a fastener
that is
used to attach a laminar work piece to a metal substrate with the fastener
being inserted
through the utilization of an appropriate power tool.
BACKGROUND OF THE INVENTION
[0002] The present invention is an improvement over the fastener shown in U.S.
Patent No. 6,659,700 and the fastener disclosed therein is illustrated as
prior art in Figure 1.
The need for a self piercing construction fastener that can penetrate less
dense laminar work
piece materials (i.e. gypsum drywall, cementatious products, layered
fiberglass and the like)
and connect them to supporting walls of metal substrate framing (such as
studs) made from
light gage metal is well known. Such fasteners include a holding and clamping
member that
has resiliency and can move along a plane or between planes during the metal
penetration
process, and then return to its original form, thereby creating a combined
friction and
mechanical lock. Various designs of a laminar-to-metal-studs wall-fastening
member have
been in existence for a number of years, An advanced type is described in U.S.
Patent No.
6,659,700 as shown in FIG 1. It comprises a fastener with a head 10 bent over
at or near
ninety (90) degrees; a flat elongated body 12 containing at least one,
thinned, resilient tine 14
disposed within a void 15 in the body and twisted at an angle to the plane of
the fastener
body; small, equally spaced, equally formed teeth 16 upon the edges of the
tine 14; and a
sword-like point 18, all made from one-piece of thin sheet metal. After
insertion, via velocity
produced by a power tool, the fastener body and tine follows the point through
the less dense
work piece material and then through a hole in the metal substrate opened by
the point. The
toothed-tine, meeting the resistance of the substrate metal stud, rotates to a
near flatness,
parallel to the body plane. After passing through the metal substrate, the
toothed-tine rotates
back nearly to its original form, causing the teeth to produce a mechanical
lock on the
underside of the metal substrate.
[0003] The ability of the fastener to penetrate the bottom metal stud and its
withdrawal
resistance from the metal stud depend to a large degree on the material used
to form the
fastener. Thus it is desirable to employ thin sheet metal of high strength,
such as for example,
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spring steel metal or the like. To facilitate manufacturing, it would be
desirable to use a soft
malleable material which can be easily shaped, cut and folded with
conventional dies.
However, such a product, lacking sufficient carbon, cannot be strengthened
sufficiently by
heating and quenching, then tempering. Any process using less than high
strength (spring
steel) would not allow sufficient integrity of the thin fastener body to
resist bending.
Additionally, the tine essentially being a torsion spring requires a material
that retains the
resiliency of this component hence spring steel must be used.
[00041 Conventionally, with this type of fastener, a head is formed by bending
over
material from the top of the fastener body into some form. Fastener inventions
incorporating
such heads are formed within a stamping operation via bending. The head may be
a T, L or U
shape, but all are created by the bending process. These forms generate sharp
edges along at
least two sides (the nature of bending to form a head from flat metal). These
sharp edges cut
through the top layers of less-dense laminar work pieces, thereby eliminating
this head style
from industry accepted standards. It has been found that a fastener head
formed from bent-
over tabs the thickness of the fastener material are unsuccessful in the
softest laminar work
pieces such as gypsum drywall. The head, whether facing in one direction or in
opposing
directions, has sharp edges along all three sides and cut through the gypsum
drywall top
laminar work piece paper layer, thereby causing this form of a head to be
unacceptable in the
industry. Even if multiple layers of fastener material are bent over
themselves, forming a
radius at their furthest extension are used, the edges of the head still
contain ninety-degree
edges of such sharpness to cut the top paper layer of the drywall material.
[00051 Another problem with prior art, self piercing fasteners made from one-
piece
metal is the sword-like design of the point. It has been found that when a
self-piercing point
penetrates a metal substrate, current sword-style points deflect the substrate
away from the
material being attached to such a degree that the plasticity (memory) of the
metal has been
exceeded. Therefore, the metal cannot return to its original form and,
consequently, a gap
forms between the metal stud and the work piece material being fastened to the
stud. This
results in a loose and industry-unacceptable fastening joint. It has been
discovered that this
occurs when any style point widens the penetrated slot to the width of the
fastener body in
one continuous operation.
[0006] Another problem with prior art, self-piercing fasteners made from one-
piece
metal and containing a resilient, twisted tine is the area of attachment
between fastener body
and tine. If the tine connection is of substantial width and the moment of
bending is near the
attachment area, this area can experience tearing or fracturing of the
attachment area due to
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forces of torque applied during the installation process, thereby destroying
the integrity of the
tine.
[0007] Another problem with the prior art invention of a self-piercing
fastener with a
toothed tine is that, on occasion, thinner substrate metals (thinner than 25
gage) and softer
metals (i.e. aluminum) do not provide the stiffness or resistance to properly
unwind the tine.
Hence, the toothed tine either saws or rips through the metal substrate
thereby removing
material from the formed opening or slot at precisely the point where it is
required for an
individual tooth to accomplish a mechanical lock.
[0008] Another problem with prior art, self-piercing fasteners made from one-
piece
metal and containing a resilient, twisted tine with numerous, smaller, equally
spaced and
equally formed teeth upon the tine edges is that such teeth are unsuccessful
in allowing the
tine to properly function, and they do not properly lock under the bottom of
the metal
substrate. In prior art fasteners, the teeth were designed to be non-
discriminatory as to
thickness of work piece material being fastened to the metal stud. That is,
several different
thickness of work piece material (within a range) could be attached with the
same fastener
without regard to positioning of teeth along the tine. With numerous, small
teeth, it was
thought, any opposing two of the teeth would "catch" when the fastener came to
a stop. It has
been found that this does not occur. This design of tine teeth does not
provide a smooth
transition of the unwinding and then return (rotation) of the tine to the
nearly original position
when passing through the metal substrate pierced opening. Smaller teeth
beginning at or near
the bottom tine attachment do not allow proper unwinding, while these same
teeth upward on
the tine act as saw-teeth, cutting laterally into the metal substrate pierced
slot instead of
passing through the slot in an unwound position, thereby removing material
from the slot at
precisely the point where it is required for the individual tooth to provide a
mechanical lock.
Additionally, one tooth may be within the pierced hole created by the self
piercing point
when the fastener comes to a halt during installation. That tooth does not
allow the tine to
rotate back to nearly its prior position, and further does not allow the tooth
on the underside
of the metal stud to achieve a mechanical locking state underneath the bottom
of the metal
stud. Additionally, these smaller teeth provide insufficient bearing upon the
underside of the
metal substrate, required for maximum withdrawal resistance.
[0009] Another problem with prior art, self-piercing fasteners made from one-
piece
metal is that during secondary manufacturing processes of the fastener, the
fasteners can
clump or become intertwined, thereby disabling the ability to properly heat-
treat, plate and
collate fasteners, The area of greatest problem is when a fastener point
inserts itself
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substantially into the interior void surrounding the tine of another fastener.
With the prior art
fastener body thickness, the tine and void are of such diminutive nature, that
no process
allows the forming of anti-nesting devices from only profile stamping of
material existing
within the yet-to-be-stamped void.
[0010] Various forms of fasteners, some including metal penetrating capability
are
disclosed in the following prior art references:
Patent No. Inventor
1,338,988 Kinoshita
1,417,818 Frost
1,934,134 McChesney
2,110,959 Lombard
2,155,893 Fulton
2,168,854 Agnew
2,319,058 Hansman
2,353,579 Miller
2,382,474 Gambo
2,530,229 Clark
2,543,212 Waara
2,564,643 Hall
2,614,450 Oltz et al.
2,740,505 Flora
2,751,052 Flora
2,958,562 Jones
3,618,447 Gains
3,675,958 Duffy
3,800,653 Barth et al.
3,882,755 Enstrorn
3,973,295 Janke
3,983,779 Dimas
5,152,582 Magnuson
5,597,280 Stern
5,846,019 Kuhns
FRI.202.255
192,492 British Provisional Specification filed 1113/1921, accepted 02/05/1923
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There is thus a need in the industry for a self piercing metal fastener
constructed from a
single member of high strength metal which includes an integral head which
does not have
sharp edges and which will not cut the top paper layer of a drywall material,
which has a
piercing point which will incrementally and gradually form an opening in the
metal substrate
without deflecting the metal substrate beyond its range of elasticity, which
has an attachment
of a clamping and gripping member formed with the fastener which provides
greater rotation
of the gripping and clamping member without exerting stress forces causing the
attachment
area to tear or fracture, which includes spaced apart teeth on the gripping
and locking
member which will permit attachment of different sizes of work piece material
to a metal
substrate, and which will allow the formation of anti-nesting devices within
the fastener.
SUMMARY OF THE INVENTION
[0011] A one piece fastener made from high strength steel for securing a work
piece
to a metal substrate which includes an elongated substantially flat body
having first and
second ends and first and second oppositely disposed faces and first and
second side edges.
A crown formed from substantially symmetrical halves extending outwardly from
the first
and second faces of the body, a piercing tip formed at the second end of the
body for
incrementally generating an opening in the metal substrate and at least one
gripping and
clamping member on the body to lock the work piece and the metal substrate
together.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] FIG. I is a perspective view of a prior art fastener;
[0013] FIG. 2 is perspective view of the fastener of the present invention;
[0014] FIG. 3 is a front elevational view of a fastener constructed in
accordance with
the principals of the present invention;
[0015] FIG. 4 is a side view of the fastener shown in Figure 2;
[0016] FIG. 5 is a front elevational view showing the fastener of Figure 2 and
an
intermediate stage of construction;
[0017] FIG. 6 is a side view of Figure 5;
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[0018] FIG. 7 illustrates the progressive stamping which is utilized to form
the
fastener of the present invention;
100191 FIG .8 is a partial view of the fastener of the present invention
illustrating the
piercing point in greater detail;
[00201 FIG. 9 is a partial view of the fastener of the present invention
illustrating the
manner in which the clamping and the gripping member is formed with specific
reference to
the gripping teeth thereon;
[00211 FIG. 10 illustrates the fastener of the present invention attaching a
work piece
to a metal stud which is of a first dimension;
[00221 FIG. 11 illustrates attaching a work piece to metal substrate with the
work
piece being of a smaller dimension;
[0023] FIG. 12 illustrates the formation of anti-nesting members on the
fastener of the
present invention; and
[0024] FIG. 13 illustrates an alternative embodiment of the fastener of the
present
invention including a gripping and clamping member which extends substantially
the entire
length of the void provided to receive such clamping and gripping member.
DETAILED DESCRIPTION OF THE INVENTION
[00251 Referring to the drawings and more particularly to Figure 2 thereof,
there is
illustrated in perspective view the fastener 20 of the present invention. The
fastener 20
includes a flat elongated body 22 having a first 24 end and second end 26. The
body 22
includes a first flat surface or face 28 and second flat surface or face 30
which is on the
opposite side of the flat elongated body 22. The body also includes first side
edge 32 and
second side edge 34. Disposed adjacent the first end 24 of the body is a crown
37 which is
formed from first 36 and second 38 substantially symmetric halves extending
radially
outwardly from the first flat surface 28 and the second flat surface 30
respectively. There is a
piercing tip 40 formed at the second end 26 of the body 22 and there is a
clamping and
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gripping member 42 connected to the flat body 22 at each end of the clamping
and gripping
member 42. The gripping and clamping member 42 includes a first tooth 44 which
is formed
by reducing the width of the gripping and clamping member from and initial
root width as
shown at "W" to a smaller root width as shown at 46. Displaced upwardly toward
the crown
from the first tooth 44 is a second tooth 48 which extends upwardly and
outwardly from the
second root width 46. The teeth 44 and 48 are utilized to clamp work pieces of
different
width to a metal substrate. Additional details of the various components of
the fastener 20 as
illustrated in Figure 2 are illustrated in the remaining figures and will be
described in greater
detail herein below.
[0026] Figure 3 is a front elevational view of the fastener as illustrated in
Figure 2
and Figure 4 is a side view thereof. As is illustrated in Figures 3 and 4 the
symmetrical
halves 36 and 38 of the crown are interconnected by a first strap 50 and a
second strap 52
disposed at the first and second side edges 32 and 34 respectively of the flat
elongated body
22. The straps 50 and 52 are bent approximately 180 degrees at their
midsection as is
illustrated particularly in Figure 4 to cause the two symmetrical halves of
the crown to
become aligned so that they extend radially outwardly from the first and
second flat faces 28
and 30. As is also shown particularly in Figure 4, as well as the perspective
view of Figure 2,
the outer periphery of the first and second symmetrical halves 36 and 38 of
the crown are
arcuately shaped as shown at 54 to eliminate any sharp edges which would tend
to cut into
the surface of the wall board which would be fastened to a metal stud as above
described.
[0027] As is shown in more detail in Figure 3 the gripping and clamping member
42
is disposed within a void 54 formed substantially centrally of the flat body
22. The gripping
and clamping member is formed intregally with the body 22 and is connected at
its lower end
56 to the body 22 adjacent the second end 26 thereof but displaced from the
piercing tip 40.
The upper end 58 of the gripping and clamping member is connected adjacent,
but spaced
from the second end 24 of the body 22. The gripping and clamping member 42
also defines a
void 60 extending from substantially adjacent the connection at its lower end
56 upwardly
toward to a point adjacent the first tooth 44. As illustrated in Figures 2, 3
and 4 the gripping
and clamping member 42 is twisted or rotated so that the teeth 44 and 48
extend outwardly
from the first and second faces 28 and 30 of the body 22. The fastener of the
present
invention is formed from high strength material and preferably spring steel
and is thin, that is
formed in a manner such that it is thinner than the thickness of the body 22
so that it will tend
to move toward a flat position within the void of the body 22 when it is
inserted through the
metal substrate but when it comes to rest will return to the position as
illustrated in Figures 2,
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3 and 4 thereby clamping the work piece to the metal stud. By providing the
void 60 in the
gripping and clamping member 42 this twisting and untwisting of the gripping
and clamping
member is facilitated and also eliminates any tendency for the gripping and
clamping
member to break at its connection points 56 and 58 to the body.
[0028] Referring now more particularly to Figures 5, 6 and 7, a solution to
the
problem of head design described above is addressed by draw-forming the two
symmetrical
halves 36 and 38 of the head from the top portion of the material forming the
fastener body
with one-half a nearly mirror image of the other and placed above the other
half head as
shown in FIG. 6. If the entire head top surface is allowed to remain, it will
crack when bent to
position the head halves and the two head halves will break apart. The reason
the bend area
will crack is that it has become work-hardened during the deep-drawing
process. The solution
is a relief in the form of a void 62 as shown in Fig. 5 within the center
connection area.
However, the final outside area of the head has not been work-hardened, so two
connecting
straps or bands 50 and 52 on the sides of the head perimeter, which span this
void and hold
the two head-halves together during and after bend-over, maintain their
integrity without
cracking or breaking apart. The deep-drawing process is to form each head-half
in multiple
steps within the progressive-stamping process, each time moving the material
somewhat
closer to final form as shown at 64, 66, 68, 70 and 72 in Fig. 7. Each head-
half is formed
with a smooth outer arcuate rim 54. When the top head-half is bent over to
mate with the
other half there is need of attachment points between the two halves. After
bending over of
the top-head half a tab 74 attached to its bottom is press-fit into a mating
hole 76 within the
fastener body, thereby securing the fastener head-halves together.
Additionally, material in
the form of other tabs may extend from each side of the head-halves. Such
additional tabs can
be used to further anchor the bent-over, mating head to body via compression
(or "staking") a
substantial portion of the tab through mating holes within the body. After the
two halves of
the head are secured together, the two connecting bands may remain in their
bent-over
position (extending above the head) FIG. 3, or may be sheared off in another
step and swaged
together, now being flush with the head top.
100291 Referring now more particularly to Fig. 8, a solution for the problem
of
fastener point metal substrate or stud deflection described above is through
incorporation of a
point 78 that reduces this stud deflection during point penetration, thereby
allowing it
to return to its original form. Such a fastener point is a "step" point
because there are
multiple, upward steps to its form. The point begins with a narrow, angled
piercing point 80
with straight sides 82 and 84, stepping outward to progressively wider point
planes 86 and
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88. Each step has an angled transition 90, 92 from the last step to the next
wider step. The
transition may or may not be beveled as shown at 94, 96 for sharpness of
cutting. However,
after this transition between steps, the sides of each step are parallel to
the sides 32, 34 of the
fastener. Alternatively, the side edges of each step in the piercing point 78
may be slanted
inwardly toward the longitudinal axis 98 of the body as shown at 100, 102 and
allow the
metal substrate to return to its original position between steps of
penetration by the point. The
purpose of these steps is to allow penetration of the metal incrementally. The
angled and
narrow lead point introduces initial point penetration of the metal via
minimum width. Then
the sides of the point, parallel to the body or slanted inwardly, follow
through the hole created
by the initial penetration without causing any further deflection of the
metal. During this
millisecond "rest" period, two things have occurred: the metal substrate has
not been
deflected past its plasticity point and the metal substrate has time to return
to its original
position prior to further penetration of the point. After this penetration,
the hole is
progressively widened by the transition area to the next step. Penetration and
subsequent
forming of the hole in the metal substrate is incremental and progressive,
thereby avoiding
over-deflection of the metal substrate. The material is allowed to return to
its original form
and the fastening joint between the work piece and the metal substrate
maintains its integrity.
[00301 Referring now more particularly to Fig. 9, a solution to the problem of
the
clamping and gripping member tearing or cracking at its attachment point to
the body is
illustrated. This is accomplished by forming a void 60 within and slightly
above the
attachment area 106 upward toward the crown. This internal void 60 creates a
fork at the
attachment site, creating two legs 108, 110. When the clamping and gripping
member is
rotated during installation, these legs 108, 110 act as independent torsion
bars, twisting
different arcs and upon different planes. This reduces the stress upon the
attachment area 106
and eliminates the problem of failure of the body 104 attachment.
[0031] Referring now more particularly to Fig. 12, the problems incurred
through use
of numerous, small, equally spaced, equally formed gripping teeth is
successfully addressed
by providing only two or three teeth at pre-set distances from the fastener
head, with
distances of a smooth (no teeth) reduced clamping and gripping member root
between teeth.
The teeth, being of greater distance apart than those of the prior art, can
now be formed wider
and taller, thereby increasing their shear strength while providing greater
bearing surface
upon the pierced metal substrate underside, resulting in greater withdrawal
resistance. The
teeth are of different shape for the bottom tooth 44(thicker work piece) as
opposed to the
upper (thinner work piece) tooth 48. The bottom tooth 44 is made from the
largest width of
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the clamping and gripping member body 104 root area, then by cutting
perpendicular to the
sides of the body 104 into the vertical plane of the body 104, thereby
reducing body 104 root
width. The far outside 106, 108 of the subsequent opposing ledges forming the
teeth project
outward slightly from the body 104 root width, and upward, providing a slight
arc (cupped)
shape to the top of the tooth substantially perpendicular to the body 104
sides and a curved
terminus. This aids in directing withdrawal forces towards the ends of the
teeth. The upper
tooth 48 begins its bottom body 104 connection at the now reduced root 110
progressing
outward acutely to radius ends 112, 114 that turn inward nearly perpendicular
to the fastener
body 22 sides, until its connection with the body 104 root. This construction
of the tooth 48
also provides a slight are (cupped) shape to the top of the tooth
substantially perpendicular to
the body 104 sides and a curved terminus. The first tooth 44 to enter the
pierced hole within
the metal substrate is pre-set for a thicker work piece (i.e. 5/8" or 3/a") as
shown in Figure 10.
Being made from the largest body 104 root, it easily follows the clamping and
gripping
member into the pierced metal hole, beginning the unwinding (rotation) of the
gripping and
clamping member. If the fastener were to end installation when this tooth has
passed
underneath the bottom of the metal substrate, the reduced body 104 root
immediately above
this bottom tooth 44, and void of any teeth, allows successful return
(rotation) of the body
104 back nearly to its original position. If the upper, second tooth 48 is pre-
set for thinner
work piece (i.e. '/4" or 3/8") as shown in Figure 11, then the first, bottom
tooth 44 passes
through the pierced hole in the metal substrate, then the reduced body 104
root, and then the
acute angle of the second tooth 48 bottom encourages rotation of this second
tooth. The
radius ends of this second tooth aid in "finding" and passing through the
metal substrate
pierced hole. The top of this tooth 48 (perpendicular to the body edges) also
has a slight are
(cupped) shape. This aids in directing withdrawal forces towards the end of
this tooth 48.
This second style of tooth and reduced, smooth body 104 root can be replicated
above the
second tooth if an even thinner work piece is desired to be fastened. The
presiding rule,
however, is that the distance of the smooth, reduced body 104 root between
teeth must be at
minimum the distance of the metal thickness and the distance of the extruded
metal 116, 118
formed during point penetration as seen in Figs. 10 and 11.
[0032] A solution for the problem of fastener nesting is found through forming
anti-
nesting tabs 120, 122, 124 and 126 within the void 54 (FIG. 12). As
conventional tooling
used in progressive stamping requires a minimum thickness in order to maintain
its integrity
during the stamping process, a profile that would stamp the form of anti-
nesting tabs that
extended into the area of the void 54 is not currently viable. Therefore, the
tabs must be
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formed via thinning and extruding body material into the void area. Material
for this thinning
and extruding are not available from the clamping and gripping member as this
member has
already been thinned to such extent as to provide no further material.
Additionally, any
protrusion along the body 104 would impede its performance. These anti-nesting
tabs are
placed in such proximity as to successfully prevent the insertion of one
fastener head or point
into another during normal manufacturing processes such as heat treating,
tempering or
forming the fasteners into a continuous roll for insertion into the magazine
of a power tool.
[0033] In order to maximize the use of the fastener of the present invention
within
metals thinner than 25 gage and softer than steel (such as aluminum), a
toothed clamping and
gripping member of the type described above, with a void extended upward the
majority of
the distance of the body 104 length is shown in Fig. 13. The design of this
body 104 includes
a central void 128 creating two legs. When the body 104 is rotated during
installation, these
legs have greater "moment", act as independent torsion bars, twisting
different arcs and upon
different planes, providing greater resiliency, thereby properly rotating
within thinner and
softer materials.
[0034] There has thus been disclosed an improved one piece fastener made from
high
strength steel for securing a work piece to a metal substrate which overcomes
the problems of
prior art fasteners performing similar functions.
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