Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
WO 95126256 PCT/US95/03507
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RIVETABLE ELEMENT, ASSEMBLY, METHOD
OF ASSEMBLY AND RIVETING DIE
FTFT D OF '1'j~ ~~ON
This invention relates to self riveting elements or fasteners, such as screws,
bolts, nuts
and the like, wherein the rivetable element includes a shaft or barrel portion
and an integral
head portion having a riveting portion on the underside of the head portion,
adjacent the shaft
or barrel portion. The field of this invention also relates to riveting dies
having a central
opening which receives the shaft or barrel portion of the riveting element and
a riveting
portion adjacent the opening which deforms the sheet metal part or panel to
which the
riveting element is attached into the riveting portion of the fastener head.
Finally, the field
of this invention relates to methods of attaching riveting elements of the
type described to a
sheet metal part or plastically deformable panel.
This application claims priority to German patent application P 44 10 475.8
filed
March 25, 1994.
As described, the present invention relates to improved self riveting elements
or
fasteners having a shaft or barrel portion and an integral head portion which
may be
permanently affixed to a sheet metal part or panel by riveting. Elements of
this type are
previously known, wherein the shaft is generally threaded and introduced in a
pre-formed
hole in the sheet metal part. The head portion then bears on one side of the
metal part. The
sheet metal part or panel is then shaped in a setting operation, such that the
panel molds
physically into a small groove in the shaft of the element, directly adjacent
to the bearing
WO 95126256 PCT/US95103507
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surface on the underside of the head portion, thereby securing the element in
a sheet metal
part or panel. The underside of the head, adjacent the shaft, may include
radial ribs and the
panel is deformed over the ribs during installation, preventing relative
rotation of the
elements on the sheet metal panel. Such assemblies are frequently used in
industrial
production by the automotive and appliance industries to fasten another
component to the
assembly, which may consist of a second sheet metal part and fastener, such as
a nut. The
contact surface of the head portion is thus located on one side of the first
panel, opposite the
second fastening element, such that the sheet metal part is stressed by
compression between
the fasteners.
In practice, however, the previously known self riveting elements of this type
were
not securely attached to the metal part, such that the element commonly
loosened in shipping
or storage before assembly, particularly where the sheet metal part is
relatively thin as now
used by the automotive and appliance industries. It is not uncommon for the
riveting element
to become lost or assume an orientation in the panel which is unacceptable for
further
processing of the sheet metal part, as described above. The loosening of the
prior
self riveting elements of this type also sometimes resulted in inefficiency of
the intended
an6-rotafion means, such that the element will rotate as the nut is assembled
on the shaft
portion, before the nut is tightened on the bolt. These difficulties are a
particular problem
in automotive body construction and other applications where the head portion
of the riveting
elements are located in an enclosed cavity following installation, which is no
longer
accessible for repair. If the fastening element freely rotates in the panel or
is lost under
these conditions, the object being manufactured, such as an automobile, can no
longer be
finished in regular production, but must be repaired at substantial expense.
Obviously, these
problems should be avoided, if possible.
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Another problem, particularly with attaching a riveting fastener to thin sheet
metal
panels results from the fact that the anti-rotation ribs must have a certain
height; that is, the
height of the ribs from the contact surface on the underside of the head
portion must be
sufficient to prevent rotation. Where the sheet metal part is relatively thin,
the ribs dent the
panel to a degree such that the full strength of the sheet metal part is no
longer available,
which may lead to further problems.
Another disadvantage of self riveting male fastener elements of this type is
that the
small groove in the shaft portion which receives the panel material to prevent
pull-out is
difficult to make and thus unnecessarily increases the cost of the fastener.
Further, this
radial groove results in an undesirable reduction in the strength of the bolt
or screw fastener,
including its fatigue properties, resulting from the sharp edges and reduction
of the
cross-sectional area of the shaft portion of the element. Further, because of
the groove
dimensions, the element may also be insufficiently secured to the sheet metal
part,
aggravating the tendency of the element to loosen in the sheet metal part or
drop out, as
described above.
Thus, a primary object of the present invention is to provide a self riveting
element
of this type which can be manufactured and fixed to the sheet metal panel at a
relatively low
cost and wherein the risk of loosening or loss of the element out of the sheet
metal part is
reduced and preferably precluded. Another object is to provide a joint between
the
self riveting element and panel which is as strong as possible and a self
riveting element or
fastener which is suitable for attachment to thin sheet metal parts, including
nonferrous sheet
metal parts, such as aluminum or its alloys.
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SUMMARY OF TIIE INVENTION
The self riveting element or fastener of this invention includes several
inventive
features or elements which, in combination, result in an improved element and
fastener and
panel assembly, and reduces the cost of the assembly. As will be understood,
however, the
inventive features of this invention may also be used separately, particularly
where the
function of a particular feature is desired or the function of another feature
is not desired.
As described above, the self riveting element or fastener of this invention
includes a shaft
or barrel portion and an integral head portion which extends generally
transverse to the
longitudinal axis of the shaft or barrel portion and which provides an annular
contact surface
on the underside of the head portion adjacent the shaft or barrel portion. In
the preferred
embodiment, the contact surface includes a plurality of concave pockets or
closed fields
which are bounded by ribs extending outwardly away from the shaft portion. In
the most
preferred embodiment, the pockets include a bottom wall which extends radially
inwardly
toward the shaft portion and the ribs between the pockets extend
longitudinally along the
shaft portion. In the most preferred embodiment, the shaft portion further
includes at least
one radial depression or groove which is spaced from the plane of the contact
surface of the
head portion, preferably a distance equal to approximately the thiclrness of
the sheet metal
part or panel to which the riveting element is attached. This depression or
groove most
preferably extends spirally around the shaft portion and may be the groove of
the first thread
where the shaft or barrel portion is threaded.
This design makes it possible in riveting the element or fastener to the sheet
metal
part or panel to plastically deform the material of the sheet metal part by a
suitable die
arranged concentrically to the shaft into the concave, peripherally closed
fields or pockets
in the underside of the head portion and radially into the depression or
groove in the shaft
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2185807
portion with essentially no thinning of the sheet metal part. Further, the
self riveting element
or fastener of this invention prevents rotation of the fastener in the panel
without weakening
of the sheet metal part, thus avoiding the problems associated with the
projecting radial ribs
on conventional self riveting elements of this type. Further, because the ribs
between the
concave pockets extend longitudinally along the shaft portion, the anti-
rotation is achieved
not only through the material driven into the concave fields, but also by the
positive
connection between the longitudinal ribs on the shaft portion and the sheet
metal part. As
a result, the torque resistance of the fastener in the panel is considerably
improved. In
attaching the element to the panel, the sheet metal part is not unnecessarily
reduced in
thickness and the depression or groove in the shaft portion may be located
further away from
the underside of the contact surface of the head than would be possible with
the radial groove
according to the prior art, such that the depression can be more easily
formed. Further, the
shape of the depression or groove can be formed more cleanly than where the
groove is
located immediately adjacent the head as in the prior art, insuring that the
sheet metal will
IS be more fully deformed into the depression, thereby generating an improved
resistance to
push-off of the fastener and loss of the element from the sheet metal part, as
described
above.
Another advantage of the self riveting fastener element of this invention is
the location
of the longitudinal ribs and the radial depression or groove on an enlarged
portion of the
shaft adjacent the head. Owing to this design, the self riveting element is
weakened less by
the depression, allowing a more full utilization of the rated strength of the
fastener element
and an improvement of the fatigue properties of the element. Further, the
torque resistance
of the element in the panel is also improved. Of special importance, however,
is that the
flow performance of the sheet metal part material can be improved in the
attachment of the
CA 02185807 2004-09-13
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fastener to the panel. Preferably, the preformed or prefabricated hole in the
sheet metal part
has a diameter which enables the insertion of the shaft portion without
damage. The large
diameter portion of the shaft portion preferably has a diameter which is
slightly greater than
the opening or hole in the panel, such that the diameter of the hole is
enlarged during
installation of the self riveting element in the panel, which provides
additional material which
can be driven into the concave, peripherally closed fields or pockets in the
head and into the
radial depression in the shaft portion. It is also possible to comically
deform the sheet metal
part adjacent the hole in accordance with the disclosure of U.S. co-pending
application Serial
No. 343,724 filed November 22, 1994 . The shaft or barrel portion of the self
riveting
eiemept is then received through the conical opening, through the apex of the
conical-shaped
depression and the panel is then pressed that by driving the head portion
against the panel, ~
thereby making additional material available for forming a tight joint between
the element
and the sheet metal part.
The spiral depression or groove in the shaft portion can be formed by a
threaded
groove, namely a continuation of a threaded portion on the shaft of the self
riveting element.
In this manner, the depression is made in the same operation as whem the
thread is formed
or cut in the shaft portion. This leads to a considerable cost saving in the
manufacture of
the self riveting fastener element and also leads to a clean spiral
depression. If the
longitudinal ribs are formed on the shaft partion, adjacent the head, to the
smaller diameter
portion of the shaft during the thread rolling operation, which is preferred,
the depression
or groove can be readily deformed during the thread rolling operation, such
that all threads
end in the depression. Alternatively, however, it is possible for the ribs to
be formed after
the thread rolling operation in a separate step, for example, also in a thread
rolling operation.
In this case, the depression would be divided into several sections by the
ribs. Further, the
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relieved portion between the ribs extending along the shaft should not extend
into the
depression to avoid interference with the deformation of the panel into the
depression. An
exception would apply where the self riveting elements are used for attachment
of an
electrical terminal. In that case, the ribs could produce a desirable kerfing
effect in the
opening of the terminal, which could be beneficial to creating a good
electrical contact.
The spiral depression may represent one or two threads and may also be in the
form
of thread sections, especially where the depression is fashioned as a multiple-
start threading,
which would be useful for the rivetable element of this invention. The spiral
depression or
groove has yet another advantage as compared to a circular radial groove.
Following
installation after extended use, additional torque may be required to remove
the nut from the
shank portion of the stud because of contamination or corrosion. Such elevated
torque,
however, will result in forcing the riveting element against the sheet metal
part due to the
spiral shape of the depression, such that increased torque resistance is
provided. Although
a spiral groove is preferred for the reasons set forth above, it is also
possible to utilize a
circular groove or depression wherein the pitch of the depression is zero
degrees. This form
may be preferred wherein the shaft portion of the self riveting element is
unthreaded, such
as an axle journal. The depression or groove should, however, be spaced from
the underside
of the head, as described above.
As will be understood, the area of the enclosed fields or pockets relative to
the contact
area, may be selected for optimal torque resistance. Thus, it is possible to
use the
self riveting element of this invention in conjunction with softer metals,
including aluminum
alloy panels, which are being used increasingly in automotive applications. In
such
applications, the material of the self riveting element may be selected to
avoid galvanic
corrosion, wherein the self riveting element may be formed of an aluminum
alloy.
WO 95126256 - PCTIUS95I03507
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As described, the die member utilized for assembly of the self riveting
element of this
invention includes a bore which receives the shank or barrel portion of the
fastener and the
opening is preferably crowned to deform panel metal into the confined fields
or pockets in
the head portion of the element. As will be understood, the bottom surface of
the groove
in the underside of the head portion will depend upon the shape of the die
used. Further,
the self-riveting element may be a male fastening element, such as a screw or
bolt, or a
female element, such as a nut, wherein the shaft portion is replaced by an
annular barrel
portion.
The method of this invention thus includes forming a hole in the sheet metal
part by
punching, drilling or the like; inserting the shaft or barrel portion of the
self riveting element
through the hole in the sheet metal part or panel; then plastically deforming
the sheet metal
part material in the vicinity of the panel hole to at least partially fill the
pockets in the
underside of the head and radially inwardly into the groove or depression in
the shank or
barrel portion of the self fastening element.
Other advantages and meritorious features will be more fully understood from
the
following description of the preferred embodiments, the appended claims and
the drawings,
a brief description of which follows.
Figure 1 is a side elevation of one embodiment of the self riveting element of
this
invention, which is partially cross-sectioned for clarity;
Figure 2 is an end view of the self riveting element shown in Figure 1;
Figure 3 is an enlarged cross-sectional partial view of the self riveting
fastening
element shown in Figure 1;
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Figure 4 is a partial cross-sectional end view of Figure 3 in the direction of
view
arrows 4-4;
Figure 5 is a schematic illustration of an installation apparatus or setting
head of this
invention illustrating the first step of the method of installation of this
invention;
Figure 6 is a partial cross-sectional view similar to Figure 5 following
installation of
the self riveting fastening element shown in Figure 5;
Figure 7 is a detailed partial cross-sectional side view of the riveting die
shown in
Figures S and 6;
Figure 8 is a side partially cross-sectioned view of the self riveting
fastening element
shown in Figures 1 to 4 installed in a sheet metal part;
Figure' 9 is an enlarged partial cross-section view of Figure 8 in the area
indicated by
reference 9;
Figure 10 is a side partially cross-sectioned view similar to Figure 1 of a
second
embodiment of the self riveting fastening element shown in Figure 1, wherein
the shank
portion of the riveting element is unthreaded;
Figure 11 is an end view of the fastening element shown in Figure 10;
Figure 12 is a partial cross-sectional view of the riveting element shown in
Figure 10;
Figure 13 is an enlarged partially cross-sectional view of Figure 12;
Figure 14 is a side partially cross-sectioned view of another embodiment of
the
self riveting element of this invention in the form of a female element;
Figure 15 is an end view of the self riveting element shown in Figure 14;
Figure 16 is an enlarged partially cross-sectioned side view of the fastening
element
shown in Figure 14;
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Figure 17 is an end partially cross-sectioned view of Figure 16 in the
direction of
view arrows 17-17;
Figure 18 is a partially cross-sectioned side view of another embodiment of
the
self riveting element of this invention in the form of a threaded female
fastening element
installed in a panel; and
Figure 19 is an enlarged view of the fastening element shown in Figure 18.
DETAILED DESCRPTION OF THE P FFF RFD FMRn IMENT~
Figure 1 is a side elevation of one embodiment of the rivetable element 10 of
the
invention in the form of a threaded bolt having a head portion 12 and a shaft
portion 16
which is externally threaded at 14. As shown in further detail in Figures 2, 3
and 4, the
underside 18 of the head portion 12 has a concave contact surface including
peripherally
closed fields or pockets 20 which are partly bounded by ribs 22 which extend
radially
outwardly from the shaft portion 16 as shown in Figures 2 and 4 and which are
continuous
with rib portions 24 which extend axially along the shaft portion 16 as shown
at 24 in Figure
3. As shown, the ribs 24 extend from the head portion to 26 to depression or
groove 28
which in the disclosed embodiment is the first spiral groove of the threaded
portion 14 of the
shaft.
As shown in Figures 2 and 4, the closed fields or pockets 20 are bounded on
their
radial outer side by surrounding annular peripheral surface 30 of the head,
with the ribs 22
defining the radial surface which is continuous with the annular surface 30.
The radial inside
of the pockets 20 are defined by a cylindrical peripheral surface 32 of the
shaft portion. As
shown in Figure 3, the rib portions 22 extend obliquely to the plane 31
defined by the
underside of the head portion 12 or backed-off from this plane (31) such that
the ribs do not
protrude from this backed-off plane adjacent the shaft portion of the self
riveting element.
WO 95126256 PCTIUS95I03507
11
It will be understood, however, that the rib portions 22 may be located in the
same plane 31
as the peripheral surface 30. The peripheral surface 30, as well as the
surfaces adjacent the
shaft 22, form the actual contact surface of the head portion 12. In this
embodiment, the
closed fields or pockets 20 are generally quadratic or rectangular which, in
practice, is a
favorable shape. It will be understood, however, that the pockets may be
shaped differently
within the purview of the present invention. With the embodiment disclosed in
Figures 2 and
4, the rib portions 22 in the contact area of the underside 18 of the head
portion 20 expand
radially outwardly as shown in Figures 2 and 4. Further, the rib portions 22
extend
continuously and without interruption into the outer peripheral surface 30 of
the head portion.
In the disclosed embodiment, there are eight rib portions 22, with the
preferred number of
rib portions ranging from between six and eight.
As evident from Figures 1 and 3, the pockets or closed fields 20 have their
greatest
depth measured axially in the direction of axial line 35 (in Figure 1)
adjacent the shaft
portion 16. The contact surface on the underside 18 of the head 12 comprises
primarily the
rib portions 22 and the peripheral outer surface 30. The bottom surfaces of
the pockets 20
can be used as a contact surface through deformation of the sheet metal part
into the closed
fields or pockets. The contact surface is thus relatively large, such that the
rivetable element
10 may be used with relatively soft sheet metal parts without concern that a
critical surface
pressure will result. In the most preferred embodiment, the bottom surfaces of
the closed
fields are located on a conical shell surface with an inscribed angle of
preferably betw~n
about 130° to 140°. This taper angle is referred to in Figure 3
as angle a. Thus, the
rivetable element 10 of the embodiment shown in Figures 1 to 3 features a
centering
depression which assures a high-quality, valuable guidance of the element. A
conical pilot
point 36 at the end of the shaft portion 16 not only provides a female
fastener or nut received
WO 95126256 PCTIUS95/0350~
2185807
12
on the shaft portion with a lead-in, but also guides the self riveting element
in the setting
head as it is inserted into the sheet metal part, as described below.
The setting or assembly operation is schematically illustrated in Figures 5
and 6. The
installation tool 40 shown in Figure 5 includes a setting or installation head
38 having a press
joining punch 42 movable in the direction of arrow 43. Arrow 42 indicates the
feed direction
of the self riveting element 10 in the installation head. The self riveting
elements 10 are fed
individually to the installation head 38. The self riveting element 10 shown
in Figure 5
proceeds under gravity, compressed air or the joining punch 42 through bore 44
of the
installation head until the head portion 12 of the element contacts the ball
48, which is
resiliently biased into the bore 44 by spring 46. In practice, three spring
biased balls are
provided arranged at intervals of 120° around the longitudinal axis 50
of the installation head
38. In the station of Figure 5, the prepunched sheet metal part 52 into which
the element
10 is to be installed is retained between the installation head 38 and a
riveting die member
54 of a lower tool 56. The shaft portion 16 of the self riveting element 10 is
provided with
a threaded portion 14 which is partially received through the preformed hole
in the sheet
metal part and through a coaxially aligned cylindrical centering hole 60 in
the riveting die
54. The riveting die 54 is releasably retained within a bore 57 of the lower
tool 56 and bears
against a bolster 59 on a lower press plate 61.
In the subsequent station of the setting operation, the press/joining punch 42
provided
in the installation head 38 moves further downwardly, forcing the head portion
of the element
past the spring loaded balls 48. During this motion, the surrounding crown
area 64 shown
in Figure 7 of the riveting die is forced into the material of the sheet metal
part deforming
the sheet metal into the V-shaped groove 23 which includes the enclosed fields
or pockets
20 and into the recess 28, thereby creating a secure, riveted joint between
the riveting
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element 10 and the sheet metal part 52, forming a secure assembly. The
preferred
embodiment of the riveting die 54 includes a crown area 64 which surrounds the
hole 58 as
shown in Figure 7. That is, the annular crown-shaped area of the riveting die
defines a wavy
end face with peaks 72 and valleys 74 extending in axial direction. In the
operation, the
relief peaks 72 deform and drive the material of the sheet metal part into the
concave fields
or pockets 20 in the underside 18 of the head portion of the element, while
the valleys 74
make contact with the sheet metal part opposite the ribs 22 which extend
radially outwardly,
such that there is no pronounced thinning of the sheet metal part in the area
of the ribs.
Because the sheet metal material is deformed between the riveting die and the
underside of the head portion 12 of the element 10, the sheet metal material
is also forced
to flow into depression 28, thereby forming the desirable positive joint.
Unexpectedly, it is
not necessary to angularly align the element 10 on the peaks and valleys of
the crown portion
64. because the element will rotate to assume a position in which the peaks 72
of the riveting
die 54 are aligned with the concave fields or pockets 20. That is, the
necessary alignment
takes place through a slight automatic twist of the element during the
installation operation.
A groove 80 is formed in the sheet metal part 52 by the crowned area 64 of the
die
member 54 as shown in Figures 8 and 9. This groove 80 may be interrupted, but
extends
around the shaft portion 16 of the self riveting fastener on the side of 71 of
the sheet metal
part away from the head 12 of the fastener as shown in Figures 8 and 9. As
will be
understood, this groove 80 features a wavy bottom surface; however, the peaks
of the wavy
bottom surface should not protrude beyond the underside 71 of the sheet metal
part in order
to provide a clean seating of the nut or other object to be attached to the
sheet metal part.
An exception is where the object to be attached to the sheet metal part is an
electrical
terminal. In such case, the peak areas of the wavy bottom surface may protrude
beyond the
WO 95126256 PCTIU595103507
14
underside 71 of the sheet metal part to provide a greater contact surface
pressure on the
terminal, providing a better electrical contact.
As will be understood, the self riveting element of this invention may be a
female
fastener, such as a nut, or any other type of element which may be permanently
attached to
a sheet metal part, such as a metal panel used by the automotive and appliance
industries.
Figures 10 through 13, for example, illustrate an element 110 in the form of
an axle journal.
Because of the similarities of the element 110 with the self riveting element
l I0 discussed
hereinabove, similar reference numbers are used for the element 110 shown in
Figures 11
and 12 and for all further embodiments described hereinbelow to avoid
unnecessary
duplication of description.
The differences between the axle journal 110 shown in Figures 10 through 13
and the
dread bolt 10 are not very significant. Major differences are found in two
areas. First, the
shaft portion 116 of element 110 includes a cylindrical bearing surface 115,
such that the
shaft portion is not threaded. It will be understood, however, that the
cylindrical bearing
surface 115 may include a threaded section in order to tighten the sheet metal
part with an
appropriate nut or nut and washer arrangement between the head portion 112 and
the nut or
to secure an interior bushing of the object mounted on the axle journal
against axial shifting
in a longitudinal direction of the element.
Second, the groove 128 into which the sheet metal is deformed is an annular
groove,
rather than a spiral groove thread as groove 28 in Figure 3. The annular or
circular groove
128 may thus be considered as a spiral groove with an angle of inclination
equal to zero
degrees. From Figure 12, it can be seen that this surrounding groove 128 is
arranged
approximately an equal distance to the sheet metal thickness from the contact
surface 118 of
the head 112 and that this distance is substantially greater than similar
grooves provided in
WO 95/26256 PGTlC1S95/03507
is 2185807
the fastening elements disclosed in the prior art. It is thus easier to form
the groove or
depression in the shaft portion than where the groove is located immediately
adjacent the
head portion 112 as disclosed in the prior art. As described above, however,
the groove 128
may be formed as a thread groove as shown at 28 in Figures 1 through 4. The
groove 128
is formed in this embodiment in the bearing area of the shaft portion adjacent
the head
portion 112 which may be possible and preferred with the element shown in
Figures 1 to 9.
The positive joint between the element 110 and a sheet metal part accomplished
exactly as
described above in regard to Figures 8 and 10 with the threaded bolt 10.
The riveting element of this invention may also be in the form of a female
element,
such as the bearing bushing 210 shown in Figures 14 to 17 and the nut fastener
310 shown
in Figures 18 and 19. The bearing bushing 210 shown in Figures 14 to 16
includes an axial
through-bore 282 having a cylindrical center portion 282 which provides the
bearing surface.
In Figure 14, the upper portion of the bore 282 includes a centering hole 234
having a
diameter somewhat larger than the bearing surface 282. The lower portion of
the bore 284
includes an enlarged diameter portion 286 which serves to prevent deformation
of the shaft
portion of the nut due to plastic deformation of the sheet metal part into the
fields or pockets
220 and the depression 228, which would result in constriction of the
cylindrical bore 282,
which would prevent the bearing part from being inserted in the element 210.
In this
embodiment, the head portion is a radial flange 212 and the shaft portion is
an annular barrel
portion 216. As set forth above, similar elements are numbered as described
above in regard
to Figures 1 to 13.
As shown in Figures 18 and 19, the riveting element 310 may be provided with
an
internal thread 388, such that the element 310 may be used as a nut fastener
following
installation in a metal part 352, as shown. This embodiment is very similar to
the bearing
WO 95I2G256 ~ ~ ~ ~ ~ PCTIUS95/03507
16
bushing 210 shown in Figures 14 to 17, except that the bore 388 is threaded.
The head
portion 312 is in the form of a radial flange portion and the shaft portion
316 is a tubular or
annular barrel portion which includes a radial depression. It will be
understood, however,
that the annular barrel portion may also be extended and externally threaded.
The threaded
bore 388 may then receive a threaded screw (not shown) to attach a further
object or element
to the metal part 352. When using a female element 310 according to Figures 18
and 19,
a cup-shaped depression 392 may be preferred in the sheet metal part 352,
which allows
flush mounting of an object on the underside 371 of the sheet metal part. This
cup-shaped
depression 392 may be created in the sheet metal part 352 either by a
preceding operation
as the sheet metal part is being punched or by a special shaping end face of
the riveting die
shown in Figures 5 and 6 as will be understood by those skilled in the art.
The female
riveting elements shown in Figures 14 to 19 may be attached to a metal part by
the
installation apparatus shown in Figures 5 and 6, as described above.
As will now be understood, the self riveting element and method of
installation of this
invention may be utilized for a broad range of applications, including male
and female
elements, fasteners and the like. Further, the several improvements disclosed
herein may
be used in combination or separately to produce an improved element and
fastener assembly.
For example, the peripherally closed fields or pockets (20, 120, etc.) provide
anti-rotation
means for the fastener assembly. Thus, the pockets may not be utilized in a
fastener
assembly where anti-rotation means is not desired. The method of this
invention may then
include forming a hole through the panel having a diameter greater than the
stud or barrel
portion of the elements, supporting the panel on a die assembly having an
opening coaxially
aligned with the panel hole configured to receive the stud or barrel portion
of the fastening
element, but having a diameter less than the head or flange portion of the
bearing surface,
~WO 95126256 PCTlUS95103507
~ 1~ 2185807
wherein the die member includes a projecting annular lip coaxially aligned
with the groove
in the riveting element. In the preferred embodiment, the groove 23 is
generally V-shaped
and extends into the flange or head portion of the element adjacent the barrel
or stud portion,
as shown in Figure 3. The method then includes inserting the stud or barrel
portiom of the
element through the panel hole into the die member opening, receiving the head
or flange
portion bearing surface against the panel, adjacent the panel opening. The
method then
includes driving the bearing surface of the element against the panel, causing
the die member
annular lip to substantially simultaneously deform the panel metal into the
axial groove and
radially into the radial groove of the element. In the most preferred
embodiment, the radial
groove is the first thread of a threaded portion of the fastener, such as
shown in Figure 3;
however, the groove may be annular as shown at 128 in Figure 10. The element
and metal
part or panel assembly thus includes a self riveting element, as disclosed,
and a metal part
or panel, wherein the stud or barrel portion of the element is received
through an opening
or hole in the metal part or panel and the panel or metal part is deformed
into both the V-
shaped annular groove which surrounds the stud or barrel portion and into the
radial groove
in the stud or barrel portion. In the most preferred embodiment, the panel
portion is further
and simultaneously deformed into the circumferentially spaced confined fields
or pockets,
forming a very secure assembly which prevents pull-out and rotation of the
self riveting
element in the panel. In the most preferred embodiment, the self riveting
element is a
fastener which may be utilized to attach a second element to the panel. In the
embodiment
10 disclosed in Figures 1 to 4, the fastening element is a male fastening
element, such as a
screw or bolt 10. In the embodiment 110 shown in Figures 10 to 13, the
fastening element
110 is an axle journal, wherein the cylindrical stud portion 15 receives a
female member
having a cylindrical bore, which is attached to the stud portion of the
fastening element. In
WO 95126256 PCTIUS95103507~
I8 2105307
the embodiment 210 disclosed in Figures 14 to 17, the fastening element 210 is
a bearing
bush which receives a male element having a cylindrical surface which is
received in the bore
82 of the bushing. Finally, in the embodiment 310 shown in Figures 17 and 18,
the
fastening element is a nut fastener, which receives a screw or bolt for
attachment of an
element to the panel. Having described the preferred embodiments of the
riveting element,
method of attachment and assembly of this invention, it will be understood by
those skilled
in the art that various modifications may be made to the disclosed embodiments
within the
purview of the appended claims, which follow.
