U.S. patent application number 14/126453 was filed with the patent office on 2014-05-08 for method for producing an attachment element.
The applicant listed for this patent is Pierre Auriol. Invention is credited to Pierre Auriol.
Application Number | 20140126978 14/126453 |
Document ID | / |
Family ID | 46508093 |
Filed Date | 2014-05-08 |
United States Patent
Application |
20140126978 |
Kind Code |
A1 |
Auriol; Pierre |
May 8, 2014 |
METHOD FOR PRODUCING AN ATTACHMENT ELEMENT
Abstract
The invention relates to a method for producing an attachment
element (R) comprising a shaft (100) having a first end provided
with a head (200) and a second end that is intended to be deformed
in order to form a button (300) providing a bearing surface
opposite the surface formed by the head (200), said shaft (100)
having a nominal diameter (D). The method is characterised in that
the element is sized such that the minimum length (L) of the shaft
(100) to be deformed to form the button (300) is no less than 1.25
times the nominal diameter (D) of the shaft (100). The invention is
suitable for use in the production of attachment elements, such as
rivets.
Inventors: |
Auriol; Pierre; (Flourens,
FR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Auriol; Pierre |
Flourens |
|
FR |
|
|
Family ID: |
46508093 |
Appl. No.: |
14/126453 |
Filed: |
June 20, 2012 |
PCT Filed: |
June 20, 2012 |
PCT NO: |
PCT/FR2012/051394 |
371 Date: |
December 16, 2013 |
Current U.S.
Class: |
411/501 |
Current CPC
Class: |
B21J 15/02 20130101;
F16B 19/06 20130101; B21K 1/58 20130101 |
Class at
Publication: |
411/501 |
International
Class: |
B21K 1/58 20060101
B21K001/58 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 20, 2011 |
FR |
1155363 |
Claims
1. Method for manufacturing, using a metal wire, a fastening
element such as that having a shank wherein a first end is equipped
with a head, the second end being intended to be deformed to act as
a knob forming a bearing surface to be positioned facing that
formed by the head, said shank having a nominal diameter, said
element being designed such that the minimum length of the shank
intended to be deformed to act as the knob is not less than 1.25
times the nominal diameter of the shank, characterized in that it
comprises obtaining, for the metal wire, a material grain adopting
a size of 6 or finer according to the criteria defined by the ASTM
E 112 standard, performing, on said wire, a work-hardening step
wherein the rate is greater than 30%, and designing said element
such that the minimum diameter of the knob obtained after deforming
the shank is greater than 1.75 times the nominal diameter of the
shank.
2. Method according to claim 1, characterized in that it comprises
designing said element such that the knob obtained after deforming
the shank has a maximum thickness (e) equal to 0.45 times the
nominal diameter of the shank.
3. Method according to claim 1, characterized in that said element
comprises a rivet.
4. Method according to claim 1, characterized in that it comprises
selecting, for the metal wire from which the element is formed, an
aluminum alloy wherein the additional elements to aluminum adopt as
a percentage the following proportions: TABLE-US-00004 min max CR 0
0.04 CU 2 2.5 FE 0.011 0.14 MG 2.04 2.3 MN 0 0.05 SI 0.02 0.12 TI
0.02 0.06 ZN 6.1 6.7 ZR 0.08 0.15.
5. Method according to claim 1, characterized in that it comprises
selecting, for the metal wire from which the fastening element is
formed, an aluminum alloy wherein the additional elements to
aluminum adopt as a percentage the following proportions:
TABLE-US-00005 min max CR 0.05 0.1 CU 2.6 3 FE 0.34 0.5 MG 0.33 0.5
MN 0.1 0.2 SI 0.32 0.8 TI 0 0.01 ZN 0.1 0.17 FE--MN 0.47 0.68
TI--ZR 0.05 0.15.
6. Method according to claim 1, characterized in that it comprises
selecting, for the metal wire from which the fastening element is
formed, an aluminum alloy wherein the additional elements to
aluminum adopt as a percentage the following proportions:
TABLE-US-00006 min max CR 0 0.03 CU 3.5 4.3 FE 0.016 0.3 MG 0.43
0.65 MN 0.41 0.63 SI 0.21 0.4 TI 0.005 0.08 ZN 0.002 0.04.
7. Method according to claim 1, characterized in that it comprises
of selecting a wire which does not have inclusions (isolated nicks,
abrasions, pitting, isolated minor inclusions, cold shuts,
non-continuous scratches, tool marks, burrs, etc.) greater than
0.15 millimeters in depth.
8. Method according to claim 1, characterized in that it comprises
selecting a wire wherein the depth of longitudinal continuous
defects does not exceed 40 microns.
9. Method according to claim 1, characterized in that it comprises
subjecting said element to a cooling step wherein the time for
transferring the fastening elements from one medium wherein the
temperature is equivalent to that of the solution treatment to a
medium wherein the temperature is 20 degrees Celsius is less than 5
seconds.
10. Method according to claim 1, characterized in that it comprises
subjecting said element to a quenching step wherein the temperature
variation during the quenching of the same batch of elements does
not exceed 5 degrees Celsius.
11. Method according to claim 1, characterized in that the
fastening element is designed such that the shank end radius is
proportional to the diameter of the shank itself according to a
proportion wherein said radius is equal to the nominal diameter of
the shank divided by a value ranging between 3 and 3.5.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to the field of fastening
elements such as rivets and particularly to adaptations for
enhancing the mechanical features thereof.
DESCRIPTION OF THE PRIOR ART
[0002] There are a plurality of rivets and manufacturing methods in
the prior art liable to have the mechanical features sought.
Nonetheless, the fatigue and tearing strength criteria applicable
to rivets are increasingly stringent.
[0003] However, while one solution to meet these criteria lies in
increasing the rivet dimensions, such an increase involves the
drawback of the appearance of cracks.
DESCRIPTION OF THE INVENTION
[0004] For this reason, the applicant conducted research aimed at
providing a solution for the most stringent criteria in respect of
the fatigue and tearing strength criteria, on one hand, and at
solving the technical problem of the appearance of cracks, on the
other.
[0005] This research resulted in the design of a method for
manufacturing, using a metal wire, a fastening element such as that
having a shank wherein a first end is equipped with a head, the
second end being intended to be deformed to act as a knob forming a
bearing surface to be positioned facing that formed by the head,
said shank having a nominal diameter. This fastening element is
designed such that the minimum length of the shank intended to be
deformed to act as the knob is not less than 1.25 times the nominal
diameter of the shank.
[0006] The invention is remarkable in that it consists of [0007]
obtaining, for the metal wire, a material grain adopting a size of
6 or finer according to the criteria defined by the ASTM E 112
standard, [0008] performing, on said wire, a work-hardening step
wherein the rate is greater than 30%, and [0009] designing said
element such that the minimum diameter of the knob obtained after
deforming the shank is greater than 1.75 times the nominal diameter
of the shank.
[0010] These features ensure that a knob and thus a fastening
element having a satisfactory fatigue strength are obtained.
[0011] Obtaining a finer grain requires additional working
operations on the material, rendering the wire production method
longer and more costly. In this way, for example, the proposed
work-hardening should be performed in a plurality of steps.
Furthermore, a suitable heat treatment should be used.
[0012] A person skilled in the art would not turn to such a
solution requiring more operations and control of these base wire
manufacturing operations before producing the rivet. A person
skilled in the art facing the same technical problem would prefer
to purchase a more expensive material such as titanium to obtain a
fastener having the same features.
[0013] According to one further particularly advantageous feature
of the invention, the knob obtained after deforming the shank has a
maximum thickness equal to 0.45 times the nominal diameter of the
shank. Such a thickness associated with the diameter defined above
makes it possible to obtain a fastening element meeting fatigue and
tearing strength criteria.
[0014] The invention also relates to the rivet having all or some
of the features described above.
[0015] In addition to the dimensional and grain features presented
by the wire selected for manufacturing the fastening element
according to the invention, further features suitable for obtaining
a fastening element meeting the criteria without involving the risk
of cracking, have also been devised.
[0016] Further features of the manufacturing method are
particularly based on the selection of the features of the wire
from which the fastening element is forged and the constituent
materials of said wire, which is subject to a method comprising
specific work-hardening steps, and the element obtained is subject
to a quenching step, etc.
[0017] This wire is an aluminum alloy wire which, in addition to
the aluminum (Al) compound, comprises additional elements such
as:
[0018] Chromium symbolized by CR, Copper symbolized by CU, Iron
symbolized by FE, Magnesium symbolized by MG, Manganese symbolized
by MN, Silicon symbolized by SI, Titanium symbolized by TI, Zinc
symbolized by ZN, Zirconium symbolized by ZR, etc. The proportions
described below are minimum or maximum percentages of the elements
alone or a combination of elements. These compositions are suitable
for taking on the sought mechanical properties for a fastener while
preventing the presence of cracks particularly due to the copper
content. They are also suitable for conducting the desired
work-hardening and thus obtaining the fine grain sought.
[0019] In this way, according to one particularly advantageous
feature, the manufacturing method according to the invention is
remarkable in that it consists of selecting, for the metal wire
from which the fastening element is formed, an aluminum alloy
wherein the additional elements to aluminum adopt as a percentage
the following proportions:
TABLE-US-00001 min max CR 0 0.04 CU 2 2.5 FE 0.011 0.14 MG 2.04 2.3
MN 0 0.05 SI 0.02 0.12 TI 0.02 0.06 ZN 6.1 6.7 ZR 0.08 0.15
[0020] According to a further particularly advantageous feature,
the method consists of selecting, for the metal wire from which the
fastening element is formed, an aluminum alloy wherein the
additional elements to aluminum adopt as a percentage the following
proportions:
TABLE-US-00002 min max CR 0.05 0.1 CU 2.6 3 FE 0.34 0.5 MG 0.33 0.5
MN 0.1 0.2 SI 0.32 0.8 TI 0 0.01 ZN 0.1 0.17 FE--MN 0.47 0.68
TI--ZR 0.05 0.15
[0021] According to a further particularly advantageous feature,
the method consists of selecting, for the metal wire from which the
fastening element is formed, an aluminum alloy wherein the
additional elements to aluminum adopt as a percentage the following
proportions:
TABLE-US-00003 min max CR 0 0.03 CU 3.5 4.3 FE 0.016 0.3 MG 0.43
0.65 MN 0.41 0.63 SI 0.21 0.4 TI 0.005 0.08 ZN 0.002 0.04.
[0022] The condition of the wire is also the subject of further
specific selections. For example, according to one particularly
advantageous feature, the method consists of selecting a wire which
does not have inclusions (isolated nicks, abrasions, pitting,
isolated minor inclusions, cold shuts, non-continuous scratches,
tool marks, burrs, etc.) greater than 0.15 millimeters in depth.
Furthermore, the method consists of selecting a wire wherein the
depth of longitudinal continuous defects does not exceed 40
microns.
[0023] A further feature of this method relates to the quenching
step. According to a technological choice, the method consists of
subjecting said element to a cooling step wherein the time for
transferring the fastening elements from one medium wherein the
temperature is equivalent to that of solution to a medium wherein
the temperature is 20 degrees Celsius is less than 5 seconds.
[0024] Finally, according to a further feature, the method consists
of subjecting said element to a quenching step wherein the
temperature variation during the quenching of the same batch of
elements does not exceed 5 degrees Celsius.
[0025] According to a further particularly advantageous feature of
the invention, the shank end radius of the fastening element, i.e.
the connecting radius between the cylindrical surface of the shank
and the plane surface of the shank end, is proportional to the
diameter of the shank itself according to a proportion wherein said
radius is equal to the nominal diameter of the shank divided by a
value ranging between 3 and 3.5.
[0026] A rivet having an association of these features in the
manufacturing method thereof is suitable not only for meeting
fatigue and tearing strength criteria but also for preventing the
presence of cracks.
[0027] A further feature helping obtain a crack-free fastener
consists of selecting, from the manufactured fasteners, a fastener
wherein the shank particularly at the part to be deformed, i.e. at
the shank end radius, does not have longitudinal continuous defects
greater than 40 microns.
[0028] It would thus appear that the invention consists of a series
of feature selections both upstream from the manufacture of the
fastening element for example in the choice of the features of the
base wire and downstream, i.e. not only in the final dimensions but
also in the final surface condition of the fastening element
obtained.
[0029] The invention thus also relates to the fastening element
obtained according to all or some of the features of the method
described above.
[0030] The fundamental concepts of the invention described above in
the most basic form thereof, further details and features will
emerge more clearly on reading the following description and with
reference to the appended figures, giving as a non-limiting
example, an embodiment of a fastening element according to the
invention.
BRIEF DESCRIPTION OF THE FIGURES
[0031] FIG. 1 is a schematic drawing of a sectional view of an
embodiment of a rivet according to the invention fitted in an
orifice passing through two parts to be assembled;
[0032] FIG. 2 illustrates the assembly produced using the
embodiment in FIG. 1.
DESCRIPTION OF PREFERRED EMBODIMENTS
[0033] As illustrated in the drawing in FIG. 1, the rivet R is
fitted in a hole T passing through two plates P1 and P2 to be
assembled. This rivet R has a shank 100 wherein a first end is
equipped with a head 200, the second end being intended to be
deformed to act as a knob 300 (see FIG. 2) forming a bearing
surface to be positioned facing that formed by the head 200, said
shank having a nominal diameter D. As illustrated before
deformation, a portion of the shank 100 of the rivet R projects
outside the hole T. According to the invention, so as to meet the
fatigue and tearing strength criteria, the rivet R is designed such
that the minimum shank length L intended to be deformed to act as
the knob 300, i.e. the minimum shank length projecting outside the
hole T, is equal to 1.25 times the nominal diameter D of the shank
100.
[0034] According to a further particularly advantageous feature of
the invention, the knob 300 obtained after deforming the shank 100
has a maximum thickness e equal to 0.45 times the nominal diameter
D of the shank.
[0035] According to a further feature, the minimum diameter d of
the knob 300, obtained after deformation, is greater than 1.75
times the nominal diameter D.
[0036] Finally, the shank end radius r is equal to the nominal
diameter D of the shank divided by a value ranging between 3 and
3.5.
[0037] It is understood that the fastening element and the method
have been described above and represented for the purposes of
disclosure rather than limitation. Obviously, various adaptations,
modifications and enhancements may be made to the example above,
without leaving the scope of the invention.
* * * * *