U.S. patent application number 12/373128 was filed with the patent office on 2009-11-26 for threaded fastener with retainer and method of making such fastener.
Invention is credited to Charles Earl Abbate, Richard S. Brown, Michael G. Dietz, Chris Fenech.
Application Number | 20090290954 12/373128 |
Document ID | / |
Family ID | 39050972 |
Filed Date | 2009-11-26 |
United States Patent
Application |
20090290954 |
Kind Code |
A1 |
Dietz; Michael G. ; et
al. |
November 26, 2009 |
Threaded Fastener with Retainer and Method of Making Such
Fastener
Abstract
A fastener element (16) has a head section (18), a threaded
shank section (17) with threads (20) at a pitch and a distal end
section (22). A retention device (24) is secured to the distal end
section and is engageable with a fastener receiving member
(14).
Inventors: |
Dietz; Michael G.; (Oxford,
MI) ; Brown; Richard S.; (Brantford, CA) ;
Abbate; Charles Earl; (Clinton Township, MI) ;
Fenech; Chris; (Brownstown, MI) |
Correspondence
Address: |
REISING ETHINGTON P.C.
P O BOX 4390
TROY
MI
48099-4390
US
|
Family ID: |
39050972 |
Appl. No.: |
12/373128 |
Filed: |
July 11, 2007 |
PCT Filed: |
July 11, 2007 |
PCT NO: |
PCT/US2007/015776 |
371 Date: |
January 9, 2009 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
11484821 |
Jul 11, 2006 |
7465137 |
|
|
12373128 |
|
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Current U.S.
Class: |
411/386 ; 470/12;
470/191 |
Current CPC
Class: |
F16B 41/002 20130101;
F16B 25/10 20130101; F16B 35/044 20130101; Y10S 411/999 20130101;
F16B 25/0021 20130101 |
Class at
Publication: |
411/386 ; 470/12;
470/191 |
International
Class: |
F16B 25/00 20060101
F16B025/00; B21H 3/04 20060101 B21H003/04; B21J 13/02 20060101
B21J013/02 |
Claims
1. (canceled)
2. (canceled)
3. (canceled)
4. (canceled)
5. (canceled)
6. (canceled)
7. (canceled)
8. (canceled)
9. (canceled)
10. (canceled)
11. A reusable fastener assembly comprising: a fastener element
having a threaded shank section with threads at a pitch, a head
section, and a distal end section; said distal end section having
an undercut section spaced from an end; a retention device member
engaged to said undercut section with at least one radially
extending flange sized to engage internal threads in a hole of a
fastener receiving member; said at least one flange being tapered
radially outwardly and axially toward said head section and being
flexible in one direction to snap fit into said internal threads
with an axial directed entry force onto said fastener assembly but
resist greater axially directed exiting forces; and said at least
one flange having a pitch corresponding with the pitch of the
threads on said threaded shank section and with said internal
threads of said hole such that said retention device member can be
threaded out of said hole for reuse with said fastener element.
12. A method of manufacturing a fastener assembly comprising the
steps of: roll forming a headed blank to form a threaded fastener
member with threads on a shank portion and a distal end with a
retaining shaped end; placing said threaded fastener member in a
mold; and adheredly molding a retention device on said distal end
with said retaining shaped end.
13. A method as defined in claim 12 further comprising: said roll
forming forms a retaining groove in said distal end; and said
adheredly molding includes molding said retention device in said
retaining groove.
14. A method as defined in claim 12 wherein said threads and said
retainer shaped end are formed simultaneously by said roll
forming.
15. (canceled)
16. A roll die for manufacturing a fastener comprising: a threaded
roll section for rolling threads into a headed blank; and a contour
section at the bottom of the thread roll section with an apex
downstream from an open beginning to roll form a groove in said
headed blank below a formed threaded section.
17. A roll die as defined in claim 16 further comprising: said
contour having its apex near a mid-point of said roll die.
Description
TECHNICAL FIELD
[0001] The field of this invention relates to a threaded fastener
with a retainer at its distal end and a method of manufacturing the
threaded fastener.
BACKGROUND OF THE DISCLOSURE
[0002] Threaded fasteners have long been used to join two or more
components. It has been found advantageous to easily prelocate a
threaded fastener and mate parts prior to torque tightening the
fastener into location by rotating along a thread helix. This is
particularly true with assemblies where the orientation and weight
of the mating parts require that the parts be held in place while a
driving tool is retrieved and placed in location to engage the
fastener for tightening the fastener in place.
[0003] Previous snap in fasteners have been overly complicated and
added unacceptable costs to fasteners when used in high volume
during an assembly line operation.
[0004] What is needed is a low cost expeditiously manufactured
threaded fastener with a retainer that can be pushed into position
with a low entry force and be able to resist a much higher exiting
or pulling force to temporarily hold two mating parts together.
SUMMARY OF THE DISCLOSURE
[0005] In accordance with one aspect of the invention, a fastener
assembly has a fastener member with a head section constructed to
be engageable with a driving tool. A threaded shank section has
threads at a pitch. A retention device member is secured to a
distal end section integrally formed with the fastener member. The
retention device is engageable to a fastener receiving member, for
example a nut, when the distal end section is inserted into a hole
therethrough.
[0006] Preferably the distal end section of the threaded fastener
member has a circumferential groove. The retention device engages
the circumferential groove to be positively engaged onto the distal
end section by being adheredly molded. In one embodiment, the
distal end section is in the form of a dog point.
[0007] The threaded shank section is self-threading for engaging
the hole in the fastener receiving member. The hole is initially
unthreaded. It is desirable that the retention device has at least
one outer extension flange section angled radially outwardly and
axially toward the head section and is sized to engage an inside
wall of the hole in the fastener receiving member to provide
insertion of the fastener assembly in the hole with a low entry
force and to resist higher exiting forces.
[0008] In one embodiment, the retention device is a cap member that
is molded over the distal end section. The cap member has at least
one outer extending flexible flange extending radially outwardly
and axially toward the head section. At least one outer extending
flange has a pitch corresponding to the pitch of threads on the
threaded shank section. The hole in the fastener member can be
initially threaded. The distal end section can be axially inserted
into the hole with a low entry force and resist greater axial
exiting forces and be threaded out of the hole. The flange can snap
fit over the threads in the hole when the fastening member is
axially pushed in.
[0009] According to another aspect of the invention, a fastener
assembly has a fastener element with a self-threading shank
section, an engageable head section and a distal dog point. The
distal dog point has an undercut section spaced from an end. A
retention device member is in the form of an elastomeric cap molded
over the distal dog point with a rim section inwardly extending to
engage and adhere to the undercut section. The cap has at least one
outer flange sized to engage an internal wall of a hole in a
fastener receiving member. At least one outer flange is angled
radially outwardly and axially toward the head section.
[0010] In accordance with another aspect of the invention, a
reusable fastener assembly includes a fastener element having a
threaded shank section with threads at a pitch, a head section, and
a distal end section. The distal end section has an undercut
section spaced from an end. A retention device member is engaged to
the undercut section with at least one radially extending flange
sized to engage internal threads in a hole of a fastener receiving
member. At least one flange is tapered radially outwardly and
axially toward the head section and is flexible in one direction to
snap fit into the internal threads with an axial directed entry
force onto the fastener assembly but resist a higher axial exiting
force. At least one flange has a pitch corresponding with the pitch
of the threads on the threaded shank section and with the internal
threads of the hole such that the retention device member can be
threaded out of the hole for reuse with the fastener element.
[0011] In accordance with another aspect of the invention, a method
of manufacturing a fastener assembly includes the steps of roll
forming a headed blank to form a threaded fastener member with
threads on a shank portion and a distal end with a retaining shaped
end, placing the threaded fastener member in a mold, and adheredly
molding a retention device on the distal end with the retaining
shaped end.
[0012] Preferably, the roll forming forms a retaining groove in the
distal end, and the adheredly molding includes molding the
retention device to extend into the retaining groove.
[0013] In accordance with another aspect of the invention, a method
of manufacturing a threaded fastener includes placing a headed
blank between two roll dies each having a threaded roll section and
a contour section with an apex laterally extending beyond the
threaded roll section and positioned at the bottom end of the
threaded roll section and roll forming the headed blank to
simultaneously form threads and a distal end with a retainer groove
on a shank portion thereof.
[0014] In accordance with another aspect of the invention, a roll
die for manufacturing a fastener has a threaded roll section for
rolling threads into a headed blank, and a contour section at the
bottom of the thread roll section with an apex downstream from an
open beginning to roll form a groove in the headed blank below a
formed threaded section. Preferably, the contour has its apex near
a mid-point of the roll die.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] Reference now is made to the accompanying drawings in
which:
[0016] FIG. 1 is a front perspective view and a segmented view
showing a plurality of fasteners in accordance with one embodiment
of the invention in location temporarily holding an airbag curtain
in location;
[0017] FIG. 2 is side elevation view of one threaded fastener
assembly shown in FIG. 1;
[0018] FIG. 3 is a side segmented and fragmentary view of the
retainer prior to entry to a nut member:
[0019] FIG. 4 is a view similar to FIG. 3 showing the retainer
engaged in a nut member;
[0020] FIG. 5 is a view similar to FIG. 3 showing a modified
embodiment;
[0021] FIG. 6 is a view similar to FIG. 5 showing the modified
retainer engaged in a nut member;
[0022] FIG. 7 is a view similar to FIG. 2 showing a threaded
fastener with a modified retainer;
[0023] FIG. 8 is a fragmentary side and partially segmented view
showing the retainer shown in FIG. 7 engaging a threaded nut;
[0024] FIG. 9 is a perspective view of an alternate embodiment of a
retainer;
[0025] FIG. 10 is a side segmented view illustrating the retainer
cap installed onto a fastener member and engaged with a nut
member.
[0026] FIG. 11 is a perspective view of a pair of threaded roll
dies for use in manufacturing of the fastener shown in FIG. 1;
[0027] FIG. 12 is a sectional view of the two dies in position with
a bolt introduced near the beginning of the cycle;
[0028] FIG. 12a is a top plan view of the dies and bolt shown in
FIG. 12;
[0029] FIG. 13 is an end view of the two dies and bolt shown in
FIG. 12;
[0030] FIG. 14 is a fragmentary perspective view of the fastener
and roll dies shown in FIG. 12;
[0031] FIG. 15 is a schematic view of the overmold station where
the retainer cap member is molded onto the distal end section of
the fastener member; and
[0032] FIG. 16 is a schematic sectional view of the headed blank
and thread roll dies for the fastener shown in FIG. 10.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0033] Referring now to FIG. 1, an airbag anchor and mounting
bracket assembly 10 is secured to sheet metal 12 of a motor vehicle
through a weld nut 14 secured on the back side of the sheet metal
12. A plurality of fastener assemblies 16 can be temporarily
secured to the weld nuts 14 to temporarily hold the anchor and
mounting bracket assembly 10 in place to the sheet metal 12 before
the fasteners assemblies 16 are fully tightened by an appropriate
driving tool (not shown).
[0034] Referring now to FIGS. 2 and 3, a fastener assembly 16
includes a fastener member 17 and a retainer cap member 24. The
fastener member 17 has a head section 18, a threaded shank section
20 that passes through a washer 19. A distal end section 22 is at
the opposite end. The distal end section 22 has the cap member 24
molded thereon. The cap member 24 may be a moldable polymer such as
commercially available PVC. The distal end of a section 22 is in
the form of a dog point 25 with an undercut groove 26 spaced from
the end 28. As shown in FIG. 3, the retainer cap 24 has an inwardly
extending retaining rim 30 that engages the groove 26 to form a
positive lock with the distal end section 22 of the fastener member
to prevent axial removal of the retainer member from the distal end
section 22, i.e., the rim 30 of cap member 24 is overmolded into
the groove 22 to form a positive engagement.
[0035] The retainer cap member 24 also has an outwardly extending
flange 32 that has a taper radially outward and toward the head
section 18. Flange 32 can extend 360 degrees completely about the
cap member outer diameter. The flange 32 also has a diameter sized
larger then the unthreaded hole 34 in the weld nut 14. As shown in
FIG. 4, the fastener assembly can be axially inserted into the nut
hole 34. The yieldably flexible nature of the PVC material and the
taper of the flange 32 allows ease of entry of the retainer cap
into the hole 34. However, the taper and angle of the flange 32
will resist a much higher axially directed exiting force exerted on
fastener member 17. As shown in FIG. 4, the fastener assembly 16
may be inserted until the self tapping threads 36 abut the nut 14
about hole 34.
[0036] Referring to FIGS. 5 and 6, an alternate retainer device 124
is shown on a modified fastener member 117. The fastener member 117
has its dog point distal end section 122 with a groove 126 having a
different profile than that shown in the first embodiment. The
retainer device 124 has an annular ring shape rather than a cap
form such that the dog point distal end section 122 of the fastener
member 117 extends entirely through the retainer device 124. The
retainer device 124 has a similar rim 130 and outer flange 132 as
described for the first embodiment and can be made from a similar
material. The threads 136 are similarly the self-threading type.
The second embodiment provides the low entry force and higher
resistance to exiting forces and functions in the same fashion as
the first embodiment.
[0037] Referring now to FIGS. 7 and 8, a reusable fastener assembly
216 is shown. The retainer cap 224 has a helical outer flange 232
similarly tapered toward the head section 218. A washer 219 is
placed adjacent the head section 218. In addition, the helical
outer flange 232 has a pitch that corresponds with the pitch of
threads 236 on the threaded shank 220. The inner rim 230 is molded
on the dog point distal section 222 of the fastener member 217 in
the same fashion as described for the first embodiment with the rim
230 overmolded into groove 226.
[0038] As shown in FIG. 8, the flange 232 can be axially snap
fitted into the threads 238 of threaded nut 214. However, the shape
and angle of the flange 232 will resist much higher axially
directed exiting forces to prevent the fastener assembly from
axially exiting the nut without rotation. The threads 238 of nut
214 in hole 234 are also pitched at the same angle as the pitch of
the helical flange 232 and threads 236.
[0039] The fastener member 217 with the retainer cap may be rotated
to either fasten the threads into the nut 214 or can be rotated in
an opposite rotational direction to remove both the fastener member
217 and the retainer cap 224 from the nut 214 such that the
fastener assembly 216 may be reused.
[0040] The reusable fastener element shown in FIGS. 7 and 8 are
desirable for field use such as attaching armor plating to humvees
and the other military vehicles that may need extra armor. The
fastener easily allows one person to lift the armor plate and push
in the fastener element to temporarily hold the armor plate onto
the vehicle while the person retrieves a fastener tool to then
tighten the fastener elements in place. The fastener elements can
be threadably removed when it is desired to remove the armor from
the vehicle and retains its structural integrity and shape to be
reused.
[0041] All of the above embodiments provide temporary retention
with the nut without the need of the fastener assembly protruding
beyond the nut. This aspect is advantageous when there is little or
no space or clearance behind the nut. However it is foreseen that
many applications may provide for a clearance or extra space behind
the nut. In these applications a retainer device 324 may have its
outer flange 332 as shown in FIGS. 9 and 10 inserted totally
through the nut to engage the backside of the nut to prevent the
fastener from disengaging. It still has its inner rim section 330
engaging the groove 326 to provide a positive interconnection
between the retainer cap and a fastener member. In this embodiment,
it is noted that the profile of the undercut groove 326 has
transverse shoulder 335 with the dog point distal section 322 and
this provides a stronger resistance against exiting pulling forces
exerted on the fastener member. The retainer device 324 has spaces
337 between the flange 332 and a pair of axially extending slots
340 extending from distal end section 343 through tapering section
342 and up to rim section 330 to provide extra flexibility to the
retainer device 324 as it passes through hole 334.
[0042] For all the above described embodiments, a fastener can be
temporarily located in either a threaded or unthreaded nut hole
holding two members temporarily in place. While these fastener
assemblies are particularly suitable to be dimensioned for
resisting up to 5 lb. of exiting force without disengaging the nut
for retaining the airbag anchor in place, the fastener assemblies
may be sized up or down for other applications, including
applications with exiting forces exceeding 5 lbs. The fastener can
be quickly pushed into place while an operator may then retrieve an
appropriate driving tool to then rotate each fastener member along
its thread helix to its final tightened condition with the nut. The
use of these fastener assemblies provides for a so called third
hand for the operator and can speed up an assembly line type
operation.
[0043] For lighter duty applications, the overmold feature of the
rim 30 into a groove 26 may be eliminated and the fastener member
may be retained solely by frictional engagement between the cap
member molded onto the fastener member.
[0044] Referring now to FIGS. 11-14, the fastener member 17 is
expeditiously manufactured by using two thread roll dies 44. One
die 44 is stationary and the other is movable with a headed bolt
blank 48 positioned therebetween. Each die 44 has thread rolls 50
to form the threads 36 on the shank portion 20 in a conventional
fashion. Each roll die 44 also has a rising contour 52 which rises
from the open ends 54 toward the apex 56 near the middle axis 57 of
the respective die 44. The contour 52 forms the distal end section
22 with the groove 26. The headed bolt blank 48 rolls with the
relative movement of the dies 44 in much the same fashion as clay
is rolled between a person's sliding hands to form an elongated
roll of clay. The fastener member 17 is fully formed with threads
and its contoured distal end once the blank approached the middle
section of both dies 44. The progression of the contour 52 to form
the groove 26 is more clearly shown in FIGS. 12, 12a and 13. In
FIG. 12, the sectional view is shown near the beginning of the roll
operation before the distal end 22 is fully formed. The contour is
not yet fully intruded into the blank. FIG. 12a clearly shows the
bolt 17 interposed between the two dies 49. As shown in FIG. 13,
the contour is better shown in phantom as the opposing dies 44 are
rolling the blank where each die 44 pinches and forces metal
movement of the blank to form the distal end 22 and groove 26
simultaneously as the threads 36 are also formed. As shown in FIG.
14, the finished fastener member 17 is shown near the midpoint of
each die 44.
[0045] Once the fastener is expeditiously formed using the roll
dies, the fastener member 17 is placed in a mold 60 as shown in
FIG. 15. Elastomeric material is injected into a cavity 62 formed
within the mold and against the fastener member 17. The cavity 62
has the shape corresponding to the shape of the retainer cap member
24. After the newly formed retainer cap member 24 is sufficiently
cooled and set, the mold 60 can be opened to obtain the finished
fastener assembly 16.
[0046] Referring now to FIG. 16, a schematic of the roll dies 344
and a headed blank 348 with a shank portion 320 and distal portion
322 is shown which is used to make the fastener element 317 as
shown in FIG. 10. The concept and operation of the rolls 344 is the
same as above described with thread section 350 but the rolls have
a different contour 352 to provide a different shaped distal end
section 322 for increased exiting pull forces as above
described.
[0047] Other variations and modifications are possible without
departing from the scope and spirit of the present invention as
defined by the appended claims.
* * * * *