U.S. patent application number 10/741451 was filed with the patent office on 2004-07-29 for fastener and its setting method.
This patent application is currently assigned to Newfrey LLC. Invention is credited to Adachi, Ryoichi, Hidaka, Tomoaki, Kashimura, Shuji, Kobayashi, Ichiro, Minami, Mitsuhiro.
Application Number | 20040143943 10/741451 |
Document ID | / |
Family ID | 32501169 |
Filed Date | 2004-07-29 |
United States Patent
Application |
20040143943 |
Kind Code |
A1 |
Minami, Mitsuhiro ; et
al. |
July 29, 2004 |
Fastener and its setting method
Abstract
A fastener comprises a flange having an insertion hole, a
plurality of circumferentially spaced clamping legs extending from
the flange, and a nut connected integrally to ends of the clamping
legs. The nut and the clamping legs are inserted into a mounting
hole of a workpiece. Then the nut is pulled toward the flange to
cause buckling of the clamping legs. The fastener is set to the
workpiece by clamping the workpiece between the buckled clamping
legs and the flange. Each of the clamping legs has a buckling
portion, a nut-side leg portion and a flange-side leg portion. The
buckling portion is thinner than the nut-side and flange-side leg
portions. The nut-side leg portion has a higher strength than the
flange-side leg portion. A region of the nut-side leg portion
adjacent to the nut has a lower strength than that of the remaining
region thereof.
Inventors: |
Minami, Mitsuhiro;
(Toyohashi-shi, JP) ; Kashimura, Shuji;
(Aichi-ken, JP) ; Adachi, Ryoichi; (Niiza-shi,
JP) ; Kobayashi, Ichiro; (Niiza-shi, JP) ;
Hidaka, Tomoaki; (Niiza-shi, JP) |
Correspondence
Address: |
MILES & STOCKBRIDGE PC
1751 PINNACLE DRIVE
SUITE 500
MCLEAN
VA
22102-3833
US
|
Assignee: |
Newfrey LLC
|
Family ID: |
32501169 |
Appl. No.: |
10/741451 |
Filed: |
December 22, 2003 |
Current U.S.
Class: |
24/453 |
Current CPC
Class: |
Y10T 24/42 20150115;
F16B 37/067 20130101 |
Class at
Publication: |
024/453 |
International
Class: |
A41F 001/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 6, 2003 |
JP |
2003-000282 |
Claims
What is claimed is:
1. A fastener comprising: a flange having an insertion hole for
receiving a bolt therethrough, and a portion outside the insertion
hole to be brought into juxtaposition with a workpiece; a plurality
of clamping legs extending from a region of the flange outside the
insertion hole and being circumferentially spaced apart from each
other; and a nut connected integrally to ends of the clamping legs,
wherein the nut and the clamping legs are inserted into a mounting
hole of the workpiece, and then the nut is pulled toward the flange
to cause buckling of the clamping legs in such a manner that a
buckling portion in each of the clamping legs at an intermediate
region thereof is expanded radially outward to allow the fastener
to be set to the workpiece by clamping the workpiece between the
buckled clamping legs and the flange, wherein the buckling portion
in each of the clamping legs is thinner than the remaining portion
of the clamping leg to allow a buckling beginning point to be
located thereat, the remaining portion including a nut-side leg
portion extending from the buckling portion to the nut, and a
flange-side leg portion extending from the buckling portion to the
flange; and wherein the nut-side leg portion is relatively thick so
as to have a higher strength than that of the flange-side leg
portion, and a region of the nut-side leg portion adjacent to the
nut is relatively thin so as to have a lower strength than the
remaining region thereof.
2. The fastener as defined in Claim 1, wherein the flange has a
shape with at least two parallel linear sides in plan view, the
shape being selected from a group including a quadrangle, a
hexagon, and a pseudo-ellipse formed by cutting a circle shape with
two parallel straight lines.
3. A fastener comprising: a flange having an insertion hole for
receiving a bolt therethrough, and a portion outside the insertion
hole and adapted to be brought into juxtaposition with a workpiece;
a plurality of clamping legs extending from a region of the flange
outside the insertion hole and being circumferentially spaced apart
from each other; and a nut connected integrally to ends of the
clamping legs, wherein the nut and the clamping legs are inserted
into a mounting hole of the workpiece, and then the nut is pulled
toward the flange to cause buckling of the clamping legs in such a
manner that a buckling portion in each of the clamping legs at an
intermediate region thereof is expanded radially outward to allow
the fastener to be set to the workpiece by clamping the workpiece
between the buckled clamping legs and the flange, and wherein the
flange has a shape with at least two parallel linear sides in plan
view, the shape being selected from a group including a quadrangle,
a hexagon, and a pseudo-ellipse formed by cutting a circle shape
with two parallel straight lines.
4. A method for setting the fastener as defined in Claim 2 to a
workpiece, comprising the steps of: inserting a bolt through the
insertion hole of the flange of the fastener to threadedly engage
the bolt with the nut, and inserting the nut and the clamping legs
of the fastener with the bolt into a mounting hole of the workpiece
to bring the flange into juxtaposition with the workpiece; engaging
either a general-purpose tool or a portion of the workpiece with
the at least two linear sides of the flange to prevent the fastener
from being rotated upon the rotation of the bolt; and rotating the
bolt relative to the fastener to further screw the bolt into the
nut so as to pull the nut toward the flange to cause buckling of
the clamping legs in such a manner that the buckling portion in
each of the clamping legs is expanded radially outward to allow the
fastener to be set to the workpiece by clamping the workpiece
between the buckled clamping legs and the flange.
5. A method for setting the fastener as defined in Claim 3 to a
workpiece, comprising the steps of: inserting a bolt through the
insertion hole of the flange of the fastener to threadedly engage
the bolt with the nut, and inserting the nut and the clamping legs
of the fastener with the bolt into a mounting hole of the workpiece
to bring the flange into juxtaposition with the workpiece; engaging
either a general-purpose tool or a portion of the workpiece with
the at least two linear sides of the flange to prevent the fastener
from being rotated upon the rotation of the bolt; and rotating the
bolt relative to the fastener to further screw the bolt into the
nut so as to pull the nut toward the flange to cause buckling of
the clamping legs in such a manner that the buckling portion in
each of the clamping legs is expanded radially outward to allow the
fastener to be set to the workpiece by clamping the workpiece
between the buckled clamping legs and the flange.
6. A fastener as defined in Claim 3, wherein the buckling portion
in each of the clamping legs is thinner than the remaining portion
of the clamping leg to allow a buckling beginning point to be
located thereat, the remaining portion including a nut-side leg
portion extending from the buckling portion to the nut, and a
flange-side leg portion extending from the buckling portion to the
flange.
7. A fastener as defined in Claim 6, wherein the nut-side leg
portion is relatively thick so as to have a higher strength than
the flange-side leg portion, and a region of the nut-side leg
portion adjacent to the nut is relatively thin so as to have a
lower strength than the remaining region thereof.
8. A fastener as defined in Claim 7, wherein the flange-side leg
portion tapers from a wider width at the flange to a narrower width
at the buckling portion.
9. A fastener as defined in Claim 8, wherein the flange-side leg
portion is longer than the nut-side leg portion.
10. A fastener as defined in Claim 6, wherein the nut-side leg
portion has reduced thickness portions at opposite ends thereof
adjacent to the nut and to the flange-side leg portion,
respectively.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application claims the benefit of Japanese Patent
Application No. 2003-000282 filed Jan. 6, 2003, incorporated herein
by reference.
BACKGROUND OF THE INVENTION
[0002] The present invention relates to an improved blind nut type
fastener capable of being set to a workpiece, such as a panel, on
one side of the workpiece, more specifically, to a blind nut type
fastener comprising a flange formed with a bolt-insertion hole, a
plurality of clamping legs extending from a region of the flange
outside the insertion hole, and a nut connected commonly and
integrally to all of the ends of the clamping legs.
[0003] There has been known a blind nut type fastener capable of
being set to a workpiece, such as a panel, through a one-side
operation, that is, on one side of the workpiece. For example, a
blind nut type fastener commercially available under the trademark
"JACK Nuts" comprises a flange having an insertion hole for
receiving a bolt therethrough and a contact portion outside the
insertion hole and adapted to be brought into contact with a
workpiece, a plurality of clamping legs extending from a region of
the flange outside the insertion hole and being circumferentially
spaced apart from each other, and a nut connected commonly and
integrally to all of the ends of the clamping legs. This fastener
is attached to a screw mandrel of a dedicated setting tool, and the
nut and the clamping legs are inserted into a mounting hole of a
workpiece. The setting tool is activated to pull the nut toward the
flange, and then buckling is caused in the clamping legs in such a
manner that a buckling portion in each of the clamping legs at an
intermediate region thereof is expanded radially outward to allow
the fastener to be set to the workpiece by clamping the workpiece
between the buckled clamping legs and the flange.
[0004] As another blind nut type fastener, Japanese Utility Model
Laid-Open No. 60-29909 (Publication 1) discloses a single-piece
anchor rivet press-formed from a single metal sheet. Japanese
Utility Model Laid-Open No. 01-82310 (Japanese Utility Model
Publication No. 02-39052: Publication 2) discloses a two-piece
fastener comprising a nut-like rivet member and a bolt member
threadedly inserted into the rivet member. Japanese Patent
Laid-Open No. 10-148207 (Publication 3) also discloses a two-piece
fastener comprising a tubular member having a flange-shaped head
with a slot and internal thread, and an externally threaded shank
member to be threadedly inserted into the tubular member. Further,
Japanese Patent Laid-Open No. 2000-176853 (Publication 4) proposes
a jig adapted to be attached to the front end of a general-purpose
impact-driver tool, to set a two-piece fastener comprising a rivet
body having a hexagonal head and a tubular body formed with a slit
and internal thread, and an expanding screw to be threadedly
inserted into the rivet body. This jig is intended to allow the
fastener to be set without using any expensive dedicated setting
tool.
[0005] In the aforementioned conventional blind nut type fastener,
which comprises a flange having a bolt-insertion hole and a contact
portion outside the insertion hole and adapted to be brought into
contact with a workpiece, a plurality of clamping legs extending
from the flange while being circumferentially spaced apart from
each other, and a nut connected commonly and integrally to all of
the ends of the clamping legs, the buckling portion in each of the
clamping legs is apt to be buckled in a way that pushes the
workpiece upward instead of buckling such that it is expanded
outwardly of the fastener. Thus, if the workpiece is a thin panel,
the workpiece will be undesirably warpage-deformed by the pushing
force of the buckled portion. Neither any awareness of this problem
nor any solution therefor is disclosed in the above-mentioned
Publications 1 to 4. In addition, the aforementioned conventional
blind nut type fastener is constructed on the assumption of using a
dedicated setting tool. Furthermore, if the fastener is rotated
together with the bolt, during a setting operation, it is likely to
fail to stop its lost motion.
[0006] While the fastener disclosed in Publication 1 has a flange
formed with pawls to bite into a workpiece to prevent the rotation
of the fastener, the pawls are not effective for a metal plate as
the workpiece, and the sharp edge of each pawl is undesirable in
terms of operator's safety. In the fasteners disclosed in
Publications 2 to 4, a flange of the nut member is formed in a
hexagonal shape to prevent the fastener from being rotated together
with the bolt member. The fasteners disclosed in Publications 2 to
4 are formed in a configuration to be set without using any
dedicated setting tool. However, each of the fasteners disclosed in
Publications 2 to 4 is a two-piece fastener essentially including a
nut member and a bolt member, but not a fastener including only a
nut member.
BRIEF DESCRIPTION OF THE INVENTION
[0007] It is therefor an object of the present invention to provide
a single-piece fastener capable of eliminating the risk of causing
warpage-deformation of a workpiece even if the workpiece is a thin
panel.
[0008] The present invention provides, in one embodiment, a unitary
fastener comprising a flange having an insertion hole for receiving
a bolt therethrough and a contact portion outside the insertion
hole and adapted to be brought into juxtaposition with a workpiece,
a plurality of clamping legs extending from a region of the flange
outside the insertion hole and being circumferentially spaced apart
from each other, and a nut connected integrally to ends of the
clamping legs. The nut and the clamping legs are inserted into a
mounting hole of the workpiece, and then the nut is pulled toward
the flange to cause buckling of the clamping legs in such a manner
that a buckling portion in each of the clamping legs at an
intermediate region thereof is expanded radially outward to allow
the fastener to be set to the workpiece by clamping the workpiece
between the buckled clamping legs and the flange. In a particular
form of this fastener, the buckling portion in each of the clamping
legs is thinner than the remaining portion of the clamping leg to
allow a buckling beginning point to be located thereat. The
remaining portion comprises a nut-side leg portion extending from
the buckling portion to the nut, and a flange-side leg portion
extending from the buckling portion to the flange. The nut-side leg
portion is relatively thick, so as to have a higher strength than
that of the flange-side leg portion, and a region of the nut-side
leg portion adjacent to the nut is relatively thin, so as to have a
lower strength than that of the remaining region thereof.
[0009] The above fastener is formed as a single-piece component,
and in a particular form the buckling portion in each of the
clamping legs of this fastener is thinner than the remaining
portion of the clamping leg, the nut-side leg portion has a higher
strength than the flange-side leg portion, and the region of the
nut-side leg portion adjacent to the nut has a lower strength than
that of the remaining region thereof. Thus, the buckling portion in
each of the clamping legs is expanded outwardly, or in parallel
with the surface of the workpiece during the setting operation, and
the buckled portion is pulled toward the flange in the axial
direction of the fastener so that its expanded posture is
maintained upon completion of the setting operation. Therefore,
little if any pushing force is applied to the workpiece, preventing
warpage-deformation of the workpiece even if the workpiece is a
thin panel. In addition, since the buckling portion in each of the
clamping legs has a lower strength than the remaining portion of
the clamping leg, a pulling torque during the setting operation can
be maintained at a lower level to reduce an operator's load in
either a dedicated tool or a general-purpose tool.
[0010] In the above fastener, the flange may have a shape with at
least two parallel linear sides in plan view, e.g., a shape
selected from a group including a quadrangle, a hexagon, and a
pseudo-ellipse formed by cutting a circle shape with two parallel
straight lines. This flange allows a general-purpose tool such as a
screw wrench or spanner to be engaged therewith, so as to prevent
rotation of the fastener. Thus, the fastener can be set to a
workpiece using a general-purpose hand-operated tool, such as a
spanner or screwdriver.
[0011] According to the present invention, another unitary fastener
is provided, which comprises a flange having an insertion hole for
receiving a bolt therethrough and a contact portion outside the
insertion hole and adapted to be brought into juxtaposition with a
workpiece, a plurality of clamping legs extending from a region of
the flange outside the insertion hole and being circumferentially
spaced apart from each other, and a nut connected integrally to
ends of the clamping legs, wherein the nut and the clamping legs
are inserted into a mounting hole of the workpiece, and then the
nut is pulled toward the flange to cause buckling of the clamping
legs in such a manner that a buckling portion in each of the
clamping legs at an intermediate region thereof is expanded
radially outward to allow the fastener to be set to the workpiece
by clamping the workpiece between the buckled clamping legs and the
flange. In this fastener, the flange may be have a shape with at
least two parallel linear sides in plan view, e.g., a shape
selected from a group including a quadrangle, a hexagon, and a
pseudo-ellipse formed by cutting a circle shape with two parallel
straight lines. This fastener can also be set to a workpiece using
a general-purpose hand-operated tool such as a spanner or
screwdriver.
[0012] A method for setting the above-mentioned fasteners to the
workpiece using a general-purpose hand-operated tool is provided.
That method comprises the steps of: inserting a bolt through the
insertion hole of the flange of the fastener to threadedly engage
the bolt with the nut, and inserting the nut and the clamping legs
of the fastener with the bolt into a mounting hole of the workpiece
to bring the flange into juxtaposition with the workpiece; engaging
the general-purpose tool, such as a spanner, with the at least two
linear sides of the flange to prevent the fastener from being
rotated upon the rotation of the bolt; and rotating the bolt
relative to the fastener to further screw the bolt into the nut so
as to pull the nut toward the flange to cause buckling of the
clamping legs in such a manner that the buckling portion in each of
the clamping legs is expanded radially outward to allow the
fastener to be set to the workpiece by clamping the workpiece
between the buckled clamping legs and the flange. This method can
eliminate the need for using a dedicated setting tool.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] The invention will be further described in conjunction with
the accompanying drawings, which illustrate preferred (best mode)
embodiments, and wherein:
[0014] FIG. 1 is a front view of a fastener according to one
embodiment of the present invention;
[0015] FIGS. 2A-2C are top plan views of various flanges useful in
the present invention, wherein FIG. 2A shows a flange having a
quadrangular shape in top plan view, FIG. 2B shows a flange having
a hexagonal shape in top plan view, and FIG. 2C shows a flange
having a pseudo-elliptical shape in top plan view formed by cutting
a circle shape with two parallel straight lines;
[0016] FIG. 3 is a front view of a fastener which may have a flange
selected from the flanges shown in FIGS. 2A-2C;
[0017] FIGS. 4A-4C are illustrative views of setting stages of a
blind nut type fastener similar to that shown in FIG. 3, wherein
FIG. 4A shows the state after the fastener is inserted into a
workpiece, FIG. 4B shows the state in the course of the setting
operation, and FIG. 4C shows the state after the completion of the
setting operation;
[0018] FIGS. 5A-5C are illustrative views of setting stages of a
fastener according to the present invention, wherein FIG. 5A shows
the state after the fastener is inserted into a workpiece,
[0019] FIG. 5B shows the state in the course of the setting
operation, and FIG. 5C shows the state after the completion of the
setting operation;
[0020] FIGS. 6A-6C are illustrative views of setting operations of
a fastener according to the present invention to a workpiece using
a dedicated tool, wherein FIG. 6A shows the state after the
fastener attached to the dedicated tool is inserted into the
workpiece, FIG. 6B shows the state just after the completion of the
setting operation, and FIG. 6C shows the state after an additional
attachment member is attached to the workpiece using the fastener
set to the workpiece;
[0021] FIG. 7 is a perspective view of a first step of a method for
attaching a fastener according to the present invention to a
workpiece using a general-purpose tool, such as a spanner,
particularly an operation for engaging a bolt with the fastener,
inserting the fastener into the workpiece, and preventing the
rotation of the fastener using a spanner; and
[0022] FIGS. 8A-8C are illustrative views of subsequent steps of
the method for setting the fastener to the workpiece in FIG. 7,
wherein FIG. 8A shows the state when the bolt is rotated relative
to the fastener immovably retained by the spanner, by using a
screwdriver, FIG. 8B shows the state after the setting operation is
completed, and the bolt is detached, and FIG. 8C shows the state
after an additional attachment member is attached to the workpiece
using the fastener set to the workpiece.
DETAILED DESCRIPTION OF THE INVENTION
[0023] With reference to the drawings, the present invention will
now be described. FIG. 1 shows a unitary fastener 1 according to
one embodiment. The fastener 1 can be made of metal, such as steel
or aluminum, and integrally formed as a single-piece component
comprising a flange 2, a plurality of clamping legs 3 and a nut 5.
The flange 2 has an insertion hole 6 formed in the central region
thereof to receive a bolt therethrough, and a portion 7 outside the
insertion hole with a smooth surface adapted to be brought into
juxtaposition or into contact with a workpiece such as a panel.
Each of the clamping legs is formed as an elongated plate-shaped
member extending from a region of the flange 2 outside the
insertion hole 6. The plurality of clamping legs 3 are arranged
such that they are circumferentially spaced apart from each other.
Although the number of legs provided is four in the illustrated
embodiment, any other suitable number of legs may be selected. All
of the ends of the clamping legs 3 are connected with a nut 5
commonly and integrally. The nut 5 has a tubular internal thread
portion 9 therein. The internal thread portion 9 is formed with an
internal thread adapted to be threadedly engaged with a bolt
inserted through the insertion hole 6.
[0024] Each of the clamping legs 3 has a buckling portion 10 which
is located at an intermediate region thereof. When the nut 5 is
pulled toward the flange, buckling is caused in the buckling
portion 10 such that it is expanded radially outward. A workpiece
is clamped between the buckled clamping legs 3 and the flange 2 to
allow the fastener 1 to be set to the workpiece. The buckling
portion 10 is thinner than, i.e., narrower than, the remaining
portion of the clamping leg to allow a buckling beginning point to
be located thereat. A nut-side leg portion 11 extends from the
buckling portion 10 to the nut 5, and the nut-side leg portion 11
is relatively thick to have a higher strength than a flange-side
leg portion 13 which extends from the buckling portion 10 to the
flange 2. In the illustrated embodiment, the nut-side leg portion
11 has a width greater than that of the flange-side leg portion 13
to obtain a higher strength than the flange-side leg portion
13.
[0025] As illustrated, the flange-side leg portion 13 is tapered so
as to have a relatively wide width at the flange 2 and to have a
narrower width approaching the buckling portion 10. This
configuration is desirable to create buckling of the clamping legs
3 smoothly and to provide increased strength of the respective
anchor ends of the buckled clamping legs 3. In each of the clamping
legs 3, the flange-side leg portion 13 is also formed slightly
longer than the nut-side leg portion 11. This configuration is
desirable to maintain the posture of the buckled clamping legs 3
when they have been finally brought in surface contact with the
workpiece. Further, in each of the clamping legs 3, a region of the
nut-side leg portion 11 adjacent to the nut 5 is relatively thin to
have a lower strength than the remaining region thereof. In the
illustrated embodiment, the region of the nut-side leg portion 11
adjacent to the nut 5 is formed with a pair of notches 14 for
providing a narrowed width in the nut-side leg portion 11, so that
the region with the notches 14 is thinned to have a lower strength
than the remaining region of the nut-side leg portion. As shown in
FIG. 1, the nut-side leg portion 11 has reduced thickness portions
at its opposite ends adjacent to the nut 5 and the flange-side leg
portion 13, respectively.
[0026] FIGS. 2A to 2B show various shapes of the flange 2. In FIG.
2A, the flange 2A has a quadrangular shape in top plan view. In
FIG. 2B, the flange 2B has a hexagonal shape in top plan view. In
FIG. 2C, the flange 2C has a pseudo-ellipse shape in top plan view,
formed by cutting a circle with two parallel straight lines. As
shown in these examples, the flange may be formed in any suitable
shape having at least two parallel linear sides. This flange allows
a general-purpose tool such as a spanner to be engaged therewith to
prevent the rotation of the fastener 1. Thus, during the operation
of rotating a bolt inserted into the fastener, the fastener 1 can
be prevented from being rotated upon the rotation of the bolt, and
the fastener 1 can be set to the workpiece using a general-purpose
hand-operated tool, such as a spanner or screwdriver, as well as a
dedicated setting tool. The shapes of the flanges 2A to 2C may be
applied to a fastener 15 as shown in FIG. 3, which does not
includes notches 14 of the fastener 1 of FIG. 1.
[0027] FIGS. 4A to 4C show the state when a blind nut type fastener
21 similar to that shown in FIG. 3 is set to a workpiece 22. The
fastener 21 comprises a flange 17, a plurality of clamping legs 18
extending from the flange 17 while being circumferentially spaced
apart from each other, and a nut 19 connected commonly and
integrally to all of the ends of the clamping legs. As shown in
FIG. 4A, the nut 19 and the clamping legs 18 of the fastener 21 are
first inserted into a mounting hole of the workpiece 22 to bring
the flange 17 into surface contact with the workpiece 22. Then, as
shown in FIG. 4B, the nut 19 is pulled toward the flange 17 in the
direction of the arrow 23 using a setting tool. Through this
operation, the clamping legs 18 are deformed such that a buckling
portion in each of the clamping legs is expanded radially outward.
During this deformation, the clamping legs 18 are apt to be buckled
in a way that pushes the workpiece 22 upward instead of buckling
such that each of the buckling portions is expanded in parallel
with the workpiece 22. Thus, if the workpiece 22 is a thin panel,
an undesirable warpage-deformation of the workpiece 22 due to the
upward-pushing force of the buckled clamping legs 18 may occur, as
shown in FIG. 4C.
[0028] FIGS. 5A to 4C show the state when the fastener 1 of the
present invention is set to the workpiece 22. As shown in FIG. 5A,
the nut 5 and the clamping legs 3 of the fastener 1 are first
inserted into the mounting hole of the workpiece 22 to bring a
smooth surface of the contact portion of the flange 2 into
juxtaposition or surface contact with the workpiece 22. Then, as
shown in FIG. 5B, the nut 5 is strongly pulled toward the flange 2
in the direction of the arrow 23. Through this operation, the
clamping legs 3 are deformed such that the buckling portions 10 are
expanded radially outward. During this deformation, the clamping
legs 3 are buckled such that each of the buckling portions 10 is
expanded outwardly or in parallel with the workpiece 22 (in the
direction of the arrows 25). This buckling is obtained because the
region of the nut-side leg portion 11 adjacent to the nut 5 in each
of the clamping legs 3 is formed with the pair of notches 14 so as
to have a lower strength than the remaining region thereof. As
indicated by the dashed-line arrows 26, the nut-side leg portion 11
in each of the clamping legs 3 reduces the upward-pushing force in
proportion to the level of decrease in the strength of the region
of the nut-side leg portion 11 adjacent to the nut 5. When the
setting operation is continued, the clamping legs 3 are
continuously buckled outwardly (in a direction parallel to the
surface of the workpiece 22).
[0029] The setting operation reaches the final stage without
applying any significant upward-pressing force to the workpiece 22.
As shown in FIG. 5C, upon completion of the setting operation, the
buckled clamping legs 3 are simply pulled toward the flange 2 along
the axis of the fastener while maintaining their outwardly expanded
posture, and no upward stress is applied the to the workpiece.
Therefore, even if the workpiece 22 is a thin panel 22,
warpage-deformation can be prevented. The buckled clamping legs 3
are located along the surface of the workpiece 22. Thus, the
workpiece 22 is firmly clamped between the buckled clamping legs 3
and the flange 2 without any deterioration in the clamping force of
the fastener 1 to the workpiece 22. Furthermore, since the region
of the nut-side leg portion 11 adjacent to the nut 5 in each of the
clamping legs 3 is formed with the notches 14 so as to have a lower
strength than the remaining region thereof, the expansive buckling
can be achieved by a lower force than that required in clamping
legs devoid of notches, allowing the pulling force during the
setting operation to be maintained at a lower level, so as to
reduce an operator's load in either a dedicated tool or a
general-purpose tool.
[0030] FIGS. 6A to 6C show the state in which the fastener 1 is set
to the workpiece 22 using a dedicated setting tool 27. In these
drawings, the fastener 1 is depicted larger than the setting tool
27 in an exaggerated form only for easy understanding. A screw
mandrel 29 capable of being threadedly inserted into the nut 5 of
the fastener 1 is provided at the front end of the setting tool 27,
and the fastener 1 is threadedly engaged with the screw mandrel 29.
As shown in FIG. 6A, an operator who holds the setting tool 27 with
the fastener attached thereto inserts the nut 5 and the clamping
legs 3 of the fastener 1 into the mounting hole of the workpiece 22
to bring the contact surface portion of the flange 2 into surface
contact with the workpiece 22. Then, as shown in FIG. 6B, the nut 5
is strongly pulled toward the flange 2 in the direction of the
arrow 23 to deform the clamping legs 3 in such a manner that the
buckling portions 10 are expanded radially outward. The workpiece
22 is firmly clamped between the buckled clamping legs 3 and the
flange 2 to allow the fastener 1 to be set to the workpiece 22.
[0031] Since the region of the nut-side leg portion 11 formed with
the notches 14 in each of the clamping legs 3 has a lower strength,
the pulling torque during the above setting operation can be
maintained at a lower level than that required with clamping legs
devoid of notches so as to reduce a load of the operator who
handles the setting tool 27. After the completion of the setting,
the screw mandrel 29 is reversely rotated and pulled out of the
fastener 1 to detach the setting tool 27 from the fastener 1. Then,
for example, a mounting hole of an additional attachment member 30,
such as a bracket, is positioned so as to be aligned with the
bolt-insertion hole 6 of the flange 6. A bolt 31 is then inserted
through the mounting hole and the insertion hole, and threadedly
engaged with the nut 5 to connect the attachment member 30 to the
workpiece 22.
[0032] FIG. 7 and FIGS. 8A to 8C show a method of setting the
fastener 1 having a flange of a shape selected from the shapes in
FIGS. 2A-2C, using a general-purpose tool, such as a spanner or
screwdriver, instead of a dedicated setting tool. Although the
following description assumes a fastener having a quadrangular
flange illustrated in FIG. 2A, it is understood that a flange
illustrated in FIG. 2B or 2C or any other flange having two or more
parallel linear sides may be used. FIG. 7 shows an explanatory
perspective view of an initial step of the setting method. FIGS. 8A
to 8C show subsequent steps.
[0033] As shown in FIG. 7, a bolt 31 is inserted into the fastener
1 through the insertion hole of the flange 2, and threadedly
engaged with the nut 5 to attach the bolt 31 to the fastener 1. The
nut 5 and the clamping legs 3 of the fastener 1 with the bolt are
inserted into the mounting hole of the workpiece 22 to bring the
flange 2 of the fastener 1 into surface contact with the workpiece
22. Then, a general-purpose tool, such as a spanner 22, is engaged
with the two linear sides of the flange 2 of the fastener 1 to
prevent the fastener 1 from being rotated upon the rotation of the
bolt 3. Instead of the engagement with the general-purpose tool, a
portion or portions of the workpiece may be engaged with the two
linear sides of the flange 2 of the fastener 1 to prevent the
rotation of the fastener 1.
[0034] As shown in FIG. 8A, by using a general-purpose tool such as
a screwdriver 34, the bolt 31 is rotated relative to the fastener 1
immovably retained by the spanner 33 to further screw the bolt 31
into the nut 5 strongly. Through this operation, the nut 5 of the
fastener 1 is pulled toward the flange 2 to cause buckling of the
clamping legs 3 in such a manner that the buckling portion 10 in
each of the clamping legs 3 is expanded radially outward. The
workpiece 22 is clamped between the buckled clamping legs 3 and the
flange 2 to allow the fastener 1 to be set to the workpiece 22 (see
FIG. 8B). Even if the fastener is apt to be rotated together with
the bolt during the setting operation, such rotation can be stopped
by the spanner 33.
[0035] Since the region of the nut-side leg portion 11 formed with
the notches 14 in each of the clamping legs 3 has a lower strength,
the pulling torque during the above setting operation can be
maintained at a lower level than that required with clamping legs
devoid of notches. Where a fastener having clamping legs without
any notches is set by a screwdriver which is manually driven by an
operator, a higher pulling torque is necessary to set the fastener,
leading to difficulty in setting the fastener. On the contrary,
where the region of the nut-side leg portions 11 is formed with the
notches 14 in each of the clamping legs 3 for a lower strength, the
pulling torque can be reduced to allow the fastener 1 to be
manually set using a general-purpose screwdriver without any
difficulties.
[0036] After the completion of the setting, the bolt 31 can be
detached as shown in FIG. 8B. Then, for example, a mounting hole of
an additional attachment member 30, such as a bracket, is
positioned so as to be aligned with the bolt-insertion hole 6 of
the flange 2. The bolt 31 can be then inserted through the mounting
hole and the insertion hole, and threadedly engaged with the nut 5
to connect the attachment member 30 to the workpiece 22.
[0037] A fastener according to the present invention is formed as a
single-piece component, and the buckling portion in each of the
clamping legs is expanded outwardly, or in parallel with the
surface of a workpiece, during the setting operation, and the
buckling portion is pulled toward the flange along the axis of the
fastener so that its expanded posture is maintained upon completion
of the setting operation. Thus, no significant pushing force is
applied to the workpiece, preventing warpage-deformation of the
workpiece even if the workpiece is a thin panel. The flange may be
formed in a shape having at least two parallel linear sides in top
plan view to allow the fastener to be set to a workpiece using a
general-purpose tool such as a screw wrench or spanner. In
addition, since the buckling portion in each of the clamping legs
has a lower strength than the remaining portion of the clamping
leg, a pulling torque during the setting operation can be
maintained at a lower level to reduce an operator's load in either
a dedicated tool or a general-purpose tool.
[0038] While preferred embodiments of the invention have been shown
and described, it will be apparent that modifications can be made
without departing from the principles and spirit of the invention,
the scope of which is defined in the appended claims.
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