U.S. patent application number 10/395185 was filed with the patent office on 2004-01-22 for method of bending a long length of a member and bending apparatus for use in such method.
This patent application is currently assigned to Komatsu, Ltd.. Invention is credited to Itou, Tatsushi, Masumoto, Nobuyoshi.
Application Number | 20040011115 10/395185 |
Document ID | / |
Family ID | 18708239 |
Filed Date | 2004-01-22 |
United States Patent
Application |
20040011115 |
Kind Code |
A1 |
Masumoto, Nobuyoshi ; et
al. |
January 22, 2004 |
Method of bending a long length of a member and bending apparatus
for use in such method
Abstract
The method of bending the long length of the member and a
bending apparatus which are capable of restraining the occurrence
of wrinkles in flanges of the long length of the member, preventing
free end sides of the flanges from buckling, and setting and taking
out the long length of the member easily in bending a long length
of a member in the longitudinal direction, which is approximately
L-shaped or U-shaped in cross section and has a platelike bottom
portion and flanges installed in a standing manner at the end of
the platelike bottom portion, it is to provide. By using an inner
forming assembly forming an inner bent shape of the long length of
the member, an outer forming assembly having a forming pad being
capable of projecting and retracting so as to form an outer bent
shape of the long length of the member and die plate being
rotatable following the forming pad and a sidewall provided in the
longitudinal direction of the outer forming assembly, and by
pressing the long length of the member in the outer forming
assembly with the inner forming assembly and by doing the ironing
of the flanges with the sidewall and the inner forming assembly,
the occurrence of wrinkles in flanges is restrained, and free end
sides of the flanges is prevented from buckling by extending
gradually a bending fulcrum through a retraction of the forming pad
and rotations of the die plates. Further, by installing a moving
mechanism to the sidewall, setting and taking out the long length
of the member is facilitated.
Inventors: |
Masumoto, Nobuyoshi;
(Hirakata-shi, JP) ; Itou, Tatsushi;
(Hirakata-shi, JP) |
Correspondence
Address: |
ARMSTRONG, KRATZ, QUINTOS, HANSON & BROOKS, LLP
1725 K STREET, NW
SUITE 1000
WASHINGTON
DC
20006
US
|
Assignee: |
Komatsu, Ltd.
Tokyo
JP
|
Family ID: |
18708239 |
Appl. No.: |
10/395185 |
Filed: |
March 25, 2003 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
10395185 |
Mar 25, 2003 |
|
|
|
09903861 |
Jul 13, 2001 |
|
|
|
Current U.S.
Class: |
72/381 |
Current CPC
Class: |
B21D 7/066 20130101 |
Class at
Publication: |
72/381 |
International
Class: |
B21D 005/02 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 13, 2000 |
JP |
2000-212298 |
Claims
What is claimed is:
1. A method of bending a long length of a member, wherein, in a
long length of a member having a platelike bottom portion (1) and
flanges (2) installed in a standing manner at the end of the
platelike bottom portion (1), free end sides of the flanges (2)
shrink and platelike bottom portion (1) sides of the flanges (2)
expand, characterized in that, in bending the long length of the
member by using an inner forming assembly (20) forming an inner
bent shape of the long length of the member and an outer forming
assembly (6) forming an outer bent shape of the long length of the
member and by pressing the platelike bottom portion (1) in said
outer forming assembly (6) with said inner forming assembly (20),
said flanges (2) are pressed from both sides thereof between a
sidewall (8) of said outer forming assembly (6) and said inner
forming assembly (20), respectively, and bending is carried out
while doing the ironing of said flanges (2) with said sidewall (8)
and said inner forming assembly (20).
2. A bending apparatus for a long length of a member for carrying
out the bending in which, in a long length of a member having a
platelike bottom portion (1) and flanges (2) installed in a
standing manner at the end of the platelike bottom portion (1),
free end sides of the flanges (2) shrink and platelike bottom
portion (1) sides of the flanges (2) expand, including an inner
forming assembly (20) forming an inner bent shape of the long
length of the member and an outer forming assembly (6) forming an
outer bent shape of the long length of the member, bending the long
length of the member by pressing the platelike bottom portion (1)
in said outer forming assembly (6) with said inner forming assembly
(20), characterized in that said flanges (2) are pressed from both
sides thereof between a sidewall (8) provided in said outer forming
assembly (6) and said inner forming assembly (20), respectively,
and the bending is carried out so as to do the ironing of said
flanges (2) with said sidewall (8) and said inner forming assembly
(20).
3. The bending apparatus for a long length of a member as set forth
in claim 2, the bending apparatus having a forming pad (9) ad die
plates (10) in the longitudinal direction in such a way that said
outer forming assembly (6) forms an outer bent shape of the long
length of the member, characterized in that said forming pad 9 is
installed so as to be capable of projecting and retracting by being
applied with a force toward the direction of said inner forming
assembly (20) by a means (16) of applying a force and the sides of
said forming pad (9) of said die plates (10) are installed
rotatably following a projection/retraction of said forming pad
(9).
4. The bending apparatus for a long length of a member as set forth
in either claim 2 or claim 3, characterized in that the bending
apparatus have a moving mechanism for moving said sidewalls (8)
away from said flanges (2).
Description
DETAILED DESCRIPTION OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a method of bending a long
length of a member being approximately L-shaped or U-shaped in
cross section in the longitudinal direction and a bending apparatus
for use in such method.
[0003] 2. Prior Art and Problems to be Resolved by the
Invention
[0004] It is difficult to form a long length of a member which is
approximately L-shaped or U-shaped in cross section and curved in
the direction of the length thereof as a unity, and therefore, in
conventional method, such a member is manufactured by dividing a
member into a plurality of parts in the longitudinal direction and
by welding the bent parts after bending the dividing parts
separately. That is, as shown in FIG. 9, a long length of a member
having such a shape as described above is manufactured as the whole
member by dividing a member into a member 31 not having the bending
in the longitudinal direction, a member 32 having a largely bending
part in the longitudinal direction and a member 33 having a small
bending part in the longitudinal direction, manufacturing parts
having these divided shapes separately and welding these
manufactured parts. Therefore, to manufacture the long length of
the member having such a shape as described above, many steps are
required and the manufacturing cost becomes high. Accordingly, to
reduce the manufacturing cost of the above-mentioned long length of
the member, it is required to research forming as a unity.
[0005] Currently, as a method of forming a long length of a member
as a unity, there are methods utilizing draw forming or bending
divided into two processes, the bending of the direction of cross
section and the bending of the longitudinal direction. However, in
draw forming, draw forming must be carried out using steel plate
having a dimension sufficiently larger than the steel plate to
which completed products is spread because steel plate must be
restrained in machining, and excessive parts must be eliminated by
laser cutting or plasma cutting after draw forming. Therefore,
there is a defect that material yield decreases in draw
forming.
[0006] Further, a forming object of draw forming is usually a thin
plate (thickness of 0.6 mm to 2.3 mm), it is said that it is
difficult to draw form a thick plate (for example, thickness of 4.5
mm or more). And, if draw forming of the thick plate is performed,
the facilities which have the ability of pressing being capable of
draw forming the thick plate and the molds with the corresponding
high hardness are required, and therefore the cost of equipment
required becomes enormous. Accordingly, it is impossible to reduce
the manufacturing cost in bending the long length of the member
described above by draw forming.
[0007] On the other hand, in a method of bending divided into two
processes, a shape in transverse cross section is first formed by
the bending of a first process, and then a shape in the
longitudinal direction is formed by the bending of a second
process. The bending method of the second process is shown in FIG.
10. The bending of the second process is intended to carry out the
bending by supporting both ends of the long length of the member by
a lower mold 35 forming an outer bent shape of the long length of
the member and by pressing a part to be a largely bending part 43
of the platelike bottom portion 41 of the long length of the member
by an upper mold 36 forming an inner bent shape of the long length
of the member. However, in such a bending method, it is a problem
to cause buckling in free end side of the flanges 42 in which the
large deformation is produced due to contraction. The occurrence of
buckling is remarkable particularly when a long length of a member
is bent to a large extent.
[0008] Accordingly, to reduce the manufacturing cost, it is
required to research a machining method in which, in a method of
bending divided into two processes, buckling does not occur in free
end of flange 42 in bending in the longitudinal direction.
[0009] This invention has been invented to resolve the
above-mentioned conventional defects and it is an object of the
invention to provide a method of bending a long length of a member
and a bending apparatus which are capable of preventing a wrinkle
from occurring in flanges of a long length of a member due to
buckling of free end sides of the flanges in bending the long
length of the member in the longitudinal direction, which is
approximately L-shaped or U-shaped in cross section and has a
platelike bottom portion and flanges installed in a standing manner
at the end of the platelike bottom portion. Also an object of the
invention is to provide a method of bending a long length of a
member and a bending apparatus which are capable of setting and
taking out a long length of a member easily in bending described
above.
MEANS OF SOLVING THE PROBLEMS AND EFFECTS OF THE INVENTION
[0010] And so, a method of bending a long length of a member of
claim 1 is the method of bending, wherein, in a long length of a
member which has a platelike bottom portion 1 and flanges 2
installed in a standing manner at the end of the platelike bottom
portion 1, free end sides of the flanges 2 shrink and platelike
bottom portion 1 sides of the flanges 2 expand, characterized in
that, in bending the long length of the member by using an inner
forming assembly 20 forming an inner bent shape of the long length
of the member and an outer forming assembly 6 forming an outer bent
shape of the long length of the member and by pressing the
platelike bottom portion 1 in the above-mentioned outer forming
assembly 6 with the above-mentioned inner forming assembly 20, the
above-mentioned flanges 2 are pressed from both sides thereof
between a sidewall 8 of the above-mentioned outer forming assembly
6 and the above-mentioned inner forming assembly 20, respectively,
bending is carried out while doing the ironing of the
above-mentioned flanges 2 with the above-mentioned sidewall 8 and
the above-mentioned inner forming assembly 20.
[0011] And, a bending apparatus for a long length of a member of
claim 2 is the bending apparatus for carrying out the bending in
which, in a long length of a member having a platelike bottom
portion 1 and flanges 2 installed in a standing manner at the end
of the platelike bottom portion 1, free end sides of the flanges 2
shrink and platelike bottom portion 1 sides of the flanges 2
expand, including an inner forming assembly 20 forming an inner
bent shape of the long length of the member and an outer forming
assembly 6 forming an outer bent shape of the long length of the
member, bending the long length of the member by pressing the
platelike bottom portion 1 in the above-mentioned outer forming
assembly 6 with the above-mentioned inner forming assembly 20,
characterized in that the above-mentioned flanges 2 are pressed
from both sides thereof between a sidewall 8 provided in the
above-mentioned outer forming assembly 6 and the above-mentioned
inner forming assembly 20, respectively, and the bending is carried
out so as to do the ironing of the above-mentioned flanges 2 with
the above-mentioned sidewall 8 and the above-mentioned inner
forming assembly 20.
[0012] In accordance with the above-mentioned method of bending a
long length of a member of claim 1 and the above-mentioned bending
apparatus for a long length of a member of claim 2, it is possible
to restrain the occurrence of wrinkles effectively, which are going
to be produced at flanges 2 due to bending the long length of the
member. That is, by pressing the platelike bottom portion 1 of the
long length of the member in the outer forming assembly 6 by the
inner forming assembly 20, the deformation that free end sides of
flanges 2 shrink and platelike bottom portion 1 sides of the
flanges 2 expand is produced in the longitudinal direction of the
long length of the member. The wrinkles resulting from buckling are
going to be produced at flanges 2 due to the deformation. However,
since the sidewalls 8 provided in the longitudinal direction of the
outer forming assembly 6 press respective flanges 2 against the
inner forming assembly 20, and the sidewall 8 and the inner forming
assembly 20 do the ironing of the flanges 2, it is possible to
restrain the occurrence of wrinkles.
[0013] And, a bending apparatus for a long length of a member of
claim 3 has a forming pad 9 and die plates 10 in the longitudinal
direction in such a way that an outer forming assembly 6 forms an
outer bent shape of the long length of the member, and is
characterized in that the above-mentioned forming pad 9 is
installed so as to be capable of projecting and retracting by being
applied with a force toward the direction of the above-mentioned
inner forming assembly 20 by a means 16 of applying a force and the
sides of the above-mentioned forming pad 9 of the above-mentioned
die plates 10 are installed rotatably following a
projection/retraction of the above-mentioned forming pad 9.
[0014] In accordance with the bending apparatus for a long length
of a member of claim 3, by pressing the platelike bottom portion 1
of the long length of the member by the inner forming assembly 20,
the forming pad 9 retracts and the sides of the forming pad 9 of
the die plates 10 are rotated to the direction of a retraction of
the forming pad 9, and a bending fulcrum of the long length of the
member is extended gradually toward both ends of the long length of
the member and a largely bending part 3 is formed gradually.
Thereby, since free end sides of the flanges 2 of the largely
bending part 3 shrink gradually, it is possible to prevent free end
sides of the flanges 2 from buckling effectively.
[0015] Furthermore, as the forming pad 9 retracts, the ironing is
applied to each flange 2 of the long length of the member through a
side face of the sidewall 8 and the inner forming assembly 20. As
the forming pad 9 retracts, the sides of the forming pad 9 of the
die plates 10 are rotated to the direction of a retraction of the
forming pad 9, and therefore the flanges 2 applied with the ironing
is extended gradually toward both ends of the long length of the
member and this results in the ironing of the whole flange 2, and
so it is possible to restrain the occurrence of wrinkles
further.
[0016] The bending apparatus for a long length of a member of claim
4 is characterized in that the bending apparatus have a moving
mechanism for moving the sidewalls 8 provided in the longitudinal
direction of an outer forming assembly 6 away from flanges 2.
[0017] In accordance with the above-mentioned bending apparatus for
a long length of a member of claim 4, when the long length of the
member is set to the outer forming assembly 6, the long length of
the member may be set to the outer forming assembly 6 easily since
the sidewalls 8 position on the outer sides, and when bending, the
sidewalls 8 press the flanges 2 against the inner forming assembly
20 and bending is carried out while doing the ironing of the
flanges 2 with the sidewall 8 and the inner forming assembly 20,
and after bending is completed, the long length of the member may
be taken out from the outer forming assembly 6 easily since the
sidewalls 8 move away from the flanges 2.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] FIG. 1 is a perspective view illustrating one example of a
long length of a member being approximately U-shaped in cross
section.
[0019] FIG. 2 shows an outer forming assembly in an embodiment of a
bending apparatus for a long length of a member of the present
invention and FIGS. 2(a) is a top plan view, (b) is a sectional
front elevation view and (c) is a sectional side elevation
view.
[0020] FIG. 3 shows an inner forming assembly in an embodiment of a
bending apparatus for a long length of a member of the present
invention and FIGS. 3(a) is a bottom plan view, (b) is a front
elevation view and (c) is a sectional side elevation view.
[0021] FIG. 4 is a view illustrating in stages the method of
bending the long length of the member of the present invention and
shows a sectional diagrammatic sketch of a machining step at the
start of bending, and FIGS. 4(a) is a sectional front elevation
diagrammatic sketch and (b) is a sectional side elevation
diagrammatic sketch.
[0022] FIG. 5 is a view illustrating in stages the method of
bending the long length of the member of the present invention and
shows a sectional diagrammatic sketch of a machining step
proceeding further than the machining step of FIG. 4, and FIGS.
5(a) is a sectional front elevation diagrammatic sketch and (b) is
a sectional side elevation diagrammatic sketch.
[0023] FIG. 6 is a view illustrating in stages the method of
bending the long length of the member of the present invention and
shows a sectional diagrammatic sketch of a machining step
proceeding further than the machining step of FIG. 5, and FIGS.
6(a) is a sectional front elevation diagrammatic sketch and (b) is
a sectional side elevation diagrammatic sketch.
[0024] FIG. 7 is a view illustrating in stages the method of
bending the long length of the member of the present invention and
shows a sectional diagrammatic sketch of a machining step
proceeding further than the machining step of FIG. 6, and FIGS.
7(a) is a sectional front elevation diagrammatic sketch and (b) is
a sectional side elevation diagrammatic sketch.
[0025] FIG. 8 is a view illustrating in stages the method of
bending the long length of the member of the present invention and
shows a sectional diagrammatic sketch of a machining step at the
end of bending, and FIGS. 8(a) is a sectional front elevation
diagrammatic sketch and (b) is a sectional side elevation
diagrammatic sketch.
[0026] FIG. 9 is a view illustrating a conventional manufacturing
process of the long length of the member being approximately
U-shaped in cross section.
[0027] FIG. 10 is a view illustrating the bending in a second
process of a conventional method of bending in which the bending of
the long length of the member being approximately U-shaped in cross
section is divided into two processes.
EMBODIMENTS OF THE INVENTION
[0028] Next, referring to the drawings, there is illustrated in
detail specific embodiment of a method of bending a long length of
a member and a bending apparatus for a long length of a member of
the present invention. The present embodiment shows the method of
bending a long length of the member A and the bending apparatus for
use in such method as shown in FIG. 1 as one example of a method of
bending a long length of the member and a bending apparatus for use
in such method.
[0029] First, a bending apparatus for a long length of a member A
will be described. The bending apparatus for the long length of the
member A includes an outer forming assembly 6 and an inner forming
assembly 20. Referring to the outer forming assembly 6, FIG. 2
shows the whole view of the outer forming assembly 6 and FIGS. 2(a)
is a top plan view, (b) is a sectional front elevation view and (c)
is a sectional side elevation view. The outer forming assembly 6
has a base 7, sidewalls 8, a forming pad 9 and die plates 10. The
base 7 is approximately rectangular and has a grove 11 extending in
the longitudinal direction at the midsection thereof. A pair of
sidewalls 8 opposed to each other is provided in the groove 11. The
sidewalls 8 are approximately in forms of a landscape rectangular
plate, placed and held on a bottom surface of the groove 11 to be
installed in a standing manner in the transverse direction of the
groove 11 and arranged in such a way that outer side faces of
respective sidewalls 8 abut against inner side faces of the groove
11. The sidewalls 8 are installed in such a way that the height
thereof becomes nearly equal to the height of the side faces of the
groove 11.
[0030] A rectangular cavity 12 extending upward is provided at the
midsection of a bottom face of the groove 11 between the sidewalls
8. The forming pad 9 is inserted movably up and down into the
rectangular cavity 12. The die plates 10 are installed on both
sides of the forming pad 9. Gaps 13 are provided between the
sidewall 8 and the forming pad 9 and between the sidewall 8 and the
die plate 10. The gaps 13 are provided for the sidewalls 8 to move.
The die plates 10 are supported by pins 14 on the outer sides
relative to the base 7 and installed rotatably up and down on the
inner sides. There is the following relation between the forming
pad 9 and the die plates 10 described above. That is, the forming
pad 9 has inclined portions 15 inclined downward on the sides of
respective die plates 10 and respective tips of the inner sides of
the die plates 10 are placed and held on the inclined portion 15.
Therefore, there is the relation that the forming pad 9 sides of
the die plates 10 rotate up and down following up-and-down
movements of the forming pad 9. Further, a spring 16 is installed
at a bottom face of the forming pad 9, and the forming pad 9 is
applied with a force upward. Accordingly, the die plates 10 placed
and held on the inclined portion 15 of the forming pad 9 become a
state that the inner sides of the die plates 10 is rotated upward
since the forming pad 9 sides project upward, and bottom faces of
the die plates 10 and a top face of the base 7 are in the condition
of not contacting. Further, a top face of the forming pad 9 and top
faces of the die plates 10 are installed so as to be lower than the
height of the sidewalls 8.
[0031] FIG. 3 shows the whole view of the inner forming assembly 20
and FIGS. 3(a) is a bottom plan view, (b) is a front elevation view
and (c) is a sectional side elevation view. The inner forming
assembly 20 has a base 21, a punch 22 and wedge plates 23. The base
21 is approximately rectangular and the punch 22 is attached to a
bottom face thereof and a pair of wedge plates 23, 23 are installed
on both sides of the punch 22. The punch 22 has a configuration of
which a midsection projects downward like a mountain, and tip
portion thereof forms an inner shape of the long length of the
member A. Respective wedge plates 23 are approximately in forms of
a landscape rectangular plate and includes the wedge portion 23a
located at a front-end thereof and a restraining portion 23b
located above the wedge portion. The wedge plates 23 are attached
to a bottom face of the base 7 so as to be vertical downward in the
direction of the plate thickness. When the inner forming assembly
20 is fitted into the outer forming assembly 6, the punch 22 is
inserted between the sidewalls 8 of the outer forming assembly 6.
The punch 22 abuts against the top face of the forming pad 9
installed between the sidewalls 8 and the forming pad 9 is lowered
by pressing force of the punch 22. As the forming pad 9 is lowered,
the inner end sides of the die plates 10 are rotated downward and a
bottom face of the die plates 10 abuts against a top face of a base
7 at the lowest end the forming pad 9. In this time, the top face
of the forming pad 9 and the top face of the die plate 10 are
installed so as to form an outer shape of the long length of the
member A. That is the top face of the forming pad 9 has a concave
portion for largely bending in the longitudinal direction and the
top face of the die plate 10 has a concave portion for small
bending in the longitudinal direction.
[0032] Here, a moving mechanism for the sidewalls 8 will be
illustrated. Vertical grooves 17, which are approximately U-shaped
in cross section, extending vertically are formed beside the groove
11 of the outer forming assembly 6. The vertical grooves 17 are
provided to insert the wedge plates 23 installed to the inner
forming assembly 20 into it. On the other hand, tip thickness of
the wedge portion 23a of the wedge plate 23 installed to the inner
forming assembly 20 is set to a dimension smaller than the depth of
the vertical groove 17 and thickness of the restraining portion 23b
is set to a dimension larger than the depth of the vertical groove
17. Further, the difference between the thickness of the
restraining portion 23b of the wedge plate 23 and the depth of the
vertical groove 17 is set so as to become nearly equal to the width
of a gap 13 provided between the sidewall 8 and the forming pad 9
and between the sidewall 8 and the die plate 10.
[0033] When the inner forming assembly 20 is lowered together with
the start of the bending, the wedge plates 23, respectively,
installed to the inner forming assembly 20 are inserted into the
vertical groove 17 provided in the outer forming assembly 6. When
the wedge portions 23a of the wedge plates 23 are inserted into the
vertical groove 17 to some extent, the wedge portions 23a abut
against a bottom face of the vertical groove 17 and side faces of
sidewalls 8. And so, the sidewalls 8, placed and held on a bottom
surface of the groove 11 of a top face of the base 7 and not
secured, move inside gradually.
[0034] Next, a method of bending the long length of the member A
will be described. FIGS. 4 to 8 show sectional diagrammatic
sketches representing in stages the bending of the long length of
the member A. In each drawing, drawing number (a) indicates a
sectional front elevation view and (b) indicates a sectional side
elevation view. First, the long length of the member A formed to
have a predetermined shape in transverse cross section is carried
between the sidewalls 8 of the outer forming assembly 6 with the
free end sides of flanges 2 up and set on the top faces of the
forming pad 9 and the die plates 10 installed between the sidewalls
8. In this time, the sidewalls 8 position on the outer sides, the
forming pad 9 is applied with a force upward by a spring 16
provided at the bottom face of the forming pad 9 and the inner
sides of the die plates 10 are rotated upward following the forming
pad 9.
[0035] By lowering the inner forming assembly 20, the wedge
portions 23a of the wedge plates 23 installed to the inner forming
assembly 20 are inserted into the vertical groove 17 provided in
the outer forming assembly 6. When the wedge portions 23a of the
wedge plates 23 are inserted into the vertical groove 17 by the
specified depth, the wedge portions 23a abut against the bottom
face of the vertical groove 17 and the side faces of sidewalls 8.
On the other hand, the sidewalls 8 are placed and held on a bottom
surface of the groove 11 provided on the top face of the base 7 of
the outer forming assembly 6 and are not secured. Therefore, the
sidewalls 8 are pressed by the wedge portions 23a to move inside
(FIG. 4). And, by lowering the inner forming assembly 20 further,
the restraining portions 23b of the wedge plates 23 installed to
the inner forming assembly 20 are inserted into the vertical groove
17 of the outer forming assembly 6, and the side faces of the
sidewalls 8 are pressed against the side faces of the forming pad 9
and the die plates 10.
[0036] On the other hand, the punch 22 attached to the inner
forming assembly 20 is inserted between the sidewalls 8 of the
outer forming assembly 6 and a tip of the punch 22 is impacted into
the inside of the long length of the member A. By pressing a part
to be a largely bending part 3 of the platelike bottom portion 1 of
the long length of the member A by the punch 22, the long length of
the member A is bent as a bending fulcrum of both sides of a
concave portion for largely bending of a top face of the forming
pad 9. And, the forming pad 9 is lowered and the sides of the
forming pad 9 of the die plates 10 are rotated downward following a
descent of the forming pad 9 by pressing force of the punch 22
(FIG. 5). When the inner forming assembly 20 is lowered further, by
pressing a part to be a largely bending part 3 of the platelike
bottom portion 1 of the long length of the member A by a tip of the
punch 22 keeping the sidewall 8 restrained, the forming pad 9 is
lowered further and the die plates 10 are rotated downward.
Thereby, a bending fulcrum of the long length of the member A is
extended from both sides of a concave portion for largely bending
of a top face of the forming pad 9 to the sides of the die plates
10 depending on bending in the longitudinal direction and a largely
bending part 3 of the long length of the member A is formed
gradually.
[0037] The deformation that free end sides of flanges 2 shrink and
platelike bottom portion 1 sides of the flanges 2 expand in the
longitudinal direction of the long length of the member is produced
by this bending, and the wrinkles are going to be produced
gradually at flanges 2. However, since respective flanges 2 are
pressed against side faces of the punch 22 by side faces of the
sidewalls 8, the occurrence of wrinkles will be restrained (FIG.
6).
[0038] When the inner forming assembly 20 is lowered further, the
tip of the punch 22 presses the platelike bottom portion 1 of the
long length of the member A further while side faces of the
sidewalls 8 press respective flanges 2 against side faces of the
punch 22, the forming pad 9 is lowered and the die plates 10 are
rotated downward. Therefore, the bending fulcrum of the long length
of the member A is extended to both sides of the long length of the
member A. By this bending, and the wrinkles are going to be
produced newly at flanges 2. However, since respective flanges 2
are pressed against the side faces of the punch 22 by the side
faces of the sidewalls 8, the occurrence of wrinkles will be
restrained (FIG. 7).
[0039] Here, as the forming pad 9 is lowered, the ironing is
applied to each flange 2 of the long length of the member A through
the side faces of the sidewall 8 and the side faces of the punch
22. As the forming pad 9 is lowered, the sides of the forming pad 9
of the die plates 10 are rotated downward, and therefore the
flanges 2 applied with the ironing is extended gradually toward
both ends of the long length of the member A and this results in
the ironing of the whole flange 2. Therefore, it is possible to
restrain the occurrence of wrinkles further.
[0040] When the inner forming assembly 20 is lowered further, the
tip of the punch 22 presses the part to be the largely bending part
3 of the platelike bottom portion 1 of the long length of the
member A while the side faces of the sidewalls 8 press the
respective flanges 2 against side faces of the punch 22, the
forming pad 9 reaches at the lowest end and a bottom face of the
die plates 10 abuts against a top face of a base 7. In this time, a
top face of the forming pad 9 and a top face of the die plate 10
form an outer shape of the long length of the member A and the long
length of the member A is forcedly pressed against the top face of
the forming pad 9 and the top face of the die plate 10 by the punch
22. Thereby, the long length of the member A is pressed against a
concave portion for largely bending provided on the top face of the
forming pad 9 and a concave portion for small bending provided on
the top face of the die plate 10, and therefore a largely bending
part 3 and a small bending part of the long length of the member A
are formed in the longitudinal direction and the bending of the
long length of the member A is completed (FIG. 8).
[0041] After the completion of the bending, the inner forming
assembly 20 is raised, the punch 22 is drawn from between the
sidewalls 8 and the wedge plates 23 are drawn from the vertical
groove 17. Accordingly, the sidewall 8 are freed from the
constraints of the wedge plates 23 and the distance between the
sidewalls 8 is expanded outward of itself. Since the distance
between the sidewalls 8 is expanded, the long length of the member
A may be taken out from the outer forming assembly 6 easily after
the completion of the bending.
[0042] In accordance with the above-mentioned method of bending a
long length of a member A and the above-mentioned bending apparatus
for a long length of a member A, it is possible to restrain the
occurrence of wrinkles effectively, which are going to be produced
at flanges 2 due to bending the long length of the member A. That
is, by pressing a largely bending part 3 of the platelike bottom
portion 1 of the long length of the member A by the punch 22
provided in the inner forming assembly 20, the deformation that
free end sides of flanges 2 shrink and platelike bottom portion 1
sides of the flanges 2 expand is produced in the longitudinal
direction of the long length of the member A. The wrinkles are
going to be produced at flanges 2 due to the deformation. However,
since a side face of the sidewalls 8 press respective flanges 2
against a side face of the punch 22, and the side face of the
sidewall 8 and the side face of the punch 22 do the ironing of the
flanges 2, it is possible to restrain the occurrence of
wrinkles.
[0043] And, in the outer forming assembly 6, the forming pad 9 is
applied with a force upward by a spring 16, a means for applying a
force, provided at the bottom face and the die plates 10 supported
by pins 14 are installed on both sides of the forming pad 9. The
die plates 10 are placed and held on an inclined portion 15
provided on the forming pad 9 at a tip of the bottom face thereof
and installed rotatably following up-and-down movements of the
forming pad 9. Therefore, by pressing a part to be a largely
bending part 3 of the platelike bottom portion 1 of the long length
of the member A by the punch 22 installed in the inner forming
assembly 20, the forming pad 9 is lowered and the sides of the
forming pad 9 of the die plates 10 are rotated downward, and a
bending fulcrum of the long length of the member A is extended
gradually toward both ends of the long length of the member A and a
largely bending part 3 is formed gradually. Thereby, since free end
sides of the flanges 2 of the largely bending part 3 shrink
gradually, it is possible to prevent the occurrence of buckling of
the flanges 2 effectively.
[0044] Here, as the forming pad 9 is lowered, the ironing is
applied to each flange 2 of the long length of the member A through
the side faces of the sidewall 8 and the side faces of the punch
22. As the forming pad 9 is lowered, the sides of the forming pad 9
of the die plates 10 are rotated downward, and therefore the
flanges 2 applied with the ironing is extended gradually toward
both ends of the long length of the member A and this results in
the ironing of the whole flange 2, and so it is possible to
restrain the occurrence of wrinkles further.
[0045] Further, each sidewall 8 provided in the outer forming
assembly 6 has a moving mechanism for moving inside. Therefore,
when the long length of the member A is set to the outer forming
assembly 6, the long length of the member A may be set to the outer
forming assembly 6 easily since the sidewalls 8 position on outer
sides, and when bending, the punch 22 is inserted between the
sidewalls 8 and the sidewalls 8 are moved to inner sides by the
wedge plates 23 and abut 2 against the flanges 2, and bending is
carried out while doing the ironing of the flanges 2 with the side
faces of the sidewalls 8 and the side faces of the punch 22, and
after bending is completed, the punch 22 is drawn from between the
sidewalls 8 and the wedge plates 23 are drawn from the vertical
groove 17, and the sidewalls 8 are freed from the constraints of
the wedge plates 23 and move so as to expand the distance between
the sidewalls 8 outward of itself. According, the long length of
the member A may be taken out from the outer forming assembly 6
easily.
* * * * *