JPH0468048B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Field of Industrial Application) The present invention relates to a mold used for bending a plate material. To explain in more detail, the present invention is a split mold in which the mold width can be changed according to the bending width of the plate material, and is particularly effective for use in folding machines such as folding machines, bending machines, and press brakes. Regarding the split type.

(Prior Art) For cabinets, show cases, vending machines, freezers/refrigerators, panels, sinks, switchboards, etc., metal plates whose edges are bent into a U-shape or Z-shape in cross section are used. Normally, in order to bend such a plate material, the short side edge of a workpiece (hereinafter referred to as a blank) that has been cut to a predetermined size is bent, and then this blank is turned in a plane to the inside of the short side bend. It is made by aligning the upper mold with the combined fold width and folding the long side edges. Here, when bending the long side using the wing method, for example, there is a rise due to the bending of the short side that has already been bent, so the clamp mold (upper mold) is
Therefore, it is necessary to prepare a number of upper molds with different mold widths, and to replace the upper mold each time the workpiece width changes, which requires time and effort. It required Moreover, much of this work relies on manual labor, which has been a major bottleneck in automating the bending machine, such as using NC or CNC control. Therefore, there has been a desire for a split type and its replacement device suitable for automatic control.

As a split bending type that meets this demand, for example, the one shown in Japanese Utility Model Application No. 59-44616 is known. As shown in FIG. 4, this mold exchange device consists of an upper mold body 101 attached to the lower end of the ram.
, a split upper mold 102 that is slidable in the mold width direction at the lower part of the upper mold main body 101 , a large number of thin-walled upper molds 103 that are reversible, and a select claw drive mechanism 104 provided at the front part of the upper mold main body. Thin upper mold 103
and a reversing mechanism 105 for reversing a predetermined number of parts, and a select claw 106 moves the portion of the divided upper die 102 that exceeds the machining width to a position outside the machining position.
That is, it is moved outward along the upper mold body 101,
Furthermore, a series of upper molds are formed centered by the width of the inverted thin-walled upper mold 103, thereby making it possible to automatically and easily replace the molds.

(Problems to be Solved by the Invention) However, such a conventional mold changing device uses a group of thin upper molds 103 prepared for the purpose of adjusting values that cannot be divided by one divided upper mold 102. When extracting a desired number of thin-walled upper molds 103 from inside, a predetermined number of thin-walled upper molds 103 are pulled out from the spline shaft 10 with one end of the thin-walled upper mold 103 as a reference.
7, the split molds cannot be distributed symmetrically with respect to a certain reference plane, for example, the center of the machine.

That is, the center of the mold is not always constant, and the thin upper mold 103
Since the center position of the mold moves depending on the selected quantity, it is necessary to align the center of the blank material, that is, the center of the machine, and the center of the mold each time the blank material is fed into the device. It's extremely inconvenient.

In addition, if such a center position correction means is not provided, the gap created between the split upper mold 102 located at both ends and the blank material will be as large as the width of the punched upper mold (usually around 5 mm). As a result, there is a risk that "edge line blur" may occur during the bending process of the blank material.

In addition, this mold changing device selects the split upper mold 102 and the thin upper mold 103 as appropriate, combines them to form an upper mold of a predetermined width, and then connects both sides W ₂ of the already bent blank W. In order to close the mold while avoiding interference, the mold width is temporarily narrowed by retracting the adjustment upper mold 108 and immersing it into the divided upper mold 102. Since it is necessary to return 108 to its original state and widen the mold width to a predetermined width again, a large number of actuators are required, making the device complex and expensive.

Furthermore, each block 102,1 constituting the split type
Since the movement of 03,108 is complicated, NC,
When automating by CNC control or the like, the control program becomes complicated and the probability of occurrence of malfunction increases, which is disadvantageous in terms of automation.

Therefore, the present invention prevents the edge line blurring of the workpiece by automatically distributing the workpiece symmetrically with respect to the center of the processing machine, and the mold width is narrow when going up and down, and when the mold is closed, it automatically returns to the original width. The object of the present invention is to provide a split mold for bending that can be restored in a straight forward manner.

[Structure of the invention]

(Means for Solving the Problems) In order to achieve the above object, the split mold for bending of the present invention is a split mold that is incorporated into a bending device, and has a screw rod along the width direction of the mold. The screw rod has a pair of block bodies screwed together, and a movable piece provided on the outer edge of each block body so as to be able to swing outward in the width direction. A pair of block molds are movable by the same amount in opposite directions along the width direction from the reference plane of the bending device, and have variable mold widths, and a plurality of thin plates divided in the width direction. extracting the segment type and the number of segment types corresponding to the distance between the block types,
and a reversing mechanism for reversing and inserting between the block molds, the reversing mechanism supporting each of the segment molds and connecting to the extracted segment molds to invert only these extracted segment molds. The reversing shaft is connected to the one block mold to hold the entire group of segment molds along the direction toward the other block mold, and is linked to the movement of the one block mold to rotate the entire group of segment molds. a segment holder that moves the block along the reversing axis; and a segment holder that is provided between the reversing axis and the group of segment molds, and a number of segment molds corresponding to the distance from the reference plane to each of the block molds. The split mold for bending is characterized in that it has a segment type selective connection means that selects the same number of segments in opposite directions from the reference plane along the width direction and connects them to the reversal axis.

Further, in the entire group of segment molds, when each of the block molds is located on the reference surface, one end of the group of segment molds that corresponds to the one block mold side is located on the reference surface. The segment type selection connecting means is attached to the reversing shaft, and the segment type selection connecting means is attached to the reversing shaft so that the segment mold, which moves beyond the reference plane as the segment holder moves, is connected to the reversing shaft. A fixed key to be connected, and a segment mold of the same number as the segment molds that are attached to the reversing shaft so as to be movable forward and backward so as to simultaneously move by the same amount in the opposite direction to the moving direction of the segment holder, and that have moved beyond the reference plane. and a movable key that connects the reversing shaft to the reversing shaft.

(Function) In the present invention configured as described above, when changing the mold width, after activating the reversing mechanism and reversing the segment mold, the changing dimension of the mold width is made the same from the center of the mold to the left and right. The pair of blocks are moved so as to be distributed by the amount, and then a segment mold corresponding to the distance between the two block molds is selected and the segment mold is reversed again by the reversing mechanism so that it is inserted between the two blocks. This allows the mold center position to remain constant even if the mold width is changed.
By equally distributing the space between the mold and the workpiece on both sides, it is possible to prevent edge blurring.

In addition, since the block mold has an outer edge that can swing in the width direction, the mold width automatically narrows when the mold is opened and closed, but when processing is performed with the mold closed, the width of the mold narrows. The width of the mold is restored, and interference with the workpiece etc. can be prevented.

(Example) Hereinafter, the configuration of the present invention will be described in detail based on an example shown in the drawings. Note that this embodiment is a case in which the present invention is applied to an upper die of a folding machine.

1A and 1B are front views showing the principle of a split mold for bending according to an embodiment of the present invention;
Figure A shows the state before segment inversion and insertion at the maximum mold width, and Figure 1B shows the state at the minimum mold width. FIG. 2 is a vertical cross-sectional view showing the split mold for bending according to the same embodiment, and FIG. 3 is a vertical cross-sectional view showing the principle of a bending machine to which the split mold for folding according to the same embodiment is applied. It is a diagram.

First, as shown in Figure 3, this bending machine
A blank holder 33 consisting of an upper mold 31 that is attached to a ram 34 and moves up and down, and a lower mold 32 that is fixed to a frame 35 that constitutes the main body of the bending machine.
and a blade 3 that vertically bends the protruding tip edge _W1 of the blank W held by the holder 33.
The rocker arm 37 has a rocker arm 37 disposed at the tip thereof, and drive actuators 38, 39, and 40 for swinging or horizontally moving the arm 37.

One of the molds of the blank holder 33, usually the upper mold 31, is movable up and down to move the blank W in and out, and is configured as a split mold whose mold width can be changed to correspond to the blank width.
As this upper mold 31, the split mold for bending of the present invention can be applied.

As shown in FIGS. 1A and B, the split mold for bending (hereinafter simply referred to as the split mold) is a group of segment molds 1 consisting of thin plates finely divided in the width direction.
A reversing mechanism 3 extracts a predetermined amount of the segment mold 1 and inserts it between the block molds 2A and 2B. The reversing mechanism 3 includes a reversing shaft 4 that supports the segment mold, a segment holder 9 that moves the segment mold 1 along the reversing shaft 4, and a set that selectively connects the reversing shaft 4 and the segment mold 1. selection keys 5A, 5B (corresponding to segment type selection connection means) and the selection key 5
It consists of stoppers 6 and 7 for fixing the segment mold 1 that has come off from A and 5B.

The segment mold 1 consists of thin plates, for example, thin plates with a wall thickness of about 5 mm, which are obtained by dividing a bending mold of a desired shape into small pieces in the width direction (hereinafter simply referred to as the width direction or die width direction), and are stacked in large numbers in the width direction. This forms the main part of the split mold for bending.
This segment type 1 has a processing machine main body, for example, a ram 3.
The rotating mechanism 3 is attached to the reversing shaft 4 of the rotating mechanism 3, which is rotatably supported by the upper die body 8 attached to the upper die body 8, and is supported to swing in a plane perpendicular to the die width direction. A group of segment molds 1 and the above-mentioned reversing shaft 4 are selectively connected by a set of selection keys 5A, 5B, and are in a relationship in which arbitrary numbers are interlocked. Incidentally, this group of segment molds 1 is held by a segment holder 9 constituting the reversing mechanism 3, and is provided so as to be movable in the width direction along the reversing axis 4 as a whole.

The segment holder 9 is attached to the upper mold body 8 with a sliding gib 10, and is provided so as to be slidable in the mold width direction. In addition, the segment holder 9
is connected to one block mold 2A, and holds the entire group of segment molds 1 along the direction toward the other block mold 2B. Therefore, the segment holder 9 is driven by the block mold 2A in conjunction with the movement of one of the block molds 2A, and moves the entire group of segment molds 1 along the reversal axis 4.

Built inside the reversing shaft 4 is a feed shaft 11 that holds a movable key (one of the selection keys) 5B passing through the shaft 4 and feeds it in the width direction. This feed shaft 11 is supported by a cylindrical bearing 12 interposed between it and the reversing shaft 4, and is provided so as to be movable only in the axial direction by a sliding key 13 mounted between them. ing. A first screw rod 15 is screwed into the hollow portion 14 at the tip of the feed shaft 11, and is provided so as to be movable in the width direction as the screw 15 rotates. In addition, in order to allow the movable key 5B to move in the axial direction, the reversing shaft 4
is provided with a long groove 16 in the axial direction, and is provided so that the movable key 5B can be accurately moved in the width direction, that is, in the axial direction of the reversing shaft 4, using the long groove 16 as a guide. Further, a gear 17 is fixed to one end of the reversing shaft 4, and meshes with a rack rod 18 driven by a hydraulic cylinder (not shown). Therefore,
The reversing shaft 4 is rotated by a predetermined angle, for example, 180°, by linear drive of a hydraulic cylinder.

A pair of block molds 2A and 2B located at both ends of the segment mold 1 described above are each supported by a second screw rod 19 rotatably supported by the upper mold body 8, and are slidable against the segment holder 9. By being slidably fitted together via the dynamic gib 27, as the second screw rod 19 rotates, it is possible to move the same amount in opposite directions from the mold center O at the same time in the width direction. It is set in. Block types 2A and 2B are block main body 2
0 and a movable piece 21 which is attached so as to be swingable in the mold width direction, and the mold width can be varied by making the movable piece 21 constitute the outer edge of the block molds 2A and 2B. This is what I did. That is,
The movable piece 21 is attached to the block body 20 with a pin 22 so as to be swingable in the width direction, and is normally urged toward the blank W side, that is, downward, by a compression coil spring 23, and is oriented substantially vertically. Therefore, when the mold is closed, the movable piece 21 contacts the blank W and rotates so as to be pushed outward, so the width of the block molds 2A and 2B is the same when the mold is closed and when the mold is opened. Unlike , it only restores its original size when the mold is closed. Here, the movable piece 21 has front and side upper surfaces 21a, 2
1b forms an inclined surface and is provided so as not to interfere with the bent blank front edge _W1 and side edge _W2 . The movable piece 21 is attached so that its bottom surface is flush with the block body 20 when the mold is closed, and the inclined surface 21a and side inclined surface 21b portions respectively protrude from the block body 20.

The second screw rod 19 that supports the block molds 20A and 20B has opposite threads of the same pitch on the left and right sides, and its rotation causes the left and right block molds 2A and 2B to approach or separate from each other, respectively. give movement. This second screw rod 1
9 and the first screw rod 15 are connected by a timing belt 24 and rotated synchronously by the rotation of a drive motor 25. Therefore, the inversion axis 4
The screws of the first screw rod 15 and the second screw rod 19 on the left side in the figure are cut at the same pitch and in the same direction, and the movable key 5B and the block type 2B on the left side in the figure are cut in the same direction and by the same amount at the same time. It is designed to be moved.

Further, a stopper 6 is attached to the upper mold body 8 to prevent the segment mold 1 released from the selection keys 5A, 5B from freely rotating toward the block molds 2A, 2B. The stopper 6
is a sliding key that fits into a notch 26 formed on the back side of the segment mold 1, and when all the segment molds 1 are at their maximum width when they can be reversely inserted between the block molds 2A and 2B, that is, when all the segment molds 1 are is the center of the mold O
(1st
(see Figure A), and extends to the position closest to segment type 1 on the left end. Therefore, stopper 6
is in such a relationship that it slides into the aforementioned notch 26 and restrains the segment mold 1 at the same time as the left end segment mold 1 is removed from the selection keys 5A, 5B. A stopper 7 is also provided on the block mold 2B.
The stopper 7 is arranged between the tip of the stopper 7 and the machine center O when the segment type 1 is pressed against the selection key 5.
It prevents free rotation when removed from A, 5B, and is a quarter-circle shaped receiver integrally formed with block mold 2B. Although these stoppers 6 and 7 are effective for inverting and inserting only the desired number of segment molds 1, they can also be replaced with means such as increasing the inversion angle to prevent rotation due to their own weight.

As shown in FIG. 1B, the group of segment molds 1 as a whole is arranged so that when each of the block molds 2A and 2B is located at the mold center O, one block of both ends of the group of segment molds 1 is formed. Type 2
It is held by the segment holder 9 so that one end corresponding to the A side is located at the mold center O.

Selection key 5 as segment type selection connection means
A, 5B are provided between the reversing shaft 4 and a group of segment molds 1, and are connected to each block mold 2 from the mold center O.
The same number of segment molds 1 corresponding to the distances A and 2B are selected in mutually opposite directions from the mold center O along the width direction and connected to the reversing shaft 4.

More specifically, the selection keys 5A and 5B are a type of sliding keys that can slide smoothly relative to the segment mold 1, and in FIG. Fixed key 5A located on the left side, and movable key 5 located on the left side
It consists of B. The fixed key 5A is fixed to the reversing shaft 4, and connects the segment mold 1, which has moved to the right in the figure beyond the mold center O with the movement of the segment holder 9, to the reversing shaft 4. On the other hand, when the group of segment holders 9 move in the width direction in conjunction with the block mold 2A, the movable key 5B is attached to the reversing shaft 4 so that the segment holders 9 simultaneously move by the same amount in the direction opposite to the direction of movement of the segment holders 9. It is attached so that it can move forward and backward. In addition, since this movable key 5B moves in the opposite direction by the same amount as the movement amount of the segment holder 9, the same number of segment molds 1 as the segment molds 1 that have moved to the right side in the figure beyond the mold center O can be moved on the reversing axis. It will be connected to 4.

Therefore, when the group of segment holders 9 move in the width direction in conjunction with the block mold 2A, the segment mold 1, which is moving to the right in the figure from the mold center O, is moved to the reversing axis 4 by the fixed key 5A. The quantity of segment mold 1 located on the left side in the figure from the mold center O and connected by fixed key 5A is the same number of segment types 1
is connected to the reversing shaft 4. In this way, the same amount of segment molds 1 are extracted from the machine center O in the left and right directions in the figure.

Note that the above-described embodiment is merely an example, and can be modified as appropriate without departing from the gist of the present invention. For example, the reversing mechanism 3 may have a plurality of selection keys 5A, 5B, and may be replaced with spline shafts or the like. In addition, the segment type selective connection means of the reversing mechanism 3 is connected to a segment type 1 that arbitrarily protrudes in the radial direction.
A selection key having the same width as the segment mold 1 may be selectively connected to the reversing shaft 4 by a member that protrudes the same amount left and right from the center of the mold toward the end. . Further, in this embodiment, the movable piece 21 using the spring 23 is biased to ensure rotation toward the blank W side.
It may be configured to rotate by its own weight or other elastic members may be used.

Although the above embodiment is an example applied to a folding machine, it can also be adopted as a split mold for other folding machines such as press brakes and bending machines.

Next, the operation of this embodiment will be explained.

According to the split die configured as described above, the bending process of the plate-shaped workpiece W can be carried out with a simple operation as follows.

For example, a width of 700mm with both edges already bent,
To explain the case of bending the tip edge of a plate-shaped blank W with a plate thickness of 0.5 mm, the die width l of the upper mold is l = L-2t-2α, where L: blank outer width t: plate thickness α: 〓 (equal distribution on both sides), and l + 2α = 700 - (2 x 0.5) = 699 mm. In this case,
The maximum width of block types 2A and 2B shall be 200mm.
Therefore, the maximum width of block molds 2A and 2B at both ends is 200 mm.
By subtracting mm x 2, 299 mm becomes the maximum width of segment type 1. Here, if the width direction dimension of one segment mold is 5 mm, the desired number of segment molds is 299.
÷5 = 59.8 pieces, but round down the fractional 0.8 pieces.
Assuming 59 sheets, α=2/1 {700−(2×200)−(2×0.5)−
(59×5)}=2mm, but a distance of about 2mm does not pose a problem for practical bending work. Note that the mold width l is cut off at a pitch of 5 mm, which is the thickness of one segment mold.

To extract the segment mold 1, the entire segment mold 1 is moved to the left in the figure by rotating the first and second screw rods 15 and 19 by a predetermined amount according to a program in advance, and at the same time the movable key 5B is moved in the figure. Move it to the upper right side by the same amount, and discard 59 pieces of segment mold 1, 147.5 mm each on the left and right from the center O of the processing machine. The segment mold group 1 on the left side, which is removed from the selection keys 5A and 5B, immediately engages with the stoppers 6 and 7 attached to the upper mold body 8 or the block mold 2B, and free rotation is prevented.

After a predetermined number of segment molds 1 are selectively extracted from a group of segment molds 1, the drive cylinder at one end of the reversing shaft 4 is operated, and the reversing shaft 4 is rotated by a predetermined angle, usually 180°, to form the extracted segment molds. Reverse the group. At this time, the block molds 2A, 2 at both ends
B is also moved by the same amount in opposite directions by the action of the second screw rod 19 which is rotated synchronously by the timing belt 24, so that the width of the extraction segment mold 1 is the same as the mold width. It is provided.
Therefore, the extracted segment mold 1 is inverted and inserted between the block molds 2A and 2B to form an upper mold of a predetermined width. At this time, the segment mold 1 that is inverted comes into contact with the sliding gib 27 attached to the segment holder 9, and is positioned.

Thereafter, when the upper mold 31 is lowered by the operation of the ram 34, the mold is closed and clamps the plate blank W placed at a predetermined position. At this time, the movable pieces 21 of the block dies 2A and 2B at both ends of the lowering upper die 31 are pushed down toward the lower die 32 by the action of the spring 23, reducing the die width, so that the sides of the blank W are Bending edge W ₂ is block type 2A, 2B at both ends
The mold can be inserted without interfering with the Block type 2 that avoids the side bending part W ₂ of the blank W
In the case of A and 2B, the movable pieces 21 come into contact with the blank W and are relatively pushed upward, so that they are automatically expanded to the original mold width and sandwich the blank W. Therefore, after extracting the desired number of segment molds 1 and inserting them between the block molds 2A and 2B, the upper mold can be simply lowered without interfering with the side edge _W2 of the bent blank W. The mold can be closed and an upper mold of a predetermined width can be constructed. Furthermore, in this device, the upper mold length is always distributed in equal amounts to the left and right sides of the machine center O, so there is no need to perform alignment with the mounted blank W.

After the mold is closed, the tip of the blank is bent into a predetermined shape by swinging the bending arm 37. After the predetermined bending process, the entire upper mold 31 is slightly raised,
Push the blank W forward and make block molds 2A, 2.
After making sure that the front inclined surface 21a of B does not interfere with the front edge _W1 of the blank that is bent at the time of raising, the blank is raised again to the rising end. Then, prepare for the next processing.

Incidentally, when the cylinder, drive motor 25, etc. are operated by, for example, NC control or CNC control, this type of work can be automated.

〔Effect of the invention〕

As is clear from the above explanation, according to the split mold for bending of the present invention, the center of the processing machine and the center of the mold can be automatically aligned regardless of the mold width, and therefore the blank By positioning and feeding the blank in advance, you can perform the bending process without centering at the same time as inserting the blank.
This makes it possible to prevent edge line blurring from occurring.

In addition, this split mold automatically narrows the mold width when closing and cutting the mold, and restores the original width only when the mold is closed.
To extract and invert appropriate quantities from a group of segment molds without having to perform troublesome operations such as temporarily pulling out a part of the mold to avoid interference with the edges of an already bent blank. This makes it possible to hold a blank with a simple movement of forming a mold of a desired width and then lowering it in that state.

For this reason, if various information about the blanks that are sequentially flown, such as dimensions, shapes, bending conditions, work procedures, etc., is memorized and controlled by NC or CNC, the mold can be changed immediately after one bending operation is completed. It is possible to knit it to a desired width and proceed to the next bending process, making it possible to efficiently produce a wide variety of products in small quantities.

Moreover, the movement of the mold is simple, reversing and moving in the width direction, and there are few moving parts, so fewer actuators are required, reducing costs.
Facilitate automation through control, etc.

[Brief explanation of the drawing]

FIG. 1 is a principle diagram showing an embodiment of the split mold for bending according to the present invention when viewed from the front, where A shows the state before segment inversion and insertion at the maximum mold width, and B shows the state of the minimum mold width. show. FIG. 2 is a cross-sectional view of the same split type. FIG. 3 is a principle diagram showing the outline of a folding machine to which the split mold of the present invention is applied, and FIG. 4 is a front view showing the outline of a conventional split mold. 1...Segment type, 2A, 2B...Block type,
3... Reversing mechanism, 4... Inverting axis, 5A, 5B... Selection key (segment type selection connection means, 5A... Fixed key of selection key, 5b... Movable key of selection key), 9...
Segment holder, 15, 19... Screw rod, 20... Block body, 21... Movable piece, 23...
Spring, O... Machine center, mold center (reference plane).

Claims (1)

[Scope of Claims] 1. A split mold incorporated into a bending device, which includes a pair of block bodies 20, 20 screwed to a screw rod 19 along the width direction of the mold, and each of these block bodies 20, A movable piece 2 is provided on the outer edge of 20 so as to be able to swing outward in the width direction.
1 and 21, which are movable by the same amount in opposite directions from the reference plane O of the bending device along the width direction as the screw rod 19 rotates, and whose mold width is variable. extracting a pair of block molds 2A and 2B, a large number of segment molds 1 made of thin plates divided in the width direction, and a number of segment molds 1 corresponding to the distance between the block molds 2A and 2B, It is composed of a reversing mechanism 3 that is inserted between the block molds 2A and 2B, and the reversing mechanism 3 supports each of the segment molds 1 and is connected to the extracted segment molds 1 so that the segment molds 1 are connected to the extracted segment molds 1. an inversion shaft 4 for inverting only the segment mold 1;
a segment holder 9 that holds the segment molds 1 along the direction toward B and moves the entire group of segment molds 1 along the reversal shaft 4 in conjunction with the movement of the one block mold 2A; and the reversal shaft 4. A number of segment molds 1, which are provided between the group of segment molds 1 and corresponding to the distance from the reference surface O to each of the block molds 2A and 2B, are placed between each other along the width direction from the reference surface O. Select the same number in the opposite direction and rotate the reversal axis 4.
Segment type selective connection means 5 connected to
A split mold for bending processing, characterized by having A and 5B. 2. The group of segment molds 1 as a whole has one end corresponding to the one block mold 2A side among both ends of the group of segment molds 1 when each of the block molds 2A and 2B is located on the reference plane O. is held by the segment holder 9 so as to be located on the reference plane O, and the segment type selection connecting means 5A, 5B are attached to the reversing shaft 4, and as the segment holder 9 moves, the segment type selection connecting means 5A and 5B a fixed key 5A that connects the segment mold 1 that moves beyond the reversing shaft 4 to the reversing shaft 4; The same number of segment molds 1 as the segment molds 1 that have been attached to and moved beyond the reference plane O
The split mold for bending according to claim 1, further comprising a movable key 5B that connects the reversing shaft 4 to the reversing shaft 4.