JPS5935295B2 - hemming device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a hemming device that can alternately hem multiple types of products with one device.

Hemming is one of the methods of joining plates, in which the edges of a first plate are bent at approximately right angles in advance to form a joint, and a second plate (35 pieces) to be joined to this first plate (in some cases) is After overlapping other boards (which may also be joined at the same time),
The joining portion is bent onto the edge of the second plate to join both plates. This hemming process is widely used in the manufacture of car body components such as doors and bonnets, but conventional hemming devices have often been found to be inconvenient in use. In other words, in recent years, automobile manufacturing plants have adopted a method of arranging various parts manufacturing equipment along the main assembly line, and immediately assembling the parts manufactured by these equipment onto products moving on the main assembly line. 9, moreover, it became possible to run multiple car models on a single assembly line, but the American hemming machines could not process multiple types of parts alternately; When multiple car models are being sent to an assembly line, a number of hemming devices are installed along the assembly line, and workers move between the hemming devices to process various parts and move them along the assembly line. It was necessary to carry the top to the moving product and assemble it. The present invention solves the drawbacks of the prior art, and provides a hemming device that can alternately process multiple types of parts with one hemming device and that allows an operator or an unloading device to take out multiple types of parts at a fixed position. The hemming device of the present invention is characterized by: (a) a lower die for positioning and supporting the first and second plate materials stacked to be joined to each other; , an upper die that is provided with a main bending blade that extends toward the lower die and is moved toward and away from the lower die; and the joint portion is pre-bent to a certain angle prior to processing by the main bending blade. A preliminary bending blade,
The preliminary bending blade is held between the upper mold and the lower mold, and the approaching movement of both molds is moved from a retracted position where the preliminary bending blade does not interfere with the main bending blade to an operating position. a motion converting mechanism for converting the motion to return to the retracted position after preliminary bending; a guide rod extending from one of the upper and lower molds toward the other; and a guide rod provided on the other and sliding with the guide rod. (b) holding an upper mold or a lower mold of the plurality of hemming molds so as to be movable a certain distance upward or downward, respectively; (c) a rotating device that rotates the hemming die around a vertical axis by a fixed angle and sequentially stops at predetermined fixed positions; The pressing member is provided in a fixed position and operates in a substantially vertical direction, and pushes the side of the stopped hemming mold upper and lower molds that is not held by the rotating device. a pushing device that moves the two molds closer together;
The rotating device is provided at a position vertically facing the pushing device with the hemming die in between, and is spaced apart from the hemming die by a predetermined short distance in the vertical direction, and when the pushing device is operated, the rotating device is rotated. and a fixed pressure-receiving member that comes into contact with and supports the mold from behind when the twisted upper or lower mold moves upward or downward a certain distance. It is configured as follows.

That is, in the hemming device of the present invention, the relative positions of the upper mold and the lower mold in the horizontal direction are determined by the guide rod and the guide hole, and the preliminary bending blades are guided by the action of the motion conversion mechanism. It operates in conjunction with the approaching movement of the upper die and the lower die, and performs preliminary bending at an appropriate timing. Therefore, it is no longer necessary to fix the upper die and the lower die to a pressure device, and there is no need for a dedicated drive device such as a hydraulic cylinder to drive the preliminary bending blade. Since it became possible to rotate the hemming mold with a rotating device, it became possible to pressurize multiple types of hemming molds with one pressurizing device. In other words, it has become possible to perform multiple types of hemming processes with one hemming device9, thereby improving productivity in automobile and other manufacturing plants, etc., and saving space for installing the device. This resulted in effects such as lower equipment costs. As mentioned above, the present invention was made for the purpose of providing a hemming device that can suitably supply parts such as doors and bonnets to an automobile assembly line where a plurality of types of parts are directly passed through. Although it has a particularly remarkable effect in this case, it can also be used to supply multiple types of parts, such as front doors and rear doors, even to an assembly line where only one type of car is produced. Furthermore, it is of course possible to apply the present invention to hemming devices for automobile parts.

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be explained in more detail based on the drawings.

1 to 3 show an embodiment in which the present invention is applied to a hemming device for hemming two types of automobile bonnets.

In the figure, 1 indicates a main body frame, and the main body frame 1 has a planar shape of X as shown most clearly in FIG.
Floor beams 2a, 2b, 2e arranged to form a letter shape
, 2d, and connecting beams 2e (Fig. 1), 2f, 2g, and 2h that interconnect the center portions of these floor beams.

At the center of this floor frame 2 is a cylindrical central post 3.
In addition, there are corner posts 4, 5, 6, and 7, one each at the four corners.
Each post is vertically erected, and a ceiling frame 8 is supported by these posts. As shown most clearly in FIG. 2, the ceiling frame 8 includes ceiling beams 8a, 8b, which are arranged in an X-shape in plan view.
8c and 8d, and each of these beams is configured to be parallel to the floor beams 2a, 2b, 2c, and 2d, respectively. Floor frame 2 on 9, posts 3, 4, 5, 6
, 7 and the ceiling frame 8 constitute a frame-shaped main body frame 1. This main body frame 1 constitutes a part of the pressurizing device 10.

That is, a jacking device 11 is attached to the floor frame 2 of the main body frame 1, and four pressure receiving blocks are mounted on the ceiling frame 8 to receive the pressurizing force applied by the jacking device 11 to hemming dies 30, 30', which will be described later. 12 is fixed, so the main body frame 1 is the pressurizing device 10.
It forms the main body of The jacking device 11, as shown in FIGS. 1 and 3, includes a jack 13 and a motor 14 for driving the jack 13. The jack 13 includes a pulley 17 fixed to the shaft end of the motor 14 and a pulley 17 to which the driving force of the motor 14 is transmitted via a belt 16, a pressure shaft 18 (pushing member) that can be raised and lowered in a vertical direction, and a pulley The apparatus is equipped with a mechanism (not shown) for converting the rotational movement of the pressurizing shaft 17 into the vertical movement of the pressurizing shaft 18, but since it is a conventional mechanism, a detailed explanation will be omitted.

The jack 13 is located below the rotation stop position of the hemming molds 30, 30' where the pressure shaft 18 is rotated by a rotation device 20, which will be described later, and is a triangle having the floor beams 2a, 2b as two sides. It is fixed on the substrate 21 so as to be located approximately in the center of the substrate 21. That is, in this embodiment, the hemming dies 30, 301 are rotated with the upper dies supported by the ceiling frame 8 of the main body frame 1, and the jack 13 rotates the hemming dies 30, 301. 30'
The mold on the side that is not supported by the lower mold and the D-ceiling frame 8VC is pushed. The hemming dies 30, 30' are directly supported on the side of the upper die, as will be explained in detail later, but the lower die is kept at a constant distance from the upper die 32 (see Fig. 4) in its supported state. distance? It is made so that it does not separate from the top. Pressure receiving block 1
2 is fixed to the ceiling frame 8 at a position facing the jack 13. The pressure receiving block 12 is the rotating device 2
When the hemming dies 30, 35 rotated by 0 are stopped at the stop position, the pressure receiving surface is located a certain distance above the stopped hemming dies 30, 30'. There is.

In other words, the stopped hemming die 30 and the 3σ upper die 32 come into contact with the upper die 32 only when they move upward a certain distance. The main body frame 1 also constitutes the main body of the rotating device 20. That is, as shown in FIG. 2, the ceiling frame 8 of the main body frame 1 has a moat-shaped running rail 21 that guides the rotation of the hemming dies 30, 30', and a motor that is the power source of the rotation device 20. 2
A bracket 23 for transmitting the power of the motor 22 to the hemming die 30 and 3σ is rotatably attached to the upper part of the center post 3 of the main body frame 1. Together, they constitute the rotation device 20.

The traveling rail 21 is made up of an outer rail 21a and an inner rail 21b, which are formed by bending a channel member so that the grooves face outward, into an annular shape, and is fixed to the ceiling frame 8 in a state where it hangs down from its lower surface. ing. This running rail 21 is connected to an upper base 34 that holds an upper mold 32 of hemming molds 30, 30'.
The roller 53 fixed to the roller 30 is placed inside the groove.
The hemming dies 30, 30' are fitted in such a manner that they can be moved upward by a certain distance, and the hemming dies 30, 30' are rotatably supported. That is, in this example, the rotation device 2
0 holds the upper die 32 of the hemming die so that it can move upward a certain distance and rotates it around the center post 3.
The bracket 23 has half parts 23a and 23b fastened to each other with the center post 3 in between, as shown by the two-dot chain line in FIG.
Each half part 23a, 23b is a buried member consisting of
have engaging protrusions 23c and 23d each having a T-shaped cross section and are formed in a direction parallel to the axis of the center post 3.

The bracket 23 is supported by a flange 3a (see Fig. 1) fixed to the center post 3VC, and can rotate around the center post 39, and a sprocket 24 is bolted to the upper end surface of the bracket 23. ing. The motor 22 is a motor with a built-in speed reducer, and is connected to the ceiling beam 8 of the ceiling frame 8.
It is fixed with the c11C output shaft 22a facing downward.
A sprocket 25 is fixed to the output shaft 22a.
The rotation of the motor 22 is transmitted to the bracket 2 through the sprocket 25, the chain 26, and the sprocket 24.
3. Next, the hemming die 30 will be explained based on FIGS. 4 and 5.

The hemming die 30 includes a lower die 31 and an upper die 32 provided opposite thereto.

The lower mold 31 has positioning members 31a, 31b, etc., and is used to position and support the plate materials to be joined, and is fixed to the upper surface of the lower base 33. On the other hand, the upper mold 32 is fixed to the lower surface of the upper base 34. The upper mold 32 is provided with a main bending blade 32a that extends toward the lower mold 31. The upper base 34 is a substantially rectangular member, and guide tubes (guide holes) 35 are vertically fixed at two diagonal corners of the upper base 34, and a headed rod (guide rod) 36 slides into the guide tube 35. It is movably inserted. This rod 36
The lower end portion of the is fixed to the lower base 33 by a pin 37, thereby determining the relative positions in the horizontal direction of the lower base 33 and the upper base 34, and the lower tab D mold 31 and the upper mold 32. They are connected so that they can be relatively approached and separated. The constant frictional separation between the lower base 33 and the upper base 34 is regulated by the head 36a of the rod 36 coming into contact with the upper surface of the guide tube 35. The hemming die 30 further includes a preliminary bending blade 38 that operates in conjunction with the approach/separation movement between the lower base 33 and the upper base 34, that is, the approach/separation movement between the lower die 31 and the main bending blade 32. .

The preliminary bending blade 38 is fixed to a movable member 39 as shown in FIG.
It is attached to a mounting bracket 43 fixed to the lower base 33. And pins 44, 45 that pivotally connect these to each other,
46 and 47, their axes are located at the vertices of the parallelogram, so the movable member 39 and the pre-bending blade 38 fixed thereto draw an arcuate trajectory while maintaining a vertical posture. It is possible to move. A spring 58 is tensioned between the lever 57 protruding from the link 42 and the lower base 33, so that the movable member 39, preliminary bending blade 38, etc. are always in the state shown in FIG. is biased in the direction of returning to . A roller 48 is also attached to the movable member 39, and this roller is fitted into a cam groove 49a of a cam plate 49 suspended from the upper base 34. This cam groove 49a is located on the lower base 33.
When the upper base 34 and the upper base 34 are brought close to each other, the roller 48
The roller 4 is shaped such that it is moved once toward the center of the hemming mold 30 and then returned to its original position.
8, the links 41 and 42 move to the pins 45 and 4.
7 rotations, the preliminary bending blade 38 draws an arcuate trajectory in the first half of the approach motion between the lower mold 31 and the main bending blade 32 and comes into contact with the lower mold 31 T2, and in the second half, the preliminary bending blade 38 touches the lower mold 31. 31 and retreats to a non-operating position where it does not interfere with the main bending blade 32a. That is, in this embodiment, the preliminary bending blade 39 is movably attached to the lower die 31, and the cam plate 49,
The main bending blade 32a is moved in conjunction with the movement of the upper die 32 and the lower die 31 toward each other by the action of a motion conversion mechanism constituted by the roller 48, the movable member 38 links 41, 42, the mounting bracket 43, etc. Preliminary bending is performed prior to bending. Additionally, in order to simplify the drawing, only one pre-bending blade 38 is representatively shown in FIG. 4, but the hemming die 30 is usually provided with a plurality of pre-bending blades. A9. The above-mentioned hemming die 30, which is configured to be operated in conjunction with the approach of the lower die 31 and the main bending blade 32 by means of cams, rings, etc., is operated by the hanging rib bracket 51. The bracket 2 is suspended from the running rail 21 by the engaging groove 52a.
3 and is attached to the rotation device 20.

Four hanging brackets 51 are fixed to the upper surface of the upper base 34 of the hemming mold 30, and one roller 53 is attached to the tip of each of these hanging brackets 51. By fitting two hemming dies 30 into the grooves of the outer rail 21a and the inner rail 21b of the running rail 21, the hemming molds 30 are hung rotatably along the running rail 21. Further, the engagement/groove 52a fixes members 52b having an L-shaped cross section facing each other to the distal end surface of an engagement frame 52 protruding from the upper base 34 of the hemming mold 30 toward the center post 3 side. In particular, the T-groove is formed by the hemming die 30 and serves to connect the hemming die 30 to the bracket 23 by being engaged with the engaging protrusions 23c and 23d of the bracket 23. When the hemming die 30 is attached to the rotation device 20, the upper base 34 is suspended from the traveling rail 21 by the hanging bracket 51, and the lower base 33 is connected from the upper base 34 by the rod 36. In a suspended state, the lower die 31 and the main bending blade 32 are separated from each other. Even in this state, the lower surface of the lower base 33 is connected to the pressure shaft 1 of the jack 13 in the lowered position.
The dimensions of each part are determined so that it is slightly higher than the tip of 8. Further, four pressure receiving blocks 54 are provided on the upper surface of the upper base of the hemming mold 30. This is for transmitting the strong pressure applied to the hemming die 30 by the jack 13 during the final bending to the pressure receiving block 12 fixedly installed on the ceiling frame 8, and normally both pressure receiving blocks 12 , 54, the hemming die 30 is suspended from the traveling rail 21. Further, a protrusion 55 is provided at the right front corner of the upper base 34, and a cushioning rubber 56 is attached to the tip of the protrusion 55.

On the other hand, a stopper 5a is fixed to the post 5 as shown by the two-dot chain line in FIG. 5, and when the hemming die 30 is rotated counterclockwise in FIGS. 56 comes into contact with this stopper 5a, a limit switch (not shown) attached to the post 5 is activated, the power to the motor 22 is cut off, and the hemming mold 30 is stopped at a position directly above the jack 13. The other hemming die 30' is provided with a similar protrusion and a buffer rubber (not shown) that abuts the stopper 5a from the opposite side 9, and when rotated clockwise in FIG. The hemming die 30' is positioned by coming into contact with the stopper 5a.
The hemming mold 30' has the direction of the protrusion and the cushioning rubber,
Since the hemming die 30 is the same as the hemming die 30 described above except that the shapes of the lower die, main bending blade, and preliminary bending blade are different, detailed explanation will be omitted. 9 Hemming device 1 configured as above
00 is the assembly line 2 for automobile bodies as shown in Fig. 6.
00, the pressurizing device 10 is installed so as to be located on the assembly line 200 side.

Then, the worker M uses the hemming device 100 and the assembly line 20.
You will have to stand between you and 0 to perform the work. Next, this work will be explained together with the operation of the hemming device.

The hemming device 100 of this embodiment has two types of hemming types 3.
Since it is possible to install 0.3σ, the assembly line 20
Two types of hemming types 30 are available depending on the type of car that is used for
Install 30'.

To install the hemming molds 30 and 3σ, attach the half parts 23a and 23b of the bracket 23 to the respective hemming molds 30 and 30.
The rollers 53 attached to the hanging D brackets 51 of the respective hemming dies 30 and 301 are fitted into the running rail 21 while the rollers 53 are engaged with the engagement grooves 52a of the hemming dies 30 and 301, and the half portions 23
This is done by fastening a and 23b with bolts. After installation, when the motor 22 is started, the rotation device 20 is activated, and the dog (not shown) of one hemming die 30 comes into contact with a limit switch (not shown) attached to the main body frame 1, so that the motor 22 is rotated. is stopped, and one hemming mold 30 is positioned in the operating position. With respect to the lower mold 31 of the hemming mold 30 positioned at this operating position, as shown in FIG. 62 are overlapped to form a joint 61a.
3t1 of the pressurizing device 10.
Start 4.

As the motor 14 rotates, the pressure shaft 18 of the jack 13 rises and comes into contact with the lower surface of the lower base 33, causing the lower base 33 to rise. As the lower base 33 rises, the roller 48 for driving the preliminary bending blade rises within the cam groove 49a and is moved toward the center of the hemming die 30 by the cam grooves 4 and 9a.

Along with this movement, the ring 4142 is rotated by the rotation 9 of the pins 45 and 47, and the preliminary bending blade 38 is brought closer to the lower die 31. The preliminary bending blade 38 approaches the lower mold 31 while drawing an arcuate locus as shown by the arrow A in FIG. 7, and as a result, the joint portion 61a of the outer plate 61 is inclined to about 45 degrees. If the lower base 33 is further raised, the rollers 4
8 is moved toward the outside of the hemming mold 30, and as a result, the preliminary bending blade 38 is retracted from the vicinity of the lower mold 31. Thereafter, the lower die 31 further approaches the main bending blade 32, and the main bending blade 32 abuts the joint 61a, which was previously inclined at approximately 45 degrees by the preliminary bending blade 38, and connects it to the inner plate 62. Bend over the edges.

In this case, the upper base 34 is pushed up from its normal position by sliding between the engagement groove 52a and the engagement protrusions 23c and 23d of the bracket 23, and the roller 5 of the suspension 9 bracket 51 is pushed up.
3 floats up from the bottom of the rail 21, and the pressure receiving block 5
4 comes into contact with the pressure receiving block 12 fixed to the main body frame 1, and strong pressure is applied between the lower die 31 and the main bending blade 32, so that the joint portion 62a is completely bent down. Next, when the tongue piece 14 is reversed and the pressure shaft 18 is lowered, the rollers 53 of the hanging rib bracket 51 first contact the traveling rail 21, the upper base 34 stops descending, and the rod 3
The head 36a of the hemming mold 30 comes into contact with the upper surface of the guide cylinder 35, the lower base 33 stops descending, the pressurizing shaft 18 separates from the lower surface of the lower base 33, and the hemming mold 30 returns to its initial state. One cycle of work is completed by removing the ponnet that has been hemmed and pressurized from the hemming mold 30 and attaching it to the body 201 that is moving on the nearby assembly line 200.

If the next body to be flown onto the assembly line 200 is similar, the same bonnet is hemmed using the same hemming die 30 as before without operating the rotation device 20, and then the next body is hemmed. However, if the next body is of a different type, the rotating device 20 is operated in the opposite direction to the previous one, and another hemming die 301 is moved to the operating position.

This movement can be completed in a few seconds with a simple button press.
After the assembly line 200, the operator can remove the different type of bonnet by performing the same operations as the previous one without moving, remaining in the same location, and removing the body part that has been moved close to the body on the assembly line 200. It can be assembled into Next, another embodiment of the present invention will be described with reference to FIGS. 8 to 10.

In this embodiment, the rotating device 70 includes a turntable 71, and the hemming mold is fixed on the turntable 71.
This is largely different from the previous embodiment in that it is constructed so that it can be rotated together with the holder.

That is, in this embodiment, the lower mold of the hemming mold is held and rotated. As is clear from FIG. 8, the turntable 71 connects an outer ring 71a and an inner ring 71b, each of which is made of an annularly curved channel member, with a connecting member 7.
1c, and is rotatably supported by a number of rollers 72. These rollers 72 are rotatably supported by brackets 74 erected on a plurality of radially arranged floor beams 73. A tire 75 is brought into contact with the outer peripheral surface of the turntable 71, and the tire 75 is rotated via a motor 76, a V-belt, and a reducer 78, thereby rotating the turntable 71. I am made to do so.

A pressurizing device 8 is placed in a state that covers a part of this turntable 71.
0 is placed.

That is, two floor beams 81a that also serve as floor beams of the rotation device 70, three posts 81b1 erected from these, and three ceiling beams 81e supported by the posts 81b.
A frame 81 is constructed by 9, and a jack 82 is attached to the intersection of the ceiling beam 81c of the frame 81 so as to push the upper die of the rehemming mold with the pressure shaft 82a facing downward. , a pressure receiving block 8 is attached to the beam 81a on the floor, and contacts the lower mold and supports it from behind.
3 is provided. Note that the jack 82 is driven by a motor 84. In the heather embodiment, three types of hemming types 90, 90', and 9'' are used for the turntable 71.
It is now possible to install it on

Since the hemming molds 90, 90', and 90'1 are almost the same as the hemming mold 30 of the previous embodiment, illustrations and detailed explanations are omitted, but a compression spring is disposed between the lower base and the upper base. Usually hemming type 90,9
0', 9σ5 are kept open and the upper base is operated by being pressed by the jack 82 against this compression spring, which is different from the previous embodiment. It's on. The hemming molds 90, 90', 9'' are attached to the turntable 71 via a plurality of buffer members 85, and are normally not in contact with the pressure receiving block 83, but when pressurized, the buffer members 85 are compressed. Then, the hemming molds 90, 9V, 90 are firmly supported by the pressure receiving block 83, and the turntable 71
This prevents an excessive load from being applied to the The turntable 71 has these three types of hemming types 90, 90', 90
'7 is supported and rotated, but in order to accurately position the desired hemming mold with respect to the pressurizing device 80, the tenth
A positioning device 89 as shown in the figure is provided.

This consists of a lever 92 rotatably attached to a bracket 91 fixed to a fixed member such as a post 81c, a roller 93 pivotally attached to its tip, and an air cylinder 94 for rotating the lever 92. , a dog 95 attached to a lever 92, and a limit switch 96 attached to a bracket 91. When the maintenance lever 71 is rotated with the roller 93 pressed against the outer peripheral side of the turntable 71 by the air cylinder 94, the roller 93 falls into the through hole 71d formed in the turntable 71, and the lever 92 is moved. As the dog 95 rotates, it separates from the limit switch 96 and the power to the motor 76 is turned off, and the tip of the lever 92 fits into the through hole 71d to forcibly stop the turntable 71. Since the method of using the device of this embodiment is almost the same as that of the previous embodiment,
The explanation will be omitted.

Makami: Two representative embodiments of the present invention have been described.
These are merely examples, and it goes without saying that the present invention should not be construed as being limited to these.

[Brief explanation of the drawing]

FIG. 1 is a front sectional view showing an embodiment of the present invention, and FIG. 2 is a plan view thereof. FIG. 3 is a - sectional view in FIG. 1. Figure 4 is the first
FIG. 5 is a detailed front view of the hemming type shown in the figure, and FIG. 5 is a plan view of the main part. FIG. 6 is a schematic plan view showing the arrangement of the apparatus shown in FIG. 1. FIG. 7 is a longitudinal cross-sectional view of a main part of a plate material to be processed by the apparatus according to the present invention. 8th
The figure is a plan view showing another embodiment of the present invention, and FIG. 9 is a front view as well. FIG. 10 is a plan view showing a stopping device used in the apparatus shown in FIG. 8. DESCRIPTION OF SYMBOLS 1... Main body frame, 10... Pressure device, 11... Jacking device,
12... Pressure receiving block, 20... Rotating device, 21...
... Traveling rail, 22 ... Motor, 23 ... Bracket, 30, 30', 90, 9σ, 90'5 ... Hemming mold, 31 ... Lower mold, 32 ... Main bending blade, 38・
...Preliminary bending blade, 51...Hanging rib bracket, 52...
- Engagement frame, 53... Roller, 54... Pressure receiving block, 70... Rotating device, 71... Turntable, 72... Roller, 75... Tire, 76...
Motor, 80... Pressure device, 81... Frame, 8
2... Jacket, 83... Pressure receiving block, 84...
- Motor, 85...Buffer member, 89...Stopping device.

Claims (1)

[Claims] 1. One edge of the plates to be joined to each other is bent at a right angle in advance to form a joint, a second plate is superimposed on the first plate on which the joint has been formed, and the joint is folded into the second plate. An apparatus for performing a hemming process of joining both plate materials by bending them onto the edge of the plate material, the apparatus comprising: (a) a lower die for positioning and supporting the superimposed first and second plate materials; and the lower die. an upper mold that is provided with a final bending blade that extends toward the main mold and is moved toward and away from the lower mold; a preliminary bending blade that preliminarily bends the joint part to a certain angle prior to processing by the main bending blade; It is provided between the upper mold and the lower mold to hold the preliminary bending blade, and controls the approaching movement of both molds by controlling the preliminary bending blade.
a motion converting mechanism that moves from a retracted position that does not interfere with the main bending blade to an operating position, performs the preliminary bending, and then converts the motion to return to the retracted position; (b) a plurality of types of hemming molds each having a guide rod extending toward the other side and a guide hole provided on the other side and slidably fitting with the guide rod; Holding the mold or the lower mold movable a certain distance upward or downward, respectively, and rotating the hemming mold by a certain angle around a vertical axis,
a rotation device that sequentially stops at predetermined fixed positions;
(c) The upper and lower hemming molds are provided with a pushing member that is fixedly spaced apart from the hemming mold that is stopped at the stopped position at a fixed distance in the vertical direction and that operates in a substantially vertical direction. a pushing device that pushes the side of the mold that is not held by the rotation device to bring the two molds closer; and a pushing device that faces the pushing device in the vertical direction with the hemming mold interposed therebetween. A point in time when the upper mold or the lower mold, which is provided at a fixed distance from the hemming mold in the vertical direction and held by the rotating device as the pushing device operates, moves upward or downward by a fixed short distance. and a fixed pressure receiving member that contacts the mold and supports the mold from behind.