JP2582746B2 - Method for manufacturing curved vent pipe and manufacturing apparatus used for the method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bent pipe having a straight portion at both ends of a bent pipe used for an air conditioner or the like. The present invention relates to a manufacturing method and an apparatus for assembling the flange provided in the above by winding.

[0002]

2. Description of the Related Art Conventionally, when manufacturing a curved vent pipe of this type, since the curved bent pipe and the straight section are combined, as shown in FIG. 16, for example, as shown in FIG. A work (c) and (d) having a shape divided into two by the (a) and the outer peripheral wall (b) is manufactured, and the work (c) and (d) are tied together and the mating surface is welded. I was

[0003]

However, in the conventional welding method as described above, since the method has to be performed manually, there is a limit on the improvement of the production efficiency and the cost is high. In addition, according to the welding, the works (c) and (d) are burnt and the appearance is impaired.

The present invention has been made in view of such a point, and an object of the present invention is to form a flange integrally provided on a mating surface of a workpiece by winding and joining it. An object of the present invention is to eliminate the need for a welding operation, to automate the production of a bent vent pipe having straight portions at both ends, and to finish the appearance beautifully. It is another object of the present invention to propose a manufacturing apparatus suitable for the manufacturing method.

[0005] When the inner and outer peripheral walls of the bent vent pipe are subjected to the winding process by applying an external force as described above, it is necessary to support the processed portion of the workpiece from the inside. In that case,
It is conceivable to support the inner surface of the processed portion of the work by a jig or the like that has entered through the opening of the work. However, it is very difficult for the bent vent pipe to enter or retract the jig.

In view of the above, the present invention provides a method in which a core is made to penetrate from both ends of a work and is brought into contact with an inner surface of a processed portion of the work so as to support the same. The object of the present invention is to appropriately deform the gold so as to make good contact with the gold, thereby securely supporting the inner surface of the processed portion of the work.

[0007]

According to a first aspect of the present invention, there is provided a method for manufacturing a bent vent pipe having straight portions at both ends. A work in which the inner and outer peripheral walls are divided into two parts and a flange is integrally formed at the divided part is held together, and then a metal core is made to penetrate from both ends of the work, and the ends are separably connected to be brought into contact with the inner surface of the processed part. Then, a part of the metal core is protruded and brought into contact with the remaining portion of the inner surface of the processed portion, and then the flange is continuously and laterally lowered from both ends of the inner peripheral wall flange and the outer peripheral wall flange. It is configured to perform winding processing.

Further, the manufacturing apparatus according to claim 2 is provided with a pair of metal cores which respectively enter from both ends of the vent pipe and are connected so that their tips can be separated from each other. The fixed support portion to be in contact is formed so as not to interfere with the vent pipe when the core metal enters, and a movable support portion that protrudes from the core metal so as to be able to return from the core metal at the time of connection and abuts on the remaining portion of the inner surface of the processing portion is provided. And a guide slot having a predetermined width extending along the work dividing surface is provided in the frame plate, and a driven arm is arranged on the work side of the frame plate. A pin which is slidably fitted to the guide long hole is connected to the arm, and a drive arm which has a long hole into which the pin is fitted on a side opposite to the work of the frame plate and is rotated by a driving means is supported. And the above frame A plate, provided with a guide portion for guiding the movement of the driven arm, to the follower arm, a structure for supporting the roller for pressing the flange of the workpiece.

Further, the manufacturing apparatus according to claim 3 is the same as the manufacturing apparatus according to claim 2.
In the manufacturing apparatus described above, the guide elongated hole is formed in an arc shape around the rotation center of the drive arm, the pin is connected to the drive arm instead of the driven arm, and the elongated hole into which the pin is inserted is driven instead of the drive arm. This is a configuration formed on the arm.

[0010]

According to the first aspect, when the core is penetrated into the work and connected thereto, the core comes into contact with and supports the inner surface of the processed portion. During this time, the core does not interfere with the work because part of the core has not yet protruded. Next, when a part of the core metal approaches, it comes into contact with and supports the remaining portion of the inner surface of the processed portion. afterwards,
The work is continuously joined by the flange being tightened. After the work is processed, the protruding portion returns to the metal core, the metal core is separated, and each metal core is retracted from both ends of the work.

According to the second and third aspects of the present invention, when the metal core is inserted from both ends of the work and connected to each other, the fixed support portion comes into contact with and supports the inner surface of the processing portion. Next, when the moving supporting portion approaches the core metal, the moving supporting portion contacts and supports the remaining portion of the inner surface of the processing portion. Thereafter, when the drive arm is rotated by the drive means, the driven arm is driven via the pin.
In that case, the driven arm moves along the work division surface because the pin slides along the guide elongated hole and the guide guides. Therefore, the roller continuously presses and winds the flange of the work from the end. After the work is processed, the movable support returns to the metal core, the metal core is separated, and each metal core is retracted from both ends of the work.

[0012]

Embodiments will be described below. As shown in FIG. 14, the curved vent pipe V manufactured in the embodiment has straight portions Sa, Sb at both ends, and has two half-split workpieces L, which are divided into two by an inner peripheral wall and an outer peripheral wall. R are tied together, and the flanges Lf, Rf of the mating surfaces are joined by winding and working. 1 to 3 show a manufacturing apparatus according to an embodiment for performing a series of manufacturing processes.

In these figures, reference numeral 10 denotes a thick frame plate, and works L and R set on one side thereof.
Are set up substantially in parallel to the dividing plane. X is a first metal core fixed to the frame plate 10 via the fixing bracket 13, and Y is a second metal core connected to the frame plate 10 via an actuator 14 such as an air cylinder which reciprocates in the horizontal direction. The first core metal X and the second core metal Y penetrate both ends of the workpieces L and R, respectively, and contact the inner surfaces of the processed portions to support the workpieces L and R. The frame plate 10 is provided with a guide elongated hole 15 having a fixed width along the work dividing surface. A driven arm 20 made of a box-shaped steel material is arranged on the work side of the frame plate 10. A pin 21 is fitted in the middle of the driven arm 20, and the pin 21 is slidably fitted in the guide slot 15. A drive arm 30 made of a thick plate is rotatably supported by a support shaft 31 on the opposite side of the work from the frame plate 10, and a gear 32 is fixed to the support shaft 31. An elongated hole 33 is formed at the tip of the drive arm 30, and the pin 2 is inserted into the elongated hole 33.
1 is inserted. Reference numeral 40 denotes a driving means,
1, a gear 42 supported by the frame plate 10 and engaged with the gear 32 of the support shaft 31, and a motor 41 and a chain 43 bridged over the gear 42. , 32 via the drive arm 3
0 is rotated.

The frame plate 10 is provided with guide portions 50 and 60 for guiding the movement of the driven arm 20. First, the torque guide 50 will be described.
The frame plate peripheral edge 16 on the outer peripheral side of the work curved portion in the frame plate 10 is formed in a shape corresponding to the guide elongated hole 15.
1 is provided. The guide rail 51 is formed by fixing a side plate-shaped bottom plate 51a along the frame plate peripheral edge 16 and two vertical walls 51b arranged in parallel on the bottom plate 51a. On the other hand, an arm 52 extending laterally is provided at one end of the driven arm 20, and a tip of the arm 52 is fitted between the vertical walls 51 b of the guide rail 51 and comes into contact with the side of the vertical wall 51 b. The two pieces 53 are pivotally supported at a predetermined distance in the moving direction of the driven arm 20. Next, the tracking guide 60 will be described. As shown in FIG. 4, a pair of rails 6 extending in the vertical direction and then bending in the horizontal direction are provided on the work side of the frame plate 10.
1a and 61b, and a pair of rails 65a and 65b which extend in the vertical direction in parallel with this and then bend in the horizontal direction by a quarter turn are provided. On the work side, the rails 61a, 61
b and 65a, 65b each have six engaging portions.
2, 66 are provided.

Rollers 71a, which press the flanges Lf, Rf of the workpieces L, R onto the driven arm 20,
71b, 72a, 72b are pivotally supported. Roller 71
a, 71b are the inner peripheral wall flanges Lf, Rf of the workpieces L, R
And press the roller 72a,
Reference numeral 72b is configured to press the outer peripheral wall flanges Lf, Rf of the works L, R from both sides.

The first metal core X and the second metal core Y will be described in detail with reference to FIGS. As shown in these drawings, both the first metal core X and the second metal core Y include fixed support portions 122 and 132 and movable support portions 123 and 133. In the case of the first metal core X, the fixed support portion 122 is made up of first to third members made of a thick plate having a curved shape, and one end of the first member 122 a
And the second member 122b is attached in parallel with the first member 122a with a gap, and the third member 122c
Is attached to the outer peripheral side of the curved portion between the first member 122a and the second member 122b. The end surface 122 ′ of the fixed support portion 122 on the outer peripheral side of the curved portion is formed so as to uniformly contact the inner surface of the processed portion of the outer peripheral wall of the vent pipe when the core metal is connected. Further, the end surface 12 on the inner peripheral side of the curved portion
2 ″ is formed so as to come into contact with the inner surface of the straight portion Sa in the processed portion of the inner peripheral wall of the vent pipe when the cored bar is connected. With this configuration, the fixed supporting portion 1
22 does not interfere with the curved vent pipe V.
On the other hand, the second mandrel Y has the same structure as the first mandrel X except that the first member is fixed to the actuator 14 instead of the fixing member 13. That is, the fixed support portion 132 having the first member 132a, the second member 132b, and the third member 132c is provided.
The outer peripheral end surface 13 of the curved portion of the fixed support portion 132 when the cored bar is connected.
2 ′ is formed so as to evenly contact the inner surface of the processed portion of the outer peripheral wall of the vent pipe, and the inner end surface 132 ″ of the curved portion is in contact with the inner surface of the straight portion Sb of the processed portion of the inner peripheral wall of the vent pipe. The fixed support portion 132 does not interfere with the bent vent pipe V when the core metal enters. The tips of the first metal core X and the second metal core Y are formed in a shape such that when the two metal cores X and Y penetrate from both ends of the curved vent pipe V and abut against each other, they are separably joined to each other. ing.

Then, in the first metal core X, the first member 1
On the inner peripheral side of the curved portion between the second member 122b and the second member 122b,
A movable support portion 123 made of a thick plate having a curved shape is disposed, and an end of the movable support portion 123 on the side of the fixing bracket is provided with a pin 123a.
22a and the second member 122b. Therefore, when the tip of the movement support portion 123 swings around the pin 123a, the movement support portion 123
It is configured to be housed between the second member 122a and the second member 122b or to protrude from the space therebetween. The end surface 123b on the inner peripheral side of the curved portion of the moving support portion 123 is formed so as to uniformly contact the inner surface of the processed portion of the inner peripheral wall of the vent pipe when protruding. Further, a spring 124 is mounted between the third member 122c and the movement support portion 123, and slightly biases the movement support portion 123 in a direction to approach. On the other hand, the second mandrel Y also has a structure similar to that of the first mandrel X, has a moving support portion 133 that swings around the pin 133a, and an inner peripheral end face of the moving support portion 133 on the curved portion. 133b is formed so as to uniformly contact the inner surface of the processed portion of the inner peripheral wall of the vent pipe when the moving support portion 133 is protruding, and a spring 134 is provided between the third member 132c and the moving support portion 133. It is installed. further,
At the end of the fixed support portion 122 of the first metal core X, an extruding pin 125 is provided so as to be able to move in a direction along a joining line between the first metal core X and the second metal core Y. A cam portion 132d for pushing out the pushing pin 125 is formed at the tip of the fixed support portion 132 of the gold Y. Therefore, when the first metal core X and the second metal core Y intrude from both ends of the curved vent pipe V and abut against each other, the pushing pins 12
5 is pushed by the cam portion 132d and is pushed inward, whereby the moving support portions 123 and 133 protrude and are held so as not to be stored.

Next, the operation of the manufacturing apparatus will be described. First, as shown in FIG. 7, in a state where the actuator 14 is contracted and the second metal core Y is retracted in the horizontal direction so as to be separated from the first metal core X, as shown in FIG. Work L and R are set together. At this time, the curved portion outer peripheral end surface 122 ′ of the fixed support portion 122 of the first metal core X uniformly contacts the inner surface of the processed portion of the vent pipe outer peripheral wall, and the curved portion inner peripheral end surface 122 ″ is formed inside the vent tube. Of the processed portions of the peripheral wall, the inner wall of the straight portion Sa is in contact with the inner surface of the straight portion Sa. However, both of the moving support portions 123 and 133 are in the housed state, so that the first metal core X and the second metal core Y are bent.
There is no interference with. Next, when the actuator 14 is extended to advance the second mandrel Y in the horizontal direction and is connected to the first mandrel X as shown in FIG.
25 functions to squeeze the moving support portions 123 and 133, so that the curved support inner peripheral end surface 12 of the moving support portions 123 and 133.
3b and 133b uniformly contact the inner surface of the processed portion of the inner peripheral wall of the vent pipe. Thus, the processed portion of the vent pipe V is completely supported by the first metal core X and the second metal core Y.

When the drive arm 30 is rotated by operating the motor 41, the driven arm 20 is driven via the pin 21 as shown in FIG. In this case, since the pin 21 slides along the guide slot 15 and the guide portions 50 and 60 guide the driven arm 20, the driven arm 20 moves along the work dividing surface. Therefore, the rollers 71a, 71
b and 72a, 72b are the flanges Lf of the workpieces L, R,
Rf is continuously pressed from the end and tightened. In this case, first to third sets of rollers 71a and 71b and 72a and 72b are prepared according to the stage of the tightening process. As the stage progresses, the set of rollers is replaced with the next set. We will proceed with the winding process. That is, it is set so that the tip of one flange Lf covers the other flange Rf. Then, first, as shown in FIG. 11, the tip of the flange Lf is bent by approximately 90 degrees with the first roller set and turned down to sandwich the flange Rf. Next, as shown in FIG. 12, both flanges Lf,
Rf is bent about 45 degrees and knocked down. Then, as shown in FIG. 13, both flanges Lf and Rf are further
Bend about 5 degrees and beat completely. Thus, a bent vent pipe V as shown in FIG. 14 is completed. Then, when the actuator 14 is contracted after processing and the second metal core Y is retracted in the horizontal direction so as to be separated from the first metal core X, the curved vent pipe V can be taken out.

In this case, during the movement of the driven arm 20, in the torque guide 50, two tops 53,
The contact of the driven arm 20 with the driven arm 53 suppresses the torsion of the driven arm 20.
Since the guides 2 and 66 are guided by engaging with the rails 61a and 61b and the guides 65a and 65b, the driven arm 20 moves accurately along the work dividing surface.

Therefore, according to the above-described manufacturing method, the flanges Lf, Rf integrally provided on the mating surfaces of the workpieces L, R are provided.
Are welded together, so that the welding operation is not required, and the automation of the production of the bent vent pipe V having the straight portions Sa and Sb at both ends can be advanced.
In addition, since the workpieces L and R are not burnt unlike welding, the appearance can be finely finished. Further, since the metal cores X and Y can be brought into good contact with the inner surface of the inner and outer peripheral walls of the bent portion of the bent pipe without causing interference with the bent vent pipe V, the metal cores X and Y can be reliably supported.
f and Rf can be automatically wound. Further, the rollers 71a, 71b and 72a, 72b
The manufacturing apparatus suitable for the above-mentioned manufacturing method could be provided by utilizing the winding mechanism using the.

In this embodiment, not only the bent vent pipe V shown in each figure but also another bent vent pipe V having a different radius and a different pipe diameter can be manufactured and processed. That is, the driven arm 20 has the roller 71
A plurality of mounting holes for mounting the a, 71b and 72a, 72b together with the pedestal are formed at a certain distance in the longitudinal direction, and a pedestal with a roller is mounted at a necessary portion according to the size of the curved vent pipe. I have. In addition, guide slot 1
5 is formed by bolting a plate material having the empty space to the frame plate 10, and replacing the plate material in accordance with the size of the curved vent pipe to form the position and shape of the guide elongated hole 15. Is changing.

FIG. 15 shows a modification. This modified example is a processing auxiliary device used for manufacturing a curved vent pipe V ′ having both ends slightly narrowed. In the above embodiment, in the case of the first metal core X, the third member 122c is fixedly attached to the first member 122a and the second member 122b. However, in the first metal core X 'of this modified example, the third member 122c is used. The end of 'c is supported on the first member 122a and the second member 122b by a pin 122'd, and the tip of the third member 122'c is
By swinging around 2'd, the third member 122 '
c is accommodated between the first member 122a and the second member 122b, or is configured to protrude from between the first member 122a and the second member 122b. A stepped portion corresponding to the narrowed portion of the curved vent pipe V 'is formed on the inner peripheral end surface of the moving support portion 123 and the outer peripheral end surface of the third member 122'c. This configuration is the second
The same applies to the cored bar Y ', and the third member 132'c
Is supported on the first member 132a and the second member 132b by the pin 132'd, and the tip of the third member 132'c swings around the pin 132'd, so that the third member 132'c Is housed between the first member 132a and the second member 132b, or protrudes from between the first member 132a and the second member 132b. A stepped portion corresponding to the narrowed portion of the vent pipe V 'is formed on the inner peripheral end surface of the moving support portion 133 and the outer peripheral end surface of the third member 132'c.

In the case of the above modification, in the state where the second metal core Y 'is retracted, the moving support portions 123 and 133 and the third member 12 are provided in both the first metal core X' and the second metal core Y '.
Both 2 ′ and 132 ′ are in a housed state, so that the first metal core X ′ and the second metal core Y ′ do not interfere with the curved vent pipe V ′. Next, the second mandrel Y 'is replaced with the first mandrel X'
And the push-out pin 125 functions to squeeze the moving support portions 123 and 133 and the third members 122 ′ and 132 ′. Fully supported. And roller 7
When the second cored bar Y ′ starts to be retracted after the completion of the winding process by 1a, 71b and 72a, 72b, the push-out pin 125 stops functioning and the moving support portion 123,
When the 133 and the third members 122 'and 132' are in the housed state and the second core Y 'is completely retracted, the curved vent pipe V can be taken out. In this case, the driven arm 20
The positions of the rollers 71a, 71b and 72a, 72b are set so as to match the narrowed portion of the end of the vent pipe. And rollers 71a, 71b and 72a,
72b is urged by a spring in a direction approaching the metal cores X 'and Y', so that when machining the inner enlarged diameter portion from the stepped portion, it rides up against the urging force of the spring to machine. It has become.

Therefore, also in the above-mentioned modified example, the metal cores X 'and Y' can be satisfactorily brought into contact with the inner surface of the inner and outer peripheral walls of the bent portion of the bent pipe without interference with the vent pipe V ', and can be reliably supported. In addition, the same operation and effect as those of the above embodiment can be obtained.

In the above embodiment and the modified example, the first metal cores X and X 'are fixed to the frame plate 10 and the second metal cores Y and Y' are horizontally moved with respect to the frame plate 10 by the actuator 14. The first core metal X,
X ′ is also connected to the frame plate 10 via an actuator such as an air cylinder that reciprocates in the vertical direction,
It may be reciprocable in the vertical direction.

In the above embodiment, the tracking guide 60 is connected to two pairs of rails 61a, 61b and 65a, 6b.
5b and the two engaging portions 62 and 66, but may be constituted only by a pair of rails and one engaging portion. Further, the shape of the tracking guide may be any shape as long as it can temporarily supplement the guiding function of the guide elongated hole 15, and therefore, is configured only by the pair of rails 61 a and 61 b and the one engaging portion 62 shown in the above embodiment. May be. Further, as the tracking guide 60, rails 61a, 61b and 65 are used.
Instead of a and 65b, a groove may be formed in the frame plate 10 and an engaging portion may be fitted into this groove. The engaging portion may be one having a roller supported at the tip. Further, in the above embodiment,
The guide slot 15 is formed along the work division surface, and the pin 2
1 is connected to the driven arm 20, and the elongated hole 33 in which the pin 21 is fitted is formed in the drive arm 30, but the guide elongated hole is formed in an arc around the rotation center of the drive arm, and the pin is replaced with the driven arm. An elongated hole connected to the drive arm and into which the pin fits may be formed in the driven arm instead of the drive arm. In this case, the tracking guide 60 needs to have a function of guiding at a right angle,
For example, only the rails 61a and 61b and one engagement portion 62 shown in the above embodiment, or only the rails 65a and 65b and one engagement portion 66 may be used.

[0028]

As described above, the method for manufacturing a bent vent pipe according to the first aspect of the present invention ties a workpiece having a shape obtained by dividing the bent vent pipe into two parts by inner and outer peripheral walls and integrally forming a flange at the divided part. The metal cores are allowed to penetrate from both ends, and the tips are connected in a separable manner to make contact with the inner surface of the processing location. In both the inner peripheral wall flange and the outer peripheral wall flange, the flanges are continuously rolled sideways from the ends thereof and tightened, so that the work can be reliably supported without causing interference with the work. Not only eliminates the need for welding work, but also automates the manufacture of curved vent pipes with straight sections at both ends,
Production efficiency can be improved, costs can be reduced, and the appearance can be beautifully finished.

Further, the manufacturing apparatus according to claim 2 is provided with a pair of metal cores which respectively enter from both ends of the vent pipe and are connected so that their tips can be separated from each other. The fixed support portion to be in contact is formed so as not to interfere with the vent pipe when the core metal enters, and a movable support portion that protrudes from the core metal so as to be able to return from the core metal at the time of connection and abuts on the remaining portion of the inner surface of the processing portion is provided. And a guide slot having a predetermined width extending along the work dividing surface is provided in the frame plate, and a driven arm is arranged on the work side of the frame plate. A pin which is slidably fitted to the guide long hole is connected to the arm, and a drive arm which has a long hole into which the pin is fitted on a side opposite to the work of the frame plate and is rotated by a driving means is supported. And the above frame A guide portion for guiding the movement of the driven arm is provided on the plate, and a roller that presses the work flange is supported on the driven arm, so that the work is securely supported and the work flange is tightened. As a result, a manufacturing apparatus suitable for automatically manufacturing a curved vent pipe can be proposed.

Further, the manufacturing apparatus according to claim 3 is based on claim 2.
In the manufacturing apparatus described above, the guide elongated hole is formed in an arc shape around the rotation center of the drive arm, the pin is connected to the drive arm instead of the driven arm, and the elongated hole into which the pin is inserted is driven instead of the drive arm. Since it is formed on the arm,
A modification of claim 2 could be shown.

[Brief description of the drawings]

FIG. 1 is a left side view of a manufacturing apparatus according to an embodiment, with a periphery of a roller removed.

FIG. 2 is a right side view of the manufacturing apparatus according to the embodiment;

FIG. 3 is a partially longitudinal front view,

FIG. 4 is a left side view of a main part, similarly showing a tracking guide;

FIG. 5 is a left side view of an essential part showing a state where a part of the metal core is also removed;

FIG. 6 is a view taken in the direction of arrow A in FIG. 5,

FIG. 7 is a left side view of a longitudinal section of a main part showing a periphery of a metal core when a work is set;

FIG. 8 is a diagram corresponding to FIG. 7 when the core metal is connected,

FIG. 9 is a diagram corresponding to FIG.

FIG. 10 is a perspective view of a work at the time of setting,

FIG. 11 is an explanatory diagram showing a winding process by a first roller,

FIG. 12 is an explanatory view showing a winding process by a second roller,

FIG. 13 is an explanatory view showing a winding process by a third roller,

FIG. 14 is a perspective view of the work at the time of completion,

FIG. 15 is a diagram corresponding to FIG. 5 in a modification,

FIG. 16 is a perspective view showing a conventional bent vent pipe.

[Explanation of symbols]

 V Curved vent pipe Sa straight section Sb straight section L Work Lf Flange R Work Rf Flange 10 Frame plate X 1st metal core Y 2nd metal core 15 Guide slot 20 Followed arm 21 Pin 30 Drive arm 40 Drive means 50 Torque guide 60 Tracking guide 71a Roller 71b Roller 72a Roller 72b Roller X 'First core Y' Second core

Claims (3)

(57) [Claims] 1. A method for manufacturing a bent vent pipe having a straight portion at both ends, the method comprising the steps of: forming a curved bent pipe having a shape obtained by dividing the bent vent pipe into two parts by inner and outer peripheral walls and integrally forming a flange at the divided part. Hook, then insert the metal core from both ends of the work, connect the tips in a separable manner, and abut against the inner surface of the processing location, then protrude part of the metal core and touch the rest of the internal surface of the processing location A method for manufacturing a bent vent pipe, comprising: bringing a flange into contact with an inner peripheral wall and a flange of an outer peripheral wall; 2. A pair of metal cores each of which penetrates from both ends of a vent pipe and whose ends are separably connected to each other, and which has a fixed support portion which abuts on an inner surface of a processing portion at the time of connection.
It is formed so that it does not interfere with the vent pipe when the core metal enters, and at the same time, it has a movable support part that protrudes so that it can return from the core metal at the time of connection and abuts on the remaining part of the inner surface of the processing part, and is almost parallel to the work division surface An erect frame plate is provided, and a guide slot having a predetermined width is formed through the frame plate along a work dividing surface. A driven arm is disposed on the work side of the frame plate, and the guide slot is inserted into the driven arm. A pin which is slidably fitted to the frame plate is connected, and a driving arm which has a long hole into which the pin is fitted on the opposite side of the frame plate and which is rotated by driving means is pivotally supported. 2. The manufacturing apparatus according to claim 1, wherein a guide portion for guiding the movement of the driven arm is provided, and a roller for pressing a flange of a work is pivotally supported on the driven arm. 3. A manufacturing apparatus used in the method for manufacturing a bent vent pipe according to claim 2, wherein the guide elongated hole is formed in an arc shape around the rotation center of the drive arm, and the pin is provided on the drive arm instead of the driven arm. A manufacturing apparatus for use in a method for manufacturing a curved vent pipe in which a long hole to be connected and into which a pin is inserted is formed in a driven arm instead of a driving arm.