Bending device

Abstract

The bending device is adapted to bending of a longitudinal workpiece. The device comprises a bending die that has an outer shape corresponding to the bending shape, a clamping die that clamps the workpiece with the bending die, and a rotation mechanism that rotates the bending die and the clamping die to a predetermined bending direction while the workpiece is being clamped between the bending die and the clamping die. The rotation mechanism is provided with a selection mechanism that allows switching between a first rotation mode in which the bending die and the clamping die are rotated in a body and a second rotation mode in which one of the bending die and the clamping die is rotated independently of the other die.

Description

FIELD OF THE INVENTION

This invention relates to a bending device, which bends a longitudinal workpiece to both left and right sides.

BACKGROUND OF THE INVENTION

As disclosed in the Unexamined Japanese Patent Publication No. 62-267024, a conventionally known bending device, which bends a longitudinal workpiece to both left and right sides, is provided with a right bending jig, including a pressure die, a bending die, and a clamping die, to be used in bending the workpiece to a right side, and a left bending jig, including a pressure die, a bending die, and a clamping die, to be used in bending the workpiece to a left side.

When bending the workpiece to the right side, the right bending jig is moved to the position corresponding to the center of right bending of the workpiece so as to execute right bending. When bending the workpiece to the left side, the left bending jig is moved to the position corresponding to the center of left bending of the workpiece so as to execute left bending. Thus, bending to both the left and right sides is achieved.

SUMMARY OF THE INVENTION

However, in a conventional bending device as above, the right and left bending jigs are moved to the positions corresponding to the respective centers for bending depending on the bending direction. Therefore, large and heavy left and right jigs provided with the respective bending and clamping dies have to be moved in its entirety, thus making the device complex and huge.

One object of the present invention is to provide a bending device which is simple in structure and capable of bending a longitudinal workpiece to both the left and right sides.

To attain this and other objects, a bending device of the present invention comprises: a bending die that has an outer shape corresponding to a bending shape, a clamping die that clamps a workpiece with the bending die, and a rotation mechanism that rotates the bending die and the clamping die to a predetermined bending direction while the workpiece is being clamped between the bending die and the clamping die, so as to bend the workpiece.

The rotation mechanism includes a selection mechanism that allows switching between a first rotation mode in which the bending die and the clamping die are rotated in a body and a second rotation mode in which one of the bending die and the clamping die is rotated independently of the other die.

According to the present invention, at least one of the bending die and the clamping die is rotated by means of the selection mechanism. Therefore, it is possible to shift the respective positions of the bending die and the clamping die either to the positions for bending the workpiece to a right side or to the positions for bending the workpiece to a left side.

Consequently, the present invention enables bending of the workpiece to both the left and right sides, using a single pair of the bending die and the clamping die. Thus, the configuration of the device can be simple.

In the present invention, the rotation mechanism may set the relative position between the bending die and the clamping die either to a first relative position which is an initial position when bending the workpiece to the right side and to a second relative position which is an initial position when bending the workpiece to the left side, by rotating at least one of the bending die and the clamping die by means of the selection mechanism.

In this manner, by feeding the workpiece between the bending die and the clamping die that are either in the first relative position or in the second relative position, bending of the workpiece to the right side or to the left side can be desirably executed.

The rotation mechanism may comprise a rotational force applicator that transmits a rotational force to at least one of the bending die and the clamping die.

In the above case, the selection mechanism may transmit the rotational force from the rotational force applicator to both the bending die and the clamping die in the first rotation mode, while the selection mechanism may transmit the rotational force from the rotational force applicator to either of the bending die and the clamping die in the second rotation mode.

The bending die may have a linear section in its outer shape. In such a case, it is preferable that the clamping die may be designed to clamp the workpiece with the linear section of the bending die.

Then, compared with the case in which the workpiece is clamped between a curved section of the bending die and the clamping die, for example, it is difficult for positional deviation of the workpiece to occur between the bending die and the clamping die upon bending.

The bending die may be provided with a first linear section in part of its outer shape facing the clamping die when the relative position between the bending die and the clamping die is in the first relative position, and with a second linear section in part of its outer shape facing the clamping die when the relative position between the bending die and the clamping die is in the second relative position.

In this case, the clamping die clamps the workpiece with the first linear section of the bending die when the workpiece is being bent to the right side, while the clamping die clamps the workpiece with the second linear section of the bending die when the workpiece is being bent to the left side.

In the above case as well, occurrence of positional deviation of the workpiece between the bending die and the clamping die upon bending is relatively made difficult.

In the present invention, the clamping die may be a single die, or may be composed of plural number of clamping dies.

For example, the clamping die may include a clamping die for right bend that clamps the workpiece with the bending die when bending the workpiece to the right side, and a clamping die for left bend that clamps the workpiece with the bending die when bending the workpiece to the left side.

Furthermore, in case that the relative position between the bending die and the clamping die can be in the first relative position and the second relative position, the clamping dies for right bend and left bend may be designed as follows.

That is, the clamping die for right bend may clamp the workpiece with the first linear section of the bending die when bending the workpiece to the right side. Also, the clamping die for left bend may clamp the workpiece with the second linear section of the bending die when bending the workpiece to the left side.

In this manner, even in the case of clamping the workpiece with either one of the clamping die for right bend and the clamping die for left bend, occurrence of positional deviation of the workpiece being bent between the bending die and the clamping die (clamping die for right bend or left bend) is relatively made difficult.

When the clamping dies for right bend and left bend are provided, it is preferable that the clamping dies for right bend and left bend are arranged in such a manner that the moving directions of the respective clamping dies when clamping the workpiece are nearly parallel to each other.

It is noted that the clamping dies for right bend and left bend may also be arranged in such a manner that the moving directions of the respective clamping dies when clamping the workpiece are not nearly parallel.

In the present invention, the bending die may include in its outer shape a plurality of bending die contact portions which correspond to a plurality of bending shapes of the workpiece, and the clamping die may include in its outer shape a plurality of clamping die contact portions which correspond to a plurality of bending shapes of the workpiece.

In the above case, the bending device may be constituted such that, when the workpiece is clamped between the bending die and the clamping die to be bent, the workpiece is clamped between one of the bending die contact portions and one of the clamping die contact portions respectively selected in accordance with the bending shape of the workpiece.

In this manner, plural patterns of bending can be applied to the workpiece.

When the clamping dies for right bend and left bend are provided, the following constitution may be adopted.

That is, while the bending die has in its outer shape a plurality of bending die contact portions which correspond to a plurality of bending shapes of the workpiece, the clamping die for right bend may have in its outer shape a plurality of clamping die contact portions for right bend which correspond to a plurality of bending shapes of the workpiece, and the clamping die for left bend may have in its outer shape a plurality of clamping die contact portions for left bend which correspond to a plurality of bending shapes of the workpiece.

In the above case, it is preferable that the bending device is constituted such that, when the workpiece is clamped between the bending die and the clamping die for right bend to be bent to the right side, the workpiece is clamped between one of the bending die contact portions and one of the clamping die contact portions for right bend respectively selected in accordance with the bending shape of the workpiece.

Also, it is preferable that the bending device is constituted such that, when the workpiece its clamped between the bending die and the clamping die for left bend to be bent to the left side, the workpiece is clamped between one of the bending die contact portions and one of the clamping die contact portions for left bend respectively selected in accordance with the bending shape of the workpiece.

In such a manner as well, plural patterns of bending can be applied to the workpiece.

Furthermore, in case that the clamping dies for right bend and left bend are provided, the bending device may be constituted as follows.

That is, when bending the workpiece to the right side, the clamping die for right bend is moved toward the bending die so that the workpiece is clamped between the bending die and the clamping die for right bend. When bending the workpiece to the left side, the clamping die for left bend is moved toward the bending die so that the workpiece is clamped between the bending die and the clamping die for left bend.

Conversely, when bending the workpiece to the right side, the bending die may be moved toward the clamping die for right bend so that the workpiece is clamped between the bending die and the clamping die for right bend. When bending the workpiece to the left side, the bending die may be moved toward the clamping die for left bend so that the workpiece is clamped between the bending die and the clamping die for left bend.

In order to perform appropriate bending of the workpiece to both the left and right sides, the bending device of the present invention may be constituted as below.

The bending device of the present invention may comprise a right pressure die that receives a bending reaction force generated when bending the workpiece to the right side, and a left pressure die that receives a bending reaction force generated when bending the workpiece to the left side.

In this case, the right pressure die and the left pressure die may be disposed on both sides of the bending die.

When the bending die includes a plurality of bending die contact portions and the clamping die includes a plurality of clamping die contact portions, the right and left pressure dies may be designed as below.

The right pressure die may include a plurality of right pressure die contact portions corresponding to the shape of the workpiece, and the left pressure die may include a plurality of left pressure die contact portions corresponding to the shape of the workpiece.

In the above case, when the workpiece is clamped between one of the bending die contact portions and one of the clamping die contact portions respectively selected in accordance with the bending shape of the workpiece to the right side, it is preferable that one of the plurality of right pressure die contact portions is in contact with the workpiece to receive the bending reaction force. Similarly, when the workpiece is clamped between one of the bending die contact portions and one of the clamping die contact portions respectively selected in accordance with the bending shape of the workpiece to the left side, it is preferable that one of the plurality of left pressure die contact portions is in contact with the workpiece to receive the bending reaction force.

The bending device of the present invention may comprise a chuck that grips the workpiece, and a feed mechanism that moves the chuck in a longitudinal direction of the workpiece and two directions which are directions orthogonal to the longitudinal direction so as to feed the workpiece between the bending die and the clamping die to be clamped therebetween.

In the above manner, proper feeding of the workpiece is possible to the position necessary for bending with the bending die and the clamping die.

BRIEF DESCRIPTION OF THE DRAWING FIGURES

The invention will now be described, by way of example, with reference to the accompanying drawings, in which:

FIG. 1 is an plan view showing a schematic constitution of a bending device according to an embodiment of the present invention, in which a state is illustrated when bending a pipe as a workpiece to the right side;

FIG. 2 is a partially enlarged cross sectional view, taken along the line II-II in FIG. 1;

FIG. 3 is a plan view showing a schematic constitution of the bending device of the present embodiment, in which a state is illustrated when bending the pipe to the left side;

FIG. 4 is a partially enlarged cross sectional view, taken along the line IV-IV in FIG. 3;

FIG. 5 is a partial side view of the bending device of the embodiment, viewed from the V direction in FIG. 2;

FIG. 6 is a partially enlarged cross sectional view, taken along the line VI-VI in FIG. 1;

FIG. 7 is a block diagram showing an electric constitution of the bending device of the embodiment;

FIG. 8 is a flowchart showing an example of a control process executed in an electronic control circuit of the bending device of the embodiment;

FIGS. 9A and 9B are explanatory views which illustrate a process when bending the pipe to the right side; and

FIGS. 10A and 10B are explanatory views which illustrate a process when bending the pipe to the left side.

BEST MODE TO CARRY OUT THE INVENTION

As shown in FIGS. 1 to 4, a bending device 100 of the present embodiment comprises a bending die 6, a clamping die 50, a right pressure die 56, a left pressure die 58, and a chuck 80. The clamping die 50 includes a clamping die 52 for right bend and a clamping die 54 for left bend.

As later explained, the bending device 100 bends a workpiece 1, such as a longitudinal pipe, to the right side (i.e., a direction of arrow R in FIG. 9A), by cooperation between the bending die 6, the clamping die 52 for right bend, and the right pressure die 56. Also, the bending device 100 bends the workpiece 1 to the left side (i.e., a direction of arrow L in FIG. 10A), by cooperation between the bending die 6, the claming die 54 for left bend, and the left pressure die 58.

The bending die 6 is provided in its outer shape with a plurality of bending grooves 2a, 2b (see FIGS. 2 and 4) in tiers, as a plurality of bending die contact portions corresponding to a plurality of bending shapes of the workpiece 1. The bending grooves 2a, 2b are respectively formed into a shape corresponding to the outer shape of the workpiece 1. In the present embodiment, the bonding die 6 is provided with a large diameter portion 4a having the bending groove 2a in its outer shape, and a small diameter portion 4b having the bending groove 2b in its outer shape. The large diameter portion 4a and the small diameter portion 4b are arranged in a stack in a vertical direction (i.e., a direction of arrow Z in FIGS. 2 and 4) orthogonal to the longitudinal direction (i.e., a direction of arrow X in FIGS. 1 and 3) of the workpiece 1.

The bending groove 2a of the large diameter portion 4a is formed into a continuous groove including a semi-arc bending section 4a1, a first linear section 4a2, and a second linear section 4a3. The bending groove 2b of the small diameter portion 4b is formed into a continuous groove including a semi-arc bending section 4b1, a first linear section 4b2, and a second linear section 4b3. The large diameter portion 4a and the small diameter portion 4b are formed to be symmetrical in a lateral direction (i.e., a direction of arrow Y in FIGS. 1 and 3) of the workpiece 1.

A bending shaft 8 extends in the vertical direction (Z direction) orthogonal to the longitudinal direction of the workpiece 1 and is rotatably supported by a device body 10. The bending die 6 is fixed on an end face of the bending shaft 8. The bending shaft 8 functions as a rotation axis of the bending die 6.

As shown in FIGS. 2 and 4, a bending arm 12 is rotatably supported on the bending shaft 8. A pair of left and right clamping tables 14, 16 are swingably attached to the bending arm 12 via link mechanisms 18, 26. On the right clamping table 14, the clamping die 52 for right bend is provided to face the bending die 6. Also, on the left clamping table 16, the clamping die 54 for left bend is provided to face the bending die 6.

As shown in FIG. 2, the link mechanism 18 includes a drive link 19 and a driven link 24. The link mechanism 18 supports the right clamping table 14 so as to enable the right clamping table 14 to move close to or away from the bending die 6. The drive link 19 and the driven link 24 together form a parallel linkage.

Particularly, the drive link 19 includes a V-shaped link bar 20 and a hydraulic mechanism 21. One end 20a of the V-shaped link bar 20 is rotatably supported on the right clamping table 14, and the other end 20b of the V-shaped link bar 20 is rotatably supported on a tip portion 22a of a rod 22 of the hydraulic mechanism 21. The hydraulic mechanism 21 is provided with the rod 22 and a hydraulic cylinder 23. The hydraulic cylinder 23 is supported to the bending arm 12 so as to freely rotate on a rotation axis 23a. The driven link 24 includes a linear link bar 25. One end 25a of the link bar 25 is rotatably supported on the right clamping table 14, and the other end 25b is rotatably supported to the bending arm 12.

In the link mechanism 18, the rod 22 is pulled into the hydraulic cylinder 23 by the control of oil pressure applied to the hydraulic cylinder 23, so as to move the clamping die 52 for right bend close to the bending die 6. Also, the rod 22 is pulled out of the hydraulic cylinder 23 so as to move the clamping die 52 for right bend away from the bending die 6.

On the other hand, as shown in FIG. 4, the link mechanism 26 supporting the left clamping table 16 includes a drive link 27 having the function and structure corresponding to the drive link 19, and a driven link 28 having the function and structure corresponding to the driven link 24.

In the link mechanism 26, a rod 27b is pulled into a hydraulic cylinder 27a by the control of oil pressure applied to the hydraulic cylinder 27a which is a component of the drive link 27, so as to move the clamping die 54 for left bend close to the bending die 6. Also, the rod 27b is pulled out of the hydraulic cylinder 27a so as to move the clamping die 54 for left bend away from the bending die 6.

As shown in FIG. 2, the clamping die 52 for right bend possesses, in its outer shape portion facing the bending die 6, a plurality of bending grooves 52a, 52b in tiers as a plurality of clamping die contact portions for right bend corresponding to a plurality of bending shapes of the workpiece 1. The bending grooves 52a, 52b are linear grooves having the shape corresponding to the outer shape of the workpiece 1. The bending groove 52a faces the bending groove 2a of the bending die 6, and the bending groove 52b faces the bending groove 2b of the bending die 6.

As shown in FIG. 4, the clamping die 54 for left bend possesses, in its outer shape portion facing the bending die 6, a plurality of bending grooves 54a, 54b as a plurality of clamping die contact portions for left bend corresponding to a plurality of bending shapes of the workpiece 1. The bending grooves 54a, 54b are linear grooves having the shape corresponding to the outer shape of the workpiece 1. The bending groove 54a faces the bending groove 2a of the bending die 6, and the bending groove 54b faces the bending groove 2b of the bending die 6.

When the relative position between the bending die 6 and the clamping die 50 is in a first relative position which is an initial position when bending the workpiece 1 to the right side (see FIG. 1), the bending grooves 52a, 52b of the clamping die 52 for right bend respectively face the first linear sections 4a2, 4b2 in the bending grooves 2a, 2b of the bending die 6.

In this case, the rod 22 is pulled into the hydraulic cylinder 23, so that the workpiece 1 can be clamped between the bending die 6 and the clamping die 52 for right bend (see FIG. 1). Particularly, the workpiece 1 arranged in the first linear section 4a2 of the bending die 6 is clamped between the first linear section 4a2 of the bending die 6 and the bending groove 52a of the clamping die 52 for right bend (see FIG. 2). Or, the workpiece 1 arranged in the first linear section 4b2 of the bending die 6 is clamped between the first linear section 4b2 of the bending die 6 and the bending groove 52b of the clamping die 52 for right bend.

When the relative position between the bending die 6 and the clamping die 50 is in a second relative position which is an initial position when bending the workpiece 1 to the left side (see FIG. 3), the bending grooves 54a, 54b of the clamping die 54 for left bend respectively face the second linear sections 4a3, 4b3 in the bending grooves 2a, 2b of the bending die 6.

In this case, the rod 27b is pulled into the hydraulic cylinder 27a, so that the workpiece 1 can be clamped between the bending die 6 and the clamping die 54 for left bend (see FIG. 3). Particularly, the workpiece 1 arranged in the second linear section 4a3 of the bending die 6 is clamped between the second linear section 4a3 of the bending die 6 and the bending groove 54a of the clamping die 54 for left bend (see FIG. 4). Or, the workpiece 1 arranged in the second linear section 4b3 of the bending die 6 is clamped between the second linear section 4b3 of the bending die 6 and the bending groove 54b of the clamping die 54 for left bend.

In the present embodiment, the clamping die 52 for right bend and the clamping die 54 for left bend are arranged in such a manner that their moving directions when clamping the workpiece 1 is nearly parallel to each other.

As shown in FIGS. 2, 4 and 5, the bending shaft 8 is provided with a selection mechanism 30. The selection mechanism 30 allows switching between a first rotation mode in which the bending die 6 and the bending arm 12 (clamping die 50) are rotated in a body around the bending shaft 8 and a second rotation mode in which only the bending die 6 out of the bending die 6 and the bending arm 12 (clamping die 50) is rotated around the bending shaft 8.

The selection mechanism 30 includes a connection member 31, a clutch member 33, a drive shaft 36, a motor 38, a belt 40, and a solenoid 46.

The connection member 31 is attached to a lower section of the bending shaft 8. The connection member 31 is provided with a recess 32 formed on its bottom. The clutch member 33 is provided to face the connection member 31. The clutch member 33 possesses a projection 34 that is inserted into the recess 32. The clutch member 33 is slidably supported on the drive shaft 36 disposed coaxially to the bending shaft 8. The clutch member 33 can be slid in axial and circumferential directions of the drive shaft 36.

The upper end of the drive shaft 36 is inserted and fixed to the connection member 31. The bending shaft 8 and the drive shaft 36 are connected so as to rotate in a body. The drive shaft 36 is rotatably supported to the device body 10. The drive shaft 36 is rotationally driven via the belt 40 by the motor 38 as a rotational force applicator attached to the device body 10.

A circular groove 42 is formed around the outer periphery of the clutch member 33. A cam follower 45 attached to a tip end of a lever 44 swingably supported to the device body 10 is fitted in the circular groove 42. A rod 46a of the solenoid 46 attached to the device body 10 is connected to the other end of the lever 44. The clutch member 33 is slid in the axial direction of the drive shaft 36 by the drive of the solenoid 46, so as to enable selection between connection and separation of the recess 32 and the projection 34.

As shown in FIGS. 2 and 4, the clutch member 33 has a portion 33a that projects in a direction away from the drive shaft 36 along the bending arm 12. A drive pin 48 provided upright on the bending arm 12 is engaged with the portion 33a.

Accordingly, when the clutch member 33 is rotated with the drive shaft 36, rotation of the drive shaft 36 is transmitted to the bending arm 12 via the clutch member 33 and the drive pin 48.

In other words, when the motor 38 is driven under the state that the recess 32 and the projection 34 are engaged, a rotational force of the motor 38 is transmitted to both the bending die 6 and the arm 12 (clamping die 50) (i.e., first rotation mode). At this point, the bending die 6 and the clamping die 50 are rotated in a body around the bending shaft 8.

On the other hand, when the motor 38 is driven under the state that the solenoid 46 is driven and the clutch member 33 is slid in the axial direction (downward) of the drive shaft 36 via the cam follower 45 so as to separate the projection 34 from the recess 32, the rotational force of the motor 38 is transmitted only to the bending die 6 out of the bending die 6 and the bending arm 12 (clamping die 50) (i.e., second rotation mode). At this point, although the bending die 6 is rotated around the bending shaft 8, the clamping shaft 50 is in a halt state.

As shown in FIGS. 1, 3, and 6, the left and right pressure dies 66, 58 are disposed on both left and right sides of the bending die 6 and the workpiece 1.

The right pressure die 56 is attached to a right pressure table 60, and receives a bending reaction force generated when bending the workpiece 1 to the right side by the simultaneous rotation of the bending die 6 and the clamping die 50 to the right side (see FIGS. 9A and 9B).

Particularly, the right pressure die 56 possesses, in its outer shape portion facing the workpiece 1 when the workpiece 1 is clamped between the bending die 6 and the clamping die 52 for right bend, a plurality of bending grooves 66a, 66b in tiers as a plurality of right pressure die contact portions corresponding to a plurality of bending shapes of the workpiece 1. The bending grooves 56a, 56b are linear grooves respectively having a shape corresponding to the outer shape of the workpiece 1. The bending groove 56a is pressed against the outer periphery of the workpiece 1 when the workpiece 1 is clamped between the first linear portion 4a2 of the bending die 6 and the bending groove 52a of the clamping die 52 for right bend (see FIG. 6). Also, the bending groove 56b is pressed against the outer periphery of the workpiece 1 when the workpiece 1 is clamped between the first linear portion 4b2 of the bending die 6 and the bending groove 52b of the clamping die 52 for right bend.

The left pressure die 58 is attached to a left pressure table 62, and receives a bending reaction force generated when bending the workpiece 1 to the left side by the simultaneous rotation of the bending die 6 and the clamping die 50 to the left (see FIGS. 10A and 10B).

Particularly, the left pressure die 58 possesses, in its outer shape portion facing the workpiece 1 when the workpiece 1 is clamped between the bending die 6 and the clamping die 54 for left bend, a plurality of bending grooves 58a, 58b in tiers as a plurality of left pressure die contact portions corresponding to a plurality of bending shapes of the workpiece 1. The bending grooves 58a, 58b are linear grooves respectively having a shape corresponding to the outer shape of the workpiece 1. The bending groove 68a is pressed against the outer periphery of the workpiece 1 when the workpiece 1 is clamped between the second linear portion 4a3 of the bending die 6 and the bending groove 54a of the clamping die 54 for left bend. Also, the bending groove 58b is pressed against the outer periphery of the workpiece 1 when the workpiece 1 is clamped between the second linear portion 4b3 of the bending die 6 and the bending groove 54b of the clamping die 54 for left bend.

The left and right pressure tables 60, 62 are movably supported to the device body 10 via respective link mechanisms 64, 72.

As shown in FIG. 6, the link mechanism 64 includes a drive link 65 and a driven link 70. The link mechanism 64 supports the right pressure table 60 so as to enable the right pressure die 56 on the right pressure table 60 to move close to or away from the workpiece 1. The drive link 65 and the driven link 70 together form a parallel linkage.

Particularly, the drive link 65 includes a V-shaped link bar 66 and a hydraulic mechanism 67. One end 66a of the V-shaped link bar 66 is rotatably supported on the right pressure table 60, and the other end 66b of the V-shaped link bar 66 is rotatably supported on a tip portion 68a of a rod 68 of the hydraulic mechanism 67. The hydraulic mechanism 67 is provided with the rod 68 and a hydraulic cylinder 69. The hydraulic cylinder 69 is supported to a portion 11a of the device body 10 so as to freely rotate on a rotation axis 69a. The driven link 70 includes a linear link bar 71. One end 71a of the link bar 71 is rotatably supported on the right pressure table 60, and the other end 71b is rotatably supported to the portion 11a of the device body 10.

In the link mechanism 64, when bending the workpiece 1 to the right side, the rod 68 is pulled into the hydraulic cylinder 69 by the control of oil pressure applied to the hydraulic cylinder 69, so as to move the right pressure die 56 close to the workpiece 1. Also, the rod 68 is pulled out of the hydraulic cylinder 69 so as to move the right pressure die 56 away from the workpiece 1.

On the other hand, as shown in FIG. 6, the link mechanism 72 supporting the left pressure table 62 includes a drive link 73 having the function and structure corresponding to the drive link 65, and a driven link 74 having the function and structure corresponding to the driven link 70.

In the link mechanism 72, when bending the workpiece 1 to the left side, a rod 73b is pulled into a hydraulic cylinder 73a by the control of oil pressure applied to the hydraulic cylinder 73a which is a component of the drive link 73, 80 as to move the left pressure die 58 close to the workpiece 1. Also, the rod 73b is pulled out of the hydraulic cylinder 73a so as to move the left pressure die 58 away from the workpiece 1.

As shown in FIGS. 1 and 3, a rear end of the workpiece 1 is gripped by the chuck 80. The chuck 80 gripping the workpiece 1 is retained in a feed mechanism 82 provided in the device body 10 so that the chuck 80 can be moved in three directions that is, the longitudinal direction of the workpiece 1 (a direction of arrow X in FIGS. 1 and 3), the lateral direction orthogonal to the longitudinal direction (a direction of arrow Y in FIGS. 1 and 3), and the vertical direction (a direction of arrow Z in FIGS. 2, 4 and 6).

The feed mechanism 82 includes rails 84, a feed table 86, and a move table 90. The rails 84 are a pair of rails laid in the device body 10 parallel to the longitudinal direction of the workpiece 1. The feed table 86 can be moved in the longitudinal direction (X direction) along the rails 84 by the drive of a motor 116a (see FIG. 7). A pair of rails 88 extending in the lateral direction (Y direction) are provided on the feed table 86. The move table 90 can be moved in the lateral direction (Y direction) along the rails 88 by the drive of a motor 116b (see FIG. 7). As shown in FIG. 6, a guide member 92 extending in the vertical direction (Z direction) is provided upright on the move table 90. The chuck 80 can be moved in the vertical direction (Z direction) along the guide member 92 by the drive of a motor 116c (see FIG. 7).

Now, the electric system of the bending device of the present embodiment is described by way of a block diagram shown in FIG. 7. The present device is driven and controlled by an electronic control circuit 101 to process the workpiece 1. The electronic circuit 101 mainly includes an arithmetic logic circuit including known CPU 102, ROM 104, RAM 106, and so on. The arithmetic logic circuit is connected to an external motor via an input/output port 10880 as to input/output signal.

The CPU 102 inputs signal from respective position sensors 110a, 110b, 110c, 110d, 110e, 110f, hog, and 110h via the input/output port 108.

Among the aforesaid position sensors, the position sensor 110a includes an encoder that detects the rotation angle position of the drive axis 36 (and consequently, the bending die 6 and the clamping die 50). The position sensor 110b includes a limit switch that detects a forward end and a rearward end of the clamping die 62 for right bend that is moved close to and away from the bending die 6 by the operation of the link mechanism 18. The position sensor 110c includes a limit switch that detects a forward end and a rearward end of the clamping die 54 for left bend that is moved close to and away from the bending die 6 by the operation of the link mechanism 26. The position sensor 110d includes a limit switch that detects a forward end and a rearward end of the right pressure die 56 that is moved close to and away from the workpiece 1 by the operation of the link mechanism 64 at the time of bending the workpiece 1 to the right side. The position sensor 110e includes a limit switch that detects a forward end and a rearward end of the left pressure die 58 that is moved close to and away from the workpiece 1 by the operation of the link mechanism 72 at the time of bending the workpiece 1 to the left side. The position sensor 110f includes an encoder that detects rotation of the motor 116a to detect the position of the feed table 86 (chuck 80) in the longitudinal direction (X direction). The position sensor 110g includes an encoder that detects rotation of the motor 116b to detect the position of the moving table 90 (chuck 80) in the lateral direction (Y direction). The position sensor 110h includes an encoder that detects rotation of the motor 116c to detect the position of the chuck 80 in the vertical direction (Z direction).

The CPU 102 outputs control signal based on data and signal from these sensors and the data in the ROM 104 and RAM 106, via the input/output port 108 and driving circuits 112a, 112b, 112c, 112d, 112e, 112f, 112g, 112h, and 112i, so as to control the respective drive systems of the bending device.

In FIG. 7, a servo valve 114a is a valve for controlling oil pressure applied to the hydraulic cylinder 23, and a servo valve 114b is a valve for controlling oil pressure applied to the hydraulic cylinder 27a. A servo valve 114c is a valve for controlling oil pressure applied to the hydraulic cylinder 69, and a servo valve 114d is a valve for controlling oil pressure applied to the hydraulic cylinder 73a.

Hereinafter, a process performed in the electronic control circuit 101 based on the program data stored in the ROM 104, when the workpiece 1 is bent in the bending device of the present embodiment, is described by way of a flowchart illustrated in FIG. 8 and explanatory views shown in FIGS. 9A, 9B, 10A and 10B.

Firstly, the rear end of the workpiece 1 is gripped by the chuck 80 (Step 200).

Then, the bending die 6 and the clamping die 50 are set at their original positions in accordance with the bending direction of bending to be applied to the workpiece 1 (Step 210).

Particularly, when bending the workpiece 1 to the right side, the relative position between the bending die 6 and the clamping die 50 is set to the first relative position in which the bending grooves 52a, 52b of the clamping die 52 for right bend face the first linear sections 4a2, 4b2, respectively (see FIG. 1). At this point, the rod 22 is pulled out of the hydraulic cylinder 23 so that the clamping die 52 for right bend is spaced apart from the bending die 6.

When bending the workpiece 1 to the left side, the relative position between the bending die 6 and the clamping die 50 is set to the second relative position in which the bending grooves 54a, 54b of the clamping die 54 for left bend face the second linear sections 4a3, 4b3, respectively (see FIG. 3). At this point, the rod 27b is pulled out of the hydraulic cylinder 27a so that the clamping die 54 for left bend is spaced apart from the bending die 6.

In Step 210, the first rotation mode or the second rotation mode is achieved, where appropriate, depending on the control signal outputted to the solenoid 46 via the drive circuit 112b. By the control signal outputted to the motor 38 via the drive circuit 112a, at least one of the bending die 6 and the clamping die 50 is rotated around the bending shaft 8, so as to achieve the aforementioned first relative position or second relative position. Achievement of the first relative position or second relative position is detected by the position sensor 110a.

Next, by the control signal outputted to the motors 116a, 116b, and 1.16c via the drive circuits 112g, 112h, and 112i, the chuck 80 is moved so that the workpiece 1 is fed to the position between the bending die 6 and the clamping die 50 in accordance with the bending direction of the workpiece 1 (Step 220).

Particularly, when bending the workpiece 1 to the right side, the workpiece 1 is arranged in the first linear section 4a2 or 4b2 of the bending die 6 in accordance with the bending shape of the workpiece 1. When bending the workpiece 1 to the left, the workpiece 1 is arranged in the second linear section 4a3 or 4b3 of the bending die 6 in accordance with the bending shape of the workpiece 1.

In this state, the feed table 86 is moved toward the bending die 6 along the rails 84 by the drive of the motor 116a.

The moving position of the feed table 86 (workpiece 1) in the longitudinal direction (X direction) is detected by the position sensor 110f. The feed table 86 continues to be moved until the workpiece 1 reaches the initial bending position with respect to the bending die 6 and the clamping die 50 (Step 230: NO).

When it is detected that the workpiece 1 has reached the initial bending position based on signal from the position sensor 110f (Step 230: YES), the move of the workpiece 1 by the feed mechanism 8 is stopped (Step 240).

Next, drive signal is outputted to the servo valve 114a via the drive circuit 112c or drive signal is outputted to the servo valve 114b via the drive circuit 112d, so that the workpiece 1 is clamped between the bending die 6 and the claming die 50 (Step 250).

Particularly, when bending the workpiece 1 to the right side, the rod 22 is pulled into the hydraulic cylinder 23, so that the workpiece 1 is clamped between the first linear section 4a2 of the bending die 6 and the bending groove 52a of the clamping die 52 for right bend, or between the first liner section 4b2 of the bending die 6 and the bending groove 52b of the clamping die 52 for right bend.

When bending the workpiece 1 to the left side, the rod 27b is pulled into the hydraulic cylinder 27a so that the workpiece 1 is clamped between the second linear section 4a3 of the bending die 6 and the bending groove 54a of the clamping die 54 for left bend, or between the second liner section 4b3 of the bending die 6 and the bending groove 54b of the clamping die 54 for left bend.

In Step 250, after the workpiece 1 is clamped between the bending die 6 and the clamping die 50 as above, the right pressure die 56 or the left pressure die 58 is pressed against the workpiece 1.

Particularly, when bending the workpiece 1 to the right side, drive signal is outputted to the servo valve 114c via the drive circuit 112e. Consequently, the rod 68 is pulled into the hydraulic cylinder 69, and the bending groove 56a or 56b of the right pressure die 56 is pressed against the outer periphery of the workpiece 1 (see FIGS. 1, 6 and 9A).

When bending the workpiece 1 to the left side, drive signal is outputted to the servo valve 114d via the drive circuit 112f. Consequently, the rod 73b is pulled into the hydraulic cylinder 73a, and the bending groove 58a or 58b of the left pressure die 58 is pressed against the outer periphery of the workpiece 1 (see FIGS. 3 and 10A).

Next, whether the bending to be executed to the workpiece 1 through Steps 280 to 300 of the current flow (Steps 210 to 320 now in progress) is the final bending to the workpiece 1 is determined based on the data inputted from the outside to the CPU 102 (Step 260).

When it is positively determined in Step 260, that is, if there is no more bending to be executed to the other part of the workpiece 1 (Step 260: YES), the process moves to Step 270.

In Step 270, the gripping force to the workpiece 1 by the chuck 80 is loosened so as to release the workpiece 1 from the chuck 80 (Step 270). Then, the process moves to Step 280.

On the other hand, when it is negatively determined in Step 260, that is, if there is another bending to be performed to the other part of the workpiece 1 (Step 260: NO), the process moves to Step 280.

In Step 280, the bending die 6 and the clamping die 50 are rotated in a body around the bending shaft 8, by control signal outputted to the motor 38 via the drive circuit 112a under the state that the first rotation mode is achieved by the control signal outputted to the solenoid 46 via the drive circuit 112b.

As a result, the workpiece 1 is put around the bending groove 2a or 2b of the bending die 6 to be bent to the right or left side. The bending reaction force at the time is received by the right pressure die 66 or the left pressure die 58.

The bending angle (rotation angle of the bending die 6 and the clamping die 60) at the time of bending is sequentially detected by the position sensor 110a. In the present embodiment, based on the detection value by the position sensor 11a, whether the bending angle has reached a predetermined angle is continuously determined during the bending (Step 290). While it is negatively determined in Step 290 (Step 290: NO), bending by the bending die 6 and the clamping die 50 is continued. When it is positively determined (Step 290: YES), rotation of the bending die 6 and the clamping die 50 is terminated to stop the bending (Step 300).

The aforementioned “predetermined angle” can be arbitrarily set to, e.g., approximately 180° and 90°. FIG. 9B shows the state in which the first bending has been completed (the state when Step 300 is completed), when the first bending direction of the workpiece 1 is right and the aforesaid “predetermined angle” is about 180°. In this case, the workpiece 1 is bent to form a U-shape.

Next, the clamping of the workpiece 1 is released (Step 810).

Particularly, when the bending to the right side of the workpiece 1 is complete in Step 300, drive signal is outputted via the drive circuit 112c to the servo valve 114a so as to pull the rod 22 out of the hydraulic cylinder 23. As a result, the clamping die 52 for right bend is separated from the bending die 6, the clamping of the workpiece 1 by the bending die 6 and the clamping die 52 for right bend is released. Also, at this point, drive signal is outputted via the drive circuit 112e to the servo valve 114c to pull the rod 68 out of the hydraulic cylinder 69. As a result, the right pressure die 56 is separated from the workpiece 1.

When the bending to the left side of the workpiece 1 is complete in Step 300, drive signal is outputted via the drive circuit 112d to the servo valve 114b so as to pull the rod 27b out of the hydraulic cylinder 27a. As a result, the clamping die 54 for left bend is separated from the bending die 6, the clamping of the workpiece 1 by the bending die 6 and the clamping die 54 for left bend is released. Also, at this point, drive signal is outputted via the drive circuit 112f to the servo valve 114d to pull the rod 73b out of the hydraulic cylinder 73a. As a result, the left pressure die 58 is separated from the workpiece 1.

In the current flow, if Step 310 is completed without execution of Stop 270, the workpiece 1 is still being gripped by the chuck 80 to be retained by the bending device 100.

On the other hand, if Step 310 is completed after the execution of Step 270, the workpiece 1 is fully released from the bending device 100.

Next, whether the bending of the workpiece 1 just completed is the final bending to the workpiece 1 is determined based on the data inputted from the outside to the CPU 102 (Step 320).

When it is negatively determined in Step 320, that is, if there is another bending to be performed to the other part of the workpiece 1 (Step 320: NO), the process moves to Step 210 and Steps 210 to 320 are repeated.

In the above process, it is negatively determined in Step 320 only if Step 270 is not executed in the current flow (if the workpiece 1 is still being gripped by the chuck 80 in Step 320).

FIGS. 10A and 10B show the case in which bending of the workpiece 1 to the left side is performed after the state shown in FIG. 9B.

In this case, firstly, the relative position between the bending die 6 and the clamping die 60 is changed from the first relative position to the second relative position (Step 210).

Particularly, by the control signal outputted via the drive circuit 112b to the solenoid 46, the second rotation mode (the state in which the projection 34 is separated from the recess 32) is achieved. In this state, by the control signal outputted via the drive circuit 112a to the motor 38, the bending shaft 8 is rotated by 180° via the drive shaft 36. As a result, the second relative position is achieved (see FIG. 10A). This process is executed in a state that the workpiece 1 is moved away from the moving paths of the bending die 6 and the clamping die 50, by the drive of the motors 116a, 116b, and 116c, as needed, so that the workpiece 1 does not get in the way of the bending die 6 and the clamping die 50.

Also, the workpiece 1 is arranged in the second linear section 4a3 or 4b3 of the bending die 6 in accordance with the bending shape of the workpiece 1, by the drive of the motors 116a, 116b, and 116c. By the drive of the motor 116a, the feed table 86 (workpiece 1) is moved and fed to the bending die 6 along the rails 84 (Step 220).

When the workpiece 1 has reached the bending position based on signal from the position sensor 110f (Step 230: YES), the move of the workpiece 1 by the feed mechanism 82 is stopped (Step 240).

In the above process, when Steps 210 to 320 are performed more than once in order to perform bending to plural parts of the workpiece 1, Step 210 for the second time onward is performed concurrently with Steps 220 to 240.

Next, the rod 27b is pulled into the hydraulic cylinder 27a by the output of drive signal to the servo valve 114b so as to produce a state in which the workpiece 1 is clamped between the bending die 6 and the claming die 54 for left bend (Step 250). At this point, the bending groove 58a or 58b of the left pressure die 58 is pressed against the outer periphery of the workpiece 1 by the drive signal to the servo valve 114d (see FIG. 10A).

Next, whether the bending to be executed to the workpiece 1 through Steps 280 to 300 out of Steps 210 to 320 currently in progress is the final bending to the workpiece 1 is determined based on the data inputted from the outside to the CPU 102 (Step 260).

When it is positively determined in Step 260, the workpiece 1 is released from the chuck 80 (Step 270), and the process moves to Step 280. On the other hand, when it is negatively determined in Step 260, the process moves to Step 280 without passing Step 270.

Next, while the first rotation mode (the state in which the projection 34 is engaged with the recess 32) is achieved by the control signal outputted via the drive circuit 112b to the solenoid 46, the bending die 6 and the clamping die 50 are rotated in a body to the left side L by the control signal outputted via the drive circuit 112a to the motor 38 (Step 280, FIG. 10B).

As a result, the workpiece 1 is bent to the left side. When it is determined that the bending angle of the workpiece 1 has reached the predetermined angle based on the detection value by the position sensor 110a (Step 290: YES), the bending is stopped (Step 300). FIG. 10B shows the state in which the process in Step 300 is completed when the “predetermined angle” at this point is around 180°. The clamping of the workpiece 1 is released (Step 310).

Steps 210 to 320 are repeated predetermined times based on data inputted from the outside to the CPU 102. When it is positively determined in Step 320 (Step 320: YES), the chuck 80 is returned to its original position by the control signal outputted via the drive circuits 112g, 112h, and 112i to the motors 116a, 116b, and 116c (Step 330). The present control process is terminated for the present.

As explained above, in the present embodiment, bending of the workpiece 1 to both the left and right sides can be achieved by setting the relative position between the bending die 6 and the clamping die 60 to the first relative position or the second relative position.

In other words, according to the present embodiment, the device configuration can be simple compared to the conventional device configuration since bending to both the left and right sides of the workpiece 1 can be achieved by a pair of bending die 6 and the clamping die 50.

Also, in the present embodiment, when the workpiece 1 is clamped between the bending die 6 and the clamping die 50, the workpiece 1 is clamped between the linear section 4a2, 4b2, 4a3, 4b3 of the bending groove 2a, 2b of the bending die 6 and the linear bending groove 52a, 52b, 54a, 64b of the clamping die 50.

Thus, according to the present embodiment, positional deviation hardly occurs between the bending die 6 and the clamping die 50 at the time of bending the workpiece 1, compared to the case in which, for example, clamping of the workpiece 1 is performed using the curved section 4a1, 4b1 of the bending groove 2a, 2b of the bending die 6.

In the present embodiment, the chuck 80 is designed to move in three directions, that is, the longitudinal direction (X direction), the lateral direction (Y direction), and the vertical direction (Z direction), by the feed mechanism 82. Accordingly, the present embodiment makes it easy to feed the workpiece 1 to the position necessary for bending using the bending die 6 and the clamping die 50.

The present invention is not limited to the above embodiment, and other modifications and variations are possible within the scope of the present invention.

For instance, in the above embodiment, both of the bending die 6 and the bending arm 12 (clamping die 50) are rotated through the transmission of the rotational force from the single motor 38.

However, two motors having the structure of the motor 38 may be provided as the drive force applicator. While the bending die 6 is rotated around the bending shaft 8 by the rotational force of one motor, the bending arm 12 (clamping die 50) may be rotated around the bending shaft 8 by the rotational force of the other motor.

Also, for example, in the above embodiment, only the bending die 6 out of the bending die 6 and the bending arm 12 (clamping die 60) is rotated around the bending shaft 8 in the second rotation mode.

However, in the second rotation mode, only the bending arm 12 (clamping die 50) out of the bending die 6 and the bending arm 12 (clamping die 50) may be rotated around the bending shaft 8.

Such configuration can be easily implemented in the above variation in which the bending die 6 is rotated by one of the two motors having the configuration identical to the configuration of the motor 38 while the bending arm 12 (clamping die 50) is rotated by the other of the motors.

Particularly, the first rotation mode is achieved in which both the bending die 6 and the bending arm 12 (clamping die 50) are rotated by driving both of the motors, while the second rotation mode is achieved in which only the bending arm 12 (clamping die 50) is rotated by driving only one of the motors that rotates the bending arm 12 (clamping die 50).

Claims

1. A bending device that bends a longitudinal workpiece, comprising: a bending die that has an outer shape corresponding to a bending shape; a clamping die that clamps the workpiece with the bending die; and a rotation mechanism that rotates the bending die and the clamping die to a predetermined bending direction while the workpiece is being clamped between the bending die and the clamping die, wherein the rotation mechanism includes a selection mechanism that allows switching between a first rotation mode in which the bending die and the clamping die are rotated in a body and a second rotation mode in which one of the bending die and the clamping die is rotated independently of the other die.

2. The bending device set forth in claim 1, wherein the rotation mechanism sets a relative position between the bonding die and the clamping die either to a first relative position, which is an initial position when bending the workpiece to a right side, and to a second relative position, which is an initial position when bending the workpiece to a left side, by rotating at least one of the bending die and the clamping die by means of the selection mechanism.

3. The bending device set forth in claim 1, wherein the rotation mechanism comprises a rotational force applicator that transmits a rotational force to at least one of the bending die and the clamping die, and the selection mechanism transmits the rotational force from the rotational force applicator to both the bending die and the clamping die in the first rotation mode, while the selection mechanism transmits the rotational force from the rotational force applicator to either of the bending die and the clamping die in the second rotation mode.

4. The bending device set forth in claim 3, wherein the selection mechanism transmits the rotational force from the rotational force applicator only to the bending die out of the bending die and the clamping die in the second rotation mode.

5. The bending device set forth in claim 1, wherein the bending die has a linear section in its outer shape, and the clamping die clamps the workpiece with the linear section of the bending die.

6. The bending device set forth in claim 2, wherein the bending die is provided with a first linear section in part of its outer shape facing the clamping die when the relative position between the bending die and the clamping die is in the first relative position, and a second linear section in part of its outer shape facing the clamping die when the relative position between the bending die and the clamping die is in the second relative position, and the clamping die clamps the workpiece with the first linear section of the bending die when the workpiece is being bent to the right side, while the clamping die clamps the workpiece with the second linear section of the bending die when the workpiece is being bent to the left side.

7. The bending device set forth in claim 1, wherein the clamping die includes a clamping die for right bend that clamps the workpiece with the bending die when bending the workpiece to a right side, and a clamping die for left bend that clamps the workpiece with the bending die when bending the workpiece to a left side.

8. The bending device set forth in claim 6, wherein the clamping die includes a clamping die for right bend that clamps the workpiece with the first linear section of the bending die when bending the workpiece to the right side, and a clamping die for left bend that clamps the workpiece with the second linear section of the bending die when bending the workpiece to the left side.

9. The bending device set forth in claim 7, wherein the clamping dies for right bend and left bend are arranged in such a manner that moving directions of the respective clamping dies when clamping the workpiece are nearly parallel to each other.

10. The bending device set forth in claim 1, wherein the bending die includes in its outer shape a plurality of bending die contact portions which correspond to a plurality of bending shapes of the workpiece, the clamping die includes in its outer shape a plurality of clamping die contact portions which correspond to a plurality of bending shapes of the workpiece, and when the workpiece is clamped between the bending die and the clamping die to be bent, the workpiece is clamped between one of the bending die contact portions and one of the clamping die contact portions respectively selected in accordance with the bending shape of the workpiece.

11. The bending device set forth in claim 7, wherein the bending die has in its outer shape a plurality of bending die contact portions which correspond to a plurality of bending shapes of the workpiece, the clamping die for right bend has in its outer shape a plurality of clamping die contact portions for right bend which correspond to a plurality of bending shapes of the workpiece, and the clamping die for left bend has in its outer shape a plurality of clamping die contact portions for left bend which correspond to a plurality of bending shapes of the workpiece, and when the workpiece is clamped between the bending die and the clamping die for right bend to be bent to a right side, the workpiece is clamped between one of the bending die contact portions and one of the clamping die contact portions for right bend respectively selected in accordance with the bending shape of the workpiece, and when the workpiece is clamped between the bending die and the clamping die for left bend to be bent to a left side, the workpiece is clamped between one of the bending die contact portions and one of the clamping die contact portions for left bend respectively selected in accordance with the bending shape of the workpiece.

12. The bending device set forth in claim 7, wherein when bending the workpiece to the right side, the clamping die for right bend is moved toward the bending die so that the workpiece is clamped between the bending die and the clamping die for right bend, when bending the workpiece to the left side, the clamping die for left bend is moved toward the bending die so that the workpiece is clamped between the bending die and the clamping die for left bend.

13. The bending device set forth in claim 1, further comprising a right pressure die that receives a bending reaction force generated when bending the workpiece to a right side, and a left pressure die that receives a bending reaction force generated when bending the workpiece to a left side.

14. The bending device set forth in claim 13, wherein the right pressure die and the left pressure die are disposed on both sides of the bending die.

15. The bending device set forth in claim 10, further comprising a right pressure die that receives a bending reaction force generated when bending the workpiece to a right side, and a left pressure die that receives a bending reaction force generated when bending the workpiece to a left side, the right pressure die includes a plurality of right pressure die contact portions corresponding to the shape of the workpiece, and the left pressure die includes a plurality of left pressure die contact portions corresponding to the shape of the workpiece, and when the workpiece is clamped between one of the bending die contact portions and one of the clamping die contact portions respectively selected in accordance with the bending shape of the workpiece to the right side, one of the plurality of right pressure die contact portions is in contact with the workpiece to receive the bending reaction force, and when the workpiece is clamped between one of the bending die contact portions and one of the clamping die contact portions respectively selected in accordance with the bending shape of the workpiece to the left side, one of the plurality of left pressure die contact portions is in contact with the workpiece to receive the bending reaction force.

16. The bending device set forth in claim 1, further comprising a chuck that grips the workpiece, and a feed mechanism that moves the chuck in a longitudinal direction of the workpiece and two directions which are directions orthogonal to the longitudinal direction so as to feed the workpiece between the bending die and the clamping die to be clamped therebetween.