JP2521911Y2 - Chuck opening and closing device in multi-stage press forming machine - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a chuck opening and closing operation in a multi-stage forging machine having a plurality of forging stations having opposed dies and punches, and a chuck for transferring a material between these forging stations. Related to the device.

[0002]

2. Description of the Related Art A multi-stage press forming machine for forming bolts, nuts, and other various parts is composed of a plurality of press forming stations having a die and a punch facing each other. In order to form a product having a predetermined shape by step-forming from coarse to fine, the material forming apparatus is provided with a material transfer device for sequentially transferring the material to a next-stage forging station.

As shown in FIGS. 10 and 11, this material transfer device is slidably supported by the front end of a support frame 80 and reciprocated in a direction in which the dies 82 are arranged side by side by a drive mechanism 81. A movable frame 83 is supported rotatably on a front surface of the movable frame 83 via a pair of support shafts 84, 84, and adjacent dies 82, 82
Chucks 85 to 85 reciprocated between front positions
And a pair of sector gears 86, 86 meshing with each other while being fixedly mounted on the intermediate portions of the support shafts 84, 84, respectively.
And a roller 87 eccentrically attached to the rear end of one of the support shafts 84 and a cam shaft 88 that rotates in synchronization with the movement of a punch (not shown) that moves toward and away from each of the dies 82. And each chuck 8 attached to the cam shaft 88.
The cam plates 89A, 89B for each of the five and the cam followers for swinging with the rotation of the cam plates 89A, 89B, thereby rotating the support shaft 84 to which the rollers 87 are attached to open and close the chucks 85. 90, the material held by the chucks 85 is transferred from the former forging station to the latter forging station, and each chuck 85 is moved with the advance of the punch.
, The material is released, the forging by the punch is performed, and then the returning of these chucks 85 to the original position is repeated.

[0004] When forming products having different shapes by one press forming machine, it is necessary to adjust the opening and closing timing of the chuck 85 in accordance with the shape of the formed product to be formed. Therefore, for example, Japanese Utility Model Laid-Open No. 4-478
In Japanese Patent Publication No. 36, as shown in FIG. 11, two cam plates (89A, 89B) are provided for each chuck 85, and the mutual phases of these cam plates 89A, 89B are adjusted (in other words, the cam plates). A technique is disclosed in which by adding a phase adjustment operation (changing the overlapping state of the 89A and 89B viewed from the cam shaft 88 in the axial direction), the opening and closing operation of the chuck 85 is at a timing suitable for the shape of the molded product. ing.

[0005] Further, the above publication discloses that the cam plate 89A,
Hydraulic cylinders are provided on both sides of 89B, and after the above-described phase adjustment, the two cam plates 89A and 89B are sandwiched and fastened by hydraulic pressure, and the two cam plates 89 are maintained while maintaining the adjusted phase relationship.
A technique is also disclosed in which A and 89B are integrally rotated, and the hydraulic pressure is released during the phase adjustment so that the cam plates 89A and 89B are fastened.

[0006]

In the technique disclosed in the above publication, the hydraulic cylinders are arranged on both sides of the cam plates 89A and 89B for the mutual fastening of the cam plates. In this case, a large number of hydraulic cylinders are required, and complicated processing such as processing for mounting these hydraulic cylinders and forming an oil path for the cam shaft for supplying and discharging hydraulic oil is required. The structure of the forging machine becomes complicated and the cost is increased.

Accordingly, an object of the present invention is to provide a chuck opening and closing device in a multi-stage press forming machine capable of adjusting the opening and closing timing of the chuck with a simple configuration.

[0008]

That is, a device according to claim 1 of the present invention (hereinafter referred to as a first device) is provided with a plurality of forging stations having a die and a punch. A plurality of chucks which reciprocate at a predetermined timing with respect to the forging operation in the station, hold and transfer the material from the preceding forging station to the subsequent forging station are provided, and the reciprocating movement of the chuck and the punch is provided. A chuck opening / closing device in a multi-stage press forming machine provided with a plurality of cam units for opening and closing respective chucks on a cam shaft that rotates in conjunction with the above, wherein each of the cam units is a pair of cam plates. And a pair of cam holders which are arranged on both sides of these cam plates and which rotate together with each cam plate. These are fitted so as to be capable of relative rotation and axial movement with respect to the camshaft, and the two cam plates in each cam unit are individually rotated relative to each other via the corresponding cam holders, whereby A timing adjusting means for changing the opening / closing timing of the chuck is provided. On the other hand, a collar is fitted between the cam units on the camshaft such that these cam units correspond to the intervals at which the chucks are arranged. At the same time, a large-diameter flange portion is provided at one end of the camshaft, and at the other end of the camshaft, each of the cam plates and cam holders constituting each of the cam units is provided. A cylinder for fixing each cam unit to the cam shaft by sequentially pressing the collar against the flange portion is provided so as to be integrally rotatable with the cam shaft. The features.

Further, the invention according to claim 2 (hereinafter referred to as a second invention)
The collar fitted between the cam units on the camshaft is fitted to the camshaft so as to be movable in the axial direction and to rotate integrally with the camshaft. When the unit is pressed, the rotational force of the camshaft is transmitted to each cam unit via these collars.

Further, according to the invention described in claim 3 (hereinafter referred to as a third invention), each of the two cam plates in each cam unit is divided into two, and pins are respectively attached to the cam holders on both sides. And at least one of a collar on the camshaft and the cam unit closest to the cylinder or at least one between the flange portion and the cam unit closest to the cylinder. A cam plate in each cam unit and a cam engaged with the cam plate via a pin are provided by an axial space on the cam shaft generated when the collar is disassembled and removed from the cam shaft. It can be separated from the holder,
The cam plate divided into two parts is detachable from the cam shaft.

[0011]

According to the first aspect of the present invention, each of the cam units and the collar is pressed against the flange at one end of the camshaft by exerting a pressing force in the direction of one end of the camshaft by the cylinder provided at the other end of the camshaft. As a result, a pinching force acts on all the cam units between the cylinder and the flange portion, and the two cam plates in each cam unit are fastened. Further, when the pressing force of the cylinder is released, the pinching force between the cylinder and the flange portion is also eliminated, and the fastening of the two cam plates in each cam unit is also cut off. Therefore, a plurality of cam units in a multi-stage press forming machine can be fastened and unfastened by one cylinder.

According to the second aspect of the present invention, the collar is configured to rotate integrally with the camshaft when the respective cam units are fastened by the cylinder as described above. Therefore, the torque of the camshaft is transmitted via the collar. Is transmitted to the cam unit. Therefore, even the cam units located far from the cylinder and the flange portion can reliably transmit torque by the collars arranged on both sides thereof, and the cam plates in these cam units rotate without slipping.

According to the third aspect of the present invention, at least one between the cylinder and the cam unit closest to the camshaft or between the flange and the cam unit closest to the cylinder on the camshaft. If the collar provided on the cam unit is disassembled and removed from the camshaft, the resulting space in the axial direction on the camshaft is used to disengage the cam plate and the cam holder in each cam unit, thereby removing
The divided cam plate can be removed, and when a new cam plate is set after the removal, the mounting can be performed in the reverse order of the above. Therefore, replacement of the cam plate
It can be performed without sequentially pulling out the cam plate and the cam holder from the end of the cam shaft.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a multi-stage press forming machine 1 to which the present invention is applied. A die block 3 having a plurality of dies D to D (see FIG. 2) arranged at regular intervals on a machine base 2 is provided. A ram 4 is provided so as to face the die block 3, and the same number of punches P to P as the die D are provided on the front surface of the ram 4.
Is attached. In this case, the ram 4 is connected to a crank arm of the crankshaft 5 via a rod 6, and the torque of the drive motor 7 is transmitted to the crankshaft 5 by the pulleys 8, 9 and the belt 10, whereby the crankshaft 5 is rotated.
The ram 4 is moved back and forth once for each revolution of the punches, and the punches P to P move forward and backward with respect to the dies D to D by this back and forth movement,
A predetermined forming operation of the material is performed at four forging stations including a die and a punch.

On the other hand, a chuck block support frame 12 is mounted on a base shaft 11 on the machine base 2 described above. A front end of the support frame 12 is mounted on a die block, and a chuck block 13 is mounted on the front end. Die D ~ D
Are swingably supported in the juxtaposed direction. The rotation of the crankshaft 5 is taken out by the gears 14A to 14D and transmitted to the drive shaft 16 supported by the bracket 15 on the side of the machine base, and the rotational force is fixed to the drive shaft 16. Is input to the chuck block 13 via the lever 18 by the cam 17, whereby the chuck block 13 reciprocates in synchronization with the forward and backward movement of the ram 4, and the chucks 19 to 1 provided on the chuck block 13 are moved.
9 is moved between adjacent dies.

Further, the rotational force of the drive shaft 16 is
0A and 20B are input to the rotational force transmission mechanism 21,
The camshaft 23 (see FIGS. 3 to 5) which is linked to the torque transmitting mechanism 21 by gears 22A and 22B is driven. The cam shaft 23 opens and closes the chucks 19 to 19. When the cam shaft 23 rotates in synchronization with the crankshaft 5, the chucks 19 to 19 also open and close in synchronization with the forward and backward movements of the ram 4. Is done.

As shown in FIGS. 2 and 3, the chuck block 13 is slidably supported at the front end of the support frame 12 and is provided with the die D by the lever 18 described above.
To a movable frame 24 which is reciprocated in the juxtaposed direction, and a pair of support shafts 2 on a front surface of the movable frame 24.
The plurality of chucks 19 to 19 are freely rotatable through 5, 25.
19 are supported. In this case, a pair of sector gears 26, 26 meshing with each other in a state of being fixedly mounted on the intermediate portions of the respective support shafts 25, 25 are provided, and a roller 27 is mounted eccentrically on the rear end of one of the support shafts 26. ,
A cam unit 28 for each chuck is provided on the cam shaft 23 described above.
A cam follower 30 corresponding to each cam unit 28 is mounted on a shaft 29 provided in parallel with the vicinity of the cam shaft 23 (described later in detail). One end of each of the cam followers 30 is a spring. 31 is constantly pressed against the cam unit 28. The other end of the cam follower 30 is in contact with the roller 26 described above.

Therefore, when the cam unit 28 rotates, the support shaft 2 is driven via the cam follower 30 and the roller 27.
5, the chuck 19 is opened and closed.

Next, the cam shaft 23 and the cam unit 28 will be described in detail. 4 and 5, both ends of the camshaft 23 are rotatably supported by brackets 32 and 33 on the machine base 2 via bearings 34, and the camshaft 23 is at one end side more than the bracket 32 that supports the one end. Camshaft 2 inside
A flange portion 35 having a diameter larger than 3 is formed, and a hydraulic cylinder 36 is mounted on the other end side at a position inside the bracket 33 supporting the other end. The hydraulic cylinder 36 includes a cylinder tube 38 fixed to the camshaft 23 and a cylinder chamber 38 opening toward one end of the camshaft. A piston 39 is fitted in the cylinder chamber 38, and the camshaft 23 A hydraulic oil supply / discharge control unit 40 is attached to a shaft end of the cylinder shaft 38.
The piston 39 is pressed in one direction of the camshaft 23 when hydraulic oil is supplied to the cylinder chamber 38.

On the other hand, as shown in FIGS. 4 to 7, each of the above-mentioned cam units 28 is a pair of two cam plates 42.
A and 42B, and a pair of cam holders 43A and 43B arranged on both sides of these cam plates 42A and 42B and integrally rotating with the respective cam plates.

In that case, the respective cam plates 42A, 42
B is divided into two halves so that it can be fitted into the cam shaft 23 from the side and can be detached from the cam shaft 23. When these halved cam plates 46 and 47 are combined, the cam plate A through hole 44 through which the camshaft 23 passes is formed at the center of each of 42A and 42B, and a circular annular convex step 45 is formed on the side facing the cam holders 43A and 43B. Further, engaging grooves 48, 49 communicating with the through holes 44 are formed in the respective half cam plates 46, 47 in a direction perpendicular to the center of the through hole 44 and at the center positions of the respective divided cam plates 46, 47. At an angle phase of 180 degrees.

On the other hand, the cam holders 43A and 43B have a gear 50 formed on the outer periphery thereof, a through hole 51 through which the cam shaft 23 passes in the center, and cam plates 42A and 43B.
An annular convex step 52 having an outer diameter fitted inside the through hole 44 of the cam plate on the side facing 42B, and a convex step 45 of the cam plates 42A and 42B fit around the convex step 52. A concave step 53 having a shape is formed, and 180
The two pins 54 and 55 are set at the concave
3 are protruded.

In the cam unit 28, each cam plate 4 is located between the two cam holders 43A and 43B.
The two half-split cam plates 46 and 47 constituting each of 2A and 42B are fitted from the side of the cam shaft 23. At this time, the through holes 4 of the respective cam plates 42A and 42B
The convex steps 52 of the cam holders 43A and 43B holding the cam plates 42A and 42B are fitted in the cam holders 4 and 44, and the convex steps 45 of the cam plates 42A and 42B are
The cam plates 42A, 42B are fitted to the cam holders 43A, 43B by fitting the pins 54, 55 into the engaging grooves 48, 49 while fitting them into the concave steps 53 of the 3A, 43B.
Attach with B in phase. The pair of pins 48 and 49 have different diameters, and the diameters of the engagement grooves 48 and 49 on the half-split cam plates 46 and 47 are changed accordingly, so that the cam holders 43A and 43B are formed. On the other hand, mistakes such as mounting the half-split cam plates 46 and 47 in reverse to those in FIG. 8 can be prevented, which is convenient.

In addition, between each cam unit 28, between the flange portion 35 of the camshaft 23 and the end cam unit 28 adjacent thereto, and between the cam cylinder 28 and the hydraulic cylinder 3
Collars 56 to 56 are respectively fitted between the piston 39 and the end cam unit 28 adjacent to the piston 39 in FIG. These collars 56 to 56 are movable by a predetermined amount in the axial direction of the camshaft 23, and
3 so as to be integrally rotatable. That is,
FIG. 5, FIG.
As shown in FIGS. 6 and 8, an axial key groove 57 is formed, a radial screw hole 58 is provided on the collar side, and the collar 56 is inserted into the screw hole 58 with the collar 56 fitted on the cam shaft 23. By engaging the tip of the screwed bolt 59 with the key groove 57, the collar 56 can be rotated integrally with the camshaft 23, and when a pressing force in the camshaft direction is applied by the hydraulic cylinder 36 described above. , Can be moved in the axial direction as long as the length of the key groove 57 permits.

Further, each of the cam units 28 to 28 has
Each gear 5 of the pair of cam holders 43A, 43B
A pair of transmission gears 60 and 61 meshing with the transmission gears 0 and 50 are provided on the intermediate shaft 62 as many as the number of the cam units 28, and a pair of transmission gears 63 meshing with the transmission gears 60 and 61 are also provided. , 64 are provided by the number of the cam units 28, and the respective drive gears 63, 6 are provided.
4 are connected to motors 65 and 66 via clutches 67 and 67. The transmission gears 60 and 61, the drive gears 63 and 64, the motors 65 and 66, and the clutch 6
7 constitutes timing adjusting means for changing the opening / closing timing of the chuck 19.

Further, among the aforementioned colors 56 to 56,
A hydraulic cylinder 36 attached to the camshaft 23;
As shown in FIG. 9, the collar interposed between the cam unit 28 mounted on the cam shaft 23 and the collar closest to this is composed of half-split collars 71 and 72 divided into two. Split the split collars 71 and 72 to the camshaft 2
3, the bolt 70 is screwed into a pair of screw holes 68 provided in one of the half collars 72 through bolt through holes 69 formed in the other half of the collar 71, whereby the two half collars 71, 72 are integrally fastened, and a half collar 7 is formed in a key groove 57 provided in the cam shaft 23 similarly to the other collars 56 to 56.
By screwing a bolt 59 through 1, the integrated collar 56 </ b> A is engaged with the camshaft 23, and the collar 56 </ b> A is configured to rotate integrally with the camshaft 23. The flange portion 35 formed on the cam shaft 23 and the collar 56B attached to the cam shaft 23 closest to the flange portion 35 have the same structure as the collar 56A.

In the multi-stage press forming machine 1 having such a configuration, the supply / discharge control unit 40 controls the hydraulic cylinder 3
When the piston 39 is moved toward the flange 35 at the opposite end of the camshaft 23 by supplying hydraulic oil to the cam unit 6, the cam units 28 to 28 and the collars 56 to 56, 56A, 5
6B is pressed and sandwiched between the flange portion 35 and the piston 39, so that in each cam unit 28, the cam holders 43A, 43B are formed by a pair of cam plates 42A, 42B.
B, and the two cam plates 42A and 42B are fastened by the force. Therefore, if the cam shaft 23 is rotated, each cam unit 28 is rotated while maintaining the relative phase between the cam plates 42A and 42B.

In this case, since the cam unit 28 located at the center of the cam shaft 23 is located far from the hydraulic cylinder 36 and the flange 35 that generate the fastening force,
It is conceivable that a shortage of the fastening force occurs, and a problem occurs in torque transmission to the cam plates 42A, 42B. However, the collar 5 holding the cam unit 28 from both sides
As described above, the collars 6 and 56 are engaged with the cam shaft 23 by the key groove 57 and the bolt 59 and are configured to rotate integrally with the cam shaft 23. Rotational force is input to the cam holders 43A and 43B via the pin 56, and this is applied to the pins 54,
Since the power is transmitted to the cam plates 42A and 42B by the engagement configuration between the 55 and the engagement grooves 48 and 49 on the cam plate side, the cam plates 42A and 42B rotate together with the cam shaft 23 without causing torque shortage. .

If the hydraulic oil is removed from the hydraulic cylinder 36 while the camshaft 23 is stopped to release the pressing force,
There is no pinching force between the hydraulic cylinder 36 and the flange 35, and the fastening of the cam plates 42A, 42B is written in a square. Therefore, when the phase adjustment of the cam plates 42A and 42B is performed, the clutch 67 corresponding to these cam units is turned off in the cam unit 28 that needs to be adjusted.
N, one or both of the motors 66, 67 are rotated, and one or both of the cam holders 43A, 43B are rotated via one or both of the transmission gears 60, 61, so that the pins 54, 55 Engagement grooves 48, 49
The cam plates 42A and 42B are rotated relative to each other by using the engagement structure with the above, and the phases of the two cam plates 42A and 42B are adjusted. Then, after the phase adjustment of all the cam units 28 that need to be adjusted, the hydraulic cylinder 36 is operated again with the clutch 65 turned off, and the cam plates 42A and 42B of each cam unit 28 are fastened.

Therefore, in the multi-stage press forming machine 1 of the present embodiment, the cam plates 28 to 28 can be fastened by one hydraulic cylinder 36 regardless of the number of the cam units 28 attached. Is simplified.

Further, depending on the product to be forged, the phase adjustment of the cam plates 42A and 42B may not be completed, but the cam plate itself must be replaced. At that time, the cam plates 42A, 42B by the hydraulic cylinder 36 are used.
Of the collars 56-56, 56A, 56B attached to the camshaft 23, the collars 56A, 56B at both ends of the camshaft are disassembled by removing the bolts 70, 70, and the half-split collars 71, 56 are removed. 72 is removed from the camshaft 23. As a result, as shown in FIG. 6, spaces X are formed at both ends of the cam shaft, and these spaces X are used to make up the cam plates 42A, 42 constituting the cam unit 28.
B, The cam holders 43A and 43B can be disassembled as shown in FIG. 9 by sliding them in the axial direction. If you do this,
Pins 54, 55 on the cam holder side and engaging groove 4 on the cam plate side
8 and 49 are disengaged, and the half-split cam plates 46 and 4 are disengaged.
7 is removed from the camshaft 23, the cam plate 42 is removed.
A and 42B can be removed, and a new cam plate can be mounted on the cam shaft 23 in the reverse procedure.

In this case, the collars 56A and 56B and the cam plates 42A and 42B are each divided into two parts, and can be attached to and detached from the cam shaft 23 from the side perpendicular to the axis of the cam shaft 23. After removing the entire camshaft 23 from the brackets 32 and 33 as described above, the cumbersome work of extracting each cam unit from one end of the camshaft and replacing the cam plate is eliminated, and the replacement work can be performed easily and quickly. .

[0034]

As apparent from the above description, according to the first aspect of the present invention, each cam unit can be operated by applying a pressing force in the direction of one end of the cam shaft by a cylinder provided at the other end of the cam shaft. In addition, the collar is pressed against the flange portion at one end of the camshaft, so that a pinching force acts on all the cam units between the cylinder and the flange portion, and the two cam plates in each cam unit are fastened. You. Further, when the pressing force of the cylinder is released, the pinching force between the cylinder and the flange portion is also eliminated, and the fastening of the two cam plates in each cam unit is also cut off. Therefore, a plurality of cam units in a multi-stage press forming machine can be fastened and unfastened by one cylinder,
The structure of the chuck opening / closing device can be greatly simplified.

According to the second aspect of the present invention, the collar is adapted to rotate integrally with the camshaft when the respective cam units are fastened by the cylinder as described above, so that the torque of the camshaft is transmitted via the collar. Is transmitted to the cam unit. For this reason, the collars arranged on both sides of the cam units located far from the cylinder and the flange portion also reliably transmit torque, and the cam plates of these cam units rotate without slipping.

According to the third aspect of the present invention, at least one of the two parts is provided between the cylinder on the camshaft and the cam unit closest thereto, or between the flange and the cam unit closest thereto. If the collar provided on the cam unit is disassembled and removed from the camshaft, the resulting space in the axial direction on the camshaft is used to disengage the cam plate and the cam holder in each cam unit, thereby removing
The divided cam plate can be removed, and when a new cam plate is set after the removal, the mounting can be performed in the reverse order of the above. Therefore, replacement of the cam plate
Since the cam plate and the cam holder can be performed without being sequentially removed from the end of the cam shaft, the replacement of the cam plate can be performed easily and quickly.

[Brief description of the drawings]

FIG. 1 is a plan view of a multi-stage press forming machine according to an embodiment of the present invention.

FIG. 2 is a front view of a die block side of the molding machine.

FIG. 3 is a sectional side view of a chuck opening / closing device of the molding machine.

FIG. 4 is a front view of a cam shaft portion of the chuck opening / closing device.

FIG. 5 is a plan view of the cam shaft.

FIG. 6 is a plan view showing a state where a collar of the cam shaft is partially removed.

FIG. 7 is an exploded sectional view of the cam unit.

FIG. 8 is a view taken along line BB in FIG. 7;

FIG. 9 is an enlarged view taken along line AA in FIG. 4;

FIG. 10 is a front view of a conventional die block.

FIG. 11 is a cross-sectional side view of the conventional example.

[Explanation of symbols]

 Reference Signs List 1 multi-stage press forming machine 19 chuck 23 cam shaft 28 cam unit 35 flange 36 hydraulic cylinder 42A, 42B cam plate 43A, 43B cam holder 48, 49 engagement groove 50 gear 54, 55 pin 56 color 56A, 56B color 57 key Groove 59 Bolt 63, 64 Gear 65, 66 Motor D Die P Punch

Continuation of the front page (56) References JP-A-49-10864 (JP, A) JP-A-57-50234 (JP, A) JP-A-49-37867 (JP, A) JP-A-4-47836 (JP) , U) Japanese Utility Model Application Hei 5-28535 (JP, U) Japanese Utility Model Application Hei 5-39736 (JP, U) Japanese Utility Model Application Showa 60-71447 (JP, U) Japanese Utility Model Application Showa 62-142448 (JP, U)

Claims (3)

(57) [Scope of request for utility model registration] 1. A forging station having a die and a punch is provided in a plurality of stages, and reciprocates at a predetermined timing with respect to a forging operation in each station, and a material is transferred from a former forging station to a latter forging station. And a plurality of cam units for opening and closing the respective chucks on a cam shaft that rotates in conjunction with the reciprocating movement of the chucks and the punches. A chuck opening / closing device in a molding machine, wherein each of the cam units is a set of two cam plates and a pair of cam plates arranged on both sides of these cam plates and rotated integrally with each cam plate. And a cam holder, which are fitted so that they can rotate relative to the camshaft and move in the axial direction. Timing adjustment means for changing the opening / closing timing of the chuck by individually rotating the two cam plates of the cam unit via the corresponding cam holders is provided. On the other hand, each cam on the camshaft is provided. Between the units, a collar is fitted so that these cam units correspond to the arrangement intervals of the chucks, and a large-diameter flange portion is provided at one end of the cam shaft, and On the other end of the cam shaft, a cylinder for fixing each cam unit to the cam shaft by sequentially pressing each cam plate and each cam holder and each collar constituting each cam unit against the flange portion. A chuck opening / closing device in a multi-stage press forming machine, which is provided so as to be able to rotate integrally with a cam shaft. 2. A collar fitted between the cam units on the camshaft is fitted to the camshaft so as to be movable in the axial direction and to rotate integrally with the camshaft. 2. The chuck opening / closing device in a multi-stage press-forming machine according to claim 1, wherein, at the time of pressing, the rotational force of the camshaft is transmitted to each cam unit via these collars. 3. The two cam plates in each cam unit are each divided into two and engaged with cam holders on both sides via pins, respectively. Between the close cam unit,
Alternatively, at least one between the flange portion and the cam unit closest to the flange portion is provided with a collar that is also divided into two parts, and the collar is disassembled and removed from the cam shaft. The cam space in each cam unit and the cam holder engaged with the cam plate via a pin can be separated by the space in the axial direction, and the cam plate divided into two can be removed from the cam shaft. The chuck opening and closing device in the multi-stage press forming machine according to claim 1 or 2, wherein