JPH07116734A - Method and device for exchanging die in press brake - Google Patents

Abstract

PURPOSE:To unnecessitate centering in a time of attaching and detaching a punch and a die by making a punch holder, a die holder holding a punch and a die preliminarily centering as a pair and feeding them at the same time to the upper and lower tables of a press brake. CONSTITUTION:A punch 3 and a die 5 are attached on a punch holder 15 and a die holder 17, a moving side's table is moved up and down, the punch and the die are joined, centering of the punch 3 and the die 5 is executed, and the punch 3 and the die 5 are fixed on the punch holder 15 and the die holder 17. The punch holder 15 and the die holder 17 are received as a pair in each die receiving part 77 of a moving rack 75. By moving the moving rack 75, the required die receiving part 77 is positioned at the die changing position of upper and lower tables of a press brake. The punch holder 15 and the die holder 17 are extruded until a prescribed position of the upper and lower tables at the same time, fixed with a fixing device, and attaching the punch 3 and the die 17 onto the press brake is completed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for exchanging molds in a press brake, and more specifically, it maintains a state where a punch as an upper mold and a die as a lower mold are centered. And a method for simultaneously exchanging them.

[0002]

2. Description of the Related Art As prior arts relating to the present invention, for example, Japanese Examined Patent Publication No. 55-45288 (hereinafter referred to as Prior Art 1), Japanese Examined Patent Publication No. 1-53130 (Preceding Example 2) and Japanese Utility Model No. 2
No. 30087 (publication example 3) is available.

[0003]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
The punch (upper die) and the die (lower die) for the upper and lower tables of the press brake are individually replaced by separate exchanging devices. Therefore, it is convenient when changing the combination of the punch and the die to process the work, but it is necessary to perform the centering action of the punch and the die every time the punch and the die are exchanged, which requires time for the setup work. There is a problem that it requires.

Further, in the prior art example 3, the punch and die can be replaced simultaneously or individually with respect to the upper and lower tables in the press brake, which is more convenient, but again the centering of the punch and die is performed. There is a problem that needs to be done.

Further, in the prior art, the die accommodating portion accommodating the punch and die to be exchanged is configured to rotate up and down, and the accommodation state of the punch and die is inverted upside down. The punch and the die must be housed in the mold housing so that there is no problem even at times, and there are problems that the structure of the mold housing is complicated and that the die has rigidity.

In any case, in the prior art,
When punches and dies are attached / detached to / from the upper and lower tables in the press brake, it is necessary to perform centering work for the punches and dies each time, so that it is impossible to perform continuous machining by a program, for example. was there.

[0007]

In view of the above-mentioned conventional problems, the method of the present invention is a method for exchanging molds in a press brake, and (a) is movable in the longitudinal direction to the upper table in the press brake and Attaching the punch to a punch holder that is fixedly fixed at a predetermined position;
(B) mounting a die corresponding to the punch on a die holder that is mounted on a lower table of a press brake so as to be movable in the longitudinal direction and fixed at a predetermined position;
(C) a step of vertically moving one table in the press brake to engage the punch and the die to center the pair of punch and die; and (d) a punch after centering. A step of simultaneously storing a pair of a punch holder holding a die and a die holder in an appropriate same die accommodating portion of a movable rack in a die accommodating device arranged on the side of a press brake; and (e) a. , B, c, d, the steps of accommodating the pre-centered punches, the plurality of pairs of punch holders holding the dies, and the die holders in the respective mold accommodating portions of the movable rack in the mold accommodating device.
(F) A desired die accommodating portion of the movable rack in the die accommodating device is positioned at a die exchanging position which is a lateral position of the upper and lower tables of the press brake, and the punch is pre-centered and the punch holding the die. A method of exchanging a die, which comprises the step of simultaneously sending a pair of a holder and a die holder to the upper and lower tables.

[0008] Further, in the mold exchanging method, the mold accommodating portions of the movable rack in the mold accommodating device are arranged in parallel in the front-rear direction, and the moving direction of the movable rack is the front-rear direction.

In the mold exchanging device, a movable rack having a plurality of mold accommodating portions arranged side by side in the front-rear direction is movably provided in the front-rear direction in a mold accommodating device arranged at a side position of a press brake. In the press brake, a punch centered in advance, a punch holder holding a die, and an upper holder support portion and a lower holder support portion, which are freely supported by a pair of die holders, are provided separately in the mold storage portions in the vertical direction. A punch holder supported by the upper and lower tables, a pair of punch holders which can be simultaneously drawn into any die accommodating portion and are accommodated in the die accommodating portions positioned corresponding to the upper and lower tables, The die carrying device is provided with a holder loading / unloading device capable of simultaneously pushing out the die holder to the upper and lower tables.

Further, each mold accommodating portion provided in the movable rack is opened at the lower side, and the holder loading / unloading device is provided with a guide portion below the movable rack and has a pair of punch holder and die holder. It is provided with a holder clasp that can hold one end side.

[0011]

In the above structure, the punch holder and die corresponding to the punch holder and the die holder mounted at the predetermined positions of the upper and lower tables of the press brake are attached with the punch and the die, respectively, and after the punch and the die are centered, the holder is carried in and out. By simultaneously pulling the punch holder and the die holder into the mold storage part of the movable rack in the mold storage device by the device, the punch in the state of being pre-centered in the mold storage part, the punch holder holding the die, The die holders are stored in pairs.

After arranging an arbitrary die accommodating portion of the movable rack at a die exchanging position corresponding to the upper and lower tables of the press brake, a pair of punch holders accommodated in the die accommodating portion are arranged, By simultaneously pushing out the die holder by the loading / unloading device and mounting the die holders at predetermined positions on the upper and lower tables, the punch holders, the punches mounted on the die holders, and the cores of the dies are inevitably aligned. It is not necessary to center the punch and die again.

Therefore, after the punches and dies are exchanged, machining can be performed without centering, and continuous machining can be performed by a program.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In order to facilitate understanding, an embodiment of the present invention will be described. First, as a general structure, a schematic structure of a press brake and a mold exchanging device and their positional relationship will be described. .

Referring to FIG. 1, a die exchanging device 7 for detaching and exchanging a punch (upper die) 3 and a die (lower die) 5 with respect to the press brake 1 includes a side portion of the press brake 1. It is located in the position.

The press brake 1 comprises an upper table 11 on the upper side of a C-shaped side frame 9 and a lower table 13 on the lower side, like a general press brake. One of the upper and lower tables 11 and 13 is a movable table, and is configured to be vertically driven by a driving device (not shown) such as a ball screw mechanism rotated by a hydraulic cylinder or a servomotor.

A long punch holder 15 having the punch 3 mounted thereon is detachably mounted on the lower portion of the upper table 11 in the press brake 1, and the die 5 is mounted on the upper portion of the lower table 13. A long die holder 17 is detachably attached.

As shown in FIGS. 3 to 5, the punch holder 15 is made of a plate material having a rectangular cross section, and the dimension in the left-right direction (longitudinal direction) is the left-right direction of the upper table 11. It is formed to be slightly shorter than the dimension.
As shown in FIGS. 3 to 5, on the front surface and the rear surface of the punch holder 15, a groove 15 having an inclined surface 15F formed on the upper side is formed.
G is formed over the entire length in the left-right direction, and a protrusion 15P is provided over the entire length in the left-right direction at the center of the lower surface in the front-rear direction (left-right direction in FIGS. 3 to 5).

The punch 3 is detachably attached to the lower portion of the punch holder 15 via a plurality of intermediate plates 21. The intermediate plate 21 can be attached to the lower portion of the punch holder 15 by reversing the front and rear, and is sandwiched between the plurality of clamp pieces 19 attached to the front and rear surfaces of the punch holder 15 by bolts and the projecting portion 15P. It is fixed.

The intermediate plate 21 is for adjusting the curvature of the punch 3 in a state where the central portion of the punch 3 in the longitudinal direction is projected downward, and the upper plate 23 having a substantially Z-shaped cross section and the upper plate. The wedge member 25 is adjustable in the left-right direction by contacting the inclined upper surface with the inclined lower surface 23 (the inclined state is not shown).

The punch 3 has the wedge member 25.
It is supported by the intermediate plate 21 via a clamp piece 27 attached to the upper plate 23 via a bolt so that the downward bending can be adjusted by adjusting.

Since it is well known that the wedge members 25 of the plurality of intermediate plates 21 are adjusted so that the central portion of the punch 3 projects downward, it is well known that the bending of the punch 3 is adjusted. Is omitted.

The die holder 1 supporting the die 5 for bending a plate-like work in cooperation with the punch 3.
7 is provided with the same length as the punch holder 15.
The die holder 17 has a rectangular cross section as shown in FIG. 3, and a flange portion 17F is formed on the front and rear surfaces of the lower portion over the entire length in the left-right direction (the direction orthogonal to the paper surface in FIG. 3). I am doing it.

A plurality of front and rear regulating members 29 are integrally attached to the front and rear surfaces of the die holder 17 and at appropriate intervals in the longitudinal direction of the die holder 17. A die base 31 is mounted on the upper surface of the die holder 17 and between the front and rear regulating members 29, and the die 5 is mounted on the upper surface of the die base 31.

The die base 31 includes the front and rear regulating members 2
A plurality of bolts 33 penetrating 9 are screwed and fixed so as to be slightly adjustable in the front-rear direction (left-right direction in the drawing). That is, for example, a spacer can be interposed between the front and rear restricting members 29 and the die base 31 to allow slight adjustment. It is also possible to slightly adjust the die base 31 with respect to the die holder 17 in the front-rear direction by attaching a push bolt and a pull bolt to the regulating member 29 and adjusting the push bolt and the pull bolt. The configuration of can be adopted.

However, the punch holder 15 and the die holder 1 are attached to the upper and lower tables 11 and 13 of the press brake 1.
When the punch 3 and the die 5 are engaged with each other when the punch 7 and the die 3 are mounted with high accuracy and the punch 3 and the die 5 have a center in the front-back direction in advance, Coordination is not always necessary.

A guide member 35 extending in the left-right direction is attached to the lower surface of the upper table 11 so that the punch holder 15 having the punch 3 mounted thereon can be attached to and detached from the upper table 11 as described above. A plurality of guide brackets 37 are attached to the front and rear surfaces of the upper table 11 at appropriate intervals in the left-right direction. A plurality of guide rollers 39 that guide the inclined surface 15F of the punch holder 15 are rotatably attached to the lower portion of the guide bracket 37.

Further, as shown in FIG. 3, positioning devices 41 are mounted at a plurality of positions on the rear surface of the upper table 11. In the present embodiment, the positioning device 41 comprises a cylinder block 43 in which a piston 43P is movably installed.
Is pushed by the piston 43P,
A pressing lever 45, which is capable of pressing the inclined surface 15F of the punch holder 15 upward, is pivotally mounted via a pin 47.

With the above structure, the working fluid is supplied to the cylinder block 43 of the positioning device 41, and the piston 4
When the pressing lever 45 is pressed by 3P, the punch holder 15 is pressed and positioned by the tip of the pressing lever 45 so as to be in close contact with the lower surface of the guide member 35 and the inner side surface of the guide bracket 37.

In order to fix the punch holder 15 positioned as described above, upper fixing devices 49 are mounted at a plurality of positions on the rear surface of the upper table 11 as shown in FIG. The upper fixing device 49 is composed of a cylinder block 51 in which a piston 51P that can press and fix the punch holder 15 toward the guide bracket 37 is movably installed.

With the above structure, by supplying the working fluid into the cylinder block 51, the punch holder 15 is pressed and fixed to the guide bracket 37 side by the piston 51P.

If the pressing lever 45 of the positioning device 41 is strongly pressed, the upper fixing device 49 can be omitted.

The die holder 17 supporting the die 5
As shown in FIG. 3, a guide member 53 is attached to the upper surface of the lower table 13 so that the lower table 13 can be attached to and detached from the lower table 13. This lower guide member 5
3 is provided with a length substantially equal to that of the upper guide member 35, and a guide groove 53G is formed on the upper surface of the guide member 53 so as to guide the die holder 17 in the left and right directions.

Guide groove 53 in the guide member 53
Pistons 55P are provided at a plurality of locations on the bottom of G at appropriate intervals in the left-right direction, and the bottom surface of the die holder 17 is slightly attached to the cylinder block 55 that is vertically movably fitted to each piston 55P. A supporting roller 57 for pushing and supporting is rotatably attached.

On the front surface of the lower table 13,
A lower fixing device 59 for fixing the die holder 17 is attached. The lower fixing device 59 includes a piston 61P.
It comprises a cylinder block 61 in which is movably installed. A pressing lever 63 for pressing and fixing the die holder 17 to one side of the guide groove 53G of the guide member 53 by being pressed by the piston 61P is pivotally attached to the cylinder block 61 via a pin 65. .

With the above structure, the die holder 17 is fixed to the guide member 53 by supplying the working fluid to the cylinder block 61 in the lower fixing device 59.

With the above-described structure, the punch holder 15 and the die holder 17 can be moved in the left-right direction with respect to the upper and lower tables 11 and 13 of the press brake 1, and the punch holder 1 can be placed at a predetermined position on the upper and lower tables 11 and 13.
5, it will be understood that the die holder 17 can be fixedly supported.

The die exchanging device 7 for detaching and exchanging the punch holder 15 and the die holder 17 mounted on the upper and lower tables 11 and 13 of the press brake 1 can store the punch holder 15 and the die holder 17 as a pair. This is a mold accommodating device, and is configured as follows in this embodiment.

That is, the mold exchanging device 7 is shown in FIGS.
As shown in Fig. 6, a frame 6 made by assembling shaped steel into a square shape.
Equipped with 7. A guide beam 69 extending in the front-back direction (left-right direction in FIG. 2) is provided on the upper portion of the frame 67.
Is provided, and a guide rail 71 in the front-rear direction is provided on the lower surface of the guide beam 69.

A slider 73 is attached to the guide rail 71.
A movable rack 75 is movably supported in the front-rear direction via the. In addition, the movable rack 75 is attached to the guide rail 7
A moving positioning device 76 having a ball screw mechanism rotated by a servomotor (not shown) is provided on the frame 67 for moving and positioning along 1 in the front-back direction.

The movable rack 75 has a plurality of mold accommodating portions 77 arranged in parallel in the front-rear direction. More specifically, as shown in FIG. 6, the movable rack 75 includes an upper frame 79 in which shaped steels are combined in a grid pattern, and a plurality of support frames 81 are provided in the front-rear direction (see FIG. 6 are provided at appropriate intervals in the left-right direction, and the mold accommodating portion 77 is provided between the support frames 81.
Are formed.

Each of the die accommodating portions 77 has an opening on the lower side, and a plurality of supporting rollers 83 for movably supporting the inclined surface 15F of the punch holder 15 are provided on the upper portion of the die accommodating portions 77. There is provided an upper holder support portion 85 having Further, a plurality of support rollers 87 for supporting the die holder 17 are provided on the lower side of the die accommodating portion 77 on the front and rear surfaces of each of the support frames 81 to provide a lower holder supporting portion 89 for supporting the die holder 17. Has been.

In order to fix the punch holder 15 supported by the upper holder supporting portion 85 in the die accommodating portion 77, the upper frame 7 in the movable rack 75 is fixed.
A bracket 91 extending in the front-rear direction is attached to the upper part of 9, and each of the mold accommodating parts 77 is attached to the bracket 91.
Corresponding to the above, a plurality of fixed cylinders 93 are attached.

As shown in FIG. 7, a groove-shaped restricting member 95 for restricting movement of the punch holder 15 and an upper surface of the punch holder 15 are provided below the piston rod 93R provided on the fixed cylinder 93 so as to be vertically movable. Formed engagement hole 1
A locking pin 97 that can be engaged and disengaged is attached to 5H.

Therefore, the cylinder 93 is operated and the punch holder 15 is regulated by the regulating member 95,
Further, by engaging the locking pin 97 with the engagement hole 15H, the punch holder 15 supported by the upper holder support portion 85 can be fixed in an immovable state.

In order to fix the die holder 17 supported by the lower holder support portion 89, shot pin cylinders 99 are attached to the end portions of the support frames 81, respectively. A shot pin (not shown) is provided in an engagement hole (not shown) provided in the die holder 17 so as to be freely engageable and disengageable.

Therefore, by engaging the shot pins of the shot pin cylinders 99 with the engagement holes of the die holder 17, the die holders 17 are fixed to the lower holder support portions 89.

As already understood, the movable rack 7
Since the upper and lower holder support portions 85 and 89 are provided separately in the respective mold accommodating portions 77 in FIG. 5, the punch 3 and the die 3 corresponding to the upper and lower sides and pre-centered are provided. The punch holder 15 and the die holder 17 supporting 5 can be housed in the same mold housing 77 at the same time and can be carried out at the same time.

Further, since the plurality of mold accommodating portions 77 are arranged side by side in the front-rear direction, and the movable rack 75 is moved in the front-rear direction, and is not vertically inverted, the inside of each mold accommodating portion 77 is not changed. Punch 3, die 5 as a pair stored in
The support structure of is simplified.

The upper and lower tables 11 and 13 of the press brake 1 and the mold accommodating portions 7 of the movable rack 75.
7 for exchanging the die (replacement of the punch holder 15 and the die holder 17) with the die 7.
The punch holder 15 and the die holder 17 are moved from the upper and lower tables 11 and 13 of the press brake 1 to the movable rack 75.
There is provided a holder loading / unloading device 101 that can be simultaneously drawn into the mold housing 77 and that can simultaneously push out the punch holder 15 and the die holder 17 in the mold housing 77 to the upper and lower tables 11 and 13.

More specifically, as shown in FIG. 1 and FIG.
The frame 67 of the mold exchanging device 7 is provided with a support beam 103 extending in the left-right direction.
Left and right ends of a ball screw 107 extending in the left-right direction are rotatably supported by bearings 105 provided at both left and right ends of the ball.

The ball screw 107 is rotated by a servo motor (not shown), and the nut member 109 movably screwed into the ball screw 107 is
An inverted L-shaped arm 111 whose tip extends in the direction of the press brake 1 is provided upright. And this arm 1
Above and below the tip of 11 are brackets 113, 1 attached to the ends of the punch holder 15 and die holder 17.
A punch holder clamp 117 and a die holder clamp 119 that can hold 15 are attached.

The punch holder clamp 117 and the die holder clamp 119 are provided on the brackets 113 and 11 respectively.
It suffices to be able to grip and release 5 and, for example, the configuration of a normal robot hand may be adopted, and therefore the description of the details of both clamps 117 and 119 will be omitted.

In the above structure, in order to attach / detach the punch 3 and the die 5 to / from the upper and lower tables 11 and 13 of the press brake 1, first, the punch holder 15 and the die holder 17 are attached to the upper table 11 and the lower table. Positioned at a predetermined position of 13, the upper and lower fixing devices 4
Fix with 9 and 59 respectively.

Then, the punch holder 15 and the die holder 1
7, the punch 3 and the die 5 corresponding to 7 are attached, and the movable table is moved up and down to engage the punch 3 and the die 5, and the punch 3 and the die 5 are centered. The die 5 is fixed to the punch holder 15 and the die holder 17.

After centering the punch 3 and the die 5 as described above, the bracket 113 provided in the punch holder 15 and the bracket provided in the die holder 17 by the punch holder clamp 117 and the die holder clamp 119 in the holder loading / unloading device 101. Hold 115.

Then, after the punch holder 15 and the die holder 17 are released from fixing, the ball screw 107 is driven to move the movable rack 75 to the upper and lower tables 11 and 13.
The punch holder 15 and the die holder 17 are drawn into the upper and lower holder supporting portions 85 and 89 of the mold accommodating portion 77 positioned at the side of the mold exchanging position, and the fixed cylinder 93 and the shot pin cylinder 99 are operated. , Punch holder 1
5 and the die holder 17 are fixed.

The pair of punch holders 15 and die holders 17 holding the punches 3 and the die 5 in the centered state by performing the above-described operation are housed in the respective mold housing portions 77 of the movable rack 75. . Therefore, the die accommodating portion 77 is prepared and accommodated as a pair of the punch 3, which is centered in advance, the punch holder 15, which holds the die 5, and the die holder 17.

As described above, when the punch holder 15 and the die holder 17 are stored in the respective mold accommodating portions 77 of the movable rack 75 and when the movable rack 75 is moved in the front-rear direction, a desired mold accommodating portion 77 is obtained. Is positioned at a mold replacement position corresponding to the upper and lower tables 11 and 13 of the press brake 1.

Then, the punch holder clamp 117 and the die holder clamp 11 in the holder loading / unloading device 101.
9, the brackets 113 and 115 are clamped, the punch holder 15 and the die holder 17 forming a pair are simultaneously pushed to predetermined positions of the upper and lower tables 11 and 13 of the press brake 1, and fixed by the upper and lower fixing devices 49 and 59. Thus, the punch holder 15 and the die holder 17 are mounted on the upper and lower tables 11 and 13.

As described above, when the punch holder 15 and the die holder 17 are fixed to the upper and lower tables 11 and 13 of the press brake 1 at predetermined positions, they are supported by the punch 3 supported by the punch holder 15 and the die holder 17. Since the die 5 is centered in advance, it is not necessary to center it again, and the work can be bent immediately.

Therefore, the punch 3 and the die 5 can be attached / detached to / from the press brake 1 in accordance with a program, and the machining can be continuously performed.

[0063]

As will be understood from the above description of the embodiments, according to the present invention, punches and dies which are pre-centered are provided in the respective die accommodating portions of the movable rack in the die exchanging apparatus. The punch holder and the die holder supporting the punch are housed as a pair, and the pair of the punch holder and the die holder are simultaneously attached to and detached from the upper and lower tables of the press brake. It is not necessary to re-center the punch and die each time the replacement is performed.

Therefore, according to the present invention, it is possible to sequentially attach and detach the punches and dies to and from the upper and lower tables in the press brake according to the program, and to successively perform the machining of the work according to the program. Labor saving by combining with etc.,
Unmanned can be easily achieved.

[Brief description of drawings]

FIG. 1 is a front view showing a device and a press brake according to the present invention.

FIG. 2 is a left side view of FIG.

FIG. 3 is a side sectional view of a part of a main part of the press brake.

FIG. 4 is a side sectional view of a part of a main part of the press brake.

FIG. 5 is a side sectional view of a part of a main part of the press brake.

FIG. 6 is a side view of a movable rack portion.

FIG. 7 is a side view showing an enlarged cross section of a part of the main part of FIG.

[Explanation of reference numerals] 1 press brake 3 punch 5 die 7 mold exchanging device 11 upper table 13 lower table 15 punch holder 17 die holder 75 movable rack 77 mold accommodating section 85 upper holder supporting section 89 lower holder supporting section 101 holder carrying in / out apparatus

Claims (4)

[Claims] 1. A mold replacement method for a press brake, comprising the following steps. (A) A step of mounting a punch in a punch holder that is longitudinally movable on a press brake and fixedly fixed at a predetermined position, and (b) is longitudinally movable and at a predetermined position on a lower table in the press brake. A step of attaching a die corresponding to the punch to a die holder that is fixedly attached; (c) moving one table in the press brake up and down to engage the punch and the die to form a pair of the punch and the die; Centering process,
(D) A punch after centering, a punch holder holding a die, and a die holder as a pair are simultaneously placed in an appropriate same die accommodating portion of a movable rack in a die accommodating device arranged on the side of the press brake. A step of directly storing, (e) a plurality of pairs of punches and dies that have been pre-centered in the respective mold accommodating portions of the movable rack in the mold accommodating device according to the steps a, b, c, d The step of storing the punch holder and the die holder, (f) Positioning the desired mold storage part of the movable rack in the mold storage device at the mold replacement position at the lateral position of the upper and lower tables of the press brake, and performing centering in advance. The step of simultaneously sending the punch, the punch holder holding the die, and the die holder as a pair to the upper and lower tables. 2. The press brake according to claim 1, wherein the respective mold accommodating portions of the movable rack in the mold accommodating device are arranged side by side in the front-rear direction, and the moving direction of the movable rack is the front-rear direction. Mold replacement method in. 3. A mold storage device arranged at a lateral position of the press brake is provided with a movable rack provided with a plurality of mold storage units arranged side by side in the front-rear direction so as to be movable in the front-rear direction and centered in advance. The punch performed, the punch holder that holds the die as a pair, the upper holder support portion and the lower holder support portion that are freely supported by the die holder as a pair are provided in the mold accommodating portions so as to be spaced apart from each other in the vertical direction. A punch holder and a die holder supported by a table can be simultaneously drawn into an arbitrary die accommodating portion, and a pair of punch holder and die holder accommodated in the die accommodating portion positioned corresponding to the upper and lower tables can be provided. A mold exchanging device for a press brake, characterized in that a holder loading / unloading device that can simultaneously push out to the upper and lower tables is provided in a mold storing device. 4. A mold rack storage unit provided in a movable rack has a lower opening, and the holder loading / unloading device has a guide unit at a position below the movable rack, and includes a pair of punch holders and die holders. The mold exchanging device for a press brake according to claim 3, further comprising a holder clasp that is capable of gripping one end side.