Workpiece holding die in panel bender

Abstract

The present invention provides a clamping die for a panel bender that is less likely to interfere with the rising portion of the workpiece (W) being clamped, and that is less likely to cause cosmetic defects in the workpiece (W). [Solution] The pressing die (1) in the panel bender (91) has a support column (11) that extends downward while attached to the upper frame (912) of the panel bender (91), and a pressing portion (12) provided at the lower end (11a) of the support column (11). The pressing portion (12) has an extended leg portion (122) that, when viewed from above, protrudes from the support column (11) in a first direction and in a first direction in a second direction perpendicular to the first direction. The extended leg portion (122) includes a straight first edge portion (122c) extending in the first direction as part of its outer shape, and has a bending stiffness reducing portion (M) that reduces the bending stiffness of the second corner portion (P2), which is the corner of the first edge portion (122c) opposite to the first direction in the first direction.

Description

Technical Field

[0005] , ,

[0001] The present invention relates to a work holding die in a panel bender.

Background Art

[0002] As described in Patent Document 1, a panel bender for bending sheet metal sandwiches and fixes a work between an upper top die and a lower bottom die, and performs a forward bending or reverse bending process by bringing a bending die into contact with and moving it relative to a free edge portion extending from the fixed portion.

[0003] The top die is a movable type in which a predetermined number of work holding dies are assembled and fixed to an upper frame so as to have a length corresponding to the bending length of the work. The movement of the work holding die is performed by an automatic die changer called an ATC provided in the panel bender.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] [[ID=3█]] As described in Patent Document 1, conventional workpiece holding dies have a symmetrical shape with a die positioned on the left and a die positioned on the right relative to the center in the left-right direction, when the direction in which the bending line extends is defined as the left-right direction. Specifically, the position of the support column, which is the center of the holding die in the vertical direction, is shifted inward in the left-right direction and forward in the front-back direction. As a result, the outer surface of the holding die in the left-right direction is scooped inward when viewed from the front. This is to avoid interference with flanges, such as 180° return flanges, that are raised on the left and right side edges of the workpiece held by the holding die during bending, if such flanges are present in previous processes.

[0006] In conventional workpiece clamping die shapes, when bending the free edge of a workpiece while it is clamped, the amount of deformation of the edge in response to the bending force applied from the workpiece differs significantly between the left and right corners. In other words, the amount of deformation on the side with the displaced support column, which has higher bending rigidity, is significantly smaller.

[0007] Therefore, when a workpiece is held down by an assembly of clamping dies, shear force is generated at the boundary between one clamping die and an adjacent clamping die, which can result in cosmetic defects such as the formation of grooves or other marks. For this reason, it is desirable that the workpiece clamping dies in panel benders are less likely to interfere with the raised portion of the workpiece being held, and that they are less likely to cause cosmetic defects to the workpiece. [Means for solving the problem]

[0008] One embodiment of one or more of the present invention is a panel bender press die having a support portion 11 extending downward when attached to the upper frame 912 of a panel bender 91, and a press portion 12 provided at the lower end of the support portion 11, wherein the press portion 12 has an extended leg portion 122 that, when viewed from above, protrudes from the support portion 11 in a first direction in the first direction and in a first direction in a second direction perpendicular to the first direction, and the extended leg portion 122 includes a linear first edge portion 122c extending in the first direction as part of its outer shape, and has a bending stiffness reducing portion M that reduces the bending stiffness of a second corner portion P2 which is a corner portion of the first edge portion 122c facing the opposite direction to the first direction. [Effects of the Invention]

[0009] According to the workpiece holding die in the panel bender according to one or more embodiments, the effects of less interference with the raised portion of the workpiece being held and less likely to cause cosmetic defects in the workpiece can be obtained. [Brief explanation of the drawing]

[0010] [Figure 1A] Figure 1A is a perspective view of a panel bender 91 equipped with a retaining die 1 according to one embodiment of the present invention. [Figure 1B] Figure 1B is a partially enlarged right side view illustrating the process of bending a workpiece W while holding it down with a holding die 1. [Figure 2] Figure 2 is a perspective view illustrating the retaining die 1. [Figure 3A] Figure 3A is a first perspective view of the pressing portion 12 of the pressing die 1. [Figure 3B] Figure 3B is a second perspective view of the retaining portion 12. [Figure 3C] Figure 3C is a rear view of the retaining portion 12. [Figure 4] Figure 4 is a perspective view showing the simulation results of the deflection distribution in the clamping portion 12. [Figure 5]Figure 5 is a perspective view showing the simulation results of the deflection distribution in the clamping portion 12E of the comparative example. [Figure 6A] Figure 6A is a diagram illustrating the clamping die assembly 1S, where Figure 6A(a) is a rear view, Figure 6A(b) shows the deflection characteristic line Lm, and Figure 6A(c) shows the surface of the workpiece W held by the clamping die assembly 1S. [Figure 6B] Figure 6B is a diagram illustrating the comparative example clamping die assembly 1ES, where Figure 6B(a) is a rear view, Figure 6B(b) shows the deflection characteristic line LmE, and Figure 6B(c) shows the surface of the workpiece W held by the clamping die assembly 1ES. [Figure 7A] Figure 7A is a perspective view showing the presser portion 12B of modified example 1 of the presser portion 12. [Figure 7B] Figure 7B is a perspective view showing the presser portion 12C, which is a modified example of the presser portion 12. [Figure 7C] Figure 7C is a rear view showing the presser portion 12D of modified example 3 of the presser portion 12. [Modes for carrying out the invention]

[0011] The configuration of a presser die 1, which is one embodiment of a workpiece presser die in a panel bender according to one or more embodiments of the present invention, will be described with reference to Figures 1A to 3C.

[0012] Figure 1A is a perspective view of a panel bender 91 equipped with a clamping die 1 according to one embodiment of the present invention. Figure 1B is a partially enlarged right side view illustrating the state in which bending is performed while pressing a workpiece W with the clamping die 1. Figure 2 is a perspective view illustrating the clamping die 1. Figure 3A is a first perspective view of the clamping portion 12 provided on the clamping die 1. Figure 3B is a second perspective view of the clamping portion 12. Figure 3C is a rear view of the clamping portion 12. In the following description, for convenience, the up, down, left, right, front, and back directions are defined in the direction of the arrows shown in Figure 1A.

[0013] As shown in FIG. 1A, the panel bender 91 includes a table portion 911, a holding die assembly 1S, an upper frame 912, and an automatic die changer 913. The automatic die changer 913 is commonly referred to as an ATC.

[0014] The upper frame 912 is disposed above the table portion 911 in a posture extending in the left - right direction, and approaches and separates from the table portion 911 in the vertical direction. As shown in FIGS. 1A and 2, a holding die 1 is detachably engaged by a mounting / demounting device 9131 provided in the automatic die changer 913 and is attached to the upper frame 912 so as to be movable in the left - right direction. The holding die 1 has a left - right asymmetric shape, and includes a left - hand holding die 1L and a right - hand holding die 1R.

[0015] On the table portion 911, a plurality of holding dies 1L are arranged on the left side of a center line C which is at the center position in the left - right direction, and a plurality of holding dies 1R are respectively arranged on the right side. The automatic die changer 913 automatically collects the desired number of holding dies 1L and holding dies 1R to the center side respectively so as to correspond to the width and processing position in the left - right direction of the next workpiece to be processed, and automatically forms a left assembly 1SL and a right assembly 1SR. The holding die assembly 1S is composed of the left assembly 1SL and the right assembly 1SR.

[0016] In FIG. 1A, 10 holding dies 1L and 10 holding dies 1R are respectively mounted on the upper frame 912. Among them, a holding die assembly 1S in which a total of 18 holding dies 1, 9 of each type, are assembled is constructed and shown in a state prepared for the next bending process. The number of holding dies 1L and holding dies 1R does not necessarily have to be the same. Also, the number of each die can be changed.

[0017] As shown in FIG. 1B, below the holding die 1, a receiving die 2 is fixed to the table portion 911 at a position facing the holding die 1. Also, behind the holding die 1 and the receiving die 2, a bending die 3 that moves in the vertical direction is arranged.

[0018] With this configuration, when bending the bent portion Wf of a sheet metal workpiece W, first, the clamping die 1 is moved upward. Next, from the front of the panel bender 91, an operator or robot inserts the workpiece W in a horizontal position into the gap between the clamping die 1 and the receiving die 2. The inserted workpiece W has its bending position Pb, which is the base position of the bent portion Wf, at the rear edge of the clamping die 1, and in this state, the clamping die 1 is lowered to clamp the workpiece W. Next, the bending portion Wf is pushed up by the bending die 3 (see arrow DR1), and bent with the bending position Pb as the fulcrum.

[0019] Next, the detailed configuration of the clamping die 1, which works in cooperation with the receiving die 2 to hold the workpiece W as described above, will be explained. As shown in Figure 2, the clamping die 1 has a base portion 10, a support portion 11, a clamping portion 12, and a connecting plate 13. This clamping die 1 is the clamping die 1L located to the left of the center line C in Figure 1A. When distinguishing between the left and right sides of the clamping portion 12 of the clamping dies 1L and 1R on the left and right sides of the center line C, they are distinguished as clamping portion 12L and clamping portion 12R (see Figure 1A).

[0020] The base portion 10 of the retaining die 1 is a part that is detachably attached to the upper frame 912 by a mounting / detaching device 9131. When the retaining die 1 is attached to the upper frame 912, the support column portion 11 is a rectangular prism-shaped part that extends downward from the lower part of the base portion 10 with a rectangular cross-section. The end face of the lower end portion 11a of the support column portion 11 is a horizontal plane. The retaining portion 12 is fastened and fixed to the lower end portion 11a of the support column portion 11 by screwing in bolts 14 using a connecting plate 13 that spans the support column portion 11 and the retaining portion 12, and by screwing in multiple bolts (not shown) from below. In Figure 2, the retaining portion 12 is shaped to extend to the left and rearward relative to the support column portion 11.

[0021] As shown in Figures 3A to 3C, the retaining portion 12 has a base portion 121 and an extension leg portion 122. The base portion 121 is formed in the same shape as the end face of the lower end portion 11a of the support portion 11 and has an upper end portion 121a that is in close contact with the lower end portion 11a. The base portion 121 has a female threaded portion 121b formed on its front surface, into which a bolt 14 for fastening the connecting plate 13 is screwed. The extension leg portion 122 is a part that extends outwards to the left and rear from a position slightly below the upper end portion 121a of the base portion 121. The shape of the extension leg portion 122 when viewed from above is rectangular. More specifically, the extended leg portion 122 of the retaining portion 12, when viewed from above, has a straight first edge portion 122c extending in a first direction (left-right direction) as part of its outer shape, which protrudes from the support portion 11 in a first direction (leftward) and a second direction (front-back direction) perpendicular to the first direction.

[0022] In an overhead view, the retaining portion 12L has its base portion 121 positioned to the front right, with its right end being the right side surface 12a that extends in the front-rear and up-down directions, straddling both the base portion 121 and the extension leg portion 122. On the other hand, in this example, the retaining portion 12R has a symmetrical shape with respect to the retaining portion 12L, but it does not necessarily have to be symmetrical.

[0023] The extension leg portion 122 has a first inclined portion 122a, a second inclined portion 122b, and a recessed portion M. The first inclined portion 122a is the portion that connects to the base portion 121 and slopes downward with respect to the horizontal at a first inclination angle θa (see Figure 3C). The second inclined portion 122b connects to the lower edge of the first inclined portion 122a and slopes downward with respect to the horizontal at a second inclination angle θb (see Figure 3C), which is greater than the first inclination angle θa, and connects to the edge of the rectangle. The boundary between the first inclined portion 122a and the second inclined portion 122b is an upwardly convex ridge line LN12 because the second inclination angle θb is greater than the first inclination angle θa. The ridge line LN12 is horizontal when viewed from the left and in the rear view in Figure 3C. Furthermore, as shown in Figures 3B and 3C, the base portion 121 is formed asymmetrically in an upward view so as to include the center line CL12 that extends vertically and is located at the center of the extension leg portion 122 in the left-right and front-back directions.

[0024] As shown in Figures 3B and 3C, the recessed portion M is formed on the rear side of the base portion 121 such that a portion of the right side surface 12a, the first inclined portion 122a, and the second inclined portion 122b are recessed. The recessed portion M is formed having a first recessed inclined portion Ma, a second recessed inclined portion Mb, and a recessed wall portion Mc. The first recessed inclined portion Ma is located in the height region included in the first inclined portion 122a in the vertical direction and is the portion that is inclined with respect to the horizontal at a third inclination angle θc in Figure 3C, which is a rear view. The second recessed inclined portion Mb is located in the same height region as the second inclined portion 122b in the vertical direction and is the portion that is inclined with respect to the horizontal at a fourth inclination angle θd which is greater than the third inclination angle θc. The ridge line LNM, which is the boundary line between the first recessed inclined section Ma and the second recessed inclined section Mb, is formed to be horizontal when viewed from the right at the same height as the ridge line LN12. The recessed wall section Mc is formed at position Pm in the front-rear direction on the rear side of the base section 121, extending in the up-down and left-right directions and connecting to the first recessed inclined section Ma and the second recessed inclined section Mb.

[0025] The retaining portion 12 (12L, 12R) has a recessed portion M, which significantly reduces the bending rigidity near the right rear corner P2 of the extended leg portion 122 compared to the case where the recessed portion M is not formed. This reduction in bending rigidity will be specifically explained for the retaining portion 12L with reference to the simulation results in Figures 4 and 5.

[0026] The simulation was performed on the aforementioned pressing portion 12 provided in one embodiment of the pressing die 1, and on a comparative example pressing portion 12E, which has the shape of pressing portion 12 with the notched portion M removed. Specifically, first, the pressing portion 12 and pressing portion 12E were assumed to be in a state where the workpiece W was sandwiched between the workpiece W and the receiving die 2 as shown in Figure 1B. Then, when the bending die 3 bent the bent portion Wf of the workpiece W upward, the amount of upward elastic deformation of the left rear corner P1 and right rear corner P2 of the pressing portion 12, and the left rear corner PE1 and right rear corner PE2 of the pressing portion 12E was determined under the same conditions for both the pressing portion 12 and the pressing portion 12E. In the distribution of deformation amount, less than 0.1 mm was shown in white (no indication), 0.1 mm or more and less than 0.15 mm was designated as the first region AR1 (indicated by coarse hatching), and 0.15 mm or more was designated as the second region AR2 (indicated by dense hatching). The simulation results for the clamping portion 12 are shown in Figure 4, and the simulation results for the clamping portion 12E are shown in Figure 5.

[0027] As a result, no significant difference was observed between the distribution of the first region AR1 and the second region AR2 of the clamping portion 12E of the comparative example shown in Figure 5 and the distribution of the first region AR1 and the second region AR2 of the clamping portion 12 of the embodiment shown in Figure 4 for the left rear corner P1 and PE1. On the other hand, for the right rear corner P2 and PE2, the second region AR2, which was not observed near the right rear corner PE2 of the clamping portion 12E of the comparative example, was clearly observed near the right rear corner P2 of the clamping portion 12 of the embodiment. In other words, it became clear that the area near the right rear corner P2 of the clamping portion 12 is significantly more prone to bending in response to the same magnitude of force applied in the vertical direction than the area near the right rear corner PE2 of the clamping portion 12E of the comparative example.

[0028] Specifically, the deformation amounts β1 and β2 of the left rear corner PE1 and the right rear corner PE2 in the comparative example's pressing portion 12E, and their absolute difference ΔdE were as follows. (Comparative example: pressing part 12E) Left rear corner PE1 (β1): 0.249mm Right rear corner PE2 (β2): 0.121mm ΔdE: 0.128 mm

[0029] The deformation amounts α1 and α2 of the left rear corner P1 and the right rear corner P2 of the pressing portion 12 in the embodiment, and their absolute difference Δd, were as follows. (Example - Pressing part 12) Left rear corner P1 (α1): 0.239mm Right rear corner P2 (α2): 0.180mm Δd: 0.059 mm

[0030] This revealed that the absolute difference between the deformation amount α1 of the left rear corner P1 in the presser portion 12 of the embodiment and the deformation amount β1 of the left rear corner PE2 in the presser portion 12E of the comparative example was 0.01 mm, indicating that the difference was slight and they were almost the same. On the other hand, the absolute difference between the deformation amount α2 of the right rear corner P2 in the presser portion 12 of the embodiment and the deformation amount β2 of the right rear corner PE2 in the presser portion 12E of the comparative example was 0.059 mm, indicating that the deformation amount α2 of the presser portion 12 was larger.

[0031] Furthermore, it was revealed that the absolute difference Δd in the pressing portion 12 of the embodiment was less than half of the absolute difference ΔdE in the pressing portion 12E of the comparative example, confirming that the recessed portion M functions as a bending stiffness reduction portion that significantly reduces the bending stiffness near the right rear corner P2 of the extended leg portion 122.

[0032] Thus, by having a recessed portion M, the clamping portion 12 reduces the difference in bending rigidity between the area near the left rear corner P1 and the area near the right rear corner P2. Therefore, the amount of bending deformation of the clamping portion 12 when bending the workpiece W with the panel bender 91 is as follows. That is, when the clamping dies 1 are assembled to form a clamping die assembly 1S (see Figure 6A(a)), and the workpiece W is placed between it and the receiving die 2 (see Figure 1B) and the bending process is performed, the absolute difference Δd between the amount of bending deformation α2 of the right rear corner P2 of the clamping portion 12 of the first clamping die 1 and the amount of bending deformation α1 of the left rear corner P1 of the second clamping die 1 adjacent to the right becomes small (see Figure 6A(b)).

[0033] In other words, the shear force applied to the workpiece W at the boundary position Pk between the first clamping die 1 and the adjacent second clamping die 1 is small. Therefore, the workpiece W, which has been bent while sandwiched between the receiving die 2, does not have any visible defects such as grooves at the boundary position Pk, or at least it is extremely difficult for such marks to be formed [see Figure 6A(c)].

[0034] In contrast, when bending is performed using a presser die assembly 1ES, which is formed by assembling presser dies 1E equipped with a comparative example presser portion 12E without a notched portion M as shown in Figure 6B(a), instead of the presser die assembly 1S, the amount of bending deformation of the presser portion 12E is as follows. That is, the absolute difference ΔdE between the amount of bending deformation β2 of the right rear corner PE2 of the presser portion 12E of the first presser die 1E and the amount of bending deformation β1 of the left rear corner PE1 of the second presser die 1E adjacent to the right is significantly larger than the absolute difference Δd, as previously described [see Figure 6B(b)]. Therefore, when bending is performed with the workpiece W sandwiched between the presser die assembly 1ES and the receiving die 2 (see Figure 1B), the shear force applied to the workpiece W at the boundary position PEk between the first presser die 1E and the adjacent second presser die 1E is very large. Therefore, the workpiece W, which has been bent while sandwiched between the receiving die 2, may develop marks such as grooves Lf at the boundary position PEk, which may result in cosmetic defects [see Figure 6B(c)].

[0035] As described above, the pressing die 1 equipped with the pressing portion 12 has the effect of being less likely to interfere with the flange of the workpiece W being pressed, and less likely to cause cosmetic defects in the workpiece W.

[0036] One aspect of the present invention is not limited to the configuration and procedure described above, and may be modified without departing from the spirit of the invention.

[0037] The shape of the notched portion M, which is a bending stiffness reducing portion of the pressing portion 12, can be freely deformed as long as it reduces the bending stiffness near the right rear corner P2. That is, the notched portion M may be, for example, the notched portion MB of the pressing portion 12B in Modification 1 shown in Figure 7A, or the notched portion MC of the pressing portion 12C in Modification 2 shown in Figure 7B. The notched portion MB is an example in which the notch width in the front-rear direction is smaller than that of the notched portion M, and the notched portion MC is an example in which the notch length in the left-right direction is shorter than that of the notched portion M. In both the pressing portion 12B and the pressing portion 12C, the bending stiffness near the right rear corner P2 is reduced, so the amount of bending deformation of the right rear corner P2 is increased and the difference with the amount of bending deformation of the left rear corner P1 is reduced. As a result, the pressing portion 12B and the pressing portion 12C can obtain the same effect as the pressing portion 12.

[0038] Furthermore, the retaining portion 12 has an extended leg portion 122 which has a first inclined portion 122a and a second inclined portion 122b to form an upwardly convex ridge line LN12. However, the first inclined portion 122a and the second inclined portion 122b may be set so that their respective inclination angles form a downwardly concave valley line. Also, the retaining portion 12 may be modified to have a recessed portion MD as shown in Figure 7C, and an extended leg portion 122D which has the same inclination angles for the first inclined portion 122a and the second inclined portion 122b and no ridge line LN12 or valley line at the boundary, as shown in Modification 3 of the retaining portion 12D. It may also have three or more inclined portions with different inclination angles so that multiple ridge lines or valley lines are generated. Furthermore, each inclined surface may be formed not only as a flat surface but also as a curved surface or including a curved surface.

[0039] In all of these modifications, as long as the recessed portion M is present, the effect is obtained that interference with the flange of the workpiece W being held during bending is less likely to occur, and cosmetic defects are less likely to occur in the workpiece.

[0040] The retaining portion 12 is not limited to being detachably attached to the support portion 11 as described above, but may also be integrally attached to the lower end portion 11a of the support portion 11.

[0041] As described in detail above, the first aspect of one or more embodiments of the present invention is a press die for a panel bender having a support column 11 that extends downward when attached to the upper frame 912 of a panel bender 91, and a pressing portion 12 provided at the lower end 11a of the support column 11, wherein the pressing portion 12 has an extended leg portion 122 that, when viewed from above, protrudes from the support column 11 in a first direction in the first direction and in a first direction in a second direction perpendicular to the first direction, and the extended leg portion 122 includes a linear first edge portion 122c extending in the first direction as part of its outer shape, and has a bending stiffness reducing portion M that reduces the bending stiffness of a second corner portion P2 which is a corner portion of the first edge portion 122c that is in the opposite direction to the first direction in the first direction.

[0042] According to this first embodiment, interference with the rising portion of the workpiece W being held is less likely, and cosmetic defects are less likely to occur in the workpiece W.

[0043] In the first embodiment, when attached to the upper frame 912, the extension leg portion 122 may have an inclined portion 122a that slopes downward from the support portion 11 toward the first edge portion 122c.

[0044] This clarifies the differences in the effect of reducing bending stiffness depending on the shape of the bending stiffness reduction section M, making it possible to obtain a more optimal shape for the bending stiffness reduction section M.

[0045] In the first embodiment, the bending rigidity reduction portion M may be a recess.

[0046] This makes it easier to manufacture the retaining die 1.

[0047] The bending stiffness reducing portion M of the first embodiment reduces the difference between the bending stiffness of the first corner portion, which is the corner portion of the first edge portion in the first orientation, and the bending stiffness of the second corner portion.

[0048] This makes it less likely for the workpiece W to develop cosmetic defects. [Explanation of symbols]

[0049] 1,1L,1R,1E retaining die 1S, 1ES Pressing die assembly 1SL left aggregate 1SR Right aggregate 10 base 11 Support section 11a Lower end 12, 12L, 12R, 12B, 12C, 12D, 12E Retaining part 12a Right side 121 Base 121a Upper end 121b Female thread section 122,122D Extension Legs 122a 1st slope part 122b 2nd slope 122c 1st edge 13 Connecting Plates 14 volts 2. Receiving mold 3 Bending die 91 Panel Vendor 911 Table section 912 Upper frame 913 Automatic Die Changer (ATC) 9131 Loading / unloading device AR1 1st area AR2 2nd area C,CL12 Center line Lf streaks Lm deflection characteristic curve LN12,LNM ridgeline M, MB, MC, MD: Recessed section (section with reduced bending rigidity) Ma First gouged inclined section Mb Second indented slope Mc gouged wall section Pb folding position Pk,PEk boundary position Pm position P1,PE1 Left posterior corner P2,PE2 Right rear corner W Work (Sheet Metal) Wf folding section θa First inclination angle θb Second tilt angle θc Third inclination angle θd The fourth inclination angle α1, α2, β1, β2 deformation amount Δd, ΔdE absolute difference

Claims

1. It has a support column that extends downward while attached to the upper frame of the panel bender, and a retaining portion provided at the lower end of the support column, The retaining portion has, when viewed from above, an extended leg portion that protrudes from the support column portion in a first direction in a first direction and in a first direction in a second direction perpendicular to the first direction, The aforementioned extension leg portion is A clamping die for a panel bender, which includes a linear first edge portion extending in the first direction as part of its outer shape, and has a bending stiffness reducing portion that reduces the bending stiffness of a second corner portion which is a corner portion of the first edge portion facing the opposite direction to the first orientation in the first direction.

2. The press-fit die for a panel bender according to claim 1, wherein the extension leg portion, when attached to the upper frame, has an inclined portion that slopes downward from the support column portion toward the first edge portion.

3. The pressing die in the panel bender according to claim 1, wherein the bending rigidity reduction portion is a recess.

4. The clamping die for a panel bender according to any one of claims 1 to 3, wherein the bending stiffness reduction portion reduces the difference between the bending stiffness of the first corner portion, which is the corner portion of the first edge portion in the first orientation, and the bending stiffness of the second corner portion.

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