Explosion-proof bending device
By using an explosion-proof bending device to round the edges and corners of sheet metal parts, the problems of welding quality defects and stress concentration in traditional processes are solved, thus achieving stability and high-quality forming of sheet metal parts.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- SUZHOU DAWNWATCH MEDICAL EQUIP CO LTD
- Filing Date
- 2025-04-29
- Publication Date
- 2026-05-26
AI Technical Summary
Traditional sheet metal processing techniques result in welding quality defects, stress concentration, and microscopic material damage, leading to structural instability and an inability to provide explosion-proof protection.
An explosion-proof bending device is used to round the edges and corners of the sheet metal parts through the bending mechanism, and the excess is removed by the trimming mechanism to avoid welding and stress concentration, and to ensure that the metal grains are evenly extended.
It improves the sealing performance and overall structural stability of sheet metal parts, reduces the risk of stress concentration, avoids welding defects and material damage, and enhances molding quality.
Smart Images
Figure CN224272875U_ABST
Abstract
Description
Technical Field
[0001] This utility model belongs to the field of sheet metal processing technology, and in particular relates to an explosion-proof bending device. Background Technology
[0002] In sheet metal manufacturing, grooved structures are a common functional form, and traditional processing typically employs the following process chain: (e.g.) Figure 1 As shown, (1) the top corner of the sheet metal part is pre-cut; (2) the edge part is bent into shape using a bending machine; (3) the joint after bending is welded closed. This process has the following inherent defects:
[0003] 1. Welding quality defects
[0004] During the welding process, uneven heat input can easily lead to two typical failure modes: (1) coarsening of grains in the weld area to form a brittle phase, which in turn can lead to the initiation of microcracks; (2) welding deformation caused by residual stress can significantly reduce the structural dimensional accuracy. Actual test data show that the fatigue life of the welded parts is 40%-60% lower than that of the base material.
[0005] 2. Stress concentration effect
[0006] The right-angle transition structure formed by traditional processes can cause the stress line to change abruptly at the corner. Finite element analysis shows that when the sidewall angle is ≤90°, the local stress concentration factor (Kt) can reach 2.8-3.5, which becomes the preferred location for fatigue crack initiation.
[0007] 3. Microscopic damage to materials
[0008] Sharp edges in the stamping process of sheet metal parts can cause two levels of problems: (1) On a macro scale, necking cracks are likely to occur when the sheet metal thinning rate exceeds 20%; (2) On a micro scale, EBSD test shows that the grain orientation difference (KAM value) in the edge area is 57% higher than that in the planar area, and the increased dislocation density leads to abnormal recrystallization in subsequent heat treatment.
[0009] Therefore, traditional processing methods will lead to unstable structure of the formed sheet metal parts and failure to provide explosion protection. Designing an explosion-proof bending device is an important technical problem that needs to be solved by those skilled in the art. Utility Model Content
[0010] The purpose of this invention is to solve the above-mentioned problems in the prior art and to provide an explosion-proof bending device.
[0011] The objective of this utility model is achieved through the following technical solution:
[0012] An explosion-proof bending device is mounted on a base; it includes a bending mechanism and a trimming mechanism; the bending mechanism includes a positioning block mounted on the base and a forming component mounted above the positioning block; the forming component is mounted on a support, and the support is fixed to the upper surface of the base; the forming component includes a driving member mounted on the top surface of the support, and the end of the driving member penetrates the support and is fixed with a slider and a pressure plate; a forming upper die is provided inside the slider, and the pressure plate is located outside the forming upper die; the inner bottom surface of the sheet metal part is placed on the positioning block, and its four sides are in contact with the four walls of the positioning block; when the driving member is activated, the pressure plate abuts against the outer bottom surface of the sheet metal part, and the forming... The upper die applies force to the outer surface of the sheet metal part's corners, shaping the corners into rounded corners. A notch corresponding to the outer contour of the rounded corner sheet metal part is provided near the base. The trimming mechanism includes a trimming die disposed on the lower surface of the base, with a cutter corresponding to the inner contour of the rounded corner sheet metal part. A wedge-shaped groove matching the bottom end of the slider is formed on the trimming die. The driving member moves the slider downwards, penetrating the base until it inserts into the wedge-shaped groove. The slider drives the trimming die to move towards the pressure plate until the cutter abuts against the notch, thus removing the portion of the rounded corner sheet metal part protruding from its outer edge, completing the sheet metal bending process.
[0013] Preferably, the upper forming mold is hourglass-shaped, and the middle connection is transitioned by an arc; the corner of the positioning block is rounded and coaxial with the middle arc transition section of the upper forming mold.
[0014] Preferably, the upper forming mold is connected to the slider via a connecting shaft, and the connecting shaft is coaxially arranged with the upper forming mold so that it rises and falls synchronously with the slider.
[0015] Preferably, a fixed seat is provided on the side of the slider near the notch, and a telescopic member is provided on the fixed seat. The pressure plate is fixed to the bottom of the telescopic member. In the initial state, the pressure plate is lower than the connecting shaft and first abuts against the sheet metal part after the driving member is started, and then the telescopic member is gradually compressed.
[0016] Preferably, the bracket includes two vertically arranged first guide rails 9 and a cover plate 9 vertically fixed to the top of the first guide rails 9; the inner wall of the first guide rails 9 forms a guide groove for accommodating the slider; the driving member is fixed to the cover plate 9, and its driving end passes through the cover plate 9.
[0017] Preferably, the trimming mechanism further includes a second guide rail fixed to the lower surface of the base, the second guide rail being disposed on both sides of the trimming die, and the second guide rail having a groove for accommodating the trimming die; the trimming die moves relative to the second guide rail and the base; the upper surface of the trimming die is flush with the upper surface of the second guide rail.
[0018] Preferably, the trimming die has a through hole for accommodating a reset member. The reset member is an elastic member, with its two ends abutting against the hole wall of the trimming die and the mounting block, respectively. The mounting block is fixed to the lower surface of the base and located inside the through hole of the trimming die.
[0019] Preferably, both the trimming die and the base have through holes for accommodating the upper forming die.
[0020] Preferably, a connecting bridge is provided in the through hole on the trimming die, the connecting bridge is centrally located along the width direction of the trimming die, and a stop groove is formed on the connecting bridge for placing the middle connecting section of the upper forming die.
[0021] The advantages of this utility model's technical solution are mainly reflected in:
[0022] This utility model is based on the bending of the edges of sheet metal parts by ordinary bending machines, so that the corners of the sheet metal parts are warped but not broken. Then, the corners of the sheet metal parts after edge bending are bent. Since the sheet metal parts are one piece and do not need to be welded and fixed, their sealing performance and overall structure are relatively stable, which can play an explosion-proof role.
[0023] The corners of the sheet metal part are bent by the positioning block and the forming upper die in the bending mechanism. Since the positioning block and the forming upper die are both rounded, the stress lines are evenly distributed through smooth geometric changes, which significantly reduces the stress concentration factor. The rounded transition also helps the metal grains to extend naturally along the direction of force, avoiding grain breakage or misalignment. Furthermore, the rounded deformation is more uniform during cold working, which can reduce the risk of brittleness.
[0024] The excess part of the rounded corner sheet metal part after bending is cut by the edge cutting mechanism. Since the top surface of the edge cutting die is in contact with the bottom surface of the base, the edge of the sheet metal part is smooth and without burrs after being cut by the cutter, and the finished sheet metal part has high quality. Attached Figure Description
[0025] Figure 1 Background technology processing structure diagram of this utility model;
[0026] Figure 2 : Processing structure diagram of a preferred embodiment of this utility model;
[0027] Figure 3: A perspective view of a preferred embodiment of the present invention;
[0028] Figure 4 : A front view of the initial state of a preferred embodiment of this utility model;
[0029] Figure 5 : First cross-sectional view of the initial state of the preferred embodiment of this utility model;
[0030] Figure 6 : Second cross-sectional view of the initial state of the preferred embodiment of this utility model;
[0031] Figure 7 : A front view of the positioning state of a preferred embodiment of this utility model;
[0032] Figure 8 : First cross-sectional view of the positioning state of the preferred embodiment of this utility model;
[0033] Figure 9 : Second cross-sectional view of the positioning state of the preferred embodiment of this utility model;
[0034] Figure 10 : A front view of the preferred embodiment of this utility model in the bent state;
[0035] Figure 11 : First cross-sectional view of the preferred embodiment of this utility model in the bent state;
[0036] Figure 12 : Second cross-sectional view of the preferred embodiment of this utility model in the bent state;
[0037] Figure 13 : A front view of the cutting state of a preferred embodiment of this utility model;
[0038] Figure 14 : First cross-sectional view of the preferred embodiment of this utility model in the cutting state;
[0039] Figure 15 : Second cross-sectional view of the preferred embodiment of this utility model in the cutting state. Detailed Implementation
[0040] The purpose, advantages, and features of this utility model will be illustrated and explained through the following non-limiting description of preferred embodiments. These embodiments are merely typical examples of applying the technical solutions of this utility model, and all technical solutions formed by equivalent substitutions or equivalent transformations fall within the scope of protection claimed by this utility model.
[0041] In the description of the solution, it should be noted that the terms "center," "upper," "lower," "left," "right," "front," "rear," "vertical," "horizontal," "inner," and "outer," etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings and are only for the convenience and simplification of description. They do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance. Also, in the description of the solution, with the operator as a reference, the direction closer to the operator is the proximal end, and the direction farther from the operator is the distal end.
[0042] like Figure 2 This is a structural diagram of the sheet metal part processed according to this utility model. This utility model is based on the edge bending of sheet metal parts using a common bending machine, so that the corners of the sheet metal parts are warped but not broken. Then, the corners of the edge-bent sheet metal parts are further bent. Since the sheet metal parts are one-piece and do not require welding for fixation, their sealing performance and overall structure are relatively stable, which can play a role in explosion protection.
[0043] The bending process of this sheet metal part is as follows: Figures 3 to 15 The diagram illustrates an explosion-proof bending device. Specifically, the bending device is mounted on a base 3, which is equipped with a positioning block 11 and a forming component 12.
[0044] like Figure 3 As shown, the explosion-proof bending device disclosed in this utility model specifically includes at least a bending mechanism 1. The bending mechanism 1 bends the edges and corners of the sheet metal part, resulting in a rounded corner transition to avoid stress concentration and microscopic damage to the material. Specifically, the rounded corner transition, through smooth geometric changes, ensures a uniform distribution of stress lines, significantly reducing the stress concentration factor. Furthermore, the stress concentration factor can be reduced by increasing the radius of the rounded corner, which can be adjusted as needed and is not limited here. In addition, the rounded corner transition helps the metal grains extend naturally along the direction of force, preventing grain breakage or misalignment; and during subsequent cold working, the rounded corner deformation is more uniform, reducing the risk of brittleness.
[0045] Furthermore, the bending mechanism 1 includes a positioning block 11 disposed on the base 3 and a forming component 12 disposed above the positioning block 11. The positioning block 11 has at least one rounded corner, which abuts against the corner of the sheet metal part to be processed, thereby forming the sheet metal part into a rounded-corner bent part. Preferably, the positioning block 11 in this invention is angular, and each corner is rounded. Furthermore, the rounded corners on the positioning block 11 can be designed with different radii to adapt to different bending requirements.
[0046] The molding component 12 is mounted on the bracket 31, and the bracket 31 is fixed to the upper surface of the base 3. The bracket 31 includes two vertically arranged first guide rails 311 and a cover plate 312 vertically fixed to the top of the first guide rails 311. The inner wall of the first guide rails 311 is formed as shown in the image. Figure 5 , Figure 8 , Figure 11 and Figure 14 The guide groove shown is used to accommodate the slider 122 in the molding assembly 12; that is, the slider 122 is located within the first guide rail 311 and moves along the setting direction of the guide rail 311 during use. The guide rail 311 effectively limits the movement direction of the slider 122 and reduces the wobbling of the slider 122 during movement, improving operational stability. Furthermore, to reduce the friction between the slider 122 and the first guide rail 311, a pulley can be provided between the slider 122 and the first guide rail 311, making the movement of the slider 122 smoother without changing the movement direction, thereby improving processing efficiency and reducing equipment damage.
[0047] The molding component 12 includes a driving member 121 disposed on the top surface of the bracket 31. The driving member 121 is fixed to the cover plate 312, and its driving end penetrates through the cover plate 312. That is, the end of the driving member 121 penetrates through the bracket 31. In this utility model, the driving member 121 is preferably a hydraulic cylinder or oil cylinder. In other embodiments, the driving member 121 can also be a linear module or an electric cylinder or other known structures, which are not limited here.
[0048] Combination Figure 3 and Figure 6 , Figure 9 , Figure 12 and Figure 15 As shown, a slider 122 and a pressure plate 13 are fixed to the end of the driving component 121. A forming upper die 14 is disposed inside the slider 122. Furthermore, the forming upper die 14 is hourglass-shaped, meaning it is smaller in the middle and larger at both ends, with a rounded transition at the middle connection. Simultaneously, the corners of the positioning block 11 are also rounded and coaxial with the rounded transition section in the middle of the forming upper die 14. By applying force to the inner and outer surfaces of the sheet metal part to be bent through the forming upper die 14 and the positioning block 11, the sheet metal part can be bent quickly and with high forming quality.
[0049] Furthermore, in combination Figure 4 and Figure 5 or Figure 7 and Figure 8 or Figure 10 and Figure 11 or Figure 13 and Figure 14As shown, the upper forming die 14 is connected to the slider 122 via a connecting shaft, and the connecting shaft is coaxially arranged with the upper forming die 14, allowing it to rise and fall synchronously with the slider 122. During the bending process of the sheet metal part, the upper forming die 14 can rotate around the connecting shaft, ensuring that the surface of the upper forming die 14 is subjected to uniform force, effectively preventing wear caused by localized force.
[0050] The pressure plate 13 is located outside the forming upper die 14. During the bending process, the inner bottom surface of the sheet metal part is placed on the positioning block 11, and its four sides are in contact with the four walls of the positioning block 11. The driving component 121 is activated to drive the pressure plate 13 to abut against the outer bottom surface of the sheet metal part. At the same time, the forming upper die 14 applies force to the outer surface of the corners of the sheet metal part, so that the corners of the sheet metal part are formed into rounded corners.
[0051] like Figure 3 As shown, the near end of the base 3 has a notch 30 that corresponds to the outer contour of the rounded corner sheet metal part. A fixing seat 130 is provided on the side of the slider 122 near the notch 30. A telescopic member 131 is provided on the fixing seat 130, and the pressure plate 13 is fixed to the bottom of the telescopic member 131. Initially, the pressure plate 13 is lower than the connecting shaft and first abuts against the sheet metal part after the drive component is activated. Then, the telescopic member 131 gradually compresses. The pressure plate 13 applies force to the sheet metal part to be processed, ensuring its stability during processing and thus guaranteeing its bending quality.
[0052] like Figure 3 As shown, an explosion-proof bending device further includes a trimming mechanism 2. The trimming mechanism 2 includes a trimming die 21 disposed on the lower surface of the base 3, and a cutter 211 formed on the trimming die 21, which is equivalent to the inner wall contour of the rounded corner sheet metal part. The cutter 211 can remove excess material from the bent rounded corner sheet metal part to form a finished product that meets the requirements.
[0053] Specifically, the cutting die 21 has a shape that matches the bottom end of the slider 122. Figure 5 and Figure 6 or Figure 8 and Figure 9 or Figure 11 and Figure 12 or Figure 14 and Figure 15The wedge-shaped groove 210 is shown. As the driving member 121 moves the slider 122 downward, the bottom of the slider 122 passes through the base 3 until the slider 122 is inserted into the wedge-shaped groove 210. The slider 122 drives the trimming die 21 to move towards the pressure plate 13 until the cutter 211 abuts against the notch 30 to cut off the part of the rounded corner sheet metal that protrudes from the outer edge of the sheet metal part, thus completing the bending process of the sheet metal part.
[0054] like Figures 3 to 15 As shown, the trimming mechanism 2 further includes a second guide rail 22 fixed to the lower surface of the base 3. The second guide rail 22 is disposed on both sides of the trimming die 21, and a groove for accommodating the trimming die 21 is formed on the second guide rail 22. Furthermore, the upper surface of the trimming die 21 is flush with the upper surface of the second guide rail 22. The trimming die 21 moves relative to the second guide rail 22 and the base 3, and the second guide rail 22 reduces the wobbling of the trimming die 21, resulting in smooth, burr-free edges on the cut sheet metal part, thus improving the cutting quality.
[0055] like Figure 5 , Figure 8 , Figure 11 and Figure 14 As shown, the trimming die 21 has a through hole for accommodating the reset member 23. The reset member 23 in this invention can be an elastic element such as a spring or silicone. Furthermore, both ends of the reset member 12 abut against the hole wall of the trimming die 21 and the mounting block 32, respectively. The mounting block 32 is fixed to the lower surface of the base 3 and located within the through hole of the trimming die 21. After cutting, the reset member 23 drives the trimming die 21 to automatically reset, preparing it for the processing of the next sheet metal part.
[0056] Both the trimming die 21 and the base 3 have through holes 203 for accommodating the upper forming die 14. A connecting bridge is provided within the through hole 203 on the trimming die 21, and the connecting bridge is centrally located along the width direction of the trimming die 21. A stop groove is formed on the connecting bridge for placing the middle connecting section of the upper forming die 14. As the upper forming die 14 moves downwards, it gradually approaches the connecting bridge and, in the cutting state, is positioned within the stop groove on the connecting bridge. That is, the connecting bridge and the stop groove limit the extreme positions of the upper forming die 14, ensuring that the sheet metal part is not subjected to excessive stress during processing, reducing the stress on the trimming die, and extending its service life.
[0057] The following is a brief description of the processing procedure of this utility model:
[0058] S0, the sheet metal part to be processed is placed upside down on the positioning block 11, that is, the inner surface of the sheet metal part abuts against the top surface and side wall of the positioning block 11, and the bent part of the sheet metal part corresponds to the corner of the positioning block 11; at this time, the forming component 12 is in the initial state, specifically as follows: Figures 4 to 6 As shown.
[0059] S1, activate the drive component 121 in the molding assembly 12 to move the slider 122 and the upper molding die 14 toward the positioning block 11 until the pressure plate 13 at the front end of the slider 122 abuts against the outer bottom surface of the sheet metal part, stabilizing the position of the sheet metal part; at this time, the molding assembly 12 is in the positioning state, specifically as follows: Figures 7 to 9 As shown.
[0060] S2, the driving component 121 continuously drives the slider 122 to move downward, causing the upper forming die 14 to gradually apply force to the edges and corners of the sheet metal part, and to bring the edges and corners of the sheet metal part closer to its inner surface, until the edges and corners of the sheet metal part are bent into rounded corners, forming a rounded corner sheet metal part; at the same time, the telescopic component 131 at the top of the pressure plate 13 gradually retracts, and the pressure plate 13 always abuts against the sheet metal part, forming a bent state, specifically as follows. Figures 10 to 12 As shown.
[0061] S3, the driving component 121 drives the slider 122 to reset, and at the same time, the slider 122 drives the pressure plate 13 to move upward and separate from the rounded corner sheet metal part, until the forming component is reset to the desired position. Figures 4 to 6 The initial state is shown.
[0062] S4, place the rounded corner sheet metal part at the notch 30 of the base 3 and fit it with the notch 30; and the rounded corner sheet metal part is upside down on the cutting mold 21, with the excess part of the rounded corner sheet metal part at the bend located at the cutter on the cutting mold 21.
[0063] S5, the drive unit 121 is activated again, causing the slider 122 to move downwards again until the wedge at the bottom of the slider 122 gradually inserts into the wedge groove 210 on the trimming die 21; during this process, the trimming die 21 gradually moves towards the forming upper die 14, cutting off the excess portion on the rounded corner sheet metal part, so that the cutter 211 moves to the position shown in the image. Figures 13 to 15 The cutting state shown.
[0064] This utility model has many other embodiments. All technical solutions formed by equivalent transformation or equivalent transformation fall within the protection scope of this utility model.
Claims
1. An explosion-proof bending device, which is arranged on a base (3); characterized in that: The system includes a bending mechanism (1) and a trimming mechanism (2); the bending mechanism (1) includes a positioning block (11) disposed on the base (3) and a forming component (12) disposed above the positioning block (11); the forming component (12) is disposed on a bracket (31), and the bracket (31) is fixed to the upper surface of the base (3); the forming component (12) includes a driving member (121) disposed on the top surface of the bracket (31), and the driving member (121) is... 1) The end of the bracket (31) is fixed with a slider (122) and a pressure plate (13); the upper forming mold (14) is provided on the inner side of the slider (122), and the pressure plate (13) is located on the outer side of the upper forming mold (14); the inner bottom surface of the sheet metal part is placed on the positioning block (11), and the four sides are in contact with the four walls of the positioning block (11). The drive unit (121) is activated to drive the pressure plate (13) to abut against the outer bottom surface of the sheet metal part, and at the same time the forming The upper mold (14) applies force to the outer surface of the corner of the sheet metal part, so that the corner of the sheet metal part is formed into a rounded corner; the near end of the base (3) is provided with a notch (30) corresponding to the outer wall contour of the rounded corner sheet metal part; the trimming mechanism (2) includes a trimming mold (21) provided on the lower surface of the base (3), and a cutter (211) corresponding to the inner wall contour of the rounded corner sheet metal part is formed on the trimming mold (21); the trimming mold (21) is provided with a cutter (211) corresponding to the inner wall contour of the rounded corner sheet metal part; the trimming mold (21) is provided with a cutter corresponding to the slider (122). The bottom end is matched with a wedge-shaped groove (210); the driving member (121) drives the slider (122) to move down, through the base (3) until the slider (122) is inserted into the wedge-shaped groove (210), the slider (122) drives the trimming die (21) to move towards the pressure plate (13) until the cutter (211) abuts against the notch (30) to cut off the part of the rounded corner sheet metal that protrudes from the outer edge of the sheet metal part, and complete the bending process of the sheet metal part.
2. The explosion-proof bending device according to claim 1, characterized in that: The upper forming mold (14) is hourglass-shaped, and the middle connection is transitioned by a rounded arc; the corner of the positioning block (11) is rounded, and it is coaxial with the middle rounded arc transition section of the upper forming mold (14).
3. The explosion-proof bending device according to claim 2, characterized in that: The upper forming mold (14) is connected to the slider (122) via a connecting shaft, and the connecting shaft is coaxially arranged with the upper forming mold (14) so that it rises and falls synchronously with the slider (122).
4. The explosion-proof bending device according to claim 3, characterized in that: A fixed seat (130) is provided on the side of the slider (122) near the notch (30). A telescopic member (131) is provided on the fixed seat (130). The pressure plate (13) is fixed to the bottom of the telescopic member (131). In the initial state, the pressure plate (13) is lower than the connecting shaft and first abuts against the sheet metal part after the drive is started. Then the telescopic member (131) is gradually compressed.
5. The explosion-proof bending device according to claim 4, characterized in that: The bracket (31) includes two vertically arranged first guide rails (311) and a cover plate (312) vertically fixed to the top of the first guide rails (311); the inner wall of the first guide rails (311) forms a guide groove for accommodating the slider (122); the driving member (121) is fixed on the cover plate (312), and its driving end passes through the cover plate (312).
6. The explosion-proof bending device according to claim 5, characterized in that: The trimming mechanism (2) further includes a second guide rail (22) fixed to the lower surface of the base (3). The second guide rail (22) is disposed on both sides of the trimming mold (21), and a groove for accommodating the trimming mold (21) is formed on the second guide rail (22). The trimming mold (21) moves relative to the second guide rail (22) and the base (3). The upper surface of the trimming mold (21) is flush with the upper surface of the second guide rail (22).
7. The explosion-proof bending device according to claim 6, characterized in that: The cutting die (21) has a through hole for accommodating the reset member (23). The reset member (23) is an elastic member, and its two ends abut against the hole wall of the cutting die (21) and the mounting block (32) respectively. The mounting block (32) is fixed to the lower surface of the base (3) and located in the through hole of the cutting die (21).
8. The explosion-proof bending device according to claim 7, characterized in that: Both the trimming die (21) and the base (3) have through holes (203) for accommodating the upper forming die (14).
9. The explosion-proof bending device according to claim 8, characterized in that: A connecting bridge is provided in the through hole (203) on the cutting die (21). The connecting bridge is centrally located along the width direction of the cutting die (21), and a stop groove is formed on the connecting bridge for placing the middle connecting section of the upper forming die (14).