Multi-station progressive die for metal strips

Abstract

The invention relates to the technical field of multi-station progressive dies, and discloses a metal strip multi-station progressive die which comprises an upper closing die and a lower closing die, the lower closing die is provided with a target feeding groove and an auxiliary material feeding groove which are perpendicular to each other, a target metal strip is vertically fed in the rolling line direction of the target metal strip, and an auxiliary material strip is transversely fed. A positioning punching needle, a punching cutter, a convex hull and a matched punching needle are arranged on a corresponding path of the upper closing die; in the intersection area of the two grooves, the punched target metal sheet is riveted to the auxiliary material belt through the riveting punch and the riveting positioning table to form the composite feeding unit, through the structure, the follow-up bending axis is perpendicular to the material rolling line direction, transverse forming cracking and springback out-of-tolerance are effectively avoided, and the forming quality and consistency of the circuit breaker support are improved.

Description

Technical Field

[0001] This invention relates to the field of stamping equipment technology, specifically to a multi-station progressive die for metal strip. Background Technology

[0002] In the field of low-voltage electrical appliance manufacturing, circuit breakers are core protection components. Their internal metal supports (such as operating mechanism supports, contact supports, arc-extinguishing chamber mounting brackets, etc.) are usually mass-produced using high-precision cold stamping processes. These parts have complex structures and often include multiple bends, bulges, positioning holes, etc., requiring extremely high dimensional accuracy, surface quality, and mechanical properties. Currently, the industry generally uses multi-station progressive dies to continuously punch, form, and bend metal strips to achieve efficient and automated production.

[0003] However, the materials used to manufacture circuit breaker brackets are mostly copper-plated. These metals form obvious anisotropic structures during rolling, meaning that their ductility and tensile strength along the rolling direction are significantly better than those in the transverse direction. In traditional progressive dies, the metal strip is usually fed continuously in the transverse direction along the equipment feeding direction, which means that the bending axis of the key bending process is often parallel to the rolling grain direction of the material. When bending is performed under this orientation, the outer tension area of ​​the material is in a transverse low plasticity state, which makes it very easy to produce microcracks, edge tearing or severe springback.

[0004] Therefore, there is an urgent need for a multi-station progressive die for metal strip that can actively adapt to the rolling pattern direction of the material without sacrificing material utilization and production efficiency, and achieve integrated high-precision forming of complex brackets, so as to meet the increasingly stringent quality and cost requirements of high-end low-voltage electrical appliances such as circuit breakers for core metal structural components. Summary of the Invention

[0005] To solve the above-mentioned technical problems, the present invention provides a multi-station progressive die for metal strip.

[0006] To achieve the above objectives, the present invention provides the following technical solution: A multi-station progressive die for forming metal strip is provided for forming circuit breaker metal supports. It includes an upper die and a lower die. The upper die is connected to a punch press and can be driven by the punch press to perform vertical stamping motion. The lower die has a target feed groove and an auxiliary feed groove. The target feed groove extends vertically to feed the target metal strip along its rolling grain direction. The auxiliary feed groove extends laterally to feed auxiliary strip. The target feed groove and the auxiliary feed groove are spatially perpendicular to each other. The upper die corresponds to... The target feed trough is provided with positioning punch pins, cutting blades and convex forming pins in sequence on the feed path for punching the target metal strip into sheets. The upper die is provided with positioning punch pins, cutting blades and cooperating punch pins in sequence on the feed path corresponding to the auxiliary material feed trough. The lower die is provided with a riveting positioning table in the intersection area of ​​the target feed trough and the auxiliary material feed trough. The upper die is also provided with a riveting punch, which cooperates with the riveting positioning table to rivet and fix the target metal sheet to the auxiliary material strip to form a composite feeding unit.

[0007] To ensure high-precision alignment between the target metal sheet and the auxiliary strip before riveting, preferably, the target metal strip is located below the auxiliary strip, and the protrusion formed by the protrusion forming needle on the target metal strip corresponds vertically to the mating punch formed by the mating punching needle on the auxiliary strip.

[0008] To prevent the positioning punch from breaking due to excessive impact load during high-speed continuous punching and to facilitate material removal, preferably, the positioning punch includes a positioning sleeve fixedly installed on the bottom surface of the upper mold. An anti-breakage pin is fixedly installed inside the positioning sleeve. The positioning sleeve includes a fixed end and a movable end, with the movable end connected to the fixed end via an elastic element.

[0009] In order to perform high-precision forming of the target metal sheet after riveting, preferably, the downstream of the riveting positioning table is provided with multiple forming mechanisms and bending mechanisms for performing multi-step dimensional correction and multi-angle bending forming of the target metal sheet that has been riveted to the auxiliary strip.

[0010] To achieve high-precision springback compensation and surface correction for key components, the forming mechanism further includes a main forming station. The main forming station includes a horizontal rod and a wedge rod that are slidably installed in the upper mold. The horizontal rod and the wedge rod are perpendicular to each other in spatial arrangement. A base is fixedly installed in the lower mold. A forming block is connected to the base through an elastic element. The forming block has an inclined surface 1 that matches the wedge rod and an inclined surface 2 that contacts the target metal sheet.

[0011] In order to achieve rigid limiting in the final pressing stage to ensure the stability of the forming dimensions, the main forming station further includes a second forming block fixedly installed on the bottom surface of the upper mold. The side of the second forming block facing the lower mold has a protrusion, and the first forming block has a groove to accommodate the protrusion.

[0012] To facilitate adjustment of the forming stroke to accommodate material thickness tolerances and to prevent the forming reaction force from causing the adjustment mechanism to loosen, the horizontal rod has a connecting block integrally formed at one end outside the upper mold. The connecting block has an internal thread for threaded connection of a fastening bolt, and the upper mold has a corresponding threaded hole. The horizontal rod has a flat groove at one end near the wedge rod, and the corresponding contact surface between the flat groove and the wedge rod is planar.

[0013] To fully utilize the high ductility of the material in the rolling direction and avoid bending cracks, the bending mechanism further includes a main bending station, which includes a bending insert and a bending seat. The bending insert is driven downward by the upper die to cooperate with the bending seat to perform a main bend on the target metal bracket, and the bending axis of the main bend is perpendicular to the rolling grain direction of the target metal bracket.

[0014] The beneficial effects of this invention are: 1. By setting mutually perpendicular target feed troughs and auxiliary feed troughs, and feeding the target metal strip vertically along its rolling texture direction and the auxiliary strip laterally, and then forming a composite feeding unit by riveting, the bending axis is made perpendicular to the rolling texture direction of the material in the subsequent bending forming, which effectively avoids cracking and excessive springback caused by material anisotropy.

[0015] 2. By setting up a main forming station consisting of a horizontal bar, a wedge bar, a floating forming block one, and a fixed forming block two, and by adopting a planar fit structure of a plane groove and a wedge bar, the beneficial effects of high-precision multi-directional forming of the target metal sheet and isolation of forming reaction force are achieved. This ensures dimensional consistency and prevents the adjustment mechanism from loosening due to force return. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the overall structure of the present invention; Figure 2 for Figure 1 Second perspective; Figure 3 The lower mold structure of the present invention and the corresponding positions of the positioning punch pin, the punching cutter, the convex forming pin, and the mating punch pin; Figure 4 This is a plan view of the mating of the upper and lower molds of the present invention; Figure 5 This is a schematic diagram of the shaping mechanism structure of the present invention; Figure 6 for Figure 5 Enlarged view of the A-structure; Figure 7 This is a schematic diagram of the bending mechanism structure of the present invention; Figure 8 The stamping steps for the target strip and auxiliary strip of this invention are described.

[0017] The attached diagram lists the components represented by each number as follows: 10. Upper mold; 11. Positioning punch pin; 110. Positioning sleeve; 111. Anti-breakage pin; 112. Fixed end; 113. Moving end; 12. Punching cutter; 13. Matching punch pin; 14. Riveting punch; 101. Threaded hole; 20. Lower mold closing device; 201. Target feed groove; 202. Auxiliary material feed groove; 21. Riveting positioning table; 22. Convex forming pin; 30. Shaping mechanism; 31. Horizontal bar; 311. Connecting block; 32. Wedge rod; 33. Base; 34. Shaping block one; 35. Shaping block two; 301. Protrusion; 302. Groove; 303. Flat groove; 40. Bending mechanism; 41. Bending insert; 42. Bending seat. Detailed Implementation

[0018] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and 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. Therefore, they should not be construed as limitations on this invention. Example 1

[0020] like Figure 1 - Figure 8As shown, this invention relates to a multi-station progressive die for metal strip, used for forming metal supports for circuit breakers. It mainly includes an upper die 10 and a lower die 20. The upper die 10 is connected to a punch press and can be driven by the punch press to perform vertical stamping movements, completing the stamping actions at each station. The lower die 20 is fixed to the punch press worktable, serving as a reference platform for the entire feeding and forming process. The lower die 20 has a target feed groove 201 and an auxiliary feed groove 202. Specifically, the target feed groove 201 extends vertically to allow the target metal strip to feed along its rolling grain direction. The target metal strip is plated... The copper material is fed laterally by an auxiliary material feed trough 202, which is made of low-carbon steel. The target feed trough 201 and the auxiliary material feed trough 202 are spatially perpendicular to each other. The upper mold 10 is provided with multiple sets of positioning punch pins 11 and cutting blades 12 on the feed path corresponding to the target feed trough 201 for punching the target metal strip into sheets. Specifically, the positioning punch pins 11 are used to punch process positioning holes on the target metal strip to provide a reference for subsequent punching, transfer, and bending. The cutting blades 12 are provided in multiple sets with different shapes and are used to cut the positioned target metal strip. The metal sheet is punched and cut into individual pieces, forming the circuit breaker metal bracket blank. A convex forming pin 22 is installed on the lower die 20. The convex forming pin 22 presses out a convex structure at a specific position on the metal sheet. This convex structure can be used for subsequent assembly positioning and also serves as an alignment feature for mating with the auxiliary material strip. Simultaneously, the upper die 10 has multiple sets of positioning punching pins 11, cutting blades 12, and mating punching pins 13 sequentially arranged on the feed path corresponding to the auxiliary material feed groove 202. The positioning punching pins 11 punch positioning holes on the auxiliary material strip to ensure synchronization with the punch press feeding mechanism. The cutting blades… 12 is also equipped with multiple sets of different shapes. The auxiliary material strip is segmented and contoured according to the pitch requirements. The punching pin 13 punches through holes at predetermined positions on the auxiliary material strip. The through holes correspond vertically to the protrusions on the target metal sheet, forming a mechanical pre-alignment structure. The lower mold 20 is provided with a riveting positioning table 21 in the intersection area of ​​the target feed groove 201 and the auxiliary material feed groove 202. Furthermore, the target metal strip is located below the auxiliary material strip, and the protrusions formed by the protrusion forming pin 22 on the target metal strip correspond vertically to the matching punches punched by the punching pin 13 on the auxiliary material strip. After the target metal sheet completes the outer shape punching and convex forming, it moves to the riveting positioning table 21 under the feed of the subsequent strip. After the auxiliary strip completes the outer shape punching and mating hole forming, it is precisely stacked on top of the target metal strip that has been sent to the position under the feed of the subsequent strip. With the stamping action of the upper die 10, the punching cutter 12 punches the target metal strip into individual metal sheets. At the same time, the upper die 10 is also equipped with a riveting punch 14, which cooperates with the riveting positioning table 21 to rivet and fix the target metal sheet to the auxiliary strip by pressing and riveting, forming a composite feeding unit.

[0021] The composite feeding unit is then driven by the auxiliary conveyor belt and continues to feed laterally to the downstream station. It is worth noting that although the feeding direction is laterally, the rolling pattern of the target metal sheet itself remains vertical. Therefore, during the forming process in the subsequent processing, its main deformation direction is perpendicular to the pattern direction, thereby making full use of the material's high ductility in the vertical direction and effectively avoiding problems such as cracking, poor springback or edge burrs caused by insufficient lateral plasticity.

[0022] Reference Figure 2 and Figure 7 In this embodiment, the positioning punch 11 is not a traditional one-piece punch, but a split buffer anti-breakage structure to deal with the frequent impacts and the problem of easy material jamming during high-speed progressive stamping. Specifically, the positioning punch 11 includes a positioning sleeve 110 fixedly installed on the bottom surface of the upper mold 10. The positioning sleeve 110 has a cylindrical structure, and its upper end is embedded in the mounting hole of the upper mold 10 by a screw. An anti-breakage needle 111 is fixedly installed inside the positioning sleeve 110. The anti-breakage needle 111 is a solid punch made of high-hardness alloy steel, and its lower end is a punching edge, which is used to punch process positioning holes on the target metal strip and the auxiliary strip. At the same time, it is used for positioning during the continuous feeding of the target metal strip and the auxiliary strip. The key point is that the positioning sleeve 110 is not a rigid whole, but includes a fixed end 112 and a movable end 113. The fixed end 112 is directly connected to the upper mold 10 and serves as a structural support base. The movable end 113 is sleeved on the outside or inside of the fixed end 112 and can slide slightly along the axial direction. The movable end 113 is connected to the fixed end 112 through an elastic element, preferably a compression spring, which is pre-placed in the annular cavity between the two.

[0023] In the initial stage of stamping, the upper die 10 drives the entire positioning punch 11 to move downward. When the anti-breakage needle 111 contacts the surface of the metal strip and begins to punch, if the material hardness is uneven or there are inclusions, the impact load will increase instantaneously. Traditional rigid punches are prone to bending due to stress concentration. However, in this structure, the movable end 113 can overcome the pre-pressure of the elastic element under the action of impact force and generate a partial axial compression displacement relative to the fixed end 112, thereby absorbing part of the impact energy and realizing "flexible buffering". At the same time, when the movable end 113 is reset, the strip stuck on the anti-breakage needle 111 can be removed. Example 2

[0024] Reference Figure 1 , Figures 3 to 8 Downstream of the riveting positioning table 21 are multiple forming mechanisms 30 and bending mechanisms 40, which are used to perform multi-step size correction and multi-angle bending of the target metal sheet that has been riveted to the auxiliary material strip, together forming the high-precision forming area of ​​the composite feeding unit.

[0025] As mentioned above, after the riveting punch 14 and the riveting positioning table 21 act, the target metal sheet is firmly riveted to the auxiliary material strip, forming a rigidly connected composite feeding unit. This unit uses the auxiliary material strip as a process carrier and is continuously fed into the downstream station laterally under the drive of the progressive feeding mechanism.

[0026] It is worth noting that although the overall feeding direction is horizontal, the rolling pattern of the target metal sheet itself remains vertical, which provides an ideal material property basis for its subsequent forming.

[0027] Reference Figure 5 , Figure 6 The forming mechanism 30 includes a main forming station for performing critical dimension correction and springback compensation on the target metal sheet that has been riveted to the auxiliary strip. The main forming station includes a horizontal rod 31 and a wedge rod 32 that are slidably installed in the upper mold 10. The horizontal rod 31 and the wedge rod 32 are perpendicular to each other in spatial arrangement. A base 33 is fixedly installed in the lower mold 20. A forming block 34 is connected to the base 33 by an elastic element, preferably a compression spring. The forming block 34 has a slope 1 that is adapted to the wedge rod 32 and a slope 2 that contacts the target metal sheet.

[0028] The main shaping station also includes a second shaping block 35 fixedly installed on the bottom surface of the upper mold 10. The side of the second shaping block 35 facing the lower mold 20 has a protrusion 301, and the first shaping block 34 has a groove 302 to accommodate the protrusion 301. When the upper mold 10 descends to the final pressure position, the protrusion 301 is embedded in the groove 302, applying the final finishing pressure to the first shaping block 34, thus achieving the dual function of "rigid limiting and elastic buffering".

[0029] During the stamping process, the upper die 10 drives the entire main forming station to move down synchronously. In the initial stage, the second forming block 35 first contacts the surface of the target metal sheet and performs preliminary flattening. In the middle stage, the wedge-shaped surface of the wedge rod 32 acts on the inclined surface of the first forming block 34, moving it laterally. The inclined surface of the first forming block 34 contacts the target metal sheet and performs three-dimensional surface finishing. At the same time, the protrusion 301 of the second forming block 35 gradually embeds into the groove 302 of the first forming block 34 to achieve final size locking. During this process, the target metal sheet completes springback compensation and shape correction under the synergistic action of the upper and lower forming blocks.

[0030] During the final pressing stage, the nested fit between the protrusion 301 and the groove 302 prevents the shaping block 34 from moving excessively and avoids overpressure damage to the workpiece.

[0031] During the stamping process, when the forming is completed and the upper die 10 returns, if the forming block 34 generates a reaction force due to the elastic element resetting or the workpiece rebounding, this force may push the horizontal rod 31 back through the wedge rod 32, causing the horizontal rod 31 to shift its adjustment position and affecting the forming accuracy of the next time. (Refer to...) Figure 4 Specifically, the horizontal rod 31 has a connecting block 311 integrally formed at one end outside the upper mold 10. The connecting block 311 has an internal thread for threaded connection of a fastening bolt. The upper mold 10 has a corresponding threaded hole 101. The horizontal rod 31 has a flat groove 303 at one end near the wedge rod 32. The corresponding contact surface between the flat groove 303 and the wedge rod 32 is a planar fit.

[0032] When the wedge rod 32 attempts to push the horizontal rod 31 in the opposite direction, the reaction force is also horizontal because the contact surface is a horizontal plane. However, the horizontal rod 31 is locked in the threaded hole 101 of the upper mold 10 by the fastening bolt and cannot move freely. After adjustment, no matter where the horizontal rod 31 is, it is always in surface contact with the wedge rod 32. The contact area is large and the stress distribution is uniform, ensuring that the stroke of the wedge rod 32 is consistent each time, thereby controlling the moving distance of the shaping block 34.

[0033] Reference Figure 7 The bending mechanism 40 includes a main bending station, which includes a bending insert 41 and a bending seat 42. The bending insert 41 is driven downward by the upper die 10 to cooperate with the bending seat 42 to perform a main bending on the target metal bracket, and the bending axis of the main bending is perpendicular to the rolling pattern direction of the target metal bracket.

[0034] The target metal bracket is precisely delivered to the bending station by the auxiliary material belt. The upper die 10 moves downward, and the bending insert 41 first presses the target bracket tightly onto the bending seat 42 to prevent slippage. The bending insert 41 continues to move downward, and its rounded end gradually bends the target bracket around the bending seat 42 to the target angle. Because the bending direction is perpendicular to the grain, when the bending insert 41 is pressed down, the material fiber direction of the tension area on the outer side of the bent target metal bracket is consistent with the tensile stress direction, giving full play to the material's longitudinal high ductility advantage.

[0035] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely preferred examples and are not intended to limit the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. A multi-position progressive die for the forming of a metal bracket for a circuit breaker, comprising an upper die half (10) and a lower die half (20), the upper die half (10) being connected to and vertically strikable by a punch press, characterised in that, The lower die (20) is provided with a target feed groove (201) and an auxiliary feed groove (202). The target feed groove (201) extends vertically to feed the target metal strip along its rolling pattern. The auxiliary feed groove (202) extends horizontally to feed the auxiliary strip. The target feed groove (201) and the auxiliary feed groove (202) are perpendicular to each other in spatial arrangement. The upper die (10) is provided with a positioning punch (11) and a punching cutter (12) in sequence on the feed path corresponding to the target feed groove (201). The lower die (20) is equipped with a convex forming pin (22) for punching the target metal strip into sheets. The upper die (10) is provided with a positioning punch (11), a punching cutter (12) and a mating punch (13) in sequence on the feed path corresponding to the auxiliary feed groove (202). The lower die (20) is provided with a riveting positioning table (21) in the area where the target feed trough (201) and the auxiliary feed trough (202) intersect. The upper die (10) is also provided with a riveting punch (14), which cooperates with the riveting positioning table (21) to rivet and fix the target metal sheet on the auxiliary material strip to form a composite feeding unit.

2. The multi-stage progressive die for a metal strip according to claim 1, wherein: The target metal strip is located below the auxiliary strip, and the convex bulge formed by the convex bulge forming needle (22) on the target metal strip corresponds vertically to the matching punch formed by the matching punching needle (13) on the auxiliary strip.

3. The multi-stage progressive die for a metal strip as set forth in claim 1, wherein: The positioning punch (11) includes a positioning sleeve (110) fixedly installed on the bottom surface of the upper mold (10). An anti-breakage needle (111) is fixedly installed inside the positioning sleeve (110). The positioning sleeve (110) includes a fixed end (112) and a movable end (113). The movable end (113) is connected to the fixed end (112) through an elastic element.

4. A multi-stage progressive die for a metal strip as defined in claim 1, wherein: Downstream of the riveting positioning table (21) are provided multiple shaping mechanisms (30) and bending mechanisms (40) for performing multi-step dimensional correction and multi-angle bending on the target metal sheet that has been riveted to the auxiliary strip.

5. The multi-stage progressive die for a metal strip as set forth in claim 4, wherein: The shaping mechanism (30) includes a main shaping station, which includes a horizontal rod (31) and a wedge rod (32) slidably installed in the upper mold (10). The horizontal rod (31) and the wedge rod (32) are perpendicular to each other in spatial arrangement. A base (33) is fixedly installed in the lower mold (20). A shaping block (34) is connected to the base (33) by an elastic element. The shaping block (34) has an inclined surface (1) that matches the wedge rod (32) and an inclined surface (2) that contacts the target metal sheet.

6. A multi-station progressive die for metal strip according to claim 5, characterized in that: The main shaping station also includes a shaping block two (35) fixedly installed on the bottom surface of the upper mold (10). The shaping block two (35) has a protrusion (301) on the side facing the lower mold (20), and the shaping block one (34) has a groove (302) to accommodate the protrusion (301).

7. A multi-station progressive die for metal strip according to claim 5, characterized in that: The horizontal bar (31) has a connecting block (311) integrally formed at one end outside the upper mold (10). The connecting block (311) has an internal thread for threaded connection of a fastening bolt. The upper mold (10) has a corresponding threaded hole (101). The horizontal bar (31) has a flat groove (303) at one end near the wedge bar (32), and the corresponding contact surface of the flat groove (303) and the wedge bar (32) is in planar fit.

8. A multi-station progressive die for metal strip according to claim 4, characterized in that: The bending mechanism (40) includes a main bending station, which includes a bending insert (41) and a bending seat (42). The bending insert (41) is driven downward by the upper die (10) to cooperate with the bending seat (42) to perform a main bending on the target metal bracket, and the bending axis of the main bending is perpendicular to the rolling pattern direction of the target metal bracket.

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