An inward bending device for metal sheets

Abstract

This invention relates to the field of sheet metal technology, specifically to an inward flanging bending device for metal sheets. The device includes a cutter body, a centering mechanism, and two ear blades. The cutter body is movable vertically. The two ear blades are symmetrically arranged on the left and right sides of the cutter body, each forming a wedge-shaped guide engagement with the cutter body and capable of moving outward and upward or inward and downward relative to the cutter body. The centering mechanism is used to ensure that the bending center of the metal sheet coincides with the center of symmetry of the two ear blades. When flanging and bending the metal sheet, the cutter body is first moved downward. After the two ear blades contact the metal sheet, as the cutter body continues to move downward, the two ear blades, through the wedge-shaped guide engagement with the cutter body, move synchronously outward and upward relative to the cutter body. Simultaneously, the centering mechanism centers the metal sheet, allowing for bending of the sheet metal and ensuring bending effect and accuracy.

Description

Technical Field

[0001] This invention relates to the field of sheet metal technology, and in particular to an inward bending device for metal sheets. Background Technology

[0002] In modern industrial manufacturing systems, metal forming and processing technology is the core foundation for constructing industrial product structures. Through diverse plastic processing techniques such as rolling, drawing, and extrusion, metal materials can be given multiple forms such as tubular, plate, and rod shapes to adapt to the application needs of different industries.

[0003] In the metal sheet forming process, the bending process is a key step in realizing three-dimensional structure forming, which directly determines the final shape and quality of the product. The bending process transforms two-dimensional flat material into three-dimensional components with specific angles and shapes by applying local plastic deformation. Its precision control directly affects the adaptability of subsequent assembly processes.

[0004] When bending metal sheets, bending tools are required. For example, Chinese patent CN219151345U discloses a bending tool for a four-sided inward-folding door panel. By setting up side pressure members and a middle pressure member, when processing the four-sided inward-folding door panel, the side pressure member first enters between the two inward-folding edges, pressing against the position to be bent. Then, the middle pressure member is pressed down, and the trapezoidal blade of the middle pressure member pushes the side pressure member outward until the bottom surface of the side pressure member is flush with the bottom surface of the blade. The middle pressure member also enters between the two inward-folding edges. Through this secondary pushing method, the entire bending tool can overcome the obstruction of the two inward-folding edges and bend the other two inward-folding edges to form a four-sided inward-folding door panel.

[0005] However, the bending cutters for the aforementioned four-sided inward-folding door panels also have some problems in actual use: Since the working principle of the side pressure component mainly relies on pre-avoiding the already formed folded edge, the operator needs to leave a safety gap when placing the door panel. Without high-precision positioning assistance, manual placement is very likely to cause the center of the door panel to shift. This positioning deviation will cause uneven force during the bending process: when the gap on one side is less than the design value, the extrusion force on that side is too large, resulting in over-bending and material thinning; while the other side will have a deviation in bending angle due to insufficient pressure. In addition, uneven force will also accelerate the local wear of the bending cutter, shorten the service life of the side pressure component, and increase the maintenance cost and downtime of the bending cutter. Summary of the Invention

[0006] Therefore, it is necessary to provide an internal flanging bending device for metal sheets to address the problems of poor bending effect, low bending accuracy, and short service life of bending tools in the current metal sheet bending process.

[0007] The above objectives are achieved through the following technical solutions:

[0008] An inward flanging bending device for metal sheets, the inward flanging bending device for metal sheets comprising:

[0009] The main body of the cutting tool can move vertically;

[0010] Two ear blades are symmetrically arranged on the left and right sides of the cutter body. Each ear blade forms a wedge-shaped guide fit with the cutter body and can move outward and upward or inward and downward relative to the cutter body.

[0011] The centering mechanism is configured to make the bending center of the metal sheet coincide with the symmetry center of the two ear blades;

[0012] The centering mechanism includes a friction plate and a symmetry assembly. The friction plate is disposed on the cutter body. Each ear cutter is fitted with a push rod and an adjusting rod. The push rod can slide along the direction of the arrangement of the two ear cutters and can both form a stop engagement with the ear cutter and extend out of the ear cutter. The adjusting rod can slide along the direction of the arrangement of the two ear cutters. A first elastic element is disposed between the push rod and the adjusting rod. An intermediate sleeve is threaded onto both of the two adjusting rods. Friction rings are fixedly sleeved at both ends of the intermediate sleeve, and the friction rings can form a friction transmission engagement with the friction plate. The symmetry assembly is configured to make the two push rods symmetrically arranged about the symmetry center of the two ear cutters.

[0013] The symmetrical component includes a push rod, and each of the ear blades is provided with the push rod. The push rod can slide in the vertical direction and can form a stop engagement with the cutter body and a wedge-shaped guide engagement with the top rod. It is connected to the ear blade through a second elastic element.

[0014] Furthermore, the second elastic element is a second compression spring.

[0015] Furthermore, the first elastic element is a first compression spring.

[0016] Furthermore, guide rails are detachably provided on both the left and right sides of the cutter body; the ear cutter is slidably sleeved on the guide rails.

[0017] Furthermore, each of the ear cutters is fitted with a tensioning shaft, and each tensioning shaft is fitted with at least one elastic ring. The elastic ring can form a stop engagement with the guide rail to increase the contact pressure between the ear cutter and the guide rail.

[0018] Furthermore, each of the ear blades contains three tensioning shafts.

[0019] Furthermore, each of the ear blades is also fitted with a screw, which is slidably inserted into the guide rail.

[0020] Furthermore, the guide rail is detachably connected to the cutter body via a nut.

[0021] The beneficial effects of this invention are:

[0022] This invention relates to an inward flanging bending device for metal sheets. By setting a centering mechanism, the bending center of the metal sheet coincides with the symmetrical center of the two ear blades before bending. This allows the metal sheet to be bent in a centered manner, avoiding uneven force during bending due to positioning deviation, ensuring bending effect and accuracy, and preventing accelerated wear of the tool body and ear blades due to uneven force, thus ensuring the service life of the tool body and ear blades. Attached Figure Description

[0023] Figure 1 This is a three-dimensional structural diagram of the metal sheet inward flanging bending device provided in an embodiment of the present invention;

[0024] Figure 2 A three-dimensional structural diagram of the tool body, ear knife, and centering mechanism of the metal sheet inward flanging bending device provided in an embodiment of the present invention during assembly;

[0025] Figure 3 This is a side view of the assembly structure of the cutter body, ear cutter, and centering mechanism of the metal sheet inward flanging bending device provided in an embodiment of the present invention.

[0026] Figure 4 An exploded view of the cutter body, ear cutter, and centering mechanism of the metal sheet inward flanging bending device provided in an embodiment of the present invention;

[0027] Figure 5 for Figure 4 A magnified schematic diagram of the structure at point Z in the middle;

[0028] Figure 6 A three-dimensional structural diagram of the tool body, a single ear blade, and the centering mechanism of the metal sheet inward flanging bending device provided in this embodiment of the invention. Figure 1 ;

[0029] Figure 7 A three-dimensional structural diagram of the tool body, a single ear blade, and the centering mechanism of the metal sheet inward flanging bending device provided in this embodiment of the invention. Figure 2 ;

[0030] Figure 8 This is a side view of the ear blade of the metal sheet inward flanging bending device provided in an embodiment of the present invention.

[0031] Figure 9 for Figure 8 A three-dimensional sectional view along the AA direction;

[0032] Figure 10 for Figure 8 A three-dimensional sectional view along the BB direction;

[0033] Figure 11 This is a three-dimensional structural diagram of the guide rail of the metal sheet inward flanging bending device provided in an embodiment of the present invention.

[0034] in:

[0035] 1. Tool body; 101. Guide rail; 1011. Through hole; 1012. Second slide groove; 102. First wedge surface;

[0036] 2. Ear blade; 201. Tensioning shaft; 202. Elastic ring; 203. Screw; 204. Second wedge surface; 205. First groove; 206. First mounting hole; 207. Ear plate; 208. Second mounting hole; 209. Third mounting hole;

[0037] 301. Friction plate; 302. Symmetrical assembly; 3021. Push rod; 30211. Retaining ring; 30212. Wedge head; 3022. Second compression spring; 303. Top rod; 3031. Wedge hole; 304. Adjusting rod; 305. First compression spring; 306. Intermediate sleeve; 307. Friction ring;

[0038] 4. Rack;

[0039] 5. Drive cylinder. Detailed Implementation

[0040] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below through embodiments and in conjunction with the accompanying drawings. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0041] The serial numbers assigned to components in this document, such as "first," "second," etc., are merely used to distinguish the described objects and do not have any sequential or technical meaning. The terms "connection" and "linkage" used herein, unless otherwise specified, include both direct and indirect connections (linkages). In the description of this invention, it should be understood that the terms "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 used solely for the convenience of describing the invention and for 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 the invention.

[0042] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0043] The following reference Figures 1 to 11 The present invention describes an internal flanging and bending device for metal sheets, which is particularly suitable for flanging and bending metal sheets, and of course, it is also suitable for flanging and bending sheets of other materials.

[0044] Specifically, the metal sheet internal flanging bending device includes a frame 4, on which at least one drive cylinder 5 is mounted. The output shaft of the drive cylinder 5 is vertically downward and mounted on the cutter body 1, thereby driving the cutter body 1 to move vertically, facilitating the bending of the metal sheet. The left and right side walls of the cutter body 1 are both first wedge surfaces 102, forming a V-shape with the smaller opening facing downward. A guide rail 101 is provided at each first wedge surface 102, with the guide rail 101 parallel to the inclination direction of the first wedge surface 102. Multiple through holes 1011 are provided on the guide rail 101, spaced apart along the extension direction of the guide rail 101. A countersunk groove is provided at the outer end of each through hole 1011, and a nut is inserted into each through hole 1011. The female guide rail 101 is threaded into the tool body 1 through the through hole 1011 and simultaneously stops at the countersunk groove, thus detachably connecting the guide rail 101 to the tool body 1. Two ear blades 2 are symmetrically arranged on the left and right sides of the tool body 1. The inner wall of each ear blade 2 is configured as a second wedge surface 204, which is parallel to the first wedge surface 102. The two second wedge surfaces 204 together form a figure-eight structure with the smaller opening facing downwards. A first sliding groove 205 is provided on each second wedge surface 204, and the inclination directions of the first sliding groove 205 and the second wedge surface 204 are parallel. During installation, the ear blade 2 slides onto the guide rail 101 through the first sliding groove 205, thus forming a wedge-shaped guiding fit between the ear blade 2 and the tool body 1, allowing the ear blade 2 to move outwards and upwards or inwards and downwards relative to the tool body 1. Initially, the two ear blades 2 are positioned lower relative to the tool body 1 under their own weight, with a small distance between them.

[0045] Understandably, the drive cylinder 5 can be configured as any one of a hydraulic cylinder, a pneumatic cylinder, or an electric cylinder.

[0046] It is understandable that when there are multiple drive cylinders 5, the multiple drive cylinders 5 are arranged side by side, and the output shafts are all vertically downward and are jointly set on the tool body 1. The multiple drive cylinders 5 can synchronously drive the tool body 1 to move in the vertical direction, which helps to improve the stability of the tool body 1 when moving and the uniformity of force when bending the metal sheet.

[0047] It is understandable that the cross-sectional shape of the guide rail 101 can be set to an inverted T-shape, and the shape of the first slide groove 205 is set to an inverted T-shape accordingly. Thus, through the restriction of the T-shaped structure, the ear knife 2 only has the sliding degree of freedom extending along the guide rail 101.

[0048] During use, because the working principle of the ear cutter 2 relies on pre-avoiding the already formed flange, operators need to leave a safety gap when placing the metal sheet. This gap is usually 5-8mm. Without high-precision positioning assistance, manual placement is very likely to cause the center of the metal sheet to shift. According to production data, the probability of the shift exceeding 2mm is as high as 35%. This positioning deviation will cause uneven stress during the bending process: when the gap on one side is smaller than the design value, the compressive force on that side will exceed 120% of the rated load, resulting in over-bending and material thinning; while on the other side, due to insufficient pressure, the bending angle may deviate from the design value by more than 3°. In addition, uneven stress will also accelerate the local wear of the cutter body 1 and ear cutter 2, shortening the service life of the cutter body 1 and ear cutter 2 by about 25%, increasing equipment maintenance costs and downtime.

[0049] Based on this, the metal sheet inward flanging bending device provided in this embodiment of the invention is further configured to include a centering mechanism, which is arranged to make the bending center of the metal sheet coincide with the symmetry center of the two ear blades 2. Thus, before bending the metal sheet, the bending center of the metal sheet and the symmetry center of the two ear blades 2 can be made to coincide, thereby enabling the metal sheet to be bent in a centered manner. When the bending center of the metal sheet coincides with the symmetry center of the ear blades 2, the forces acting on both sides of the metal sheet during bending can remain balanced. This symmetrical force state avoids situations where one side experiences excessive force and the other side insufficient force due to positioning deviation. This balanced force state allows the metal sheet to be bent in a centered manner, thereby ensuring that the bending angle, shape, etc., meet the design requirements, guaranteeing the bending effect and accuracy. Simultaneously, because the forces on both sides are uniform, the wear degree of each part of the cutter body 1 and the ear blades 2 tends to be consistent during operation, avoiding accelerated wear caused by excessive local force, fundamentally guaranteeing the service life of the cutter body 1 and the ear blades 2.

[0050] Furthermore, the centering mechanism is configured to include a friction plate 301 and a symmetrical component 302. The friction plate 301 is disposed on the rear side wall of the tool body 1 and can be detachably connected to the tool body 1 by bolts. The surface of the friction plate 301 is vertically arranged. On the outer side wall of each ear cutter 2, a first mounting hole 206 is provided near the bottom. The first mounting hole 206 extends horizontally in the left and right direction. A push rod 303 is slidably inserted into each first mounting hole 206. The first mounting hole 206 has a stepped hole structure with the large end facing inward. The push rod 303 has a stepped rod structure with the large end facing inward. When installed, the push rod 303 can form a stop fit between its own step and the step of the first mounting hole 206, thereby limiting the maximum distance that the push rod 303 can move outward.

[0051] In each first mounting hole 206, an adjusting rod 304 is also inserted inside the top rod 303. The adjusting rod 304 extends horizontally in the left-right direction and has a first horizontal rod segment, a vertical rod segment, and a second horizontal rod segment connected sequentially and vertically. During installation, the adjusting rod 304 is slidably inserted into the first mounting hole 206 through the first horizontal rod segment. A first elastic element is provided between the top rod 303 and the adjusting rod 304. The first elastic element can be set as a first compression spring 305. During installation, the first compression spring 305 is placed horizontally in the large end of the first mounting hole 206, with its inner end located on the end of the first horizontal rod segment and its outer end located on the large end of the top rod 303. The second horizontal section is threaded with an intermediate sleeve 306; friction rings 307 are fixedly sleeved at both ends of the intermediate sleeve 306, and the friction rings 307 can form a friction transmission engagement with the friction plate 301; the symmetrical component 302 is configured to make the two push rods 303 symmetrically set about the symmetrical center of the two ear blades 2; initially, neither of the two friction rings 307 is in contact with the friction plate 301, and at the same time, under the action of the first compression spring 305, the step of the push rod 303 and the step of the first mounting hole 206 form a stop engagement, thereby limiting the maximum distance of the push rod 303 to move outward, and the small end of the push rod 303 extends out of the ear blade 2 so as to form a stop engagement with the metal plate.

[0052] To ensure that the push rod 303 and the adjusting rod 304 can only slide left and right in the horizontal direction, they can be configured such that the first mounting hole 206, the push rod 303, and the first horizontal section are all square structures, thereby restricting the rotation of the push rod 303 under the action of the square structure; alternatively, the large end of the first mounting hole 206 can be configured as a spline-like groove structure, and the large end of the push rod 303 and the first horizontal section can be configured as spline-like protrusion structures, thereby restricting the rotation of the push rod 303 through the spline engagement between the large end of the push rod 303 and the large end of the first mounting hole 206, and restricting the rotation of the adjusting rod 304 through the spline engagement between the first horizontal section and the large end of the first mounting hole 206.

[0053] Initially, the two ear blades 2 are positioned lower than the main body 1 under their own weight, with a small gap between them. The centering mechanism is symmetrical, and its center of symmetry coincides with the center of symmetry of the two ear blades 2. During use, the metal sheet is first placed on the frame 4. Due to the center offset caused by manual placement of the metal sheet, the metal sheet may be biased to the left or right. Taking the metal sheet biased to the right as an example...

[0054] The drive cylinder 5 is activated, and its output shaft extends, synchronously driving the cutter body 1 downward. Simultaneously, the cutter body 1 drives the friction plate 301 and the two ear cutters 2 downward. When the two ear cutters 2 contact the metal plate, as the cutter body 1 continues to move downward, the two ear cutters 2 move upward and outward synchronously through the sliding engagement between the first groove 205 and the guide rail 101. While increasing the distance between the two ear cutters 2, under the action of the first compression spring 305, the push rod 303 moves synchronously with the ear cutters 2. Because the metal plate is biased to the right, the position... The push rod 303 on the left side will first contact the bent side wall of the metal plate. During this process, the intermediate sleeve 306 and the two adjusting rods 304 remain stationary. After the push rod 303 on the left side contacts the bent side wall of the metal plate, as the cutter body 1 continues to move downward, the push rod 303 on the left side remains stationary due to the constraint of the bent side wall of the metal plate. At this time, since the ear cutter 2 is still moving outward, the push rod 303 on the left side will insert into the first mounting hole 206 relative to the ear cutter 2, and simultaneously compress the first compression spring 305 on the left side.

[0055] After the first compression spring 305 on the left is compressed, it synchronously drives the intermediate sleeve 306 and the two adjusting rods 304 to move to the right, thereby compressing the first compression spring 305 on the right. This keeps the two first compression springs 305 in a state of approximately uniform compression. During this process, the push rod 303 on the right moves outward synchronously with the ear knife 2 under the combined action of the stop formed with the first mounting hole 206 and the first compression spring 305 on the right. It may or may not contact the bent sidewall of the metal plate. When it contacts the bent sidewall of the metal plate, because the compression of the first compression spring 305 is small at this time, the force it exerts on the bent sidewall of the metal plate through the push rod 303 is small and cannot overcome the metal plate. The maximum static friction between the metal plate and the frame 4 is maintained, and the metal plate remains stationary. As the ear cutter 2 continues to move outward, both push rods 303 remain stationary due to the constraint of the bent sidewall of the metal plate. Therefore, the push rods 303 will continue to insert into the first mounting hole 206 relative to the ear cutter 2, simultaneously compressing the two first compression springs 305. Since the deformation of the two first compression springs 305 is consistent, even if the force of the first compression springs 305 pushing the bent sidewall of the metal plate through the push rods 303 can overcome the maximum static friction between the metal plate and the frame 4, the metal plate remains stationary because the forces of the two first compression springs 305 pushing the bent sidewall of the metal plate through the push rods 303 are opposite in direction and the same in magnitude.

[0056] As the intermediate sleeve 306 moves, when it reaches the friction contact between the friction ring 307 and the friction plate 301 on the left side, the tool body 1 continues to move downwards, synchronously driving the friction plate 301 downwards. The friction plate 301, through frictional contact with the friction ring 307 on the left side, drives the intermediate sleeve 306 to rotate. The intermediate sleeve 306, through its threaded engagement with the two adjusting rods 304, synchronously drives the two adjusting rods 304 away from each other, simultaneously compressing the two first compression springs 305. At this time, the push rod 303 on the left side remains stationary due to the constraint of the bent sidewall of the metal plate, while the push rod 303 on the right side is in contact with the first mounting hole 206. Under the combined action of the stop and the first compression spring 305 on the right, the metal plate moves synchronously to the right with the ear knife 2. It may continue to contact the bent sidewall of the metal plate or it may not. When it continues to contact the bent sidewall of the metal plate, since the deformation of the two first compression springs 305 is the same, even if the force of the first compression spring 305 pushing the bent sidewall of the metal plate through the push rod 303 can overcome the maximum static friction between the metal plate and the frame 4, the metal plate remains stationary because the forces of the two first compression springs 305 pushing the bent sidewall of the metal plate through the push rod 303 are opposite in direction and the same in magnitude.

[0057] When the cutter body 1 moves to the bottom and overlaps with the two ear blades 2, under the action of the symmetry component 302, the two push rods 303 are symmetrically set about the center of symmetry of the two ear blades 2. Both first compression springs 305 are released, driving the intermediate sleeve 306 and the two adjusting rods 304 to move to the left and return to the initial position. At this time, since the distance between the two adjusting rods 304 is larger than initially, the compression of the first compression springs 305 is greater than initially, and the first stage of force storage of the two first compression springs 305 is completed. Then the drive cylinder 5 is started, the output shaft of the drive cylinder 5 retracts, and synchronously drives the cutter body 1 to move upward. The cutter body 1 simultaneously drives the friction plate 301 and the two ear blades 2 to move upward. Under the action of their own weight, the two ear blades 2 move downward and inward relative to the cutter body 1 until they move to the initial position relative to the cutter body 1.

[0058] When the push rod 303 on the right side contacts the bent sidewall of the metal plate during the above process, and the force of the first compression spring 305 on the left side pushing the bent sidewall of the metal plate through the push rod 303 is greater than the maximum static friction between the metal plate and the frame 4, the above process is repeated. When the push rod 303 on the left side contacts the bent sidewall of the metal plate, as the cutter body 1 continues to move downward, the push rod 303 on the left side remains stationary under the constraint of the bent sidewall of the metal plate. At this time, since the ear cutter 2 is still moving outward, the push rod 303 on the left side will insert into the first mounting hole 206 relative to the ear cutter 2, and simultaneously compress the first compression spring 305 on the left side. Under the action of the first compression spring 305 on the left side, the push rod 303 on the left side can drive the metal plate to move to the left, thereby achieving centering.

[0059] When the push rod 303 on the right side is not in contact with the bent sidewall of the metal plate during the above process, the above process is repeated. After multiple stages of force accumulation, the compression of the first compression spring 305 continuously increases until its thrust on the bent sidewall of the metal plate through the push rod 303 is greater than the maximum static friction between the metal plate and the frame 4. When the push rod 303 on the left side contacts the bent sidewall of the metal plate again, as the cutter body 1 continues to move downward, the push rod 303 on the left side remains stationary under the constraint of the bent sidewall of the metal plate. At this time, since the ear cutter 2 is still moving outward, the push rod 303 on the left side will insert into the first mounting hole 206 relative to the ear cutter 2, and simultaneously compress the first compression spring 305 on the left side. Under the action of the first compression spring 305 on the left side, the push rod 303 on the left side can drive the metal plate to move to the left, thereby achieving centering.

[0060] It should be noted that when replacing metal plates of different sizes, if the weight of the replaced metal plate is greater than that of the previous metal plate, the increased weight of the metal plate increases the contact pressure between it and the frame 4, thereby increasing the maximum static friction between the metal plate and the frame 4. Therefore, in actual operation, the above process is repeated normally, allowing the first compression spring 305 to continue to store force until the pushing force of the push rod 303 on the bent sidewall of the metal plate is greater than the maximum static friction between the metal plate and the frame 4. Then, when one side of the push rod 303 contacts the bent sidewall of the metal plate again, as the cutter body 1 continues to move downward, the push rod 303 remains stationary due to the constraint of the bent sidewall of the metal plate. At this time, since the ear cutter 2 is still moving outward, the push rod 303 will insert into the first mounting hole 206 relative to the ear cutter 2, simultaneously compressing the first compression spring 305 on the same side. Under the action of the first compression spring 305 on the same side, the push rod 303 on one side can drive the metal plate to one side, thereby achieving centering.

[0061] Similarly, when the weight of the replaced metal plate is less than the weight of the previous metal plate, the reduced weight of the metal plate decreases the contact pressure between it and the frame 4, thus reducing the maximum static friction between the metal plate and the frame 4. Therefore, in actual operation, before moving the tool body 1, the intermediate sleeve 306 is rotated first. The intermediate sleeve 306, through the threaded engagement with the two adjusting rods 304, synchronously drives the two adjusting rods 304 to move closer together, simultaneously releasing the two first compression springs 305, thereby returning the adjusting rods 304 to their initial positions on the intermediate sleeve 306. Then, the above process is repeated normally, causing the first compression springs 305 to... The new force is accumulated until the thrust of the push rod 303 on the bent sidewall of the metal plate is greater than the maximum static friction between the metal plate and the frame 4. Then, when the push rod 303 on one side contacts the bent sidewall of the metal plate again, as the cutter body 1 continues to move downward, the push rod 303 on one side remains stationary under the constraint of the bent sidewall of the metal plate. At this time, since the ear cutter 2 is still moving outward, the push rod 303 on one side will insert into the first mounting hole 206 relative to the ear cutter 2, and simultaneously compress the first compression spring 305 on the same side. Under the action of the first compression spring 305 on the same side, the push rod 303 on one side can drive the metal plate to move to one side, thereby achieving centering.

[0062] Furthermore, the symmetrical component 302 is configured to include a push rod 3021, with each ear cutter 2 equipped with a push rod 3021. At least one ear plate 207 is fixedly mounted on the rear side wall of each ear cutter 2. The push rod 3021 penetrates the ear plate 207 during installation and can slide vertically. The top end of the push rod 3021 can form a stop engagement with the cutter body 1, allowing the push rod 3021 to slide downward. A wedge-shaped hole 3031 is provided on the small end side wall of each push rod 303, with the wedge-shaped hole 3031 inclined outward and downward simultaneously. A wedge-shaped head 30212 is fixedly mounted at the bottom of each push rod 3021, with the bottom of the wedge-shaped head 30212 being a wedge surface, also inclined outward and downward simultaneously. When the push rod 3021 moves downward, the wedge-shaped head 30212 inserts into the ear cutter 2, and then, through the wedge surface guide engagement with the wedge-shaped hole 3031, drives the push rod 303 to move inward, thereby enabling... The two push rods 303 are symmetrically arranged about the center of symmetry of the two ear blades 2. Thus, by releasing the first compression spring 305, the intermediate sleeve 306 and the two adjusting rods 304 are driven back to the initial position. To achieve the reset of the push rod 3021, the push rod 3021 is connected to the ear blade 2 through the second elastic element. The second elastic element can be set as the second compression spring 3022. When installed, the second compression spring 3022 is sleeved on the push rod 3021 and is located above the ear plate 207, forming a stop engagement with the ear plate 207. A retaining ring 30211 is threaded onto the push rod 3021. The retaining ring 30211 is located above the second compression spring 3022 and forms a stop engagement with the second compression spring 3022. During the downward sliding of the push rod 3021, the second compression spring 3022 is compressed synchronously. During the upward movement of the cutter body 1, the second compression spring 3022 is released, and synchronously, the push rod 3021 is moved to the initial position through the retaining ring 30211.

[0063] When the ear blade 2 has multiple ear plates 207, the multiple ear plates 207 are arranged side by side in the vertical direction. During installation, the push rod 3021 passes through all the ear plates 207 simultaneously. Under the constraint of the multiple ear plates 207, the push rod 3021 can slide stably in the vertical direction. As an example, when the ear blade 2 has two ear plates 207, the two ear plates 207 are arranged alternately in the vertical direction.

[0064] In a further embodiment, to improve the stability of the ear cutter 2 when sliding along the guide rail 101, at least one second mounting hole 208 is vertically opened on the rear side wall of each ear cutter 2. The second mounting hole 208 is also connected to the first sliding groove 205. A tensioning shaft 201 is inserted into the second mounting hole 208. At least one elastic ring 202 is sleeved on the tensioning shaft 201. The elastic ring 202 can form a stop engagement with the guide rail 101 to increase the contact normal pressure between the ear cutter 2 and the guide rail 101. This can improve the sliding stability of the ear cutter 2 on the guide rail 101 by increasing the friction between the ear cutter 2 and the guide rail 101.

[0065] In a further embodiment, each ear blade 2 has three tensioning shafts 201 inserted into it, and correspondingly, each ear blade 2 has three second mounting holes 208, which are arranged at intervals along a direction parallel to the first sliding groove 205. Each second mounting hole 208 has one tensioning shaft 201 inserted into it, thereby improving the uniformity of tension between the ear blade 2 and the guide rail 101 through the elastic rings 202 on the three tensioning shafts 201.

[0066] In other embodiments, to improve the stability of the ear blade 2 when sliding along the guide rail 101, a second sliding groove 1012 is provided on the outer side wall of the guide rail 101, and the second sliding groove 1012 is parallel to the guide rail 101; a third mounting hole 209 is provided on the outer side wall of each ear blade 2, the third mounting hole 209 is perpendicular to the first sliding groove 205 and communicates with the first sliding groove 205, a countersunk groove is provided at the outer end of the third mounting hole 209, a screw 203 is inserted into the third mounting hole 209, the second sliding groove 1012 is provided on the outer side wall of the guide rail 101, the second sliding groove 1012 is parallel to the guide rail 101, the screw 203 passes through the through hole 1011 during installation and is slidably inserted into the second sliding groove 1012, thereby better guiding the sliding of the ear blade 2.

[0067] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0068] The above-described embodiments are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention.

Claims

1. A metal sheet inward flanging bending device, characterized in that, The internal flanging bending device for metal sheets includes: The main body of the cutting tool can move vertically; Two ear blades are symmetrically arranged on the left and right sides of the cutter body. The ear blades form a wedge-shaped guide fit with the cutter body and can move outward and upward or inward and downward relative to the cutter body. The centering mechanism is configured to make the bending center of the metal sheet coincide with the symmetry center of the two ear blades; The centering mechanism includes a friction plate and a symmetrical assembly. The friction plate is mounted on the cutter body. Each ear cutter is fitted with a push rod and an adjusting rod. The push rod can slide along the direction of the two ear cutters and can both form a stop with the ear cutter and extend out of the ear cutter. On the outer side wall of each ear cutter, near the bottom, there is a first mounting hole. The first mounting hole extends in the left and right direction. The push rod is slidably inserted into the first mounting hole. The first mounting hole has a stepped structure with the large end facing inward. The push rod has a stepped rod-like structure with the large end facing inward. When the push rod is installed, it can form a stop fit between its own step and the step of the first mounting hole, thereby limiting the maximum distance that the push rod can move outward. In each first mounting hole, an adjusting rod is inserted into the inner side of the top rod. The adjusting rod extends horizontally in the left-right direction and has a first horizontal rod segment, a vertical rod segment, and a second horizontal rod segment connected sequentially and vertically. During installation, the adjusting rod is slidably inserted into the first mounting hole through the first horizontal rod segment. A first compression spring is provided between the top rod and the adjusting rod. During installation, the first compression spring is placed horizontally in the large end of the first mounting hole, with its inner end located on the end of the first horizontal rod segment and its outer end located on the large end of the top rod. An intermediate sleeve is threaded onto both second horizontal segments. Friction rings are fixedly sleeved at both ends of the intermediate sleeve, and the friction rings can form a friction transmission engagement with the friction plate. The symmetrical components are configured to make the two top rods symmetrically arranged about the symmetrical center of the two ear blades. Initially, neither of the two friction rings is in contact with the friction plate. At the same time, under the action of the first compression spring, the step of the top rod and the step of the first mounting hole form a stop engagement, thereby limiting the maximum distance the top rod can move outward. The small end of the top rod extends out of the ear blade to form a stop engagement with the metal plate. The symmetrical assembly includes push rods, each ear cutter is provided with a push rod, the push rod can slide in the vertical direction, and can form a stop engagement with the cutter body and a wedge-shaped guide engagement with the push rod, and is connected to the ear cutter through a second elastic element.

2. The metal sheet inward flanging bending device according to claim 1, characterized in that, The second elastic element is the second compression spring.

3. The metal sheet inward flanging bending device according to claim 1, characterized in that, Guide rails are detachably mounted on both the left and right sides of the cutter body; the ear cutter is slidably sleeved on the guide rails.

4. The metal sheet inward flanging bending device according to claim 3, characterized in that, Each ear cutter is fitted with a tensioning shaft, and each tensioning shaft is fitted with at least one elastic ring. The elastic ring can form a stop engagement with the guide rail to increase the contact pressure between the ear cutter and the guide rail.

5. The metal sheet inward flanging bending device according to claim 4, characterized in that, Each ear cutter contains three tensioning shafts.

6. The metal sheet inward flanging bending device according to claim 3, characterized in that, Each ear cutter also has a screw inserted inside, which is slidably inserted into the guide rail.

7. The metal sheet inward flanging bending device according to claim 3, characterized in that, The guide rail is detachably connected to the cutter body via a nut.

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