KR100629010B1 - manufacturing process of short pipe for a vibration prevention bracket - Google Patents

Abstract

The present invention relates to a device for producing a single pipe for a dustproof bracket for producing a single pipe with a roundness by cutting, bending, and forming a coiled iron sheet in one press by configuring a cutting, bending, and forming apparatus in a mold. will be.

That is, the base 12 is fixed to the upper mounting plate 11 mounted on the lower end of the press with a plurality of mounting pieces 14, and the upper mounting plate 13 mounted on the upper end of the press P is formed on the upper portion thereof. A bending device 30 each configured of a lower bending mold 30b having an upper bending mold 30a and a bending block 32 at a center between the base 12 and the upper mounting plate 13; A cutting device 20 each composed of an upper cutting mold 20a having a cutting punch 21 for cutting the coil iron plate 4 and a lower cutting mold 20b having a cutting hole 22a; The upper mold 40a and the lower mold 44 having the upper mold 41 to seat the bent “U” -shaped bending iron plate 2 to form the “O” shaped end pipe 1 are provided. Each of the forming apparatuses 40 constituted by the lower molding mold 40b provided therein constitutes a manufacturing apparatus 10 for manufacturing the coil iron plate 4 into the short pipe 1.

Cutting device, bending device, forming device, short pipe, iron plate, cutting punch, bending punch, dustproof port

Description

Manufacturing apparatus of short pipe for dustproof bracket

1 is a manufacturing process block diagram showing an embodiment of the present invention

2 is a modified view of the product according to the manufacturing process showing an embodiment of the present invention

Figure 3 is a block diagram of the product mounted on the lower mold according to the manufacturing procedure showing a preferred embodiment of the present invention

Figure 4 is a block diagram of a manufacturing apparatus showing a preferred embodiment of the present invention

       (A) is a block diagram of the upper and lower molds separated.

       (B) is a block diagram of the upper and lower molds mounted and fastened.

5 is a configuration diagram showing the form of a preferred cross-section of the present invention.

Figure 6 is an exploded perspective view showing the configuration of a preferred cutting device of the present invention.

Figure 7 is an exploded perspective view showing the configuration of a preferred bending device of the present invention.

8 is an exploded perspective view showing the configuration of a preferred molding apparatus of the present invention.

Figure 9 is an operating state diagram showing one embodiment of a preferred cutting device of the present invention.

10 is an operating state diagram showing an embodiment of a preferred bending device of the present invention.

11 is an operating state diagram showing an embodiment of a preferred molding apparatus of the present invention.

Figure 12 is a use state showing a preferred embodiment of the present invention.

□ Explanation of the main symbols used in the main part of the drawing □

1: Short pipe 2: Bending iron plate

3: iron plate 4: coil iron plate

10: manufacturing apparatus 11: bottom mounting plate

12: base 13: upper mounting plate

15: guide pin 20: cutting device

20a: upper cutting mold 20b: lower cutting mold

21: Cutting punch 21a: Rib

22: lower subplate 22a: cutting hole

23: lower control plate 23a: discharge hole

24: discharge space 25: guide plate

25a: Guide groove 26: Upper cutting plate

26a: upper subsidiary plate 26b: coupling hole

26c: Punch Guide 27: Top Seating Plate

27a: elastic body 28: locking pin

28a: latching hole 29: coupling pin

29a: mounting hole 30: bending device

30a: upper bending mold 30b: lower bending mold

31: bending punch 31b: bending surface

32: Bending block 32a: Milpin

32b: bending groove 33: bending frame

33a: Auxiliary block 33b: Built-in groove

34: stopper 35: information board

36: subplate 37: operation block

37a: discharge pin hole 37b: elastic pin hole

38: iron plate seat 39: discharge pin

39a: elastic pin 40: molding apparatus

40a: upper molding mold 40b: lower molding mold

41: upper mold 41a: upper mold groove

41b: Molding groove 41c, 44c: Tightening groove

41d: Slope 42: Upper auxiliary frame

42c, 45c: binding protrusion 43: upper fixing plate

44: lower molding frame 44a: lower molding groove

44b: Guide protrusion 45: Lower auxiliary frame

46: bottom fixing plate 47: side plate

The present invention relates to an apparatus for manufacturing a short pipe constituting a bracket for mounting and fixing a vibration isolator mounted to reduce the vibration of the vehicle, and more particularly, a cutting, bending, forming apparatus each configured to a set of molds The present invention relates to an apparatus for manufacturing a single pipe for an anti-vibration bracket for cutting and bending a coiled iron plate in a press to produce a single pipe having a roundness.

The vehicle's anti-vibration bracket is installed by fixing the engine to the frame of the vehicle to prevent vibration from the engine and to protect the engine from the impact from the outside of the vehicle. Conventionally, conventionally manufactured pipes are manufactured by selecting a required diameter from a conventionally manufactured pipe and cutting it to a certain length. This is to cut the pipe and then chamfer the edge of the cut part. In order to make pipes more precise, productivity has been reduced due to post-processing, such as precision cleaning, and production costs have increased.

In view of these problems, in recent years, a single pipe is produced by another manufacturing method using raw materials instead of pipes, but this can also be confirmed by Utility Model Application No. 1999-0007480. Due to the construction, not only the production cost is reduced by the work for the production of the steel plate, but also it is difficult to produce the round pipe of the required roundness due to the joining process of the joining protrusion and the joining groove, which reduces the quality of the product. As can be seen through 2004-0002341, the production and production of dedicated machines can improve the productivity and quality, but in the production system of small quantity production system as in modern times, it is impossible to respond to the specification change of products. As the investment cost for production increases, The complex Another problem is though related companies, including the cost of the product increased to a situation which does not provide much resolution.

Therefore, in the present invention, to solve all the problems described above, by cutting, bending, and forming a device in a set of molds, the coil iron plate is cut, bent, and formed in one press. In addition to improving productivity, it is possible to manufacture single pipes with various specifications according to the product dimension change by changing parts or mounting position without changing the whole device. will be.

1 is a manufacturing process block diagram showing a preferred embodiment of the present invention, Figure 2 is a modified view of the product according to the preferred embodiment of the present invention, Figure 3 is a preferred embodiment of the present invention Figure 4 is a block diagram of the product mounted on the lower mold according to the manufacturing procedure shown, Figure 4 is a block diagram of a manufacturing apparatus showing a preferred embodiment of the present invention (A) is a block diagram of the upper and lower molds are separated (b) ) Is a configuration diagram of a state in which the upper and lower molds are mounted and fastened, FIG. 5 is a configuration diagram showing a preferred cross-sectional shape of the present invention, and FIG. 6 is an exploded perspective view showing the configuration of a preferred cutting device of the present invention. 7 is an exploded perspective view showing the configuration of a preferred bending device of the present invention, Figure 8 is an exploded perspective view showing the configuration of a preferred molding apparatus of the present invention, Figure 9 is an embodiment of a preferred cutting device of the present invention 10 is an operation state diagram showing an embodiment of a preferred bending device of the present invention, Figure 11 is an operating state diagram showing an embodiment of a preferred molding apparatus of the present invention, Figure 12 is a present invention As a state diagram showing a preferred embodiment of the present invention through this will be described in detail the configuration and operation of the apparatus for producing the anti-vibration bracket for pipe provided in the present invention.

In the manufacturing method of producing the single pipe | tube 1 using the press P;

The coil iron plate 4, which maintains a constant thickness and width, is mounted on one side of the press P and injected into the guide groove 25a provided on the lower cutting mold 20b of the manufacturing apparatus 10. (P) a cutting step of cutting the length of the cutting apparatus 21 by the cutting punch 21 and the cutting holes 22a by the required length to form the iron plate 3; Automatically seated on the upper part of the lower bending mold 30b of the manufacturing apparatus 10 integrally composed of the iron plate 3 cut to a predetermined length required, and then the bending block of the bending apparatus 30 by a press (P) operation. A bending step of forming the iron plate 3 into the “U” -shaped bending iron plate 2 by the 32 and the bending punch 31; It is seated on the upper part of the lower molding mold 40b of the manufacturing apparatus 10 having the bending steel plate 2 integrally formed thereon, and then pressed to the lower molding frame 44 and the upper molding frame 41 of the molding apparatus 40 by pressing. A process for manufacturing the anti-vibration bracket bracket single pipe (1) mainly applied to the vehicle only through the molding process for forming the short pipe (1) by this is made through the manufacturing apparatus of the following anti-vibration bracket bracket.

The lower mold 10b and the upper mold 10a are divided into upper and lower ends of the press P main body, respectively, and the upper mold 10a is separated and coupled to the lower mold 10b according to the operation of the press P. In the manufacturing apparatus of the short pipe | tube comprised by a metal mold | die;

As shown in FIG. 5, the base 12 having a predetermined width is connected to a plurality of mounting pieces 14 and fixed to a lower portion of the lower mounting plate 11 mounted on the lower end of the press to form a predetermined distance. An upper bending mold 30a having a bending punch 31 in the center between the base 12 and the upper mounting plate 13 is formed by forming an upper mounting plate 13 fixed to the upper end of the press P at an upper portion thereof. Forming a bending device 30 for bending the iron plate (3) each composed of a lower bending mold (30b) having a block 32, by injecting the coil iron plate (4) on one side of the iron plate (3) Cutting device 20 composed of an upper cutting mold 20a having a cutting punch 21 and a lower cutting mold 20b having a cutting hole 22a, and bending on the other side. The upper mold 41 to seat the "bending iron plate 2 of the shape (2) to form a" O "shaped short pipe (1) Manufacture of forming the coil iron plate (4) as a short pipe (1) by forming a molding apparatus 40 composed of the upper molding mold (40a) and the lower molding mold (40b) having a lower mold 44 Configure the device 10.

In this case, the cutting device 20 for cutting the coil iron plate 4 to produce the iron plate 3 having a predetermined length has a discharge hole 23a formed at the center of the base 12 as shown in FIG. 6. The lower auxiliary plate 23 is mounted with a plurality of discharge blocks 24a to form a discharge space 24 in which the iron plate tips 3a cut from the coiled iron plate 4 are accumulated, and a cutting hole 22a is formed at the center thereof. And a lower cutting mold 20b formed by mounting a lower cutting plate 22 having a plurality of guide plates 25 formed thereon with guide grooves 25a on the upper surface thereof to be symmetrical. ; The bottom surface of the upper mounting plate 13 is provided with a cutting punch 21 at the center thereof, and forms a plurality of seating holes 27b on which the elastic body 27a is seated outside, and is coupled to the mounting holes 29a formed at the corners. The upper mounting plate 27 equipped with the pins 29 is mounted, and the upper part of the upper cutting plate 26 is formed with a punch guide hole 26c at the center and a mounting hole 29a at the corner. After the auxiliary plate 26a is fastened, a plurality of locking pins 28 are fastened to the engaging holes 28a of the upper seating plate 27 and the fastening holes 28b of the upper cutting plate 26 by the elastic body 27a. An upper cutting mold 20a configured to maintain a predetermined distance while preventing separation between the upper seating plate 27 and the upper cutting plate 26 is generated.

And the bending device 30 for bending the cut iron plate 3 is cut in the cutting device 20 also fastened the punch 31 to the lower mounting plate 13 as shown in Figure 7 with a punch fixing plate 31a An upper bending mold 30a fixed and configured; A coil is formed by mounting a plurality of pin holes 12a in the base 12 and a discharge pin hole 37a having a coil spring S embedded therein, and an operation block 37 having a plurality of elastic pin holes 37b formed therein. The discharge pin 39 and the elastic pin 39a are respectively seated on the upper part of the spring S, and the bent block 32 into which the mill pin 32a is inserted is built together with the auxiliary blocks 33a on both sides. The subplate 36 and the plurality of guide holes 35a formed at the center of the plate mounting piece 38 and the lower side of the bending frame 33 to which the stoppers 34 are mounted on one side are formed. The guide plate 35 is attached to the lower bent mold 30b formed by mounting the upper portion of the base 12 so that the pinhole 12a and the guide hole 35a coincide with each other.

In addition, the forming apparatus 40 for forming the bent iron sheet 2 into the forming end pipe 1 has an upper portion in which a forming guide groove 41b is formed at the lower end of the upper forming groove 41a formed at the center as shown in FIG. 8. An upper molding mold 40a formed by fixing the molding mold 41 to the lower surface of the upper mounting plate 13 by an upper fixing plate 43; The side plate 47 is attached to the front surface of the lower molding frame 44 having the lower forming groove 44a formed on the upper surface together with the guide protrusion 44b and connected to the lower fixing plate 46 on the upper surface of the base 12. It is formed into a lower molding mold (40b) configured by mounting.

At this time, a plurality of binding grooves (41c, 44c) formed on the front of the forming mold (41, 44) divided into upper and lower, respectively, the auxiliary molding frame divided into upper and lower portions protruding the plurality of binding protrusions (42c, 45c) The upper and lower auxiliary molds 42 and 45 formed to have a width corresponding to the changed length when the length of the short pipe 1 to be changed is configured by binding the 42 and 45, respectively, to the upper and lower molds 41. (44) A binder was formed on the entire surface to form a single tube 1 of a required length.

The apparatus 10 for manufacturing a single pipe for the anti-vibration bracket which is configured as described above is shown in FIGS. 2 and 3 while the manufacturing processes shown in FIG. 1 are made according to the input of materials (iron plate) while the respective apparatuses operate simultaneously. As described above, the material is deformed for each device;

First, as shown in the use state diagram shown in FIG. 12, the coil 10 is coil-plate feeder M mounted on one side of the press P and separately mounted to the press P main body of the manufacturing apparatus 10 of the present invention. (4) is supplied to the manufacturing apparatus 10 and injected into the upper portion of the lower cutting mold 20b of the cutting device 20, as shown in Figure 3 and then the press (P) is operated to cut the cutting device 20 A part of the coil iron plate 4 is cut by the punch 21 to form the iron plate 3, and a cutting process is performed. After that, the coil iron plate 4 is operated again to cut the coil iron plate 4 into a cutting device ( 20) When the coiled iron plate 4 pushes the iron plate (3) to be automatically seated on the upper portion of the lower bending mold (30b) of the bending device 30, at this time if the press (P) to operate again the lower bending mold (30b) Iron plate (3) seated on the iron plate 3 is bent "U" shape by the bending punch 31 and the bending block 32 of the bending device 30 At the same time the bending process to be bent to the iron plate (2) is made and the cutting process is made in the bending device (30), at this time, using the separate transfer device or the operator to form the bending device (2) formed in the bending process (40) At the same time seating on the lower mold (40b) of the bottom and at the same time operating the coil iron sheet feeder (M) and then operating the press (P) as well as the above cutting and bending process is made of the lower mold (40b) The bending iron plate 2 seated on the molding unit 40 is molded into the short pipe 1 by the upper mold 41 and the lower mold 44 of the molding apparatus 40, and the molding process is performed.

In addition, each process made as described above is made by each device that is configured and operated simultaneously in the manufacturing apparatus 10, the operation of each of these devices with the configuration in more detail as follows.

First, as shown in FIG. 9, the cutting device 20 uses the coil iron plate 4 as the upper part of the lower cutting plate 22 of the lower cutting mold 20b through the coil iron plate supply device M. When seated, it is installed in the guide groove 25a formed in the guide plate 25 mounted on the upper part of the lower cutting plate 22 so that the coil iron plate 4 is not only seated at the correct position but also the coil iron plate 4 during the cutting operation. ) Is to bend or to escape to the outside.

As described above, when the coil iron plate 4 is seated on the upper portion of the lower cutting plate 22 and then the press P is operated to lower the upper cutting mold 20a, the coupling pin 29 mounts the lower cutting plate 22. The upper cutting plate 26 is first inserted into the ball 29a and the distance is maintained by the length of the upper cutting plate 26 and the locking pin 28 by the elastic body 27a while the upper cutting plate 26 is in contact with the coil iron plate 4. The upper seating plate 27 was lowered, and the cutting punch 21 fixed to the upper seating plate 27 descends through the punch guide hole 26c while applying pressure to the coiled iron plate 4 while cutting holes ( The cutting operation is completed by cutting the width of 22a), and the iron plate tip 3a formed at this time is pushed into the discharge hole 23a to be discharged into the discharge space 24.

In this case, ribs 21a having a predetermined width are formed at both ends of the cutting punch 21 to prevent bending or breakage of the cutting punch 21, and at the same time, the cutting pressure is reduced by narrowing the cutting width to make cutting easier. By minimizing the amount of the tip 3a, it is possible to reduce material and improve productivity.

Then, when the upper cutting mold 20a is raised by operating the press P, the upper cutting plate 26 and the upper auxiliary plate 26a are lower cut by the elasticity of the elastic body 27a by the length of the locking pin 28. 22) the cutting punch 21 fixed to the upper seating plate 27 in the state of being in close contact with the upper plate 1 rises first to be separated from the cutting hole 22a of the lower cutting plate 22, and then the upper cutting mold 20a and the lower portion. The cutting mold 20b is separated and the cutting process is completed, so that the iron plate 3 located in the guide groove 25a of the guide plate 25 is prevented from being separated out even when the work is completed.

The bending device 30 is also automatically transferred by the coiled steel sheet 4, which is cut by the cutting device 20, by the coiled steel sheet feeder M, and is then bent into the bending frame of the lower bending mold 30b ( 33) It is seated on the upper side at this time can be accurately seated on the position of the iron plate (3) by the stopper 34 fixed to one side of the bending frame (33) and the iron plate mounting piece (38) mounted on the upper side of the bending frame (33). will be.

As described above, when the upper bending mold 30a is lowered by operating the press P while the iron plate 3 is seated on the lower bending mold 30b, the bending surface 31b of the bending punch 31 is first plated ( 3) the center of the iron plate (3) is lowered along with the pin (32a) while being in contact with the center, the lower surface of the iron plate (3) to the bent surface (32c) forming the bent groove (32b) of the bending block 32 The center of the iron plate 3 is bent as it is in contact, and then, due to the continuous lowering of the bending punch 31, the bending block 32 is also lowered so that a part of both sides of the center lower surface of the iron plate 3 is in contact with the auxiliary block 33a. After completing the bending operation and raising the upper bending mold (30a) by the elastic force of the coil spring (S) built into the operation block 37 mounted on the base 12, the discharge pin 39 and the elastic pin (39a) As the) rises, the bending block 32 and the mill pin 32a are raised to be transferred to the position before the operation, and the upper bending mold ( When 30a) is fully raised, the bent iron plate 2 on which the mill pin 32a is bent is separated from the bending groove 32b of the bending block 32 to facilitate the discharge of the bent iron plate 2.

In addition, the forming apparatus 40 for forming the bending iron plate 2 and the short pipe 1 seats the bending iron plate 2 in the lower forming groove 44a of the lower forming frame 44 formed in the lower forming mold 40b. When the upper molding die 40a is lowered by operating the press P, the inclined surface 41d which comes in contact with the inclined surface 41d of the forming guide groove 41b for maintaining a constant angle at both ends of the bent steel plate 2 is lowered. It is narrowed by the angle of the easy to be injected into the upper forming groove (41a), and easy to insert the guide projection (44b) of the lower forming mold 44, as well as the forming groove of the upper and lower forming molds (41, 44) The function of inducing the centers of the 41a and 44a to coincide with each other is to improve the roundness of the formed short pipe 1 so that the quality of the short pipe 1 is improved, and the front and rear surfaces of the lower mold 44 The side plate 47 to be mounted on the bent iron plate (2) during operation while making the mounting of the bent iron plate (2) easier In addition to preventing the separation of), it is to prevent the separation of the molded end pipe (1).

In addition, by forming the upper and lower auxiliary frame (42, 45) in front of the upper and lower forming mold (41, 44) to form the forming mold (41, 44) of the same length as the length of the short pipe (1) required by the molding apparatus ( It is to be able to produce the short pipe (1) of the required length without denaturing the components of the 40, wherein the binding grooves (41c, 44c) and auxiliary frame (42, 45) formed in the forming mold (41, 44) The binding protrusions 42c and 45c protruded to prevent the center points of the forming molds 41 and 44 and the auxiliary molds 42 and 45 from being changed during the operation, and the forming molds 41 and 44 of the forming apparatus 40. By changing the length of the short pipe 1 to be produced by forming the guide plate 25 of the cutting device 20 and the iron plate seating piece 38 of the bending device 30, Without changing the basic configuration and the reference point is to easily change only some parts to produce a shorter pipe (1) of more various lengths.

Each of the parts mounted on the upper and lower molds constituting the cutting device 20, the bending device 30, and the molding device 40 made as described above is usually attached to each other parts in order to more precisely and stably bond with each other. The standard pins are mounted and coupled to each other, which is a common joining method used for assembling molds, and the coil iron plate supplying device M and the manufacturing device 10 which continuously perform each process are performed in each device. The normal operation is to allow various parts of the sensing senses and limit switches to be automatically and continuously processed through an electric / electronic control system with an electric valve, which is a control method that can be used commonly in an automation system. It will be used to provide a separate control device by applying the specific description thereof will be omitted. (Not shown)

As described in detail above, the forming method and forming apparatus for the anti-vibration bracket bracket of the present invention constitutes a cutting, bending, and forming apparatus in a single mold to change the product without changing the entire apparatus without changing the whole apparatus. It is possible to manufacture single pipes with various specifications according to the dimensional change, and produce single pipes with precise roundness only by cutting, bending and forming coil coils in one press. The cutting, bending, and forming work processes are performed by only a short process that is performed, thereby improving productivity and rapidly producing high quality short pipes at low cost.

Claims (6)

The lower mold 10b and the upper mold 10a are divided into upper and lower ends of the press body P, and the lower mold 10b and the upper mold 10a are separated according to the operation of the press P. Combination of the cutting device 20, the bending device 30 and the molding device 40 by the mold to be maintained so as to maintain a constant distance between the base 12 and the upper mounting plate 11, each configured to be configured as a single device In the manufacturing apparatus of the end pipe for the anti-vibration port bracket characterized in that; A discharge space in which the iron plate tip 3a cut from the coil griddle 4 is accumulated by mounting the lower auxiliary plate 23 having the discharge hole 23a formed at the center of the base 12 as a plurality of discharge blocks 24a. The lower cutting plate 22 which forms the cutting hole 22a in the center, and mounted the symmetrical guide plates 25 in which the guide groove 25a was formed in the upper surface of the lower auxiliary plate (23) a plurality of seating holes provided with a lower cutting mold 20b configured to be mounted on the upper part, and a cutting punch 21 at the center of the lower surface of the upper mounting plate 13, and an elastic body 27a to the outside thereof; (27b) forms an upper seating plate (27) having coupling pins (29) in each of the mounting holes (29a) formed at the corners, and is mounted at the center of the punch guide hole (26c) and the corners at the bottom thereof. After fastening the upper subplate 26a to the upper cutting plate 26 on which the balls 29a are formed, The rim pin 28 is fastened to the engaging hole 28a of the upper seating plate 27 and the fastening hole 28b of the upper cutting plate 26 so that the gap between the upper seating plate 27 is generated by the elastic body 27a. A cutting device 20 formed of an upper cutting mold 20a configured to maintain a predetermined distance while preventing the upper cutting plate 26 from being separated; The upper bending mold 30a formed by fastening and fixing the bending punch 31 to the lower part of the upper mounting plate 13 by the punch fixing plate 31a, and a plurality of pinholes 12a are formed in the base 12, The discharge pin hole 37a having the coil spring S built therein and an operation block 37 having a plurality of elastic pin holes 37b formed thereon to discharge the pin 39 and the elastic pin 39a on the coil spring S. The seats are respectively seated, and the bent block 32 into which the mil pin 32a is inserted is built together with the auxiliary blocks 33a on both sides, and the iron plate seating piece 38 and the stopper 34 are mounted on one side, respectively. The pinhole 12a and the guide hole 35a are formed by binding the auxiliary plate 36 having the block mounting groove 36a formed at the center of the bending frame 33 and the guide plate 35 having the plurality of guide holes 35a formed therein. The bending device 30 formed of a lower bending mold 30b configured to be mounted on an upper portion of the base 12 so as to coincide therewith; The upper mold formed by connecting and fixing the upper mold 41 formed with the molding guide groove 41b to the lower end of the upper mold groove 41a formed at the center by connecting the upper fixing plate 43 to the lower surface of the upper mounting plate 13. The side plate 47 is attached to the mold 40a and the rear surface of the lower molding frame 44 formed with the guide protrusion 44b on the upper surface thereof, and the lower surface on the upper surface of the base 12. Apparatus for producing a single pipe for the anti-vibration bracket bracket, characterized in that each consisting of a molding device 40 formed of a lower molding mold (40b) configured by connecting and mounting with a fixed plate (46). The method of claim 1; The upper auxiliary frame 42 and the lower auxiliary frame protruding the plurality of binding protrusions 42c and 45c by forming a plurality of binding grooves 41c and 44c, respectively, in front of the upper mold 41 and the lower mold 44. An apparatus for manufacturing a single pipe for a dustproof bracket, characterized in that each of (45) is bound. delete delete delete delete

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