Concentric double disc steel band armoring machine

Abstract

A concentric double-disk steel belt armoring machine comprises a steel belt machine and a reverse machine, the reverse machine being located beside the steel belt machine frame. The steel belt machine comprises a steel belt machine frame, a wrapping head and a steel belt placing device mounted on the steel belt machine frame; the rotating axes of the wrapping head and the steel belt placing device are the same; the steel belt placing device comprises first and second steel belt placing devices, which are located in the cage structure of the wrapping head; the first and second steel belt placing devices are arranged in sequence from back to front on the same axis and in the rear part of the wrapping head; the second steel belt placing device is fixed on an intermediate thread spool, and the first steel belt placing device is fixed on a first steel belt disk shaft; the intermediate thread spool and the first steel belt disk shaft are respectively connected with a tension control device and a driving motor; the axial positions of the first and second steel belt reverse disks of the reverse machine are respectively aligned with the first and second steel belt placing devices of the steel belt machine; and there is an upper belt path of the steel belt between the corresponding steel belt reverse disk and the steel belt placing device.

Description

Technical Field

[0001] This utility model belongs to the technical field of cable wrapping equipment, specifically a concentric double-disc steel strip armoring machine. Background Technology

[0002] A steel tape armoring machine is a specialized piece of equipment used in cable manufacturing. It is mainly used for wrapping a steel tape armor layer around the cable insulation layer to enhance the cable's mechanical strength and compressive strength.

[0003] Existing steel strip armoring machines mainly include double-disc semi-cut steel strip armoring machines and single-disc concentric steel strip armoring machines. Semi-cut steel strip armoring machines suffer from insurmountable drawbacks such as large rotational inertia, high centrifugal force, low speed, and low production efficiency. While single-disc concentric steel strip armoring machines solve the problems of large rotational inertia, high centrifugal force, and low speed, the single-layer oblique steel strip wrapping effect is far inferior to the double-layer overlapping wrapping effect in terms of tightness and roundness. Furthermore, both types of armoring machines suffer from poor stability in wrapping tension control, leading to large variations in wrapping pitch and overlap rate, affecting the quality of steel strip armoring. In addition, both types of armoring machines require frequent manual loading and unloading of the steel strip and reel changes, resulting in high labor intensity for employees and low production efficiency. Summary of the Invention

[0004] To address the problems of low production efficiency and inconvenient steel strip installation in existing steel strip wrapping machines, this utility model proposes a concentric double-disc steel strip armoring machine, the specific structure of which is described below.

[0005] A concentric double-disc steel strip armoring machine includes a steel strip machine. The structure of the steel strip machine includes a steel strip machine frame and a wrapping head and a steel strip placement device installed on the steel strip machine frame. The rotation axes of the wrapping head and the steel strip placement device are the same.

[0006] With the exit side of the steel strip machine as the front, the front of the wrapping head is the wrapping area. There is a steel strip exit path between the steel strip placement device and the wrapping area. The guide wheel group on the exit path, which is used to support and conduct the steel strip, is installed on the wrapping head.

[0007] The steel strip placement device includes a first steel strip placement device and a second steel strip placement device, which are located inside the wrapping head of the cage structure;

[0008] The first steel strip placement device and the second steel strip placement device are arranged sequentially from back to front on the same axis, and are located at the rear of the wrapping head;

[0009] The second steel strip placement device is fixed to the intermediate threading shaft, which has a tubular hollow section for cable passage. A first steel strip reel shaft is sleeved on the outside of the intermediate threading shaft via a bearing device, and the first steel strip placement device is fixed to the first steel strip reel shaft. The first steel strip reel shaft is sleeved on the wrapping head connecting shaft via a bearing device. The wrapping head is fixed to the wrapping head connecting shaft. The wrapping head connecting shaft is connected to the steel strip machine frame via a bearing device. The intermediate threading shaft, the first steel strip reel shaft, and the wrapping head connecting shaft are each connected to a corresponding drive motor via a transmission mechanism, and all three are equipped with braking devices.

[0010] Tension control devices (used to control the tension of the first and second steel strip placement devices) are also connected to the intermediate threading shaft and the first steel strip reel shaft, respectively.

[0011] It also includes a rewinding machine, which is located next to the steel strip machine frame;

[0012] The tape rewinding machine includes a tape rewinding machine frame and a tape rewinding machine motor and first and second steel tape rewinding reels mounted on it; the rotation axes of the two steel tape rewinding reels are parallel and parallel to the rotation axis of the wrapping head; the two steel tape rewinding reels are connected to the tape rewinding machine motor through a transmission device; the rotation shafts of the first and second steel tape rewinding reels are also connected to a tension control device;

[0013] The axial positions of the first and second steel strip rewind reels are aligned with the first and second steel strip mounting devices of the steel strip machine, respectively.

[0014] This invention further improves upon existing concentric steel strip armoring machines to obtain a concentric double-disc steel strip machine. Two steel strip placement devices (functioning the same as the steel strip reels) are fixed to their respective shafts, resulting in high structural stability. The steel strip is loaded using a rewinding machine. During loading, the starting end of the steel strip on the rewinding reel is connected to the steel strip placement device, and a drive motor rotates the device to wind the steel strip onto it. This structure eliminates the need for manual loading, unloading, and rewinding of the steel strip machine, reducing labor intensity and improving worker safety. The tension control device on the steel strip machine helps improve the wrapping quality, while the tension control device on the rewinding machine helps improve the tightness of the steel strip winding during loading.

[0015] In terms of structural implementation, the corresponding rotating shaft of the steel strip machine is a hollow tube assembly, which simplifies the transmission structure and improves structural reliability. The drive motors connected to the intermediate threading shaft and the first steel strip reel shaft are used to wind the reel onto the first and second steel strip mounting devices.

[0016] Furthermore, there is a steel belt feeding path between the corresponding steel belt rewinding reel and the steel belt placement device, and steel belt support rollers are installed on the feeding path. The steel belt support rollers on the feeding path are connected to the side of the steel belt machine frame; the wrapping head side roller is on the feeding path. This structure effectively limits the stability of the steel belt during feeding and avoids safety hazards such as belt skipping.

[0017] Furthermore, in the rewind machine, the rewind machine motor is a torque motor; the transmission device between the rotating shafts of the first and second steel strip rewind reels and the output shaft of the torque motor is a chain drive. The tension control device in the rewind machine is a magnetic powder brake mounted on the rewind machine frame; the magnetic powder brake is connected to the rotating shafts of the first and second steel strip rewind reels via a chain drive. With this structure, the rewind machine motor requires less work, and one motor can drive two rewind reels to meet the needs. The magnetic powder brake also uses a chain drive to brake the rotating shafts of the rewind reels, resulting in high transmission accuracy.

[0018] Furthermore, the tension control device in the steel strip machine is a magnetic powder brake; the intermediate threading shaft and the first steel strip reel shaft are respectively connected to a magnetic powder brake through a transmission mechanism.

[0019] Furthermore, multiple lifting plates are connected to the steel strip machine frame; at the far end of the main line side of the steel strip machine, there is a conduit for cable threading, which is connected to the steel strip machine frame via a fixed frame below the conduit. The structure of the conduit improves the stability during cable production and enhances the armor quality of the cables. The design of the lifting plates facilitates the transportation of the steel strip machine.

[0020] Furthermore, a protective plate is connected to the frame of the steel strip machine, and the wrapping head and steel strip placement device are located inside the protective plate; the protective plate has a threading hole through which the upper path of the steel strip passes. Since the steel strip machine and the rewinding machine have two working states, armored and upper, and especially the upper speed is very high, this structure can better limit the risk of strip breakage and strip slippage within the protection range of the protective plate.

[0021] During project implementation:

[0022] The steel strip placement device can refer to the existing steel strip reel design, except that the corresponding rotating shaft (such as the intermediate threading shaft corresponding to the second steel strip placement device) is used as the winding shaft of the reel, and fixed plates are installed on both sides of the winding part of the winding shaft to realize the function of the reel.

[0023] The drive motors for the intermediate threading shaft and the first steel strip reel shaft are servo motors, and the braking devices are brake discs and brake calipers. This combination provides good service life, braking effect, and maintainability. Similarly, the winding head connecting shaft also uses a servo motor as its drive motor, and a brake disc and brake caliper as its braking device.

[0024] The cage-type wrapping head can adopt the structural principle of existing wrapping heads. The side rollers of the wrapping head are used to support and guide the steel belt during the feeding process.

[0025] The bearings used in steel belt conveyors are equipped with grease nipple lubrication circuits, which facilitate automatic or periodic oiling.

[0026] Compared with the prior art, the main beneficial effects of this utility model are:

[0027] 1. This utility model installs two steel strip reel devices on the main shaft. When the motor drives the main shaft to rotate, it can generate two overlapping strip directions on the wire core, completing the overlapping armoring of two steel strips in one go, improving processing efficiency and ensuring stable wrapping effect.

[0028] 2. This utility model of a concentric double-disc steel strip armoring machine is reliable in operation, highly efficient, simple to operate, and can guarantee product quality. The tension of the strip is controlled by a servo motor, which can realize the automatic tracking process from full-disc tension to empty-disc tension. This solves the problem of uneven tension and missing strips in traditional steel strip machines, improves product quality and reliability, and increases efficiency.

[0029] 3. The concentric double-disc steel belt armoring machine of this utility model has a concentric winding mechanism with low centrifugal force, high speed and high safety performance; at the same time, the double-disc structure has the function of rewinding the belt, realizing the direct rewinding of the steel belt onto the steel belt disc, which solves the problems of frequent manual loading and unloading of discs and high labor intensity of disc changing.

[0030] 4. The concentric double-disc steel belt armoring machine of this utility model is designed with grease nipple lubrication circuit for each bearing, which facilitates automatic or periodic oiling, reduces the failure rate during equipment start-up, and improves the service life of the equipment. Attached Figure Description

[0031] Figure 1 This is an isometric view of the entire machine in this embodiment;

[0032] Figure 2 This is a cross-sectional view of the main shaft in this embodiment;

[0033] Figure 3 This is the front view of the tape rewind machine in this embodiment;

[0034] Figure 4 This is a schematic diagram of the wrapping head structure in this embodiment;

[0035] Figure 5 This is a schematic diagram (perspective) of the steel strip machine in this embodiment;

[0036] Figure 6 This is a schematic diagram of the internal structure of the steel strip machine in this embodiment (the first servo motor is omitted in the figure).

[0037] Figure 7 for Figure 6 A top-down view diagram;

[0038] In the diagram: 1. Wrapping head; 2. Steel strip machine frame; 3. Threading conduit; 4. Lower fixing frame of threading conduit; 5. Lifting plate; 6. Rewinding machine frame; 7. First steel strip rewinding reel; 8. Second steel strip rewinding reel; 9. Lifting eye bolt; 10. Upper reel guide wheel; 11. Intermediate threading shaft; 12. Circular bearing with seat (for connecting the intermediate threading shaft to the steel strip machine frame); 13. Intermediate shaft brake disc; 14. Second steel strip tension synchronous pulley; 15. Second steel strip servo drive synchronous pulley; 16. First deep groove ball bearing; 17. Shaft elastic retaining ring; 18. First steel strip tension synchronous pulley; 19. First steel strip servo drive synchronous pulley; 20. First steel strip brake disc; 21. First round nut with lubrication oil passage; 22. Wrapping head drive synchronous pulley; 23. Wrapping head brake disc; 24. Bearing seat of the second deep groove ball bearing; 25. Second deep groove ball bearing; 26. Left side fixing disc of the first steel strip; 27. Main guide. 28. Wheel, 29. Right side fixing plate of the first steel belt, 30. Angle wheel support seat, 31. Left side fixing plate of the second steel belt, 32. Right side fixing plate of the second steel belt, 33. Adjusting steel belt angle guide wheel, 34. Adjusting steel belt angle guide wheel fixing plate, 35. Overlap rate adjusting roller, 36. Overlap rate adjusting roller support plate, 37. Threading guide tube, 38. Second steel belt reel shaft end retaining ring, 39. Second round nut with lubricating oil passage, 40. Side roller of wrapping head, 41. Bearing of the first steel belt reel, 42. Grease nipple, 43. First bushing, 44. Second bushing, 45. First steel belt reel shaft, 46. Third bushing, 47. Second ordinary round nut, 48. Torque motor shaft chain, 49. Magnetic powder brake chain, 50. Magnetic powder brake, 51. Torque motor, 52. First servo motor, 53. Second servo motor, 54. Main shaft, 55. First steel belt mounting device, 56. Second steel belt mounting device, 57. Third servo motor, 58. Detailed Implementation

[0039] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0040] This utility model relates to a concentric double-disc steel belt armoring machine (reference). Figure 1 The steel strip machine includes a steel strip machine frame 2, a wrapping head 1 and a steel strip placement device mounted on the steel strip machine frame; the wrapping head and the steel strip placement device have the same axis of rotation.

[0041] With the exit side of the steel strip machine as the front, the front of the wrapping head is the wrapping area. There is a steel strip exit path between the steel strip placement device and the wrapping area. The guide wheel group on the exit path, which is used to support and conduct the steel strip, is installed on the wrapping head.

[0042] Further reference Figure 6 and Figure 7 The steel strip placement device includes a first steel strip placement device 56 and a second steel strip placement device 57, which are located inside the wrapping head of the cage structure.

[0043] The first steel strip placement device and the second steel strip placement device are arranged sequentially from back to front on the same axis, and are located at the rear of the wrapping head;

[0044] Further reference Figure 2 The second steel strip placement device is fixed to the intermediate threading shaft 11, which has a tubular hollow section for cable passage. The first steel strip reel shaft 45 is sleeved on the outside of the intermediate threading shaft via a bearing device, and the first steel strip placement device is fixed to the first steel strip reel shaft. The first steel strip reel shaft is sleeved on the wrapping head connecting shaft (i.e., main shaft 55) via a bearing device. The wrapping head is fixed to the wrapping head connecting shaft. The wrapping head connecting shaft is connected to the steel strip machine frame via a bearing device. The intermediate threading shaft, the first steel strip reel shaft, and the wrapping head connecting shaft are respectively connected to the corresponding drive motors via a transmission mechanism, and all three shafts are connected to a braking device.

[0045] The intermediate threading shaft and the first steel strip reel shaft are also connected to a tension control device (used to control the tension of the first steel strip placement device and the second steel strip placement device).

[0046] See again Figure 1 This also includes a rewinding machine, which is located next to the steel strip machine frame. Further references Figure 3 The tape rewinding machine includes the tape rewinding machine frame 6 and the tape rewinding machine motor mounted on it (i.e., Figure 3 The two steel strip rewinders are a torque motor 52, a first steel strip rewinder 7, and a second steel strip rewinder 8. The rotation axes of the two steel strip rewinders are parallel and parallel to the rotation axis of the wrapping head. The two steel strip rewinders are connected to the rewinding machine motor through a transmission device. The rotating shafts of the first and second steel strip rewinders are also connected to a tension control device.

[0047] The axial positions of the first and second steel strip rewind reels are aligned with the first and second steel strip placement devices of the steel strip machine, respectively; there is an upper belt path between the corresponding steel strip rewind reels and the steel strip placement devices, and steel strip support rollers (i.e., rollers) are installed on the upper belt path. Figure 1 (The upper guide wheel 10 in the middle).

[0048] The steel belt support roller on the upper belt path is connected to the side of the steel belt machine frame 2; the wrapping head side roller 40 is on the upper belt path.

[0049] In the tape rewinding machine, the tape rewinding machine motor is a torque motor; the transmission device between the rotating shafts of the first and second steel tape rewinding reels and the output shaft of the torque motor is a chain drive device. The tension control device in the tape rewinding machine is a magnetic powder brake 51 installed on the tape rewinding machine frame; the magnetic powder brake is connected to the rotating shafts of the first and second steel tape rewinding reels via a chain drive device.

[0050] Multiple lifting plates 5 are connected to the frame of the strip mill; at the far end of the main line of the strip mill, there is a conduit 3, which is connected to the frame 2 of the strip mill through a fixed frame 4 below the conduit.

[0051] The steel strip machine frame is connected to a guard plate, and the wrapping head and steel strip placement device are inside the guard plate; the guard plate has a threading hole, through which the upper path of the steel strip passes.

[0052] Please see Figures 1 to 7 The structure of the concentric double-disc steel belt armoring machine in this embodiment of the project will be described.

[0053] Corresponding to the second steel strip placement device: The core wire / cable, etc., of the steel strip to be wrapped passes through the central hole of the intermediate threading shaft 11 until it exits from the front side of the threading guide tube 37, and the steel strip wrapping begins. The transmission mechanism of the intermediate threading shaft is a synchronous belt drive, the structure of which includes a second steel strip servo drive synchronous pulley 15 and a second steel strip tension synchronous pulley 14. The two synchronous pulleys are connected to the intermediate threading shaft by a key, and axial movement is prevented by the intermediate shaft brake disc 13, the second steel strip tension synchronous pulley 14, and the third bushing 46 and fourth bushing 47 on both sides of the second steel strip servo drive synchronous pulley 15. The intermediate shaft brake disc 13 is connected to the intermediate threading shaft 11, and the braking of the intermediate threading shaft 11 is accomplished by a pneumatic disc brake (brake caliper) clamping the intermediate shaft brake disc 13. The second steel strip tension synchronous pulley 14 is connected to a magnetic powder brake via belt drive. To avoid obscuring parts in the structural diagram, the magnetic powder brake is omitted. Further reference Figure 7 The third servo motor 58 is connected to the second steel belt servo drive synchronous pulley 15.

[0054] Corresponding to the first steel belt mounting device: A first steel belt servo drive synchronous pulley 19 and a first steel belt tension synchronous pulley 18 are connected (possibly by a key) to the first steel belt reel shaft 45. The rotational power of the first steel belt mounting device is transmitted through the first steel belt servo drive synchronous pulley 19, and the servo tension is transmitted through the first steel belt tension synchronous pulley 18. A shaft elastic retaining ring 17 located behind the first steel belt tension synchronous pulley 18 prevents axial movement of the synchronous pulley. The first steel belt brake disc 21 is connected to the first steel belt reel shaft 45, and braking of the first steel belt reel shaft is achieved by clamping the first steel belt brake disc 21 with a pneumatic disc brake (brake caliper). Similarly, the first steel belt tension synchronous pulley 18 is connected to a magnetic powder brake via belt drive; this magnetic powder brake is omitted to avoid obscuring parts in the structural diagram. The first servo motor 53 is connected to the first steel belt servo drive synchronous pulley 19.

[0055] The intermediate threading shaft 11 and the first steel strip reel shaft 45 are connected by a first deep groove ball bearing 16.

[0056] Corresponding to the wrapping head 1: The wrapping head 1 supports the bearing housing 25 of the second deep groove ball bearing 26, and the bearing housing 25 of the second deep groove ball bearing is fixedly connected to the steel strip machine frame 2. The transmission of the wrapping head 1 is achieved by the second servo motor 54 driving the wrapping head drive synchronous pulley 23 to rotate, and the axial movement of the wrapping head drive synchronous pulley 23 is prevented by a common round nut 20.

[0057] The deep groove ball bearings in the connecting shaft (i.e., main shaft 55) can be periodically lubricated through grease fittings 42. For example, lubrication channels are provided on the first round nut 22 with lubrication channels and the second round nut 39 with lubrication channels. This improves the service life of the equipment and reduces the failure rate.

[0058] Support and conduction of the steel strip on the wrapping head: The steel strip in the wrapping head passes sequentially through the main guide wheel 28, the steel strip angle adjustment guide wheel 33 and the overlap rate adjustment guide wheel 35; the overlap angle of the steel strip is adjusted by any one of the following plates: the corner wheel support seat 30, the steel strip angle adjustment guide wheel fixing plate 34 and the overlap rate adjustment roller support plate 36.

[0059] When the steel strip in the winding head is used up, two reels of steel strip are loaded onto the rewinding machine. The first rewinding reel 7 corresponds to the first steel strip placement device in the winding head 1, and the second rewinding reel 8 corresponds to the second steel strip placement device in the winding head 1. After spot welding the steel strip joints of the two reels of steel strip in the rewinding machine and the two reels of steel strip in the winding head to the winding shaft of the corresponding steel strip placement device using a spot welding machine, rewinding can be performed, solving the problem of frequent manual loading and unloading of reels and high labor intensity.

[0060] The tape rewinding machine is driven by a torque motor 52 through a torque motor shaft chain 49, and the tension of the steel tape reel is driven by a magnetic powder brake 51 through a magnetic powder brake chain.

[0061] This utility model relates to a concentric double-disc steel tape armoring machine. During operation, the cable armor layer and the cable core wire form a concentric structure on the same axis. This allows for a more even distribution of pressure on the armor layer, improving the overall performance of the cable. The biggest advantages of this equipment are its high speed and high production capacity.

[0062] The magnetic powder brake in the strip mill regulates the wrapping tension of the strip, enabling tracking from full-reel tension to empty-reel tension. This solves the problem of uneven tension and missed wrapping issues common in traditional strip mills, improving product quality and reliability. It also reduces the risk of missed wrapping quality problems that previously occurred after wrapping, and is significantly faster than traditional wrapping methods, thus increasing production efficiency.

Claims

1. A concentric double-disc steel strip armoring machine, comprising a steel strip machine, the structure of which includes a steel strip machine frame and a wrapping head and a steel strip placement device mounted on the steel strip machine frame; the rotation axes of the wrapping head and the steel strip placement device are the same; With the exit side of the steel strip machine as the front, the front of the wrapping head is the wrapping area. There is a steel strip exit path between the steel strip placement device and the wrapping area. The guide wheel group on the exit path, which is used to support and conduct the steel strip, is installed on the wrapping head. Its characteristics are The steel strip placement device includes a first steel strip placement device and a second steel strip placement device, which are located inside the wrapping head of the cage structure; The first steel strip placement device and the second steel strip placement device are arranged sequentially from back to front on the same axis, and are located at the rear of the wrapping head; The second steel strip placement device is fixed to the intermediate threading shaft, which has a tubular hollow section for cable passage. A first steel strip reel shaft is sleeved on the outside of the intermediate threading shaft via a bearing device, and the first steel strip placement device is fixed to the first steel strip reel shaft. The first steel strip reel shaft is sleeved on the wrapping head connecting shaft via a bearing device. The wrapping head is fixed to the wrapping head connecting shaft. The wrapping head connecting shaft is connected to the steel strip machine frame via a bearing device. The intermediate threading shaft, the first steel strip reel shaft, and the wrapping head connecting shaft are each connected to a corresponding drive motor via a transmission mechanism, and all three are equipped with braking devices. Tension control devices are also connected to the intermediate threading shaft and the first steel strip reel shaft, respectively; It also includes a rewinding machine, which is located next to the steel strip machine frame; The tape rewinding machine includes a tape rewinding machine frame and a tape rewinding machine motor and first and second steel tape rewinding reels mounted on it; the rotation axes of the two steel tape rewinding reels are parallel and parallel to the rotation axis of the wrapping head; the two steel tape rewinding reels are connected to the tape rewinding machine motor through a transmission device; the rotation shafts of the first and second steel tape rewinding reels are also connected to a tension control device; The axial positions of the first and second steel strip rewinding discs are aligned with the first and second steel strip placement devices of the steel strip machine, respectively; there is an upper belt path between the corresponding steel strip rewinding discs and steel strip placement devices, and steel strip support rollers are installed on the upper belt path.

2. The concentric double-disc steel belt armoring machine according to claim 1, characterized in that: The steel belt support rollers on the upper belt path are connected to the side of the steel belt machine frame; the wrapping head side rollers are on the upper belt path.

3. The concentric double-disc steel belt armoring machine according to claim 1, characterized in that: In the tape rewinding machine, the tape rewinding machine motor is a torque motor; the transmission device between the rotating shaft of the first and second steel tape rewinding discs and the output shaft of the torque motor is a chain drive device.

4. The concentric double-disc steel belt armoring machine according to claim 3, characterized in that: The tension control device in the tape rewinding machine is a magnetic powder brake installed on the tape rewinding machine frame; the magnetic powder brake is connected to the rotating shaft of the first and second steel tape rewinding discs via a chain drive.

5. The concentric double-disc steel belt armoring machine according to claim 1, characterized in that: The tension control device in the steel strip machine is a magnetic powder brake; the intermediate threading shaft and the first steel strip reel shaft are each connected to a magnetic powder brake through a transmission mechanism.

6. The concentric double-disc steel belt armoring machine according to claim 1, characterized in that the steel belt... Multiple lifting plates are connected to the machine frame; at the far end of the main line of the steel strip machine, there is a conduit, which is connected to the steel strip machine frame through the fixed frame below the conduit.

7. The concentric double-disc steel belt armoring machine according to claim 1, characterized in that the steel belt... The machine frame is connected to a guard plate, and the wrapping head and steel strip placement device are inside the guard plate; the guard plate has a strip-passing hole, through which the upper path of the steel strip passes.

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