Automatic stretching device for gold steel wire rope rigging
By designing the automatic stretching device of gold wire rope rig, the problems of poor stability and low accuracy of traditional testing methods are solved, and automatic stretching and clamping are achieved, which improves the stability and accuracy of the test.
Patent Information
- Application Number
- CN202510726282.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-06-03
- Publication Date
- 2025-08-08
- Estimated Expiration
- Not applicable · inactive patent
AI Technical Summary
The traditional tensile testing method for wire ropes has problems such as poor stability, large error and low accuracy, and manual determination of tension value is inaccurate.
An automatic stretching device for gold wire rope rigs is designed, including a twister, a rolling table, an adjustment device, a moving device and a gripping device. Through the combination of pulleys, swing rods, cylinders and gripping blocks, it can achieve automatic stretching and clamping to adapt to different specifications of wire rope rigs.
Automatic tensile testing of wire rope rigs is realized, which improves the stability and accuracy of the test, reduces human errors, and ensures the reliability of the test results.
Smart Images
Figure CN120443491A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of gold wire rope slings, in particular to an automatic stretching device for a gold wire rope sling. Background Art
[0002] In today's industrial field, steel wire rope slings have been widely used in industries such as steel, chemical industry, transportation, and ports due to their many advantages, such as high strength, light weight, stable operation, and resistance to sudden breakage. However, in actual use, the performance of steel wire rope slings faces many challenges. For example, when steel wire rope slings need to be tensile tested, traditional testing methods have exposed many drawbacks. The traditional method is often to manually fix one end of the hardware sling and stretch the other end with a tensioner. Then, after applying a certain amount of tension, the hardware sling is manually observed to see whether it breaks or is severely deformed, thereby judging whether it is qualified. However, this method of manually applying tension and manually determining the tension value has problems such as poor stability, large errors, and short action time, which seriously affect the accuracy and reliability of the test results. Based on this, the present invention proposes an automatic tensioning device for steel wire rope slings to solve the above problems. Summary of the Invention
[0003] The object of the present invention is to provide an automatic stretching device for a gold wire rope sling to solve the problems raised in the above background technology.
[0004] To achieve the above-mentioned object, the present invention provides the following technical solution: an automatic stretching device for a gold wire rope sling, comprising a stranding machine, wherein the outlet of the stranding machine is correspondingly connected to a rolling platform, wherein the rolling platform is used to roll and transmit the gold wire rope strands output by the stranding machine to the next workstation, and the tail end of the rolling platform is correspondingly connected to a stretching device, wherein the stretching device includes an adjusting device, a movable device and a gripping device, wherein the adjusting device is used to manually adjust the overall height of the device to adapt to the transmission height of gold wire rope slings of different specifications; The movable device is used to drive the correspondingly connected grasping device on the top to move horizontally left and right, grab the transmitted gold wire rope sling and stretch it to meet subsequent use requirements.
[0005] As a preferred technical solution of the present invention, the adjusting device includes four pulleys, both sides of the four pulleys are movably connected to the first base plate, both ends of the top of the first base plate are fixedly connected to the swing device, both sides of the two swing devices are movably connected to the first swing rod, and the inner sides of the four first swing rods are movably connected to two second swing rods.
[0006] As a preferred technical solution of the present invention, the bottoms of the two second swing arms are movably connected to the first rotating shaft, and both ends of the two first rotating shafts are movably connected to the raised parts of the top of the first bottom plate, and the outer sides of the tops of the four first swing arms are movably connected to support plates, and the tops of the support plates are fixedly connected to a movable device.
[0007] As a preferred technical solution of the present invention, the swinging device includes a hollow plate, a second rotating shaft is movably connected to the hollow part of the bottom of the hollow plate, and the two ends of the second rotating shaft are movably connected to the bottom of the two first swing rods, the top outer surface of the second rotating shaft is movably connected to a connecting plate, the top center of the connecting plate is movably connected to a threaded rod, and the top of the threaded rod is movably connected to a rotating disk.
[0008] As a preferred technical solution of the present invention, the movable device includes a second base plate, the bottom of the second base plate is fixedly connected to the top of the support plate, the top center of the second base plate is fixedly connected to a third rotating shaft, the top of the third rotating shaft is movably connected to a gear, both sides of the outer surface of the gear are meshed with racks, and the bottom ends of the two racks are fixedly connected to one end of the sliding block.
[0009] As a preferred technical solution of the present invention, the bottom of the two sliding blocks are movably connected to a sliding rod, and the bottom of the two sliding rods are fixedly connected to the two ends of the top of the second base plate, the other ends of the top of the two sliding blocks are fixedly connected to a placement block, the top of the two placement blocks are fixedly connected to a gripping device, and the rear end of one of the placement blocks is correspondingly connected to a cylinder.
[0010] As a preferred technical solution of the present invention, the grasping device includes a fixed block, the bottom of the fixed block is fixedly connected to the top of the placement block, a telescopic rod is fixedly connected to the hollow part of the bottom of the fixed block, a disc is fixedly connected to the top of the telescopic rod, and four pushing columns are fixedly connected to the top of the disc.
[0011] As a preferred technical solution of the present invention, the four pushing columns are movably connected to elliptical plates on both sides, the four elliptical plates are movably connected to clamping blocks at the top grooves, the four clamping blocks are movably connected to the fourth rotating shaft at the bending parts, the four fourth rotating shafts are movably connected to movable blocks at both ends, and the bottoms of the four movable blocks are fixedly connected to the top of the fixed block.
[0012] Compared with the prior art, the present invention has the following beneficial effects: (1) An automatic stretching device for a gold wire rope sling, which is convenient for moving the entire device by arranging four pulleys at the bottom of a first base plate, and can be pushed to the side of a gold wire rope sling at different heights. When the swing devices at both ends of the top of the first base plate slide toward or away from each other, they will pull the first swing rods movably connected on both sides to move. Since the top of the second swing rod is movably connected to the inner side of the center of the first swing rod and the bottom is movably connected to the first base plate, when the first swing rod moves, it will be raised or lowered with the support of the second swing rod.
[0013] (2) An automatic stretching device for a gold wire rope sling, which is provided with a second rotating shaft at the hollow part of the bottom of the hollow plate. When the rotating disk is manually rotated, the threaded rod fixedly connected to its rear end will be driven to rotate synchronously. Since the threaded rod is connected to the threaded hole at the top of the connecting plate, the rotation of the threaded rod can make the connecting plate move in a straight line in the horizontal direction, thereby pulling the second rotating shaft at the bottom of the connecting plate to slide in the hollow area of the hollow plate, and then driving the bottom of the first swinging rod connected to both ends of the second rotating shaft to move, and accurately adjusting the opening angle of the first swinging rod to the appropriate position.
[0014] (3) An automatic stretching device for a wire rope, which is provided with a placement block at the output shaft end of the cylinder. When the cylinder drives the placement block to move forward, the sliding block fixedly connected to the bottom of the placement block will slide along the outer surface of the sliding rod, which not only provides stable support for the placement block and the gripping device connected to the top, but also reduces the sliding friction resistance. At this time, the movement of the sliding block will quickly push the rack fixedly connected to the other end to slide synchronously. Since one of the racks is engaged with the inner gear, it will drive the rotation of the gear, and the other rack on the other side of the outer surface of the gear will perform synchronous movement at the same speed and in the opposite direction.
[0015] (4) An automatic stretching device for a gold wire rope, which is provided with a disc on the top of a telescopic rod. When the telescopic rod is extended and retracted up and down under the drive of external electricity, it will drive the disc fixed on the top to move synchronously. The top of each disc is fixedly connected to four push columns, so the push columns will move in the same direction as the disc. When the push columns move downward, the elliptical plate connected to the top will be pulled by tension to quickly pull the bottom end of the movable clamping block on the top to move synchronously. Since the clamping block is a V-shaped structure, when the bottom end is pulled downward, the curved part of the clamping block will rotate around the outer surface of the fourth rotating shaft, so that the top ends of the four clamping blocks can be retracted toward the center, and finally the gold wire rope is clamped. BRIEF DESCRIPTION OF THE DRAWINGS
[0016] Figure 1 It is a side structural schematic diagram of the present invention; Figure 2 It is an overall schematic diagram of the stretching device in the present invention; Figure 3Schematic diagram of the regulating device in the present invention; Figure 4 Schematic diagram of the connection between the swing device and the first swing rod in the present invention; Figure 5 Schematic diagram of the movable device in the present invention; Figure 6 Schematic diagram of the connection between the rack and the sliding block in the present invention; Figure 7 Schematic diagram of the gripping device in the present invention; Figure 8 Schematic diagram of the connection between the push column and the elliptical plate in the present invention.
[0017] In the figure: 1. stranding machine; 2. rolling table; 3. stretching device; 31. adjusting device; 311. pulley; 312. first bottom plate; 313. swinging device; 314. first swinging rod; 315. second swinging rod; 316. first rotating shaft; 317. supporting plate; 32. movable device; 321. second bottom plate; 322. third rotating shaft; 323. gear; 324. rack; 325. sliding block; 326. Sliding rod; 327. Placing block; 328. Cylinder; 33. Clamping device; 331. Fixed block; 332. Telescopic rod; 333. Disc; 334. Push column; 335. Oval plate; 336. Clamping block; 337. Fourth rotating axis; 338. Movable block; 3131. Hollow plate; 3132. Second rotating axis; 3133. Connecting plate; 3134. Threaded rod; 3135. Rotating disk. DETAILED DESCRIPTION
[0018] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.
[0019] Example 1: Please refer to Figure 1-Figure 2 An automatic stretching device for a gold wire rope sling includes a stranding machine 1. The outlet of the stranding machine 1 is correspondingly connected to a rolling platform 2. The rolling platform 2 is used to roll the gold wire rope strands output by the stranding machine 1 to the next workstation. The tail end of the rolling platform 2 is correspondingly connected to a stretching device 3. The stretching device 3 includes an adjusting device 31, a movable device 32 and a gripping device 33. The adjusting device 31 is used to manually adjust the overall height of the device to adapt to the transmission height of gold wire rope slings of different specifications. The movable device 32 is used to drive the correspondingly connected grasping device 33 on the top to move horizontally left and right, grab the transmitted gold wire rope sling and stretch it to meet subsequent use requirements.
[0020] Example 2: Based on Example 1, Figure 3-8 As shown, the adjusting device 31 includes four pulleys 311, and a first base plate 312 is provided on both sides of the four pulleys 311, and both sides of the four pulleys 311 are movably connected to the raised parts at the bottom of the first base plate 312, and both ends of the top of the first base plate 312 are fixedly connected to the bottom of the swing device 313, and a first swing rod 314 is provided on both sides of the two swing devices 313, and both sides of the two swing devices 313 are movably connected to the bottom of the first swing rod 314, two second swing rods 315 are provided on the inner side of the four first swing rods 314, and the inner sides of the four first swing rods 314 are movably connected to the outer sides of the two second swing rods 315.
[0021] The bottom of each of the two second swinging rods 315 is provided with a first rotating shaft 316, and the bottom of each of the two second swinging rods 315 is movably connected to the outer surface of the first rotating shaft 316, and both ends of the two first rotating shafts 316 are movably connected to the top protrusion of the first bottom plate 312, and the top outer side of the four first swinging rods 314 is provided with a support plate 317, and the top outer side of the four first swinging rods 314 is movably connected to the bottom of the support plate 317. By arranging the four pulleys 311 at the bottom of the first bottom plate 312, it is possible to The entire device moves and is pushed to the side of the gold wire rope rigging at different heights. When the swing devices 313 at both ends of the top of the first base plate 312 slide toward or away from each other, they pull the first swing rod 314, which is movably connected on both sides, to move. Because the top of the second swing rod 315 is movably connected to the center inner side of the first swing rod 314 and the bottom is movably connected to the first base plate 312, when the first swing rod 314 moves, it is supported by the second swing rod 315 to be raised or lowered, thereby adjusting to the appropriate working height. The movable device 32 is provided on the top of the support plate 317, and the top of the support plate 317 is fixedly connected to the bottom of the movable device 32.
[0022] The swing device 313 includes a hollow plate 3131, a second rotating shaft 3132 is provided at the hollow bottom of the hollow plate 3131, and the hollow bottom of the hollow plate 3131 is movably connected to the outer surface of the second rotating shaft 3132, and the two ends of the second rotating shaft 3132 are movably connected to the bottom of the two first swing rods 314, a connecting plate 3133 is provided on the top outer surface of the second rotating shaft 3132, and the top outer surface of the second rotating shaft 3132 is movably connected to the bottom of the connecting plate 3133, a threaded rod 3134 is provided at the top center of the connecting plate 3133, and the top center of the connecting plate 3133 is movably connected to the outer surface of the threaded rod 3134, and the top of the threaded rod 3134 is provided The rotating disk 3135 is provided with a second rotating shaft 3132 in the hollowed-out portion at the bottom of the hollowed-out plate 3131. When the rotating disk 3135 is manually rotated, it drives the threaded rod 3134, which is fixedly connected to its rear end, to rotate synchronously. Because the threaded rod 3134 is connected to the threaded hole at the top of the connecting plate 3133, the rotation of the threaded rod 3134 causes the connecting plate 3133 to move in a straight line in the horizontal direction, thereby pulling the second rotating shaft 3132 at the bottom of the connecting plate 3133 to slide within the hollowed-out portion of the hollowed-out plate 3131. This subsequently drives the bottom of the first swinging rod 314, which is connected to both ends of the second rotating shaft 3132, to move, precisely adjusting the opening angle of the first swinging rod 314 to the desired position. The top end of the threaded rod 3134 is movably connected to the rear end of the rotating disk 3135.
[0023] The movable device 32 includes a second base plate 321, the bottom of the second base plate 321 is fixedly connected to the top of the support plate 317, a third rotating shaft 322 is provided at the top center of the second base plate 321, and the top center of the second base plate 321 is fixedly connected to the bottom of the third rotating shaft 322, a gear 323 is provided at the top of the third rotating shaft 322, and the top of the third rotating shaft 322 is movably connected to the inside of the gear 323, racks 324 are provided on both sides of the outer surface of the gear 323, and both sides of the outer surface of the gear 323 are meshed with the inner side of the rack 324, one end of the sliding block 325 is provided at the bottom end of the two racks 324, and the bottom ends of the two racks 324 are fixedly connected to the top end of the sliding block 325.
[0024] The bottom of the two sliding blocks 325 are both provided with sliding rods 326, and the bottoms of the two sliding blocks 325 are movably connected to the outer surfaces of the sliding rods 326, and the bottoms of the two sliding rods 326 are fixedly connected to the two ends of the top of the second bottom plate 321, and the other ends of the tops of the two sliding blocks 325 are both provided with placement blocks 327, and the other ends of the tops of the two sliding blocks 325 are fixedly connected to the bottoms of the placement blocks 327, and the tops of the two placement blocks 327 are provided with gripping devices 33. By arranging the placement block 327 at the output shaft end of the cylinder 328, when the cylinder 328 drives the placement block 327 to move forward, the placement The sliding block 325 fixedly connected to the bottom of the block 327 slides along the outer surface of the sliding rod 326. This not only provides stable support for the placement block 327 and the gripping device 33 connected to its top, but also reduces sliding friction. At this time, the movement of the sliding block 325 quickly pushes the rack 324 fixedly connected at the other end to slide synchronously. Since one rack 324 meshes with the inner gear 323, it drives the gear 323 to rotate. The other rack 324 on the other side of the outer surface of the gear 323 will also move synchronously at the same speed and in the opposite direction, achieving the tensioning or loosening operation of the gold wire rope. The tops of the two placement blocks 327 are fixedly connected to the bottom of the gripping device 33, and the rear end of one of the placement blocks 327 is correspondingly connected to the cylinder 328.
[0025] The grasping device 33 includes a fixed block 331, the bottom of which is fixedly connected to the top of the placement block 327, a telescopic rod 332 is provided at the hollowed-out bottom of the fixed block 331, and the hollowed-out bottom of the fixed block 331 is fixedly connected to the bottom of the telescopic rod 332, a disc 333 is provided at the top of the telescopic rod 332, and the top of the telescopic rod 332 is fixedly connected to the bottom center of the disc 333, four pushing columns 334 are provided at the top of the disc 333, and the top of the disc 333 is fixedly connected to the bottom of the four pushing columns 334.
[0026] The four pushing posts 334 are each provided with an elliptical plate 335 on both sides, and both sides of the four pushing posts 334 are movably connected to the bottom of the elliptical plate 335, the four top grooves of the elliptical plates 335 are each provided with a clamping block 336, and the four top grooves of the elliptical plates 335 are movably connected to the bottom of the clamping block 336, the four clamping blocks 336 are each provided with a fourth rotating shaft 337 at the bend, and the four clamping blocks 336 are each movably connected to the center of the fourth rotating shaft 337, and the four fourth rotating shafts 337 are each provided with a movable block 338 at both ends. By arranging a disc 333 on the top of the telescopic rod 332, when the telescopic rod 332 When the lever 333 is extended and retracted upward and downward under external power, it drives the synchronous movement of the disc 333 fixed at its top. Four push rods 334 are fixedly connected to the top of each disc 333, so the push rods 334 move in the same direction as the disc 333. As the push rods 334 move downward, the elliptical plate 335 connected to its top is pulled by tension, rapidly pulling the bottom end of the movably connected clamping block 336 at the top to move synchronously. Because the clamping block 336 has a V-shaped structure, when the bottom end is pulled downward, the curved portion of the clamping block 336 rotates around the outer surface of the fourth rotation axis 337, causing the top ends of the four clamping blocks 336 to converge toward the center, ultimately achieving an encircling clamping of the gold wire rope. The four fourth rotation axes 337 are each movably connected to the top of a movable block 338 at both ends, and the bottoms of the four movable blocks 338 are fixedly connected to the top of the fixed block 331.
[0027] The working principle of the present invention is as follows: Strand transmission: After the stranding machine 1 twists the steel wire into strands, the rolling structure of the rolling table 2 transmits the strands to the front of the stretching device 3. The continuous rolling realizes the stable transmission of the strands from the twisting station to the stretching station. Height adjustment: The adjusting device 31 needs to be manually operated to achieve overall height adjustment. When the rotating disk 3135 is manually rotated, the threaded rod 3134 fixedly connected to the rear end of the rotating disk 3135 will be driven to rotate synchronously, so that the connecting plate 3133 connected to the outer surface of the threaded rod 3134 can only move in the horizontal direction, and pull the second rotating shaft 3132 to slide in the hollow area of the hollow plate 3131, and then drive the movement of the bottom of the first swinging rod 314. Because the inner side of the first swinging rod 314 is movably connected to the outer side of the second swinging rod 315, the bottom of the second swinging rod 315 is movably connected to the first bottom plate 312 through the first rotating shaft 316. When the first swinging rod 314 moves, the support plate 317 can be raised or lowered with the support of the second swinging rod 315 to adapt to different conveying heights. The four pulleys 311 at the bottom facilitate the overall movement of the stretching device 3 to different positions to match the conveying heights of strands of wire of different specifications. Clamping and fixing: In the movable device 32, the cylinder 328 drives the placement block 327 fixedly connected to the output shaft to move forward. The movement of the placement block 327 drives the sliding block 325 connected at the bottom to slide along the outer surface of the sliding rod 326, reducing the sliding friction resistance. At the same time, the movement of the sliding block 325 quickly pushes the rack 324 fixedly connected to the other end of the top to slide synchronously. The rack 324 is engaged with the gear 323 to drive the rotation of the gear 323, allowing the rack 324 on the other side to move in the opposite direction at the same speed. Finally, the two placement blocks 327 drive the grasping device 33 to move horizontally toward or away from each other to tighten or loosen the wire rope sling; Synchronous stretching: When the gripping device 33 is working, the telescopic rod 332 will stretch up and down under the power drive, and the circular disc 333 and the four push columns 334 connected to the top will move synchronously. When the push column 334 moves downward, the elliptical plate 335 connected to the top will be pulled by the tension to quickly pull the bottom end of the movable clamping block 336 at the top to move synchronously. Since the clamping block 336 has a V-shaped structure, when the bottom end is pulled downward, the curved part of the clamping block 336 will rotate around the outer surface of the fourth rotating shaft 337, so that the top ends of the four clamping blocks 336 will be retracted toward the center, encircling and clamping the gold wire rope sling, and otherwise loosening it. Reset cycle: After the stretching is completed, the cylinder 328 drives the device to reset, the clamping block 336 releases the strands, the rolling table 2 continues to transport the next group of strands, and the device enters the next round of stretching operation to achieve automated continuous production.
[0028] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.
Claims
1. An automatic stretching device for a gold wire rope, comprising a stranding machine (1), characterized in that: The outlet of the stranding machine (1) is connected to a rolling platform (2) for rolling the gold wire rope strands outputted from the stranding machine (1) to the next workstation. The tail end of the rolling platform (2) is connected to a stretching device (3) for manually adjusting the overall height of the device to adapt to the conveying height of gold wire rope slings of different specifications. The movable device (32) is used to drive the correspondingly connected grasping device (33) on the top to move horizontally left and right, grasp the transmitted gold wire rope sling and stretch it to meet subsequent use requirements.
2. The automatic stretching device for a gold wire rope according to claim 1, characterized in that: The adjusting device (31) comprises four pulleys (311), both sides of the four pulleys (311) are movably connected to a first base plate (312), both ends of the top of the first base plate (312) are fixedly connected to a swing device (313), both sides of the two swing devices (313) are movably connected to a first swing rod (314), and the inner sides of the four first swing rods (314) are movably connected to two second swing rods (315).
3. The automatic stretching device for a gold wire rope according to claim 2, characterized in that: The bottoms of the two second swinging rods (315) are movably connected to the first rotating shaft (316), and both ends of the two first rotating shafts (316) are movably connected to the raised portion of the top of the first bottom plate (312). The outer sides of the tops of the four first swinging rods (314) are movably connected to the support plates (317), and the tops of the support plates (317) are fixedly connected to the movable device (32).
4. The automatic stretching device for a gold wire rope according to claim 2, characterized in that: The swing device (313) comprises a hollow plate (3131), wherein a second rotating shaft (3132) is movably connected to a hollow portion of the bottom of the hollow plate (3131), and both ends of the second rotating shaft (3132) are movably connected to the bottoms of the two first swing rods (314). A connecting plate (3133) is movably connected to the outer surface of the top of the second rotating shaft (3132), a threaded rod (3134) is movably connected to the center of the top of the connecting plate (3133), and a rotating disk (3135) is movably connected to the top of the threaded rod (3134).
5. The automatic stretching device for a gold wire rope according to claim 3, characterized in that: The movable device (32) includes a second base plate (321), the bottom of the second base plate (321) is fixedly connected to the top of the support plate (317), the top center of the second base plate (321) is fixedly connected to a third rotating shaft (322), the top of the third rotating shaft (322) is movably connected to a gear (323), both sides of the outer surface of the gear (323) are meshed with racks (324), and the bottom ends of the two racks (324) are fixedly connected to one end of a sliding block (325).
6. The automatic stretching device for a gold wire rope according to claim 5, characterized in that: The bottoms of the two sliding blocks (325) are movably connected to sliding rods (326), and the bottoms of the two sliding rods (326) are fixedly connected to the two ends of the top of the second bottom plate (321). The other ends of the tops of the two sliding blocks (325) are fixedly connected to placement blocks (327), and the tops of the two placement blocks (327) are fixedly connected to gripping devices (33), and the rear end of one of the placement blocks (327) is correspondingly connected to a cylinder (328).
7. The automatic stretching device for a gold wire rope according to claim 6, characterized in that: The gripping device (33) comprises a fixed block (331), the bottom of the fixed block (331) is fixedly connected to the top of the placement block (327), a telescopic rod (332) is fixedly connected to the hollow portion of the bottom of the fixed block (331), a disc (333) is fixedly connected to the top of the telescopic rod (332), and four push columns (334) are fixedly connected to the top of the disc (333).
8. The automatic stretching device for a gold wire rope according to claim 7, characterized in that: Both sides of the four pushing columns (334) are movably connected to elliptical plates (335), the top grooves of the four elliptical plates (335) are movably connected to clamping blocks (336), the bending parts of the four clamping blocks (336) are movably connected to fourth rotating shafts (337), both ends of the four fourth rotating shafts (337) are movably connected to movable blocks (338), and the bottoms of the four movable blocks (338) are fixedly connected to the top of the fixed block (331).