Door ring assembly for plastic circular loom and plastic circular loom

Abstract

The present invention discloses a gate ring assembly for a plastic circular loom, which belongs to the field of plastic weaving machinery and solves the problem that the bearings of the gate ring assembly in the prior art are easily damaged and difficult to replace. The technical solution to this problem is mainly that the upper end of the rotating shaft is connected to the upper gate ring through an upper bearing, and the lower end of the rotating shaft is connected to the lower gate ring through a lower bearing. The upper gate ring is provided with an upper through hole for convenient installation of the rotating shaft, and the outer ring of the upper bearing is fixedly matched with the upper through hole. The lower gate ring is provided with a lower through hole for convenient installation of the rotating shaft, and the outer ring of the lower bearing is fixedly matched with the lower through hole. The present invention is mainly used to increase the width of the wire feeding channel and improve the service life of the bearing. In addition, the present invention also provides a plastic circular loom, which adopts the above-mentioned gate ring assembly for a plastic circular loom to reduce the use cost of the machine and ensure production efficiency.

Description

Technical Field

[0001] The invention relates to a plastic weaving machine, in particular to a door ring assembly for a plastic circular loom and a plastic circular loom using the door ring assembly for a plastic circular loom. Background Art

[0002] In order to improve the production efficiency of woven bags, it is generally considered to increase the speed of the shuttle. Therefore, a suspended plastic circular loom has appeared on the market. The roller or wheel between the upper and lower door rings forms a rolling track for the shuttle to run. When the shuttle is running, it is suspended between the upper and lower door rings due to the centrifugal force. Because it does not contact the upper and lower door rings, the friction resistance of the shuttle is small, and the running speed can be increased. However, as the shuttle speed increases, the centrifugal force it generates will increase and act completely on the roller or wheel, and the roller or wheel is installed on the shaft through the bearing. The shuttle impacts the roller or wheel, causing the roller or wheel to rotate, making the bearing load relatively large, resulting in a decrease in the service life of the bearing. Once the bearing is damaged, it needs to be stopped for replacement. The longer it takes to replace the bearing, the greater the impact on the company's production efficiency.

[0003] In order to improve the service life of bearings, there are generally two ways. One is to increase the number of bearings, that is, to set multiple bearings in parallel on the rotating shaft, and the load is evenly distributed. Since the bearing is a vulnerable part relative to the entire plastic circular loom, this method is very inconvenient to assemble and disassemble, which is not conducive to the long-term use of woven bag manufacturers. The other is to increase the size of the bearing and use a larger type of bearing. Since a wire feeding channel for the warp wire to pass through is formed between two adjacent rollers, on the common four-shuttle or six-shuttle plastic circular looms, the size of the upper and lower door rings is basically fixed, so the center distance between the two adjacent rotating shafts is fixed. If the outer diameter of the bearing becomes larger, the outer diameter of the roller or roller will become larger, the spacing between the rollers or rollers on the adjacent rotating shafts will become smaller, and the width of the wire feeding channel will become smaller. During the weaving process, it is easy to cause the plastic wire to be entangled by the roller or roller, causing the plastic wire to break, affecting the weaving efficiency and quality. Therefore, the roller diameter cannot be too large, that is, it is difficult to choose a larger size for the bearing in a limited space.

[0004] In the prior art, the impact force of the shuttle on the roller or wheel on the same shaft is first shared by multiple bearings and then transferred to the shaft. Since the shuttle runs very fast, it cannot be guaranteed that the impact force acting on each roller or wheel is uniform, so the impact force borne by each bearing is not necessarily the same, which leads to different degrees of wear of multiple bearings on the same shaft, resulting in the rolling track being unable to maintain a vertical state and being partially tilted, resulting in radial runout of the shuttle during operation, which may cause increased noise at the least and broken wire and flying shuttle at the worst. When the bearing needs to be replaced, the shaft must be disassembled together with the roller or wheel before the damaged bearing can be removed. In particular, since different bearings have different degrees of wear, if a new bearing is replaced and installed on the same shaft together with an undamaged old bearing, the rolling track will still be tilted due to the different degrees of wear of the new and old bearings.

[0005] In addition, since the bearings are concentratedly installed in the small space between the upper door ring and the lower door ring, and the outer periphery of the roller or roller is wrapped with colloid, the heat generated by the high-speed rotation of the bearing is difficult to dissipate in time, which will aggravate the damage to the bearing. Summary of the invention

[0006] The object to be achieved by the present invention is to provide a door ring assembly for a plastic circular loom, which increases the width of a wire feeding channel and improves the service life of a bearing.

[0007] In order to achieve the above-mentioned purpose, the present invention adopts the following technical scheme: a door ring assembly for a plastic circular loom, comprising an upper door ring and a lower door ring, a plurality of rotating shafts are arranged between the upper door ring and the lower door ring, all the rotating shafts are arranged in a ring to form a rolling track for the shuttle to run, and a wire feeding channel for the warp to pass through is formed between two adjacent rotating shafts, the upper end of the rotating shaft is connected to the upper door ring through an upper bearing, and the lower end of the rotating shaft is connected to the lower door ring through a lower bearing, the upper door ring is provided with an upper through hole for convenient installation of the rotating shaft, the outer ring of the upper bearing is fixedly matched with the upper through hole, and the lower door ring is provided with a lower through hole for convenient installation of the rotating shaft, and the outer ring of the lower bearing is fixedly matched with the lower through hole.

[0008] Furthermore, the upper door ring is provided with a first upper positioning member for axially positioning the upper end of the upper bearing outer ring, and the lower door ring is provided with a first lower positioning member for axially positioning the lower end of the lower bearing outer ring.

[0009] Furthermore, the first upper positioning member includes an upper pressure cover covering the upper bearing, and the first lower positioning member includes a lower pressure cover covering the lower bearing.

[0010] Furthermore, the upper end of the rotating shaft is provided with an upper shoulder or a second upper positioning member for axially positioning the lower end of the upper bearing inner ring, and the lower end of the rotating shaft is provided with a lower shoulder or a second lower positioning member for axially positioning the upper end of the lower bearing inner ring.

[0011] Furthermore, a third upper positioning member for axially positioning the upper end of the upper bearing inner ring is provided at the upper end of the rotating shaft, and a third lower positioning member for axially positioning the lower end of the lower bearing inner ring is provided at the lower end of the rotating shaft.

[0012] Furthermore, an upper dust cover is provided at the lower end of the upper through hole, and a lower dust cover is provided at the upper end of the lower through hole.

[0013] Furthermore, a rubber sleeve is provided on the outer periphery of the rotating shaft to mitigate the impact of the shuttle.

[0014] Furthermore, the upper door ring and the lower door ring are kept at a fixed distance after being axially positioned by the rotating shaft; or, a support rod is provided between the upper door ring and the lower door ring to keep the fixed distance between them.

[0015] In addition, the present invention also provides a plastic circular loom, including a frame, a main motor, a shuttle and a door ring assembly. The door ring assembly is the door ring assembly for the plastic circular loom mentioned above. The main motor drives the shuttle to perform circular motion on a rolling track formed by a rotating shaft.

[0016] After adopting the above technical solution, the present invention has the following advantages:

[0017] First, the upper bearing and the lower bearing are removed from between the upper and lower gate rings. The width of the wire feeding channel is only affected by the diameter of the shaft. Under the condition of ensuring the strength of the shaft, the space saved by removing the bearings can be used to increase the width of the wire feeding channel. The warp wire is less likely to contact and wear the shaft when passing through the wire feeding channel, thereby reducing the possibility of warp wire breakage.

[0018] Second, the upper bearing and the lower bearing are used to connect the rotating shaft with the upper door ring and the lower door ring, which reduces the number of parts in terms of production and assembly, makes production and assembly easier, and can reduce production costs;

[0019] Third, the upper bearing and the lower bearing are moved out from between the upper door ring and the lower door ring, so that the selection of bearing models is not restricted by the limited space between the upper door ring and the lower door ring, and bearings with longer service life can be selected according to actual needs;

[0020] Fourth, since there is no bearing between the upper and lower gate rings, the part of the shaft between the upper and lower gate rings can be made into a smooth shaft section, so that the warp will not be blocked by the shaft and accidentally broken during the process of the warp opening and closing;

[0021] Fifth, the upper bearing and the lower bearing are located outside the wire feeding channel, and the heat generated by the rotation of the upper bearing and the lower bearing is easy to dissipate, which is also beneficial to increase the service life of the upper bearing and the lower bearing;

[0022] Sixth, since dust is generated by friction and wear between the yarn inlet channel and the upper and lower gate rings during the warp conveying process, after the upper and lower bearings are moved out of the yarn inlet channel, the possibility of dust accumulation on the upper and lower bearings can be reduced;

[0023] Seventh, since the upper bearing and the lower bearing are installed at the upper and lower ends of the rotating shaft, only the shaft heads at both ends of the rotating shaft need to be fine-machined, and the part between the upper bearing and the lower bearing only needs to meet the conventional requirements, which can reduce the machining accuracy of the rotating shaft and reduce the machining cost of the rotating shaft;

[0024] Eighth, the upper bearing and the lower bearing are located outside the wire feeding channel, and a single bearing can be replaced. Even on the same shaft, the upper bearing can be replaced without disassembling the shaft and the lower bearing, and vice versa, it is more convenient to replace the upper bearing and the lower bearing;

[0025] Ninth, the impact of the shuttle on the rotating shaft is a one-to-one action and reaction force, and then the rotating shaft transmits the impact force to the upper bearing and the lower bearing. Therefore, it is easier for the rotating shaft to transfer the impact force of the shuttle to the upper bearing and the lower bearing evenly, so that the wear conditions and service life of the upper bearing and the lower bearing are similar, which can ensure that the rotating shaft is in a vertical state for a long time and reduce the possibility of large radial jumps of the shuttle. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The present invention will be further described below in conjunction with the accompanying drawings:

[0027] Figure 1 is a schematic diagram of Embodiment 1 of the present invention;

[0028] Figure 2 A partial cross-sectional view of the first embodiment of the present invention;

[0029] Figure 3 It is a partial cross-sectional view of the second embodiment of the present invention. DETAILED DESCRIPTION

[0030] Embodiment 1:

[0031] The present invention provides a door ring assembly for a plastic circular loom, Figure 1 and Figure 2As shown, it includes an upper door ring 1 and a lower door ring 2, and a plurality of rotating shafts 3 are arranged between the upper door ring 1 and the lower door ring 2. All the rotating shafts 3 are arranged in a ring to form a rolling track for the shuttle 9 to run, and a wire feeding channel 300 for the warp wire to pass through is formed between two adjacent rotating shafts 3. The upper end of the rotating shaft 3 is connected to the upper door ring 1 through an upper bearing 41, and the lower end of the rotating shaft 3 is connected to the lower door ring 2 through a lower bearing 42. The upper bearing 41 is not lower than the lower surface of the upper door ring 1 and the lower bearing 42 is not higher than the upper surface of the lower door ring 2, so that the width of the wire feeding channel 300 between the two adjacent rotating shafts 3 is increased, the upper door ring 1 is provided with an upper through hole 100 for convenient installation of the rotating shaft 3, and the lower door ring 2 is provided with a lower through hole 200 for convenient installation of the rotating shaft 3.

[0032] First, the upper bearing 41 and the lower bearing 42 are removed from between the upper door ring 1 and the lower door ring 2. The width of the wire feeding channel 300 is only affected by the diameter of the rotating shaft 3. Under the condition of ensuring the strength of the rotating shaft 3, the space saved by removing the bearings can be used to increase the width of the wire feeding channel 300. When the warp wire passes through the wire feeding channel 300, it is less likely to contact and wear the rotating shaft 3, thereby reducing the possibility of the warp wire breaking.

[0033] Second, the upper bearing 41 and the lower bearing 42 are used to connect the rotating shaft 3 with the upper door ring 1 and the lower door ring 2, which reduces the number of parts in terms of production and assembly, makes production and assembly easier, and can reduce production costs;

[0034] Third, the upper bearing 41 and the lower bearing 42 are moved out from between the upper door ring 1 and the lower door ring 2, so that the selection of bearing models is not restricted by the limited space between the upper door ring 1 and the lower door ring 2, and a bearing with a longer service life can be selected according to actual needs;

[0035] Fourth, since there is no bearing between the upper door ring 1 and the lower door ring 2, the part of the shaft 3 between the upper door ring 1 and the lower door ring 2 can be made into a smooth axis section, and the warp will not be blocked by the shaft 3 and accidentally broken during the process of the warp opening and closing;

[0036] Fifth, the upper bearing 41 and the lower bearing 42 are located outside the wire feeding channel 300, and the heat generated by the rotation of the upper bearing 41 and the lower bearing 42 is easy to dissipate, which is also conducive to improving the service life of the upper bearing 41 and the lower bearing 42;

[0037] Sixth, since dust is generated by friction and wear between the yarn inlet channel 300 and the upper gate ring 1 and the lower gate ring 2 during the warp conveying process, after the upper bearing 41 and the lower bearing 42 are moved out of the yarn inlet channel 300, the possibility of dust accumulation on the upper bearing 41 and the lower bearing 42 can be reduced;

[0038] Seventh, since the upper bearing 41 and the lower bearing 42 are installed at the upper and lower ends of the rotating shaft 3, only the shaft heads at both ends of the rotating shaft 3 need to be finely machined, and the portion between the upper bearing 41 and the lower bearing 42 only needs to meet conventional requirements, which can reduce the machining accuracy of the rotating shaft 3 and reduce the machining cost of the rotating shaft 3;

[0039] Eighth, the upper bearing 41 and the lower bearing 42 are located outside the wire feeding channel 300, and a single bearing can be replaced. Even on the same rotating shaft 3, the upper bearing 41 can be replaced without removing the lower bearing 42, and vice versa, it is more convenient to replace the upper bearing 41 and the lower bearing 42;

[0040] Ninth, the impact of the shuttle 9 on the rotating shaft 3 is a one-to-one action force and reaction force, and then the rotating shaft 3 transmits the impact force to the upper bearing 41 and the lower bearing 42. Therefore, the rotating shaft 3 can more easily transfer the impact force of the shuttle 9 to the upper bearing 41 and the lower bearing 42 evenly, so that the wear conditions and service life of the upper bearing 41 and the lower bearing 42 are similar, which can ensure that the rotating shaft 3 is in a vertical state for a long time, and reduce the possibility of large radial jumps of the shuttle 9.

[0041] In this embodiment, in order to reduce the number of assembly parts, reduce production and assembly costs, and facilitate the assembly and replacement of the upper bearing 41 and the lower bearing 42, the outer ring of the upper bearing 41 can be directly matched with the upper through hole 100, and the outer ring of the lower bearing 42 can be matched with the lower through hole 200. Since it is difficult to achieve the precision requirements of bearing assembly by blind hole processing, through hole processing can, and the upper through hole 100 can be installed from top to bottom or from bottom to top when assembling the upper bearing 41, and the same is true for disassembly, the freedom of assembly and disassembly is higher, and it is not hindered by the upper door ring 1 and the lower door ring 2, so it can be assembled and disassembled separately, which is very convenient. Similarly, the lower through hole 200 is also convenient when assembling and disassembling the lower bearing 42. Since the processing is directly performed on the upper door ring 1 and the lower door ring 2, the processing benchmarks of the upper through hole 100 and the lower through hole 200 are easy to ensure, and the upper bearing 41 and the lower bearing 42 generally use standard parts, so that the cumulative tolerance during the assembly of the shaft is small, the assembly accuracy of all shafts is improved, the assembly position is more accurate, and the rolling track formed is conducive to the smooth and high-speed operation of the shuttle 9, and the radial runout of the shuttle 9 is small. Since the upper bearing 41 is in direct contact with the upper door ring 1, the metal has good thermal conductivity, so the heat generated by the rotation of the upper bearing 41 can be directly absorbed and dissipated by the upper door ring 1, and the heat generated by the rotation of the lower bearing 42 is absorbed and dissipated by the lower door ring 2.

[0042] In order to axially position the upper bearing 41 and the lower bearing 42 , generally the inner ring and the outer ring of the bearing need to be positioned separately, so there are many ways to do this.

[0043] In this embodiment, the upper door ring 1 is provided with a first upper positioning member 61 for axially positioning the upper end of the outer ring of the upper bearing 41, and the lower door ring 2 is provided with a first lower positioning member 62 for axially positioning the lower end of the outer ring of the lower bearing 42. Considering the need for dust prevention, the first upper positioning member 61 can be designed to include an upper pressure cover covering the upper bearing 41, and the upper pressure cover can be fixed to the upper door ring 1 by screws, or can be threadedly connected to the upper through hole, and the first lower positioning member 62 includes a lower pressure cover covering the lower bearing 42, and the lower pressure cover can be fixed to the lower door ring 2 by screws. The first upper positioning member 61 and the first lower positioning member 62 can also be considered to use common parts such as hole retaining springs.

[0044] The upper end of the rotating shaft 3 is provided with an upper shoulder 301 for axially positioning the lower end of the inner ring of the upper bearing 41, and the lower end of the rotating shaft 3 is provided with a lower shoulder 302 for axially positioning the upper end of the inner ring of the lower bearing 42. Considering that dust is easily generated in the wire feeding channel, an upper dust cover 31 can be provided at the lower end of the upper through hole, and a lower dust cover 32 can be provided at the upper end of the lower through hole. In this embodiment, the upper dust cover 31 is sleeved on the rotating shaft 3 and positioned between the upper shoulder 301 and the inner ring of the upper bearing 41, and the lower dust cover 32 is sleeved on the rotating shaft 3 and positioned between the lower shoulder 302 and the inner ring of the lower bearing 42. The upper dust cover 31 and the upper pressure cover form a relatively closed inner cavity, which can be used to store grease for lubricating the upper bearing 41. Similarly, the lower dust cover 32 and the lower pressure cover form a relatively closed inner cavity, which can be used to store grease for lubricating the lower bearing 42.

[0045] It can be understood that in addition to adopting the shoulder structure, a second upper positioning member can be provided at the upper end of the rotating shaft 3 for axially positioning the lower end of the inner ring of the upper bearing 41, and a second lower positioning member can be provided at the lower end of the rotating shaft 3 for axially positioning the upper end of the inner ring of the lower bearing 42. The second upper positioning member and the second lower positioning member can be common parts such as shaft retaining springs.

[0046] Since the bottom plate of the shuttle 9 is generally made of light metal such as aluminum alloy, and the rotating shaft 3 is made of high-strength metal such as steel, a rubber sleeve 5 can be provided on the outer periphery of the rotating shaft 3 to reduce the impact of the shuttle 9 to prevent the two from rigidly colliding. The rubber sleeve 5 is generally injection-molded on the rotating shaft 3 to form an integral body, and the contact area between the two is large and the reliability is high. In order to increase the connection strength between the rubber sleeve 5 and the rotating shaft 3, an annular groove can be provided on the outer periphery of the rotating shaft 3, and the rubber sleeve 5 can be injection-molded in the annular groove. After the rubber sleeve 5 is provided, in order to prevent the upper and lower end surfaces of the rubber sleeve 5 from forming a step structure to affect the upper and lower opening and crossing of the warp, the upper end of the rubber sleeve 5 can be extended into the upper gate ring 1 and the lower end can be extended into the lower gate ring 2, so that the outer periphery of the rubber sleeve 5 is a cylindrical surface with equal diameter, and the upper and lower end surfaces of the rubber sleeve 5 form a step structure hidden in the upper and lower gate rings 2, and the upper and lower opening and crossing of the warp will not be hung and pulled when contacting the outer peripheral side of the rubber sleeve 5, and the rubber sleeve 5 is relatively long, and the contact surface with the bottom plate of the shuttle 9 is large, and the buffering effect is good. Instead of setting the rubber sleeve 5, a rubber pad can also be set on the bottom plate of the shuttle 9. In this case, the width of the wire feeding channel 300 is wider, which is more beneficial for warp wire transportation.

[0047] In this embodiment, since the rotating shaft 3 is axially positioned by the first upper positioning piece 61, the upper bearing 41, the upper dust cover 31, the lower dust cover 32, the lower bearing 42, and the first lower positioning piece 62, the weight of the upper door ring 1 can be supported by the axial positioning of all the rotating shafts 3, that is, the upper door ring 1 and the lower door ring 2 maintain a fixed distance after the axial positioning of the rotating shafts 3. In this way, when the bearings on one or several rotating shafts 3 are replaced, the supporting effect of other rotating shafts 3 and bearings on the upper door ring 1 will not be affected.

[0048] In addition to using a solid shaft, the rotating shaft 3 may also use a hollow shaft to reduce the weight of the machine while meeting the strength requirements.

[0049] In addition to axially positioning the upper end of the outer ring of the upper bearing 41 as in the first embodiment, a third upper positioning member for axially positioning the upper end of the inner ring of the upper bearing 41 may be replaced or added, and similarly, a third lower positioning member for axially positioning the lower end of the inner ring of the lower bearing 42 may be replaced or added. The third upper positioning member and the third lower positioning member may be common parts such as shaft retaining springs, nuts and washers.

[0050] Embodiment 2:

[0051] In addition to maintaining a fixed distance between the upper door ring 1 and the lower door ring 2 by axial positioning of the rotating shaft 3, it is also possible to Figure 3As shown, a support rod 6 is provided between the upper door ring 1 and the lower door ring 2 to maintain a fixed distance between the two. The support rod 6 and the rotating shaft 3 are arranged in the radial direction of the door ring assembly and are located outside the rotating shaft 3, which will not affect the operation of the shuttle 9 or the warp conveying. In this embodiment, the axial load borne by the upper bearing 41 and the lower bearing 42 is greatly reduced, the service life can be further improved, and the requirements for the axial positioning reliability of the bearings are reduced, which can save costs.

[0052] For other contents not described in this embodiment, please refer to Embodiment 1.

[0053] Embodiment three:

[0054] The present invention also provides a plastic circular loom, comprising a frame, a main motor, a shuttle and a gate ring assembly, wherein the gate ring assembly is the gate ring assembly for the plastic circular loom in the above embodiment, and the main motor drives the shuttle to perform circular motion on the rolling track formed by the rotating shaft. The upper bearing and the lower bearing have a long service life and are not easy to be damaged, the use cost of the plastic circular loom is greatly reduced, the frequency of replacement of the upper bearing and the lower bearing is reduced, and the upper bearing and / or the lower bearing are easy to replace, the replacement of the bearing is short, the impact on the production efficiency of the enterprise is reduced, the warp yarn is transported smoothly and orderly, which is conducive to improving the weaving efficiency and quality, and improving the market competitiveness of the product.

[0055] For other contents not described in this embodiment, reference may be made to the above embodiments.

[0056] In addition to the above preferred embodiments, the present invention has other implementation modes. Those skilled in the art may make various changes and modifications based on the present invention. As long as they do not depart from the spirit of the present invention, they should all fall within the scope defined in the claims of the present invention.

Claims

1. A plastic circular loom, comprising a frame, a main motor, a shuttle and a door ring assembly, characterized in that: The main motor drives the shuttle to make circular motion on the rolling track formed by the rotating shaft; the gate ring assembly for the plastic circular loom includes an upper gate ring and a lower gate ring, a plurality of rotating shafts are arranged between the upper gate ring and the lower gate ring, all the rotating shafts are arranged in a ring to form a rolling track for the shuttle to run, and a wire feeding channel for the warp to pass through is formed between two adjacent rotating shafts, the upper end of the rotating shaft is connected to the upper gate ring through an upper bearing, and the lower end of the rotating shaft is connected to the lower gate ring through a lower bearing, the upper gate ring is provided with an upper through hole for convenient installation of the rotating shaft, and the outer ring of the upper bearing is fixedly matched with the upper through hole, and the lower gate ring is provided with a lower through hole for convenient installation of the rotating shaft, and the outer ring of the lower bearing is fixedly matched with the lower through hole ; The upper door ring is provided with a first upper positioning piece for axially positioning the upper end of the upper bearing outer ring, and the lower door ring is provided with a first lower positioning piece for axially positioning the lower end of the lower bearing outer ring; the first upper positioning piece includes an upper pressure cover covering the upper bearing, and the first lower positioning piece includes a lower pressure cover covering the lower bearing; the upper end of the rotating shaft is provided with an upper shaft shoulder or a second upper positioning piece for axially positioning the lower end of the upper bearing inner ring, and the lower end of the rotating shaft is provided with a lower shaft shoulder or a second lower positioning piece for axially positioning the upper end of the lower bearing inner ring; the first upper positioning piece is arranged in parallel with the upper door ring, and the first lower positioning piece is arranged in parallel with the lower door ring; The upper end of the rotating shaft is provided with a third upper positioning piece for axially positioning the upper end of the upper bearing inner ring, and the lower end of the rotating shaft is provided with a third lower positioning piece for axially positioning the lower end of the lower bearing inner ring; the lower end of the upper through hole is provided with an upper dust cover, and the upper end of the lower through hole is provided with a lower dust cover; the outer periphery of the rotating shaft is provided with a rubber sleeve for reducing the impact of the shuttle; the upper door ring and the lower door ring are kept at a fixed distance after being axially positioned by the rotating shaft; or, a support rod is provided between the upper door ring and the lower door ring to maintain a fixed distance between the two, and the part of the rotating shaft located between the upper door ring and the lower door ring is made into a smooth axis section, which will not be blocked by the rotating shaft and accidentally broken during the process of the warp opening and closing.

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