Sizing roller for paper machine
By designing an adjustable rubber-adding and baffle structure, the problem of uneven cloth and glue caused by the fixed length of rubber-adding is solved, the efficiency of papermaking is improved, and the use of rubber sleeves of different sizes is facilitated.
Patent Information
- Application Number
- CN202510470539.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-15
- Publication Date
- 2025-06-06
AI Technical Summary
The existing rubber-adding rollers have fixed lengths and cannot adjust the size, resulting in the inability to use rubber sleeves of different lengths and gaps may appear in the middle, resulting in uneven fabric and adhesive, affecting the efficiency of papermaking.
A rubber-applying roller for papermaking machines is designed. Through the adjustment mechanism, the roller can be moved to both sides, unfolded as a whole, and the length and size of the rubber-applying roller are adjusted. At the same time, the first baffle and the second baffle are deployed to fill the gaps to provide all-round support.
The adjustability of the rubber filling roller is achieved, the appearance of voids is avoided, the uniformity of the cloth and glue is ensured, the efficiency of papermaking is improved, and the use of rubber sleeves of different sizes is facilitated.
Smart Images

Figure CN120099815A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of paper printing, and in particular to a sizing roller for a papermaking machine. Background Art
[0002] In the existing paper printing process, a glue roller is required to apply glue to the paper. However, the existing glue roller is fixed in length and cannot be adjusted in size. Therefore, rubber sleeves of different lengths cannot be used. However, there is generally a gap in the middle of the adjustable length glue roller. When applying glue, uneven force may occur, resulting in uneven glue application, which affects the efficiency of papermaking. Summary of the invention
[0003] To this end, the present invention provides a glue roller for a papermaking machine, which is activated by a user turning a knob to make the adjustment mechanism work, so that the two rollers move to both sides and are unfolded as a whole, thereby adjusting the length of the glue roller. At the same time, when the rollers are unfolded, the first baffle and the second baffle are unfolded, thereby filling the gap and providing all-round support for the rubber sleeve, so as to solve the problem that the existing glue roller has a fixed length and cannot be adjusted in size, so rubber sleeves of different lengths cannot be used. However, a gap will generally appear in the middle of the length-adjustable glue roller, and uneven force may occur during glue application, resulting in uneven glue application, thereby affecting the efficiency of papermaking.
[0004] In order to achieve the above-mentioned object, the present invention provides the following technical solution: a sizing roller for a paper machine, comprising a positioning ring, wherein a positioning frame is fixedly embedded in the positioning ring;
[0005] Rollers, two of which are respectively arranged on both sides of the positioning ring, and transmission rollers are fixedly embedded in the two rollers, and the two transmission rollers are both set as cylindrical structures;
[0006] Two square rods, the two square rods are respectively fixedly connected to the two sides of the two positioning frames, and the two square rods are respectively embedded in the two driving rollers and slide with the two driving rollers respectively;
[0007] An adjusting mechanism, which is arranged on both sides of the positioning frame and is used to adjust the length of the glue roller;
[0008] The adjustment mechanism comprises a transmission shaft, which is embedded in the positioning frame, and the top end of the transmission shaft passes through the outside of the top of the positioning ring. A cavity is provided inside the positioning frame, and the transmission shaft is arranged inside the cavity.
[0009] Preferably, the adjusting mechanism also includes a first bevel gear, which is arranged inside the cavity, and the first bevel gear fixing sleeve is arranged on the outside of the transmission shaft. A second bevel gear is provided inside the cavity, and the second bevel gear is provided at the bottom of the first bevel gear. The first bevel gear is meshed and connected with the second bevel gear. A rotating rod is embedded in the cavity, and the rotating rod is movably connected to the positioning frame through a rolling bearing, and the second bevel gear fixing sleeve is arranged on the outside of the rotating rod.
[0010] Preferably, two transmission rods are provided inside the cavity, and the two transmission rods extend to the outside of the two sides of the two positioning frames respectively. Two first sprockets are provided inside the cavity, and the two first sprockets are fixedly sleeved on the outside of the rotating rod, and the outsides of the two transmission rods are fixedly sleeved with second sprockets, and chains are sleeved on the outsides of the first sprockets and the second sprockets, and the first sprockets and the second sprockets are connected by chain drive.
[0011] Preferably, threaded rods are provided inside the two rollers, and the two threaded rods are respectively fixedly sleeved on the outside of the two transmission rods, and sliding blocks are sleeved on the outside of the two threaded rods. The threaded rods and the sliding blocks are connected by threads, and connecting rods are fixedly connected to the inside of the two sliding blocks, and multiple connecting rods are respectively fixedly connected to both sides of the two transmission rollers.
[0012] Preferably, the adjustment mechanism also includes a plurality of baffles, which are respectively arranged at the top and bottom of the two square rods, a plurality of compression springs are fixedly connected to the inner sides of the baffles, the plurality of compression springs are respectively fixedly connected to the top and bottom of the square rods, a plurality of pull ropes are fixedly connected to the bottoms of the baffles, and the bottom ends of the pull ropes are respectively fixedly connected to the outer ends of a plurality of connecting rods.
[0013] Preferably, multiple connecting frames are fixedly connected on both sides of the positioning frame, two guide wheels are embedded inside the multiple connecting frames, the multiple guide wheels are respectively arranged on the inner sides of multiple pull ropes, and the multiple guide wheels are respectively movably connected to the multiple connecting frames through rolling bearings.
[0014] Preferably, a first side panel is embedded in each of the two rollers, and multiple first side panels are respectively arranged on the front and rear sides of multiple baffles, and second side panels are respectively arranged on the top and bottom of multiple baffles, and the second side panels are embedded in the first side panels, and the first side panels and the second side panels slide with each other, and multiple second side panels are respectively arranged on both sides of multiple baffles, and the second side panels are movably connected to the baffles through hinges, and the first side panels and the second side panels are both made of plastic material.
[0015] Preferably, limit blocks are provided on the inner sides of the plurality of first side panels, a plurality of limit rails are fixedly embedded on both sides of the positioning frame, the plurality of limit blocks are respectively embedded in the plurality of limit rails, the plurality of limit rails are fixedly embedded in the plurality of limit rods, the plurality of limit rods are respectively embedded in the plurality of limit blocks, and the limit rods slide with the limit blocks.
[0016] Preferably, buffer springs are provided inside the two limiting sleeves, and the plurality of buffer springs are respectively fixedly connected to the outsides of the plurality of limiting blocks, and the plurality of buffer springs are respectively sleeved on the outsides of the plurality of limiting rods.
[0017] Preferably, a control knob is fixedly connected to the top of the transmission shaft, and the control knob is movably connected to the positioning ring via a rolling bearing, and a plurality of heat dissipation holes are provided on the outer sides of the two rollers.
[0018] The beneficial effects of the present invention are:
[0019] The user turns the knob to make the adjustment mechanism work, so that the two rollers move to both sides and expand as a whole, so as to adjust the length of the glue roller. At the same time, when the rollers are expanded, the first baffle and the second baffle are expanded to fill the gap and provide all-round support for the rubber sleeve, so as to solve the problem that the existing glue roller has a fixed length and cannot be adjusted in size, so rubber sleeves of different lengths cannot be used. However, there will be a gap in the middle of the rubber roller with adjustable length. When applying glue, uneven force may occur, resulting in uneven glue application, which affects the efficiency of papermaking. The present invention greatly improves the efficiency of applying glue to paper with the glue roller. At the same time, the device adopts a roller with adjustable size, which is convenient for users to put on rubber sleeves of different sizes, bringing great convenience to producers.
[0020] In addition, the device adopts a structural design of a first baffle and a second baffle, so that when the roller contracts, the first baffle and the second baffle are automatically retracted, and when the roller is unfolded, the first baffle and the second baffle are automatically unfolded, making the overall structure more compact and not requiring excessive manual intervention, which brings great convenience to the staff and reduces cost losses. BRIEF DESCRIPTION OF THE DRAWINGS
[0021] In order to more clearly illustrate the implementation methods of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for the implementation methods or the description of the prior art. Obviously, the drawings described below are only exemplary, and for ordinary technicians in this field, other implementation drawings can be derived from the provided drawings without creative work.
[0022] The structures, proportions, sizes, etc. illustrated in this specification are only used to match the contents disclosed in the specification so as to facilitate understanding and reading by persons familiar with the technology. They are not used to limit the conditions under which the present invention can be implemented, and therefore have no substantial technical significance. Any structural modification, change in proportion or adjustment of size, without affecting the effects and purposes that can be achieved by the present invention, should still fall within the scope of the technical contents disclosed by the present invention.
[0023] Figure 1 A schematic diagram of the overall structure provided by the present invention;
[0024] Figure 2 A partial top view and cross-sectional view provided by the present invention;
[0025] Figure 3 A schematic diagram of the three-dimensional structure of the adjustment mechanism provided by the present invention;
[0026] Figure 4 A partial right side view cross-sectional view provided by the present invention;
[0027] Figure 5 The present invention provides Figure 3 A in the enlarged view;
[0028] Figure 6 The present invention provides Figure 4 The enlarged view of point B in the figure;
[0029] Figure 7 A schematic diagram of the three-dimensional structure of the pull rope and guide wheel provided by the present invention;
[0030] Figure 8 A schematic diagram of the three-dimensional structure of the first side panel and the second side panel provided by the present invention;
[0031] In the figure: 1 positioning ring; 2 positioning frame; 3 roller; 4 driving roller; 5 square rod; 6 driving shaft; 7 first bevel gear; 8 second bevel gear; 9 rotating rod; 10 driving rod; 11 first sprocket; 12 second sprocket; 13 chain; 14 threaded rod; 15 sliding block; 16 connecting rod; 17 baffle; 18 compression spring; 19 pull rope; 20 connecting frame; 21 guide wheel; 22 first side plate; 23 second side plate; 24 limit block; 25 limit track; 26 limit rod; 27 buffer spring; 28 control knob; 29 heat dissipation hole; 30 cavity. DETAILED DESCRIPTION
[0032] The preferred embodiments of the present invention are described below in conjunction with the accompanying drawings. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.
[0033] See attached Figure 1 -Attached Figure 8The present invention provides a sizing roller for a paper machine, comprising a positioning ring 1, wherein a positioning frame 2 is fixedly embedded in the positioning ring 1;
[0034] Rollers 3, two rollers 3 are respectively arranged on both sides of the positioning ring 1, and driving rollers 4 are fixedly embedded in the two rollers 3, and the two driving rollers 4 are both set as cylindrical structures;
[0035] Two square rods 5, the two square rods 5 are respectively fixedly connected to the two sides of the two positioning frames 2, and the two square rods 5 are respectively embedded in the two driving rollers 4 and slide with the two driving rollers 4;
[0036] An adjusting mechanism is arranged on both sides of the positioning frame 2, and is used to adjust the length of the glue roller;
[0037] The adjustment mechanism includes a transmission shaft 6, which is embedded in the positioning frame 2, and the top of the transmission shaft 6 passes through the outside of the top of the positioning ring 1. The positioning frame 2 is provided with a cavity 30, and the transmission shaft 6 is arranged inside the cavity 30;
[0038] In this embodiment, the user turns the knob to make the adjustment mechanism work, so that the two rollers 3 move to both sides, so that the whole is unfolded, so as to adjust the length of the glue roller. At the same time, when the rollers 3 are unfolded, the first baffle 17 and the second baffle 17 are unfolded, so as to fill the gap and provide all-round support for the rubber sleeve.
[0039] Among them, in order to achieve the purpose of size adjustment, the present device adopts the following technical solutions: the adjustment mechanism also includes a first bevel gear 7, the first bevel gear 7 is arranged inside the cavity 30, the first bevel gear 7 is fixedly sleeved on the outside of the transmission shaft 6, a second bevel gear 8 is arranged inside the cavity 30, the second bevel gear 8 is arranged at the bottom of the first bevel gear 7, the first bevel gear 7 is meshed and connected with the second bevel gear 8, a rotating rod 9 is embedded in the cavity 30, the rotating rod 9 is movably connected to the positioning frame 2 through a rolling bearing, the second bevel gear 8 is fixedly sleeved on the outside of the rotating rod 9, two transmission rods 10 are arranged inside the cavity 30, the two transmission rods 10 extend to the outside of the two sides of the two positioning frames 2 respectively, and two first sprockets 11 are arranged inside the cavity 30, and the two first sprockets 11 are fixedly sleeved on the outside of the rotating rod 9 , the outer sides of the two transmission rods 10 are fixedly sleeved with a second sprocket 12, the outer sides of the first sprocket 11 and the second sprocket 12 are sleeved with a chain 13, the first sprocket 11 and the second sprocket 12 are driven and connected by the chain 13, and the insides of the two rollers 3 are provided with a threaded rod 14, the two threaded rods 14 are respectively fixedly sleeved on the outer sides of the two transmission rods 10, and the outer sides of the two threaded rods 14 are sleeved with a sliding block 15, the threaded rod 14 and the sliding block 15 are connected by threads, and the inner sides of the two sliding blocks 15 are fixedly connected with a connecting rod 16, and a plurality of connecting rods 16 are respectively fixedly connected to both sides of the two transmission rollers 4, and a control knob 28 is fixedly connected to the top of the transmission shaft 6, and the control knob 28 is movably connected to the positioning ring 1 through a rolling bearing, and a plurality of heat dissipation holes 29 are opened on the outer sides of the two rollers 3;
[0040] The rotation of the knob drives the transmission shaft 6 to rotate, the rotation of the transmission shaft 6 drives the first bevel gear 7 to rotate, the rotation of the first bevel gear 7 drives the second bevel gear 8 and the rotating rod 9 to rotate, the rotation of the rotating rod 9 drives the two first sprocket wheels 11 to rotate, the rotation of the first sprocket wheel 11 drives the two second sprocket wheels 12 to rotate, the rotation of the second sprocket wheel 12 drives the two transmission rods 10 to rotate, the rotation of the two transmission rods 10 drives the multiple threaded rods 14 to rotate, the rotation of the multiple threaded rods 14 drives the multiple sliding blocks 15 to move outward, the movement of the multiple sliding blocks 15 drives the multiple connecting rods 16 to move, the movement of the multiple connecting rods 16 drives the two transmission rollers 4 to move outward, so as to adjust the gap between the two rollers 3;
[0041] Among them, in order to achieve the purpose of gap filling, the present device is implemented by the following technical solutions: the adjusting mechanism also includes a plurality of baffles 17, the plurality of baffles 17 are respectively arranged at the top and bottom of the two square rods 5, the inner sides of the plurality of baffles 17 are fixedly connected with a plurality of compression springs 18, the plurality of compression springs 18 are respectively fixedly connected to the top and bottom of the square rod 5, the bottoms of the plurality of baffles 17 are fixedly connected with pull ropes 19, the bottom ends of the plurality of pull ropes 19 are respectively fixedly connected to the outer ends of the plurality of connecting rods 16, the two sides of the positioning frame 2 are fixedly connected with a plurality of connecting frames 20, two guide wheels 21 are embedded in the plurality of connecting frames 20, the plurality of guide wheels 21 are respectively arranged at the inner sides of the plurality of pull ropes 19, the plurality of guide wheels 21 are respectively movably connected to the plurality of connecting frames 20 through rolling bearings, the two rollers 3 are respectively embedded with a first side plate 22, the plurality of first side plates 22 are respectively arranged at the front and rear sides of the plurality of baffles 17, the top and bottom of the plurality of baffles 17 The first and second side plates 22 and 23 are each provided with a second side plate 23, the second side plate 23 is embedded in the first side plate 22, the first and second side plates 23 slide with each other, the plurality of second side plates 23 are respectively arranged on both sides of the plurality of baffles 17, the second side plates 23 are movably connected with the baffles 17 through hinges, the first and second side plates 22 and 23 are both made of plastic material, the inner sides of the plurality of first side plates 22 are each provided with a limit block 24, the two sides of the positioning frame 2 are each fixedly embedded with a plurality of limit rails 25, the plurality of limit blocks 24 are respectively embedded in the plurality of limit rails 25, the plurality of limit rails 25 are each fixedly embedded with a limit rod 26, the plurality of limit rods 26 are respectively embedded in the plurality of limit blocks 24, the limit rod 26 slides with the limit blocks 24, the two limit sleeves are each provided with a buffer spring 27, the plurality of buffer springs 27 are respectively fixedly connected to the outer sides of the plurality of limit blocks 24, and the plurality of buffer springs 27 are respectively sleeved on the outer sides of the plurality of limit rods 26;
[0042] When the multiple connecting rods 16 move outward, the multiple pull ropes 19 will be loosened, and the relaxation of the multiple pull ropes 19 will cause the multiple compression springs 18 to rebound, so that the multiple baffles 17 move outward to fill the upper and lower gaps. At the same time, the outward movement of the multiple baffles 17 will drive the multiple second side panels 23 to unfold. When the multiple second side panels 23 are unfolded, the multiple first side panels 22 are not hindered, so that the multiple buffer springs 27 rebound, so that the multiple first side panels 22 move outward, so that the first side panels 22 and the second side panels 23 fill the front and rear gaps.
[0043] The use process of the present invention is as follows: the user turns the knob to make the adjustment mechanism work, so that the two rollers 3 move to both sides and expand as a whole, so as to adjust the length of the glue roller. At the same time, when the rollers 3 are expanded, the first baffle 17 and the second baffle 17 are expanded, so as to fill the gap and provide all-round support for the rubber sleeve. The knob is rotated to drive the transmission shaft 6 to rotate, and the transmission shaft 6 rotates to drive the first bevel gear 7 to rotate. The first bevel gear 7 rotates to drive the second bevel gear 8 and the rotating rod 9 to rotate. The rotating rod 9 rotates to drive the two first sprocket wheels 11 to rotate. The first sprocket wheel 11 rotates to drive the two second sprocket wheels 12 to rotate. The second sprocket wheel 12 rotates to drive the two transmission rods 10 to rotate. The two transmission rods 10 rotate to drive the multiple threaded rods 14 to rotate. The rotation of 14 drives the multiple sliding blocks 15 to move outward, and the movement of the multiple sliding blocks 15 drives the multiple connecting rods 16 to move, and the movement of the multiple connecting rods 16 drives the two driving rollers 4 to move outward, so as to adjust the gap between the two rollers 3. When the multiple connecting rods 16 move outward, they will drive the multiple pull ropes 19 to relax, and the relaxation of the multiple pull ropes 19 will cause the multiple compression springs 18 to rebound, so that the multiple baffles 17 move outward to fill the upper and lower gaps. At the same time, the outward movement of the multiple baffles 17 will drive the multiple second side panels 23 to unfold, and when the multiple second side panels 23 are unfolded, the multiple first side panels 22 are not hindered, so that the multiple buffer springs 27 rebound, so that the multiple first side panels 22 move outward, so that the first side panels 22 and the second side panels 23 fill the front and rear gaps.
[0044] The above is only a preferred embodiment of the present invention. Any person skilled in the art may modify the present invention by using the above technical solution or modify it into an equivalent technical solution. Therefore, any simple modification or equivalent replacement made according to the technical solution of the present invention shall fall within the scope of protection claimed by the present invention.
Claims
1. A sizing roller for a paper machine, characterized in that: include A positioning ring (1), wherein a positioning frame (2) is fixedly embedded inside the positioning ring (1); Rollers (3), the two rollers (3) are respectively arranged on both sides of the positioning ring (1), and transmission rollers (4) are fixedly embedded inside the two rollers (3), and the two transmission rollers (4) are both cylindrical structures; Two square rods (5), the two square rods (5) are respectively fixedly connected to the two sides of the two positioning frames (2), and the two square rods (5) are respectively embedded in the two driving rollers (4) and slide with the two driving rollers (4); An adjusting mechanism, the adjusting mechanism being arranged on both sides of the positioning frame (2), and the adjusting mechanism being used to adjust the length of the glue roller; The adjustment mechanism comprises a transmission shaft (6), the transmission shaft (6) is embedded in the positioning frame (2), the top end of the transmission shaft (6) passes through the outside of the top of the positioning ring (1), a cavity (30) is provided inside the positioning frame (2), and the transmission shaft (6) is arranged inside the cavity (30).
2. A sizing roller for a paper machine according to claim 1, characterized in that: The adjustment mechanism further comprises a first bevel gear (7), the first bevel gear (7) being arranged inside the cavity (30), the first bevel gear (7) being fixedly sleeved on the outside of the transmission shaft (6), a second bevel gear (8) being arranged inside the cavity (30), the second bevel gear (8) being arranged at the bottom of the first bevel gear (7), the first bevel gear (7) being meshingly connected with the second bevel gear (8), a rotating rod (9) being embedded inside the cavity (30), the rotating rod (9) being movably connected with the positioning frame (2) via a rolling bearing, and the second bevel gear (8) being fixedly sleeved on the outside of the rotating rod (9).
3. The sizing roller for a paper machine according to claim 1, characterized in that: Two transmission rods (10) are arranged inside the cavity (30), and the two transmission rods (10) extend to the outside of the two sides of the two positioning frames (2) respectively. Two first sprockets (11) are arranged inside the cavity (30), and the two first sprockets (11) are fixedly sleeved on the outside of the rotating rod (9). A second sprocket (12) is fixedly sleeved on the outside of the two transmission rods (10), and a chain (13) is sleeved on the outside of the first sprocket (11) and the second sprocket (12), and the first sprocket (11) and the second sprocket (12) are driven and connected by the chain (13).
4. The sizing roller for a paper machine according to claim 1, characterized in that: The two rollers (3) are each provided with a threaded rod (14) inside, the two threaded rods (14) are respectively fixedly sleeved on the outside of the two transmission rods (10), the two threaded rods (14) are each sleeved on the outside of the two threaded rods (14), the threaded rod (14) and the sliding block (15) are connected via threads, the inside of the two sliding blocks (15) are each fixedly connected with a connecting rod (16), and a plurality of the connecting rods (16) are respectively fixedly connected to both sides of the two transmission rollers (4).
5. The sizing roller for a paper machine according to claim 1, characterized in that: The adjustment mechanism further comprises a plurality of baffles (17), wherein the plurality of baffles (17) are respectively arranged at the top and bottom of the two square rods (5), wherein the inner sides of the plurality of baffles (17) are fixedly connected with a plurality of compression springs (18), wherein the plurality of compression springs (18) are respectively fixedly connected to the top and bottom of the square rods (5), wherein the bottoms of the plurality of baffles (17) are fixedly connected with pull ropes (19), wherein the bottom ends of the plurality of pull ropes (19) are respectively fixedly connected with the outer ends of the plurality of connecting rods (16).
6. The sizing roller for a paper machine according to claim 1, characterized in that: A plurality of connecting frames (20) are fixedly connected to both sides of the positioning frame (2), two guide wheels (21) are embedded inside the plurality of connecting frames (20), the plurality of guide wheels (21) are respectively arranged inside the plurality of pull ropes (19), and the plurality of guide wheels (21) are respectively movably connected to the plurality of connecting frames (20) via rolling bearings.
7. The sizing roller for a paper machine according to claim 2, characterized in that: A first side plate (22) is embedded in the two rollers (3), and the first side plates (22) are respectively arranged on the front and rear sides of the baffles (17). The tops and bottoms of the baffles (17) are respectively provided with second side plates (23). The second side plates (23) are embedded in the first side plates (22). The first side plates (22) and the second side plates (23) slide with each other. The second side plates (23) are respectively arranged on the two sides of the baffles (17). The second side plates (23) are movably connected to the baffles (17) through hinges. The first side plates (22) and the second side plates (23) are both made of plastic material.
8. The sizing roller for a paper machine according to claim 7, characterized in that: A plurality of first side plates (22) are each provided with a limit block (24) on their inner sides, a plurality of limit rails (25) are fixedly embedded on both sides of the positioning frame (2), a plurality of the limit blocks (24) are respectively embedded in a plurality of limit rails (25), a plurality of limit rails (25) are each fixedly embedded in a plurality of limit rods (26), a plurality of limit rods (26) are respectively embedded in a plurality of limit blocks (24), and the limit rods (26) slide with the limit blocks (24).
9. A sizing roller for a paper machine according to claim 8, characterized in that: A buffer spring (27) is provided inside each of the two limiting sleeves; the plurality of buffer springs (27) are respectively fixedly connected to the outside of the plurality of limiting blocks (24); and the plurality of buffer springs (27) are respectively sleeved on the outside of the plurality of limiting rods (26).
10. The sizing roller for a paper machine according to claim 1, characterized in that: A control knob (28) is fixedly connected to the top of the transmission shaft (6), and the control knob (28) is movably connected to the positioning ring (1) via a rolling bearing. Multiple heat dissipation holes (29) are provided on the outer sides of the two rollers (3).