Upper rotary traction mechanism of film blowing machine

Abstract

The invention discloses an upper rotating traction mechanism of a film blowing machine. The upper rotating traction mechanism comprises a rotating base, a bracket and a rotating mechanism, the rotary base is driven by a driving device to rotate forwards and backwards; a traction roller is arranged below an upper mounting part; the rotating mechanism comprises a lower bearing seat, a driving fluted disc, a lower rotating shaft, an upper bearing seat, a driven fluted disc, an upper rotating shaft and the like, and a driving shaft and a driven shaft are driven through gears and respectively drive the lower swing roller assembly and the upper swing roller assembly to rotate and deflect reversely. The mechanism takes the rotating base as a power source, a motor does not need to be independently configured for the swing roller assembly, and the driving structure is simplified; the single driving fluted disc achieves synchronous reverse deflection of the lower swing roller assembly and the upper swing roller assembly through a gear transmission system, the problem that synchronous control over multiple motors is difficult is solved, and traction stability is guaranteed. Equipment manufacturing cost and maintenance difficulty are reduced, film thickness uniformity and surface quality are improved, and production efficiency and economic benefits are improved.

Description

Technical Field

[0001] The invention relates to the technical field of film blowing machines, and in particular to an upper rotating traction mechanism of a film blowing machine. Background Art

[0002] In the production process of film blowing machines, the upper rotary traction mechanism plays a key role, and its performance directly affects the production quality and efficiency of the film. At present, the existing upper rotary drive structure of film blowing machines generally has the problem of complex drive structure. In order to realize the rotation and swinging movement of multiple swing roller assemblies, it is often necessary to match multiple motors to drive them separately. This multi-motor drive method not only increases the manufacturing cost and maintenance difficulty of the equipment, but also makes it difficult to achieve precise synchronous control between multiple motors during actual operation. Once the synchronization between the motors deviates, the traction process will become unstable, which will affect the thickness uniformity and surface quality of the film, reduce the yield rate of the film product, and bring economic losses to the production company. Therefore, there is an urgent need for a rotary traction mechanism on a film blowing machine that can simplify the drive structure and realize the synchronous and stable operation of the swing roller assemblies. Summary of the Invention

[0003] In view of the deficiencies in the background technology, the present invention provides an upper rotating traction mechanism for a film blowing machine.

[0004] The technical solution adopted by the present invention is: an upper rotating traction mechanism of a film blowing machine, comprising a rotating base, a bracket and a rotating mechanism; The rotating base can realize forward and reverse rotation under the drive of the driving device. A mounting portion is provided on the rotating base, and a traction roller is provided below the mounting portion. The rotating mechanism includes a lower bearing seat fixedly connected to the mounting portion, a driving gear plate fixed to the lower bearing seat, a lower rotating shaft rotatably connected to the lower bearing seat, an upper bearing seat fixed to the bracket, a driven gear plate fixed to the upper bearing seat, an upper rotating shaft rotatably connected to the upper bearing seat, a frame connected between the upper rotating shaft and the lower rotating shaft, a driving shaft and a driven shaft rotatably connected to the frame, a lower swing roller assembly fixedly connected to the lower rotating shaft, and an upper swing roller assembly fixedly connected to the upper rotating shaft; The driving shaft and the driven shaft are connected through a driving gear and a driven gear. A first transmission gear and a second transmission gear are fixed to the driving shaft, and a third transmission gear and a fourth transmission gear are fixed to the driven shaft. The first transmission gear is meshed with the driving gear plate for transmission, and the fourth transmission gear is meshed with the driven gear plate for transmission. The lower swing roller assembly includes a lower swing bracket, a lower swing roller arranged on the lower swing bracket, and a lower half gear arranged on the lower swing bracket, wherein the lower half gear is meshed with the second transmission gear for transmission; The upper swing roller assembly includes an upper swing bracket, an upper swing roller arranged on the upper swing bracket, and an upper half gear arranged on the upper swing bracket. The upper half gear is in meshing transmission with the third transmission gear.

[0005] Further, the rotary base includes a base frame, a large gear ring rotatably arranged on the base frame, and a traction roller bracket fixed on the large gear ring. The driving device is fixed on the base frame and includes a driving motor, a speed reducer connected to the output end of the driving motor, and an output gear connected to the output end of the speed reducer. The output gear is in meshing transmission with the large gear ring. The traction roller is arranged on side plates on both sides of the traction roller bracket, and the mounting part is fixed on the side plate above the traction roller.

[0006] Further, the traction roller includes a driven roller, a driving roller rotatably connected to the side plates at both ends, a reduction motor for driving the driving roller to rotate, and an adjusting component for driving the driven roller to approach or move away from the driving roller.

[0007] Further, there are two adjusting components, which are respectively arranged on the side plates on both sides of the base frame. The adjusting component includes an adjusting cylinder fixed on the side plate through a vertical plate, a slider connected to the output end of the adjusting cylinder, and a slide rail in sliding fit with the slider. Both ends of the driven roller are rotatably connected to the slider.

[0008] Further, a discharge roller is arranged at one end of the bracket. A transition roller is connected to the frame between the upper swing roller and the lower swing roller. A connecting arm extending towards the discharge roller is provided on the side plate. A first anti-wrinkle roller and a second anti-wrinkle roller are arranged on the connecting arm. The second anti-wrinkle roller is located at the upper left oblique of the first anti-wrinkle roller. The transition roller is located at the upper left oblique of the second anti-wrinkle roller. The discharge roller is located at the upper left oblique of the transition roller.

[0009] Further, the included angle between a first connection line between the center of the discharge roller and the center of the transition roller and a second connection line between the center of the transition roller and the center of the second anti-wrinkle roller is 110 - 120°. The included angle between a third connection line between the center of the second anti-wrinkle roller and the center of the first anti-wrinkle roller and the second connection line is 165 - 175°.

[0010] Further, the bracket includes two "ㄇ" - shaped frames arranged side by side and connecting rods arranged at both ends of the "ㄇ" - shaped frames for connecting the two "ㄇ" - shaped frames. The mounting part is fixed in the middle of the "ㄇ" - shaped frame.

[0011] Further, both the upper swing roller and the lower swing roller are air - cooled guide rollers, and a plurality of air outlet holes are evenly distributed on the air - cooled guide rollers.

[0012] Further, cold air blowers are connected to both ends of the upper swing roller and the lower swing roller. The cold air blowers are connected to the inner cavity of the air - cooled guide rollers through air ducts, and the cold air blowers are fixed on the upper swing bracket through blower mounting plates.

[0013] Furthermore, the arc of the upper half gear and the lower half gear is 35-50°.

[0014] The beneficial effects of the present invention are: 1. Abandoning the complex mode of traditional multi-motor drive, the original rotating base is used as the power source. There is no need to match the swing roller assembly with a separate motor, which greatly simplifies the overall drive structure, reduces the manufacturing complexity of the equipment, and reduces hardware costs and installation space. 2. A single active geared disc, through a gear drive system, synchronously drives the lower and upper swing roller assemblies in counter-rotating and yaw motion, effectively avoiding the difficulty of synchronously controlling multiple motors and ensuring a highly stable pulling process. This stable pulling process ensures uniform force on the film during stretching, significantly improving film thickness uniformity and surface quality, increasing the yield rate of film products and enhancing the market competitiveness of the company's products. 3. The simplified drive structure makes equipment maintenance more convenient and efficient, reduces maintenance costs and downtime caused by multi-motor system failures, improves production efficiency, and creates more economic benefits for the enterprise.

[0015] In addition to the objects, features and advantages described above, the present invention has other objects, features and advantages.

[0016] The present invention will be described in further detail below with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a structural schematic diagram of the present invention.

[0018] Figure 2 for Figure 1 Enlarged schematic diagram of point A in the middle.

[0019] Figure 3 It is a cross-sectional schematic diagram of the present invention.

[0020] Figure 4 It is a structural diagram of the rotating mechanism.

[0021] Figure 5 This is a structural diagram of the rotating structure from another perspective.

[0022] Figure 6 This is a schematic diagram after the frame and upper and lower swing roller assemblies are hidden.

[0023] Figures 1-6Chinese: 1. Rotating base; 2. Support; 3. Rotating mechanism; 4. Driving device; 5. Mounting part; 6. Traction roller; 7. Lower bearing block; 8. Driving gear disc; 9. Lower rotating shaft; 10. Upper bearing block; 11. Driven gear disc; 12. Upper rotating shaft; 13. Frame; 14. Driving shaft; 15. Driven shaft; 16. Lower swing roller assembly; 17. Upper swing roller assembly; 18. Driving gear; 19. Driven gear; 20. First transmission gear; 21. Second transmission gear; 22. Third transmission gear; 23. Fourth transmission gear; 24. Lower swing support; 25. Lower swing roller; 26. Lower half gear; 27. Upper swing support; 28. Upper swing roller; 29. Upper half gear; 30. Base frame; 31. Large gear ring; 32. Traction roller support; 33. Driving motor; 34. Reducer; 35. Output gear; 36. Side plate; 37. Driven roller; 38. Driving roller; 39. Speed reducing motor; 40. Adjusting component; 41. Vertical plate; 42. Adjusting cylinder; 43. Slide block; 44. Slide rail; 45. Discharge roller; 46. Transition roller; 47. Connecting arm; 48. First anti-wrinkle roller; 49. Second anti-wrinkle roller; 50. First connection line; 51. Second connection line; 52. Third connection line; 53. "冂"-shaped frame; 54. Connecting rod; 55. Air outlet hole; 56. Cold air blower; 57. Air duct; 58. Blower mounting plate. Detailed implementation manners

[0024] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts shall fall within the protection scope of the present invention.

[0025] It should be noted that if there are directional indications (such as up, down, left, right, front, back,...) involved in the embodiments of the present invention, then such directional indications are only used to explain the relative positional relationship and movement conditions between components in a specific posture (as shown in the accompanying drawings). If this specific posture changes, then such directional indications will also change accordingly.

[0026] [[ID=1 Eleven]]The present invention provides an upper rotating traction mechanism for a film blowing machine.

[0027] In this embodiment, referring to Figure 1-6 , the upper rotating traction mechanism of this film blowing machine includes a rotating base 1, a support 2 and a rotating mechanism 3; The rotating base 1 can rotate forward and backward under the drive of the driving device 4. An installation part 5 is provided on the rotating base, and a traction roller 6 is provided below the installation part 5; The rotating mechanism 3 includes a lower bearing seat 7 fixedly connected to the mounting portion, a driving gear plate 8 fixed to the lower bearing seat 7, a lower rotating shaft 9 rotatably connected to the lower bearing seat, an upper bearing seat 10 fixed to the bracket, a driven gear plate 11 fixed to the upper bearing seat, an upper rotating shaft 12 rotatably connected to the upper bearing seat, a frame 13 connected between the upper rotating shaft and the lower rotating shaft, a driving shaft 14 and a driven shaft 15 rotatably connected to the frame 13, a lower swing roller assembly 16 fixedly connected to the lower rotating shaft, and an upper swing roller assembly 17 fixedly connected to the upper rotating shaft. The driving shaft and the driven shaft are connected by a driving gear 18 and a driven gear 19. A first transmission gear 20 and a second transmission gear 21 are fixed to the driving shaft, and a third transmission gear 22 and a fourth transmission gear 23 are fixed to the driven shaft. The first transmission gear meshes with the driving gear plate, and the fourth transmission gear meshes with the driven gear plate. The lower swing roller assembly includes a lower swing bracket 24, a lower swing roller 25 provided on the lower swing bracket, and a lower half gear 26 provided on the lower swing bracket, wherein the lower half gear is meshed with the second transmission gear for transmission; The upper swing roller assembly includes an upper swing bracket 27, an upper swing roller 28 provided on the upper swing bracket, and an upper half gear 29 provided on the upper swing bracket. The upper half gear is engaged with the third transmission gear for transmission.

[0028] In the above technical solution, a gear transmission system achieves counter-rotational yaw of the lower and upper swing roller assemblies. Specifically, the rotation of the rotating base drives the driving gear on the lower bearing seat, which in turn rotates the driving shaft. The driving and driven shafts mesh with the driving gear, achieving counter-rotation. The transmission gears on the driving and driven shafts respectively mesh with the lower half gear of the lower swing roller assembly and the upper half gear of the upper swing roller assembly, thereby achieving synchronous counter-yaw of the lower and upper swing rollers.

[0029] The above technical solution has the following advantages: Simplified drive structure: There is no need to configure an independent motor for the swing roller assembly. The swing roller is deflected by using the rotational power of the rotating base, which reduces the complexity and cost of the equipment.

[0030] Good synchronization: The gear transmission system driven by a single active gear plate ensures that the swinging movements of the lower and upper swing rollers are highly synchronized, avoiding the difficulty of synchronous control when multiple motors are driven.

[0031] Stable traction: The synchronous reverse-deflection oscillating roller assembly ensures uniform force on the film during traction, improving the uniformity of film thickness and surface quality, and increasing product yield.

[0032] The specific operating principle is as follows: The rotating base rotates forward or reverse under the action of the drive device, driving the lower bearing seat fixed to its upper mounting portion to rotate, and the driving gear plate fixed to the lower bearing seat rotates accordingly. The driving gear plate drives the driving shaft and driven shaft to rotate in the opposite direction, thereby driving the upper and lower swing roller assemblies to rotate synchronously in the opposite direction.

[0033] Specifically, the rotating base includes a base frame 30, a large gear ring 31 rotatably set on the base frame 30, and a traction roller bracket 32 fixed on the large gear ring 31. The driving device is fixed on the base frame, and includes a driving motor 33, a reducer 34 connected to the output end of the driving motor 33, and an output gear 35 connected to the output end of the reducer 34. The output gear 35 is engaged with the large gear ring for transmission. The traction roller is set on the side plates 36 on both sides of the traction roller bracket, and the mounting portion is fixed on the side plates 36 above the traction roller.

[0034] In this embodiment, the rotating base is driven by a drive motor and a reducer on the chassis, which drives the output gear. The output gear meshes with the large ring gear, thereby driving the large ring gear and the traction roller bracket mounted on it to rotate. This structure enables the rotating base to rotate forward and reverse by rotating the drive motor, and the meshing transmission between the large ring gear and the output gear provides stable rotational power.

[0035] Specifically, the traction roller includes a driven roller 37, a driving roller 38 whose two ends are rotatably connected to the side plates, a reduction motor 39 for driving the driving roller to rotate, and an adjustment component 40 for driving the driven roller to move closer to or away from the driving roller.

[0036] In this embodiment, the traction rollers are driven by a reduction motor to rotate the active roller, while the passive roller, controlled by an adjustment assembly, can be moved closer or further away from the active roller, thereby adjusting the gap between the two rollers. As a film passes between the two rollers, the rotation of the active roller provides traction, while the passive roller cooperates with the active roller to clamp and convey the film. The adjustment assembly adjusts the gap between the passive and active rollers based on film thickness and material, ensuring effective clamping for films of varying specifications and preventing film deformation due to slippage or excessive squeezing.

[0037] Specifically, there are two adjustment components 40, which are respectively arranged on the side panels on both sides of the base frame. The adjustment components 40 include an adjustment cylinder 42 fixed to the side panel through a vertical plate 41, a slider 43 connected to the output end of the adjustment cylinder, and a slide rail 44 slidingly matched with the slider 43. The two ends of the driven roller are rotationally connected to the slider.

[0038] In this embodiment, the adjustment assembly uses an adjustment cylinder to push the slider on the slide rail, thereby moving the driven roller toward or away from the active roller. The adjustment cylinders on both sides operate synchronously, ensuring that both ends of the driven roller move synchronously and maintain parallelism with the active roller.

[0039] Specifically, a discharge roller 45 is provided at one end of the bracket. A transition roller 46 is connected to the frame between the upper swing roller and the lower swing roller. A connecting arm 47 extending towards the discharge roller is provided on the side plate. A first anti-wrinkle roller 48 and a second anti-wrinkle roller 49 are provided on the connecting arm 47. The second anti-wrinkle roller is located at the upper left oblique position of the first anti-wrinkle roller. The transition roller is located at the upper left oblique position of the second anti-wrinkle roller. The discharge roller is located at the upper left oblique position of the transition roller.

[0040] In this embodiment, as Figure 3 shown, the upper left oblique position in this embodiment specifically refers to Figure 3 the relative position under a specific perspective. After the film is output from the traction roller, it sequentially passes through the first anti-wrinkle roller, the second anti-wrinkle roller, the lower swing roller, the transition roller, and the upper swing roller, and finally is output through the discharge roller. The transition roller is located at the upper left oblique position of the second anti-wrinkle roller, the second anti-wrinkle roller is located at the upper left oblique position of the first anti-wrinkle roller, and the discharge roller is located at the upper left oblique position of the transition roller. This stepped roller arrangement enables the film to form a stable tension distribution and bending path during transportation. With the swinging function of the upper and lower swing rollers, the film experiences multiple bends in different directions during transportation, effectively eliminating the wrinkles on the film surface and improving the flatness of the film.

[0041] Specifically, the included angle between the first connection line 50 between the center of the discharge roller and the center of the transition roller and the second connection line 51 between the center of the transition roller and the center of the second anti-wrinkle roller is 110 - 120°. The included angle between the third connection line 52 between the center of the second anti-wrinkle roller and the center of the first anti-wrinkle roller and the second connection line is 165 - 175°.

[0042] In this embodiment, by defining the included angle between the first connection line between the center of the discharge roller and the center of the transition roller and the second connection line between the center of the transition roller and the center of the second anti-wrinkle roller to be 110 - 120°, and the included angle between the third connection line between the center of the second anti-wrinkle roller and the center of the first anti-wrinkle roller and the second connection line to be 165 - 175°, a more stable tension distribution and bending path are formed for the film during transportation.

[0043] Specifically, the bracket includes two juxtaposed "冂"-shaped frames 53 and connecting rods 54 provided at both ends of the "冂"-shaped frames for connecting the two "冂"-shaped frames. The mounting portion is fixed in the middle of the "冂"-shaped frame.

[0044] In this embodiment, the bracket adopts two juxtaposed "冂"-shaped frames, which are connected by connecting rods at both ends to form an integral frame structure. This structure not only ensures the strength and stability of the bracket but also provides a reasonable installation space for the rotating mechanism and other components. <(

[0045] Specifically, both the upper swing roller and the lower swing roller are air-cooled guide rollers, and a plurality of air outlet holes 55 are evenly distributed on the air-cooled guide rollers.

[0046] In this embodiment, the upper and lower swing rollers are air-cooled guide rollers, and the roller surfaces are evenly distributed with a plurality of air outlet holes. When cold air passes through the roller cavity, it is blown out from the air outlet holes to cool the film in contact with the roller surface.

[0047] Specifically, both ends of the upper swing roller and the lower swing roller are connected to a cold air blower 56 , and the cold air blower 56 is connected to the inner cavity of the air-cooled guide roller through an air duct 57 , and the cold air blower is fixed to the upper swing bracket through a blower mounting plate 58 .

[0048] In this embodiment, cooling fans are connected to both ends of the upper and lower rollers. These fans deliver cold air through air ducts into the inner cavity of the cooling guide roller, rapidly cooling the film as it passes through the upper and lower rollers. The fan mounting plate provides a stable support structure for the cooling fans.

[0049] Specifically, the arc angle of the upper half gear and the lower half gear is 35-50°.

[0050] In this embodiment, the curvature of the upper and lower half gears is designed to be 35-50°. This gear structure with limited curvature cooperates with the transmission gear to enable the lower and upper swing roller assemblies to achieve a limited angle of yaw motion during rotation.

[0051] Technical personnel should note: Although the present invention has been described according to the above specific implementation methods, the concept of the present invention is not limited to this invention. Any modification using the concept of the present invention will be included in the scope of protection of this patent right.

Claims

1. An upper rotating traction mechanism of a film blowing machine, characterized in that: It includes a rotating base, a bracket and a rotating mechanism; The rotating base can realize forward and reverse rotation under the drive of the driving device. A mounting portion is provided on the rotating base, and a traction roller is provided below the mounting portion. The rotating mechanism includes a lower bearing seat fixedly connected to the mounting portion, a driving gear plate fixed to the lower bearing seat, a lower rotating shaft rotatably connected to the lower bearing seat, an upper bearing seat fixed to the bracket, a driven gear plate fixed to the upper bearing seat, an upper rotating shaft rotatably connected to the upper bearing seat, a frame connected between the upper rotating shaft and the lower rotating shaft, a driving shaft and a driven shaft rotatably connected to the frame, a lower swing roller assembly fixedly connected to the lower rotating shaft, and an upper swing roller assembly fixedly connected to the upper rotating shaft; The driving shaft and the driven shaft are connected through a driving gear and a driven gear. A first transmission gear and a second transmission gear are fixed to the driving shaft, and a third transmission gear and a fourth transmission gear are fixed to the driven shaft. The first transmission gear is meshed with the driving gear plate for transmission, and the fourth transmission gear is meshed with the driven gear plate for transmission. The lower swing roller assembly includes a lower swing bracket, a lower swing roller arranged on the lower swing bracket, and a lower half gear arranged on the lower swing bracket, wherein the lower half gear is meshed with the second transmission gear for transmission; The upper swing roller assembly includes an upper swing bracket, an upper swing roller arranged on the upper swing bracket, and an upper half gear arranged on the upper swing bracket. The upper half gear is meshed with the third transmission gear for transmission.

2. The upper rotary traction mechanism of the film blowing machine according to claim 1, characterized in that: The rotating base includes a base frame, a large gear ring rotatably arranged on the base frame, and a traction roller bracket fixed on the large gear ring. The driving device is fixed on the base frame, and includes a driving motor, a reducer connected to the output end of the driving motor, and an output gear connected to the output end of the reducer. The output gear is engaged with the large gear ring for transmission. The traction roller is arranged on the side plates on both sides of the traction roller bracket, and the mounting portion is fixed on the side plate above the traction roller.

3. The upper rotating traction mechanism of the film blowing machine according to claim 2, characterized in that: The traction roller includes a driven roller, a driving roller whose two ends are rotatably connected to the side plates, a reduction motor for driving the driving roller to rotate, and an adjustment component for driving the driven roller to move closer to or away from the driving roller.

4. The upper rotating traction mechanism of the film blowing machine according to claim 3, characterized in that: There are two adjustment components, which are respectively arranged on the side panels on both sides of the base frame. The adjustment components include an adjustment cylinder fixed to the side panel through a vertical panel, a slider connected to the output end of the adjustment cylinder, and a slide rail that slides with the slider. The two ends of the driven roller are rotationally connected to the slider.

5. The upper rotary traction mechanism of the film blowing machine according to claim 2, characterized in that: A discharge roller is provided on one end of the bracket, a transition roller is connected to the frame between the upper swing roller and the lower swing roller, the side plate has a connecting arm extending toward one side of the discharge roller, a first anti-wrinkle roller and a second anti-wrinkle roller are provided on the connecting arm, the second anti-wrinkle roller is located obliquely above and to the left of the first anti-wrinkle roller, the transition roller is located obliquely above and to the left of the second anti-wrinkle roller, and the discharge roller is located obliquely above and to the left of the transition roller.

6. The upper rotary traction mechanism of the film blowing machine according to claim 5, characterized in that: The angle between the first connecting line between the center of the discharge roller and the center of the transition roller and the second connecting line between the center of the transition roller and the center of the second anti-wrinkle roller is 110-120°, and the angle between the third connecting line between the center of the second anti-wrinkle roller and the center of the first anti-wrinkle roller and the second connecting line is 165-175°.

7. The upper rotary traction mechanism of the film blowing machine according to claim 5, characterized in that: The bracket includes two "冂"-shaped frames arranged side by side and connecting rods arranged at both ends of the "冂"-shaped frames for connecting the two "冂"-shaped frames, and the mounting part is fixed in the middle of the "冂"-shaped frame.

8. The upper rotary traction mechanism of the film blowing machine according to claim 1, characterized in that: Both the upper swing roller and the lower swing roller are air-cooled guide rollers, and a number of air outlet holes are evenly distributed on the air-cooled guide rollers.

9. The upper rotary traction mechanism of the film blowing machine according to claim 8, characterized in that: Both ends of the upper swing roller and the lower swing roller are connected with cold air blowers, the cold air blowers are communicated with the inner cavities of the air-cooled guide rollers through air ducts, and the cold air blowers are fixed on the upper swing bracket through blower mounting plates.

10. The upper rotating traction mechanism of the film blowing machine according to claim 1, characterized in that: The radian of the upper half gear and the lower half gear is 35-50°.

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