Feeding device for pseudo-boehmite crushing

Abstract

The invention relates to the technical field of pseudo-boehmite processing, in particular to a pseudo-boehmite crushing feeding device which comprises a conveying cylinder, a feeding hopper is rotationally connected to the left portion of the outer side of the conveying cylinder, a discharging port is formed in the right portion of the outer side of the conveying cylinder, and a first driving motor is arranged at the left end of the conveying cylinder; an output shaft of the first driving motor penetrates through the conveying cylinder and is fixedly provided with a propeller, a base is arranged at the bottom end of the conveying cylinder, a first guide frame and a second guide frame are fixedly installed at the upper end of the base, the feeding device comprises an environment adaptation mechanism and a pretreatment mechanism, and the environment adaptation mechanism further comprises a position adjusting module and a buffering protection module. The sliding block slides in the sliding rail, the horizontal distance difference caused by angle change of the conveying barrel is made up, the vertical angle of the conveying barrel can be adjusted under the condition that the horizontal position of the first electric rod and the horizontal position of the second electric rod are not changed, and therefore the conveying barrel can be conveyed upwards and downwards, and the conveying barrel can adapt to various complex environments conveniently.

Description

Technical Field

[0001] The invention relates to the technical field of pseudo-boehmite processing, in particular to a feeding device for crushing pseudo-boehmite. Background Art

[0002] Pseudoboehmite can be used as a raw material for the production of catalyst carriers, activated alumina and other aluminum salts. It is widely used as catalyst carriers, catalysts and adsorbents, coating additives, high-end ceramics, high-efficiency catalysts in petrochemicals, submicron / nano-level grinding and polishing materials, cosmetic fillers and inorganic membrane materials, etc. It is a new type of material with broad development prospects.

[0003] Pseudo-boehmite faces a more complex transportation scenario, which requires both upward and downward transportation. The existing feeding device for pseudo-boehmite crushing is difficult to adapt to the complex transportation environment, and the feeding effect is poor. In addition, the pseudo-boehmite stones after mining are mostly relatively large. Without prior processing, it is not only inconvenient to transport, but also difficult to enter some fine crushing devices.

[0004] Therefore, a feeding device for crushing pseudo-boehmite is proposed. Summary of the Invention

[0005] The object of the present invention is to provide a feeding device for crushing pseudo-boehmite to solve the problems of poor environmental adaptability and inconvenience in conveying larger stones raised in the above-mentioned background technology.

[0006] To achieve the above-mentioned purpose, the present invention provides the following technical solutions: a feeding device for crushing pseudo-boehmite, comprising a conveying drum, a feed hopper being rotatably connected to the left outer side of the conveying drum, a discharge port being provided at the right outer side of the conveying drum, a first driving motor being provided at the left end of the conveying drum, an output shaft of the first driving motor passing through the conveying drum and fixedly mounted with a propeller, a base being provided at the bottom end of the conveying drum, a first guide frame and a second guide frame being fixedly mounted at the upper end of the base, the feeding device comprising an environmental adaptation mechanism and a pretreatment mechanism, the environmental adaptation mechanism further comprising a position adjustment module and a buffer protection module, the position adjustment module being used to adjust the height of the feed and discharge ports so that the conveying drum can be transported both to a high place and to a low place, and the buffer protection module being used to provide a reaction force, which can provide a buffering effect for the movement of the conveying drum without interfering with the position adjustment of the conveying drum;

[0007] The pretreatment mechanism also includes a crushing module and a cutting module. The crushing module is used to cut large pieces of diaspore into small pieces so that the diaspore can enter the conveying cylinder. The cutting module is used to split the large pieces of diaspore.

[0008] Preferably, the position adjustment module includes a slide rail fixedly mounted at the middle of the bottom end of the conveying cylinder, the interior of the slide rail is slidably connected to a slider, the slider is hinged to a first support, and the bottom end of the first support is fixedly mounted with a first electric rod.

[0009] Preferably, a second support is hinged on the left side of the bottom end of the conveying cylinder, a second electric rod is fixedly installed on the bottom end of the second support, and a guide cylinder is hinged on the outer side of the discharge port.

[0010] Preferably, the first support is slidably connected in the second guide frame, and the second support is slidably connected to the front end of the first guide frame.

[0011] Preferably, the buffer protection module includes a first telescopic airbag arranged on the left side of the slider, the first telescopic airbag is fixedly connected to one end of the air pipe, the other end of the air pipe passes through the slider and is fixedly connected to the second telescopic airbag, and the second telescopic airbag is arranged on the right side of the slider.

[0012] Preferably, a first return spring is provided in the first telescopic airbag, and a second return spring is provided in the second telescopic airbag.

[0013] Preferably, the crushing module includes a bracket fixedly mounted on the front end of the second support, a second drive motor is provided at the bottom end of the bracket, the output shaft of the second drive motor passes through the bracket and is fixedly connected to a rotating rod, the other end of the rotating rod is inserted into the feed hopper, and paddles are evenly provided on the outside of this end of the rotating rod, a first notch is opened on the paddle, and a first blade is evenly provided on the inner wall of the feed hopper.

[0014] Preferably, both sides and the front end of the first blade are provided with cutting edges, and the first notch is adapted to the first blade.

[0015] Preferably, the cutting module includes a gear ring arranged on the inner wall of the feed hopper, the gear ring is engaged with several groups of gears, the gears are fixedly connected to one end of the second rotating rod, the other end of the second rotating rod is rotatably connected to the paddle, and several groups of second blades are arranged on the outside of the second rotating rod.

[0016] Preferably, the second blade is arranged in a diamond shape, and a second notch for the movement of the second blade is opened at the upper end of the blade.

[0017] Beneficial effects of the present invention:

[0018] 1. The present invention utilizes a position adjustment module to facilitate the use of a slider to slide within a slide rail, thereby compensating for the horizontal distance difference caused by the angle change of the conveying cylinder. This allows the first and second electric rods to adjust the vertical angle of the conveying cylinder while maintaining their horizontal positions. This allows the conveying cylinder to be transported both upward and downward to different positions, making it easier for the conveying cylinder to adapt to various complex environments.

[0019] 2. The present invention, by designing a buffer protection module in conjunction with a position adjustment module, is advantageous in that when the first electric rod fails and loses its supporting function, double buffering is performed by the first telescopic airbag and the first return spring, thereby reducing the descending speed of the right end of the conveying cylinder. This can not only effectively prevent the conveying cylinder from being damaged by impact due to falling, but also ensure that nearby personnel are protected from injury, thereby significantly improving the safety of the entire device.

[0020] 3. The present invention is advantageous in carrying out preliminary crushing treatment on the stone materials entering the feed hopper by designing a crushing module, making it easier for the stone materials to enter the conveying cylinder, and a first notch is provided on the paddle. The smaller first notch allows the first blade to pass through, thereby ensuring the rotation effect of the paddle, without affecting the paddle's pushing of the stone materials for crushing.

[0021] 4. The present invention is designed to cooperate with the cutting module to realize the vertical rotation of the second blade by utilizing the horizontal rotation force of the blade, thereby facilitating the second blade to vertically cut the stone and further improving the crushing effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only for the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0023] Figure 1 This is an overall three-dimensional schematic diagram of a feeding device for crushing pseudo-boehmite according to an embodiment of the present invention;

[0024] Figure 2 A feeding device for pseudo-boehmite crushing according to an embodiment of the present invention Figure 1 Schematic diagram of the cross section at AA in the middle;

[0025] Figure 3 A feeding device for pseudo-boehmite crushing according to an embodiment of the present invention Figure 2 The enlarged schematic diagram of point C in the middle;

[0026] Figure 4 A feeding device for pseudo-boehmite crushing according to an embodiment of the present invention Figure 1 Schematic diagram of the cross section at the middle BB;

[0027] Figure 5 A feeding device for pseudo-boehmite crushing according to an embodiment of the present invention Figure 4 The enlarged schematic diagram of point D in the middle;

[0028] Figure 6 This is a schematic diagram of an explosion of an environmental adaptation mechanism of a feeding device for pseudo-boehmite crushing according to an embodiment of the present invention;

[0029] Figure 7 This is a three-dimensional schematic diagram of a feed hopper of a feeding device for crushing pseudo-boehmite according to an embodiment of the present invention;

[0030] Figure 8 This is a three-dimensional schematic diagram of a pretreatment mechanism of a feeding device for crushing pseudo-boehmite according to an embodiment of the present invention.

[0031] The markings in the figure are: 1. Conveying cylinder; 2. Feed hopper; 3. Discharge port; 4. First drive motor; 5. Propeller; 6. Base; 7. First guide frame; 8. Second guide frame; 9. Slide rail; 10. Slider; 11. First support; 12. First electric rod; 13. Second support; 14. Second electric rod; 15. Guide cylinder; 16. First telescopic airbag; 17. Air pipe; 18. Second telescopic airbag; 19. First return spring; 20. Second return spring; 21. Bracket; 22. Second drive motor; 23. Rotating rod; 24. Paddle; 25. First notch; 26. First blade; 27. Gear ring; 28. Gear; 29. ​​Second rotating rod; 30. Second blade; 31. Second notch. DETAILED DESCRIPTION

[0032] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to specific embodiments.

[0033] It should be noted that, unless otherwise defined, the technical or scientific terms used in the present invention should have the usual meanings understood by people with ordinary skills in the field to which the present invention belongs. The "first", "second" and similar words used in the present invention do not indicate any order, quantity or importance, but are only used to distinguish different components. "Include" or "comprise" and similar words mean that the elements or objects appearing before the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects. "Connect" or "connected" and similar words are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to indicate relative position relationships. When the absolute position of the object being described changes, the relative position relationship may also change accordingly.

[0034] See also Figures 1 to 8The present invention provides a technical solution: a feeding device for pseudo-boehmite crushing, comprising a conveying drum 1, a feed hopper 2 being rotatably connected to the outer left portion of the conveying drum 1, a discharge port 3 being provided at the outer right portion of the conveying drum 1, a first driving motor 4 being provided at the left end of the conveying drum 1, an output shaft of the first driving motor 4 passing through the conveying drum 1 and fixedly mounted with a propeller 5, a base 6 being provided at the bottom end of the conveying drum 1, a first guide frame 7 and a second guide frame 8 being fixedly mounted at the upper end of the base 6, the feeding device comprising an environmental adaptation mechanism and a pretreatment mechanism, the environmental adaptation mechanism further comprising a position adjustment module and a buffer protection module, the position adjustment module being used to adjust the height of the feed and discharge ports so that the conveying drum 1 can be transported both to a high place and to a low place, the buffer protection module being used to provide a reaction force, which can provide a buffering effect for the movement of the conveying drum 1 without interfering with the position adjustment of the conveying drum 1;

[0035] The pretreatment mechanism further comprises a crushing module and a cutting module. The crushing module is used to chop large pieces of diaspore into small pieces so that the diaspore can enter the conveying cylinder 1 , and the cutting module is used to split the large pieces of diaspore.

[0036] As an embodiment of the present invention, Figure 1 and Figure 6 As shown, the position adjustment module includes a slide rail 9 fixedly installed in the middle of the bottom end of the conveying cylinder 1, and a slider 10 is slidably connected inside the slide rail 9. The slider 10 is hinged with a first support 11, and a first electric rod 12 is fixedly installed at the bottom end of the first support 11. A second support 13 is hinged at the left bottom end of the conveying cylinder 1, and a second electric rod 14 is fixedly installed at the bottom end of the second support 13. A guide cylinder 15 is hinged on the outside of the discharge port 3. The first support 11 is slidably connected to the second guide frame 8, and the second support 13 is slidably connected to the front end of the first guide frame 7. When the conveying cylinder 1 transports diaspore to a higher place, the first electric rod 12 is started, and the first electric rod 12 drives the first support 11 to move upward along the second guide frame 8. Then, because the first support 11 is hinged with the slider 10, the first support 11 is slidably connected to the slide rail 9 at the bottom end of the conveying cylinder 1, so the conveying cylinder 1 The right end is lifted upward, and the guide cylinder 15 hinged on the discharge port 3 adjusts the discharge angle of the discharge port 3 under the action of gravity. When the conveying cylinder 1 needs to transport diaspore to a lower place, the second electric rod 14 is started, and the second electric rod 14 drives the left end of the conveying cylinder 1 to move upward through the second support 13. Because the slider 10 and the slide rail 9 are slidingly connected, the second support 13 is hinged to the conveying cylinder 1, and the first support 11 is hinged to the slider 10, so the second support 13 can move upward along the first guide frame 7, which is conducive to using the slider 10 to slide in the slide rail 9 to make up for the horizontal distance difference caused by the angle change of the conveying cylinder 1, so that the first electric rod 12 and the second electric rod 14 can adjust the vertical angle of the conveying cylinder 1 without changing the horizontal position, so that the conveying cylinder 1 can be transported both upward and downward, which makes it easy for the conveying cylinder 1 to adapt to various complex environments.

[0037] As an embodiment of the present invention, Figure 2 and Figure 3 as well as Figure 6 As shown, the buffer protection module includes a first telescopic airbag 16 arranged on the left side of the slider 10, the first telescopic airbag 16 is fixedly connected to one end of the air delivery pipe 17, the other end of the air delivery pipe 17 passes through the slider 10 and is fixedly connected to the second telescopic airbag 18, the second telescopic airbag 18 is arranged on the right side of the slider 10, a first return spring 19 is arranged in the first telescopic airbag 16, and a second return spring 20 is arranged in the second telescopic airbag 18. When the conveying cylinder 1 is conveying upward, if the first electric rod 12 fails and loses its supporting function, the left end of the conveying cylinder 1 is restricted by the second support 13 and can only rotate. Therefore, only when the slider 10 slides in the slide rail 9 can the first support 11 be lowered along the second guide frame 8, and then the first return spring 20 is reset. The spring 19 provides a gradually increasing reaction force for the slider 10, causing the slider 10 to move slowly to the left in the slide rail 9, and the slider 10 will also squeeze the first telescopic airbag 16. The gas in the first telescopic airbag 16 can only slowly enter the second telescopic airbag 18 through the smaller air pipe 17, so that the speed of the slide rail 9 moving to the left is further slowed down, that is, the speed of the right end of the conveying cylinder 1 descending is slowed down, which is beneficial when the first electric rod 12 fails and loses its supporting function. Double buffering is performed by the first telescopic airbag 16 and the first return spring 19, reducing the speed of the right end of the conveying cylinder 1 descending. It can not only effectively prevent the conveying cylinder 1 from being damaged by impact due to falling, but also ensure that the staff nearby are protected from injury, thereby significantly improving the safety of the overall device.

[0038] As an embodiment of the present invention, Figure 5 and Figure 7 as well as Figure 8As shown, the crushing module includes a bracket 21 fixedly mounted on the front end of the second support 13, a second drive motor 22 is provided at the bottom end of the bracket 21, the output shaft of the second drive motor 22 passes through the bracket 21 and is fixedly connected to a rotating rod 23, the other end of the rotating rod 23 is inserted into the feed hopper 2, and blades 24 are evenly provided on the outer side of this end of the rotating rod 23, a first notch 25 is provided on the paddle 24, and a first blade 26 is evenly provided on the inner wall of the feed hopper 2, and cutting edges are provided on both sides and the front end of the first blade 26. The first notch 25 is adapted to the first blade 26. When the stone is poured into the feed hopper 2, the feed hopper 2 is started. The second drive motor 22 drives the paddle 24 to rotate through the rotating rod 23. The paddle 24 drives the stones in the feed hopper 2 to hit the first blade 26, so that the larger stones are broken into smaller stones. Then the first blade 26 can pass through the paddle 24 through the first notch 25, which is conducive to the preliminary crushing of the stones entering the feed hopper 2, making it easier for the stones to enter the conveying cylinder 1, and a first notch 25 is provided on the paddle 24. The smaller first notch 25 can allow the first blade 26 to pass through, ensuring the rotation effect of the paddle 24, without affecting the paddle 24 pushing the stones to be crushed.

[0039] As an embodiment of the present invention, Figure 4 and Figure 5 as well as Figure 8 As shown, the cutting module includes a gear ring 27 arranged on the inner wall of the feed hopper 2, and the gear ring 27 is meshed with several groups of gears 28. The gear 28 is fixedly connected to one end of a second rotating rod 29, and the other end of the second rotating rod 29 is rotatably connected to the paddle 24. Several groups of second blades 30 are arranged on the outer side of the second rotating rod 29. The second blades 30 are arranged in a diamond shape, and a second notch 31 for the movement of the second blades 30 is opened at the upper end of the paddle 24. In the process of the rotating rod 23 driving the paddle 24 to rotate, because the gear ring 27 on the inner wall of the conveying cylinder 1 is meshed with the gear 28, the gear 28 is restricted by the gear ring 27 and rolls along the gear ring 27. The gear 28 drives the second blade 30 to rotate through the second rotating rod 29. Then, because the notch for the rotation of the second blade 30 is opened at the upper end of the paddle 24, the second blade 30 crushes the stone in the feed hopper 2, which is conducive to utilizing the horizontal rotation force of the paddle 24 to drive the second blade 30 to rotate vertically, so that the second blade 30 can vertically cut the stone, further improving the crushing effect.

[0040] Working principle: When the conveying drum 1 conveys diaspore to a higher place, the first electric rod 12 is started, and the first electric rod 12 drives the first support 11 to move upward along the second guide frame 8. Then, because the first support 11 is hinged with the slider 10, the first support 11 is slidably connected to the slide rail 9 at the bottom end of the conveying drum 1, so the right end of the conveying drum 1 is lifted upward, and the guide drum 15 hinged on the discharge port 3 adjusts the discharge angle of the discharge port 3 under the action of gravity. When the conveying drum 1 needs to convey diaspore to a lower place, the second electric rod 14 is started, and the second electric rod 14 drives the left end of the conveying drum 1 to move upward through the second support 13. Because the slider 10 is slidably connected to the slide rail 9, the second support 13 is hinged to the conveying drum 1, and the first support 11 is hinged to the slider 10, so the second support 13 can move upward along the first guide frame 7;

[0041] When the conveying cylinder 1 is conveying upwards, if the first electric rod 12 fails and loses its supporting function, the left end of the conveying cylinder 1 is restricted by the second support 13 and can only rotate. Therefore, only when the slider 10 slides in the slide rail 9 can the first support 11 descend along the second guide frame 8. Then the first return spring 19 provides a gradually increasing reaction force for the slider 10, causing the slider 10 to slowly move to the left in the slide rail 9. The slider 10 also squeezes the first telescopic airbag 16. The gas in the first telescopic airbag 16 can only slowly enter the second telescopic airbag 18 through the smaller air supply pipe 17, further slowing down the speed of the slide rail 9 to the left, that is, the speed of descent of the right end of the conveying cylinder 1.

[0042] When stones are poured into the feed hopper 2, the second drive motor 22 is started, and the second drive motor 22 drives the paddle 24 to rotate through the rotating rod 23. The paddle 24 drives the stones in the feed hopper 2 to hit the first blade 26, so that the larger stones are broken into smaller stones. Then, the first blade 26 can pass through the paddle 24 through the first notch 25;

[0043] In the process of the rotating rod 23 driving the paddle 24 to rotate, because the gear ring 27 on the inner wall of the conveying cylinder 1 is engaged with the gear 28, the gear 28 is restricted by the gear ring 27 and rolls along the gear ring 27. The gear 28 drives the second blade 30 to rotate through the second rotating rod 29. Then, because a notch is provided at the upper end of the paddle 24 for the second blade 30 to rotate, the second blade 30 crushes the stone in the feed hopper 2.

[0044] Those skilled in the art should understand that the discussion of any of the above embodiments is merely illustrative and is not intended to imply that the scope of the present invention (including the claims) is limited to these examples. Within the scope of the present invention, the technical features in the above embodiments or different embodiments may be combined, the steps may be implemented in any order, and there are many other variations of the different aspects of the present invention as described above, which are not provided in detail for the sake of simplicity.

[0045] The present invention is intended to cover all such substitutions, modifications and variations that fall within the broad scope of the appended claims. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A feeding device for crushing pseudo-boehmite, comprising a conveying cylinder (1), the outer left portion of the conveying cylinder (1) is rotatably connected to a feed hopper (2), the outer right portion of the conveying cylinder (1) is provided with a discharge port (3), the left end of the conveying cylinder (1) is provided with a first drive motor (4), the output shaft of the first drive motor (4) passes through the conveying cylinder (1) and is fixedly installed with a propeller (5), the bottom end of the conveying cylinder (1) is provided with a base (6), the upper end of the base (6) is fixedly installed with a first guide frame (7) and a second guide frame (8), characterized in that: The feeding device comprises an environmental adaptation mechanism and a pretreatment mechanism, and the environmental adaptation mechanism further comprises a position adjustment module and a buffer protection module, the position adjustment module is used to adjust the height of the feed and discharge ports so that the conveying cylinder (1) can be conveyed both to a high place and to a low place, and the buffer protection module is used to provide a reaction force, which can provide a buffering effect for the movement of the conveying cylinder (1) without interfering with the position adjustment of the conveying cylinder (1); The pretreatment mechanism also includes a crushing module and a cutting module. The crushing module is used to crush large pieces of diaspore into small pieces so that the diaspore can enter the conveying cylinder (1), and the cutting module is used to split the large pieces of diaspore.

2. A feeding device for crushing pseudo-boehmite according to claim 1, characterized in that: The position adjustment module comprises a slide rail (9) fixedly mounted at the middle of the bottom end of the conveying cylinder (1); a slider (10) is slidably connected inside the slide rail (9); the slider (10) is hingedly connected to a first support (11); and a first electric rod (12) is fixedly mounted at the bottom end of the first support (11).

3. A feeding device for crushing pseudo-boehmite according to claim 2, characterized in that: A second support (13) is hingedly connected to the left portion of the bottom end of the conveying cylinder (1), a second electric rod (14) is fixedly mounted on the bottom end of the second support (13), and a guide cylinder (15) is hingedly connected to the outer side of the discharge port (3).

4. A feeding device for crushing pseudo-boehmite according to claim 3, characterized in that: The first support (11) is slidably connected in the second guide frame (8), and the second support (13) is slidably connected to the front end of the first guide frame (7).

5. A feeding device for crushing pseudo-boehmite according to claim 2, characterized in that: The buffer protection module comprises a first telescopic airbag (16) arranged on the left side of the slider (10), the first telescopic airbag (16) being fixedly connected to one end of an air supply pipe (17), the other end of the air supply pipe (17) passing through the slider (10) and being fixedly connected to a second telescopic airbag (18), the second telescopic airbag (18) being arranged on the right side of the slider (10).

6. A feeding device for crushing pseudo-boehmite according to claim 5, characterized in that: A first return spring (19) is arranged in the first telescopic airbag (16), and a second return spring (20) is arranged in the second telescopic airbag (18).

7. A feeding device for crushing pseudo-boehmite according to claim 3, characterized in that: The crushing module comprises a bracket (21) fixedly mounted on the front end of the second support (13); a second drive motor (22) is arranged at the bottom end of the bracket (21); an output shaft of the second drive motor (22) passes through the bracket (21) and is fixedly connected to a rotating rod (23); the other end of the rotating rod (23) is inserted into the feed hopper (2); blades (24) are evenly arranged on the outer side of the end of the rotating rod (23); a first notch (25) is opened on the blade (24); and a first blade (26) is evenly arranged on the inner wall of the feed hopper (2).

8. A feeding device for crushing pseudo-boehmite according to claim 7, characterized in that: Both sides and the front end of the first blade (26) are provided with cutting edges, and the first notch (25) is adapted to the first blade (26).

9. A feeding device for crushing pseudo-boehmite according to claim 7, characterized in that: The cutting module comprises a toothed ring (27) arranged on the inner wall of the feed hopper (2), the toothed ring (27) being meshed with a plurality of groups of gears (28), the gears (28) being fixedly connected to one end of a second rotating rod (29), the other end of the second rotating rod (29) being rotatably connected to the paddle (24), and a plurality of groups of second blades (30) being arranged on the outer side of the second rotating rod (29).

10. A feeding device for crushing pseudo-boehmite according to claim 9, characterized in that: The second blade (30) is arranged in a rhombus shape, and a second notch (31) for the second blade (30) to move is provided at the upper end of the paddle (24).

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