fishtail propeller

Abstract

This invention relates to a fishtail-type propeller propeller, comprising a base for fixing to a hull, a rotating shaft vertically supported on the base and rotatable relative to the base, and a vertically mounted propeller plate. A laterally extending connecting rod is fixed to the rotating shaft. The invention is characterized by: a limiting seat fixed to the connecting rod, the limiting seat having a vertically extending shaft hole in which a pin is installed; the propeller plate being fixed to the pin and located below the limiting seat; a limiting member also being provided on the pin; and an arc-shaped movable space centered on the pin and a limiting part inserted into the arc-shaped movable space between the limiting member and the limiting seat. The propeller plate rotates relative to the limiting seat within the range defined by the arc-shaped movable space via the pin. This invention allows the propulsion of the hull to come from the combined force of the flexible connection between the water flow and the propeller plate and the rigid connection between the rotating shaft and the propeller plate, which, under the same conditions, helps to increase the forward speed of the hull and is easy to operate.

Description

Technical Field

[0001] This invention relates to the technical field of a propeller, and more particularly to a fishtail propeller. Background Technology

[0002] Currently, propeller propellers are widely used in the shipbuilding industry. They mainly consist of a shaft and blades and are crucial propulsion tools for ships. By manipulating the blades, they generate a reaction force in the water, thus propelling the ship forward. These propeller propellers are typically installed at the stern of the ship. However, traditional manual propeller propellers have relatively low propulsion efficiency. To improve the speed of propeller propellers, researchers have designed a biomimetic fishtail propeller, mimicking the swimming motion of fish, which can control the ship's direction of travel while continuously providing forward propulsion.

[0003] For example, a Chinese invention patent application with patent number CN202210093266.X (publication number CN114275135A) disclosed a "fishtail-type oar mechanism." This fishtail-type oar mechanism includes an oar plate, a handle, a transmission device, and a fixing component. By controlling the handle, the oar plate can be adjusted to swing up and down or left and right. However, the components of this fishtail-type oar mechanism adopt a rigid structure. Under different flow velocities, the propulsion of the boat by the oar plate can only rely on the equivalent output of human power. At the same time, when initially pushing the oar plate, it is relatively difficult to push due to the resistance of the water.

[0004] Therefore, how to provide a propeller that can increase the propulsion speed of a ship while also automatically adapting the propeller blades to the water flow speed is a problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0005] The first technical problem to be solved by the present invention is to provide a fishtail propeller that can increase the forward speed of a ship under the same conditions, in light of the above-mentioned existing technology.

[0006] The second technical problem to be solved by the present invention is to provide a fishtail propeller that enables the propeller to automatically adapt to and adjust the water flow speed, thereby improving the forward speed of the ship under the same conditions.

[0007] The technical solution adopted by the present invention to solve the above-mentioned technical problems is as follows: a fishtail-type propeller propeller, comprising a base for fixing to the hull, a rotating shaft vertically supported on the base and rotatable relative to the base, and a vertically erected propeller plate. A horizontally extending connecting rod is fixed on the rotating shaft. The characteristic feature is that a limiting seat is fixed on the connecting rod, and a vertically extending shaft hole is opened in the limiting seat. A pin shaft rotatable relative to the limiting seat is installed in the shaft hole. The propeller plate is fixed on the pin shaft and located below the limiting seat. At the same time, a limiting member rotatable with the pin shaft is also provided on the pin shaft. An arc-shaped movable space with the pin shaft as the center and a limiting part inserted into the arc-shaped movable space are provided between the limiting member and the limiting seat. The propeller plate rotates relative to the limiting seat within the range defined by the arc-shaped movable space through the pin shaft.

[0008] To better facilitate relative rotation between the limiting component and the limiting seat, preferably, the limiting seat includes a limiting disk, and the limiting component is a limiting piece positioned on the pin. The arc-shaped movable space and the limiting portion are disposed on the limiting disk and the limiting piece. Using the limiting piece and the limiting disk facilitates processing and assembly.

[0009] Preferably, the arc-shaped movable space is located on the limiting plate, and the limiting part is a limiting post designed on the limiting piece, to facilitate processing and fitting. Of course, the arc-shaped movable space can also be designed on the limiting piece, and the limiting post can be designed on the limiting plate; such a solution can also achieve the purpose of the present invention.

[0010] To enable the paddle to automatically adapt to and adjust to the water flow speed, preferably, an arc-shaped limiting opening is cut out on the periphery of the limiting plate. Two spring cavities are designed within the limiting plate, located on either side of the arc-shaped limiting opening. Each spring cavity contains a sliding block. The inner end of the sliding block abuts against the spring located in the corresponding spring cavity, while the outer end of the sliding block protrudes from the corresponding spring cavity and extends into the limiting opening, forming the arc-shaped movement space between the outer ends of the two sliding blocks. In use, the paddle rotates under the propulsion of the water flow, pushing the sliding block on the corresponding side. The sliding block then compresses the spring on the corresponding side. When the restoring force of the spring and the force of the water flow reach equilibrium, the paddle is positioned at a corresponding deflection angle relative to the limiting seat. Therefore, this ingenious and simple structure can achieve the purpose of the paddle adapting to the water flow speed and automatically adjusting.

[0011] In order to achieve good propulsion efficiency of the propeller, preferably, the central angle corresponding to the arc-shaped active space is 90° to 150°.

[0012] To accommodate the shape of the arc-shaped limiting port, preferably, the two spring cavities are designed as arc-shaped cavities with the center of the pin shaft as the center, and the two sliding blocks are also designed as arc-shaped blocks accordingly.

[0013] In order to achieve the blocking of the limiting post, preferably, the arc-shaped movable space can also be designed as an arc-shaped notch on the circumference of the limiting plate, and the two side walls of the arc-shaped notch can respectively block the limiting post;

[0014] Alternatively, the arc-shaped active space can be designed as an arc-shaped elongated hole or arc-shaped elongated groove located on the end face of the limiting plate, and the inner walls of both ends of the arc-shaped elongated hole or arc-shaped elongated groove can respectively abut against the limiting post.

[0015] Alternatively, the limiting disk may have two circumferentially spaced limiting protrusions on its circumferential surface, forming the arc-shaped movable space between the two protrusions, with the limiting post abutting against each of the two protrusions. These solutions are simple in structure and easy to implement.

[0016] To secure the limiting seat to the connecting rod, preferably, the limiting seat further includes a limiting cylinder vertically fixed to the connecting rod, with the limiting disc fixed to the upper part of the limiting cylinder. This structure helps improve the smoothness of the pin's rotation.

[0017] To make the paddle easier to deflect under the action of water flow, it is preferable that the paddle is eccentrically fixed to the pin.

[0018] To enable the shaft to rotate more smoothly and flexibly within the base, the base is preferably designed as a sleeve, and the shaft is supported within the sleeve by a first upper bearing and a first lower bearing.

[0019] To adjust the installation position of the limiting piece on the pin, preferably, the upper end of the pin is provided with n vertically spaced positioning grooves, and the limiting piece is provided with radial threaded holes corresponding to the positioning grooves of the pin. After adjusting the position of the limiting piece vertically, a screw is connected to the threaded hole and then inserted into the positioning groove at the corresponding height on the pin. After tightening the screw, the limiting piece can be fixed.

[0020] Compared to existing technologies, the paddleboard in this invention is rotatably mounted on the connecting rod via a pin, and its rotation angle is limited by the arc-shaped movable space. Therefore, in the initial stage when pushing the rotating shaft and connecting rod to drive the paddleboard in one direction, the paddleboard will rotate at an angle relative to the limiting seat and connecting rod due to the water flow. At this time, the rotation of the paddleboard will propel the hull forward, and pushing the paddleboard is relatively easy and effortless. When the limiting pin is constrained by the arc-shaped movable space, it is equivalent to the connecting rod and the paddleboard becoming rigidly connected. At this time, the rotation of the rotating shaft will drive the paddleboard to start rotating synchronously. Obviously, this invention fully utilizes the propulsive force of the water flow before rigid contact, enabling the hull to start moving forward, and with this assistance, pushing the paddleboard at the beginning is not difficult. Similarly, when driving the paddleboard to rotate in the opposite direction, the same assistance effect and operational feel are achieved. Therefore, this invention enables the hull's forward propulsion to come from the dual force of the flexible connection between the water flow and the paddleboard and the rigid connection between the rotating shaft and the paddleboard. Thus, under the same conditions, it will help increase the hull's forward speed and make operation easier. In particular, the use of two spring-operated sliding blocks to form an arc-shaped moving space allows the paddle to automatically adjust its swing amplitude according to the speed of the water flow, thereby providing greater propulsion to the hull and making the aforementioned effects more pronounced. Attached Figure Description

[0021] Figure 1 This is a three-dimensional structural diagram of the first embodiment of the present invention;

[0022] Figure 2 for Figure 1 A longitudinal sectional view;

[0023] Figure 3 for Figure 2 Schematic diagram of cross section AA (limiting plate and limiting post in initial state);

[0024] Figure 4 This is a three-dimensional structural diagram of the second embodiment of the invention;

[0025] Figure 5 for Figure 4 A longitudinal sectional view;

[0026] Figure 6 for Figure 5 Schematic diagram of cross section BB (limiting plate and limiting post in initial state);

[0027] Figure 7 This is a cross-sectional schematic diagram of the limiting disk and limiting post in the initial state according to the third embodiment of the invention;

[0028] Figure 8 This is a cross-sectional schematic diagram of the limiting disk and limiting post in the initial state in the fourth embodiment of the invention.

[0029] In the diagram: 1. Base; 2. Rotating shaft; 3. Paddle plate; 4. Connecting rod; 5. Limiting seat; 51. Limiting disc; 511. Arc-shaped notch; 512. Arc-shaped limiting port; 513. Spring cavity; 514. Arc-shaped elongated hole; 515. Limiting protrusion; 52. Limiting cylinder; 6. Pin; 7. Limiting piece; 71. Limiting post; 8. Sliding block; 9. Spring; First upper bearing 01; First lower bearing 02; Second upper bearing 03; Second lower bearing 04; Pin 05; Positioning plate 06. Detailed Implementation

[0030] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0031] Example 1:

[0032] like Figures 1-3 In this embodiment, the fishtail propeller can be installed at the stern of the hull to propel the hull forward. It includes a base 1, a rotating shaft 2, a propeller plate 3, a connecting rod 4, a limiting seat 5, and a pin 6. The base 1 is used to fix itself to the hull and to support other components of the fishtail propeller. Therefore, the shape of the base can be varied. However, in order to support the rotation of the rotating shaft 2, in this embodiment, it is preferred that the base 1 be designed as a sleeve.

[0033] The aforementioned rotating shaft 2 is vertically supported within the base 1 and can rotate relative to the base 1. To ensure the flexibility of the rotating shaft 2's rotation, a first upper bearing 01 and a first lower bearing 02 are correspondingly installed at the upper and lower parts within the base 1. The rotating shaft 2 is supported within the base 1 by the first upper bearing 01 and the first lower bearing 02. The vertical orientation of the rotating shaft 2 can be understood as being essentially perpendicular to the horizontal plane; however, it can also be appropriately tilted at a certain angle relative to the horizontal plane when installation is required.

[0034] The connecting rod 4 extends laterally and is fixed to the rotating shaft 2. In the figure, the connecting rod 4 extends horizontally and is perpendicular to and fixed to the rotating shaft 2 so that the connecting rod 4 rotates synchronously with the rotating shaft 2. There are several ways to fix the connecting rod 4 to the rotating shaft 2, such as a conventional keyway connection; or as shown in the figure, the lower end of the rotating shaft 2 is inserted into the shaft hole at the right end of the connecting rod 4 and connected by a radial pin 05.

[0035] The aforementioned limiting seat 5 is fixed to the aforementioned connecting rod 4. The specific position depends on the needs. In the figure, the limiting seat 5 is fixed to the left end of the connecting rod 4. The limiting seat 5 has a vertically extending shaft hole, which is used to install the aforementioned pin 6. The shape of the limiting seat 5 can also be various. Considering the installation of the pin 6, it is designed as follows: It includes a limiting plate 51 and a limiting cylinder 52. The limiting cylinder 52 is vertically fixed to the connecting rod 4, and the limiting plate 51 is fixed to the upper part of the limiting cylinder 52. The shaft hole passes through the center of the limiting plate 51 and the center of the limiting cylinder 52 in the vertical direction. Also considering the flexibility of the pin 6 rotation, a second upper bearing 03 and a second lower bearing 04 are installed in the upper and lower parts of the limiting cylinder 52.

[0036] The aforementioned pin 6 is also supported in the shaft hole of the limiting seat 5 by the second upper bearing 03 and the second lower bearing 04, thus enabling rotation relative to the limiting seat 5. The aforementioned paddle 3 is placed vertically, fixed to the pin 6 and located below the limiting seat 5. In order to make the paddle 3 more easily deflected under the impact of water flow, preferably, the paddle 3 is eccentrically fixed to the pin 6. In the figure, the paddle 3 is provided with an eccentric mounting hole. After the lower end of the pin 6 passes through a positioning plate 06 and is inserted into the mounting hole, the positioning plate 06 is then fixed to the paddle 3 by screws. The positioning plate 06 can restrain the pin 6 to prevent the pin 6 from detaching from the paddle 3.

[0037] To limit the rotation angle of the aforementioned pin 6 and paddle 3 relative to the limiting seat 5, a key improvement in this embodiment is that the pin 6 is also provided with a limiting member that can rotate with the pin 6. This limiting member can be installed on the pin 6 exposed below the limiting seat 5, but preferably, in the figure, the limiting member is installed on the pin 6 exposed above the limiting seat 5. Furthermore, an arc-shaped movable space centered on the pin 6 and a limiting part inserted into this arc-shaped movable space are provided between the limiting member and the limiting seat 5. In this embodiment, the limiting member is designed as a limiting piece 7. Combined with the specific structure of the limiting seat 5, the arc-shaped movable space and the limiting part are set on the limiting plate 51 and the limiting piece 7. Preferably, the arc-shaped movable space is located on the limiting plate 51, and the limiting part is a limiting post 71 designed on the limiting piece 7. This limiting post 71 can be formed by a protrusion on the limiting piece 7 itself, or it can be constructed as a screw installed on the limiting piece 7 as shown in the figure. Thus, when the pin 6 drives the propeller 3 to rotate, it will drive the limiting piece 7 and the limiting post 71 to rotate together. Since the limiting post 71 is restricted by the arc-shaped moving space, the propeller 3 and its pin 6 can only rotate relative to the limiting seat 5 within the range limited by the arc-shaped moving space.

[0038] The arc-shaped movable space on the aforementioned limiting plate 51 can be formed in several ways, such as... Figure 1 and Figure 2In this design, the arc-shaped movable space is an arc-shaped notch 511 located on the circumference of the limiting disk 51, with a central angle of α (see [link to relevant documentation]). Figure 3 The two side walls of the arc-shaped notch 511 can respectively abut against the limiting post 71, which can limit the rotation angle of the limiting post 71.

[0039] Meanwhile, in order to adjust the position of the limiting piece 7 on the pin 6 as needed, in this embodiment, four positioning grooves 61 spaced vertically apart are provided on the upper surface of the pin 6 (see [reference]). Figure 2 The number of positioning holes can be set as needed. The limiting piece 7 is provided with radial threaded holes 72 corresponding to the positioning groove 61 of the pin 6. After adjusting the limiting piece 7 up and down to move it to the required height, use screws (not shown in the figure) to connect it to the threaded holes 72 and then insert it into the positioning groove 61 of the corresponding height on the pin 6 to complete the fixing of the limiting piece 7.

[0040] When using, such as Figure 3 As shown, if the initial state is that the paddle 3 and the connecting rod 4 are in the same horizontal position, when the rotating shaft 2 is pushed by hand or handle (fixed to the upper end of the rotating shaft 2), the rotation of the rotating shaft 2 will drive the connecting rod 4 to rotate, and thus drive the paddle 3 in one direction (e.g., Figure 3 In the initial stage of rotation (clockwise as indicated by the middle arrow), the paddle 3 will rotate relative to the limiting seat 5 and connecting rod 4 by an angle due to the water flow. The maximum angle of rotation occurs when the limiting post 71 touches the lower end of the arc-shaped movable space. Figure 3 As shown by the dotted line, the rotation of paddle 3 propels the boat forward. At this stage, due to the deflection of paddle 3, pushing it is initially easy and effortless. When the limiting post 71 is restrained at the lower end of the arc-shaped movable space, the connecting rod 4 and paddle 3 become rigidly connected. Subsequently, the rotation of the shaft 2 directly drives the paddle 3 to rotate synchronously. Therefore, this embodiment utilizes the propulsive force of the water flow to propel the boat forward. Similarly, when the paddle 3 is rotated in the opposite direction, it provides the same assist effect and operational feel. Thus, the final forward propulsion of the boat comes from the combined force of the flexible connection between the water flow and paddle 3 and the rigid connection between the shaft and paddle 3. Therefore, under the same conditions, the boat's forward speed can be increased, and this embodiment is easier to operate at the same boat speed.

[0041] Example 2: Since the water flow velocity varies in different river channels, and even in different sections of the same river channel, it is desirable that the pre-deflection angle of the paddle plate 3 can automatically adjust according to the water flow velocity in order to fully utilize these different velocities. Therefore, this example makes further improvements, such as... Figures 4 to 6That is, based on the first embodiment described above, two sliding blocks 8 and two springs 9 are added. Specifically, an arc-shaped limiting opening 512 is cut out on the periphery of the limiting disk 51. The shape of the arc-shaped limiting opening 512 is equivalent to the arc-shaped notch 511 described above, but their functions are different. At the same time, two spring cavities 513 are designed inside the limiting disk 51, respectively located on both sides of the arc-shaped limiting opening 512. A sliding block 8 is constrained in each spring cavity 513. The inner end of each sliding block 8 abuts against the spring 9 located in the corresponding spring cavity 513. The outer end of each sliding block 8 is exposed outside the corresponding side spring cavity 513 and extends into the arc-shaped limiting opening 512, forming an arc-shaped movable space between the outer ends of the two sliding blocks 8. At this time, the central angle of the arc-shaped movable space is β. The central angle β is a variable, preferably between 90° and 150°. Furthermore, considering the ease of processing and assembly, the spring cavity 513 in the figure is designed as an arc-shaped groove with the opening facing upwards. A cover plate can also be added to this arc-shaped groove for covering. In addition, for stable force application, the two spring cavities 513 are designed as arc-shaped cavities with equal diameters centered on the center of the pin 6, and the two sliding blocks 8 are also designed as arc-shaped blocks accordingly.

[0042] In this embodiment, the usage process is the same as in the first embodiment described above. However, when encountering rapid water flow, the thrust of the water flow on the paddle 3 increases. At this time, the paddle 3 will drive the limiting post 71 to continue pushing the sliding block 8 on the corresponding side, causing the sliding block 8 to compress the spring 9 on the corresponding side. That is, the compression of the spring 9 on the corresponding side increases, the inward movement of the sliding block 8 also increases, the range of the arc-shaped activity space (i.e., the central angle β) also increases, and the adjustable angle of the paddle 3 also increases. Conversely, when traveling to a river area with gentle water flow, the thrust of the water flow on the paddle 3 is small, the sliding block 8 compresses the spring 9 on the corresponding side, and the force on the spring 9 on the corresponding side is also small. At this time, the compression of the spring 9 on the corresponding side is small, the inward movement of the sliding block 8 is also small, the range of the arc-shaped activity space (i.e., the central angle β) becomes smaller, and the automatic adjustment angle of the paddle 3 is correspondingly smaller. Obviously, the use of two sliding blocks 8 formed by the action of spring 9 to form an arc-shaped moving space allows the paddle 3 to automatically adjust the swing amplitude according to the speed of the water flow, thereby making better use of the water flow and providing greater propulsion for the hull.

[0043] Example 3: Reference Figure 7 The difference between this embodiment and the first embodiment lies in the way the arc-shaped movable space is formed. Specifically, the arc-shaped movable space in this embodiment is designed as an arc-shaped elongated hole 514 or an arc-shaped elongated groove located on the end face of the limiting disk 51. The inner walls of both ends of the arc-shaped elongated hole 514 or the arc-shaped elongated groove can respectively abut against the limiting post 71. The remaining technical features of this embodiment are the same as those of the first embodiment and will not be repeated here.

[0044] Example 4: Reference Figure 8The difference between this embodiment and the first embodiment is the formation method of the arc-shaped movable space. Specifically, two circumferentially spaced limiting protrusions 515 are provided on the circumferential surface of the limiting disk 51, forming an arc-shaped movable space between the two limiting protrusions 515. The limiting post 71 can respectively abut against the two limiting protrusions 515. Similarly, the other technical features of this embodiment are the same as those of the first embodiment, and will not be repeated here.

[0045] In addition to the above embodiments, the arc-shaped movable space can also be set on the limiting piece 7, and the limiting post 71 can be set on the limiting plate 51. Therefore, such a solution also falls within the protection scope of the present invention.

[0046] It should be noted that in the description of this embodiment, the terms "front," "rear," "left," "right," "inner," "outer," "upper," and "lower," etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings. They are merely for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. The terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication between two elements. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

Claims

1. A fishtail propeller propeller, comprising a base (1) for fixing to a hull, a rotating shaft (2) vertically supported on the base (1) and rotatable relative to the base (1), and a vertical propeller blade (3), wherein a laterally extending connecting rod (4) is fixed on the rotating shaft (2), characterized in that: A limiting seat (5) is fixed on the connecting rod (4). A vertically extending shaft hole is opened in the limiting seat (5). A pin (6) that can rotate relative to the limiting seat (5) is installed in the shaft hole. The paddle (3) is fixed on the pin (6) and located below the limiting seat (5). At the same time, a limiting member that can rotate with the pin (6) is also provided on the pin (6). An arc-shaped movable space with the pin (6) as the center and a limiting part inserted into the arc-shaped movable space are provided between the limiting member and the limiting seat (5). The paddle (3) rotates relative to the limiting seat (5) within the range defined by the arc-shaped movable space through the pin (6). The limiting seat (5) includes a limiting plate (51). The limiting member is a limiting piece (7) positioned on the pin. The arc-shaped movable space and the limiting part are provided on the limiting plate (51) and the limiting piece (7).

2. The fishtail propeller according to claim 1, characterized in that: The arc-shaped active space is located on the limiting plate (51), and the limiting part is a limiting post (71) designed on the limiting piece (7).

3. The fishtail-type propeller propeller according to claim 2, characterized in that: An arc-shaped limiting opening (512) is cut out on the periphery of the limiting plate (51). At the same time, two spring cavities (513) are designed in the limiting plate (51), which are located on both sides of the arc-shaped limiting opening (512). A sliding block (8) is constrained in each spring cavity (513). The inner end of each sliding block (8) abuts against the spring (9) located in the corresponding spring cavity (513). The outer end of the sliding block (8) is exposed in the corresponding spring cavity (513) and extends into the arc-shaped limiting opening (512). An arc-shaped movable space is formed between the outer ends of the two sliding blocks (8).

4. The fishtail propeller according to claim 3, characterized in that: The central angle corresponding to the arc-shaped activity space is 90°~150°.

5. The fishtail-type propeller propeller according to claim 3, characterized in that: The two spring cavities (513) are designed as equal-diameter arc cavities with the center of the pin (6) as the center, and the two sliding blocks (8) are also designed as arc blocks accordingly.

6. The fishtail propeller according to claim 2, characterized in that: The arc-shaped active space is designed as an arc-shaped notch (511) on the circumference of the limiting plate (51), and the two side walls of the arc-shaped notch (511) can respectively abut against the limiting post (71); Alternatively, the arc-shaped active space is designed as an arc-shaped long hole (514) or an arc-shaped long groove on the end face of the limiting plate (51), and the inner walls of the two ends of the arc-shaped long hole (514) or the arc-shaped long groove can respectively abut against the limiting post (71). Alternatively, the circumferential surface of the limiting disk (51) is provided with two circumferentially spaced limiting protrusions (515), and the arc-shaped movable space is formed between the two limiting protrusions (515). The limiting post (71) can respectively resist the two limiting protrusions (515).

7. The fishtail propeller according to claim 1, characterized in that: The limiting seat (5) also includes a limiting cylinder (52) vertically fixed to the connecting rod (4), and the limiting plate (51) is fixed to the upper part of the limiting cylinder (52).

8. The fishtail propeller according to any one of claims 1 to 7, characterized in that: The paddle (3) is eccentrically fixed to the pin (6).

9. The fishtail propeller according to any one of claims 1 to 7, characterized in that: The base (1) is designed as a sleeve, and the rotating shaft (2) is supported in the sleeve by the first upper bearing (01) and the first lower bearing (02).

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