A rotating crab cage device

Abstract

This invention discloses a rotating crab trap device, aiming to provide a device that can effectively utilize ocean currents to diffuse bait odors, thereby leveraging the crabs' tendency to swim upstream to find odor sources, thus improving the trapping effect. It includes: a base; a crab trap, rotatably mounted on the base via a central shaft; a bait unit disposed in the center of the crab trap; a guide plate disposed at the top of the crab trap; and two side guide channels, one located on the upstream side of the crab trap and the other on the downstream side. One end of each side guide channel connects to the side of the crab trap, forming a guide opening on the side of the trap, while the other end extends towards the center of the crab trap and faces the bait unit. The opening area of ​​the side guide channel gradually decreases from one end to the other.

Description

Technical Field

[0001] This invention relates to a crab trap, specifically a rotating crab trap device. Background Technology

[0002] A crab trap is a fishing gear used to catch crabs (such as swimming crabs and Japanese crabs). Numerous studies have shown that crabs typically rely on current-following behavior to swim upstream in search of scent sources. For example, over 75% of Japanese crabs approach the trap against the current. Therefore, current crab traps generally contain a bait basket filled with fresh bait. After the trap is deployed to the seabed, the fresh bait in the bait basket attracts the prey with the help of the scent diffused by the ocean current. Currently, crab traps are generally stationary, and the bait basket is usually placed haphazardly at the bottom. While this does attract prey with the scent diffused by the ocean current, it doesn't fully utilize the ocean current; the effect of relying on the scent diffused by the current is poor, failing to effectively leverage the crabs' upstream-following behavior in search of scent sources. Summary of the Invention

[0003] The purpose of this invention is to provide a rotating crab trap device that can effectively utilize ocean currents to diffuse bait scents, thereby taking advantage of crabs' tendency to swim upstream to find scent sources, thus improving the trapping effect.

[0004] The technical solution of this invention is:

[0005] A rotating crab trap device, comprising:

[0006] Base;

[0007] Crab cage, which is rotatably mounted on a base via a central shaft;

[0008] The bait unit is located in the middle of the crab trap;

[0009] A flow deflector is installed at the top of the crab cage;

[0010] Two side guide channels are provided, one located on the upstream side of the crab trap and the other on the downstream side. One end of each side guide channel connects to the side of the crab trap, forming a guide opening on the side. The other end of each side guide channel extends towards the center of the crab trap and faces the bait unit. The opening area of ​​the side guide channel gradually decreases from one end to the other. In this rotating crab trap device, after being deployed to the seabed, the crab trap is supported by a base. Because the crab trap is rotatably mounted on the base via a central shaft, and a guide plate is provided on the top of the crab trap, the crab trap will rotate around the central shaft under the action of the ocean current and the guide plate. This ensures that one side of the crab trap faces the ocean current and the other side faces away from it, thus placing one side guide channel on the upstream side and the other side on the downstream side. In this way, the ocean current enters the crab trap through the guide channel on the upstream side, and after flowing past the bait unit, it flows out through the guide channel on the other side. Based on this, on the one hand, the flow resistance of the ocean current entering and leaving the crab trap can be reduced by the guide channel, and on the other hand, the guide channel on the upstream side can guide, converge and accelerate the ocean current, maximizing the diffusion of the bait's scent with the current. This effectively utilizes the ocean current to diffuse the bait's scent, and takes advantage of the crabs' tendency to follow the current and go upstream to find the scent source, thereby improving the trapping effect.

[0011] Preferably, the inner guide channel has one end of the guide plate close to the center of the top of the crab cage, and the other end of the guide plate extends to the top edge of the crab cage or to the outside of the top edge of the crab cage. The inner guide channel is set inside the crab cage and located between the two side guide channels. The bait unit is located inside the inner guide channel. One end of the inner guide channel faces the front of the crab cage and the other end faces the back of the crab cage. The opening area of ​​the inner guide channel gradually decreases from the front of the crab cage to the back of the crab cage. When the ocean current enters the crab trap through the guide channel on the upstream side, it diffuses within the trap. Only a portion flows out through the other guide channel, while the rest flows out through the mesh of the trap's sidewall. However, the portion of the current flowing through the mesh of the trap's sidewall experiences greater flow resistance, hindering the downstream diffusion of the bait's aroma. To address this issue, this solution first improves the guide plate by placing one end close to the center of the crab trap's top and extending the other end to either the top edge or the outer side of the top edge. In this way, the interaction between the ocean current and the guide plate ensures that one side of the crab trap always faces the ocean current, thus ensuring that one side guide channel always faces the upstream side of the trap, while the other side guide channel remains on the downstream side. Based on this, an inner guide channel is arranged between the two side guide channels, and the bait unit is located in the inner guide channel. One end of the inner guide channel faces the upstream side of the crab trap, and the other end faces the downstream side of the crab trap. The opening area of ​​the inner guide channel gradually decreases from the upstream side of the crab trap to the downstream side. In this way, when the ocean current enters the crab trap through the guide channel on the upstream side, it will be guided and accelerated by the inner guide channel, and then flow out through the guide channel on the downstream side. This effectively reduces the diffusion of the ocean current in the crab trap, reduces flow resistance, and further improves the downstream diffusion effect of the bait scent, thereby further improving the trapping effect.

[0012] Preferably, the distance between the inner guide channel and the side guide channel located on the back side of the crab trap is greater than a set value L1, and the distance between the inner guide channel and the side guide channel located on the front side of the crab trap is greater than a set value L2. This prevents crabs captured in the crab trap from climbing through the inner cavity of the inner guide channel into the side guide channel on the back side of the crab trap and escaping; simultaneously, it also prevents crabs captured in the crab trap from climbing through the inner cavity of the inner guide channel into the side guide channel on the front side of the crab trap and escaping.

[0013] Preferably, the guide plates are multiple pieces, with a guide slope between adjacent guide plates. The guide slope is close to the top edge of the crab trap, with its lower edge close to or abutting the top surface of the crab trap, and its upper edge extending obliquely upwards outwards from the crab trap. In this way, the sea current at the top of the crab trap, after flowing along the guide plates to the edge of the top surface of the crab trap, will be guided obliquely upwards through the guide slope, thereby also guiding some of the sea current flowing out through the side guide channel on the back side of the crab trap upwards. As is well known, the flow resistance is high near the seabed and low upwards away from the seabed, thus further improving the downstream diffusion effect of the bait's aroma.

[0014] Preferably, the system also includes a buoyancy component located above the crab trap. The top surface of the crab trap has a top passage hole in the center. The bait unit includes a corrugated telescopic sleeve closed at both ends. A spirally extending helical spring is embedded in the inner wall of the corrugated telescopic sleeve. Several through holes are provided on the side walls of the corrugated telescopic sleeve. The lower end of the corrugated telescopic sleeve is connected to the inside of the crab trap, and the upper end of the corrugated telescopic sleeve is connected to the buoyancy component via a connecting rope that passes through the top passage hole. Currently, the bait in the bait basket is generally piled up, which is not conducive to the release of the bait's aroma. To address this issue, this solution improves the bait unit, creating a breathing-like effect that effectively releases the bait's odor. Specifically, during ocean currents, the buoyancy component pulls the upper end of the corrugated telescopic sleeve upwards, stretching the helical spring and the sleeve. This increases the inner cavity of the sleeve, allowing seawater to pass through and enter via the openings in the sidewall. When the current stops or weakens, the helical spring overcomes the buoyancy of the buoyancy component and the force of the current, causing the sleeve to contract. This reduces the inner cavity, allowing seawater to flow out through the openings in the sidewall. This stretching and contraction of the sleeve creates a breathing-like effect, causing the bait inside to tumble and effectively release its odor.

[0015] Preferably, at least one of the upper and lower ends of the corrugated telescopic sleeve is provided with a removable end cap. This facilitates the addition of bait into the corrugated telescopic sleeve.

[0016] Preferably, the bottom of the crab trap is equipped with several support rollers arranged circumferentially around a central axis. The support rollers are located near the bottom edge of the crab trap and rest on the upper surface of the base. This ensures that the crab trap can be stably supported on the base and can rotate stably around the central axis.

[0017] Preferably, the guide vanes are multiple pieces, all parallel to each other. This improves the guiding effect of the guide vanes in conjunction with the ocean current, so that one side guide channel of the crab trap is located on the upstream side of the crab trap, and the other side guide channel is located on the downstream side of the crab trap.

[0018] Preferably, the crab trap includes a top frame, a bottom frame, and side connecting rods that connect the top frame and the bottom frame. This ensures the stability of the crab trap's structure.

[0019] Preferably, the crab trap is cylindrical, with a steel or concrete base. The cylindrical shape minimizes the trap's impact on the guiding effect of the deflector. A steel or concrete base facilitates its fabrication.

[0020] The beneficial effects of this invention are: on the one hand, the flow resistance of the ocean current entering and exiting the crab trap can be reduced by the flow channel; on the other hand, the flow channel on the upstream side can guide, converge and accelerate the ocean current, so as to maximize the diffusion of the bait's scent with the current, thereby effectively utilizing the ocean current to diffuse the bait's scent, and taking advantage of the crabs' tendency to follow the current and go upstream to find the scent source, thereby improving the trapping effect. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of a rotating crab cage device according to a specific embodiment of the present invention.

[0022] Figure 2 yes Figure 1 Top view.

[0023] Figure 3 This is a schematic diagram of a rotating crab cage device according to a specific embodiment two of the present invention.

[0024] Figure 4 This is a schematic diagram of a rotating crab cage device according to a specific embodiment three of the present invention.

[0025] Figure 5 yes Figure 4 Top view.

[0026] Figure 6 This is a schematic diagram of a rotating crab cage device according to a specific embodiment four of the present invention.

[0027] In the picture:

[0028] Base 1;

[0029] Crab cage 2, supporting rollers 2.1;

[0030] Central shaft 3;

[0031] Side guide channel 4;

[0032] 5. Bait unit; 5.1. Corrugated telescopic soft sleeve; 5.2. Helical spring; 5.3. End cap;

[0033] Deflector plate 6;

[0034] 7. Buoyancy component;

[0035] Connecting rope 8;

[0036] Internal flow channel 9;

[0037] Guide slope 10. Detailed Implementation

[0038] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments:

[0039] Specific Implementation Example 1, such as Figure 1 , Figure 2 As shown, a rotating crab trap device includes a base 1, a crab trap 2, a bait unit 5, a guide plate 6, and two side guide channels 4. The bait unit 5 is located in the middle of the crab trap 2.

[0040] The crab trap 2 is rotatably mounted on the base 1 via a central shaft 3. A guide plate 6 is mounted on top of the crab trap 2. In this embodiment, the guide plate 6 is vertically distributed. As the ocean current flows through the crab trap 2, under the action of the guide plate 6, the crab trap 2 will rotate around the central shaft 3, so that one side of the crab trap 2 faces the ocean current, while the other side of the crab trap 2 remains away from the ocean current.

[0041] One of the two side guide channels 4 is located on the upstream side of the crab cage 2, and the other side guide channel 4 is located on the downstream side of the crab cage 2. Specifically, the two side guide channels 4 are distributed on opposite sides of the crab cage 2 along the guiding direction of the guide plate 6, such that one side guide channel 4 is located on the upstream side of the crab cage 2, and the other side guide channel 4 is located on the downstream side of the crab cage 2. One end of the side guide channel 4 is connected to the side of the crab cage 2 and forms a guide opening on the side of the crab cage 2, and the other end of the side guide channel 4 extends towards the center of the crab cage 2 and towards the bait unit 5. In this embodiment, the axis of the side guide channel is parallel to the guide plate. The opening area of ​​the side guide channel 4 gradually decreases from one end of the side guide channel 4 to the other end.

[0042] In this embodiment, the side guide channel 4 is made of a mesh plate, and the side wall of the side guide channel 4 has a number of mesh holes; or the side guide channel 4 is made of plastic or metal, and the side wall of the side guide channel 4 is a complete plastic side wall or metal side wall, that is, the side wall of the side guide channel 4 has no mesh holes.

[0043] In this embodiment, a rotating crab trap device is deployed to the seabed. The crab trap 2 is supported on the seabed by the base 1. Since the crab trap 2 is rotatably mounted on the base 1 via the central shaft 3 and the top of the crab trap 2 is provided with a guide plate 6, the crab trap 2 will rotate around the central shaft 3 under the action of the ocean current and the guide plate 6. This keeps one side of the crab trap 2 facing the ocean current and the other side facing away from the ocean current. As a result, one side guide channel 4 of the crab trap 2 is located on the upstream side of the crab trap 2, and the other side guide channel 4 is located on the downstream side of the crab trap 2. In this way, the ocean current will enter the crab trap 2 through the guide channel on the upstream side, and after flowing through the bait unit 5, it will flow out through the guide channel on the other side. Based on this, on the one hand, the flow resistance of the ocean current entering and exiting the crab trap 2 can be reduced by the guide channel, and on the other hand, the guide channel on the upstream side can guide, converge and accelerate the ocean current, so as to maximize the diffusion of the bait's scent with the current. This effectively utilizes the ocean current to diffuse the bait's scent, and takes advantage of the crabs' tendency to follow the current and go upstream to find the scent source, thereby improving the trapping effect.

[0044] Specifically, the crab cage 2 includes a top frame, a bottom frame, and side connecting rods linking the top frame and the bottom frame. This ensures the structural stability of the crab cage 2. The base 1 is either a steel structure base 1 or a concrete base 1.

[0045] Furthermore, the crab cage 2 is cylindrical. The cylindrical shape of the crab cage 2 minimizes its impact on the guiding effect of the guide plate 6. The base 1 can be a steel structure base 1 or a concrete base 1, which facilitates its fabrication.

[0046] Furthermore, the bottom of the crab cage 2 is provided with several support rollers 2.1 evenly distributed around the central axis 3. The support rollers 2.1 are close to the bottom edge of the crab cage 2 and are supported on the upper surface of the base 1. In this way, the crab cage 2 can be stably supported on the base 1 and can rotate stably around the central axis 3.

[0047] Furthermore, the guide vanes 6 consist of multiple pieces, all of which are parallel to each other. This helps to improve the guiding effect of the guide vanes 6 in conjunction with the ocean current, so that one side guide channel 4 of the crab cage 2 is located on the upstream side of the crab cage 2, and the other side guide channel 4 is located on the downstream side of the crab cage 2.

[0048] In this embodiment, the bait unit 5 includes a bait cylinder with several through holes on its side wall. The bait cylinder is connected to the crab trap 2 by a rope.

[0049] Specific embodiment two, such as Figure 3 As shown, the remaining structure of this embodiment is the same as that of specific embodiment one, except that,

[0050] A rotating crab trap device further includes a buoyancy component 7 located above the crab trap 2. A top through-hole is provided in the center of the top surface of the crab trap 2. The bait unit 5 includes a corrugated telescopic sleeve 5.1 closed at both ends. A spirally extending helical spring 5.2 is embedded in the inner wall of the corrugated telescopic sleeve 5.1. Several through holes are provided on the side wall of the corrugated telescopic sleeve 5.1. The lower end of the corrugated telescopic sleeve 5.1 is connected to the inside of the crab trap 2. In this embodiment, the lower end of the corrugated telescopic sleeve 5.1 is connected to the inner bottom surface of the crab trap 2 via a lower rope. The upper end of the corrugated telescopic sleeve 5.1 is connected to the buoyancy component 7 via a connecting rope 8, which passes through the top through-hole. The buoyancy component 7 is a float or a buoy. The sum of the weight of the corrugated telescopic sleeve 5.1, the weight of the connecting rope 8, and the weight of the bait inside the corrugated telescopic sleeve 5.1 is less than the buoyancy of the buoyancy component 7.

[0051] Currently, bait in bait baskets is usually piled up, which hinders the release of bait odor. To solve this problem, this solution improves the bait unit 5, creating a breathing-like effect that effectively releases bait odor. Specifically, when the ocean current is flowing, the buoyancy component 7 will pull the upper end of the corrugated telescopic sleeve 5.1 upwards under the action of the current, stretching the helical spring 5.2 and the corrugated telescopic sleeve 5.1. During this process, the inner cavity of the corrugated telescopic sleeve 5.1 increases, allowing seawater to pass through, and the through-holes on the side wall of the corrugated telescopic sleeve 5.1 enter the inner cavity. When the ocean current stops... When the current is slow or the current is weak, the helical spring 5.2 will overcome the buoyancy of the buoyancy component 7 and the force exerted by the current on the buoyancy component 7, causing the corrugated telescopic sleeve 5.1 to contract. During this process, the inner cavity of the corrugated telescopic sleeve 5.1 shrinks, and the seawater inside the inner cavity of the corrugated telescopic sleeve 5.1 flows out through the through holes on the side wall of the corrugated telescopic sleeve 5.1. Thus, through the stretching and contraction of the corrugated telescopic sleeve 5.1, a breathing effect is created, causing the bait inside the corrugated telescopic sleeve 5.1 to tumble and effectively release the bait's aroma.

[0052] At least one of the upper and lower ends of the corrugated telescopic sleeve 5.1 is provided with a detachable end cap 5.3. In this embodiment, the lower end of the corrugated telescopic sleeve 5.1 is closed, and the upper end of the corrugated telescopic sleeve 5.1 is provided with a detachable end cap 5.3, which is threadedly connected to the upper end of the corrugated telescopic sleeve 5.1. This facilitates the addition of bait into the corrugated telescopic sleeve 5.1.

[0053] Specific embodiment three, such as Figure 4 , Figure 5 As shown, a rotating crab trap device includes a base 1, a crab trap 2, a bait unit 5, a guide plate 6, an inner guide channel 9, and two side guide channels 4. The bait unit 5 is located in the middle of the crab trap 2.

[0054] The crab cage 2 is rotatably mounted on the base 1 via the central shaft 3.

[0055] A flow guide plate 6 is disposed on the top of the crab trap 2. The flow guide plate 6 is vertically distributed. In this embodiment, one end of the flow guide plate 6 is close to the center of the top of the crab trap 2, and the other end of the flow guide plate 6 extends to the top edge of the crab trap 2 or to the outer side of the top edge of the crab trap 2. As the ocean current flows through the crab trap 2, under the action of the flow guide plate 6, the crab trap 2 will rotate around the central axis 3, so that one side of the crab trap 2 always faces the ocean current, and the other side of the crab trap 2 always faces away from the ocean current.

[0056] One of the two side guide channels 4 is located on the upstream side of the crab cage 2, and the other side guide channel 4 is located on the downstream side of the crab cage 2. Specifically, the two side guide channels 4 are distributed on opposite sides of the crab cage 2 along the guiding direction of the guide plate 6, such that one side guide channel 4 is located on the upstream side of the crab cage 2, and the other side guide channel 4 is located on the downstream side of the crab cage 2. One end of the side guide channel 4 is connected to the side of the crab cage 2 and forms a guide opening on the side of the crab cage 2, and the other end of the side guide channel 4 extends towards the center of the crab cage 2 and towards the bait unit 5. In this embodiment, the axis of the side guide channel is parallel to the guide plate. The opening area of ​​the side guide channel 4 gradually decreases from one end of the side guide channel 4 to the other end.

[0057] In this embodiment, the side guide channel 4 is made of a mesh plate, and the side wall of the side guide channel 4 has a number of mesh holes; or the side guide channel 4 is made of plastic or metal, and the side wall of the side guide channel 4 is a complete plastic side wall or metal side wall, that is, the side wall of the side guide channel 4 has no mesh holes.

[0058] The inner guide channel 9 is fixed inside the crab cage 2 by a connector, and is located between the two side guide channels 4. The bait unit 5 is located inside the inner guide channel 9. One end of the inner guide channel 9 faces the upstream side of the crab cage 2, and the other end faces the downstream side of the crab cage 2. That is, one end of the inner guide channel 9 faces the downstream side of the side guide channel 4, and the other end faces the downstream side of the side guide channel 4. The opening area of ​​the inner guide channel 9 gradually decreases from the upstream side of the crab cage 2 towards the downstream side.

[0059] In this embodiment, the inner flow channel 9 is made of a mesh plate, and the sidewall of the inner flow channel 9 has a number of mesh holes; or the inner flow channel 9 is made of plastic or metal, and the sidewall of the inner flow channel 9 is a complete plastic sidewall or metal sidewall, that is, the sidewall of the inner flow channel 9 has no mesh holes.

[0060] In this embodiment, a rotating crab trap device is deployed to the seabed. The crab trap 2 is supported on the seabed by the base 1. Since the crab trap 2 is rotatably mounted on the base 1 via the central shaft 3 and the top of the crab trap 2 is provided with a guide plate 6, the crab trap 2 will rotate around the central shaft 3 under the action of the ocean current and the guide plate 6. This keeps one side of the crab trap 2 facing the ocean current and the other side facing away from the ocean current. As a result, one side guide channel 4 of the crab trap 2 is located on the upstream side of the crab trap 2, and the other side guide channel 4 is located on the downstream side of the crab trap 2. In this way, the ocean current will enter the crab trap 2 through the guide channel on the upstream side, and after flowing through the bait unit 5, it will flow out through the guide channel on the other side. Based on this, on the one hand, the flow resistance of the ocean current entering and exiting the crab trap 2 can be reduced by the guide channel, and on the other hand, the guide channel on the upstream side can guide, converge and accelerate the ocean current, so as to maximize the diffusion of the bait's scent with the current. This effectively utilizes the ocean current to diffuse the bait's scent, and takes advantage of the crabs' tendency to follow the current and go upstream to find the scent source, thereby improving the trapping effect.

[0061] On the other hand, when the ocean current enters the crab trap 2 through the guide channel on the upstream side, the current will diffuse inside the trap. Only a portion will flow out through the other side guide channel 4, while the rest will flow out through the netting on the side wall of the trap 2. The portion of the current flowing through the netting on the side wall of the trap 2 experiences greater flow resistance, which is not conducive to the downstream diffusion of the bait's aroma. To solve this problem, this embodiment first improves the guide plate 6 by placing one end of the guide plate 6 near the center of the top of the trap 2, and extending the other end of the guide plate 6 to the top edge of the trap 2 or to the outer side of the top edge of the trap 2. Thus, under the action of the current and the guide plate 6, one side of the trap 2 always faces the current, thereby ensuring that one side guide channel 4 of the trap 2 always faces the upstream side, while the other side guide channel 4 is always located on the downstream side of the trap 2 (see attached diagram). Figure 4 For example, under the action of the ocean current and the guide plate 6, the left side of the crab trap 2 always faces the ocean current, thus ensuring that the side guide channel 4 on the left side of the crab trap 2 always faces the upstream side of the crab trap 2, while the right guide channel 4 is always located on the downstream side of the crab trap 2. Based on this, an inner guide channel 9 is arranged between the two side guide channels 4, and the bait unit 5 is placed inside the inner guide channel 9. One end of the inner guide channel 9 faces the upstream side of the crab trap 2, and the other end faces the downstream side of the crab trap 2. The opening area of ​​the inner guide channel 9 gradually decreases from the upstream side of the crab trap 2 towards the downstream side. In this way, when the ocean current enters the crab trap 2 through the guide channel on the upstream side, it will be further guided and accelerated through the inner guide channel 9, and then flow out through the guide channel on the downstream side. This effectively reduces the diffusion of the ocean current within the crab trap 2, reduces flow resistance, and further improves the downstream diffusion effect of the bait scent, thereby further improving the trapping effect.

[0062] Specifically, the crab cage 2 includes a top frame, a bottom frame, and side connecting rods linking the top frame and the bottom frame. This ensures the structural stability of the crab cage 2. The base 1 is either a steel structure base 1 or a concrete base 1.

[0063] Furthermore, the crab cage 2 is cylindrical. The cylindrical shape of the crab cage 2 minimizes its impact on the guiding effect of the guide plate 6. The base 1 can be a steel structure base 1 or a concrete base 1, which facilitates its fabrication.

[0064] Furthermore, the bottom of the crab cage 2 is provided with several support rollers 2.1 evenly distributed around the central axis 3. The support rollers 2.1 are close to the bottom edge of the crab cage 2 and are supported on the upper surface of the base 1. In this way, the crab cage 2 can be stably supported on the base 1 and can rotate stably around the central axis 3.

[0065] Furthermore, the guide vanes 6 consist of multiple pieces, all of which are parallel to each other. This helps to improve the guiding effect of the guide vanes 6 in conjunction with the ocean current, so that one side guide channel 4 of the crab cage 2 is located on the upstream side of the crab cage 2, and the other side guide channel 4 is located on the downstream side of the crab cage 2.

[0066] Furthermore, the distance between the inner guide channel 9 and the side guide channel 4 located on the back-flow side of the crab trap 2 is greater than a set value L1. The set value L1 is 10 cm, 15 cm, 20 cm, 30 cm, or 50 cm. The distance between the inner guide channel 9 and the side guide channel 4 located on the front-flow side of the crab trap 2 is greater than a set value L2. The set value L2 is 10 cm, 15 cm, 20 cm, 30 cm, or 50 cm. In this way, crabs captured in the crab trap 2 can be prevented from climbing into the side guide channel 4 located on the back-flow side of the crab trap 2 through the inner cavity of the inner guide channel 9 and escaping; at the same time, crabs captured in the crab trap 2 can also be prevented from climbing into the side guide channel 4 located on the front-flow side of the crab trap 2 and escaping.

[0067] Furthermore, a guide slope 10 is provided between two adjacent guide plates 6. The guide slope 10 is close to the top edge of the crab trap 2, the lower edge of the guide slope 10 is close to or abuts the top surface of the crab trap 2, and the upper edge of the guide slope 10 extends obliquely upwards outwards from the crab trap 2. In this embodiment, the inclination angle of the guide slope 10 is 15-45 degrees. In this way, the sea current at the top of the crab trap 2 flows along the guide plate 6 to the top edge of the crab trap 2, and then is guided obliquely upwards through the guide slope 10, thereby driving a part of the sea current flowing out through the side guide channel 4 on the back side of the crab trap 2 to also be guided upwards. As is well known, the flow resistance is high near the seabed and low upwards away from the seabed, thereby further improving the downstream diffusion effect of the bait scent.

[0068] In this embodiment, the bait unit 5 includes a bait cylinder with several through holes on its side wall. The bait cylinder is connected to the crab trap 2 by a rope.

[0069] Specific embodiment four, such as Figure 6 As shown, the remaining structure of this embodiment is the same as that of specific embodiment three, except that,

[0070] A rotating crab trap device further includes a buoyancy component 7 located above the crab trap 2. A top through-hole is provided in the center of the top surface of the crab trap 2. A channel through-hole is provided in the upper part of the inner flow channel 9. The bait unit 5 includes a corrugated telescopic sleeve 5.1 closed at both ends. A spirally extending helical spring 5.2 is embedded in the inner wall of the corrugated telescopic sleeve 5.1. Several through holes are provided on the side wall of the corrugated telescopic sleeve 5.1. The lower end of the corrugated telescopic sleeve 5.1 is connected to the inside of the crab trap 2. In this embodiment, the lower end of the corrugated telescopic sleeve 5.1 is connected to the inner bottom surface of the crab trap 2 via a lower rope. The upper end of the corrugated telescopic sleeve 5.1 is connected to the buoyancy component 7 via a connecting rope 8, which passes through the channel through-hole and the top through-hole in sequence. The buoyancy component 7 is a float or a buoy. The sum of the weight of the corrugated telescopic sleeve 5.1, the weight of the connecting rope 8, and the weight of the bait inside the corrugated telescopic sleeve 5.1 is less than the buoyancy of the buoyancy component 7.

[0071] Currently, bait in bait baskets is usually piled up, which hinders the release of bait odor. To solve this problem, this solution improves the bait unit 5, creating a breathing-like effect that effectively releases bait odor. Specifically, when the ocean current is flowing, the buoyancy component 7 will pull the upper end of the corrugated telescopic sleeve 5.1 upwards under the action of the current, stretching the helical spring 5.2 and the corrugated telescopic sleeve 5.1. During this process, the inner cavity of the corrugated telescopic sleeve 5.1 increases, allowing seawater to pass through, and the through-holes on the side wall of the corrugated telescopic sleeve 5.1 enter the inner cavity. When the ocean current stops... When the current is slow or the current is weak, the helical spring 5.2 will overcome the buoyancy of the buoyancy component 7 and the force exerted by the current on the buoyancy component 7, causing the corrugated telescopic sleeve 5.1 to contract. During this process, the inner cavity of the corrugated telescopic sleeve 5.1 shrinks, and the seawater inside the inner cavity of the corrugated telescopic sleeve 5.1 flows out through the through holes on the side wall of the corrugated telescopic sleeve 5.1. Thus, through the stretching and contraction of the corrugated telescopic sleeve 5.1, a breathing effect is created, causing the bait inside the corrugated telescopic sleeve 5.1 to tumble and effectively release the bait's aroma.

[0072] At least one of the upper and lower ends of the corrugated telescopic sleeve 5.1 is provided with a detachable end cap 5.3. In this embodiment, the lower end of the corrugated telescopic sleeve 5.1 is closed, and the upper end of the corrugated telescopic sleeve 5.1 is provided with a detachable end cap 5.3, which is threadedly connected to the upper end of the corrugated telescopic sleeve 5.1. This facilitates the addition of bait into the corrugated telescopic sleeve 5.1.

[0073] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Any simple modifications, alterations, and equivalent transformations made to the above embodiments based on the technical essence of the present invention shall still fall within the protection scope of the present invention.

Claims

1. A rotary crabbing device, characterised in that, The application relates to a crab cage. The crab cage comprises a base, a crab cage arranged on the base through a central shaft, a bait unit arranged in the middle of the crab cage, a guide plate arranged on the top of the crab cage, two side guide channels, one of which is arranged on the windward side of the crab cage, the other of which is arranged on the leeward side of the crab cage, one end of the side guide channel is connected with the side of the crab cage and forms a guide opening on the side of the crab cage, the other end of the side guide channel extends to the center of the crab cage and faces the bait unit, the opening area of the side guide channel gradually decreases from one end to the other end, a buoyant member is arranged above the crab cage, the bait unit comprises a corrugated telescopic sleeve with closed upper and lower ends, a helical spring is embedded in the inner wall of the corrugated telescopic sleeve, a plurality of through holes are arranged on the side wall of the corrugated telescopic sleeve, the lower end of the corrugated telescopic sleeve is connected in the crab cage, and the upper end of the corrugated telescopic sleeve is connected with the buoyant member through a connecting rope, an inner guide channel is arranged in the crab cage and between the two side guide channels, the bait unit is arranged in the inner guide channel, one end of the inner guide channel faces the windward side of the crab cage, the other end of the inner guide channel faces the leeward side of the crab cage, and the opening area of the inner guide channel gradually decreases from the windward side of the crab cage to the leeward side. One end of the guide plate is close to the central part of the top of the crab cage, and the other end of the guide plate extends to the edge of the top of the crab cage or extends to the outside of the edge of the top of the crab cage. The distance between the inner guide channel and the side guide channel on the leeward side of the crab cage is greater than a set value L1, and the distance between the inner guide channel and the side guide channel on the windward side of the crab cage is greater than a set value L2. The guide plate is composed of multiple guide plates, and a guide inclined surface is arranged between two adjacent guide plates, the guide inclined surface is close to the edge of the top of the crab cage, the lower edge of the guide inclined surface is close to or abuts against the top surface of the crab cage, and the upper edge of the guide inclined surface extends upward and outward of the crab cage. At least one of the upper and lower ends of the corrugated telescopic sleeve is provided with a detachable end cover. The bottom of the crab cage is provided with a plurality of support rollers which are circumferentially distributed around the central shaft and sequentially arranged on the upper surface of the base, the support rollers are close to the edge of the bottom of the crab cage, and the support rollers are supported on the upper surface of the base. The guide plate is composed of multiple guide plates, and the guide plates are parallel to each other.

2. A rotary crab apparatus according to claim 1, characterised in that, The crab cage comprises a top frame, a bottom frame and a side connecting rod connecting the top frame and the bottom frame.

3. A rotary crab apparatus according to claim 2, characterised in that, The crab cage is in a cylindrical shape, and the base is a steel structure base or a concrete base.

4. A rotary crab apparatus according to claim 2 or 3, characterised in that, ​ 5. A rotary crab apparatus according to claim 1 or 2 or 3, characterised in that, ​ 6. A rotary crab apparatus according to claim 1 or 2 or 3, characterised in that, ​ 7. A rotary crab apparatus according to claim 1 or 2 or 3, wherein, ​ 8. A rotary crab apparatus according to claim 1 or 2 or 3, characterised in that, ​ 9. A rotary crab apparatus according to claim 1 or 2 or 3, characterised in that, ​

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