JP7630115B2 - Binding device for tubular bodies and float for fish and shellfish farming - Google Patents

Description

The present invention relates to a float for fish and shellfish farming that is set afloat on the surface of the water, such as the sea, lake, or pond, and a fastener for fastening multiple tubular bodies that make up the float.

Traditionally, in aquaculture, it has been common to float floating bodies such as rafts and fish cages on the water surface to raise fish and shellfish. For example, a float for aquaculture of fish and shellfish disclosed in Patent Document 1 comprises a main frame having a plurality of metal or resin rod-shaped bodies and a plurality of floats made of foam made of synthetic resin material, and the main frame is assembled by connecting each of the floats to each of the rod-shaped bodies arranged so as to form a rectangular frame in a plan view.

However, floats made of foam made of synthetic resin material, such as those in Patent Document 1, have low resistance to the impact of waves generated by typhoons and the erosion of living organisms, and if they are left floating on the water surface for a long period of time, they will break into pieces, or become damaged and detached from the main frame, turning into floating debris on the water surface, causing problems not only with polluting the seas and lakes, but also with affecting the ecosystem.

To avoid this, it is conceivable to make the float's main frame lightweight by constructing it from multiple tubular bodies, and to increase the overall volume of the main frame, thereby creating a structure that gives the float the necessary buoyancy without using floats as in Patent Document 1.

Microfilm of Utility Model Application No. 54-091677 (Utility Model Application No. 56-8172)

However, if you try to increase the volume of the entire main frame by making the tubular body itself larger, it becomes more cumbersome to transport the tubular body and installation work becomes more difficult. Furthermore, the rigidity of the tubular body increases, making it difficult to maintain the shape of the tubular body after bending it.

On the other hand, when attempting to increase the overall volume of the main frame by bundling multiple tubular bodies, transport, installation, and bending are each easier than when increasing the overall volume of the main frame by making the tubular bodies themselves larger. However, it is necessary to bundle each tubular body together, and the conventional methods of tying with wire or connecting with multiple brackets and fastening members not only involve cumbersome work, but also have the risk of the relative positions of the tubular bodies at the bundling points becoming misaligned if force is suddenly applied during use.

The present invention was made in consideration of these points, and its purpose is to provide a fastener that easily and firmly connects the tubular bodies that make up a float, preventing the tubular bodies from shifting in their relative positions during use, and a float that has the necessary buoyancy and is formed by connecting the tubular bodies using the fastener.

To achieve the above object, the present invention is characterized in that each tubular body and the fastener are connected using electrofusion bonding or heat fusion bonding.

Specifically, the following solution was implemented for a fastener that fastens multiple tubular bodies constituting a float for fish and shellfish farming at a specified radial distance apart.

That is, in the first invention, the fastener and each of the tubular bodies are each formed of a resin material and are connected to each other by electrofusion bonding or heat fusion bonding , and the fastener is provided with a fitting portion into which the tubular bodies are fitted when connecting the tubular bodies, and the fitting portion is a fitting recess into which the tubular bodies are fitted in the radial direction .

In a second invention, in the first invention, the fitted portion is arranged in parallel at a predetermined interval in the radial direction of the tubular body when it is fitted into the fitted portion.

A third invention is characterized in that in the first invention, the fastener has at least one pair of mating recesses formed on the front and back sides thereof, the mating recesses opening to opposite sides.

The fourth invention is characterized in that, in the first invention, the surface of the fastener has a plurality of mating recesses that open toward the surface side of the fastener, which are arranged side by side at predetermined intervals in the radial direction of the tubular body when it is mated with the mating recesses and in a direction perpendicular to the mating direction.

The fifth invention is characterized in that, in the fourth invention, the back surface of the fastener has a plurality of mating recesses that open to the back surface side of the fastener, which are arranged side by side at predetermined intervals in the radial direction of the tubular body when it is mated with the mating recesses and in a direction perpendicular to the mating direction.

A sixth invention relates to a fastening device for fastening a plurality of tubular bodies constituting a float for fish and shellfish farming at a predetermined radial interval, the fastening device and each of the tubular bodies being formed from a resin material and connected to each other by electrofusion joining or heat fusion joining, and the fastening device is configured so that other fastening devices excluding the fastening device itself can be connected to the fastening device.

The seventh invention is characterized in that in any one of the first to sixth inventions, an electric heating wire for electrofusion joining is embedded in an area inside the fastener corresponding to the connection position of the tubular body.

The eighth invention is characterized in that, in any one of the first to sixth inventions, the fastener is provided with a resin sheet that can be laid in an area corresponding to the connection position of the tubular body and has an electric heating wire for electrofusion joining embedded therein.

A ninth invention is characterized in that in any one of the first to fifth, seventh and eighth inventions, the fastener is configured to be connectable to other fasteners excluding the fastener itself.

In a tenth invention, a float for fish and shellfish farming is characterized in that it comprises any one of the fastening devices according to the first to ninth inventions and a plurality of the tubular bodies fastened together by the fastening device.

In the first invention, the binder and each tubular body are integrated by simply contacting the binder and each tubular body and passing an electric current through the contact portion, or by simply contacting a heated portion of the binder and a heated portion of each tubular body, so that the binder and each tubular body can be easily connected. In addition, since the binder and each tubular body are connected to each other by fusion, the binder and each tubular body are firmly fixed, and even if a force is suddenly applied, the binder can prevent the positional relationship of each tubular body from being shifted by the tubular body. In addition, in the first invention, when the binder and the tubular body are connected, the tubular body is fitted into the fitting portion of the binder, so that the connection position of the tubular body relative to the binder is accurately determined. Therefore, the tubular body can be connected to the binder at an accurate position. In addition, in the first invention, the work of fitting the tubular body into the fitting portion is simplified, so that the time required for assembly work can be shortened.

In the second invention, when each tubular body is fitted into each fitting portion of the fastener, the tubular bodies are lined up in a precise position with a predetermined interval between them, so that the multiple tubular bodies can be assembled to the fastener without variation.

In the third invention, when connecting multiple tubular bodies, the binder is positioned inside the multiple tubular bodies, so that the volume occupied by the binder can be reduced and the material costs of the binder can be kept low.

In the fourth aspect of the present invention, when the tubular bodies are fitted into the fitting recesses of the fastener, the tubular bodies are neatly lined up at a predetermined interval, so that the tubular bodies can be connected to the fastener in accurate positions and in a neatly arranged state.

In the fifth aspect of the present invention, when the tubular bodies are fitted into the fitting recesses of each fastener, the tubular bodies are neatly arranged in two rows at a predetermined interval, so that the tubular bodies can be connected to one fastener at accurate positions and in a state of being arranged in two rows.

In the seventh invention, since the heating wire is embedded in the fastener, the transport and installation of the fastener is easier than in a case where the heating wire is not embedded in the fastener, and the workload on workers can be reduced.

In the eighth invention, it is only necessary to prepare resin sheets equal to the number of tubular bodies to be connected to the fastener, making it possible to produce a fastener at a lower cost than the seventh invention in which heating wires are embedded in advance in positions corresponding to all of the mating recesses.

In the sixth and ninth aspects of the present invention, since a plurality of fasteners can be connected, the number of tubular bodies arranged in parallel can be increased by increasing the number of fasteners as necessary.

In the tenth invention, since each tubular body constituting the float can be easily connected by fasteners, a float made up of a number of tubular bodies sufficient to obtain the required buoyancy can be easily produced.

1 is a plan view showing a raft for breeding fish and shellfish according to a first embodiment of the present invention. FIG. FIG. 2 is an enlarged view of part II in FIG. FIG. 3 is a view taken along the arrow III in FIG. 1 . FIG. 4 is a view taken along the arrow IV in FIG. 3 . FIG. 5 is a view taken along the arrow V in FIG. 4 . 1 is a perspective view of a fastener according to a first embodiment of the present invention. FIG. FIG. 5 is a view corresponding to FIG. 4 according to a second embodiment of the present invention. FIG. 5 is a view corresponding to FIG. 4 according to a third embodiment of the present invention.

The following describes in detail an embodiment of the present invention with reference to the drawings. Note that the following description of the preferred embodiment is essentially merely exemplary.

First Embodiment of the Present Invention
1 shows a raft 1 (float) for fish and shellfish farming according to embodiment 1 of the present invention. The raft 1 is used by floating it on the water surface during aquaculture, and includes a plurality of tubular bodies 2 arranged concentrically in a circular ring shape centered on a center line C1 in a plan view, and a plurality of fasteners 3 for fastening the tubular bodies 2 at predetermined intervals in the radial direction of the tubular bodies 2.

There are three types of tubular bodies 2 with different ring sizes centered around the center line C1, and the raft 1 has two of each of the three types of tubular bodies 2 with different ring sizes.

The tubular body 2 comprises a pipe body 2a obtained by bending a polyethylene pipe so that it has a circular shape in a plan view, and a joint part 2b which is a socket joint that connects the ends of the pipe body part 2a, and an electric heating wire (not shown) for electrofusion joining (hereinafter referred to as EF joining) is embedded in the joint part 2b.

The tubular body 2 is obtained by inserting each end of the tube main body 2a, which is formed into a circular shape by bending, into the two sockets of the joint 2b, respectively, and passing an electric current through an electric heating wire (not shown) to generate heat, thereby fusing the tube main body 2a and the joint 2b together by heating and melting them to form a single unit.

As shown in FIG. 1, the fasteners 3 are arranged at eight positions P1 to P8 that are equally spaced apart in the circumferential direction around the center line C1 of the tubular body 2 to fasten each tubular body 2, and at each of positions P1 to P8, two fasteners 3 fasten each tubular body 2, as shown in FIG. 3.

In other words, in the raft 1 according to the first embodiment of the present invention, each tubular body 2 is bound together using 16 binding devices 3, and three tubular bodies 2 are arranged in two tiers, one above the other, in the radial direction around the center line C1.

As shown in Figures 5 and 6, the fastener 3 is made of the same polyethylene material as the tubular body 2, and includes a fastener body 4 that is elongated, flat, and generally rectangular, and three resin sheets 5 that are regular octagonal in plan view.

The fastener body 4 has a generally band-shaped surface portion 4a that extends in the longitudinal direction of the fastener body 4, a pair of side portions 4b that protrude parallel to each other from both longitudinal ends of the surface portion 4a toward the back surface, and a band-shaped back surface portion 4c that bridges the protruding ends of both side portions 4b.

Between the two side surfaces 4b, a pair of partition walls 4d are provided, dividing the space between the two side surfaces 4b into three equally spaced sections, and each partition wall 4d bridges the front surface 4a and the back surface 4c.

As shown in Figures 3 and 4, the surface portion 4a is provided with three fitting recesses 4e (fitted portions) into which the tubular body 2 is fitted.

When viewed from the side perpendicular to the longitudinal direction of the fastener body 4, each fitting recess 4e is formed by curving the front surface 4a toward the back surface 4c in an arch shape, and the curved surface has a shape that corresponds to the outer peripheral surface of the tubular body 2.

In other words, when the tubular body 2 is connected to the fastener 3, the tubular body 2 is fitted into the fitting recess 4e in the radial direction of the tubular body 2.

The fitting recesses 4e are provided at equal intervals at a predetermined distance in the longitudinal direction of the fastener body 4. In other words, three fitting recesses 4e are provided side by side at a predetermined distance in the radial direction of the tubular body 2 when fitted into the fitting recesses 4e, and in a direction perpendicular to the fitting direction.

In the first embodiment, at each of positions P1 to P8, as shown in FIG. 3, two fasteners 3 are integrated by fusing the back surfaces 4c together, and the mating recesses 4e of each fastener 3 are open on opposite sides.

In other words, the fastener 3 is configured to be connectable to other fasteners 3 other than the fastener 3 in question.

The resin sheet 5 is made of the same polyethylene material as the tubular body 2 and the fastener 3, and has a through hole 5b formed in the center.

An electric heating wire 5a for EF bonding is embedded inside the resin sheet 5 so that it extends in a spiral shape around the through hole 5b.

A controller 6 is connected to the end of the heating wire 5a, and the controller 6 is capable of passing an electric current through the heating wire 5a to generate heat.

The resin sheet 5 is formed with a thickness that allows it to be flexible, and can be laid along the area corresponding to the connection position of the tubular body 2 in the fastener 3, i.e., along the surface of each fitting recess 4e.

Then, with the resin sheets 5 set in the fitting recesses 4e of the fasteners 3, the tubular bodies 2 are fitted into the fitting recesses 4e, and the controller 6 heats the heating wires 5a embedded in the resin sheets 5 to fuse the corresponding parts of the tubular bodies 2 and fasteners 3, thereby connecting the tubular bodies 2 and fasteners 3 to obtain the raft 1.

Next, the assembly method for the raft 1 of embodiment 1 of the present invention will be described in detail.

First, six polyethylene pipes, six socket joints made of polyethylene material, and 16 fasteners 3 are prepared. The polyethylene pipes may be straight, or may have a tendency to curl due to being stored in a coiled state.

Next, the worker bends the polyethylene pipe into a circular shape, bringing each end of the polyethylene pipe close to each other, and inserts them into each of the sockets of the socket joints. Then, by passing an electric current through an electric heating wire (not shown) embedded in the socket joint, the polyethylene pipe and the socket joint are heat-fused together to obtain a tubular body 2 consisting of a pipe main body portion 2a and a joint portion 2b. In the first embodiment of the present invention, three types of tubular bodies 2 with different ring sizes centered on the center line C1 are created, two of each type.

Next, as shown in FIG. 4, two of each fastener 3 are prepared, and the back surfaces 4c of each fastener 3 are fused together by EF bonding so that the mating recesses 4e of each fastener 3 face in opposite directions, creating a combined unit of eight fasteners 3 in total.

Furthermore, as shown in Figures 4 and 5, a resin sheet 5 is laid in the fitting recess 4e of each fastener 3, and the resin sheet 5 is attached to the fitting recess 4e by EF joining.

Then, the eight binding devices 3 are arranged in a ring shape at equal intervals, and each tubular body 2 is fitted into each fitting recess 4e. The controller 6 is then started to heat the heating wires 5a of each resin sheet 5, fusing the corresponding portions of each tubular body 2 and binding device 3, thereby obtaining a raft 1 in which each tubular body 2 and binding device 3 are connected.

As described above, according to the first embodiment of the present invention, each tubular body 2 constituting the raft 1 can be easily connected by the fasteners 3, so that the raft 1 can be easily made from the number of tubular bodies 2 that can provide the required buoyancy.

In addition, each tubular body 2 and the fastener 3 can be integrated simply by bringing them into contact with each other and passing an electric current through the contact portion, so each tubular body 2 and the fastener 3 can be easily connected.

In addition, because each tubular body 2 and the fastener 3 are connected to each other by fusion, each tubular body 2 and the fastener 3 are firmly fixed to each other, and even if a force is suddenly applied, each fastener 3 can prevent the positional relationship of each tubular body 2 from shifting.

In addition, when the tubular body 2 and the fastener 3 are connected, the tubular body 2 is fitted into the fitting recess 4e of the fastener 3, so the connection position of the tubular body 2 relative to the fastener 3 is accurately determined. Therefore, the tubular body 2 can be connected to the fastener 3 at an accurate position.

When each tubular body 2 is fitted into each fitting recess 4e of the fastener 3, the tubular bodies 2 are lined up in a precise position with a predetermined interval between them. Therefore, multiple tubular bodies 2 can be assembled to the fastener 3 without variation.

In addition, the tubular body 2 and the mating recess 4e can be mated simply by moving the tubular body 2 in the radial direction, so the task of mating the tubular body 2 with the mating recess 4e is simple and the time required for assembly can be reduced.

When each tubular body 2 is fitted into each fitting recess 4e of each fastener 3, the tubular bodies 2 are neatly lined up at a predetermined interval. Therefore, each tubular body 2 can be connected to the fastener 3 in an accurate position and neatly arranged side by side.

In addition, a resin sheet 5 is laid between the tubular body 2 and the fastener 3, and the heating wire 5a embedded in the resin sheet 5 is heated to integrate the tubular body 2 and the fastener 3. This means that only the number of resin sheets 5 required for the number of tubular bodies 2 to be connected to the fastener 3 needs to be prepared, and there is no need to prepare resin sheets 5 in advance in the number corresponding to all of the mating recesses 4e, making it possible to produce a fastener 3 with reduced component costs.

In addition, since multiple fasteners 3 can be connected, the number of tubular bodies 2 arranged side by side can be increased by increasing the number of fasteners 3 as necessary.

Second Embodiment of the Invention
7 shows a fastener 3 according to a second embodiment of the present invention. Since the second embodiment is similar to the first embodiment except for a portion of the structure of the fastener 3 which is different from that of the first embodiment, the same parts as those in the first embodiment are denoted by the same reference numerals, and only the other different parts will be described.

The back surface 4c of the fastener 3 of embodiment 2 has three fitting recesses 4f into which the tubular body 2 is fitted.

When viewed from the side perpendicular to the longitudinal direction of the fastener body 4, each fitting recess 4f is provided by forming a shape in which the back surface 4c is curved in an arch shape toward the front surface 4a, and the curved surface has a shape that corresponds to the outer peripheral surface of the tubular body 2.

That is, the fitting recess 4f is open on the opposite side to the fitting recess 4f formed on the surface portion 4a, and when the tubular body 2 is connected to the fastener 3 at the fitting recess 4f, the tubular body 2 fits into the fitting recess 4f in the radial direction of the tubular body 2.

Each of the fitting recesses 4f provided on the back surface portion 4c is located at a position corresponding to each of the fitting recesses 4e provided on the front surface portion 4a. That is, the three fitting recesses 4f are arranged side by side at a predetermined interval in the radial direction of the tubular body 2 when fitted into the fitting recesses 4f and in a direction perpendicular to the fitting direction.

In other words, the fastener 3 of embodiment 2 has three pairs of mating recesses 4e and 4f on the front and back sides that open to opposite sides.

In the region corresponding to each fitting recess 4e and each fitting recess 4f inside the fastener 3 of the second embodiment, an electric heating wire 5a for EF joining is embedded. When the tubular body 2 is connected to the fastener 3, the electric heating wire 5a is heated while the tubular body 2 is fitted into each fitting recess 4e and each fitting recess 4f, so that the tubular body 2 and the fastener 3 can be fused to each other without using a resin sheet 5 as in the first embodiment.

As described above, according to the second embodiment of the present invention, when each tubular body 2 is fitted into each fitting recess 4e and each fitting recess 4f of the fastener 3, the tubular bodies 2 are neatly arranged in two rows with a predetermined interval between them. Therefore, each tubular body 2 can be connected to one fastener 3 in an accurate position and in a state where it is arranged in two rows.

In addition, because the heating wire 5a for EF joining is embedded in the fastener 3, the transport and installation of the fastener 3 is easier than when the heating wire 5a is not embedded in the fastener 3, reducing the workload of the worker.

In addition, when connecting multiple tubular bodies 2, the fastener 3 is positioned inside the multiple tubular bodies 2, so the volume occupied by the fastener 3 can be reduced, and the material cost of the fastener 3 can be kept low.

Third Embodiment of the Invention
8 shows a fastener 3 according to a third embodiment of the present invention. Since the third embodiment is similar to the first embodiment except for a portion of the structure of the fastener 3 which is different from that of the first embodiment, the same parts as those of the first embodiment are denoted by the same reference numerals, and only the other different parts will be described.

The fastener body 4 of the third embodiment has a flat surface portion 4a and a flat back surface portion 4c, and the space S1 surrounded by the surface portion 4a, the side portions 4b, and the back surface portion 4c is provided with a fitting cylindrical portion 4g (fitted portion) into which the tubular body 2 can be fitted.

The center line of the cylindrical fitting portion 4g extends in the communication direction of the space S1, and three of them are arranged side by side at a predetermined interval in the longitudinal direction of the fastener body 4.

Each fitting cylindrical section 4g has an electric heating wire 5a for EF joining embedded inside, and when connecting the tubular body 2 to the fastener 3, the electric heating wire 5a is heated while the tubular body 2 is fitted into each fitting cylindrical section 4g, so that the tubular body 2 and the fastener 3 can be fused together.

As described above, according to the third embodiment of the present invention, even if the portion where the tubular body 2 is connected to the fastener 3 is cylindrical and has a structure in which the tubular body 2 is inserted and fitted, it is possible to obtain the same effects as those of the first and second embodiments.

In the first to third embodiments of the present invention, EF bonding is used to bond each tubular body 2 to the binder 3, but this is not limiting, and each tubular body 2 may be connected to the binder 3 using heat fusion bonding (HF bonding). In this way, each tubular body 2 and the binder 3 become integrated simply by bringing the heated portion of the binder 3 into contact with the heated portion of each tubular body 2, so that each tubular body 2 and the binder 3 can be easily connected.

In addition, in the first to third embodiments of the present invention, the number of tubular bodies 2 of the raft 1 is six, but this is not limited thereto, and the number of tubular bodies 2 of the raft 1 may be one to five, or seven or more.

In addition, in the first to third embodiments of the present invention, the tubular bodies 2 are bound at eight locations using the binding device 3, but the number of locations where the tubular bodies 2 are bound using the binding device 3 may be any other number as long as the relative positions of the tubular bodies 2 do not vary.

In addition, in the first to third embodiments of the present invention, the tubular bodies 2 are bound together using the binding device 3 at equally spaced positions in the circumferential direction around the center line C1, but the binding positions do not have to be at equally spaced positions.

In addition, in the first embodiment of the present invention, each fastener 3 is provided with multiple mating recesses 4e, but it is also possible to provide only one on each.

In addition, in the second embodiment of the present invention, three pairs of mating recesses 4e and 4f that open to opposite sides are formed on the front and back sides of the fastener 3, but only one pair may be formed, or four or more pairs may be formed.

In addition, in the first and second embodiments of the present invention, the tubular body 2 is connected to the front surface portion 4a or the back surface portion 4c of the fastener 3, but the tubular body 2 may be connected to the side surface portion 4b.

In addition, in the first and third embodiments of the present invention, the fasteners 3 are connected to each other by EF joining, but they may also be connected by an engagement means such as an engagement claw and an engagement hole.

In addition, in the first and third embodiments of the present invention, the two fasteners 3 are connected to each other, and then each tubular body 2 is connected to each fastener 3 to assemble the raft 1. However, the raft 1 may also be assembled by first connecting each tubular body 2 to each fastener 3, and then connecting the two fasteners 3 to each other.

The fasteners 3 in the first to third embodiments of the present invention are used to fasten the tubular bodies 2 in a circular ring shape, but can also be used to connect linear tubular bodies 2 in a lattice pattern to create rafts and other floating structures such as fish pens.

The present invention is suitable for a float for fish and shellfish farming that is set afloat on the surface of the water, such as the sea, lake, or pond, and for a fastening device that fastens multiple tubular bodies that make up the float.

1. Raft (floating body)
2 Tubular body 3 Fastener 4e Fitting recess (fitted portion)
4f Fitting recess (fitted portion)
4g Fitting cylindrical part (fitted part)
5. Plastic sheet

Claims (10)

A fastener for fastening a plurality of tubular bodies constituting a floating body for fish and shellfish farming at a predetermined radial interval,
The fastener and each of the tubular bodies are formed of a resin material and are connected to each other by electrofusion bonding or heat fusion bonding ,
the fastener is provided with a fitted portion into which the tubular bodies are fitted when the tubular bodies are connected,
The fastener is characterized in that the fitted portion is a fitting recess into which the tubular body is fitted in the radial direction . The fastener according to claim 1 ,
The fastener is characterized in that a plurality of the fitted portions are arranged side by side at predetermined intervals in the radial direction of the tubular body when fitted to the fitted portions. The fastener according to claim 1 ,
The fastener is characterized in that at least one pair of the fitting recesses, which are open to opposite sides, are formed on the front and back sides of the fastener. The fastener according to claim 1 ,
A fastener characterized in that a surface of the fastener has a plurality of mating recesses that open toward the surface side of the fastener, the mating recesses being arranged side by side at predetermined intervals in the radial direction of the tubular body when mated with the mating recesses and in a direction perpendicular to the mating direction. The fastener according to claim 4 ,
A fastener characterized in that a back surface of the fastener has a plurality of mating recesses which open to the back surface side of the fastener and are arranged side by side at predetermined intervals in the radial direction of the tubular body when mated with the mating recesses and in a direction perpendicular to the mating direction. A fastener for fastening a plurality of tubular bodies constituting a floating body for fish and shellfish farming at a predetermined radial interval,
The fastener and each of the tubular bodies are formed of a resin material and are connected to each other by electrofusion bonding or heat fusion bonding,
A fastener configured so that other fasteners other than said fastener can be connected to said fastener. The fastener according to any one of claims 1 to 6 ,
A fastener, characterized in that an electric heating wire for electrofusion bonding is embedded inside the fastener in a region corresponding to a position where the tubular bodies are joined. The fastener according to any one of claims 1 to 6 ,
A fastener comprising a resin sheet that is installable in an area of the fastener that corresponds to the connection position of the tubular bodies and in which an electric heating wire for electrofusion bonding is embedded. The fastener according to any one of claims 1 to 5, 7 and 8 ,
A fastener configured so that other fasteners other than said fastener can be connected to said fastener. A fastener according to any one of claims 1 to 9 ;
A float for fish and shellfish farming, comprising a plurality of the tubular bodies fastened together by the fastening device.