JPH036101Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to an improvement of a buoy for laying underwater cables.

Prior Art and Problems When laying a submarine cable on the seabed from land _L1 to land _L2 , it is first necessary to land the cable on land _L1 . However, in the past, a cable laying ship was anchored on the sea near land _L1 ,
The cable is sent out to sea from the cable laying ship while attaching buoys (car tire tubes, plastic spherical buoys, drum cans) to the cable at regular intervals, and the cable is floated to the sea by the buoys. The cable is being towed towards land _L1 by a tow rope connected to the end of the cable. When the tip of the cable reaches land _L1 , the cable is pulled a predetermined length onto land, and then the buoy is moved from the cable laying ship to land.
Cables are sunk by removing them in sequence toward the _L1 side.

However, conventionally, car tire tubes and drums have been used as buoys, and cables must be tied down with strings to attach them, and the strings must be released to remove them from the cables, which requires long hours. need. Further, it requires space for storage when not in use, which is also disadvantageous.

Purpose of the invention The purpose of the invention is to provide a buoy for laying underwater cables that can be attached to and removed from cables with a single touch, and that can be folded compactly and stored.

Structure of the invention The underwater cable laying buoy according to the invention is a underwater cable laying buoy which has rectangular pillow-shaped air chambers on both left and right sides, and a sheet-like cable mounting part in the middle of these air chambers, and has the above-mentioned structure. The air chamber and the cable mounting section are formed by folding the sheet on both sides of a single airtight sheet having a predetermined length, and sealingly fixing the three ends of the folded portion to the lower sheet. This structure is characterized in that rope locking rings are provided at both ends of the cable mounting section in the front and rear directions at positions offset from the center line of the cable mounting section.

Description of examples The present invention will be explained below with reference to the drawings.

FIG. 1A is a plan view showing a buoy according to the present invention, and FIG. 1B is a sectional view taken along line bb in FIG. 1A.

In Fig. 1A and Fig. 1B, 1 and 1 are rectangular pillow-shaped air chambers on both the left and right sides, and 2 is a sheet-like cable mounting section provided between both air chambers 1 and 1. These sheets are formed by folding a single airtight sheet having a predetermined length on both sides, and sealingly fixing the three ends of the folded portion to the lower sheet using heat fusion or adhesive. The airtight sheet may be a reinforcing fabric (eg, polyester fabric) coated with rubber or plastic (eg, vinyl chloride copolymer). Reference numerals 3 and 3 indicate air valves provided in each of the air chambers 1 and 1, and an air vent pipe is attached thereto. Reference numerals 4 and 4 indicate wire rope locking rings attached to both ends of the cable mounting section 2. Reference numerals 5 and 5 indicate reinforcing sheet pieces, which are heat-sealed to the sheet of the cable mounting section 2. The reinforcing sheet pieces and the ring are offset so as not to interfere with folding the buoy along the center line.

FIG. 2 and FIG. 3 are a plan view and a side view showing the state of use of the buoy according to the present invention. By consecutively passing the rope through the two front and rear rope locking rings 4, 4 (using the so-called wave stitching method), a group of buoys T is formed which are connected at a predetermined interval.

When using the cable for landing, the buoy group T is floated in an array on the sea near the cable laying ship, or loaded on the auxiliary ship B.
While stretching the buoy group connecting rope R in a straight line above the surface of the water where the cable D being let out from the cable laying ship is expected to enter the water and facing in the direction in which the cable is being paid out, the buoys A from the buoy group T are connected to land one by one. At point P in Figures 2 and 3, diver M places floating buoy A ₀ at the cable entry position by operating rope R, and connects cable D from cable installation vessel C to the buoy. Place it on the cable mounting part of _A0 . Therefore, if the buoy installation interval is S and the underwater weight of the cable is W, then the buoyant force F of the buoy is set to FSW, and as the cable is mounted on the buoy, it becomes sheet-like as shown in Figure 4. The cable mounting part 2 of the buoy is attached to the cable D, and the buoy and the cable are integrated.

After that, the buoys are paid out one by one, the cable D is paid out from the cable laying ship C, and the wire E is wound around the winch H.
The vehicle will be towed toward land L. After the cable reaches land, the cable is unloaded,
Afterwards, the buoys are removed from the cable one by one from the cable laying ship toward land, and the cable is sunk. In this removal, as shown in FIG. 4, it is only necessary to rotate the buoy by half a rotation around the cable D against the rotational moment due to buoyancy, so that the buoy can be easily removed.

Effects of the invention As described above, the underwater cable laying buoy according to the invention has a buoy structure with square pillow-shaped air chambers on both the left and right sides, and a sheet-shaped cable riding part in the middle of these air chambers, and A process in which the air chamber and the cable carrying part are folded from a single airtight sheet having a predetermined length into such a sheet on both sides, and the three ends of the folded part are sealed and fixed to the lower sheet. Since the structure is formed by applying the following steps, it can be manufactured at a very low cost, and the overall structure can be made compact and easy to handle, and can be folded into a sheet shape when stored.

In particular, in the buoy of the present invention, two rope locking rings are provided at both ends of the cable mounting section in the front and back direction, so the buoy connecting rope can be pulled through these two rings in a wave-stitched manner. By passing the rope through it in this way, it becomes possible to position the left and right air chambers of the buoy with a single rope, greatly simplifying the buoy connection work and the buoy tensioning work on the water surface.

In addition, in the above case, if the rope is slightly tensioned, the buoy can be latched to a predetermined position on the rope due to its ripple effect, and conversely, if it is loosened, the buoy can be moved in the desired direction on the rope by just applying a slight force. This makes it extremely easy to adjust the position of the buoy installation interval, and even when the cable is being unloaded, it can be adjusted without difficulty at the time the cable enters the water. Therefore, for underwater cables of different unit weights (normally, submarine cables are constructed in this way), the undersea part is sheathed with single-stranded iron wire and the part from the undersea part to the land part is sheathed with double iron wire. If the buoy group configuration is applied, the effect will be enormous. Of course, it goes without saying that even for cables of a plurality of sizes, since the spacing adjustment is simple as described above, it can be handled very quickly.

Moreover, because the rope can be held under pressure between the cable and the cable mounting part of the buoy due to its own weight, the cable, the rope, and the buoy can be compactly integrated, and the cable can be placed on land. Even if waves or the like occur during lifting, there is no risk that the spacing between the buoys will be disturbed and the buoys will come into contact with each other. Therefore, according to the buoy of the present invention, there is no need for the troublesome work of tying the buoy to a cable with a string as in the past, so the working time can be significantly shortened.

Furthermore, since the two rope locking rings of the present invention are not located at the center of the cable mounting section but at positions eccentric to the right from this center, it goes without saying that the cable mounting section can be folded well. When the cable is mounted, the cable can be mounted so that the axis of the cable is located on the center line of the cable mounting section. Therefore, the left and right air chambers can be maintained in a balanced buoyancy state, allowing stable cable landing work.

Incidentally, if the rope locking ring is located at the center of the mounting part, not only will it be a hindrance to folding, but the wire rope for connecting the buoy that will be passed through this ring will exist as a protrusion, and this protrusion This causes the cable to be loaded on the buoy to be displaced from side to side, making it difficult to load the cable at the center of the buoy. If the cable axis deviates from the center of the buoy in this way, the left and right air chambers will be in an unstable buoyancy state, and in some cases, the cable may fall off the buoy, making it impossible to expect good landing operations. In addition, in order to prevent the cable from falling off in the above case, it is possible to tie both air chambers from the surrounding area with a tightening band after mounting the cable, but in this case, it is necessary to perform the cumbersome binding and release process, which makes the landing work difficult. It is impossible to improve sexuality.

[Brief explanation of the drawing]

FIG. 1A is a plan view showing a buoy for laying underwater cables according to the present invention, FIG. 1B is a sectional view taken along line bb in FIG. 1A, and FIGS. A plan view and a side view showing the method of landing the underwater cable used, and FIG. 4 is a side view showing the state in which the buoy of the present invention is attached to the cable. In the figure, 1, 1 is an air chamber, 2 is a cable mounting part, 3, 3 is an air valve, 4, 4 is a rope locking ring, 5, 5 is a reinforcing sheet piece, A is a buoy, and B is an auxiliary ship. , C is a cable laying ship, D is a cable, E is a wire, H is a winch, L is a land, M is a diver, and R is a rope.

Claims (1)

[Scope of utility model registration request] An underwater cable laying buoy with rectangular pillow-shaped air chambers on both left and right sides and a sheet-like cable mounting section in the middle of these air chambers, wherein the air chamber and the cable mounting section have a predetermined length. Fold the sheet on both sides into one airtight sheet,
It is formed by sealing and fixing the three ends of the folded part to the lower sheet, and rope locking rings are attached to both ends of the cable mounting part in the front and rear direction. A buoy for laying underwater cables, characterized in that it is installed at a position offset from the center line of the buoy.