Floating bag flap gate and waterproofing method using same

Abstract

This floating bag flap gate (1) is configured such that: when rainwater (W) intrudes into a gutter (2) and the water level (H) rises, buoyancy is generated in an expansion member (10); the expansion member is erected while rotating around an expansion member fixing part (3) serving as a fulcrum, whereby the expansion member floats and forms a waterproof wall; a high dam height is maintained by an anchoring at the fixing part and a bag structure of the expansion member; in a state in which the water level of the rainwater fills the gutter, the center of gravity (O) of the expansion member filled with gas (A) is located outward of a side surface position of a site inside (S1) of the gutter; when the water level of the intruding rainwater exceeds the level of the gutter and the water level rises, a tensile load is generated in a free base end part (11a) of a base end part (11), where the free base end part is not fixed by the fixing part, and an elastic restoring force derived from the tensile load is generated, whereby the expansion member is pulled back in the direction of a site outside (S2); and when the water level of the rainwater falls to a state in which the the gutter is filled, the center of gravity of the expansion member is located outward of the side surface position of the site inside of the gutter, whereby the expansion member is automatically stored in the gutter without power.

Description

Floating bag body flap gate and waterproof method using the same

[0001] The present invention relates to a floating bag body flap gate and a waterproof method using the same.

[0002] Although measures for basin water control are being promoted mainly for specific urban rivers by the state and local governments, conventional measures such as raising the height of river levees require enormous time and costs and can only be carried out for rivers with a considerably high risk.

[0003] On the other hand, due to abnormal weather caused by global warming, floods due to the occurrence of linear precipitation bands occur somewhere every year, and it is not surprising that floods occur in rivers and water channels anywhere in the country.

[0004] In particular, public facilities such as hospitals, welfare facilities, and government offices, and large-scale facilities such as large shopping centers are facilities that help save the lives and livelihoods of disaster victims. If their functions are lost due to disasters, the situation will become more serious. Therefore, there is a strong demand for devices to prevent the facilities from being flooded.

[0005] As a means to prevent the loss of functions due to flooding of such facilities, conventionally, measures such as attaching sandbags, water bags, and water stop plates to the entrances and exits of buildings have been taken.

[0006] However, in large facilities, there are many buildings and entrances and exits. To attach sandbags, water bags, water stop plates, etc. to all of them requires a large number of people and time. Especially in recent heavy rains, flooding may occur in a short time of several tens of minutes. There is no time to attach sandbags, water bags, water stop plates, etc. to all the entrances and exits, and it is also difficult to secure personnel.

[0007] In addition, in response to the risk information of weather forecasts, it may be considered to attach sandbags, water bags, water stop plates, etc. to the entrances and exits in advance if there is any risk. However, in most cases, flooding does not occur even if they are actually attached, and attaching them will hinder the operations of hospitals, government offices, and the business of shopping centers. Therefore, it is also difficult to install them in advance considering the risks.

[0008] As a means to solve the above problems in attaching sandbags, water bags, water stop plates, etc. to the entrances and exits, floating flap gates have been proposed and partially implemented (for example, Patent Documents 1 and 2).

[0009] A floating flap gate is an automatically retractable waterproof gate installed at the entrance of a building. When water seeps into the building entrance, buoyancy is generated in the retractable gate body, causing it to rise and become a waterproof wall.

[0010] Door stops are provided on both sides of the door body, and sealing members are attached for waterproofing.

[0011] Typically, a door made of a rigid metal body has an air chamber inside, but it is heavy, and the sliding resistance with the door stopper due to the sealing member is also large, so the door cannot stand upright by the buoyancy of the door itself alone. Therefore, a counterweight is suspended inside the door stopper at the end of the door to help it stand upright.

[0012] Furthermore, stoppers and tethering members are provided to prevent the heavy, upright door from falling over by more than 90 degrees.

[0013] With this configuration, it is no longer necessary to manually install and remove the sandbags, water bags, or water barriers each time, as was required with conventional methods.

[0014] Japanese Patent Publication No. 2003-253912, Japanese Patent No. 5762822

[0015] However, such waterproofing devices require a very complex and highly precise hinge structure to raise and lower the rigid, heavy door body. Furthermore, a separate waterproof sheet needs to be installed to prevent water leakage at the hinge, but an additional structure is needed to prevent water leakage due to sagging of the rubber sheet at the joint between the waterproof sheet and the door body, making it very costly.

[0016] Furthermore, in large-scale facilities, it is difficult to install them at all of the more than 100 entrances and exits. Even if they were installed at all entrances and exits, there was a problem that emergency vehicles and official vehicles parked in the parking lot would be submerged, hindering recovery efforts.

[0017] Therefore, there is a need for an automatic, retractable waterproofing device that can cover the entire facility site at once, rather than just the entrances and exits of individual buildings, and that does not require prior installation.

[0018] To meet these requirements, installing the conventional floating flap gate described above would necessitate connecting multiple door bodies made of rigid metal, requiring the addition of sealing structures at the joints and the installation of multiple door stops and counterweights. This would result in extremely high costs for covering the perimeter of a facility on a large site.

[0019] This invention solves the problems of the prior art described above, and proposes an automatic, retractable waterproofing device that can cover the entire facility site at once and does not require prior installation. Furthermore, it proposes a bag-type flap gate that is extremely simple, low-cost, and highly reliable compared to conventional floating flap gates.

[0020] To achieve the above objective, the first invention relates to a floating bag flap gate for preventing flooding of a site due to sudden heavy rain, the floating bag flap gate comprises a gutter or water tank installed around the site to be flooded, an expansion member fixing part continuously installed on the site side of the gutter or water tank, and a long bag-shaped expansion member having an expansion part filled with gas and a base end that is continuously and watertightly fixed to the expansion member fixing part, when rainwater enters the gutter or water tank and the water level rises, buoyancy is generated in the expansion member, and the expansion member rotates and stands upright, causing it to float and form a waterproof wall, the bag structure of the expansion member and the mooring at the expansion member fixing part maintain a high weir height, and when the water level of the incoming rainwater fills the gutter or water tank, the center of gravity of the gas-filled expansion member is located outside the side surface position on the site side of the gutter or water tank, Furthermore, when the water level of incoming rainwater rises above the level of the gutter or water tank, a tensile load is generated at the free base end of the expansion member that is not fixed by the expansion member fixing part. This tensile load generates an elastic restoring force at the free base end, which pulls the expansion member back outwards from the site. When the water level of the rainwater drops to a level that fills the gutter or water tank, the center of gravity of the expansion member is located outside the side surface position of the gutter or water tank within the site, so that the expansion member is automatically retracted into the gutter or water tank without any power.

[0021] According to the above configuration, the floating flap gate does not have a rigid door body like conventional ones, and a lightweight, gas-filled expansion member forms the waterproof wall. Therefore, it does not have a high-rigidity hinge section that requires high workability to support a heavy, rigid door body, nor does it require additional sealing members that require high-precision processing and installation to prevent rainwater leakage at the base. Furthermore, it does not require biasing mechanisms such as counterweights to levitate the heavy, rigid door body. It also does not require stopper members or mooring members that are provided to prevent the heavy, rigid door from falling to the opposite side after it has risen. Moreover, it does not require door stops provided on both the left and right ends of the heavy, rigid door body, nor sealing members provided to prevent rainwater W leakage from the sliding part between the door body and the door stops.

[0022] The second invention is the first invention, wherein the gutter or water tank has a corner that curves in a direction that surrounds at least one location of the site, the expansion member is configured to rotate and stand up at the corner simultaneously with the straight section to continuously form a waterproof wall, and to be automatically stored in the gutter or water tank, the expansion member is joined at the corner with a vulcanized joint or a clamping joint with a long, narrow plate so that the length of one side in the longitudinal direction increases from the base end towards the tip, and the base end is continuously fixed to the expansion member fixing part, straddling the corner.

[0023] According to the above configuration, the expansion member is not subjected to excessive tensile loads when installed in the side ditch or water tank or during the raising and lowering process. Although the expansion portion is compressed during the raising and lowering process until it reaches a fully upright position, the gas at the corners and the expansion member near the tip move from the corners towards the center. As a result, even when the expansion member is fully upright and compressed, there is no reduction in weir height due to bending or large wrinkles at the corners of the expansion member, and the waterproof wall, including the corners, is raised and automatically retracted in a continuous manner.

[0024] The third invention is a configuration in the second invention in which, when the bending angle at the corner on the side of the side ditch or water tank on the site side is α, the joint angle β at the base end side of the clamping joint at the corner of the expansion member is set to be within the range of (360-α) / 2-22.5 ≤ β ≤ (360-α) / 2+22.5.

[0025] If the joint angle β falls below (360 - α) / 2 - 22.5, the tensile load generated in the longitudinal direction during the uprighting of the stored expansion member becomes large, raising concerns about damage due to the stretching of the expansion member. Conversely, if the joint angle β exceeds (360 - α) / 2 + 22.5, although no tensile load is generated during uprighting, the amount of compression near the tip of the expansion member at maximum uprightness becomes too large, raising concerns that wrinkles will form near the tip and a stable weir height cannot be maintained. On the other hand, with the above configuration, uprighting and lowering can be performed without such problems, and the weir height can be maintained during uprighting.

[0026] In the fourth invention, the gutter or water tank has a corner that curves in a direction that surrounds at least one location of the site, and the corner also rotates and stands upright simultaneously with the straight section to continuously form a waterproof wall, and is configured to be automatically stored inside the gutter or water tank, and the end faces of the expandable member that abut in the longitudinal direction and the flexible rubber sheet for corner protection are sandwiched and joined by a plate material.

[0027] According to the above configuration, a flexible rubber sheet at an appropriate angle is connected to the end face of the expansion member that abuts longitudinally across the corner. As a result, the expansion member and the flexible rubber sheet are not subjected to excessive tensile loads when installed in the gutter or water tank or during the undulation process. As the flexible rubber sheet deforms according to the undulation angle during the undulation process to reach the fully upright position, when the two joint plates aligned longitudinally in the fully upright position are standing upright, the expansion member and the flexible rubber sheet at the corner do not experience bending or large wrinkles that reduce the weir height. This allows for the continuous uprighting and automatic retraction of the waterproof wall, including the corner. This makes it possible to install a waterproof wall continuously even at the corners of the site with an extremely simple structure, providing inexpensive protection for the site from rainwater.

[0028] In the fifth invention, in the first invention, the flexible free base end length Lf is 20% to 150% of the shortest winding distance Lmin from the end of the expansion member fixing part to the ground on the side of the ditch or water tank site.

[0029] If the free base length Lf becomes extremely long, exceeding 150% of the shortest winding distance Lmin, the elastic recovery force of the base 11 may be lost, preventing the expansion member from being automatically retracted. Also, if the free base length Lf falls below 20% of the shortest winding distance Lmin, the expansion member may be pulled away from the expansion member fixing part, potentially reducing the upright height of the expansion member. However, with the above configuration, the elastic recovery force of the base can be maintained, allowing the expansion member to be automatically retracted, and preventing a decrease in the upright height of the expansion member.

[0030] In the sixth invention, in the fifth invention, the free base end length Lf is 70% or more and 100% or less of the shortest winding distance Lmin.

[0031] According to the above configuration, stable automatic retraction is possible, and a high weir height can be maintained.

[0032] In the seventh invention, in the fifth or sixth invention, an inclined section is provided on the side of the ditch within the premises, and the free base length Lf is set so that when the water level rises to its maximum and the expansion member is in a fully upright state, the bottom of the expansion member rests on the inclined section, and when the water level drops, the expansion member rolls down the inclined section by its own weight, so that when the rainwater level drops to a level that fills the ditch or water tank, the center of gravity of the expansion member is located outside the side surface position within the premises of the ditch or water tank, and the expansion member is automatically stored in the ditch or water tank without power.

[0033] With the above configuration, in addition to the elastic restoring force of the free base end, the self-weight of the expansion member due to the inclined section can also be utilized, making it easier to automatically retract the expansion member without power.

[0034] In the eighth invention, in any one of the first to seventh inventions, the expansion portion has a hollow structure, and the integrally formed base end has a solid structure, and the base end protrudes from the expansion portion when the expansion portion is filled with gas.

[0035] The above configuration eliminates the risk of gas leakage due to insufficient tightening at the expansion member fixing part, and makes installation easier.

[0036] In the ninth invention, in any one of the first to eighth inventions, the expansion portion has a hollow structure, the integrally formed base end has a solid structure, and it further has an integrally formed solid tip, the tip protrudes from the expansion portion when the expansion portion is filled with gas, and the tip is positioned higher than the expansion portion when the maximum water level is reached.

[0037] According to the above configuration, the maximum weir height is increased, and the increased rigidity of the tip prevents a partial decrease in weir height due to wrinkles or bending in the expanded section.

[0038] In the tenth invention, in any one of the first to ninth inventions, the expansion portion and the base end of the expansion member are made of a seamlessly integrated rubber material.

[0039] According to the above configuration, the base end portion protrudes from the expansion portion, and it is possible to prevent damage to the expansion member without generating excessive shear force at the base end position of the base end portion.

[0040] In the 11th invention, in the 10th invention, the reinforcing cloth is buried over the entire inner circumference of the expansion portion.

[0041] According to the above configuration, it is possible to withstand a higher air pressure.

[0042] In the 12th invention, in the 10th invention, the reinforcing cloth is continuously buried from the expansion portion to the base end portion.

[0043] According to the above configuration, when a higher weir height is required, the total water pressure applied to the expansion member by the invading rainwater becomes very large. Therefore, even when a large tensile load is generated at the base end portion of the expansion member, it is possible to prevent reinforcement of the base end portion and damage at the base of the base end portion. By embedding the reinforcing cloth up to the tip portion, the rigidity of the tip portion is increased, and it is possible to prevent the tip portion from falling and overtopping due to the branches and leaves of the trees flowing together with the rainwater.

[0044] In the 13th invention, in any one of the 1st to 12th inventions, the expansion member has a gas insertion port communicating with the expansion portion, and a hose is connected to the gas insertion port so that gas can be filled.

[0045] According to the above configuration, it is possible to increase the pressure easily and quickly when there is a decrease in gas pressure over time.

[0046] In the 14th invention, in any one of the 1st to 13th inventions, the expansion member is in a single sheet form, and the base end portions corresponding to both ends of the sheet are overlapped and simultaneously tightened and fixed at the expansion member fixing portion to form a hollow expansion portion. By putting a support container for holding gas such as a plurality of foams or hollow frames in the expansion portion, the shape of the expansion portion is maintained, and further, a flat surface by the expansion member is formed on the upper surface of the side groove or the water storage tank.

[0047] According to the above configuration, in the installed state, a flat surface can be formed on the upper surface of the gutter by the expansion member, so that it is possible to effectively prevent people and objects from falling into the gutter.

[0048] In the 15th invention, in the 14th invention, when the expansion member stands up greatly near the maximum water level, a protrusion is provided at the lower part of the expansion member so that the center of gravity of the expansion member does not become inside the inner side surface position of the site of the gutter or the water storage tank, and a stopper is provided on the outer side surface of the site of the gutter or the water storage tank.

[0049] According to the above configuration, by making the protrusion abut against the stopper to stabilize the standing position of the expansion member, when the expansion member stands up greatly near the maximum water level, the center of gravity of the expansion member is kept outside the inner side surface position of the site of the gutter or the water storage tank, so that when the water level of the rainwater drops, the expansion member is automatically and surely stored inside the gutter or the water storage tank without power.

[0050] In the 16th invention, in any one of the 1st to 15th inventions, the expansion member fixing part is provided at the upper part of the inner side surface of the site of the gutter or the water storage tank.

[0051] According to the above configuration, the length of the base end part can be made as short as possible, and it becomes easier to configure the expansion member to be automatically stored in the gutter or the water storage tank without power when the rainwater recedes.

[0052] In the 17th invention, in any one of the 1st to 16th inventions, it has a fulcrum on the ground on the outer side of the site of the gutter or the water storage tank, and is usually provided to cover the gutter or the water storage tank. When the expansion member stands up, it rises, rainwater permeates through and blocks driftwood, and a protection member is provided to prevent the driftwood from colliding with the expansion member. Pushed up by the floating of the expansion member due to the intrusion of rainwater, the protection member stands up to form a protective wall. As the expansion member descends with the drop in the water level, the protection member falls down by its own weight, so that the expansion member and the protection member are configured to automatically return to the original state before the rainwater intrudes without power.

[0053] With the above configuration, under normal circumstances, vehicles and people can pass over the protective member, so the expansion member is less likely to be damaged. When the expansion member expands, it is raised by the expansion member, forming a protective wall that prevents driftwood from hitting the expansion member, and when the water level drops, it returns to its original state without any power. Also, since rainwater can pass through, excessive pressure is not generated on the protective member, and it does not crush the expansion member. Therefore, it can be made lightweight and low cost.

[0054] In the 18th invention, the pivot point position and length of the protective member are set such that when the rainwater reaches the maximum water level and the expansion member is fully upright, the tip position of the protective member exceeds the tangent to the outer circumference of the expansion member.

[0055] With the above configuration, when the water level drops and the expansion member is automatically retracted into the gutter, the tip of the protective member does not get caught on the expansion member, and the protective member can also be closed automatically without any power.

[0056] In the 19th invention, in the 17th or 18th invention, the protective member is a grating made of a lightweight material such as wood or resin.

[0057] With the above configuration, the protective member is lightweight and floats on water, so it does not resist the expansion member, and the protective member can be easily erected. In addition, if it is made of wood, it has an excellent appearance when used as a cover for a drainage ditch in normal conditions, and because it is a biomass material, CO2 ２ This will also lead to reductions.

[0058] In the 20th invention, in the first or 17th invention, a metal cover having a pivot point on the outside of the drainage ditch is attached to the vehicle passage section crossing the drainage ditch or water tank, and a biasing means such as a counterweight or hydraulic cylinder is provided to assist in lifting upward the area near the tip of the metal cover on the inside of the drainage ditch when the expansion member is erected.

[0059] With the above configuration, under normal circumstances, the highly rigid metal cover allows even extra-large vehicles to pass through. On the other hand, the metal cover can be removed in advance when there is a risk of flooding, but while it is highly rigid, it is also heavy, requiring heavy machinery, personnel, and time. By providing a biasing means such as a counterweight or hydraulic cylinder to assist in raising the metal cover, which can be opened and closed when the expansion member is raised, the cover can be easily opened and closed when the expansion member is raised or lowered.

[0060] In the 21st invention, as in the 20th invention, the metal cover is permeable to rainwater such as grating, and is configured to block large driftwood as a protective member when it rises, thereby preventing large driftwood from colliding with the expansion member.

[0061] According to the above configuration, when the metal cover rises, it can act as a protective element, blocking large pieces of driftwood and preventing them from colliding with the expansion element.

[0062] The 22nd invention relates to a waterproofing method using a floating bag flap gate to prevent flooding of a site due to sudden heavy rain, and the waterproofing method provides a side ditch or water tank installed around the site to be flooded, an expansion member fixing part installed continuously on the site side of the side ditch or water tank, and a floating bag flap gate composed of an expansion member having an expansion part filled with gas and a base end that is continuously and watertightly fixed to the expansion member fixing part, and when rainwater enters the side ditch or water tank and the water level rises, buoyancy is generated in the expansion member, and the expansion member rotates and stands upright, so as to float and form a waterproof wall, and when the water level of the invading rainwater fills the side ditch or water tank, the center of gravity of the gas-filled expansion member is located outside the side surface position on the site side of the side ditch or water tank. Furthermore, when the water level of incoming rainwater rises above the level of the gutter or water tank, a tensile load is generated at the free base end of the expansion member that is not fixed by the expansion member fixing part. This tensile load generates an elastic restoring force at the free base end, which pulls the expansion member back outwards from the site. When the water level of the rainwater drops to a level that fills the gutter or water tank, the center of gravity of the expansion member is located outside the side surface position of the gutter or water tank within the site, thereby automatically retracting the expansion member into the gutter or water tank without any power.

[0063] In the 23rd invention, in the 22nd invention, the floating bag flap gate is further provided with a protective member that has a fulcrum on the ground outside the site of the side ditch or water tank, is normally installed to cover the side ditch or water tank, stands up when the expansion member is erected, allows rainwater to pass through but blocks driftwood, and prevents driftwood from colliding with the expansion member. The protective member is pushed up by the rise of the expansion member as rainwater enters, causing it to stand up and form a protective wall, and as the expansion member descends as the water level drops, the protective member collapses under its own weight, so that the expansion member and the protective member automatically return to their original state before rainwater entered without any power.

[0064] As described above, the present invention provides a bag-type flap gate that is extremely simple, low-cost, and highly reliable compared to conventional floating bag-type flap gates.

[0065] This is a cross-sectional view showing the floating bag flap gate and its surroundings in an installed state according to Embodiment 1 of the present invention. This is a cross-sectional view showing the floating bag flap gate and its surroundings in a state of rainwater immersion in a side ditch according to Embodiment 1 of the present invention. This is a cross-sectional view showing the center of gravity of the expansion member in a side ditch full of water according to Embodiment 1 of the present invention. This is a cross-sectional view showing the center of gravity of the expansion member in a fully upright state according to Embodiment 1 of the present invention. This is a perspective view showing the expansion member at a side ditch corner according to a modified corner 1. This is a perspective view showing the floating bag flap gate and its surroundings in an installed state at a side ditch corner according to a modified corner 1. This is a perspective view showing the floating bag flap gate and its surroundings in a fully upright state at a side ditch corner according to a modified corner 1. This is a perspective view showing the expansion member at a side ditch corner according to a modified corner 2. This is a perspective view showing the floating bag flap gate and its surroundings in an installed state at a side ditch corner according to a modified corner 2. This is a perspective view showing the floating bag flap gate and its surroundings in a fully upright state at a side ditch corner according to a modified corner 2. This is a perspective view showing the expansion member at the corner of a side ditch, according to Modification 3 of the corner. This is a perspective view showing the floating bag flap gate and its surroundings in an installed state at the corner of a side ditch, according to Modification 3 of the corner. This is a perspective view showing the floating bag flap gate and its surroundings in a fully upright state at the corner of a side ditch, according to Modification 3 of the corner. This is a cross-sectional view illustrating the relationship between the free base length and the shortest winding distance according to Embodiment 1 of the present invention. This is a cross-sectional view showing the floating bag flap gate and its surroundings in an installed state, according to Modification 1 of the side surface within the site of a side ditch. This is a cross-sectional view showing the center of gravity of the expansion member in a fully upright state, according to Modification 1 of the side surface within the site of a side ditch. This is a cross-sectional view showing the floating bag flap gate and its surroundings in an installed state, according to Modification 2 of the side surface within the site of a side ditch. This is a cross-sectional view showing the center of gravity of the expansion member in a fully upright state, according to Modification 2 of the side surface within the site of a side ditch. This is a perspective view showing the cross section of the expansion member in a folded state. This is a perspective view showing the cross section of the expansion member in a gas-filled state. This is a perspective view showing the cross section of the expansion member in a folded state, according to Modification 1 of the expansion member. This is a perspective view showing a cross-section of an expansion member in a gas-filled state, according to Modification 1 of the expansion member.This is a cross-sectional view showing an inflatable member in a fully upright state according to Modification 1 of the inflatable member. This is a cross-sectional view showing an inflatable member made of a single rubber material according to Modification 1 of the inflatable member. This is a cross-sectional view showing an inflatable member having one layer of reinforcing fabric in the inflatable portion according to Modification 2 of the inflatable member. This is a cross-sectional view showing an inflatable member having two layers of reinforcing fabric in the inflatable portion according to Modification 3 of the inflatable member. This is a cross-sectional view showing an inflatable member having reinforcing fabric from a part of the inflatable portion to the base end according to Modification 4 of the inflatable member. This is a cross-sectional view showing an inflatable member having reinforcing fabric continuously from the base end to the tip according to Modification 5 of the inflatable member. This is a cross-sectional view showing a means for filling the inflatable member with gas according to Modification 6 of the inflatable member. This is a cross-sectional view corresponding to Figure 1A showing the installed state of an inflatable member containing foam or a hollow frame according to Embodiment 2 of the present invention. This is a cross-sectional view corresponding to Figure 1D showing the fully upright state of an inflatable member containing foam or a hollow frame according to Embodiment 2 of the present invention. This is a cross-sectional view showing the installed state of an inflatable member containing foam or a hollow frame with protrusions according to Embodiment 3 of the present invention. This is a cross-sectional view showing the fully upright state of an inflatable member containing a foam or hollow frame with a projection having a protective member, according to Embodiment 3 of the present invention. This is a cross-sectional view showing the installed state of a floating bag flap gate, according to Embodiment 4 of the present invention. This is a cross-sectional view showing the fully upright state of a floating bag flap gate, according to Embodiment 4 of the present invention. This is a cross-sectional view showing the length of the protective member in the fully upright state of the floating bag flap gate, according to Embodiment 4 of the present invention. This is a perspective view showing the vehicle passage portion of a floating bag flap gate, according to Embodiment 5 of the present invention. This is a cross-sectional view showing the vehicle passage portion of a floating bag flap gate in an installed state, according to Embodiment 5 of the present invention. This is a cross-sectional view showing the vehicle passage portion of a floating bag flap gate in a state where the side ditch is full of water, according to Embodiment 5 of the present invention. This is a cross-sectional view showing the vehicle passage portion of a floating bag flap gate in a fully upright state, according to Embodiment 5 of the present invention.

[0066] Embodiments of the present invention will be described below with reference to the drawings.

[0067] (Embodiment 1) -Configuration of a floating bag flap gate- Figures 1A, 1B, 1C, and 1D show a floating bag flap gate 1 according to an embodiment of the present invention. This floating bag flap gate 1 comprises a side ditch 2 or water tank installed around the perimeter of a site to prevent flooding, an expansion member fixing part 3 continuously installed on the site side S1 of the side ditch 2 or water tank, and a long bag-shaped expansion member 10 having an airtight expansion part 12 filled with gas A and a base end 11 that is continuously and watertightly fixed to the expansion member fixing part 3.

[0068] The size of the drainage ditch 2 or water storage tank installed around the site is set appropriately depending on the size of the facility and the risk of land flooding, such as 1m wide x 1m deep or 2m wide x 2m deep. The drainage ditch 2 or water storage tank is usually made of concrete walls.

[0069] In low-lying areas where the entire site is at risk of flooding, drainage ditches 2 or water tanks are installed to surround the entire perimeter of the site. However, if a portion of the site is elevated and therefore at low risk of flooding, it is not necessary to surround the entire site; installation should be limited to the necessary area around the perimeter of the site. Figure 1A, etc., illustrates building B, which is protected from flooding.

[0070] As shown in an enlarged view in Figure 5, the expansion member fixing part 3 is configured such that the expansion member 10 is sandwiched between metal plates and tightened with bolts, etc. One of the metal plates 3c is embedded in the side wall concrete with the anchor bolt 3a protruding. The separate metal plate 3d has multiple through holes drilled at equal pitch to the anchor bolt 3a and is a metal plate about 1 m long. The metal plate 3c embedded in the side wall concrete and the separate metal plate 3d have interlocking surfaces, and by sandwiching the expansion member 10 and tightening it with bolts and / or nuts 3b, the expansion member 10 can be firmly fixed and sealed.

[0071] The expansion member fixing part 3 is installed continuously on the side S1 of the side ditch 2 or water storage tank. It is usually installed on the upper part of the side wall of the side ditch 2, but it may also be installed on the ground near the side wall.

[0072] In Figure 1A, the expansion member fixing part 3 is provided on the upper part of the side surface S1 on the side of the ditch 2 or water tank site. As a result, the expansion member 10 can be efficiently raised and lowered at its short base end 11 by rotating approximately with the expansion member fixing part 3 as the pivot point.

[0073] On the other hand, as shown in Figure 8A, the pre-formed bag-shaped expansion member 10 has a hollow expansion portion 12 and a solid base portion 11, and the base portion 11 is fixed to the expansion member fixing portion 3 and tightened.

[0074] In either case, through holes (not shown) are made in the base end portion 11 at the same pitch as the anchor bolts 3a of the expansion member fixing portion 3. The through holes of the expansion member 10 are passed through the anchor bolts 3a, and a separate metal plate 3d is fitted onto them and tightened with nuts 3b. The separate metal plates 3d are installed continuously with almost no gaps.

[0075] The expansion member 10 is usually manufactured in a length of 100 to 200 m, but if the length of the perimeter of the site S to be enclosed exceeds that, it is advisable to use vulcanization joints or metal joints to create an endless joint.

[0076] If the gutter 2 or water tank is installed to cover the entire site S, it will form an endless bag-like structure joined to the expansion member 10 without any end faces. However, if the gutter 2 or water tank does not cover the entire perimeter, such as when part of the site S is higher, as described above, it is advisable to also install the expansion member fixing part 3 on the wall at the end of the gutter 2 or water tank, and fix the end faces of the bag-like structure in the same manner to ensure airtightness.

[0077] The height at which the expansion member fixing part 3 is installed on the wall at the end can be selected based on the installation constraints.

[0078] The expansion member 10 is usually a long rubber bag, and there are two types: one that is a flat sheet before being attached to the expansion member fixing part 3, and one that is already in a bag shape.

[0079] Rubber material is ideal as the material for the expansion member 10 because it possesses flexibility, airtightness, watertightness, and strength. While ethylene-propylene rubber is the most preferred rubber material due to its balance of weather resistance, heat resistance, abrasion resistance, flexibility, strength, fatigue resistance, airtightness, watertightness, and price, other synthetic rubbers and natural rubbers can also be used.

[0080] In the case of a flat sheet, the ends of the sheet are folded back and overlapped, and the overlapped portions at both ends (base ends 11) are sandwiched in the expansion member fixing portion 3 and tightened to form a long bag shape. The portion sandwiched in the expansion member fixing portion 3 is the base end 11, and the remaining bag-shaped portion filled with gas A is the expansion portion 12.

[0081] In any case, the floating bag flap gate 1 using a long bag body can utilize the elasticity of rubber, so there is no sliding with the door stopper like in conventional flap gates, and no special sealing structure is required, making it simple and highly reliable.

[0082] As shown in Figures 1B and 1C, the floating bag flap gate 1 is configured such that when rainwater enters the side ditch 2 or water tank and the water level H rises, buoyancy is generated in the lightweight inflatable member 10, and the inflatable member 10 rotates and stands upright with the inflatable member fixing part 3 as a fulcrum, easily floating up and forming a waterproof wall. The bag structure of the inflatable member 10 and its mooring at the inflatable member fixing part 3 maintain a high weir height. Although not shown in detail, guide grooves or guide holes communicating with the side ditch 2 may be provided on the upper end of the side surface S2 outside the site of the side ditch 2 to facilitate the flow of rainwater W into the bottom surface of the side ditch 2.

[0083] Furthermore, as shown in Figure 1C, when the water level H of the incoming rainwater W fills the gutter 2 or the water storage tank, the center of gravity O of the gas-filled expansion member 10 is located above the gutter 2.

[0084] Furthermore, as shown in Figure 1D, when the water level H of the incoming rainwater W rises above the level of the gutter 2 or the water tank, a tensile load is generated at the free base end 11a of the base end 11 of the expansion member 10 that is not fixed by the expansion member fixing part 3. At this time, the center of gravity O of the expansion member 10 may be located inside (towards the building B) of the inner side surface position S of the site of the gutter 2 or the water tank. Due to the elastic restoring force generated at the free base end 11a caused by the tensile load, when the water level H of the rainwater W drops to the level that fills the gutter 2 or the water tank, the expansion member 10 is pulled back in the direction S2 outside the site, and the center of gravity O of the expansion member 10 is located outside the side surface position S1 inside the site of the gutter 2 or the water tank, so that the expansion member 10 is automatically stored in the gutter 2 or the water tank without power.

[0085] - How to use the floating bag flap gate - The changes in state will be explained below with reference to Figures 1A, 1B, 1C, and 1D.

[0086] First, in the installed state, as shown in Figure 1A, the expansion member 10 is housed inside the gutter 2. In this embodiment, the curved upper surface of the expansion portion 12 may be exposed on the upper side of the gutter 2.

[0087] As rainwater W gradually enters the gutter 2, buoyancy is generated in the expansion member 10, as shown in Figure 1B, causing it to float upwards. The expansion member 10 rotates and stands upright with the expansion member fixing part 3 as the pivot point. As described above, the rainwater W may be directed downwards to the expansion part 12 through guide grooves or guide holes (not shown).

[0088] The inflow of rainwater W into the side ditch 2 increases when the amount of rainwater W increases and the drainage capacity is insufficient. In the case of a side ditch 2 with a drainage channel, it is advisable to adjust the drainage rate so that the water level H naturally decreases as the amount of rainwater W decreases. On the other hand, in the case of a side ditch 2 without a drainage channel, it is advisable to install a drain plug or the like in advance to discharge the rainwater W from the side ditch 2 when the amount of rainwater W decreases.

[0089] Furthermore, utilizing side ditch 2 as a water storage tank would allow for the temporary storage of rainwater W during heavy rains, thus helping to prevent inland flooding caused by rising water levels in rainwater pipes and irrigation canals, making it even more effective.

[0090] When the water level H of the incoming rainwater W fills the gutter 2 or the water storage tank, as shown in Figure 1C, the center of gravity O of the expansion member 10 filled with gas A is located outside (on the gutter 2) by a distance (X1) from the side surface S1 on the site side of the gutter 2 or the water storage tank.

[0091] Furthermore, when the water level H rises to near the maximum water level, as shown in Figure 1D, the expansion member 10 stands completely upright, forming a waterproof wall, and a very large total water pressure is generated on the side surface of the expansion member 10. At this time, due to the water pressure, the center of gravity O of the expansion member 10 filled with gas A may be located a distance (X2) inward from the side surface S1 on the premises side of the side ditch 2 or the water storage tank. However, it is desirable that the distance (X2) is not too large.

[0092] The large water pressure on the side wall of the expansion member 10 generates a large tensile load on the free base end 11a of the expansion member 10 to prevent it from rolling in the direction S1 towards the site. Here, since the expansion member 10 is made of an elastic material, the tensile load generated by the water pressure becomes an elastic restoring force that pulls the expansion member 10 back in the direction S2 towards the outside of the site.

[0093] Next, as the water level H decreases from the maximum water level H, the total water pressure of the rainwater W decreases, and the expansion member 10 is pulled back in the direction S2 outwards from the site by the elastic restoring force of the free base end 11a.

[0094] Furthermore, when the water level H drops further and fills the side ditch 2 or the water tank, the center of gravity O of the expansion member 10 is configured to be located at a distance (X1) outside the lateral position S1 on the side of the side ditch 2 or the water tank on the site side.

[0095] As a result, the expansion member 10 is automatically retracted into the side ditch 2 or water tank without the need for power, returning to the installed state shown in Figure 1A.

[0096] Although not shown in detail in the diagram, if the side ditch 2 is to be used as a water storage tank, it is advisable to install both a normal piping route for discharging rainwater W from inside the facility into a rainwater pipe or irrigation channel, and a piping route for storing it in the water storage tank, so that the route can be changed depending on the situation. It is also advisable to install a drain plug to discharge the rainwater W stored in the water storage tank into a rainwater pipe or irrigation channel.

[0097] It is desirable to pre-fill the bag of the expansion member 10 with a gas A such as air. If gas A is filled after the risk of flooding arises, it will take time to pump the air in with a pump (not shown), making it impossible to respond to sudden heavy rainfall.

[0098] Therefore, it is desirable to keep the container filled with air as much as possible under normal circumstances, and to add more air (which can be filled in a short time) as needed using a pump, compressor, etc. (not shown) when there is a risk of flooding. A mechanism to maintain the required level of pressure of gas A at all times may also be installed.

[0099] -Effects- As described above, in this embodiment, when external or internal flooding actually occurs and rainwater W accumulates in the side ditch 2 or water tank, the buoyancy of the water causes the expansion member 10 to gradually stand up. Unlike conventional rigid metal door bodies, the expansion member 10 is very light and has no sliding resistance with the hinge or door stopper, so it can be easily stood up without a biasing mechanism.

[0100] Furthermore, as the water level H rises and reaches near the maximum water level H, the water pressure of the rainwater W causes the expansion member 10 to experience significant pressure on the site side S1, attempting to roll. However, the tensile load at the base end 11 of the expansion member 10 absorbs this pressure, maintaining a stable water level H. Therefore, stopper members and mooring members like those found in conventional flap gates are not required.

[0101] On the other hand, as the water level H decreases, the expansion member 10 returns to the side ditch 2 side in the direction of the outside of the site S2 due to the elastic restoring force of the free base end 11a of the expansion member 10, which is made of an elastic material, as the pressure acting on the expansion member 10 decreases.

[0102] In this embodiment, when the water level H is near the full capacity of the side ditch 2 or the reservoir, the center of gravity O of the expansion member 10 is on the side ditch 2 side. As the water level H further decreases, the expansion member 10 is retracted to its original position by its own weight, forming a waterproof wall automatically and without power during flooding without human intervention, and returning to its original state automatically and without power when the flooding subsides.

[0103] Thus, the floating bag flap gate 1 according to the present invention does not have a rigid door body like conventional floating flap gates, and a lightweight expanding member 10 filled with gas A forms a waterproof wall. Therefore, it does not have a highly rigid hinge section that requires high workability to support a heavy rigid door body, nor does it require an additional sealing member that requires high-precision processing and installation to prevent rainwater W leakage at the rubber hinge section.

[0104] Furthermore, there is no need for biasing mechanisms such as counterweights to levitate the heavy, rigid door body.

[0105] Furthermore, there is no need for stopper or tethering members to prevent the heavy, rigid door from falling over to the other side after it has been raised.

[0106] Furthermore, it eliminates the need for door stops provided on both the left and right ends of the heavy, rigid door body, as well as sealing members provided to prevent rainwater W from leaking from the sliding parts between the door body and the door stops.

[0107] As described above, the floating bag flap gate 1 of the present invention does not require any of the rigid door body, high-rigidity hinge section, additional sealing member for the hinge section, biasing mechanism, mooring member, door stopper, and side sealing members that were necessary for conventional floating flap gates. It consists only of an extremely simple and lightweight expansion member 10, making it low-cost and highly reliable.

[0108] In this embodiment, when the water level H of the incoming rainwater W exceeds the gutter 2 or the water storage tank, the center of gravity O of the gas-filled expansion member 10 is located outside the side surface S1 on the premises side of the gutter 2 or the water storage tank. As shown in Figure 5, the length Lf of the flexible free base end is set to be at the same level as or slightly shorter (for example, 20% to 150%) than the shortest winding distance Lmin from the end of the expansion member fixing part 3 (the beginning of the free base end 11a) to the upper end (ground level) of the side surface S1 on the premises side of the gutter 2 or the water storage tank. When the tank is full, the free base end 11a experiences the maximum tensile load and winds with high surface pressure along the minimum winding distance Lmin. Therefore, to prevent breakage of the free base end 11a, it is important that there are no sharp parts within the winding range. Therefore, when the free base end portion 11a wraps around the metal plate 3d of the expansion member fixing portion 3 or the corner of the upper end of the side ditch 2, the corner is rounded or chamfered.

[0109] As the water level H decreases, the total water pressure generated on the side wall of the expansion member 10 decreases, and when it falls below the full water level of the side ditch 2, the total water pressure in the lateral direction disappears. Therefore, if the free base end length Lf becomes longer than the shortest winding distance Lmin (for example, exceeding 150%), the elastic recovery force of the base end 11 disappears at this point. At the point when this elastic recovery force disappears, the center of gravity O of the expansion member 10 may not be outside the side surface S1 on the side ditch 2 side, and the expansion member 10 may not be able to be automatically retracted. For this reason, it is not desirable to set the free base end length Lf to be extremely long relative to the shortest winding distance Lmin.

[0110] On the other hand, if the free base length Lf is extremely short compared to the shortest winding distance Lmin (for example, less than 20%), there is a problem in that the expansion member 10 is pulled away from the expansion member fixing part 3, resulting in a lower upright height of the expansion member 10.

[0111] Therefore, it is desirable that the free base length Lf is not extremely short compared to the shortest wrapping distance Lmin.

[0112] The free base end length Lf is preferably set to 20% to 150% of the shortest winding distance Lmin, more preferably 70% to 100%, so that it can be reliably automatically retracted and a high weir height can be maintained.

[0113] -Corner Modification 1- However, conventional floating flap gates use a rigid door body, making it impossible to install a waterproof door at the corner 620 of a facility site. To partially solve this problem, as described in Japanese Patent Publication No. 669668, a floating flap gate has been proposed in which a corner flap gate is installed at the corner 620 by combining multiple door bodies, and the corner door bodies, connected by a hinge structure, fold in the upright direction of the door bodies and float when water enters. However, this requires a more complex hinge and sealing structure than conventional floating flap gates, and in order to ensure long-term reliability as a waterproof device, extremely high processing precision is required, resulting in an extremely costly waterproof device.

[0114] In the modified corner 1, as shown in Figures 2A to 2C, the expansion member 610 housed in the corner 620 of the side ditch 2 or water tank is joined at the corner by a vulcanization joint 616 such that the length of one side in the longitudinal direction increases from the base end 611 towards the tip end 613.

[0115] The vulcanized joint 616 shown in Figure 2A is a joint method in which a sheet of unvulcanized rubber or adhesive rubber is attached between two vulcanized expandable members 610, and the joint is bonded by applying heat and pressure to the joint using the cross-linking reaction of the unvulcanized rubber while sandwiching it with a small vulcanizing press. More preferably, the bonding surface is buffed and roughened in advance, adhesive rubber dissolved in a solvent is applied, and then the unvulcanized rubber sheet is attached and heat pressing is performed.

[0116] To ensure higher adhesive strength, the joint positions of the laminated reinforcing fabrics (not shown) are staggered, and sheet-like unvulcanized rubber is embedded between each reinforcing fabric and vulcanized, or additional reinforcing fabric is embedded to reinforce the joint.

[0117] As shown in Figure 2B, the expanded member 610, which is joined in this manner, has its base end 611 continuously fixed to the expanded member fixing part 3, straddling the corner 620 of the side ditch 2 or water tank 620.

[0118] With this configuration, the vulcanization joint 616 is used to join the expansion member 610 so that the length of one side in the longitudinal direction increases from the base end 611 towards the tip end 613, and the base end 611 is continuously fixed to the expansion member fixing part 3 across the corner 620. As a result, the expansion member 610 can undulate without being subjected to excessive tensile loads when installed in the side ditch 2 or water tank, or during the undulation process.

[0119] Furthermore, although the expansion section 612 is compressed during the process of rising and falling to a fully upright position, the gas in the corner section 620 and the expansion member 610 near the tip move from the corner section 620 towards the central position. As shown in Figure 2C, even when the expansion member 610 is compressed in the fully upright position, the continuous raising and automatic retraction of the waterproof wall, including the corner section 620, does not occur due to bending or large wrinkles causing a decrease in the weir height.

[0120] -Modification of corner section 2- In modification of corner section 2, as shown in Figures 3A to 3C, the expansion member 610' housed in the corner section 620 of the side ditch 2 or water tank is joined at the corner section by a long, narrow plate 617 such that the length of one side in the longitudinal direction increases from the base end 611 towards the tip end 613.

[0121] The clamping joint using the elongated plate material 617 shown in Figure 3A clamps the joint portion of the expansion member 610', which is normally butted longitudinally between two metal plates, in one go, and tightens with a bolt 618. This ensures that the strong joint of the expansion member 610' and the sealing of the expansion portion 612 are achieved simultaneously.

[0122] Although not shown in detail, if necessary, a conductive pipe may be embedded between the two elongated plates 617 to provide electrical conductivity to the expanded portion 612 of the expanded member 610' which is abutted in the longitudinal direction.

[0123] Since the base end 611 requires a degree of freedom when the expansion member is erected or collapsed, it is not clamped with a long, narrow plate 617, but a waterproof sheet is attached to prevent rainwater leakage.

[0124] As shown in Figure 3B, the jointed expansion member 610' has its base end 611 continuously fixed to the expansion member fixing part 3 at the corner 620 of the side ditch 2 or water tank.

[0125] With this configuration, a clamping joint is made with a long, narrow plate 617 such that the length of one side in the longitudinal direction increases from the base end 611 towards the tip end 613, and the base end 611 is continuously fixed to the expansion member fixing part 3 across the corner 620. As a result, the expansion member 610' can undulate without being subjected to excessive tensile loads when installed in the side ditch 2 or water tank and during the undulation process.

[0126] Furthermore, although the expansion section 612 is compressed during the process of rising and falling to a fully upright position, the gas in the corner section 620 and the expansion member 610' near the tip move from the corner section 620 towards the central position. As shown in Figure 3C, even when the expansion member 610' is compressed in the fully upright position, the continuous raising and automatic retraction of the waterproof wall, including the corner section 620, does not occur due to bending or large wrinkles causing a decrease in the weir height.

[0127] -Numerical limitations in modified corners 1 and 2- When the bending angle on the side of the side ditch 2 or water tank on the interior side of the corner 620 is α, the joint angle β at the base end side of the vulcanization joint 616 or the clamping joint of the elongated plate material 617 at the corner 620 of the expansion members 610, 610' is set within the range of the following formula.

[0128] (360-α) / 2-22.5 ≤ β ≤ (360-α) / 2+22.5 ... (1) If the joint angle β falls below (360-α) / 2-22.5, the tensile load generated in the longitudinal direction as the stored expansion members 610, 610' stand up will increase, raising concerns about damage to the expansion members 610, 610' due to elongation.

[0129] Furthermore, if the joint angle β exceeds (360 - α) / 2 + 22.5, although no tensile load will be generated when the structure is upright, there is a concern that the amount of compression near the tips of the expansion members 610, 610' at maximum upright position will become too large, causing wrinkles to form near the tips and making it impossible to maintain a stable weir height.

[0130] On the other hand, if the range of the joint angle is within the range of equation (1), the weir can be erected and lowered without any problems, and the weir height can be maintained when erected.

[0131] For example, if the bending angle α on the side of the ditch 2 or water tank on the premises side at corner 620 is 90°, the appropriate joint angle is 112.5 ≤ β ≤ 157.5.

[0132] -Corner Modification 3- In this modification, as shown in Figure 4A, the expansion member 610'' that abuts in the longitudinal direction at the corner 620 is cut at approximately 90° and is sandwiched and joined with the end face of the flexible rubber sheet 619'' for corner protection that abuts in the longitudinal direction.

[0133] The expansion member 610'', which is butted against the corner length in the lateral direction, is cut at γ = approximately 90° and joined to the flexible rubber sheet 619'' by the joint plate 617''. However, since the base end 611 is positioned by the expansion member fixing part 3, when gas is filled and the expansion part 612 inflates, the tip of the joint plate tilts slightly towards the expansion member. Therefore, it is preferable to set the cut angle γ to be somewhat larger than 90° (for example, γ = 110°) so that the joint plate 617'' stands vertically when fully upright. Also, the angle ε of the corner portion of the flexible rubber sheet 619'' is preferably approximately 90°, but it is preferable to set it to be somewhat larger than 90° (for example, ε = 120°) so that it does not receive a large tensile load when standing up. Note that if the cut angle γ of the expansion member 610'' is set to, for example, γ = 100° as described above, there is no problem when standing up, so the angle ε of the flexible rubber sheet 619'' can be ε = 90°.

[0134] The flexible rubber sheet 619'' is preferably fan-shaped when flat, so that its height is uniform when the expansion member 610'' is fully upright. Furthermore, it is preferable to design the shape so that the maximum water level does not decrease when the expansion member 610'' is fully upright.

[0135] When the expansion member 610'' is in its maximum upright position, the lateral load due to water pressure is borne by the entire expansion member 610'' which is butted in the longitudinal direction. Therefore, a large load is not placed on the flexible rubber sheet 619''. However, in order to maintain a stable deformation state, it is preferable to use a rubber sheet with a certain degree of bending rigidity. The hardness and thickness of the rubber sheet to provide rigidity can be set as appropriate.

[0136] The joint plate 617'' simultaneously sandwiches the expansion member 610'' and the flexible rubber sheet 619'' and fastens them with bolts 618 or the like. Through holes (not shown) for the bolts 618 are pre-drilled in the expansion member 610'' and the flexible rubber sheet 619''.

[0137] This ensures that the airtightness of the expansion section 612 is maintained, and that the expansion member 610'' and the flexible rubber sheet 619'' are firmly connected without separating.

[0138] The joint plate 617'' covers and sandwiches up to the expansion portion 612. The base end portion 611 is tightened together with the flexible rubber sheet 619'' at the expansion member fixing portion 3, so there are no strength issues. However, there is a risk of water leakage between the base end portion 611 and the flexible rubber sheet 619'', so if necessary, a water-stopping sheet 621'' can be attached across the base end portion 611 and the flexible rubber sheet 619'' using room-temperature adhesive or the like.

[0139] As shown in Figure 4B, the jointed expansion member 610'' and flexible rubber sheet 619'' are continuously fixed to the expansion member fixing part 3 at the corner 620 of the side ditch 2 or water tank, with the base end 611 spanning the corner 620. In the installed state, the flexible rubber sheet 619'' at the corner 620 is bent in the compression direction. A water-stopping sheet 621'' is attached to the corner of the base end 611 as needed.

[0140] With this configuration, the flexible rubber sheet 619'' can undulate without being subjected to excessive tensile load during the undulation process.

[0141] Furthermore, the end faces of the expansion members 610'' that abut in the longitudinal direction and the flexible rubber sheet for corner protection are sandwiched and joined by a plate material, and the flexible rubber sheet 619'' at an appropriate angle (for example, 110°) is connected to the end face of the expansion member 610'' that abuts in the longitudinal direction across the corner 620, so that the expansion member 610'' and the flexible rubber sheet 619'' are not subjected to excessive tensile loads when installed in the side ditch 2 or water tank or during the undulation process.

[0142] Furthermore, as the flexible rubber sheet 619'' deforms according to the undulation angle during the process of raising and lowering to the fully upright position, as shown in Figure 4C, when the two joint plates 617'' aligned longitudinally in the fully upright position are standing upright, the expansion member 610'' and the flexible rubber sheet 619'' at the corner 620 do not experience any bending or large wrinkles that reduce the weir height, and the continuous waterproof wall including the corner 620 is raised and automatically retracted.

[0143] Furthermore, by making the corner portion 620 a separate flexible rubber sheet 619'', the corner portion of the expansion member 610'', which is particularly susceptible to large strains and quick damage, only needs to be replaced by replacing the flexible rubber sheet 619''. This makes repairs easier when deterioration occurs over time and leads to a reduction in maintenance costs.

[0144] The flexible rubber sheet 619'' may be flat, but it may also be a sheet that has been pre-processed into a bellows shape. When using a rubber sheet that has been processed into a bellows shape, it is more preferable to set the angle ε of the flexible rubber sheet 619'' to be somewhat smaller than 90 degrees (for example, ε = 60°). Because elongation can be expected due to the bellows structure, even if the angle ε of the rubber sheet is somewhat smaller than 90°, the bellows will not open when the surface is uneven and will not be subjected to a large tensile load, and in the fully upright position, the bellows in the portion sandwiched between the two joint plates 617'' arranged in the longitudinal direction will close, effectively forming a waterproof wall.

[0145] With the above configuration, the waterproof wall is formed continuously at corners by rotating and rising simultaneously with the straight sections. Furthermore, it is possible to install a continuous waterproof wall with an extremely simple structure, and it becomes a waterproofing device that is automatically housed in a side ditch or water tank, thus protecting the site from rainwater at low cost.

[0146] - Modified example 1 of the side surface of the drainage ditch on the site - In this modified example, as shown in Figures 6A and 6B, a sloping section S3 is provided by chamfering the side surface of the drainage ditch on the site.

[0147] As shown in Figure 6B, the free base length Lf is set so that when the expansion member 10 is fully upright after the rainwater has risen to its maximum water level, the bottom of the expansion member 10 rests on the inclined portion S3.

[0148] As a result, when the water level drops, the expansion member 10 rolls down the inclined section S3 under its own weight, and when the rainwater level drops to a level that fills the gutter 2 or the water storage tank, the center of gravity of the expansion member 10 is located outside the side surface position within the site of the gutter 2 or the water storage tank, so that the expansion member 10 is automatically stored inside the gutter 2 or the water storage tank without any power.

[0149] In this modified example, in addition to the elastic restoring force of the free base end, the self-weight of the expansion member due to the inclined portion can also be utilized, making it easier to automatically retract the expansion member without power.

[0150] - Modified form 2 of the side surface of the side ditch within the site - In this modified form, as shown in Figures 7A and 7B, an expansion member fixing part 3' may be provided at the upper end of the side ditch 2, and an inclined part S3 may be attached to the upper surface of the expansion member fixing part 3'.

[0151] As shown in Figure 7B, the free base length Lf is set so that when the expansion member 10 is fully upright when the rainwater rises to the maximum water level, the bottom of the expansion member 10 rests on the inclined portion S3. This provides the same effects as in the modified example 1 for the side surface of the side ditch within the site.

[0152] -Structure of the expansion member- In the expansion member 10 of Embodiment 1, as shown in Figure 8A, the expansion portion 12 has a hollow structure, and the integrally formed base end portion 11 has a solid structure. Then, as shown in Figure 8B, when the expansion portion 12 is filled with gas A, the base end portion 11 protrudes from the expansion portion 12.

[0153] This eliminates the risk of gas A leaking due to insufficient tightening at the expansion member fixing part 3, and makes installation easier.

[0154] - Modification 1 of the expansion member - Figures 9A to 9C and 10 show modification 1 of the expansion member of Embodiment 1 of the present invention, which differs from Embodiment 1 in that the expansion member 110 has a tip portion 113. In the following modifications and embodiments, the same reference numerals are used for the same parts as in Figures 1A to 8B, and their detailed descriptions are omitted.

[0155] As shown in Figure 9A, the expansion member 110 has a hollow structure for the expansion portion 12, a solid structure for the integrally formed base end portion 11, and a solid tip portion 113 that is further integrally formed.

[0156] In this case, as shown in Figure 9B, with the expansion section 12 filled with gas A, the base end 11 protrudes from the expansion section 12, and the tip end 113 also protrudes from the expansion section 12.

[0157] As a result, as shown in Figure 9C, when the maximum water level H is reached, the tip portion 113 is positioned higher than the expansion portion 12, thereby increasing the maximum weir height, and the increased rigidity of the tip portion 113 prevents a partial decrease in weir height due to wrinkles or bending of the expansion portion 12.

[0158] Furthermore, as shown in an enlarged view in Figure 10, in Modification 1, the expansion portion 12, base portion 11, and tip portion 113 of the expansion member 110 are made of a seamlessly integrated rubber material.

[0159] By simultaneously vulcanizing the expansion portion 12, the base end portion 11, and the tip portion 113 (normally by press vulcanization), they can be seamlessly integrated. By seamlessly integrating them with rubber material, the base end portion 11 and the tip portion 113 protrude from the expansion portion 12, preventing excessive shear force from being generated at the base of the base end portion 11 and thus preventing damage to the expansion member 110.

[0160] -Modified form 2 of the expansion member- As a second modified form of the expansion member, as shown in Figure 11, a reinforcing cloth 114 may be embedded around the entire inner surface of the expansion portion 12.

[0161] If the weir height is low and the pressure of the gas A filling the inside of the expansion section 12 is small, it can be constructed from a single rubber material as shown in Figure 10. However, if a higher weir height is required, a reinforcing cloth 114 can be embedded around the entire inner circumference of the expansion section 12 as shown in Figure 11, allowing it to withstand higher pressures. The reinforcing cloth 114 may be woven fabric or bamboo blind, but woven fabric is preferred.

[0162] Furthermore, while polyamide fibers, which possess both strength and elasticity, are most preferable as the material for the reinforcing fabric 114, synthetic fibers such as polyester or natural fibers such as cotton can also be used.

[0163] The fabric composition and number of layers of the reinforcing fabric 114 are appropriately selected depending on the weir height and water pressure, but in the case of a single layer, a seamless bag-woven fabric is preferred.

[0164] - Modification 3 of the expansion member - In the third modification of the expansion member, the expansion member 110 has two layers of reinforcing fabric 114. The reinforcing fabric 114 may be provided in three or more layers.

[0165] As shown in Figure 12, in the case of two layers, the required strength can be maintained by shifting the abutment position J1 of the first layer and the abutment position J2 of the second layer.

[0166] - Modification 4 of the expansion member - As shown in Figure 13, the reinforcing cloth 114 may be continuously embedded in the expansion portion 12 from the base end 11 side to the base end 11.

[0167] When a higher weir height is required, the total water pressure on the expansion member 110 becomes very large due to the invading rainwater W, resulting in a large tensile load at the base end 11 of the expansion member 110. To reinforce the base end 11 and prevent damage at the base end 11, it is preferable to bury a continuous reinforcing cloth 114 extending from the expansion section 12 to the base end 11.

[0168] Although not shown in the figures, a reinforcing cloth 114 may be provided in the expansion portion 12 from the tip portion 113 side to the tip portion 113, or a reinforcing cloth 114 may be provided not only on the base portion 11 side of the expansion portion 12 but also on the tip portion 113 side.

[0169] -Modification of the expansion member 5- Also, as shown in Figure 14, by embedding the reinforcing cloth 114 almost entirely up to the tip 113, the rigidity of the tip 113 is increased, preventing the tip 113 from collapsing and overflowing due to tree branches and leaves carried along with rainwater W. In particular, if the reinforcing cloth 114 is embedded entirely from the base end 11 to the expansion part 12 and the tip 113, all of the base end 11, expansion part 12 and tip 113 may be reinforced.

[0170] -Modification 6 of the expansion member- Furthermore, as shown in Figure 15, the expansion member 10 may be provided with a gas inlet 12a leading to an airtight expansion section 12, and a hose 20 may be connected to allow filling with gas A using a compressor 21 or the like. This allows for pressure increase when the pressure of gas A decreases over time.

[0171] (Embodiment 2) Figures 16A and 16B show an expansion member 210 according to Embodiment 2 of the present invention, which differs from Embodiment 1 mainly in the configuration of the expansion portion 212.

[0172] In this embodiment, the expansion member 210 is in the form of a single sheet, and the base ends 11 at both ends of the sheet are overlapped and simultaneously tightened and fixed with the expansion member fixing part 3 to form a hollow expansion part 212.

[0173] Furthermore, a support container 212a is provided inside the expansion section 212 to hold a plurality of foams or hollow resin frames, etc., for holding the gas A.

[0174] This solid support container 212a can maintain the shape of the expansion section 212, and the expansion member 210 can form a flat surface 212b on the upper surface of the side ditch 2 or water tank.

[0175] In this embodiment, in the installation state shown in Figure 16A, a flat surface 212b can be formed on the upper surface of the gutter 2 by the expansion member 210, thereby effectively preventing people and objects from falling into the gutter 2.

[0176] As shown in Figure 16B, when the water level reaches near the maximum level H and the expansion portion 212 stands upright, the upright expansion portion 212 can block the rainwater W, similar to the first embodiment.

[0177] (Embodiment 3) Figures 17A and 17B show Embodiment 3 of the present invention, which differs from Embodiment 2 above mainly in that a stopper portion 314 is provided for the expansion portion 312.

[0178] In this embodiment as well, as in Embodiment 2, a support container 312a is provided inside the expansion portion 312. As shown in Figure 17B, when the expansion member 310 stands upright when it reaches near the maximum water level H, a protrusion 312c is provided at the bottom of the expansion member 310 so that the center of gravity O of the expansion member 310 does not move inward from the side surface S1 on the side of the ditch 2 or water tank site. On the other hand, a stopper 314 is provided on the outer surface S2 of the ditch 2 or water tank site, against which the protrusion 312c abuts. As shown in Figure 17A, a gap is maintained between the protrusion 312c and the stopper 314 so that rainwater W can flow in.

[0179] Thus, when a flat surface 312b is formed on the upper surface of the expansion member 310, the expansion portion 312 does not rest on the ground immediately after the expansion member 310 is erected, unlike the cylindrical expansion member 10. Therefore, adjusting only the free base length Lf may not stabilize the center of gravity O of the expansion member 310 when it is erected.

[0180] Therefore, when using an expansion member 310 with a flat upper surface, in addition to adjusting the free base end length Lf, the protruding portion 312c may be brought into contact with the stopper portion 314 to stabilize the upright position of the expansion member 310.

[0181] As a result, when the water level H approaches the maximum level and the expansion member 310 stands upright, the center of gravity O of the expansion member 310 is located at a distance X1 outside the side surface S1 on the side of the side ditch 2 or water tank. Therefore, when the water level H of the rainwater W drops, the expansion member 310 is automatically and reliably retracted into the side ditch 2 or water tank without any power.

[0182] In this embodiment, since a stopper portion 314 is provided, the expansion member fixing portion 303 may be mounted vertically as shown in Figure 1A, or horizontally as shown in Figure 17A, as long as it is on the upper side of the side S1 on the side of the premises of the side ditch 2 or the water storage tank.

[0183] (Embodiment 4) Figures 18A, 18B, and 19 show Embodiment 4 of the present invention, which differs from Embodiment 1 in that it has a protective member 415.

[0184] In this embodiment, as shown in Figure 18A, the protective member 415 has a pivot point 415a on the ground outside the site S2 of the side ditch 2 or water tank, and is normally installed to cover the side ditch 2 or water tank. It is desirable to recess a protective member housing recess 415b in the periphery of the side ditch 2 so that the upper surface of the protective member 415 and the ground are approximately flush 1, thereby housing the protective member 415.

[0185] As shown in Figure 18B, the protective member 15 stands upright and forms a protective wall as the expanding member 10 is pushed up by the intrusion of rainwater W. On the other hand, as the water level H decreases, the elastic recovery force and self-weight of the expanding member 10, and the self-weight of the protective member 415 cause them to collapse, so that the expanding member 10 and the protective member 415 automatically return to their original state before the intrusion of rainwater W.

[0186] In this way, the protective member 415 prevents large driftwood from directly colliding with the expanding member 10, and under normal circumstances it acts as a cover for the gutter 2 or water tank, preventing people from falling in and allowing people to walk.

[0187] Furthermore, since the pivot point 415a of the protective member 415 is located on the ground S2 outside the site of the side ditch 2 or the water storage tank, it does not rise more than 90°, and therefore does not require stoppers or mooring members like those found in conventional flap gates.

[0188] Furthermore, since the protective member 415 has a structure that allows water to pass through, it is less susceptible to loads directed inward from the site S due to water pressure. Therefore, the structure of the support point 415a does not need to be as high-strength and high-precision as that of conventional flap gates, and a simple hinge is sufficient.

[0189] As shown in Figure 19, the position and length of the pivot point 415a of the protective member 415 are set such that when the expansion member 10 rises to the maximum water level H, the tip position of the protective member 415 exceeds the tangential position of the outer circumference of the expansion section 12.

[0190] As a result, when the water level H drops and the expansion member 10 is automatically retracted into the gutter 2, the tip of the protective member 415 does not get caught on the expansion member 10, and the protective member 415 can also be closed automatically without any power.

[0191] The protective member 415 may be made of a plate-shaped grating made of a lightweight material such as wood or resin. By making the protective member 415 a grating made of a lightweight material such as wood or resin, its weight is light and it floats on water, so it does not resist the expansion member 10 and can be easily raised. In addition, if it is made of wood, it has an excellent appearance as a cover for the side ditch 2 in normal use, and because it is a biomass material CO2 ２ This will also lead to reductions.

[0192] The grating is preferably constructed of wood or resin in a grid pattern, but it may also be made of wood or resin only in the width direction, with thin metal members connecting the wood or resin in the length direction. In any case, it is preferable that the wood or resin in the width direction is stretched across both ends of the side ditch 2, so that people can walk on top of the grating.

[0193] As described above, the installation of the protective member 415 eliminates the risk of damage to the expansion member 10 due to driftwood, etc., resulting in a highly reliable floating bag flap gate 1. Furthermore, under normal circumstances, the protective member 415 acts as a cover for the side ditch 2 or water tank, allowing people to pass through safely.

[0194] (Embodiment 5) Figures 20A, 20B, 20C, and 20D show Embodiment 5 of the present invention, which differs from Embodiment 1 in that it has a metal cover 515 as a protective member.

[0195] In this embodiment, a plate-shaped metal cover 515 is attached to the vehicle passage section R that crosses the side ditch 2 or water tank, with a pivot point on the outside of the side ditch 2 site S2. When the expansion member 10 is erected, biasing means such as a counterweight 530 and a hydraulic cylinder are provided to assist in lifting the area near the tip of the metal cover 515 located on the inside of the side ditch 2 site S1 upward. A slope 516 with a smooth inclined surface may be provided to eliminate the step between the metal cover 515 and the road surface.

[0196] To prevent flooding around the site, an entrance / exit is required for vehicle access. For the passage of extra-large vehicles, lightweight gratings made of wood or similar materials cannot withstand the weight of the vehicles, so a highly rigid metal cover 515 is required for the passage area.

[0197] While the metal cover 515 may be removed in advance if there is a risk of flooding, this would require heavy machinery, personnel, and time. Therefore, a metal cover that can be opened and closed is provided in the vehicle passage area R, and biasing means such as a counterweight 530 or a hydraulic cylinder is provided to assist in the uprighting of the expansion member 10 when it is erected, so that it can be easily opened and closed when the expansion member 10 is erected or collapsed.

[0198] Since the pivot point of the metal cover 515 is located outside the premises S2 of the side ditch 2 or the water storage tank, it does not rise more than 90°, eliminating the need for a stopper, and it closes automatically without power when the water level H drops.

[0199] More specifically, a hinge is provided at the pivot point 515a of the metal cover 515, and a suspension ring is provided at the tip 515b of the metal cover 515. A wire rope 532 is then attached to the suspension ring and pulled upwards. The wire rope 532 is then wrapped around a pulley 531 located above the suspension ring, and a weight is suspended from it to form a counterweight 530.

[0200] The weight of the counterweight 530 and the pressure of the hydraulic cylinder should be set appropriately so that the metal cover 515 does not lift under normal conditions, but when rainwater W enters the gutter 2 and buoyancy is generated in the expansion member 10, causing it to start to stand upright, the metal cover 515 can be easily lifted by the upward pushing force from below by the expansion member 10.

[0201] In the method of pulling up the tip 515b of the metal cover 515, the greatest load is required to open the metal cover 515 in the initial stage when the metal cover 515 is in a horizontal position. As it opens to a certain extent and the metal cover 515 is angled, the required force decreases. However, in the method of pulling up approximately straight up with the wire rope 532, as the angle of the metal cover 515 increases, the wire rope 532 also changes from vertical to diagonal, and the force required to open the metal cover 515 decreases even with the same weight. As a result, the balance between the two is achieved, and the metal cover 515 can be opened gradually with a small force without opening forcefully. When the angle between the wire rope 532 and the metal cover 515 becomes the same, no force acts to open it any further. Therefore, the degree of opening of the metal cover 515 can be arbitrarily adjusted by appropriately setting the height of the pulley 531, making this embodiment an effective biasing method.

[0202] The metal cover 515 should preferably be permeable to rainwater W such as grating. This allows the metal cover 515 to act as a protective element, blocking large pieces of driftwood when it is raised, thus preventing them from colliding with the expansion member 10.

[0203] Of course, only the parts where vehicle traffic is required may be fitted with metal gratings (metal covers 515 and protective members) with counterweights 530, while the remaining parts may be fitted with protective members 415 made of lightweight gratings such as wood.

[0204] As described above, by using the expansion member 10 and the protective member 415 (metal cover 515) in combination, a simple, inexpensive, safe, and reliable floating bag flap gate 1 that covers the entire site can be realized. Furthermore, by providing a metal cover in the vehicle passage area R, a highly versatile flap gate that can also accommodate heavy machinery can be realized.

[0205] The embodiments described above are essentially preferred examples and are not intended to limit the scope of the present invention, its applications, or uses.

[0206] 1 Floating bag flap gate 2 Side channel 3, 3' Inflation member fixing part 3a Anchor bolt 3b Nut 3c Metal plate on one side 3d Separate metal plate 10, 110, 210, 310, 610, 610' Inflation member 11, 611 Base end 11a Free base end 12, 212, 312, 612 Inflation part 12a Gas inlet 20 Hose 21 Compressor 113, 613 Tip 114 Reinforcement cloth 212a Support container 212b Flat surface 303 Inflation member fixing part 312a Support container 312b Flat surface 312c Protruding part 314 Stopper part 415 Protective member 415a Pivot point 415b Protective member housing recess 515 Metal cover (protective member) 515a Pivot point 515b Tip 530 Counterweight 531 Pulley 532 Wire rope 616 Vulcanized joint 617, 617'' Joint plate 618 Bolt 619'' Flexible rubber sheet 620 Corner 621'' Waterproof sheet A Gas B Building O Center of gravity R Vehicle traffic area S1 Inside the site S2 Outside the site W Rainwater

Claims

1. A floating bag flap gate for preventing flooding of a site due to sudden heavy rain, comprising: a gutter or water tank installed around the site to be flooded; an expansion member fixing part continuously installed on the site side of the gutter or water tank; and a long bag-shaped expansion member having an expansion part filled with gas and a base end that is continuously and watertightly fixed to the expansion member fixing part, wherein when rainwater enters the gutter or water tank and the water level rises, buoyancy is generated in the expansion member, and the expansion member rotates and stands upright, causing it to float and form a waterproof wall, the bag structure of the expansion member and the mooring at the expansion member fixing part maintain a high weir height, and when the water level of the incoming rainwater fills the gutter or water tank, the center of gravity of the gas-filled expansion member is located outside the side surface position on the site side of the gutter or water tank. Furthermore, the floating bag flap gate is configured such that when the water level of incoming rainwater rises above the level of the gutter or water tank, a tensile load is generated at the free base end of the base end of the expansion member that is not fixed by the expansion member fixing part, and an elastic restoring force is generated at the free base end due to the tensile load, which pulls the expansion member back outwards from the site, and when the water level of rainwater drops to a level that fills the gutter or water tank, the center of gravity of the expansion member is located outside the side surface position on the site side of the gutter or water tank, so that the expansion member is automatically retracted into the gutter or water tank without power.

2. The floating bag flap gate according to claim 1, characterized in that the side ditch or water tank has a corner that curves in a direction that surrounds at least one location of the site, the expansion member is configured to rotate and stand up at the corner simultaneously with the straight section to continuously form a waterproof wall and to be automatically stored in the side ditch or water tank, the expansion member is joined at the corner with a vulcanized joint or a clamping joint with an elongated plate material such that the length of one side in the longitudinal direction increases from the base end toward the tip, and the base end is continuously fixed to the expansion member fixing part, straddling the corner.

3. The floating bag flap gate according to claim 2, characterized in that when the bending angle at the corner on the side of the side ditch or water tank on the site side is α, the joint angle β at the base end side of the clamping joint at the corner of the expansion member is set within the range of (360-α) / 2-22.5 ≤ β ≤ (360-α) / 2+22.

5.

4. The floating bag flap gate according to claim 1, characterized in that it has a corner of the side ditch or water tank that curves in a direction that surrounds at least one location of the site, and at the corner it rotates and stands upright simultaneously with the straight section to continuously form a waterproof wall, and is configured to automatically be stored inside the side ditch or water tank, and the end faces of the expansion member that abut in the longitudinal direction and a flexible rubber sheet for corner protection are sandwiched and joined by a plate material.

5. The floating bag flap gate according to claim 1, characterized in that the length Lf of the flexible free base portion is 20% to 150% of the shortest wrapping distance Lmin from the end of the expansion member fixing portion to the ground on the side of the ditch or water tank site.

6. The floating bag flap gate according to claim 5, characterized in that the free base end length Lf is 70% or more and 100% or less of the shortest winding distance Lmin.

7. The floating bag flap gate according to claim 5, characterized in that an inclined section is provided on the side of the ditch within the premises, the free base length Lf is set so that when the water level rises to its maximum and the expansion member is in a fully upright state, the bottom of the expansion member rests on the inclined section, and when the water level drops, the expansion member rolls down the inclined section by its own weight, so that when the rainwater level drops to a level that fills the ditch or water tank, the center of gravity of the expansion member is located outside the side surface position on the premises of the ditch or water tank, and the expansion member is automatically stored in the ditch or water tank without power.

8. The floating bag flap gate according to claim 1 or 2, characterized in that the expansion portion has a hollow structure, the integrally formed base end has a solid structure, and the base end protrudes from the expansion portion when the expansion portion is filled with gas.

9. The floating bag flap gate according to claim 1 or 2, characterized in that the expansion portion has a hollow structure, the integrally formed base end has a solid structure, and it further has an integrally formed solid tip, the tip protrudes from the expansion portion when the expansion portion is filled with gas, and the tip is at a higher position than the expansion portion when the maximum water level is reached.

10. The floating bag flap gate according to claim 1 or 2, characterized in that the expansion portion and the base end of the expansion member are made of a seamlessly integrated rubber material.

11. The floating bag flap gate according to claim 10, characterized in that the expansion portion has a reinforcing cloth embedded around its entire inner surface.

12. The floating bag flap gate according to claim 10, characterized in that a reinforcing cloth is continuously embedded from the expansion portion to the base end.

13. The floating bag flap gate according to claim 10, characterized in that the expansion member has a gas inlet that leads to the expansion section, and a hose is connected to the gas inlet so that gas can be filled in.

14. The floating bag flap gate according to claim 1, characterized in that the expansion member is in the form of a single sheet, the base ends at both ends of the sheet are overlapped and simultaneously tightened and fixed with the expansion member fixing part to form a hollow expansion section, and the shape of the expansion section is maintained by placing a support container that holds gas, such as a plurality of foams or a hollow frame, into the expansion section, and further configured such that a flat surface is formed on the upper surface of the side ditch or water tank by the expansion member.

15. The floating bag flap gate according to claim 14, characterized in that when the expansion member is erected to a large extent when it reaches near the maximum water level, a protrusion is provided at the lower part of the expansion member so that the center of gravity of the expansion member does not move inward from the side surface position within the site of the side ditch or water tank, and a stopper is provided so that the protrusion can abut against the outer surface of the site of the side ditch or water tank.

16. The floating bag flap gate according to claim 1 or 2, characterized in that the expansion member fixing portion is provided on the upper side of the side surface within the site of a side ditch or water storage tank.

17. A floating bag flap gate according to claim 1 or 2, characterized in that it has a pivot point on the ground outside the site of a side ditch or water tank, is normally installed to cover the side ditch or water tank, and is provided to stand up when the expansion member is erected, allowing rainwater to pass through but blocking driftwood and preventing driftwood from colliding with the expansion member, and is configured such that the expansion member and the protective member automatically return to their original state before rainwater intrusion without power as the expansion member rises up due to the intrusion of rainwater, and as the water level drops and the expansion member descends, the protective member collapses under its own weight.

18. The floating bag flap gate according to claim 17, characterized in that the pivot point position and length of the protective member are set such that when the rainwater reaches the maximum water level and the expansion member is fully upright, the tip position of the protective member exceeds the tangent to the outer circumference of the expansion member.

19. The floating bag flap gate according to claim 17, characterized in that the protective member is a grating made of a lightweight material such as wood or resin.

20. The floating bag flap gate according to claim 1, characterized in that a metal cover having a pivot point on the outside of the drainage ditch is attached to the vehicle passage section crossing the drainage ditch or water tank, and a biasing means such as a counterweight or hydraulic cylinder is provided to assist in lifting upward the area near the tip of the metal cover on the inside of the drainage ditch when the expansion member is erected.

21. The floating bag flap gate according to claim 20, characterized in that the metal cover is permeable to rainwater such as a grating, and is configured to block large driftwood as a protective member when it is raised, thereby preventing large driftwood from colliding with the expansion member.

22. A waterproofing method using a floating bag flap gate to prevent flooding of a site due to sudden heavy rain, comprising: a gutter or water tank installed around the site to be flooded; an expansion member fixing part continuously installed on the site side of the gutter or water tank; and a floating bag flap gate composed of an expansion member having an expansion part filled with gas and a base end that is continuously and watertightly fixed to the expansion member fixing part; when rainwater enters the gutter or water tank and the water level rises, buoyancy is generated in the expansion member, and the expansion member rotates and stands upright, causing it to float and form a waterproof wall; and when the water level of the invading rainwater fills the gutter or water tank, the center of gravity of the gas-filled expansion member is located outside the side surface position on the site side of the gutter or water tank. Furthermore, a waterproofing method using a floating bag flap gate, characterized in that when the water level of incoming rainwater rises above the level of the gutter or water tank, a tensile load is generated at the free base end of the base end of the expansion member that is not fixed by the expansion member fixing part, and an elastic restoring force is generated at the free base end due to the tensile load, which pulls the expansion member back toward the outside of the site, and when the water level of rainwater drops to a level that fills the gutter or water tank, the center of gravity of the expansion member is located outside the side surface position on the site of the gutter or water tank, thereby automatically retracting the expansion member into the gutter or water tank without power.

23. A waterproofing method using a floating bag flap gate according to 22, characterized in that the floating bag flap gate is further provided with a protective member which has a pivot point on the ground outside the site of the side ditch or water tank, is normally installed to cover the side ditch or water tank, stands up when the expansion member is erected, allows rainwater to pass through but blocks driftwood, and prevents driftwood from colliding with the expansion member, and when the expansion member floats up due to the intrusion of rainwater, the protective member stands up and forms a protective wall, and when the expansion member descends due to the decrease in water level, the protective member collapses under its own weight, so that the expansion member and the protective member automatically return to their original state before the intrusion of rainwater without any power.

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