1. A floating flap gate installed on a road surface at an entrance portion of a building or an underground space in order to block the entrance portion at a time of rising water, and configured so that a distal end side of a gate leaf is able to swing upward in a height direction along a water inflow direction around a proximal end side of the gate leaf as a fulcrum, the floating flap gate comprising: an upward swinging support portion provided on the proximal end side of the gate leaf; wherein the upward swinging support portion comprises; a bottom fitting mounted to an end portion of the gate leaf on the proximal end side, having a convex circular arc-shaped surface formed at a proximal end side corner portion of a surface of the gate leaf in a lowered state, and having a length equal to a width of the gate leaf; a resin plate having a concave circular arc-shaped surface to be mated with the convex circular arc-shaped surface of the bottom fitting, configured to support the gate leaf in a raised state as a receiving seat to receive a portion of the bottom fitting in which portion the convex circular arc-shaped surface is formed, and being equal in length with the bottom fitting; a waterproof membrane disposed on a surface side of each of the bottom fitting and the resin plate so as to cover the bottom fitting and the resin plate; a first seal clamp mounted on the surface side of the bottom fitting so as to integrally sandwich a portion of the waterproof membrane which portion covers the bottom fitting, between itself and the bottom fitting; and a second seal clamp mounted on the surface side of the resin plate so as to integrally sandwich another portion of the waterproof membrane which portion covers the resin plate, between itself and the resin plate or a base disposed on the proximal end side of the gate leaf.

2. The floating flap gate as claimed in claim 1, wherein when the gate leaf in a raised state has floated up due to buoyancy and water pressure, the gate leaf is supported via the waterproof membrane at an end portion of the second seal clamp on a side of the first seal clamp.

3. The floating flap gate as claimed in claim 1 or 2, wherein when the gate leaf is lowered, a gap is present between the convex circular arc-shaped surface of the bottom fitting and the concave circular arc-shaped surface of the resin plate.

TECHNICAL FIELD
[0001] The present invention relates to a floating flap gate that is
installed on a road surface at an entrance portion of a building or an underground space in order to prevent, for example, at the time of rising water, the rising water from flowing into the building or the underground space by raising, at the time of rising water, a gate leaf to block the entrance portion.
BACKGROUND
[0002] In some cases, on a road surface at an entrance portion of a
building or an underground space, a floating flap gate that is configured to block said entrance portion is installed in order to prevent, at the time of rising water, the rising water from flowing into the building or the underground space.
[0003] The floating flap gate of this type has a configuration in which
the gate leaf is provided with a buoyancy forming portion, and by using water pressure of water flowing into the entrance portion of the building or the underground space and buoyancy of the gate leaf itself, the gate leaf is raised to block said entrance portion.
[0004] The gate leaf of the floating flap gate is installed on the road
surface or a receiving base provided on the road surface so as to be freely rotatable via a hinge provided at each of two locations on the gate leaf in a width direction thereof (see, for example, Patent Literature 1).
[0005] In a case, however, where the gate leaf is structured to be raised
via the hinge, such a complicated structure requires higher levels of manufacturing precision and assembly precision, resulting in an increase in manufacturing man-hour. Furthermore, a load acting on the gate leaf is concentrated on the hinge, thus requiring a frame that is a component of the

gate leaf to have high strength.
RELEVANT REFERENCES LIST OF RELEVANT PATENT LITERATURES [0006]
Patent Literature 1: JP H10-121444 A
SUMMARY
[0007] The present invention is to solve a problem that the floating flap
gate having a configuration in which the gate leaf is installed on a road surface or the receiving base provided on the road surface so as to be freely rotatable via the hinge is complicated in structure, resulting in an increase in manufacturing man-hour. Furthermore, the present invention is also to solve another problem that a load is concentrated on the hinge, thus requiring the frame that is a component of the gate leaf to have high strength.
[0008] The present invention has been made to achieve an object to
structurally simplify a frame that is a component of a gate leaf and reduce required levels of manufacturing precision and assembly precision, thereby reducing a manufacturing man-hour, based on a simplification of a support portion structure of the gate leaf by adopting a structure in which a load acting on the gate leaf is not concentrated thereon but dispersed.
[0009] The present invention is to provide a floating flap gate that is
installed on a road surface at an entrance portion of a building or an underground space in order to block the entrance portion at the time of rising water, and configured so that a distal end side of the gate leaf is able to swing upward in a height direction along a water inflow direction around a proximal end side of the gate leaf as a fulcrum. The floating flap gate is characterized

most principally in that an upward swinging support portion that is provided
on the proximal end side of the gate leaf is composed of a bottom fitting, a
resin plate, a waterproof membrane, a first seal clamp, and a second seal
clamp, which are described below.
[0010] The bottom fitting is mounted to an end portion of the gate leaf
on the proximal end side, has a length equal to a width of the gate leaf, and has
a convex circular arc-shaped surface formed at a proximal end side corner
portion of a surface of the gate leaf in a lowered state.
[0011] The resin plate is to support the gate leaf in a raised state as a
receiving seat to receive a portion of the bottom fitting in which portion the
convex circular arc-shaped surface is formed, is equal in length to the bottom
fitting, and has a concave circular arc-shaped surface to be mated with the
convex circular arc-shaped surface of the bottom fitting.
[0012] The waterproof membrane is disposed on a surface side of each
of the bottom fitting and the resin plate so as to cover the bottom fitting and
the resin plate.
[0013] The first seal clamp is mounted on the surface side of the bottom
fitting so as to integrally sandwich a portion of the waterproof membrane
which portion covers the bottom fitting, between itself and the bottom fitting.
[0014] The second seal clamp is mounted on the surface side of the
resin plate so as to integrally sandwich a portion of the waterproof membrane
which portion covers the resin plate, between itself and the resin plate or a
base disposed on the proximal end side of the gate leaf.
[0015] In the present invention described above, the gate leaf is
supported in such a manner that the portion of the bottom fitting mounted to
the end portion of the gate leaf on the proximal end side and having a length
equal to a width of the gate leaf, in which the convex circular arc-shaped

surface is formed, is received by the resin plate as the receiving seat, which has the concave circular arc-shaped surface to be mated with the convex circular arc-shaped surface and is equal in length to the bottom fitting. Accordingly, the gate leaf can be supported, with a load acting by itself being dispersed, and thus a frame that is a component of the gate leaf can be structurally simplified.
[0016] Furthermore, the support portion of the gate leaf is composed of
the bottom fitting, the resin plate, the waterproof membrane disposed so as to cover the bottom fitting and the resin plate, the first seal clamp that integrally sandwiches the waterproof membrane between itself and the bottom fitting, and the second seal clamp that integrally sandwiches the waterproof membrane between itself and the resin plate or the base. Accordingly, a configuration of the support portion can be simplified, and thus it is possible to reduce required levels of manufacturing precision and assembly precision and hence a manufacturing man-hour.
ADVANTAGES
[0017] According to the present invention, the gate leaf can be
supported, with a load acting by itself being dispersed, and thus a frame that is a component of the gate leaf can be structurally simplified. Furthermore, a configuration of the support portion can be simplified, and thus it is possible to reduce required levels of manufacturing precision and assembly precision and hence a manufacturing man-hour.
BRIEF DESCRIPTION OF THE DRAWINGS [0018]Fig. 1 is a view, as seen from a side, of a floating flap gate of the present invention as a whole.
Fig. 2 is an enlarged view of a proximal end side of a gate leaf shown in

Fig. 1.
Fig. 3 is an enlarged view of an upward swinging support portion of the gate leaf shown in Fig. 1.
Fig. 4 is a view, as seen from a side of the upward swinging support portion, showing a state where, in the floating flap gate of the present invention when raised, a weight of the gate leaf is supported by a resin plate.
Fig. 5 is a view, as seen from the side of the upward swinging support portion, showing a state of supporting a hydraulic load in a case where, in the floating flap gate of the present invention when raised, the gate leaf has floated up under said hydraulic load.
Fig. 6 is a view explaining another configuration of a waterproof membrane.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0019] The present invention has as its object to structurally simplify a
frame of a gate leaf by adopting a structure in which a load acting on the gate leaf is dispersed and to reduce required levels of manufacturing precision and assembly precision, thereby reducing a manufacturing man-hour.
[0020] Further, the present invention has achieved the object by
adopting a structure in which the end portion of the gate leaf on the proximal end side is supported in such a manner that the portion of the bottom fitting having a length equal to a width of the gate leaf, in which the convex circular arc-shaped surface is formed, is received by the resin plate as the receiving seat, which has the concave circular arc-shaped surface to be mated with the convex circular arc-shaped surface and is equal in length to the bottom fitting.
EMBODIMENTS
[0021] With reference to Fig. 1 to Fig. 5, the following describes one

embodiment of the present invention in detail. Fig. 1 is a view, as seen from a side, of a floating flap gate of the present invention as a whole, Fig. 2 is an enlarged view of a proximal end side of a gate leaf shown in Fig. 1, and Fig. 3 is an enlarged view of an upward swinging support portion of the gate leaf shown in Fig. 1.
[0022] In Fig. 1 to Fig. 3, reference number 1 denotes a floating flap gate
of the present invention. The floating flap gate 1 may be installed, usually in a lowered state, on a road surface “rs” between side walls 2 installed at, for example, an entrance portion of a building or an underground space. The floating flap gate 1 blocks the entrance portion in a water-tight state by raising the end portion 4b of the gate leaf 4 having buoyancy generating ability on the distal end side thereof with an end portion 4a of the gate leaf 4 on a proximal end side thereof as a fulcrum by using pressure of water flowing into an entrance portion of a building or an underground space. Hereinafter, the end portion of the gate leaf 4 on the proximal end side is referred to as a proximal end portion 4a. Furthermore, the end portion thereof on the distal end side is referred to as a distal end portion 4b.
[0023] In the floating flap gate 1 of the present invention, an upward
swinging support portion provided at the proximal end portion 4a of the gate leaf 4 may have a configuration described below.
[0024] Reference number 5 denotes a bottom fitting of, for example, an
L shape that may be mounted in a water-tight state so as to be in contact with an end surface 4aa of the gate leaf 4 in the proximal end portion 4a and a surface 4d of the gate leaf 4 in the lowered state. The bottom fitting 5 may have a length equal to a width of the gate leaf 4 so as to exist over an entire region of the gate leaf 4 in a width direction thereof. Further, a portion of the bottom fitting 5, which is in contact with the surface 4d of the gate leaf 4, may

be made to protrude in an opposite direction to the distal end portion 4b of the
gate leaf 4, forming a convex circular arc-shaped surface 5a on a side opposed
to the road surface “rs”. Hereinafter, the portion made to protrude to form the
convex circular arc-shaped surface 5a is referred to as a protruding portion 5b.
[0025] Reference number 6 denotes a resin plate that may have a length
equal to the length of the bottom fitting 5 and have a surface opposed to the
convex circular arc-shaped surface 5a of the bottom fitting 5, which is formed
in such a concave circular arc shape as to be mated with the convex circular
arc-shaped surface 5a. Hereinafter, this surface formed in the concave
circular arc shape is referred to as a concave circular arc-shaped surface 6a.
[0026] In an embodiment shown in Fig. 1 to Fig. 3, the gate leaf 4 in the
lowered state may be supported on a back surface 4c thereof on its distal end
side and its proximal end side by a plurality of gate leaf receiving members 11
disposed at a predetermined interval therebetween in the height direction (a
direction parallel to a plane of each of Fig. 1 to Fig. 3) of the gate leaf 4. Each
of the gate leaf receiving members 11 may have a receiving surface 11a to
receive the gate leaf 4b and a screw shaft 11b provided on an opposite side to
the receiving surface 11a. Each of the gate leaf receiving members 11 may be
configured to be able to adjust a position of the receiving surface 11a in a
height direction, which supports the gate leaf 4 in the lowered state, by screw-
fitting the screw shaft 11b into a female screw member 10 securely disposed
on a lower surface of a horizontal member 9 connecting a middle portion of a
base 8 in a height direction, which is provided on the proximal end side of the
gate leaf 4, to a middle portion of a gate leaf distal end receiving member 7 in a
height direction, which is provided on the distal end side of the gate leaf 4.
[0027] The gate leaf distal end receiving member 7 that is in contact
with the distal end side of the gate leaf 4 in the lowered state and the base 8

provided on the proximal end side of the gate leaf 4 may have a length equal to
the width of the gate leaf 4.
[0028] The resin plate 6 may be placed on a resin plate receiving
member 12 disposed on the horizontal member 9. When the gate leaf 4 is in
the lowered state and thus is supported by the door receiving members 11, a
gap “s“ may be formed between the concave circular arc-shaped surface 6a of
the resin plate 6 and the convex circular arc-shaped surface 5a of the bottom
fitting 6 (see Fig. 3).
[0029] Reference number 13 denotes a waterproof membrane that is
disposed to extend over a surface 5c of the bottom fitting 5 and a surface 6b of
the resin plate 6. The waterproof membrane 13 cover the bottom fitting 5 and
the resin plate 6, thus preventing water leakage from, for example, the gap “s”
between the bottom fitting 5 and the resin plate 6, a space between the resin
plate 6 and the base 8, or the like.
[0030] On a portion of the waterproof membrane 13, which covers the
bottom fitting 5, a first seal clamp 14 is disposed. The first seal clamp 14, the
waterproof membrane 13, and the bottom fitting 5 are integrally fastened
together by, for example, a bolt 15.
[0031] Furthermore, on another portion of the waterproof membrane
13, which covers the resin plate 6, a second seal clamp 16 is disposed. The
second seal clamp 16, the waterproof membrane 13, and, for example, the
base 8 may be integrally fastened together by another bolt 15.
[0032] In order to be able to support the bottom fitting 5 via the
waterproof membrane 13 when the gate leaf 4 has been raised and floated up
under buoyancy and water pressure, the second seal clamp 16 may have such
a length that an end portion 16a thereof on a first seal clamp 14 side extends
to above the protruding portion 5b of the bottom fitting 5.

[0033] In the floating flap gate 1 of the present invention configured as
above, in a case where water flows in to cause the gate leaf 4 to be raised, as shown in Fig. 4, the concave circular arc-shaped surface 6a of the resin plate 6 may function as a receiving seat to receive the protruding portion 5b of the bottom fitting 5 and support a weight of the gate leaf 4 at a position indicated by an arrow. That is, in the present invention, the bottom fitting 5 and the waterproof membrane 13 may fulfill a hinge function.
[0034] On the other hand, in a case where the gate leaf 4 in a raised
state floats up under buoyancy and water pressure, as shown in Fig. 5, the gate leaf 4 under buoyancy and water pressure may be supported at the end portion 16a (a position indicated by an arrow) of the second seal clamp 16 on the first seal clamp side.
[0035] When the gate leaf 4 under buoyancy and water pressure is
supported in such a state, the waterproof membrane 13 may be subjected to a tensile load. Accordingly, in order to suppress stretching of the waterproof membrane 13 when subjected to a tensile load, it may be desirable that a fiber-containing film is used as the waterproof membrane 13.
[0036] Furthermore, together with a tensile load, a pull-out load may be
exerted on the waterproof membrane 13, and thus it may be desirable that the
waterproof membrane 13 is shaped to be thicker at end portions 13a thereof
on each of the distal end side and the proximal end side of the gate leaf 4 than
at a center portion thereof so that the waterproof membrane 13 is prevented
from being pulled out even when a pull-out load is exerted thereon.
[0037] Needless to say, the present invention is not limited to the
above-described example, and changes can be made to the embodiment as
appropriate without departing from the technical scope recited in the claims.
[0038] For example, as shown in Fig. 6, it may also be possible that the

waterproof membrane 13 has a double structure composed of a fiber film 13b
having tensile strength and a rubber film 13c having a water cut-off capability..
[0039] Furthermore, while the above-described example has explained a
case where the floating flap gate 1 of the present invention is installed at an entrance portion of a building or an underground space, the floating flap gate 1 of the present invention can be installed also at, without being limited to an entrance portion of a building or an underground space, for example, an opening portion of a seawall or a breakwater.
LIST OF REFERENCE NUMBERS [0040]
1 floating flap gate
4 gate leaf
4a proximal end portion
4b distal end portion
4d surface
5 bottom fitting
5a convex circular arc-shaped surface
5b protruding portion
5c surface
6 resin plate
6a concave circular arc-shaped surface
6b surface
8 base
13 waterproof membrane
14 first seal clamp
16 second seal clamp

I/We Claim:
1. A floating flap gate installed on a road surface at an entrance portion of
a building or an underground space in order to block the entrance portion at a time of rising water, and configured so that a distal end side of a gate leaf is able to swing upward in a height direction along a water inflow direction around a proximal end side of the gate leaf as a fulcrum, the floating flap gate comprising:
an upward swinging support portion provided on the proximal end side of the gate leaf;
wherein the upward swinging support portion comprises;
a bottom fitting mounted to an end portion of the gate leaf on the proximal end side, having a convex circular arc-shaped surface formed at a proximal end side corner portion of a surface of the gate leaf in a lowered state, and having a length equal to a width of the gate leaf;
a resin plate having a concave circular arc-shaped surface to be mated with the convex circular arc-shaped surface of the bottom fitting, configured to support the gate leaf in a raised state as a receiving seat to receive a portion of the bottom fitting in which portion the convex circular arc-shaped surface is formed, and being equal in length with the bottom fitting;
a waterproof membrane disposed on a surface side of each of the bottom fitting and the resin plate so as to cover the bottom fitting and the resin plate;
a first seal clamp mounted on the surface side of the bottom fitting so as to integrally sandwich a portion of the waterproof membrane which portion covers the bottom fitting, between itself and the bottom fitting; and
a second seal clamp mounted on the surface side of the resin plate so as

to integrally sandwich another portion of the waterproof membrane which portion covers the resin plate, between itself and the resin plate or a base disposed on the proximal end side of the gate leaf.
2. The floating flap gate as claimed in claim 1, wherein when the gate leaf in a raised state has floated up due to buoyancy and water pressure, the gate leaf is supported via the waterproof membrane at an end portion of the second seal clamp on a side of the first seal clamp.
3. The floating flap gate as claimed in claim 1 or 2, wherein when the gate leaf is lowered, a gap is present between the convex circular arc-shaped surface of the bottom fitting and the concave circular arc-shaped surface of the resin plate.