JP7726095B2 - Fall prevention fence - Google Patents

Description

The present invention relates to fall prevention fences that are installed on river or sea embankments to prevent people and vehicles from falling, and in particular to fall prevention fences that are not likely to be damaged even when heavy rain occurs and river water overflows the embankment.

Water used at power plants is released into rivers, the sea, etc. using a discharge channel. As shown in Figure 9(a), if vehicles and people are allowed to approach the outlet (discharge port 54) of the discharge channel 56, a fall prevention fence 50, as shown in Figure 9(b), is installed on a levee 53 near the border with the river 55 to prevent falls. Figure 9(a) shows an example of a location where a conventional fall prevention fence 50 is installed. The dashed line in the figure indicates the area where the discharge channel 56 is formed underground, and the small circles lined up in a row along the river 55 represent the posts 51 that make up the fall prevention fence 50. Figure 9(b) shows the fall prevention fence 50 in Figure 9(a) as seen from the river 55 side.

If the water level of the river 55 rises due to heavy rain or other events, causing overflow (water in the river 55 overflowing the levee 53), the fall prevention fence 50 may be damaged or deformed by collisions with the flowing sediment or the force of the water current. Therefore, when it is predicted that the water level of the river 55 will rise due to heavy rain or other events, the fall prevention fence 50 is manually removed before the water level of the river 55 rises and overflows, and then reinstalled after the water level of the river 55 returns to its original state. However, because the fall prevention fence 50 is constructed of many posts 51 connected to each other via wires 52, it is not easy to remove and reinstall it every time heavy rain or other events occur. As such, conventional fall prevention fences 50 have the problem of requiring an extremely long time and cost for removal and restoration work.

Although it is not something that is installed on river embankments or the like, for example, Patent Document 1 discloses an invention entitled "Device for preventing drifting objects from flowing out," which does not normally impede the passage of vehicles or the like, but when a tsunami strikes, prevents drifting objects such as containers from flowing inland or out to sea from port facilities located on the sea side.
The invention disclosed in Patent Document 1 has a structure with a net-like lifting fence consisting of a fence rope and a fence chain, which is installed between a pair of support members and rises and falls by the weight of a weight member.
With this structure, when not in use, the lift-up fence can be lowered without power to prevent it from obstructing vehicle traffic, and when a tsunami strikes, the lift-up fence can be raised without power to prevent containers and other items from being swept away.

Furthermore, Patent Document 2 discloses an invention entitled "Fence for preventing falls on embankments," which relates to a fence that is installed on an embankment to prevent children and others from falling into a waterway formed at an intake for irrigation water, etc., installed in a river.
The invention disclosed in Patent Document 2 has a structure that includes a fence body consisting of multiple posts erected on the ground and ropes stretched between the posts, hinges attached to the legs of the fence body that allow the fence body to rotate freely in the direction of the river flow, and fixing means that prevents the hinges from rotating, maintaining the fence body in an upright position, and that can be released from the upright position by operating an operating unit.
With this structure, even if the water level of the river rises suddenly due to heavy rain or other reasons, the operating part can be operated to release the upright state of the fence body, allowing the fence body to fall downstream in accordance with the flow of the river, thereby preventing damage to the fence body.

Furthermore, Patent Document 3 discloses an invention entitled "Port Entrance Blocking Structure" relating to a port entrance structure for preventing illegal entry of ships that are not permitted to enter the port.
The invention disclosed in Patent Document 3 has a structure comprising a lower steel pipe buried in the seabed, a plurality of lifting devices consisting of flotation steel pipes inserted into the lower steel pipes and raised and lowered by the buoyancy of air supplied inside, blocking members consisting of horizontal and vertical mooring ropes stretched between adjacent flotation steel pipes, and a drive unit for raising and lowering the lifting devices.
With this structure, by raising the floating steel pipe and placing the upper parts of the horizontal and vertical mooring lines above sea level, it is possible to prevent suspicious ships that are not permitted to enter the port, such as fishing boats and small cargo ships sailing on the sea, from entering the port.

JP 2015-206231 A Japanese Patent Application Publication No. 1-260181 JP 2012-97419 A

The invention disclosed in Patent Document 1 has a structure in which the lifting fence rises when the sea level rises, such as when a tsunami hits, and there is no concept of preventing the lifting fence from being damaged by the force of the water. Therefore, it cannot be used for the purpose of preventing fall prevention fences from being damaged by the force of the water when the water level of rivers or the sea rises.
Furthermore, the invention disclosed in Patent Document 2 is designed so that the fence body falls downstream along with the river flow if the water level of the river rises suddenly, which prevents damage to the fence body itself, but it has the problem that it cannot prevent damage to the mechanisms that rotate the fence body, such as hinges.
Furthermore, since the invention disclosed in Patent Document 3 involves operating a drive device to raise and lower a lifting device, if this invention is used in a fall prevention fence and the posts of the fall prevention fence are designed to be stored underground when the water level of a river rises, there is a risk that damage to the posts cannot be prevented unless the drive device is operated at the appropriate time.

The present invention was made in response to these conventional circumstances, and aims to provide a fall prevention fence that can be installed on river or sea embankments and that will not be damaged even if it does not need to be removed in the event of heavy rain or other events that cause overflowing water.

In order to achieve the above object, the first invention is a fall prevention fence to be installed on a river or sea embankment, comprising: a horizontal hole formed inside the embankment; a support post insertion hole formed parallel to the vertical direction from the top surface of the embankment so that its lower end opens to the top of the horizontal hole; a support post loosely inserted into the support post insertion hole; a rod-shaped support whose upper end is swingably connected to the lower end of the support post and which is installed inside the horizontal hole in an inclined state with respect to the vertical direction to support the support post; a float installed on an inclined surface provided at the bottom of the horizontal hole and connected to the lower end of the support post; and guide means fixed to the inner wall of the embankment and which holds the support post in a swingable manner, wherein a water intake hole is provided at the bottom of the horizontal hole to allow river or sea water to flow inside, the float has a specific gravity less than 1 and is installed so that it can move downward along the inclined surface under its own weight, and the support post is installed so that it swings in a direction that the angle it makes with the vertical direction decreases as the float descends.
In the first invention, when river or seawater flows into the horizontal cavern through the water intake hole and the water level in the horizontal cavern rises, the float rises, causing the support device to swing in a direction that increases the angle it forms with the vertical, resulting in the upper end of the support device moving downward. The support pole then descends, as if pulled by the support pole. Furthermore, when the water level in the horizontal cavern drops as water is discharged out through the water intake hole, the float also descends, causing the support device to swing in a direction that decreases the angle it forms with the vertical. As a result, the upper end of the support pole moves upward, and the support pole rises, pushing up the lower end. In other words, in the first invention, when the water level in the horizontal cavern rises due to rising river or seawater, the support pole descends, with the lower part retracted into the levee, and as the water level in the horizontal cavern drops, the support pole rises, causing the part that was retracted into the levee to emerge above ground.

A second invention is characterized in that, in the first invention, the float is provided with wheels that are installed so as to be able to roll along the inclined surface.
In addition to the effect of the first invention, the second invention has the effect that the float is more likely to move downward along the inclined surface due to its own weight than the first invention.

The third invention is characterized in that, in the second invention, the float has a hollow container provided with a bearing portion that holds the lower end of the support device in a swingable manner, and a wheel is rotatably attached to this hollow container.
In the third invention, in addition to the effect of the second invention, the specific gravity of the entire float can be changed by changing the amount of liquid stored inside the hollow vessel.

The fourth invention is characterized in that, in any of the first to third inventions, it is provided with a connecting device that is installed at the lower end of the support and rotatably holds the upper end of the support.
In the fourth invention, in addition to the effect of any one of the first to third inventions, when there are supports of various sizes, it is not necessary to perform processing to provide a mechanism for swingably holding the upper end of each support at the lower end of each support.

The fifth invention is characterized in that, in any of the first to fourth inventions, the support has a convex portion on the side between the upper and lower ends that serves as a rotation axis, and the guide means comprises a guide member that engages with the upper surface of the convex portion to allow horizontal movement while restricting upward movement.
In the fifth invention, in addition to the action of any of the first to fourth inventions, when the water level in the horizontal hole rises and the float surfaces, the support device has the action of swinging in a direction that increases the angle it forms with the vertical direction while the convex portion moves horizontally along the guide member of the guide means.

The sixth invention is characterized in that, in any of the first to fourth inventions, the invention is provided with a rotating tool having a convex portion serving as a rotation axis provided on the side of a cylindrical body into which the support tool is loosely inserted, protruding in a direction perpendicular to the longitudinal direction of the cylindrical body, and the guide means comprises a rotating tool holding member that rotatably holds the convex portion of the rotating tool.
In the sixth invention, in addition to the action of any of the first to fourth inventions, when the water level in the horizontal hole rises and the float rises, the support device moves longitudinally inside the cylindrical body of the rotating device and oscillates in a direction that increases the angle it forms with the vertical direction, and when the water level in the horizontal hole drops and the float drops, the support device moves longitudinally inside the cylindrical body of the rotating device and oscillates in a direction that decreases the angle it forms with the vertical direction.

The seventh invention is characterized in that, in any one of the first to sixth inventions, a mesh body is installed at the open end of the water intake facing the river or the sea.
In the seventh invention, in addition to the effect of any one of the first to sixth inventions, the mesh body has the effect of preventing foreign matter from entering the cavern from the river or sea.

The eighth invention is characterized in that, in any of the first to seventh inventions, it has a plurality of pillars, and the tops of two adjacent pillars are connected to each other by a wire.
In the eighth invention, in addition to the effect of any one of the first to seventh inventions, the wire prevents people or vehicles from falling even when the distance between the posts is wide.

According to the first invention, there is no need to remove the support poles in advance even when it is predicted that the water level of a river or sea will rise, and there is no need to reinstall the support poles after the water level has dropped, thereby saving the time and cost that would previously have been required for such work. Furthermore, because there is no risk of the support poles being damaged even in the event of overflow, they can be used for a long period of time.

According to the second invention, the float is more likely to move downward along the inclined surface due to its own weight, which in addition to the effect of the first invention, provides the effect of ensuring that the support pole can be raised reliably.

The downward force applied from the support to the support pole changes depending on the buoyancy applied to the float, and the buoyancy applied to the float changes depending on the float's specific gravity. According to the third invention, in addition to the effect of the second invention, the downward force applied from the support to the support pole can be easily adjusted by the simple operation of changing the amount of liquid stored in the hollow container.

The fourth invention achieves the same effect as any of the first to third inventions, but also reduces manufacturing costs because a common connector can be used for posts of various sizes.

The fifth invention has the effect of any one of the first to fourth inventions, plus the effect that the function of the guide means to hold the support device in a swingable manner can be achieved with an inexpensive mechanism.

The sixth invention has the effect of any one of the first to fourth inventions, but also has the effect of realizing the function of the guide means to swingably hold the support device at low cost, similar to the fifth invention, using a mechanism separate from that of the fifth invention.

If foreign objects such as fish or debris enter the horizontal tunnel from the river or sea through the water intake hole and get caught in the gap between the float and the inclined surface or between the support device and the guide means, the operation of the support device will be hindered, and the mechanism for raising and lowering the support pole will likely malfunction. In contrast, the seventh invention eliminates the risk of foreign objects entering the horizontal tunnel from the river or sea, and thus achieves the effect of any of the first through sixth inventions, as well as the effect of making the mechanism for raising and lowering the support pole less susceptible to malfunction.

The eighth invention, in addition to the effects of any one of the first to seventh inventions, has the effect of reducing manufacturing and installation costs by increasing the spacing between the posts and reducing the number of posts.

1A is a diagram showing a location where a fall prevention fence according to a first embodiment of the present invention is to be installed, and FIG. 1B is a cross-sectional view taken along line AA in FIG. 1A. 1A is a cross-sectional view taken along the line BB in FIG. 1A, and FIGS. 1B and 1C are external perspective views of the support and bearing portion shown in FIG. 1A, respectively. (a) and (b) are external perspective views showing the first connector, the second connector, and the shaft body installed on the connector, and the external perspective view of the connector only, respectively; (c) is an external perspective view showing the first connector and the second connector connected via the shaft body; and (d) and (e) are external perspective views of the first connector and the second connector, respectively. 2A is a perspective view of the outer appearance of the guide member, and FIG. 2B is an enlarged view of the portion surrounded by the dashed line in FIG. 2A. 1(a) and 1(b) are diagrams showing how the posts of the fall prevention fence shown in FIG. 1(b) move up and down in accordance with changes in the water level of the river. 10A and 10B are cross-sectional views showing the structure of a fall prevention fence according to a second embodiment of the present invention. 6(a) to 6(c) are external perspective views of the support tool, the rotating tool, and the rotating tool holding member shown in FIG. 6(a) and FIG. 6(b), respectively, and FIG. 6(d) is an enlarged view of the part surrounded by the dashed line in FIG. 6(b). 6A and 6B are diagrams showing how the posts of the fall prevention fence shown in FIG. 6A move up and down in accordance with changes in the water level of the river. FIG. 1A is a diagram showing an example of a location where a conventional fall prevention fence is installed, and FIG. 1B is a diagram showing the fall prevention fence in FIG. 1A as viewed from the river side.

The fall prevention fence of the present invention is installed on river or sea embankments to prevent people and vehicles from falling. Its specific structure and the associated actions and effects are described in detail below with reference to Figures 1 to 8. While the examples use an embankment built on a river as an example, the actions and effects described below are similarly achieved when the fall prevention fence of the present invention is applied to an embankment built on the sea. Furthermore, since the posts are used while loosely inserted into the post insertion holes formed parallel to the vertical direction, and the support device is designed to swing within a range that prevents it from being upside down, this specification uses terms such as upper and lower, upper and lower, upper end and lower end, etc., assuming such conditions.

Figure 1(a) shows the location where a fall prevention fence according to a first embodiment of the present invention is installed, and Figure 1(b) is a cross-sectional view taken along line A-A in Figure 1(a). Figure 2(a) is a cross-sectional view taken along line B-B in Figure 1(a), and Figures 2(b) and 2(c) are external perspective views of the support and bearing unit shown in Figure 2(a), respectively. Figures 3(a) and 3(b) are external perspective views of the first connector, the second connector, and the shaft body installed on the coupling, and the coupling only, respectively. Figure 3(c) is an external perspective view of the first connector and the second connector connected via the shaft body. Figures 3(d) and 3(e) are external perspective views of the first connector and the second connector, respectively. Figure 4(a) is an external perspective view of the guide member, and Figure 4(b) is an enlarged view of the area surrounded by the dashed line in Figure 2(a).
In Fig. 1(a), only one representative support pillar is labeled with a reference number, and the other pillars are omitted. Fig. 1(b) also shows a schematic representation of the hollow container constituting the trolley, with water approximately 80% filled inside. Figs. 3(a) and 3(b) show the connector with the underside facing upward, and Fig. 4(a) shows part of the support with a dashed line. Components already described using Fig. 9 are labeled with the same reference numbers, and their description will be omitted where appropriate.

1(a) and 1(b), a fall prevention fence 1a includes a plurality of posts 2 installed on a levee 53 installed along a river 55, connectors 3 installed at the lower ends 2a of the posts 2 (see FIG. 2(a)), a pair of rod-shaped supports 4, 4 whose upper ends 4a are swingably held by the connectors 3, a cart 5 to which the lower ends 4b of the supports 4 are swingably connected, guide means 6a that swingably hold the supports 4, a horizontal hole 7 formed inside the levee 53 and in which the connectors 3, supports 4, cart 5, and guide means 6a are installed, and a wire 52 (see FIG. 9(b)) that connects the upper parts of two adjacent posts 2, 2 to each other. The levee 53 also has a water intake hole 8 inside the horizontal hole 7 to allow water from the river 55 to flow into the interior, and the cart 5 is installed on a slope 7a provided at the bottom of the horizontal hole 7.
In this way, in the fall prevention fence 1a, the tops of two adjacent posts 2 out of the multiple posts 2 are connected to each other by the wire 52, so even if there is a wide gap between the posts 2, the wire 52 prevents people and vehicles from falling. Therefore, in the fall prevention fence 1a, by widening the gap between the posts 2 and reducing the number of posts 2, it is possible to reduce manufacturing and installation costs.

The pair of supports 4, 4 are installed inside the horizontal hole 7 at an incline with respect to the vertical direction, and the inclined surface 7a is inclined in a direction such that when the cart 5 moves downward along the inclined surface 7a due to its own weight, the pair of supports 4, 4 swing in a direction that reduces the angle they form with the vertical direction.
Furthermore, since the trolley 5 is composed of an airtight, approximately rectangular parallelepiped hollow container 5a and wheels 5b attached to the bottom of the hollow container 5a, the overall specific gravity changes when water is stored inside the hollow container 5a. In other words, the trolley 5 is structured so that the overall specific gravity can be made less than 1 by leaving air inside the hollow container 5a rather than completely filling it with water. For example, if water flows into the horizontal hole 7 through the water intake hole 8 as the water level of the river 55 rises and the horizontal hole 7 is filled with water, if the specific gravity of the trolley 5 is less than 1, the trolley 5 will float up due to the action of buoyancy. As a result, the pair of supports 4, 4 will swing in a direction that increases the angle they form with the vertical as the trolley 5 rises, as described below.

As shown in Figure 2(a), the support posts 2 are inserted parallel to the vertical direction from the top surface 53a of the embankment 53, known as the top edge, into support post insertion holes 9 formed so that their lower ends open at the top of the horizontal hole 7, and a mesh structure 10 is installed at the open end 8a of the water intake hole 8 facing the river 55. If foreign objects such as fish or garbage enter the horizontal hole 7 from the river or sea through the water intake hole 8 and get into the gap between the cart 5 and the inclined surface 7a or between the support device 4 and the guide means 6a, the operation of the support device 4 will be hindered, and the mechanism for raising and lowering the support post 2 will likely malfunction. In contrast, in the fall prevention fence 1a, the mesh structure 10 prevents foreign objects from entering the horizontal hole 7 from the river or sea, making the mechanism for raising and lowering the support post 2 less likely to malfunction.
As shown in Figure 2(b), the support 4 is made of a long round bar, and a pair of cylindrical protrusions 4c, 4c are provided symmetrically on the side surface of the lower end 4b, sandwiching the central axis of the support 4. Furthermore, a pair of cylindrical convex portions 4d, 4d are provided symmetrically on the side surface between the upper end 4a and the lower end 4b, sandwiching the central axis of the support 4. The cylindrical axes of the pair of protrusions 4c, 4c and the pair of convex upper portions 4d, 4d are parallel. In other words, the support 4 is structured so that it can rotate in the same plane when the pair of protrusions 4c, 4c and the pair of convex upper portions 4d, 4d are used as rotation axes, respectively.
2(c), a pair of bearings 5d, 5d that rotatably hold the pair of protrusions 4c, 4c of the support 4 are provided on the opposing side surfaces 5c, 5c of the pair of carriages 5, 5. In other words, the lower end 4b of the support 4 is swingably connected to the carriage 5 by the pair of bearings 5d, 5d, as described above.

As shown in Figure 3(a), the rectangular parallelepiped connector 3 has the first connector 11, second connector 12, and shaft 13 installed inside, and its top surface 3a is joined to the bottom end 2a of the support 2 (see Figure 2(a)). As shown in Figure 3(b), the connector 3 is box-shaped with an open bottom surface 3b. A pair of parallel side surfaces 3c, 3c each have a circular through-hole 3e through which the cylindrical shaft 13 is inserted. A pair of side surfaces 3d, 3d perpendicular to side surface 3c each have a groove 3f formed from the bottom surface 3b, into which the connecting portion 11a of the first connector 11 and the connecting portion 12a of the second connecting portion 12 can be placed.

3(c) to 3(e), the first connector 11 comprises a cylindrical connector 11a into which the upper end 4a of the support 4 is inserted, and an annular bearing 11b into which the shaft 13 is inserted and one end of the connector 11a is attached to the side surface. The second connector 12 comprises a cylindrical connector 12a into which the upper end 4a of the support 4 is inserted, and a pair of bearings 12b, 12b that are coaxially arranged to allow communication with the shaft 13 and one end of the connector 12a is attached to the side surface via a mounting fixture 12c. The central axis of the connector 11a is perpendicular to the central axis of the bearing 11b, and the central axis of the connector 12a is perpendicular to the central axes of the bearings 12b, 12b.
Furthermore, as shown in Fig. 3(c), the pair of bearing portions 12b, 12b of the second connector 12 can communicate with the shaft body 13 while being arranged on both sides of the bearing portion 11b of the first connector 11. Therefore, when the first connector 11 and the second connector 12 are installed inside the coupling device 3 as shown in Fig. 3(a), and the shaft body 13 is communicated with the pair of through holes 3e, 3e, the bearing portion 11b, and the pair of bearing portions 12b, 12b, the first connector 11 and the second connector 12 are fixed to the coupling device 3 while remaining swingably connected via the shaft body 13.

4(a) and 4(b), the guide means 6a is made up of a pair of guide members 14, 14 that are parallel to the horizontal direction and are installed on both sides of the support tool 4 so as to be able to engage with the pair of convex portions 4d, 4d, and a pair of fixing members 15, 15 for fixing both ends of the pair of guide members 14, 14 to the inner wall surface of the horizontal hole 7. The pair of guide members 14, 14 are installed at a height such that their lower sides 14a come into contact with the pair of convex portions 4d, 4d of the support tool 4 when water from the river 55 is not flowing into the horizontal hole 7, as shown in FIG.
In this case, the pair of convex portions 4d, 4d of the support device 4 are engaged with the pair of guide members 14, 14 of the guide means 6a, so that horizontal movement is permitted but upward movement is restricted. In other words, the pair of support devices 4, 4 are configured to be able to swing about the shaft 13 (see FIG. 3(c)) connecting the first connector 11 (see FIG. 3(d)) and the second connector 12 (see FIG. 3(e)) while the pair of convex portions 4d, 4d move horizontally along the pair of guide members 14, 14 of the guide means 6a as shown by arrow D in FIG. 4(a).

5(a) and 5(b) are diagrams showing how the support posts 2 of the fall prevention fence 1a move up and down in accordance with changes in the water level of the river 55. FIG.
When the water level of the river 55 has not reached the height of the opening end 8a of the water intake hole 8, no water flows into the horizontal hole 7 from the water intake hole 8, and as shown in Figure 1(b), the wheels 5b of the cart 5 are in contact with the inclined surface 7a of the horizontal hole 7. In this case, the support pillar 2 is supported from below by a pair of supports 4, 4, and therefore will not descend on its own.
On the other hand, when the river 55 rises due to heavy rain or the like and the water level exceeds the height of the opening end 8a of the water intake hole 8, the water of the river 55 flows into the inside of the horizontal hole 7 through the water intake hole 8. At this time, if the specific gravity of the carriage 5 is set to be less than 1, buoyancy will be generated in the carriage 5 from the time when the water level inside the horizontal hole 7 begins to exceed the height of the carriage 5. As the water level rises further, the two carriages 5 begin to float up, and accordingly, the pair of supports 4, 4 swing in a direction in which the angle they form with each other increases (i.e., in a direction in which the angle they form with the vertical direction increases) around the shaft 13 (see FIG. 3(c)) connecting the first connector 11 (see FIG. 3(d)) and the second connector 12 (see FIG. 3(e)) as the pair of convex portions 4d, 4d (see FIG. 2(b)) move horizontally in directions away from each other along the pair of guide members 14, 14 (see FIG. 4(a)) of the guide means 6a. At this time, the upper ends 4a of the pair of supports 4 move downward because the guide members 14 of the guide means 6a restrict the pair of convex portions 4d from moving upward. The lower end 2a of the support 2 is then pulled downward by the connector 3 to which the upper ends 4a of the pair of supports 4 are connected via the first connector 11, second connector 12, and shaft 13. As a result, the support 2 moves downward as shown by arrow E in Figure 5(a).

When the water level of the river 55 drops from the state shown in FIG. 5( a), the water inside the horizontal hole 7 is discharged through the water intake hole 8 and out of the embankment 53. The two carts 5 then descend as the water level inside the horizontal hole 7 drops, and when the wheels 5b touch the inclined surface 7a of the horizontal hole 7, they begin to move downward along the inclined surface 7a due to their own weight. Accordingly, the pair of supports 4, 4 swing in a direction that reduces the angle they form with each other (i.e., the angle with the vertical direction) around the shaft 13 (see FIG. 3( c)) connecting the first connector 11 (see FIG. 3( d)) and the second connector 12 (see FIG. 3( e)). As a result, the upper ends 4a, 4a of the pair of supports 4, 4 move upward, and the lower ends 2a of the support columns 2 receive an upward force from the pair of supports 4, 4 via the connector 3. As a result, the support column 2 rises as shown by the arrow F in FIG. 5(b).
In this way, in the fall prevention fence 1a, the support posts 2 descend as the water level of the river 55 rises, and most of them are stored inside the levee 53, so there is no need to remove the support posts 2 in advance even if it is predicted that the water level of the river 55 will rise. Furthermore, even if the river overflows due to heavy rain or the like, there is no risk of damage to the support posts 2 because most of them are stored inside the levee 53. Furthermore, the wires 52 (see Figure 9(b)) attached to the tops of the support posts 2 will not be damaged in the first place even if they are not removed.
Furthermore, when the water level of the river 55 drops, the support 2 rises accordingly, and the part that was stored inside the embankment 53 appears above ground, so there is no need to install the support 2 again in the fall prevention fence 1a.
In other words, the fall prevention fence 1a of the present invention can save the time and expense required for the removal and restoration of posts that were necessary with conventional fall prevention fences.In addition, since there is no risk of the posts being damaged by overflowing water, it can be used for a long period of time.

Figures 6(a) and 6(b) are cross-sectional views showing the structure of a fall prevention fence according to a second embodiment of the present invention, and correspond to Figures 1(b) and 2(a), respectively, which show fall prevention fence 1a. Also, Figures 7(a) to 7(c) are external perspective views of the support tool, rotating tool, and rotating tool holding member shown in Figures 6(a) and 6(b), respectively, and Figure 7(d) is an enlarged view of the area surrounded by the dashed line in Figure 6(b). Note that part of the support tool is indicated by a dashed line in Figure 7(c). Components already described using Figures 1 to 5 and 9 are designated by the same reference numerals, and their description will be omitted where appropriate.

As shown in Figures 6(a) and 6(b), the fall prevention fence 1b has a structure in which the support member 16 and guide means 6b are provided instead of the support member 4 and guide means 6a of the fall prevention fence 1a.
That is, in the fall prevention fence 1b, a pair of supports 16, 16 whose upper ends 16a are swingably held by the connector 3 and whose lower ends 16b have the carriage 5 swingably connected to them via bearings 5d (see FIG. 2(c)) are installed inside the horizontal tunnel 7 in a state inclined with respect to the vertical direction, and so as to swing in a direction that reduces the angle with the vertical direction when the carriage 5 moves downward along the inclined surface 7a of the horizontal tunnel 7 due to its own weight. In addition, the pair of supports 16, 16 are swingably held by guide means 6b fixed to the inner wall surface of the horizontal tunnel 7.

As shown in Figure 7(a), the support 16 is made of a long round bar, and a pair of cylindrical protrusions 16c, 16c are provided symmetrically on the side of the lower end 16b, sandwiching the central axis of the support 16. The pair of protrusions 16c, 16c are held swingably by a pair of bearings 5d, 5d (see Figure 2(c)) provided on the side surface 5c of the bogie 5 (see Figure 2(c)).
As shown in Figures 7(b) to 7(d), the guide means 6b comprises a rotating tool 17 having a pair of convex portions 17b, 17b that serve as rotation axes and are arranged symmetrically on either side of the cylindrical body 17a on the side of the cylindrical body 17a into which the support tool 16 is loosely inserted, and that protrude in a direction perpendicular to the longitudinal direction of the cylindrical body 17a, and a rotating tool holding member 18 that rotatably holds the rotating tool 17.
The rotating tool holding member 18 is parallel to the horizontal direction and is provided with bearing portions 18b that rotatably hold the convex portions 17b of the rotating tool 17, and is composed of a pair of bearing members 18a, 18a installed on both sides of the rotating tool 17 so that the pair of convex portions 17b, 17b can be simultaneously held by the respective bearing portions 18b, and a pair of fixing members 18c, 18c for fixing the pair of bearing members 18a, 18a to the inner wall surface of the horizontal hole 7. Note that, as shown in Figure 6(a), the two bearing portions 18b are provided on the bearing member 18a so that the pair of supports 16, 16 can be loosely inserted into the cylindrical bodies 17a of the pair of rotating tools 17 simultaneously when water from the river 55 is not flowing into the horizontal hole 7.
In this case, by loosely inserting the support tool 16 into the cylindrical body 17a of the rotating tool 17, the support tool 16 is allowed to move in the longitudinal direction of the cylindrical body 17a, and is held together with the rotating tool 17 in a rotatable state around the convex portion 17b as a rotation axis by the bearing portion 18b of the rotating tool holding member 18. In other words, the pair of support tools 16, 16 are structured to be able to swing around the shaft 13 (see FIG. 3(c)) connecting the first connector 11 (see FIG. 3(d)) and the second connector 12 (see FIG. 3(e)) while moving inside the cylindrical body 17a of the rotating tool 17 as shown by arrow G in FIG. 7(c).

8(a) and 8(b) are diagrams showing how the support posts 2 of the fall prevention fence 1b move up and down in accordance with changes in the water level of the river 55. FIG.
When the water level of the river 55 has not reached the height of the opening end 8a of the water intake hole 8, no water flows into the horizontal hole 7 from the water intake hole 8, and as shown in Figure 6(a), the wheels 5b of the cart 5 are in contact with the inclined surface 7a of the horizontal hole 7. In this case, the support pillar 2 is supported from below by a pair of supports 16, 16, and therefore will not descend on its own.
On the other hand, if the river 55 rises due to heavy rain or the like and the water level exceeds the height of the open end 8a of the water intake hole 8, the water from the river 55 will flow through the water intake hole 8 into the inside of the horizontal hole 7. At this time, if the specific gravity of the carriages 5 is set to be less than 1, buoyancy will be generated in the carriages 5 when the water level inside the horizontal hole 7 begins to exceed the height of the carriages 5, and the two carriages 5 will begin to float. As the two carriages 5 float, the pair of supports 16, 16 will move in their longitudinal direction inside the cylindrical body 17a of the rotating tool 17, and will swing in a direction in which the angle they form with each other increases (i.e., in a direction in which the angle they form with the vertical direction increases) around the shaft 13 (see FIG. 3(c)) that connects the first connector 11 (see FIG. 3(d)) and the second connector 12 (see FIG. 3(e)). As a result, the upper ends 16a, 16a of the pair of supports 16, 16 move downward, and the lower end 2a of the support 2 is pulled downward by the connector 3 to which the upper ends 16a, 16a of the pair of supports 16, 16 are connected via the first connector 11, the second connector 12, and the shaft 13. As a result, the support 2 descends as shown by arrow H in Figure 8(a).

When the water level of the river 55 drops from the state shown in Figure 8(a), the water inside the horizontal hole 7 is discharged outside the embankment 53 through the water intake hole 8. Then, the two carts 5 descend as the water level inside the horizontal hole 7 drops, and when the wheels 5b touch the inclined surface 7a of the horizontal hole 7, they begin to move downward along the inclined surface 7a due to their own weight. Accordingly, the pair of supports 16, 16 move longitudinally inside the cylindrical body 17a of the rotating device 17, and swing in a direction in which the angle they form with each other decreases (i.e., in a direction in which the angle they form with the vertical direction decreases) around the shaft 13 (see Figure 3(c)) that connects the first connector 11 (see Figure 3(d)) and the second connector 12 (see Figure 3(e)). As a result, the upper ends 16a, 16a of the pair of supports 16, 16 move upward, and the lower end 2a of the support 2 receives an upward force from the pair of supports 16, 16 via the connecting device 3, causing the support 2 to rise as shown by arrow I in Figure 6 (b).
In this way, in the fall prevention fence 1b, the posts 2 descend as the water level of the river 55 rises, so there is no need to remove the posts 2 in advance when it is predicted that the water level of the river 55 will rise. Furthermore, even if the river overflows due to heavy rain or the like, there is no risk of damage to the posts 2 because most of the posts 2 are stored inside the levee 53. Furthermore, as mentioned above, there is no risk of damage to the wires 52 (see Figure 9(b)) attached to the tops of the posts 2 even if they are not removed.
Furthermore, since the support posts 2 rise as the water level of the river 55 drops, there is no need to reinstall the support posts 2 in the fall prevention fence 1b.
In other words, the fall prevention fence 1b of the present invention, unlike conventional fall prevention fences, does not require the removal and restoration of posts, thereby saving the time and cost that would previously have been required for such work.

The fall prevention fence of the present invention is not limited to the structure shown in the above-described embodiment. For example, instead of the trolley 5, a mechanism in which wheels 5b are attached to the lower end 4b of the support 4 or the lower end 16b of the support 16 so that they can roll along the inclined surface 7a can be used as a float. With such a structure, the float's action of moving downward along the inclined surface 7a due to its own weight and the resulting effect can be similarly achieved. However, in this case, the specific gravity of the float cannot be changed. The downward force applied to the support pole 2 from the support 4 or the support 16 varies depending on the buoyancy applied to the float, and the buoyancy applied to the float varies depending on the specific gravity of the float. However, in the fall prevention fences 1a and 1b, the specific gravity of the trolley 5 functioning as a float can be easily adjusted by simply changing the amount of water stored in the hollow container 5a, thereby easily adjusting the force applied to the support pole 2 from the support 4 or the support 16.
It is also possible to use a structure in which the upper ends 4a of the supports 4 and the upper ends 16a of the supports 16 are swingably connected to the lower ends 2a of the posts 2 without using the connectors 3. However, if there are multiple posts 2 of different dimensions, it is necessary to process each post 2 to provide a mechanism for swingably holding the upper ends 4a of the supports 4 and the upper ends 16a of the supports 16. In contrast, with the fall prevention fences 1a and 1b, a common connector 3 can be used for posts 2 of various dimensions, which has the advantage of reducing manufacturing costs.

This invention can be used when it is necessary to install fences on river or sea embankments to prevent people or vehicles from falling off.

DESCRIPTION OF SYMBOLS 1a, 1b...Fall prevention fence 2...Support 2a...Lower end 3...Connecting device 3a...Upper surface 3b...Lower surface 3c, 3d...Side surface 3e...Through hole 3f...Groove 4...Support device 4a...Upper end 4b...Lower end 4c...Projection portion 4d...Convex portion 5...Cart 5a...Hollow container 5b...Wheel 5c...Side surface 5d...Bearing portion 6a, 6b...Guide means 7...Horizontal hole 7a...Inclined surface 8...Water intake hole 8a...Open end 9...Support insertion hole 10...Reticulated body 11...First connecting device 11a...Connecting portion 11b...Bearing portion 12...Second connecting device 12a...Connecting portion 12b...Bearing portion 12c...Mounting device 13...Shaft 14...Guide member 14a...Underside 15...Fixing member 16...Support device 16a... Upper end 16b... Lower end 16c... Protrusion 17... Rotating tool 17a... Cylindrical body 17b... Convex portion 18... Rotating tool holding member 18a... Bearing member 18b... Bearing portion 18c... Fixing member 50... Fall prevention fence 51... Support 52... Wire 53... Embankment 53a... Upper surface 54... Discharge outlet 55... River 56... Discharge channel

Claims (8)

A fall prevention fence installed on river or sea banks,
a horizontal hole formed inside the bank;
a support post insertion hole formed parallel to the vertical direction from the upper surface of the bank so that its lower end opens to the upper part of the horizontal hole;
A support pillar loosely inserted through the support pillar insertion hole;
a rod-shaped support whose upper end is swingably connected to the lower end of the support and which is installed inside the horizontal hole in a state inclined with respect to the vertical direction to support the support;
a float installed on an inclined surface provided at the bottom of the horizontal hole and connected to the lower end of the support;
and guide means fixed to the inner wall of the bank for swingably holding the support tool,
A water intake hole is provided at the bottom of the horizontal cavern to allow water from the river or the sea to flow into the interior,
The float has a specific gravity of less than 1 and is installed so as to be movable downward along the inclined surface by its own weight,
A fall prevention fence characterized in that the support device is installed so as to swing in a direction that reduces the angle it forms with the vertical direction as the float descends. A fall prevention fence as described in claim 1, characterized in that the float is equipped with wheels that are installed so that they can roll along the inclined surface. the float includes a hollow container provided with a bearing portion that rotatably holds the lower end of the support,
3. The fall prevention fence according to claim 2, wherein the wheels are rotatably attached to the hollow container. A fall prevention fence as described in any one of claims 1 to 3, characterized in that it is provided with a connecting device installed at the lower end of the support pole and swingably holding the upper end of the support device. the support has a convex portion serving as a rotation axis on a side surface between the upper end and the lower end,
A fall prevention fence as described in any one of claims 1 to 4, characterized in that the guide means consists of a guide member that engages with the upper surface of the convex portion to allow horizontal movement while restricting upward movement. a rotating tool provided on a side surface of a cylindrical body into which the support tool is loosely inserted, with a convex portion serving as a rotation axis protruding in a direction perpendicular to the longitudinal direction of the cylindrical body;
5. The fall prevention fence according to claim 1, wherein the guide means comprises a rotating tool holding member that rotatably holds the convex portion of the rotating tool. A fall prevention fence as described in any one of claims 1 to 6, characterized in that a mesh is installed at the open end of the water intake facing the river or the sea. 8. A fall prevention fence according to claim 1, comprising a plurality of the posts, the tops of two adjacent posts being connected to each other by a wire.