JPH041129B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a fender device for cushioning the impact of ships and floating structures in ports or oceans.

As shown in FIGS. 1 to 4, in the conventional fender a, the impact receiving part b has a solid square pyramid shape, and the supporting part c has a hollow square pyramid shape. As shown in FIG. 2, the support portion c has an inner and outer surface that are substantially parallel and have a uniform inclination.

Therefore, the mechanical phenomenon when a ship receives compressive force when coming alongside is as follows.

In Fig. 3, assuming that the thickness of the four sides d of the support section is td and the thickness of the four corner sections e is te, the moment of inertia Id of the four side sections d of the support section is td ⁴ , that is, the thickness of the plate thickness td. It is proportional to the fourth power, and the moment of inertia Ie of the four corners e is proportional to te ⁴ , that is, the fourth power of the plate thickness te.

By the way, when the compressive force P is applied, both the impact receiving part b and the supporting part c undergo elastic deformation while the compressive force P is relatively small, but as the compressive force P increases, the supporting part c undergoes buckling deformation. It will change to In this case, the buckling stress is σαEI, and the buckling stress is proportional to the moment of inertia of area Id and Ie, respectively. And te
＞td Therefore, the second moment of area Ie＞＞Id.

Therefore, compared to the four side portions d of the support portion, the four corner portions e are far less susceptible to buckling deformation. As a result, only the four side parts d forming the periphery undergo buckling deformation.

This buckling deformation is best caused by keeping the four corners e at right angles because the amount of displacement in the vicinity of the four corners e of the four sides d is small, as shown in FIG. 4. A deformed state in which one opposing member bulges outward and the other opposing member dents inward tends to occur, which causes a decrease in the amount of displacement.

In addition, since the cross section of the support part c is uniform, when buckling deformation occurs, the buckling stress σ of the support part c becomes almost the same as the buckling of a long column, and the buckling stress σ becomes EI/l ² . Proportionally, it is inversely proportional to the square of the length l of the support portion c.

Therefore, the stress drop at the transition point from the elastic deformation region to the buckling deformation region became significant.

The present invention relates to an improvement of a fender device that eliminates such drawbacks, and provides a fender device in which the small diameter side of a hollow tapered cylindrical body made of a rubber elastic body is used as an impact receiving part, and the large diameter side is used as a mounting end. In this step, the thickness of the cylindrical body is gradually increased from the mounting end side toward the impact receiving end side, and a groove is formed at a predetermined position on the impact receiving end side of the outer periphery of the cylindrical body. It is characterized by having one or both of its inner and outer surfaces in the form of a polygonal pyramid, and its purpose is to provide fenders with excellent cushioning properties that can provide a large amount of displacement and stable displacement. The point is that it provides

In the present invention, in the fender device in which the small diameter side of the hollow tapered cylindrical body made of a rubber elastic body is used as the impact receiving end and the large diameter side is used as the attachment end, as described above, the wall thickness of the cylindrical body is Since the wall thickness gradually increases from the mounting end to the impact-receiving end, the cross-sectional area from the midsection to the impact-receiving end is relatively large, and the compressive reaction force in the region where the amount of strain is relatively small (elastic deformation region) is reduced. increases. Note that the compression reaction force refers to a force that resists the compression force.

In addition, in the present invention, since the groove is formed at a predetermined position on the impact-receiving end side of the outer periphery of the cylindrical body, buckling deformation is likely to occur in the groove, and buckling reaction force (force that resists buckling load) ) is inversely proportional to the square of the column length l from the groove to the receiving end, and compared to a case where the shape is uniform from the mounting end to the receiving end. For those with a uniform shape, the column length from the mounting end to the impact receiving end is l), and can be dramatically increased. Therefore, together with the increase in compression reaction force in the elastic deformation region, the buckling reaction force can also be increased in the buckling deformation region, and the reaction in the transition region from the elastic deformation region to the buckling deformation region increases. It is possible to measure the increase in force.

Furthermore, in the present invention, since one or both of the inner and outer surfaces of the cylindrical body is made into a polygonal pyramid, when compressive force is applied, the entire surface of the pyramidal surface is deformed to bulge outward, resulting in a large displacement. This makes it a fender with excellent cushioning properties. Moreover, as described above, the entire surface of the pyramidal surface is deformed to bulge outward, resulting in stable deformation, and the compressive force can be evenly distributed to each part, so that stress concentration can be avoided.

Furthermore, in the present invention, since the cylindrical body is a polygonal pyramid, the moment of inertia I of area increases, and buckling stress can be increased.

An embodiment of the present invention illustrated in FIGS. 5 to 7 will be described below.

The fender 1 made of a rubber elastic body has an impact receiving part 2
, a mounting part 3 parallel to the mounting part 3, and a support part 4 which is erected with an inward slope from the mounting part 3 toward the impact receiving part 2, and the support part 4 is shown in FIG. As shown in FIGS. 6 to 6, the interior is hollow and both the inner and outer surfaces are formed with octagonal pyramidal surfaces.

The outer surface of the fender 1 is defined by the height of the mounting portion 3, assuming that the height from the bottom surface of the mounting portion 3 to the top surface of the impact receiving portion 2 is H.
It is formed with a predetermined uniform inclination θ ₁ (9°±2° with respect to the vertical line) inward toward the lower part 5 of the impact receiving part, and from the lower part 5 of the impact receiving part to the upper surface of the upper surface of the impact receiving part 2. is formed vertically. Note that the position of the lower part 5 of the impact receiving part is the same as that of the impact receiving part 2.
Approximately 0.1H from the top surface. Further, an upper groove 6 is formed around the entire circumference at a position approximately 0.2H from the upper surface of the impact receiving part 2, and the upper groove 6 is formed in the shape of a semicircular arc, and its radius is within the range of 0.01 to 0.015H. It is set to a predetermined size. Furthermore, it is omitted from the bottom of the mounting part 3.
A lower groove 7 is formed around the entire circumference at a position within a range of 0.1H, and the lower groove 7 is also set to have the same shape and dimensions as the upper groove 6.

On the other hand, the inner surface of the fender 1 has a predetermined uniform inclination angle θ ₂ (with respect to the vertical line θ ₁ +3 to 4゜゜), and the mid-abdominal part 8
It is formed to have an inclination angle θ ₃ (θ ₁ +4 to 5° with respect to the vertical line) that is inclined further inwardly than the above-mentioned inclination angle θ ₂ toward the lower impact-receiving end portion 9 . The portion from the lower end portion 9 of the impact receiving portion to the upper surface of the impact receiving portion 2 is vertically formed. As shown in FIG. 6, it is preferable to add a radius to the inner surface in terms of durability, and in terms of compression performance, even if the wall thickness at the four corners is too thick, the amount of deformation will be small. Therefore, R
If the range is too small, the durability will be poor, and if it is too large, the displacement will be insufficient as mentioned above.
The appropriate range is 0.08H≦R≦0.12H.

Therefore, the fender 1 has a higher impact receiving part 2 than an attachment part 3.
It will gradually become thicker as it approaches.

Since the embodiment shown in FIGS. 5 and 6 is constructed as described above, when an impact load from a ship or the like is applied to the fender 1, the fender 1 will be damaged as shown in FIG. The device 1 will be deformed. That is, FIG. 7 illustrates the deformed state of the fender 1. If the amount of displacement of the fender 1 when subjected to a compressive load is ΔH, and the strain ε is expressed as a percentage, then ε=△H/H×100(%), ε=0 for figure A, ε=10 for figure B, ε=20 for figure C, ε for figure D.
= 30, E diagram is ε = 40, F diagram is ε = 50, G diagram is ε =
Each represents 55 states. As is clear from FIG. 7, while the strain is extremely small (ε=10), the upper grooves 6 do not collapse and come into close contact with each other;
When the strain exceeds a predetermined value (ε=20 or more shown in diagram C),
The upper grooves 6 are crushed and come into close contact with each other. At this time, the support portion 8 is deformed to swell outward.

If the strain is further increased, as shown in Figures E and F, the supporting part 4 on the side of the mounting part 3 from the upper groove 6 will further bulge outward, while the receiving part 2 above the upper groove 6 will expand outward. Since the deformation does not bulge in the direction, buckling gradually begins to occur at the upper groove 6, and the impact receiving part 2 above the upper groove 6 gradually bulges outward as the supporting part 4.
It becomes deformed by sinking inwards. When the strain ε=55 as shown in Figure G, the outer wall of the support portion 4 and the impact receiving portion 2 come into contact. At this time, since the area from the upper groove 6 to the lower part 5 of the impact receiving part is formed at a predetermined inclination angle θ ₁ , it functions to increase the reaction force against the above-mentioned compressive load. That is, the inclined portion I between the lower part 5 of the impact receiving part and the upper groove 6 becomes perpendicular to the impact receiving part 2 during the process of being compressively deformed. In the process of applying such forced deformation, the reaction force increases as a reaction. If the slope I is vertical, the compression reaction force will be generated only by the bending of the impact receiving part 2, so although the compression reaction force will decrease, the deformation will be stabilized.

As described above, in this embodiment, since the support part 4 is formed to be gradually thicker from the attachment part 3 toward the impact receiving part 2, the cross-sectional area from the vicinity of the midsection 8 of the support part to the impact receiving part 2 is comparatively large. The compressive reaction force increases greatly in a region (elastic deformation region) where the amount of strain is large and the amount of strain is relatively small (elastic deformation region).

In addition, in this embodiment, an upper groove 6 is provided on the outer periphery of the fender 1.
Since buckling deformation occurs at the groove 6, the column length from the groove 6 to the mounting portion 3 is reduced to l.
Therefore, the column length l can be shortened, and the buckling reaction force can be extremely increased. Therefore, it is possible to increase the buckling reaction force in the buckling deformation area as well as increasing the compression reaction force in the elastic deformation area described above.

Furthermore, in this embodiment, since the support portion 4 is made of an octagonal pyramid, the entire surface of the pyramid is deformed to bulge outward as shown in FIG. It is an excellent fender. Moreover, this stable deformation allows compressive force to be uniformly distributed to each part, thereby avoiding stress concentration.

Furthermore, in this embodiment, since the lower groove 7 is provided on the outer periphery near the attachment part 3, when compressive force is applied, the lower groove 7 collapses and comes into close contact with each other, and the amount of strain near the lower groove 7 is reduced by the inner surface. The difference in the amount of strain between the inner and outer surfaces of the support portion 4 causes the outer surface of the support portion 4 to incline outward, and from this point as well, the entire pyramidal surface is deformed to bulge outward. I can do it.

In the embodiments shown in FIGS. 4 to 7, the inner surfaces of the pyramidal surfaces are connected by straight lines, but as shown in FIGS. 8 to 9, the four sides 10 of the inner surfaces of the pyramidal surfaces are connected by straight lines. It may also be swollen inward to form a circular arc shape. In this way, the compression reaction force can be further increased.

Alternatively, as shown in FIGS. 10 to 11, the outer surface of the support portion 4 may be swollen to form a circular arc shape. In this way, the neutral axis Y-Y will curve outward, and will inevitably deform outward when a compressive force is applied.

In the embodiments illustrated in FIGS. 4 to 11,
Although the flange was integrally formed on the support portion 2 and protruded outward from the rubber body, the flange may be omitted as shown in FIG. 12. In this case, the iron plate 11 may be embedded in the support part 2, and the iron plate 11 may be flush with the outer wall of the impact receiving part 2, or may be completely buried within the impact receiving part 2. Then, a cap nut 12 is integrally fixed to the iron plate 11, or a bolt is firmly fixed thereto, and an impact receiving plate (not shown) is attached thereto.

In this way, in the embodiment shown in Fig. 12, since the flange is removed, the flange does not come into contact with the bulging rubber body, so the compression reaction force does not increase suddenly, and the contact of the ship is prevented. Improves cushioning properties during porttime, etc.

[Brief explanation of drawings]

Fig. 1 is a plan view showing a conventional fender, Fig. 2 is a cross-sectional side view thereof, Fig. 3 is a cross-sectional view taken along the - line, and Fig. 4 is a plan view illustrating its compressed state. 5 is a cross-sectional side view illustrating one embodiment of the present invention, FIG. 6 is a sectional view taken along the - line, FIG. 7 is an explanatory diagram illustrating its compressed state, and FIG. The figure is a cross-sectional side view illustrating another embodiment according to the present invention, FIG. 9 is a cross-sectional view taken along the - line, FIG. 10 is a cross-sectional side view of still another embodiment, and FIG. That-
FIG. 12 is a cross-sectional view taken along a line, and FIG. 12 is a cross-sectional side view of yet another embodiment. 1... fender device, 2... impact receiving part, 3... mounting part, 4...
Support part, 5... lower part of impact receiving part, 6... upper groove, 7... lower groove,
8... Central restoration part of the support part, 9... Lower end of the impact receiving part, 10... Four side parts, 11... Iron plate, 12... Cap nut.

Claims (1)

[Claims] 1. In a fender device in which the small diameter side of a hollow tapered cylindrical body made of a rubber elastic body is the impact receiving end and the large diameter side is the mounting end, the wall thickness of the cylindrical body is increased from the mounting end to the impact receiving end. The thickness gradually increases toward the side, a groove is formed at a predetermined position on the impact-receiving end side of the outer periphery of the cylindrical body, and one or both of the inner and outer surfaces of the cylindrical body are formed into a polygonal pyramid. A fender device featuring: