US3690280A

US3690280A - Fender for large ship

Info

Publication number: US3690280A
Application number: US71722A
Authority: US
Inventors: Jiro Narabu
Original assignee: SEIBU GOMU KAGUKU KK
Current assignee: SEIBU GOMU KAGUKU KK
Priority date: 1970-09-14
Filing date: 1970-09-14
Publication date: 1972-09-12
Anticipated expiration: 1989-09-12

Abstract

In a rectangular tubular fender for large ship, made of elastic material and composed of a buffer, a fixture and two supports provided between said buffer and said fixture, the present invention contemplates an improvement therein wherein the exterior surfaces of said supports being made parallel to each other, the interior surfaces of said supports being flat and parallel to said exterior surfaces in the middle portion, the adjacent parts of said middle portion to said buffer and said fixture being curved, and the junctions between said curved portion and said buffer or fixture being depressed with a notch.

Description

[22] Filed:

Narabu Sept. 12, 1972 [54] FENDER FOR LARGE SHIP [72] Inventor: Jiro Narabu,Tokyo,Japan [73] Assignee: Seibu Gomukogaku Kogyo Kabru- V .shiki Ke sha, 0 51 9?! pan Sept. 14, 1970 21 Appl. No.: 71,722

Primary Examiner-Milton Buchler Assistant Examiner-Gregory W. OConnor Attorney-George B. Oujevolk [57] ABSTRACT In a rectangular tubular fender for large ship, made of elastic material and composed of a buffer, a fixture and two supports provided between said buffer and said fixture, the present invention contemplates an improvement therein wherein the exterior surfaces of said supports being made parallel to each other, the interior surfaces of said supports being flat and parallel to said exterior surfaces in the middle portion, the adjacent parts of said middle portion to said buffer and said fixture being curved, and the junctions between said curved portion and said buffer or fixture being depressed with a notch.

1 Claim, 8 Drawing Figures [52] U.S. Cl ..ll4/2l9 [51] Int. Cl. ..B63b 21/00 [58] Field ofSearch ..l14/2l9 [56] References Cited UNITED STATES PATENTS 3,507,123 4/1970 Miura ..l14/219 3,533,242 10/1970 Narabu, ..1 1.4/219 X 3,418,815 12/1968 Kurnazawa ..1 14/219 X mmrmsirlzmz 3.690.280

SHEET 2 [1F 2 FIG. 5 FIG. 4

2 L/m'a Mmly INVEA TOR.

FENDER FOR LARGE SHIP BACKGROUND OF THE INVENTION The present invention relates to a fender to be fitted to quays, etc., for cushioning a large ship.

BRIEF DESCRIPTION OF THE PRIOR ART SUMMARY OF THE INVENTION The objective of the present invention is to offer a fender with great energy absorption inwhich only the displacement increases, without the reaction being increased under shock; Broadly stated, in a rectangular tubular fender for a large ship, made of elastic material and composed of a buffer, a fixture, and two supports provided between said' buffer and said fixture, the present invention contemplates an improvement therein wherein the exterior surfaces of said supports being made parallel to each other, the interior surfaces of said supports being flat and parallel to said. exterior surfaces in the middle portion, the adjacentparts of said middle portion to said buffer and said fixture is curved, and the junctions between said curved portion and said buffer or fixture being depressed with a notch. Other objectives of this invention will be apparent by reading the description of the following embodiment with reference to the accompanying drawings.

DETAILED DESCRIPTION FIG. 1 is a perspective end view of the fender contemplated herein;

FIG. 2 is a view along lines 11-11 of FIG. 1;

FIG. 3 shows one type of tubular cross-section of the prior art;

FIG. 4 illustrates another type of tubular cross-section of the prior art;

FIG. 5 graphically shows the. characteristics of the tubular cross-sections shown in FIGS. 3 and 4;

FIG. 6 is a modification of the tubular cross-section shown in FIG. 4;

FIG. 7 is a further modification of the tubular crosssection shown in FIG. 4; and,

FIG. 8 again graphically shows the characteristics of the tubular cross-sections shown in FIG. 6 and FIG. 7.

FIGS. 1 and 2 illustrate a fender made in accordance with this invention. This fender represents a hollow cylinder with rectangular cross-section. This cylindrical body is made of an elastic material like rubber, and it consists of a buffer 1 which comes into contact with the ship side; a fixture 2 which contacts the quay wall and runs parallel to said buffer; and two supports 3 which are inserted between said buffer 1 and said fixture 2 and are flat on the outside surface, these two flat surfaces being parallelto each other. Said buffer 1 and said fixture 2 have embedded

reinforcing plates

4, 5.

Holes 6 bored on the surface of said buffer are intended for attachment of another buffer, while holes 7 bored on the surface of said fixture are intended for attachment of the fender to the quay wall, etc.

Interior surfaces of said supports 3 have their middle portion 3a flat and parallel to the exterior surface; the adjacent portions 3b of said middle portion 3a to the buffer and to the fixture are curved; and the junctions between said curved portions 3b and the buffer and fixture are depressed with a notch.

The fender according to this invention is designed as a rectangular tube for the purpose of enlarging the contact area with the ship and reducing the reaction per unit area. Its sectional profile is dictated by the pressure-receiving area and its internal shape is selected to make the reaction small and the displacement large. Tubular fenders with cross-sections, as illustrated in FIGS. 3 and 4, have been publicly known. One illustrated in FIG. 3 shows a characteristic curve, like 0- curve in FIG. 5, while one illustrated in FIG. 4 does a characteristic curve, like the P-curve of FIG. 5. In these fenders, however, the reaction rise is sharp and the energy absorption is extremely poor.

The fender of FIG. 4 has two supports parallel to each other and the present inventor tried ,to improve this fender. As shown in FIG. 6, leaving the flat portion 3a of the support as it is and providing a curved portion 3b between the buffer and the fixture, he obtained a characteristic curve, like the R- curve in FIG. 8. When,

I with the thickness of support kept constant, the radius of curved surface was increased and the fiat portion 3a was reduced, however, the displacement of support did not increase and the rise of the characteristic curve became steep. Conversely, when the radius was reduced and the flat portion 3a was enlarged, the reaction dropped, but the rise of the characteristic curve remained relatively steep.

By providing a notched depression 3c, as shown in Fig. 7, between the curved part and the buffer and fixture, only the displacement could be made as large as about 50 percent, as given by the S-curve in FIG. 8.

As testified by various experiments, the recommendable H(height) vs. W(width) relation is 2H i W R 1.25H. The desirable thickness (2) of the support, depending on the mutual relation between the radius (R) of curved surface, the length (E) of the fiat portion (3a) and the distance (M) of the notched depression from the outside surface of support, is t=(0.20 0.26)-H. The desirable range of E is E=(0.3 0.4)H, that of R being R=(0.22 0.30)H and that of M being M=.0.265-

A fender meeting these conditions has, as indicated in FIG. 8, a low reaction, a large displacement and a great absorption energy (A).

The fixture in this example represents a flat plate, but it may be separated by an open groove cutin the middle.

What is claimed is:

1. In a rectangular tubular fender to be fitted to quays for docking a large ship, made of elastic material and composed of a buffer (1), a fixture (2) and two supports (3) provided between said buffer and said fixture, the improvement therein wherein the exterior surfaces of said supports are made parallel to each other, the interior surfaces of said supports being flat and parallel to said exterior surfaces in the middle portion (3a) the adjacent parts (3b) of said middle portion to said buffer and said fixture being curved, and'the junctions (30) between said curved portion and said buffer or fixture being depressed with a notch, said fender meeting the following conditions:

Claims

1. In a rectangular tubular fender to be fitted to quays for docking a large ship, made of elastic material and composed of a buffer (1), a fixture (2) and two supports (3) provided between said buffer and said fixture, the improvement therein wherein the exterior surfaces of said supports are made parallel to each other, the interior surfaces of said supports being flat and parallel to said exterior surfaces in the middle portion (3a) , the adjacent parts (3b) of said middle portion to said buffer and said fixture being curved, and the junctions (3c) between said curved portion and said buffer or fixture being depressed with a notch, said fender meeting the following conditions: 2H > OR = W > OR = 1.25H, t (0.20-0.26)H, E (0.3-0.4)H, R (0.22-0.30)H, M 0.265.H + OR - 10%, where H is the height, W is the width, t is the thickness of the middle portion of the support, E is the length of flat portion of the support, R is the radius of the curved surface, and M is the distance of notched depression from the exterior surface of the support.