Fender

Details Fender Fender

1998-07-23

2001-02-13

Thibodeau, Paul (Department: 1773)

Stock material or miscellaneous articles

Structurally defined web or sheet

Including components having same physical characteristic in...

C428S031000, C428S517000, C428S519000, C428S495000, C114S219000, C114S220000

Reexamination Certificate

active

06187420

ABSTRACT:

BACKGROUND OF THE INVENTION
The present invention relates to a fender serving as a shock absorber at the time when a ship comes alongside or moored at the pier.
A fender as a shock absorber is disposed at the pier to protect both the ship and pier from an impact or friction produced at the time when the ship comes alongside or moored at the pier of the harbor.
As shown in FIG.
4
(
a
), a fender
40
comprises a top section
40
as a contact surface with a ship body, and a leg section
44
attached to both ends of the top section
42
, and is fixed to a pier
50
by inserting a bolt
48
into a flange section
46
of the tips of the leg section
44
. As shown in
4
(
b
), this fender
40
protects the ship body by deforming the leg section
44
to reduce the impact at the time when the ship comes alongside the pier.
As the fender, a fender made of rubber has widely been used, heretofore. However, since a rubber material used in the fender has normally a large friction coefficient &mgr; of not less than 1, when a ship body
52
comes into contact with the fender
40
diagonally (at the time when the ship comes in contact with the pier diagonally), an excess force is locally exerted and deformation of the fender
40
becomes non-uniform. As a result, not only is the desired shock absorbing performance not exerted, but also the fender
40
itself is liable to cause damage such as crack and the like.
Since the ship body always rolls by an influence of wave and wind while the ship is moored at the pier, a friction force is produced between the fender and ship body. Therefore, as shown in
FIG. 6
, a shear force is exerted on the fender
40
by friction with the ship body
52
and the fender is liable to be deteriorated, for example, damage such as crack and the like arise.
On the other hand, a fender obtained by forming a coating layer of a material such as polyurethane having a low friction coefficient &mgr; on the surface of a fender body of rubber alone is known, but the adhesion between the coating layer and fender body is low and the coating layer is liable to be peeled off.
To solve the above problems, there has been suggested a method of dispersing a compressive force given at the time when the ship comes alongside at the pier or reducing a friction force given at the time when the ship is moored at the pier by providing a surface layer
54
of a resin having a small friction coefficient, such as ultra-high molecular weight polyethylene (friction coefficient &mgr;=0.2) on the top section of the fender
56
to make the surface of the fender slippery, as shown in FIG.
7
. According to this method, the surface layer
54
is fixed by inserting a bolt
48
into a metal plate
58
embedded in the fender
56
.
However, since the friction coefficient of the surface layer
54
is low, a friction force between the bolt
48
or washer
49
and the surface layer
54
is small. When the above-described excess force or shear force is exerted at the time when the ship comes alongside or is moored at the pier, the surface layer
54
is removed from the bolt
48
section, as shown in FIG.
8
.
According to the above method, since parts such as is surface layer
54
, is metal plate
58
and a bolt are required, additionally, the production cost of the fender becomes higher. On the other hand, even if the surface layer
54
is directly bonded on the surface of the top section of the fender
56
without using the bolt, the bonding force between the surface layer
54
and rubber is low and the fender is considerably deteriorated.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a novel fender, which has a sufficient shock absorbing action with respect to a ship and is capable of dispersing a compressive force given at the time when the ship comes alongside at the pier and reducing a friction force given at the time when the ship is moored at the pier.
The present inventors have intensively studied to solve the above problems. As a result, the present inventors have found a new fact that, there can be obtained a novel fender, which has a sufficient shock absorbing action with respect to the ship and is capable of dispersing a compressive force given at the time when the ship comes alongside at the pier and reducing a friction force given at the time when the ship is moored at the pier. The fender includes a fender body made of rubber, and a surface layer with which at least an impact receiving surface of said fender body is coated, wherein said surface layer is made of a blended polymer of a crystalline polyolefin resin and a diene rubber and the proportion of the crystalline polyolefin resin in the blended polymer exceeds 50% by weight and not more than 85% by weight.
That is, the present invention provides:
(1) A fender comprising a fender body made of rubber, and a surface layer with which at least an impact receiving surface of said fender body is coated, wherein said surface layer is made of a blended polymer of a crystalline polyolefin resin and a diene rubber and the proportion of the crystalline polyolefin resin in the blended polymer exceeds 50% by weight and not more than 85% by weight;
(2) The fender according to the above item (1), wherein the blended polymer is dynamically cured;
(3) The fender according to the above item (1) or (2), wherein the fender body and surface layer are integrally bonded by cure of the fender body;
(4) The fender according to the above item (1), wherein a friction coefficient of the crystalline polyolefin resin is from 0.2 to 0.3; and
(5) The fender according to the above item (1), wherein the proportion of an ethylenically unsaturated bond in the diene rubber is not less than 1.2% by weight.
According to the fender of the present invention, by using a conventional fender made of rubber having an excellent shock absorbing action as a fender body and coating an impact receiving surface of the fender with the above surface layer, a friction coefficient of the surface of the fender can be reduced. As a result, a sufficient shock absorbing action can be exerted and, at the same time, a compressive force given at the time when the ship comes alongside at the pier can be dispersed and a friction force given at the time when the ship is moored at the pier can be reduced.


REFERENCES:
patent: 4735982 (1988-04-01), Orndorff, Jr.
patent: 4756266 (1988-07-01), Sakuraoka
patent: 4854258 (1989-08-01), Hausmann et al.
patent: 5095840 (1992-03-01), Kramer
patent: 5362572 (1994-11-01), Hamada et al.
patent: 5702827 (1997-12-01), Itoth et al.
patent: 5791278 (1998-08-01), Orndorff, Jr.
patent: 5977259 (1999-11-01), Sugimoto et al.
patent: 6012760 (2000-01-01), Nozika
patent: 0405954A1 (1991-01-01), None
patent: 9722759 (1997-06-01), None
patent: 9722758 (1997-06-01), None

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