Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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Title: Coupling device for use in a mooring system for floating structures
Technical Field of the Invention
The invention relates to a coupling device for use in a mooring system for
floating
structures, subjected to pulling forces or tension arising in the mooring
system.
Background of the Invention
A typical floating aqueous fish farm plant consists of a number of cages
interconnected with neighboring cages and arranged in a predefined array of
floating
cages. The farm plant is moored to anchoring points on the seabed and/or shore
by
means of a number of mooring lines, extending from the farm plant to the
anchoring
points.
A cage system in a floating aqueous fish farm plant and/or other type of
floating
plants required to be moored to the seabed and/or shore require a mooring
system
comprising a large number of mooring lines pointing in horizontal and/or
vertical
direction and/or arranged in a sideways and/or downwards inclined or slanted
direction. Such systems are often configured in such way that nodes of mooring
lines
are required.
A typical cage comprises one or more floating collars, a net suspended from
the
collar(s), a mooring point for mooring the cage to one or more of the
neighboring
cages and/or to anchor points on the seabed/shore.
For quite some time the aquaculture fish farm industry has expressed a desire
to
reduce use of steel components in the upper part of the water known as the
splash
zone, which is the first 15 meters downwards from the surface. The splash zone
is
the area where corrosion is most extreme and where the effect of waves and
wind
are largest. Strict regulations require periodical inspection, such inspection
requiring
visual control. If tendency to severe corrosion, detrimental wear and tear, or
the like
is discovered, for example during such inspection, the affected component or
components must be replaced. Commonly such visual inspections are preformed
below sea level by divers or by remotely operated cameras. Replacement or
repair is
always performed by lifting the defect part out of the sea.
The purpose of the mooring system is to keep the floating structure in a fixed
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position, as well as to secure that the individual floating cages are retained
in a
spaced relation. The mooring system is dimensioned to secure the installation
and
consists of mooring lines in all four directions. Mooring lines are selected
to match
the type of environment they are to be used in, where weather, water current,
and
other properties of the surroundings are taken into consideration.
Previously, mooring systems consist of mooring lines attached to a large metal
collar
suspended with buoys in one end and to the anchors on the other end, said
elements representing a risk for collision or interference between collar and
nets
when subjected to waves and heavy sea.
Several of these coupling elements are used in a mooring system. The
introduction
of a coupling element adds balance to the mooring system, ensuring that the
float
collars are on a somewhat fixed distance from each other, yet still safely
secured.
Various alternatives to the steel ring are used in current mooring systems.
Most
widely used is a mooring plate, which is a round galvanized steel plate with
holes.
In a typical mooring system, every float collar is attached to a mooring plate
on all
four sides using a fiber rope in a type of crowfoot configuration where three
ropes
are connected to the float collar and the other end of these three ropes are
connected at the mooring plate. The mooring plates in the middle of the farm
will
thusly be surrounded with float collars and will have four collars attached to
every
plate. The mooring plates on the edges of the farm will have float collars on
one side
and will always have two collars attached to every plate. The mooring plates
on the
corners of the farm, will always only have one collar attached to it.
The mooring plates are also interconnected with straight fiber rope mooring
lines in
order to add the stability needed. These lines make up a square for every
float collar
in the system. The mooring plates on the edges as well as the mooring plates
on the
corners will also have mooring lines that stretch to the bottom of the water
body
where they are bolted, attached to an anchor, or fastened in another suitable
way.
These same plates are also attached to a buoy which holds the frame at a given
depth, normally between seven and ten meters below the sea level. This system
allows a build-up of a farm with as many float collars as needed, in any
direction.
Any line attached to any mooring plate will be fastened using several more
steel
components, such as shackles, thimbles, links and chains.
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Thimbles are used to increase the contact surface between the rope/mooring
line
and the coupling element and to protect the lines, in order to reduce strain
and gnaw
on the rope. This can be used in one end or in both ends of the mooring line,
whereupon the other end of the thimble usually is connected to a link or a
ring. In
prior art, there are known steel and plastic thimbles.
Traditionally, steel thimbles are used to form a closed loop or an eye. It is
also
known to use tube thimbles made of plastic material. Here the tube thimble is
given a
general U-shape with straight and parallel legs and a curved bottom region,
and
where the outer bottom surface of the U-shaped thimble is removed, enabling a
rope
or a wire more easily to be thread in through one of the legs at the bottom to
the top
and to be bent and threaded in through the other leg from the opposite end
from the
top to the bottom of the leg, following the U shape of the thimble, whereupon
the
rope or wire end is spliced to form a closed loop or thimble eye. When a rope
or wire
with such tube thimble of plastic material, fixed to a body, is tensioned, the
thimble
legs tend to be bent inward towards each other, whereby the legs of the
thimble and
the U-shaped bottom tend to be pressed towards each other, deformed to a more
or
less V-shape around the rig at the thimble bottom, thus forming an abrupt and
weakened point shaped transfer zone. A detrimental effect of this behavior is
that the
loop end of the rope or wire may be more pointed, reducing the thimble effect
and exposing the wire or rope to an increased wear and tear, thus creating a
possible weak link in the system rather than enhancing the mooring system.
A possible drawback with thimbles made of steel or plastic material is that
they are
not form stable if subjected to high tension in the lines. Contrary to
thimbles of plastic
material, which regain the original shape when the tension in the line is
relieved,
steel thimbles tend to retain the deformed shape. This may have a detrimental
effect
on the wire or rope reducing the protecting property of the thimble.
Prior art technology requires high maintenance costs and frequent quality
assurance,
as well as higher risk of component failure that may lead to escaping of fish.
Thus, it
is a need for an improved system for establishing multiple connections in a
mooring
system with several mooring lines interconnected and jointed in a mooring
node,
avoiding the drawbacks of the prior art solution.
Among publications relating to mooring one can mention: W02012154054 (Al) and
US 2100569 A.
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Objects of the present invention
At least some of the following object are intended to be solved by the
invention or by
embodiments of the invention.
A object of the invention is to provide components to be used in a mooring
system
that is reliable and requires less maintenance than existing components.
A object of the present invention is to provide connecting points or nodes
between a
structure and one or more lines,
Another object of the invention is to configure and design a thimble device
system
and choosing a thimble material having properties allowing the thimble device
system to regain its initial shape and configuration when the tension in the
line
ceases or is released.
Another object of the invention is to provide a thimble device allowing
connection to
a structure, where the thimble device allows for several lines or wires to be
connected substantially at one single contact point on the structure and also
configured to withstand large tension in the line(s) without any substantial
degree of
deformation.
An object of the present invention is to reduce or remove the disadvantages of
the
prior art solutions by eliminating or at least substantially remove the need
for using
metal parts or elements in the mooring system, thereby also eliminating
failure
caused by corrosion, and sharp edges associated with the mooring system in the
splash zone.
Yet another object of the present invention is to provide a coupling element
in a
mooring system that can withstand strain from forces in any and all
directions.
Another object of one embodiment of the present invention is to provide a
connecting
element that reinforces the connection between the thimble and the link, or
ring,
preventing deformation and damage of the tube thimble when exposed to strain
and/or tension.
There is also an objection of the present invention is to provide a connecting
element
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that reduces gnaw on the rope by allowing the inner surface of the thimble to
be
rotatably arranged on the outer single curved surface of the connecting
element.
There is an objective of the invention to provide a system where said thimbles
can
5 be made of a plastic material, such as polyurethane.
Another objective of the invention is to provide a method for fastening the
thimbles to
the coupling element where a thimble is threaded onto the coupling element
before a
mooring line or a rope is inserted and then spliced together to create a loop.
Further, an objective of the fastening method is that when the pull force
bending the
legs outward have been released the thimble will enfold around the coupling
element
and have a tight secured grip.
Yet one objective of an embodiment of the invention the object is to provide a
mooring system where the one or more tube thimbles are axially fixed in
sideways
manner on the coupling element in-between two or more locking bodies.
Another objective of the present invention is to provide a method where the
.. system can be used in a fish farm to keep floating installations in a more
or less fixed
position and where the connecting system can be connected to several different
elements such as anchors, buoys, floating collars etc.
Summary of the present Invention
.. In one aspect the invention relates to a coupling device for use in a
mooring system
for floating structures. The coupling device is subjected to pulling forces or
tension
arising in the mooring system. Said coupling device comprises a
circumferentially
coupling element, such as a ring, and where one or more U- shaped tube
thimbles
are threaded onto the coupling element and linked with mooring lines. The
coupling
element has locking bodies on each side and adjacent to one or more tube
thimbles
on the coupling element.
The curved inner surface of the U- shaped tube thimble can be provided with a
contact surface complementary to the contact surface of the coupling element.
At least one or more units of U-shaped tube thimbles can comprise two or more
U-
shaped tube thimbles, placed neighbouring and can be fixed together along the
U-
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shape end of the thimbles, and/or a bushing plate fixed to an inner surface of
the U-
shaped tube thimbles forming an integrated part of the thimble, facing towards
and
can be in contact with a corresponding surface on the coupling element when
fixed
on the coupling element and/or forming a single point of attachment in respect
of the
coupling element.
A width of the bushing plate can correspond to a width of the U-shaped tube
thimbles
at their closed bottom end and that a length of the bushing plates corresponds
to the
corresponding width of the assembled U-shaped tube thimbles.
The bushing plate can be curved both lengthwise and crosswise, both crosswise
and
lengthwise curvature being adapted to corresponding contact surface of the
coupling
element.
A pair of legs of one of the thimbles in the assembled U-shaped tube thimble
can
form an angle with the legs of the neighboring U-shaped tube thimbles, the
angle
being configured to match an ideal angle for a mooring line when assembled.
The coupling element can be in the form of a ring with a radius R and having a
circular cross section with a radius r, the crosswise and lengthwise curves of
the
bushing plate can be adapted to the correspondingly curved surfaces of the
ring.
The legs of a thimble can bend inward until the legs touch or almost touch
each
other, creating an eye in the thimble.
The thimble can be made from a plastic material, such as polyurethane.
The coupling element can have a steel core in the middle and can be covered by
a
plastic material, such as polyurethane.
The one or more U-shaped tube thimbles are rotatably arranged on the curved
outer
surface of a connecting element connected onto the coupling element.
The curved inner surface of the U-shaped tube thimble can be provided with a
contact surface complementary to the outer contact surface of the connecting
element and/or the inner surface of the connecting element can be provided
with a
contact surface complementaryto the contact surface of the coupling element.
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In another aspect the invention relates to a coupling device used in a mooring
system for floating structures, subjected to pulling forces or tension in any
and all
directions. Said coupling device comprises a coupling element constructed as a
circumferentially coupling element, with locking bodies arranged on said
coupling
element to fit a tube thimble in-between two locking bodies.
A tube thimble can be arranged in-between two locking bodies.
In another aspect the invention relates to a method for connecting the
coupling
device, by:
- bending the legs of the thimble outwards and inserting the coupling
element into
the center hole of the thimble, creating a tight grip when the legs are
released,
- inserting a mooring line in through one of the of the legs of the thimble
from the
bottom opening to the top, to be bent and threaded in through the top of the
other leg
from the opposite end and down to the bottom end of the leg, whereupon the
rope or
wire end is spliced to form a closed loop or thimble eye connecting the other
end of
the rope, wire or other flexible material to the desired position such as at a
buoy, net
cage and/or anchor, and
- wherein one or more of the tube thimbles are each arranged in-between two
locking bodies arranged on said coupling element.
The node system presented do not need as frequent maintenance and replacement
of part of the nodes and mooring system as existing systems. Moreover, the
system
is robust and not prone to corrosion. A further advantage is that the system
is stable
and allow a single contact point for a spread of lines in different
directions, still
avoiding collapse of the thimble when subjected to high tension.
A advantage of the system is that the thimble configuration due to the
properties of
the thimble material or combination of materials used; and the configuration,
dimensions and shape of the thimble units may withstand large tensional forces
in
the lines and regain its original shape and configuration once the tension in
the line's
ceases, thus avoiding more or less permanent deformation, all due to its
flexible
properties.
Yet another advantage is that the system reduces the risk for failure of the
node and
thus eliminated or at least substantially reduced risk for causing damage to
the cage
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itself.
The present invention relates in general to a system used for mooring tie-in
floating
and/or stationary structures together and a method for establishing such
systems.
More particularly, the invention relates to a coupling device for use in a
mooring tie-in
system for floating and/or stationary structures together, where the system
may be
subjected to pulling forces or tension in any and all directions. In one
embodiment
the system comprises a connecting element with double flanges on the sides and
a
transversally running slot configured to fit a link or a ring or onto the
coupling
element, and where a unit in the form of a U-shaped tube thimble is threaded
onto
the connecting element, further connected to a link in the slot and where the
thimble
is connected with a mooring line. The link, ring or the connecting element can
be
connected to a shackle, which in turn can be connected to a chain or a rope or
directly to a stationary or floating body, such as an anchor. The invention
also relates
to a method and use of such coupling element for mooring lines in a mooring
system
that may be subjected to pulling forces in any and all directions.
Brief Description of the Drawings
Embodiments of the present invention will now be described, by way of example
only, with reference to the following drawings wherein:
Figure 1 shows schematically an overview of an aquaculture fish farming plant,
comprising a number of interconnected cages, moored in a mooring system;
Figure 2 shows schematically a typical coupling element in the form of a ring-
shaped
node peripherally arranged at one side of the plant and with a configuration
of
connected mooring line, an anchor line and three interconnecting lines
provided with
different types of thimbles and closed end loops or eyes;
Figure 3 shows schematically one embodiment of a coupling element,
intended to be used in a node system according to the present invention;
Figure 4 shows schematically an embodiment with an integrated three tube
thimble
configuration according to the present invention, connected in parallel to
each other,
forming an integrated multi-thimble unit, all in according to the present
invention;
Figure 5 shows schematically a perspective of the coupling element with an
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assembled integrated multi-thimble unit configuration, consisting of three
tube
thimbles attached on the coupling element;
Figure 6 shows schematically and in perspective a U-shaped connecting element
with a slot according to an embodiment of the invention;
Figure 7 shows schematically and in perspective a front view of the U-shaped
connecting element with a slot according to an embodiment of the invention;
Figure 8 shows schematically and in perspective another embodiment of the U-
shaped connecting element with a slot;
Figure 9 shows schematically and in perspective, seen from the side the U-
shaped connecting element according to an embodiment of the invention;
Figure 10 shows schematically and in perspective a coupling system with a
coupling
element inside a tube thimble connected with a link;
Figure 11 shows schematically and in perspective a coupling device with
locking
bodies arranged; and
Figure 12 shows in a coupling device with locking bodies arranged adjacent to
tube
thimbles of different dimensions.
__________________________
Reference numbers on drawing
10 Aquafarming plant
11 Cages
12 Rows of cages
13 Interconnecting lines
14 Interconnecting lines
15 Nodes
16 Anchor lines
17 Anchors
18 Mooring lines for cages
20 Buoy
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21 Coupling element
22 Single thimble
25 Multi-thimble solution
26 Thimble in a multiple thimble
27 Tube
28 Legs
29 Bushing or plate
30 Connecting element
32 Flanges
34 Link
36 Coupling system
38 Slot
40 Groove
42 Taps
50 Locking body
a Small thimble space
b Large thimble space
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Detailed Description of the Invention
In the following, an embodiment of the invention shall be described in further
detail,
used in connection with mooring of an aquaculture cage assembly 10 in a marine
environment. The assembly or plant 10 shown in Figure 1 comprises six
cages 11, arranged in two interconnected rows 12, each of the two rows 12
containing three cages 11. The cages 11 are interconnected by an array of
connection lines 13, 14, forming a rectangular framework for mooring of the
cages
11. The interconnecting lines 13, 14 are interconnected at nodes 15, the nodes
15
also functioning as attachment points for mooring lines 18 for mooring the
cages 11
and as attachment points for anchor lines 16 extending between the nodes 15
and
anchors 17 on the seabed. According to the embodiment shown, the anchor lines
16
extend from the nodes 15 positioned along the outer periphery of the plant 10.
For
clarity, only one cage 11 is shown, while the position of the other cages is
indicated
by rings, the cages being of a type having a circular shape and may comprise
one or
more hollow floating rings (not shown), forming suspension for the net.
As further indicated in Figure 1, the cage 11 shown is connected to the four
nodes
15 by means of three mooring lines 18 at each point. The configuration of the
nodes
15 shall be described in further details below in connection with Figures 2
and 4.
As shown in Figure 1, every cage 11 is attached to a node 15 by means of
mooring
lines 18. The mooring lines 18 extend between nodes at each of the four
corners of
the framework formed by the interconnecting lines 13, 14, and the cage
11. The lines 18 may for example a fiber rope attachment of a crowfoot type
configuration where three ropes or lines 18 are connected to attachment points
(not
shown) on the float collar (not shown) from which the net of the cage 11 is
suspended and the other end of these three ropes are fixed at a corresponding
node
15. The nodes 15 in the middle of the farm plant, i.e. between the two rows of
cages
11 shown will thusly be surrounded with float collars and will have four
floating
collars attached to them in addition to the four interconnecting lines 13,14.
The nodes
15 along the peripheral sides of the farm 10 will have float collars on one
side and
will have two cages 11 attached to every node 15. The nodes 15 at the corners
of
the farm, will only have one float cage 11 attached to it together with two
interconnecting lines 13,14 and two anchor lines 16. The nodes 15 are also
interconnected with straight fiber rope interconnecting mooring lines 13, 14
in order
to add the stability needed. These lines 13, 14 make up a square for every
cage 11
in the system. The nodes 15 along the periphery as well as the nodes 15 at the
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corners will also have anchoring lines 16 extending to the seabed, fixed to an
anchor
17, or fastened in another suitable way. Each of the nodes 15 is also each
attached
to a buoy 20 (only one buoy is shown). The buoys like the rest of the mooring
system
are configured to have the necessary strength for the intended use and
purpose.
This system is flexible and may be assembled with many cages, expanding the
size
of the plant lengthwise and/or crosswise, achieved merely by adding numbers of
interconnecting lines 13,14, nodes 15, cages 11 and anchor lines 16 with
corresponding anchors 17.
One end of each of the interconnecting lines 13, 14, mooring lines 18 and
anchor
lines 16 are as shown in more detail, moveably attached together at the nodes
15.
Referring to Figure 2, one embodiment of a node 15 shall now be discussed in
further details.
According to the embodiment shown in Figure 2, two different looped groups of
line
ends are shown. One of the groups are single thimble loops or eyes 23, such
line
ends being the ends of either the interconnected lines 13, 14 and/or the
anchor
lines 16, while the other group comprises a plurality of interconnected
thimble loops
or eyes for connecting the cage 11 with the frame of interconnected lines
13,14 at
the joint between two interconnecting lines 13.14. A main embodiment of the
invention is this configuration where one or more single thimbles 22 are
arranged on
the coupling element 21 in the mooring system. The configuration of another
embodiment of the second group of thimbles shall be described below in
relation to
Figures 3 and 4.
Reference is made to Figures 3 and 4, where one embodiment of the thimble
group
according to the present invention will be described in more details. As
indicated
above, the present invention is configured to replace the prior art steel,
mooring
plates and steel thimbles, used in connection nodes 15 in a mooring system of
an
aquaculture farming plant 10, for example configured as shown in Figure 1.
According to one embodiment of the invention, such system comprises a coupling
element 21 shown here in the form of a closed ring-shaped structure, for
example
formed as a closed ring with circular or oval shape, ref. Figure 3. The
coupling
element 21 has a cross-sectional curvature r perpendicular to the curvature R.
The
purpose of the ring-shaped body 21 is to interconnect the various lines
13,14,16,18
in a secure way, thus serving as a connection point for one or more lines.
Figure 4
shows schematically a view of an embodiment of a multi-thimble solution 25
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according to the invention. According to the embodiment shown, the multi-
thimble
solution 25 comprises three separate U-shaped tube thimbles 26, arranged side
by
side and rigidly fixed together. The thimbles 25, 26 are preferably made of a
plastic
material, such as polyurethane, known to withstand the aggressive sea
conditions in
the splash zone. The system according to the present application has no sharp
edges that could cause damage to the net or to the fiber ropes. Due to this
construction, the interval for periodic inspections is much longer than for
the prior art
mooring plates and other products used in this part or mooring systems.
Each of the thimbles 25, 26 has a general U-shape and comprises a hollow tube
27,
where a part of the material of the tube 27 at the bottom of the U-shaped
thimble
25,26 is cut-off, providing access to the outer bottom surface of the U-shaped
tube
thimble 25, 26, making it easier to thread a rope or wire through the thimble
25,26 for
forming a loop or a closed eye at the end of the respective line.
According to one embodiment of the present invention two or more U-shaped
thimbles 26 may be arranged side by side, rigidly fixed together at the lower
region
of the U-shaped thimbles 25, 26, forming a one unitary, integrated body. This
may be
achieved as part of the moulding process of the multiple thimble unit 25, or
by
welding or gluing individual units together. According to the present
invention a
bushing 29 may be arranged across the inner curved bottom of the U-shaped tube
thimble/the multiple U-shaped tube thimbles 25. The purpose and configuration
of
the bushing 29 is to prevent the bottom part of the U-shaped tube thimble unit
25, 26
from becoming deformed when subjected to large tension on the associate
line(s).
The bushing 29 forms an integrated part of the thimble 25,26 and is\given a
shape
and configuration adapted to the shape and form of the inner curved part of
the
thimble(s) 25,26 on the one side and the form and shape of the coupling
element 21
on the opposite side. According to one embodiment the bushing 29 is formed in
the
moulding process of the thimble variant in question, thus forming an
integrated,
homogeneous part of the thimble 25, 26.
According to the multiple U-shaped tube thimble 25 shown in Figure 4, the
bushing
has a convex surface corresponding to the concave inner surface at the bottom
of
the multiple U-shaped tube thimble 25. The opposite surface of the bushing 29
has a
concave surface, the curvature being adapted to fit around the corresponding
inner
curvature of the coupling element 21. The thickness of the bushing is chosen
to give
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the sufficient rigidity of the thimble 25, 26. The convex surface of the
bushing 29 is
completely matched to the undulated concave surface of the multiple U-shaped
thimble 25, enhancing the rigidity of the thimble 25.
.. The length of the bushing 29 is longer than the total length along the
concave
surface of the multiple U-shaped tube thimble 26', extending outside of each
side of
the multiple U-shaped tube thimble 25. The bushing 29 is also curved in
lengthwise
direction to adapt to the corresponding curvature of a ring-shaped coupling
element
21.
According to another embodiment of the invention the coupling element 21 is
replaced by a connecting element 30, with reference to Figure 10. The purpose
of
the connecting element 30 is to serve as a reinforcement for a single
connection
point for either one of the various lines 13,14,16,18, through a single tube
thimble 22,
creating a single point of attachment. Alternatively connecting elements 30
can be
used in a multiple thimble solution in a double, triple 25, 26 or otherwise
multiple
thimble (not shown in the figures).
According to this embodiment, the thimble 22 is threaded onto a coupling
element
30, as shown in Figure 10. The U-shaped coupling element 30 is formed as
a body with a cross-sectional curvature r perpendicular to an axial notch 38,
and a
parallel cross-sectional curvature R, as seen in Figure 8.
The connecting element 30 has a single curved, convex outer surface
corresponding
to the concave inner surface at the center hole of the U-shaped tube thimble
22. The
inner surface of the tube thimble is rotatably on the single curved outer
surface of the
coupling element, when the thimble is threaded onto the coupling element.
Outer
flanges 32 of the connecting element 30 will lock the thimble 22 in a sideways
manner, as the flanges 32 lay adjacent to the outer surface of the thimble
while in
the position where the thimble is threaded onto the connecting element, as
seen in
Figure 10. In one embodiment the thimble can be locked in a sideways manner by
adding one or more notches and corresponding taps on each side of the inner
surface of the tube thimble and the outer surface of the connecting element in
the
direction of the rotary movement where the taps are locked in the notches,
(not
shown). This can be added to the device or replace the flanges.
The slot 38 in the U-shaped connecting element 30 is adapted to fit around the
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curvature of a link 34 or a ring. The dimension of the connecting element 30
is
chosen to give the sufficient rigidity of the thimble 22, 25, 26. The convex
surface of
the connecting element 30 is completely matched to the undulated concave
surface
of the U-shaped thimble 22, enhancing the rigidity of the thimble 22.
5
At the sides of the connecting element 30, flanges 32 are extending
perpendicular to
the slot 38, as shown in Figure 6, 8 and 9. The flanges lock the component
sideways
only, thus allowing rotation of the U-shaped tube thimble 22 around the
connecting
element 30. This will allow for dynamic movement of the connection together
with the
10 water current without any friction between the rope and the U-shaped
tube thimble,
preventing gnawing.
With reference to Figure 10, an embodiment is shown where a link 34 is coupled
in
the slot 38 of the connecting element 30 with a tube thimble 22 threaded onto,
slot
15 facing towards the legs 28 of the thimble. A rope or a wire would be
threaded into the
one of the bottom legs 28 of the thimble 22, to then be bent at the top and
threaded
into the opposite leg from the top to the bottom, following the U- shape of
the
thimble, and then being spliced in a loop or an eye, locking the connecting
element
and the link (not shown). This configuration creates two pairs of cooperative
sliding
surfaces complementary arranged. The convex outer surface of the connecting
element 30 operates with the inner concave surface of the tube thimble 22, and
the
inner surface of the connecting element operates with the outer surface of the
link. In
an alternative embodiment (not in the figures), a separate connecting element
30
could be placed inside each center hole of a multiple tube thimble
configuration as
shown in Figure 4, e.g. three separate connecting elements 30 in one triple
tube
thimble 25. In another alternative embodiment (not shown in the figures), one
large
variant of the connecting element 30 could be used for a multiple tube
thimble, such
as a double tube thimble or a triple tube thimble for instance, where the
length of the
connecting element 30 is configured to match the multiple tube thimble 25.
The slot in Figure 6, 7 and 8 is shown as a deep notch starting at the surface
of the
connecting element 30, but it could also be formed as a narrow notch. The slot
is
shown as U- shape, but it could also be flat or have other forms created to
match the
surface of a link 34 or a ring. In an embodiment of the invention the body of
the
connecting element 30 has a U-shaped form, with an outer cross-sectional
curvature
r perpendicular to an axial slot 38, and a parallel cross-sectional curvature
R.
The connecting element 30 is not restricted to have a U-shaped form. In one
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16
embodiment it can be shaped as a closed structure, where the slot is going
straight
through the element, placed in an arbitrary position.
The connecting element 30 may be used in a single, double, triple or other
multiple
versions of the thimble solution. The connecting element 30 can be used as a
separate unit fitted in each center hole of the thimble in a single, double,
triple or
other multiple versions of the thimble solution. Alternatively, one connecting
element
30 can be used as joint element for each center hole of a multiple tube
thimble, such
as a double or triple tube thimble.
According to an embodiment, the legs 28 of the U-shaped thimbles 25,26, 22 may
point slightly towards each other in a direction towards the free end of the
legs 28,
thus allowing the thimbles 25,26,22 to be snapped onto the closed ring shaped
coupling element 21 or onto the connecting element 30 prior to threading and
splicing the rope or wire, thus avoiding the thimbles 26 to drop
unintentionally off the
closed ring shape coupling element 21, ref. Figure 4.
As seen in Figure 10, an embodiment of a coupling system 36 is shown, where
the
legs of the thimble have grooves 40 on the inside, creating an easier
positioning
insertion of the connecting element 30 into the thimble center hole. This
coupling
system 36 also shows a version of the thimble where the entrance into the
center
hole has two taps 42, one on each side, to ensure a more secure grip of the
connecting element 30.
As further indicated in Figure 4, the multi-thimble solution 25 is provided
with a
reinforcement and stiffening plate with a shape complimentary to the curvature
of the
inner bottom of the U-shaped individual thimbles 26.
Although a U-shaped tube formed thimble solution with a downwards and outwards
open end is shown, it should be appreciated that a closed solution may be
used.
Moreover, dimensions and angles of the thimbles 22, 25, 26 and shape,
curvature
and dimensions of the bushing 29 and connecting element 30 will be adapted to
the
forces appearing at the site of use and of the type of plant to be moored.
It should also be appreciated that the coupling element 21 may be configured
to
be split for entering completed eyes or loops of a line onto the coupling
element 21
without having to mount the lines out in the field.
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17
It should also be noted that the construction, configuration or shape of or
material
used in the coupling element 21 or ring or in the connecting element 30 may be
stainless steel, a polymer coated steel ring or other suitable, corrosion
resisting
material. The connecting element 30 could also be made of a plastic material
such
as polyurethane.
According to another embodiment of the invention, locking bodies 50 are
arranged
on coupling element 21, spaced apart at a distance to fit a tube thimble 22,
25,26 in-
between two locking bodies 50. This is shown in figure 11. As seen in this
figure the
locking bodies 50 are spaced apart at different distances to fit tube thimbles
of
different sizes. As an illustration only, the space a shows a spacing for a
small tube
thimble 22 and the space b shows a spacing for a larger tube thimble 22. This
is a
way of example only and is not limited to the invention. Any such combination
is
possible according to the invention. On a coupling element 21 there may be
several
different spacing for several tube thimbles 22 of different sizes and
multiplicity such
as single thimble, double thimble, triple thimble and so on. When the tube
thimble 22
is arranged on the coupling element 21 adjacent to a locking body 50 on each
side,
the thimble 22 is locked in a sideways grip. Thus, the thimble is unable to
slide or
move along the ring. This is illustrated in figure 12. As seen in this figure
there are
several small and large tube thimbles 22, 25, 26 that are locked on the
coupling
element 21. The advantage with this embodiment is that when the coupling
element
21 is not in a horizontal position, the position of the one or more thimbles
22 will be
fixed on the coupling element 21. According to the invention the locking
bodies can
be used on one or more single thimbles, one or more double or multiple
thimbles or
on a combination thereof. The locking bodies 50 may also be used to defines a
limited area on the coupling element 21 for instance for dividing the coupling
element
21 in four quadrants where the one or more thimbles can move freely within the
defined space.
