Note: Descriptions are shown in the official language in which they were submitted.
~B~
BACI<GRO~ND OF THE INVENTION
The present invention relates to a me-thod of
connecting a support rope and net meshes of a drift gill net
and a fixed net for fishing. A drift gill net is a type of
gill net which captures fish by taking advantage of drif-tage.
As is well known, a fishing net, for instance, a
fixed net, depends from the sea surface until it is expanded
in the sea as required. When counter boring moment, which is
a kind of pressure generated by waves on the surface of the
sea, or other forces are intensely exerted on the fishing
net, there is a possibility that the cords constituting the
support rope will be torn off and thereby the whole Eishing
net will fall to the bottom of the sea. Furthermore, there is
a necessity for making the connection of the fishing net to
the support rope having a large diameter a-t certain
predetermined intervals as seen in the longitudinal direction
of the support rope, when the fishing ne-t expansion operation
is performed.
With the foregoing background in mind, the
following requirements have been specified by many fishing
net users in many countries over the world:
1. There is a need for improvement in the assembly
and disassembly operations of a fishing net,
2. There is a need for a connection between the
support rope and -the fishing net without tying
the two together and at the same time avoiding
a tearing off of the fishing net from -the
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support rope,
3. There is a need for minimizing both the area
where -the net expansion operation is perEormed
and the time required for carrying out -the
expansion of the net.
In a typical conventional net expansion method, an
intermediate rope is connected to a main rope provided with
floats in the spaced relation, with the use of connecting
ropes interposed therebetween. A fishing net is then
connected to the intermediate rope by means of another
connecting rope having an elliptical or half-elliptical shape
as seen from the side, with a number of binding knots formed
along the upper edge of the fishing net. These connecting
ropes are called zig-zag ropes.
This structure of the conventional fishing net
using so-called zig-zag ropes leads to a resul-t that it
cannot be manufactured at an inexpensive cost. This problem
also applies to the case of a drift gill net which does not
require a main rope. Thus, the conventional drift gill ne-t
also cannot be manufactured inexpensively.
Accordingly, it is an object of -the present
invention to provide an improved method of connecting a
fishing net which is entirely free from the drawbacks
inherent in the conventional methods mentioned above.
SllMMARY OF THE INVENTION
The present invention relates to the method of
connecting a fishing net by successively connecting each net
mesh to the support rope and disassembling the -thus expanded
fishing net. The invention consists in -that a number of
loop-shaped ear portions are formed with the use of a single
cord which is in-tegrally stranded together wi-th the support
rope. A smaller ear portion is projected from the lower
surface of the support rope after the ear portion is
penetrated through the support rope. Successive connection is
carried out by inserting the ear portion through the circular
hollow space of the smaller ear portion, while each net mesh
is hung on the stre-tched ear portion. Fishing net expansion
is hence achieved without tying at any position along the
support rope. The fishing net thus expanded, can
satisfactorily stand against counter boring moment which is
generated by roaring waves on the sea.
With the foregoing and other objects, advantages
and features of the invention that will become hereinafter
apparent, the nature of the invention may be more clearly
understood by reference to the following detailed description
of the invention, to the appended claims, and to the several
views illustrated in the attached drawings.
BRIEF DESCRIPTION OE T~IE DRAWINGS
Figs. 1 and 2 are front elevations of a fishing net
made in accordance with the invention, illustrating how a
smaller cord S having a circular cross-sectional
configuration is stranded with the support rope in the
flexibly stranded state and a number of ear portions having
the same length depend from the support rope in an equally
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spaced rela-tion.
Fig. 3 is a fragmental view of the support rope
made in accordance with the invention, particularly
illustrating how a smaller ear portion E is formed during net
connecting operation.
Figs. 4 and S are further fragmental views of a
fishing net made in accordance with the invention,
illustrating how a main ear portion S is inserted through the
circular hollow space of the smaller ear portion E without
any formation of binding knot while net meshes are hung
thereon one by one.
Fig. 6 illustrates how the main ear portion S is
stretched in the transverse direction as seen from the side
one after another while net e~pansion operation is performed.
Fig. 7 is a fragmental enlarged view of the suppor-t
rope made in accordance with the invention, particularly
showing one of a number of projected parts which are formed
in the spaced relation on the lower surface oE the support
rope without any formation of binding knot.
Fig. 8 is a schematic view of the support rope
including the right-hand end par-t, particularly illustrating
how the ear portions are connected in accordance with the
method of the present invention.
Fig. 9 is a schematic view illustra-ting how an
unacceptable technical idea is constructed on principle, and
Fig. 10 is a fragme~tal view illustrating the
connecting method of a conventional fishing net.
As shown in Fig. 10, an intermedia-te rope R' is
connected to a main rope R provided wi-th floats in spaced
relation, with connecting ropes interposed therebetween. A
fishing net is then connected to -the intermediate rope R' by
means of another connecting rope R'' having an eliptical or
half-eliptical shape as seen from the side, with a number of
binding knots formed along the upper edge of the fishing net.
As noted above, these connecting ropes R'' are called zig-zag
ropes.
DETAILED DESCRIPTION OF A PREFERRED E~IBODIMENT
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Referring now in de-tail to the drawings, wherein
like parts are designated by like reference numerals and
letters throughout, there is illustrated in Figs. 1 to 3 a
support rope R which is constituted by the combination of a
plurality of unit cords (strands) and a single cord S having
the circular cross-sectional shape (the cord S having a high
tensile strength). Both types are stranded toge-ther in the
illustrated manner, wherein a number of ear por-tions S,S,S...
(which will be described in more detail later) depend from
the support rope R.
When the support rope R specially designed for
practicing the present invention is manufactured
automatically, each of the ear portions S,S,S... is uniformly
drawn downwardly from the rope in such a manner that the
depending length ~1 f the one ear S is a little longer or
substantially the same dimension as span Ll of said ear S as
measured between adjacent ear portions S.
In practical fishing operations using -the drif-t
gill net, a number of support ropes R of various diameters
(in the range of 3 to 50mm) were employed. However, for the
purpose of simplification, the description will be made below
Sonly to the case where the support rope R has a diame-ter of
7mm. In this case, the support rope R is a combination of
eight (8) unit cords stranded flexibly together with support
cord (designated "S" in the Figures of the drawings) out of
said eight (8) cords, having a diameter of 3mm (Fig. 2). The
10length ~ 1 of the ear por-tion S and span Ll between the
adjacent ear portion S are substantially the same and have a
length in the range of 25 to 30 cm.
To assure that functions to be described later are
achieved, the foremost end 1 of the ear portion S is inserted
15in the direction of expansion through the structure of the
support rope R and is then drawn downwardly therefrom until a
smaller hollow ear portion E is formed (Fig. 3). The smaller
ear portion E has a depending length ~2 as measured from the
position where the ear portion S comes out of the suppor-t
20rope R. Then, the next longer ear portion S is extended
through the smaller ear portion E in such a manner as shown
in Fig. 4 whereby advantageous features (which will be
described later) are obtainable. To assure that expansive
force and connecting force of the fishing net are
25substantially increased, and -that the disassembling operation
is easily performed without interruption, the smaller ear
portion E is formed in such a manner that dimensional
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3~3
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relation between 41 and L2 is established at the same ratio
of approxima-tely equal segments L2 as the foregoing
dimensional relation between ~1 and Ll. In the illustra-ted
embodiment, ~ 1 = L2 = 2.6cm is determined as a properly
S acceptable dimensional limit.
Since the support rope R specially designed for the
invention provides merely a number of depending ear portions
S,S,S... which have the same length ~1 as described above,
can be manufactured on the basis of mass production at
substantially the same cost as the conventional one despite
the kind of material used.
Next, the following description will illustrate the
step of connecting prior to net expansion operation wi-th
reference to Fig. 5. The foremost end 1 oE the first ear
portion S (not shown) is penetrated through the support rope
R with the aid of a suitable insert sleeve (not shown) while
it is held by operator's hand. Thereafter, said end 1 extends
in the direction of net expansion until it projects from the
support rope S (on the lower surface of the support rope) at
the position located in the proximity of the starting point
2' of span L2.
As will be apparent from the drawing, the projected
part of the ear portion S can be easily shaped to a smaller
ear portion E (Fig. 5). At this moment operator's visual
inspection or measuring operation will confirm whether the
dimensional relation ~ 1 = L2 is substantially established.
Then, the next ear portion S is extended -through
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the circular hollow space of the smaller ear portion E by its
full length (Fi~. 4). Thereafter, the connectin~ end part of
each of net meshes N is hung on the ear portion S one after
another before the latter is stretched in the -transverse
direction by a pulling opera-tion (Fig. 5)~
When the connecting opera-tion is completed by a
distance of about 25 cm (Ll) equal to one stretched section,
the next smaller ear portion E (as identified by point 3') is
formed in the same manner as mentioned above (Fig. 5). When
the smaller ear portion E has been so formed, -the following
ear portion S is extended through said portion E and this
operation is repeated in succession.
As a result of the present invention's method of
connecting the fishing net, the variable depending points 2',
15 3'of the smaller ear portions E,E,E(Fig. 5) are
located in the vicinity of the fixed depending points
1,2,3,4,5... of the loop-shaped main ear portions S,S,S...
(Fig. 6); and both the smaller ear portion E and the ear
portion S are overlapped one above another when the la-tter is
stretched in the transverse direction, whereby net expansive
force and durability of the support rope R are improved
multiplicatively.
In a number of fishing operations using a drift
gill net of which support rope had a diame-ter of 7 mm, and
which was not loaded with weights in the sea, it was
estimated that each of the support ropes (constituted by
eight (8) stranded unit cords made of polypropylene) for the
drift gill net had rope strength as well as expansive force
of 1,240 kg. It was assumed in this test that -the drift gill
net was immersed at the average depth of 10 m in the sea,
that its width in the expanded state amounted to 50 m and
that its to-tal weight as measured in the sea was 11.3 kg (it
should be noted that measurements were carried out in
accordance with relevant Japanese Industrial Standard
measuring methods).
When net expansion operation is performed on the
sea, according to the method of the present invention, a
series of convex shaped parts 6 without any binding kno-t
formed thereat are successively formed in the spaced relation
along the lower surface of the support rope R (Fig. 7) by way
of the steps of inserting each of the ear portions S
therethrough, upwardly displacing the combined s-tructure of
both ear portion and smaller ear portion and stretching -the
support rope R in the longitudinal direction. Owing to
formation of the convex parts 6,6,6... in tha-t way, -the
strength of the support rope R can be increased remarkably.
This leads to two advantageous features: (a) a
diameter of the support rope can be reduced at leas-t by an
extent of 1/5 to 1/4 compared with that of -the conventional
one, and ~b) manhours required for connecting operation of
the support rope to fishing net can be saved remarkably.
When the fishing net needs to be disassembled in
order to repair it or to replace it with another one, the
disassembling operation is initiated from the rearmost
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smaller ear portion E (Fig. 8) and it is completed by
disconnecting the ear portion from the smaller ear portion
and by repeating the same operations in the direction
opposite to that in the case of net expansion operation
whereby the whole fishing net N is disassembled from the
support rope.
Obviously, the connecting and disconnecting
operations will be performed in the same manner as described
above with respect to the bottom area of fishing net.
A11 practical Eishing operations in the above
description were performed in the fishing area on Japan Sea
and Pacific Ocean, and utilization of floats and weigh-ts (not
shown) was determined in accordance with conventional fishing
practices depending on the position where they were placed in
the sea (in the range of 2 to 1,000 m in depth).
In the case where fishing operation was performed
with the use of fixed net, fishing net expansion was achieved
by a width of 20 m at the position of 12 m in depth as
measured down from the sea surface. In this practical fishing
operation, the main rope R (Fig. 10) used therefor had a
diameter of 15 mm and it was found that the same fishing
effect was obtainable as in the case when the conventional
main rope having a diameter of 20 mm was used.
This means that a diameter of the main rope can be
reduced to an extent of 3/4 when compared with that of the
conventional one.
Further, in every embodiment mentioned above, it
303~
was confirmed -that time required for connecting and
disconnecting the same fishing net in width reduced by 1/20
compared with conventional ones, taking the difference swayed
by the place where the opera-tion was performed into account.
As long as the method of the present invention is
employed, the formation of the convex parts 6,6,6... without
any binding knot formed thereat and stretching pattern of
each of the ear portions S,S,S... in parallel wi-th -the
support rope (Fig. 8) can be visually recognized at all
times. Thus the support rope R exhibits a distinctly
characteristic appearance. In connection with the
advantageous e-Efects of the present invention, it should be
noted that in such a technical concept (as shown in Fig. 9),
adjacent loopshaped depending loops that are connected to one
another in the alternate manner without any consideration
taken for an occurrence of falling-down will belong to one of
lower concepts which will not be acceptable from the view
point of industrial utilization within the scope of the
patent law.
Although only preferred embodiments are
specifically illustrated and described herein, it will be
appreciated that many modifications and variations of the
present invention are possible in light of the above
teachings and within the purview of the appended claims
without departing from the spirit and intended scope of the
invention.
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