Improvements in or connected with Trawl-nets for Fishing.
Year: 1895

page_text: Improvements in or connected with Trawl-nets for Fishing.
1, JOHANN COHRS of 26 Grosse Elbstrasse, Altona, in the Empire of Germany,
Fish Auctioneer, do hereby declare the nature of this invention, and in what
manuer the same is to be performed, to be particularly described and ascertained
in and by the following statement :-
This invention relates to improvements in or connected with trawl-nets for
fishing whereby the mouth of the net is kept open without a beam by means of
wheels running obliquely on the ground at the bottom of the sea, with the
expenditure of very little power.
"
In the accompanying drawings
. L
21
Figure 1'is a plan of a trawl-net with my invention applied thereto. Figure 2 is
a side elevation.of same.
Figure 3 is a sectional elevation, to a somewhat larger scale, of one of the
abovementioned wheels showing the connection to the front end of the net, and
Figure 4 is a plan of one pair of such wheels as connected to one side of
the net.
"
In ground trawl-nets without beams as heretofore used the mouth of the net has
been kept open by oblique boards (called "otter-boards") standing vertically in
the water, which tend to separate from one another as the net is drawn forwards,
thereby holding the mouth of the net open. The inclined position of the ""otter
boards causes them to offer considerable resistance to motion through the water and
they therefore require a correspondingly large expenditure of power to draw them
forward; they also possess the disadvantage that on uneven ground they are liable
to dig in and so bring the net to a stand, causing breakage of the towing ropes
and frequently loss of the entire gear.
The object of my ipvention is to obviate these disadvantages.
My apparatus consists of two pairs or sets of wheels A, each pair adapted to
rotate on an axis a, and made of iron or other suitable heavy material. These pairs
or sets of wheels are attached to the sides at the front end of the net as shown
in the drawings, and they run on the ground holding the net down in the proper
position. Each pair or set of wheels is constructed as follows:-On the axle a
are mounted, so as to be free to rotate thereon, two, or any other suitable number
of wheels b. A frame c is fixed to the axle a, between the wheels, in such
manner that the said axle divides it into two triangles the inner sides d of
which are shorter than the outer ones c so that the connecting point e of the towing
rope D and the connecting point of the front end of the side B of the net swerve
inwards from the centre line between the wheels, at an angle of about 20 to
30 degrees, whereby the two pairs of wheels are caused to assume an oblique
position with regard to each other and with regard to the centre line of the net.
The fastening of the net to the rear angle of the frame is effected by con-
necting in any suitable way the ground line É direct to the point f, and the head
line F to an iron bar g fixed to the frame at f, whereby an adjustment of the net
opening can be effected in a vertical direction. On the axle a is secured an oar-
like piece which serves to hold the wheels in equilibrium while they are sinking
in the water.
The action of the apparatus is as follows :—
When the net is thrown out the heavy wheels act as weights to draw the net

page_text: When the towing ropes³ D are pulled the wheels roll on the ground and draw the
net after them, both pairs of wheels having a tendency to run off in an oblique
direction, in consequence of the peculiar position of the points of attachment of the
towing ropes.and net to the frame cd, and the net is thereby drawn out to its full
width. The oblique action necessary for keeping the mouth of the net open is
thus produced by wheels rolling on the ground instead of by lateral surface
pressure as in the "otter boards" heretofore in use, the most important con-
sequences of which are that the net can be drawn forward with greater speed
and can pass over irregularities of the ground much easier than with the
arrangements at present in uso.
Having now particularly described' and ascertained the nature of the said inven-
tion, and in what manner the same is to be performed, I declare that what I.
claim is :-
-
3.
First. The improvement in or connected with trawl-nets which consists in the
employment of two sets of wheels A the axles a of which carry frames d whioli
are so formed that the connecting points c for the towing ropes, and for the net
are placed inside the center lines of the sets of wheels for the purpose of imparting
to the latter a tendency to diverge as they roll on the ground, substantially.as
described.
Second. In connexion with the improvement forming the subject of the first
claiming clause hereof, the use of a bar o connected to the frame e difixed to the
axles of the wheels, for securing the head line of the net so that it can be adjusted
vertically, substantially as described.
Third. In connexion, with the sets of wheels forming the subject of the first
claiming clause hereof the use of an oar like piece h for the purpose of preventing
the wheels from tilting over while sinking in the water, substantially as
described. .5.
ليمي
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