Abstrict An apparatus for harvesting crayfish and similar crustaceans from
ponds utilizing a hollow tube placed in the pond and provided with
openings sized to allow crayfish to enter the hollow tube where
they are pushed through the tube by the action of a plug being moved
through the tube.
Claims What I claim is:
1. An apparatus for harvesting crayfish or similar crustaceans
from a body of water which comprises:
(a) a hollow tube positioned adjacent to the bottom of said body
of water, said tube having a series of openings in its exterior
wall surface connecting to the hollow passageway of said tube, said
openings having a shape and positioned to permit crayfish to pass
through said openings and into said passageway,
(b) a plug means positioned in said passageway, said plug means
having an outer perimeter area shaped to be adjacent to the inner
wall surface of said tube, and
(c) a second means attached to said plug means to move said plug
means through said passageway.
2. An apparatus according to claim 1 wherein a flap is attached
at one end to the outer wall surface of said tube and positioned
across each of said openings with its opposite end positioned beneath
the inner wall surface of said tube and constructed of resilient
material having sufficient flexibility to be pushed into said passageway
by said crayfish.
3. An apparatus according to claim 2 wherein one end of said flap
is constructed from polyethylene having a thickness of about 0.035
inches.
4. An apparatus according to claim 2 wherein said flap is triangular
in shape and positioned with one of its apex ends extending beneath
said inner wall surface.
5. An apparatus according to claim 1 wherein said passageway is
circular in cross-section.
6. An apparatus according to claim 5 wherein said plug means comprises
a ball.
7. An apparatus according to claim 5 wherein said plug means comprises
a disc having a perimeter area constructed of flexible material
that extends toward said inner wall surface of said tube.
8. An apparatus according to claim 5 wherein said plug means comprises
parallel separated disks attached to one another, each of said disks
having a perimeter area constructed of flexible material that extend
toward said inner wall surface of said tube.
9. An apparatus according to claim 1 wherein said second means
comprises a line attached at one end to said plug means and extending
through said passageway and operatively attached at its other end
to a first cranking assembly.
10. An apparatus according to claim 9 wherein said second means
further comprises a second line attached at one end to said plug
means and extending through said passageway in a direction opposite
said first line and operatively attached at its other end to a second
cranking assembly.
11. An apparatus according to claim 1 wherein said second means
comprises a line attached at one end to said plug means and extending
through said passageway where it is looped around a first pulley
assembly and extends back through said passageway to loop around
a second pulley assembly positioned at the opposite end of said
tube than said first pulley assembly and then extending back into
said passageway where said line's opposite end is attached to said
plug means, and a third means operatively attached to said line
to move it through said passageway.
Description BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to crayfish and similar crustaceans, and
more particularly to apparatus for harvesting crayfish from ponds.
2. Prior Art
Crayfish have long been considered a delicacy in the Scandinavian
countries, France and in parts of the United States. The traditional
method of harvesting crayfish was through the use of underwater
wire mesh traps set out in bodies of shallow water which crayfish
naturally inhabited.
With the increased popularity of crayfish as an edible food the
supply of crayfish from natural habitats was neither stable enough
nor plentiful enough. This led to the development of artificial
ponds used to raise crayfish, and the need to develop methods and
apparatus for easily, quickly and cheaply harvesting the crayfish
from these ponds.
Examples of some of the newer methods and devices to harvest crayfish
are disclosed in the following U.S. Pat. Nos. 4449479 issued on
May 22 1984 to Howard J. Saucier and entitled "Crayfish Harvesting,
Sheltering and Spacing Apparatus"; 4554759 issued on Nov.
26 1985 to Robert J. Edling et al and entitled "Method and
Means for Harvesting Crayfish"; and 4563830 issued on Jan.
14 1986 to C. Dean Cain et al and entitled "Process &
Apparatus for Harvesting Soft Shell Crayfish".
Despite the extensive research that has been conducted both in
the United States and abroad there still remains the problem of
finding a less labor intensive method and apparatus for harvesting
of crayfish, particularly crayfish raised in man-made ponds.
SUMMARY OF THE INVENTION
Therefore it is an object of this invention to provide apparatus
which can be used to harvest crayfish from both natural bodies of
water and man-made ponds.
Another object of this invention is to provide apparatus which
can efficiently harvest crayfish with the least amount of physical
damage to the crayfish.
Still another object of this invention is to provide apparatus
for harvesting crayfish which is not labor intensive.
Still a further object of this invention is to provide apparatus
for harvesting crayfish that is simple in construction and operation.
Other objects and advantages of the invention will be apparent
from the ensuing descriptions of the invention.
Accordingly, an apparatus for harvesting crayfish is provided comprising
an elongated hollow tube having a series of opening in its exterior
surface opening into the tube's passageway, each opening being sized
to allow crayfish to enter the passageway from the outside of the
tube, a plug means located inside the passageway and being sized
so that as it is moved through the passageway by a second means
it forces the crayfish through the passageway and out through one
end of the tube where the crayfish are dumped into a container.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a top view of a preferred embodiment of the invention
shown in a typical crayfish pond configuration.
FIG. 2 is a side view taken along lines A-A of FIG. 1 of one preferred
embodiment of the invention in the crayfish pond.
FIG. 3 is a side view of an alternate preferred embodiment of the
invention in a crayfish pond illustrated in FIG. 2.
FIG. 4 is a cross-sectional view of a ball-shaped plug device that
can be used as part of the invention.
FIG. 5 is a cross-sectional view of a parallel disc-shaped plug
device that can be used as part of the invention.
FIG. 6 is a cross-sectional view of an alternate preferred disc-shaped
plug device that can be used as part of the invention and illustrating
an automatic crayfish food supply line.
FIG. 7 is a top view of a preferred embodiment of the flap that
can be used as part of the invention attached to the hollow tube.
FIG. 8 is a cross-sectional view of a preferred parallel disc-shaped
plug device that can be used as part of the invention.
PREFERRED EMBODIMENTS OF THE INVENTION
Referring now to FIG. 1 a typical man-made crayfish pond 1 is shown
wherein a series of the crayfish harvesting assemblies, denoted
generally by the numeral 2 have been positioned in pond 1.
A typical pond will be 50 to 250 acres in size and generally rectangular
in shape. The hollow tubes 3 which form part of assemblies 2 can
be positioned in any manner in pond 1 but it is preferred that
they be positioned parallel to one another as the configuration
most efficient in harvesting the crayfish. Although there is no
theoretical limitation as to the length of tubes 3 it is preferred
that the length be less than 300 feet to facilitate pulling a plug
means through the passageway of tube 2 at a reasonable rate without
damage to the crayfish.
FIGS. 2 and 3 disclose alternate preferred embodiments of the tube
configuration and mechanisms for pulling the plug means through
the tube 3. In these embodiments tube 3 is positioned on the bottom
4 of pond 1 whereby a series of openings 5 lie above bottom 4 in
position to allow crayfish that are on the bottom 4 to easily enter
the openings 5. At least one end of tube 3 extends above water surface
6 and over pond bank 7.
In FIG. 2 both ends 8 and 9 of tube 3 extend above surface 6 and
over pond bank 7. At end 8 a pulley assembly 10 is positioned to
receive line 11 extending through tube 3. At end 9 a cranking assembly
12 is positioned to receive the other end of line 11. Thus line
11 is operatively connected to pulley assembly 10 and cranking assembly
12 to allow it to be moved back and forth in tube 3. In FIG. 3 pulley
assembly 10 is attached directly to tube end section 13 beneath
surface 6 as shown. In both embodiments a basket 14 is placed beneath
tube end section 15 to catch crayfish as they are forced through
tube 3 as explained below.
Alternate preferred embodiments of the plug means 16 used to force
crayfish through the tube passageway 17 are illustrated in FIGS.
4 through 6. In FIG. 4 the plug means 16 comprises a plastic or
rubber ball to which line 11 is attached to eyelets 18 and 19 that
have been screwed into or otherwise fixedly attached at opposite
points on ball 16. More particularly one end of line 11 is attached
to eyelet 18 and the other end is extended around the pulley of
pulley assembly 10 such as seen in FIG. 3 and looped back through
passageway 17 where it passes over the top of the ball and operatively
about cranking assembly 12 before passing back into passageway 17
where it is attached to eyelet 19.
In a more preferred embodiment plug means 16 will be constructed
utilizing parallel discs (FIG. 5) or a single disc (FIG. 6) in order
to minimize the damage to the crayfish as they are forced through
passageway 17 as explained below. In the FIG. 5 embodiment two rigid
plates 20 and 21 are attached to one another in parallel configuration
by threaded rod 22 which screws into threaded plate openings 23
and 24 as shown. Attached respectively to each plate 20 and 21 is
a rubber or similarly flexible disc 25 and 26. Discs 25 and 26 are
sized so that their perimeter edges are adjacent or in contact with
inner tube surface 27. In a preferred embodiment both the passageway
and the discs are circular in shape.
Alternately as shown in FIG. 6 there can be a single disc 28 of
dual durometer construction whereby the inner section 29 is of a
rigid composition and the outer perimeter section 30 is of flexible
composition. This allows eyelets 18 and 19 to be attached to the
rigid inner section 29.
In another preferred embodiment bait is automatically feed into
passageway 17 to attract the crayfish by introducing the bait into
one end of hollow tube 31 which runs parallel to tube 3 and is connected
by hollow tubular sections 32 that allow the bait to flow through
passageways 33 and 34 and into passageway 17. In a more prefered
embodiment there will be a connecting tubular section 32 located
near each opening 5.
As shown in FIG. 7 it is preferred that a flap 35 be attached by
staples or by screw 36 to the outer surface 37 of tube 3 in a position
to extend over opening 5. More preferably flap 35 will be triangular
in shape and of sufficient length so that the tip end 38 can extend
into passageway 17 and beneath inner tube surface 27. In a still
more preferred embodiment flap 35 will be constructed from semi-rigid
material such as polyethylene, preferably having a thickness of
about 0.035 inches, that will flex inward when a crayfish attempts
to enter passageway 17 through opening 5 but will block opening
5 so that the crayfish are not forced through opening 5 when plug
means 16 is moved through passageway 17 as discussed below.
A more preferred embodiment of plug means 16 is illustrated in
FIG. 8. In that embodiment the plug means 16 comprises a rear disc
assembly 39 and a forward disc assembly 40 positioned parallel to
one another by an elongated threaded bolt 41 or similar means.
The rear disc assembly comprises parallel rigid discs 42 and 43
which sandwich a flexible disc 44. These three discs are held in
position by passing threaded bolt 41 through center openings in
each disc and then by tightening nut 45 against washer 46 the three
discs are squeezed together by the tightening of washer 47 and washer
46 against the outer surfaces 48 and 49 of discs 42 and 43 respectively.
In this embodiment flexible disc 44 is of sufficient diameter to
contact inner tube surface 27 and more preferably is constructed
from polyethylene or similar material having a thickness of about
0.035 inches.
The front disc assembly 40 like rear disc assembly 39 comprises
parallel rigid discs 50 and 51 which sandwich flexible disc 52.
The front disc assembly 40 differs in that a second flexible disc
53 is fixedly attached to the front surface 54 of rigid disc 51
by staples 55 or similar means. These four discs are held in position
separate but parallel to the three rear disc assembly discs 42
43 and 44 by tightening nut 56 against washer 57 whose horizontal
movement is restricted by nut 58 and washer 59 positioned against
disc 50. In this embodiment both flexible discs 52 and 53 contact
inner tube surface 27 and are also preferably constructed of polyethylene
or similar material having a thickness of 0.035 inches.
In operation tubes 3 will be positioned on the bottom 4 of pond
1 and bait will be placed in passageway 17 adjacent openings 5 in
order to attract crayfish. As the crayfish enter passageway 17 through
openings 5 they push flap 35 down to create sufficient room for
them to enter. The crayfish enter passageway 17 and move toward
the bait. At predetermined time intervals cranking assembly 12 is
activated causing line 11 to be drawn toward cranking assembly 12.
This causes plug means 16 to move down passageway 17. This action
forces the water inside of passageway 17 to also move toward cranking
assembly 12. A portion of this water will exit openings 5 so as
to require less force to move the plug means 16 down passageway
17. Thus, the combination of moving water and moving plug means
16 forces the crayfish to move toward cranking assembly 12. It has
been found that as a result of the moving water that little or no
damage occurs to the crayfish during this cranking process. This
is particularly true when utilizing the disc shaped plug means shown
in FIG. 8. The plug means 16 is cranked to the position necessary
to force the crayfish inside passageway 17 to exit tube end section
15 and fall into basket 14. The plug means 16 is then cranked in
the opposite direction until it is repositioned near tube end section
13. This process is then repeated as often as desired.
From the disclosures above there are of course many alternate embodiments
which are obvious and are intended to be included in the scope of
this invention as defined in the following claims. |