AU610828B2

AU610828B2 - Collapsible crab trap

Info

Publication number: AU610828B2
Application number: AU74590/87A
Authority: AU
Inventors: Desmond Peter Birks
Original assignee: Individual
Current assignee: Individual
Priority date: 1986-06-18
Filing date: 1987-06-18
Publication date: 1991-05-30
Anticipated expiration: 2007-06-18
Also published as: AU7459087A

Description

'I

610U828 COMMONWEALTH OF AUSTRALIA Patents Act 1952 0040 0 0041 0444 0 4 00 o 44 00 000 0 0404 0044 0 004 00 00 0 444 0 41 00 4 004~ 0 0 0044 40044 0 44 040 4 :3r-O1Z*- 1DRE' EF" 13TIR3ES PROVISIONAL SPECIFICATION FOR THE INVENTION ENTITLED:- "COLLAPSIBLE CRAB TRAP" This invention is described in the following statement:- Commwonwealth of Australia.

2 This invention relates to traps for crabs, fish and other crustaceans.

This invention has particular application to crab traps and reference hereinafter will be made to such application. Various types of traps are used to catch crabs.

A common form of trap known as a "crab pot" generally comprises a mesh frame provided with tapered mesh inlet passages which extend inwardly to the interior of the pot so that the passage is inaccessible to crabs once inside the pot. In use, a bait is set within the pot to attract crabs and doors are provided to enable the trapped crabs to be manually removed. These types of traps are very effective in use, however they can be difficult to use, they are cumbersome and thus they are not suited for stowage on pleasure boats and the like.

Another form of trap which is frequently used is a o«0 "dilly net". A dilly net simply comprises a hoop like frame within which a net is secured. In use the dilly net is left on the bottom with a bait centrally thereof and the net is raised to the surface at regular intervals to carry any crabs thereon to the surface. These traps have the disadvantage that they must be frequently tended and thus they are not popular in use.

A further type of trap which is called a "suicide net" or an "upside down dilly" comprises a light net connected to a supporting hoop and extending upwardly to an I apex which is supported by a float. The bait is supported within the cone formed by the net. When crabs swim towards the bait they become entangled in the net. While such traps are very effective in use they have to be checked at regular intervals to ensure that the trapped crabs do not free themselves by destroying the net. Furthermore, ELs the net in such traps has to be made from lightweight material in order to entangle the crabs it is easily damaged in use and freeing 3 crabs from the net may be difficult.

The present invention aims to overcome the abovementioned disadvantages and to provide a trap which will be reliable and efficient in use. Other objects and advantages of this invention will hereinafter become apparent.

With the foregoing and other objects in view, this invention in one aspect resides broadly in a trap for trapping crabs including:a base wall assembly; a collapsible enclosure assembly supported by said base ooo wall assembly, said enclosure assembly including a net enclosure and net supporting means supported by said base wall assembly for movement between a folded position at which said net supporting means lies juxtapositioned said base wall assembly and a supporting position at which said net "0 supporting means provides support for extending said net c enclosure upwardly from said base wall assembly to form said enclosure assembly; a trap inlet opening in a side wall of said net enclosure, and 0 o. a closable trap outlet in said base wall assembly which Smay be released for discharging trapped crabs.

°o The base wall assembly may be a rigid mesh wall provided with a door therein through which trapped crabs may be removed but preferably includes a net wall assembly including:a perimeter frame; an open ended tubular net having one open end fixed to the perimeter frame and the other open end constituting said closable trap outlet, and a drawstring associated with said other open end whereby said closable trap outlet may be drawn by said drawstring to

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I -T 0'f 4 a closed attitude and which drawstring may be released to open said closable trap outlet to allow trapped crabs to spill from the trap. The net enclosure may be in the form of a sleeve or tube like and the net supporting means may be a strut. In such arrangement the strut may be provided with net holding means associated with the open end of the net remote from the base wall and adapted to hold the net about the supporting strut.

The net holding means may be in the form of a drawstring about the open end of the enclosure net.

Alternatively the net holding means may be a hook secured to the strut and selectively engageable with the net to hold it in the operative position. Alternatively the hook may be fixed to the net and adapted to be releasably secured to the strut or to the perimeter frame of the net wall assembly.

The strut may be disengagable from the perimeter os frame, however preferably the strut pivots from a folded 0 position at which the strut extends across the base well assembly, and a supporting position at which the strut extends upwardly from the base wall assembly.

The perimeter frame may be circular or square or in any other configuration as desired. Preferably the tubular net forms both the base wall portion of the base wall o assembly and the net enclosure and drawstrings are provided to close both ends of the net at opposite sides of a perimeter frame.

In such arrangement the lower end of the supporting strut may be attached to a tension member stretched between opposite side portions of the perimeter frame. If desired the enclosure net may be provided with one or more stiffening arch frames or the like adapted to be raised with the enclosure net above the base wall when the net is stretched to its enclosing attitnide. Such arch frame may constitute Io r- said supporting member. Preferably, the side wall formed by the enclosure net extends inwardly and upwardly from the retaining perimeter frame so that trapped crabs which move along the base wall of the trap towards the enclosure wall of the trap are retained between converging side and base walls.

It is also preferred that the inlet opening or a plurality of inlet openings be formed in the top portion of the enclosure net. The or each opening may be oval, rectangular or triangular or other shape as desired, however, the or each opening preferably has a lower edge which extends substantially parallel to the base wall.

This arrangement has the advantage that if the tubular enclosure net is damaged in use, it may be easily replaced. Furthermore replacement nets may be provided to 15 enable fishermen to assemble or repair their own pots. Of Scourse conical enclosure nets may be formed or woven if desired. Accordingly in another aspect this invention Sresides in an enclosure net for trap means substantially as defined above.

In order that this invention may be more readily ounderstood and put into practical effect, reference will now 0o0 be made to the accompanying drawings which illustrate a typical embodiment of this invention and wherein:- FIG. 1 is a perspective view illustrating the crab trap in its operative attitude; FIG. 2 is a side view illustrating the trap with the base wall released for discharge of crabs from the trap, and 0 FIG. 3 is a perspective view of the trap in its folded attitude.

As shown, the trap 10 comprises a length of tubular net 9 supported Lbout a base hoop 11. The net 9 is provided with a lower drawstring 12 and an upper tie string 13 which close the open ends of the tubular net 9 at opposite sides of ii.

the hoop 11. The lower drawstring 12 is provided with a hook 14 which can be hooked about the hoop 11 to hold the lower end of the net 9 in its closed attitude so as to form the base wall 8 of the trap 10. The upper tie string 13 passes through an aperture in the upper end of a supporting strut to enable the upper end of the net 9 to be closed and pulled upwardly along the strut 15, the lower end of which is apertured and supported by a tension cable 16 which extends diametrically across the hoop 11. The cable 16 passes through the strut so as to hold the lower end of the strut substantially centrally in the plane of the base wall 8. For this purpose, the cable 16 is knotted at opposite sides of the strut so as to prevent the lower end of the strut moving sideways therealong.

This arrangement supports the strut 15 whereby it may pivot from a stowed attitude as shown in FIG 3, at which it lies on top of the base wall 8 of the trap 10, to an o operative supporting attitude at which it extends upwardly u4 4( -v 6 from the base wall 8 as shown in FIGS 1 and 2, and forms a support for the enclosure net 9. The top portion of the net 9 forms a cone like enclosure 18 which extends upwardly from the base wall 8 to the strut 15. The side walls 19 of the enclosure 18 are provided with a plurality of triangular shaped inlet openings 20 which are cut into the net 9 and framed with suitable cord. Bait holding means such as a hook may be secured to the strut 15 above the base wall 8 to enable bait to be secured within the trap In use, the trap 10 is stowed with the bottom drawstring 12 pulled to its closed position and with the hook 14 retained about an edge portion of the hoop 11. When the trap is required to be set the upper tie string 13 is pulled upwardly to stretch the top net portion along the strut which pivots upwardly to support the enclosure net which forms the enclosure 18. The tie string 13 is then tied about the upper end of the strut 15 to hold the net 9 in position.

The bait is passed through an inlet opening 20 and secured to the retaining mrans provided on the strut. The trap is then 20 ready for use.

S°,0 To ensure that the trap 10 lands base down when placed in the water, lead weights 21 may be arranged around the frame 11 and if desired a slit plastic tube may be engaged about the net 9 where it extends across the hoop 11 25 so as to protect the net 9 a4ainst chafe. After the trap has 4 been set crabs will pass into the trap through the openings and then as they move away from the bait they will engage the downwardly inclined side wall 19 of the enclosure net 18 and move outwardly until they become sandwiched between the converging side wall 19 and base wall 8. Once in this position the crabs will remain placid and will not tend to struggle to free themselves from the net. Thus they will cause minimal damage to the net.

When the trap is raised the trapped crabs can be released simply by releasing the hook 14 from the hoop 11 so that the lower end of the net can open, as illustrated at 17 in FIG 3, to enable the crabs to spill therefrom into a suitable receptacle. Preferably the net 9 has a relatively small mesh so as to prevent entanglement therein of the crab's claws and legs. Of course the net may be formed of flexible twine or the like or of wire mesh and if desired the trap may utilize a rigid non-folding frame. Of course traps according to this invention may be used for trapping fish and prawns and the like as well as crabs and any reference herein to crabs is to be taken as a reference to same.

It will of course be realised that the above has been given by way of illustrative example of the present invention and that all modifications and variations thereto as would be apparent to persons skilled in the art are deemed to fall a within the broad scope and ambit of this invention as is 000 defined in the appended claims.

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Claims

2. A trap as claimed in Claim 1, wherein said base wall assembly is a net wall assembly and includes:- a perimeter frame; an open ended tubular net having one open end fixed to the perimeter frame and the other open end constituting said closable trap outlet, and a drawstring associated with said other open end whereby said closable trap outlet may be drawn by said drawstring to a closed attitude and which drawstring may be released to o open said closable trap outlet. to .O
3. A trap as claimed in Claim 2, wherein said drawstring is provided with catch means whereby said drawstring may be secured to maintain said other open end in said closed Sattitude.
4. A trap as claimed in Claim 3, wherein said catch means is engageable with said perimeter frame to maintain said other open end in said closed attitude. A trap as claimed in any one of the preceding claims, wherein said net supporting means includes a strut pivotable 9 from a folded position at which said strut extends across said base wall assembly to a supporting position at which said stru- extends upwardly from said base wall assembly.
6. A trap as claimed in any one of claims 2 to wherein said net is in the form of a sleeve which is secured to said perimeter frame intermediate its open ends, the upper portion of said sleeve forming said net enclosure and the lower portion of said sleeve constituting said open ended tubular net. o e~ S7. A trap as claimed in Claim 6, wherein said net is o substantially cylindrical and its open end. are each provided with a drawstring.
8. A trap as claimed in any one of the preceding claims, wherein said trap inlet opening has a lower edge which extends substantially parallel to said base wall assembly.
9. A trap as claimed in any one of the preceding claims, wherein said base wall is circular and there are provided a plurality of trap inlet openings arranged in Scircumferentially spaced relationship about said enclosure net. a A trap as claimed in any one of the preceding claims, wherein said enclosure net is provided with a stiffening frame which is raised with said net enclosure above said base wall assembly when said enclosure is elevated by said net supporting means.
11. A trap substantially as hereinbefore described with reference to the accompanying drawings. I S DATED THIS thirteenth DAY OF February, 1991. r \DESMOND PETER BIRKS PIZZEY COMPANY PATENT ATTORNEYS