AU2003100530A4 - A Shellfish Cultivation Cage - Google Patents

Description

AUSTRALIA

Patents Act 1990 INNOVATION PATENT SPECIFICATION Name of Applicant Address for Service: Invention Title: Tooltech Pty Ltd CULLEN CO Patent Trade Mark Attorneys, 239 George Street Brisbane QId 4000 Australia A Shellfish Cultivation Cage This invention is described in the following statement: Field of the Invention The present invention relates generally to cages and, in particular, to cages that are used to cultivate shellfish.

Although the invention will be described with particular reference to being used to cultivate oysters, it will be appreciated that the invention may be used to cultivate other types of shellfish such as scallops and sea urchins.

Brief Discussion of the Prior Art Over the years various techniques have been developed for cultivating oysters. One such technique entails placing infant oysters, called spats, into a mesh cage that has a float or floats attached to it. The cage and floats are then placed into the water in which the oysters are to be cultivated or grown-out. The buoyancy of the floats is sufficient to maintain the cage afloat near the water's surface so that the oysters are located just beneath the surface where they normally experience the highest growth rates.

A prior art floating cage 10 for cultivating oysters is illustrated in Fig. 1. The cage 10 is in the form of rectangular mesh bag 11 having a pair of cylindrical foam floats 12, 13 secured to opposite sides thereof with cable ties 14. Access to the interior of the bag 11 is provided by a hinged closure flap 15. The flap 15 is secured in place by a pair of clips 16 to prevent oysters from falling out of the bag 11 or predators from gaining access to the oysters.

The cage 10 suffers from the disadvantage that the construction of the mesh bag 11 is separate from the attachment of the floats 12, 13 to the bag 11. This two-step construction can add significantly to the time and therefore cost involved in manufacturing the cage 10 in the large quantities that would be required for a commercial oyster farm.

It is an object of the present invention to provide a shellfish cultivation cage that overcomes, or at least ameliorates, one or more of the deficiencies of the prior art shellfish cultivation cage mentioned above, or that provides the consumer with a useful or commercial choice.

Other objects and advantages of the present invention will become apparent from the following description, taken in connection with the accompanying drawings, wherein, by way of illustration and example, an embodiment of the present invention is disclosed.

Summary of the Invention According to an aspect of the present invention there is provided a shellfish cultivation cage including a top mesh panel, a bottom mesh panel, a pair of opposing end walls, and a pair of opposing side walls provided by floatation members sandwiched between and secured relative to the top and bottom panels, the floatation members being sufficiently buoyant to maintain the cage afloat in water.

The cage according to the present invention has the advantage over the prior art discussed above in that the floatation members form an integral part of the cage such that the construction of the cage and the attachment of the floatation members is done at the same time.

Preferably, the end walls of the cage are provided by closure flaps hinged to the top and/or bottom panels. The closure flaps are preferably mesh panels.

In a preferred form the floatation members are constructed from buoyant foam such as polyolefine foam.

Brief Description of the Drawings In order that the invention may be more fully understood and put into practice, a preferred embodiment thereof will now be described with reference to the accompanying drawings, in which: Fig. 1 is a top perspective of a prior art shellfish cultivation cage; Fig. 2 is a top perspective of a shellfish cultivation cage according to an embodiment of the present invention; Fig. 3 is similar to Fig. 2 except that the closure flaps of the cage are open; Fig. 4 is an end perspective of the cage illustrated in Fig. 3; Fig. 5 is a side perspective of the cage illustrated in Fig. 3; Fig. 6 is a perspective of a portion of the side of the cage illustrated in Fig. 3; and Fig. 7 is a similar to Fig. 6 except that the closure flaps of the cage are closed.

Detailed Description of the Preferred Embodiment Referring to Fig. 2, a shellfish cultivation cage 20 according to an embodiment of the present invention includes a top panel 21, a bottom panel 22, a pair of opposing end walls 23, 24, and a pair of opposing side walls 26.

The top and bottom panels 21, 22 are identical to each other and each panel 21, 22 is in the form of a rectangular section of injection-moulded plastic mesh. The mesh is sufficiently small to prevent shellfish of a particular minimum size from falling through the panels 21, 22 and escaping from the cage 20. For example, if oyster spats were to be placed inside the cage the mesh would need to be small enough to prevent the spats from falling through the panels 21, 22.

Each panel 21, 22 has a pair of integrally formed and opposing closure flaps 27 that are hinged thereto by a plurality of hinges 28 (see Fig. 6) such that the flaps 27 can be pivoted in either direction relative to the panel 21, 22 to which they are hinged. The flaps 27 are thinner than the panels 21, 22 to which they are hinged and they also each have an edge formation 29 located on one of their faces.

The side walls 25, 26 are each provided by a respective elongate floatation member 40. Each floatation member 40 consists of a length of buoyant polyolefine foam material having a rectangular transverse crosssection.

The cage 20 is assembled by firstly positioning the floatation members 40 adjacent the sides of the bottom panel 22. The top panel 21 is then placed on top of the floatation members 40 such that the floatation members 40 are also adjacent the sides of the top panel 21 and are sandwiched between the panels 21, 22. Moreover the top panel 21 and the bottom panel 22 are arranged such that the edge formations 29 of the panels 21 face in the same direction. After the panels 21, 22 and the floatation members 40 have been arranged in this way the floatation members 40 are then secured relative to the panels 21, 22 with cable ties 41 in the manner illustrated in Figs. 3 to 6.

Referring to Fig. 7, the end walls 23, 24 of the cage 20 are provided by the closure flaps 27 and are formed by pivoting the closure flaps 27 of the bottom panel 22 relative to that panel until those flaps 27 overlie the ends of the flotation members 40. The closure flaps 27 of the top panel 21 are then pivoted until those flaps 27 overlie the closure flaps 27 of the bottom panel 22. In particular, the flaps 27 are pivoted until they overlie each other sufficiently to contact each other with their respective edge formations 29.

The flaps 27 can then be secured in position with cables ties 42.

Prior to closing the cage 20 with the flaps 27, oyster spats that are to be grown-out are placed inside the cage 20. After the flaps 27 have been closed and secured the cage 20 is placed in the water in which the oysters are to grown. The flotation members 40 are sufficiently buoyant to maintain the cage 20 afloat in the water with the bottom panel 22 located near to the water's surface so that the oysters in the cage 20 are also situated near the surface.

The design of the cage 20 is advantageous in that the floatation members 40 form an integral part of the cage 20 so that the construction of the cage 20 and the attachment of the floatation members 40 are performed simultaneously.

Also, by using identical top and bottom panels 21, 22 that have hinges 28 that enable the closure flaps 27 to be pivoted in both directions enables the tool-up costs required to produce the panels 21, 22 to be minimised as a single mould can be used to produce both panels 21, 22.

Moreover, the configuration of the various components of the cage 20 is such that they occupy a minimal amount of space when disassembled which can result in significant cost savings when freighting the disassembled components.

The foregoing describes only one embodiment of the present invention and modifications, obvious to those skilled in the art, can be made thereto without departing from the scope of the present invention. For example, although the cage 20 was described above with the panel 21 being the top panel and the panel 22 being the bottom panel, this could be reversed so that the panel 21 is the bottom panel while the panel 22 is the top panel.

Also, the panels 21, 22 could be modified so that there is only one closure flap 27 at either end of the cage Moreover, it is conceivable that there may not be any closure flaps 27 hinged to the panels 21, 22 at either end of the cage 20 so that the end walls 23, 24 would need to be provided by securing a suitable cover over the end or ends of the cage Further, the closure flaps 27 may be provided by mesh panels so that water may flow through them.

The floatation members 40 need not be constructed from buoyant foam and may for example be provided by sealed tanks containing air.

Also, floatation members 40 providing different levels of buoyancy may be used to vary the buoyancy of the cage 20 to suit different applications and conditions.

Additionally, the size of the panels 21, 22 and the size of the floatation members may be varied to vary the size of the cage Further, the panels 21, 22 may be constructed from other materials and may have other configurations. For example, the size and configuration of the mesh may be different. The sides of the panels 21, 22 may have solid edging. Also, a different number of hinges 28 may join the closure flaps 27 to the panels 21, 22.

The floatation members 40 and the closure flaps 27 need not be secured in place with cable ties 41, 42 and may instead be secured with other fastening devices such as clips.

Claims (4)

1. A shellfish cultivation cage including a top mesh panel, a bottom mesh panel, a pair of opposing end walls, and a pair of opposing side walls provided by floatation members sandwiched between and secured relative to the top and bottom panels, the flotation members being sufficiently buoyant to maintain the cage afloat in water.

2. The cage of claim 1 wherein the end walls are provided by closure flaps hinged to the top and/or bottom panels.

3. The cage of claim 2, wherein the closure flaps are mesh panels.

4. The cage of any one of claims 1 to 3, wherein the floatation members are constructed from a buoyant foam. A shellfish cultivation cage substantially as herein described with reference to Figs. 2 to 7 of the drawings. DATED this 1 st day of July 2003 Tooltech Pty Ltd By their Patent Attorneys CULLEN CO.