TECHNICAL FI ELD

The present invention relates to apparatus for shucking oysters and , in particular, to an improved knife for sh ucking oysters. More particularly, the present invention relates to a knife for shucking oysters which are held in a stable position by an oyster shucking apparatus. BACKGROUND ART

The conventional approach to shucking or opening the closed shells of an oyster to access the organism therewithin has been to use one hand to hold the oyster and another hand to hold a knife that is used to separate one shell from the other and, in most cases, to separate the organism from the muscle that fixes it to one of the shells. This is normally achieved by causing the tip of the knife blade to penetrate the weakest point of the unopened oyster which is at the location of the valve, manipulating the position of the knife to separate the upper and lower shells, and then sweeping the blade of the knife along one side of the oyster between the shells to sever the muscle, whereby the oyster is opened and taken to the next stage of its processing. After this process of shucking the oyster, a stream of water is allowed to fall over the hands, knife, and oyster to remove any shell debris or other material that may contaminate the finished product.

Australian Patent Application No. 2OO8 230 O36 (incorporated herein by reference) of the present inventor describes an apparatus for shucking oysters that removes the need to use one hand to hold an oyster d uring the shucking process and so avoids certain injuries that may result from a knife held in the other hand injuring the hand holding the oyster. Not only is the likelihood of injury reduced, but the worker's level of comfort is increased , which results in increased overall speed and level of productivity. DISCLOSURE O F I NVENTI ON

It has been found by the present inventor that the shucking process, when utilizing the inventor's earlier oyster shucking apparatus, can be further improved by using a knife that is safer, more comfortable to use, and more efficient in shucking oysters which are held by the aforementioned oyster shucki ng apparatus.

Accord i ng to the i nvention, there is provided a knife for shucki ng an oyster, comprisi ng a handle having a first longitudinal axis, a blade having a second longitudinal axis, a guard plate connected at one side thereof to the handle and at the other side to the blade, the longitudinal axis of the blade being offset from the longitudinal axis of the handle.

Preferably, the guard plate has a generally ci rcular rim and the blade is connected adjacent to the πm.

It is preferred that the generally circular rim of the g uard plate has a diameter that is greater than a diameter of a forward portion of the handle where a user's i ndex fi nger or thumb holds the handle.

In a preferred form, the rim of the guard plate has a guard portion that extends beyond the rim of the forward portion of the handle.

It is also preferred that the guard plate has an axis of symmetry, and the axis of the guard plate is offset from the longitudinal axis of the handle. BRI EF DESC RI PTI ON OF THE DRAWINGS

In order that the i nvention may be more readily understood and put into practical effect, reference will now be made to the accompanying drawings, in which:-

Fig . 1 is a side view of an oyster shucking knife according to a first preferred embodiment of the invention,

Fig. 2 is an enlarged front view of the knife of Fig. 1 ,

Fig. 3 is a side view of an oyster shucking knife accordi ng to a second preferred embod i ment of the invention ,

Fig . 4 is an enlarged front view of the knife of Fig. 3,

Fig . 5 is a side view of an oyster shucking knife according to a third preferred embodiment of the invention,

Fig. 6 is an enlarged front view of the knife of Fig . 5 ,

Fig. 7 is a perspective view of the knife of Fig. 1 in a first orientation being used in a fi rst step to shuck an oyster held by an oyster shucking apparatus,

Fig . 8 is a perspective view of the knife of Fig. 1 in a first orientation being used in a second step to shuck the oyster,

Fig . 9 is a perspective view of the knife of Fig. 1 in a second orientation bei ng used in a third step to shuck the oyster, and

Fig. 10 is a perspective view of the knife of Fig. 1 in a second orientation being used in a fourth step to shuck the oyster. MODES FOR CARRYI NG OUT THE I NVENTION

The oyster shucking knife 1 O shown in Figs 1 and 2 has a handle 12, a blade 1 4 and a guard plate 16 connected at one of its sides to the handle and at the other side to the blade. The bl ade 1 4 has a constricted neck portion 1 8 and an enlarged cutting portion 2O. An inner side of the cutting portion has a flat surface 22 and an opposite outer side has a generally rounded or part- rounded surface 24.

The guard plate 1 6 is, in this embod i ment, made of stainless steel and is welded to the blade, which is also made of stainless steel .

The handle 12 has a first longitudinal axis 26 and the blade 14 has a second longitudinal axis 28 (as seen in Fig. 2). The axes 26, 28 are offset. This allows a user of the knifel O to have improved ability to manipulate the knife, as rotating the handle about its longitudinal axis will cause the blade to rotate in an orbit about that axis, thereby allowing the blade to change orientation more easily and with improved cutting effect.

The guard plate 16 has a generally circular rim 30, and the blade 14 is welded adjacent to the rim.

The generally circular rim 30 of the guard plate 16 has opposed portions 34 behind which there are opposed forward portions 36 of the handle 12, at one of which a user's index finger may be located when holding the handle. The shapes of the guard plate 16 and handle 12 are such that the opposed rim portions 34 of the guard plate have a diameter that is greater than the maximum diameter of the forward portions 36 of the handle. This allows the user's fingers, and particularly the index finger, to be protected against cutting by sharp edges of the oyster.

The oyster shucking knife 4O shown in Figs 3 and 4 has a handle 42, a blade 44 and a guard plate 46 connected at one of its sides to the handle and at the other side to the blade. The blade 44 has a constricted neck portion 48 and an enlarged cutting portion 5O. An inner side of the cutting portion has a flat surface 52 and an opposite outer side has a generally rounded or part- rounded surface 54.

The handle 42 has a first longitudinal axis 56 and the blade 44 has a second longitudinal axis 58 (as seen in Fig. 4). The axes 56, 58 are offset.

The guard plate 46 has a generally circular rim 60, and the blade 44 is welded adjacent to the rim. The generally circular rim 60 has an axis of symmetry 62 (as seen in Fig. 4). The axes 56, 62 are offset by a distance "X"

as shown. This allows a user of the knife 40 to have improved ability to manipulate the knife, as rotating the handle about its longitudinal axis will cause the blade to rotate in an orbit about that axis.

The generally circular ri m 6O has opposed portions 64 behind which there are opposed forward portions 66 of the handle, at one of which a user's index finger may be located when holding the handle. The shapes of the guard plate 46 and handle 42 are such that the opposed rim portions 64 of the guard plate have a diameter that is g reater than the maximum d iameter of the forward portions 66 of the handle. This allows the user's fingers, and particularly the index finger, to be protected against cutting by sharp edges of the oyster.

The oyster shucki ng knife 70 shown in Figs 5 and 6 has a handle 72, a blade 74 and a guard plate 76. Unless otherwise described, the oyster shucking knife 70 has the same features, and functions in the same manner, as the oyster shucking knife 1 0 and the oyster shucking knife 40. The handle 72 has a first longitudinal axis 86 and the blade 74 has a second longitudinal axis 88 (as seen in Fig. 6). The axes 86, 88 are offset.

The guard plate 76 has a generally circular rim 90 and the blade 74 is welded adjacent to the ri m. The generally circular rim 9O has an axis of symmetry 92 (as seen in Fig. 6). The axes 86, 92 are offset by a distance "X" as shown.

The handle in each of the embod i ments descri bed above is preferably inflexible and may be made of stainless steel.

As shown in Figs 7 to 10, the knife 10 can be used in four basic steps to shuck an oyster held in an oyster shucking apparatus 270. The knives 4O and 70 can also be used in a si milar manner.

In use, a person holds the knife 10 in one hand in a first orientation and pushes the tip of the knife blade 301 into the valve between the upper and lower shells 302, 303 of an oyster 272 in the direction of arrow A, thereby penetrating the weakest point of the oyster (see Fig . 7).

The blade 301 of the knife is then pushed down in the direction of arrow B, thereby partly separating the upper and lower shells of the oyster (see Fig. 8).

Further separation of the shells is achieved by then twisting the blade 301 of the knife i n the direction of arrow C to achieve a second orientation , and so as to locate a cutting edge 304 of the blade uppermost and in a leading position agai nst the upper shell of the oyster (see Fig. 9).

The blade 301 is then swept rearwardly along the inside of the oyster between the shells in the direction of arrow D to cause the cutting edge 304 of the blade to sever the muscle holding the shells together, whereby the oyster is opened.

It wi ll be readily apparent to persons skilled i n the art that various modifications may be made in details of design and construction of the knives described above without d eparting from the scope or ambit of the present invention.

For instance, the handle, rather than having a curved surface, may be a square section tube made of stainless steel , and have a height of 2O mm, a width of 20 mm, and a length of 12 cm. The inflexi bility of the handle prevents the handle bending when the ti p of the knife blade is initially pushed i nto the valve of the oyster. Any bending of the handle will absorb some of the force applied through the hand of a person holding the knife and will delay the application of the full amount of force required to open the valve. Such a delay may allow the oyster to react quickly enough to apply optimal resistive force on the valve, thereby making penetration by the knife through the valve more difficult and time consuming.