Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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BACRGROUND OF THE INVBNTION
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The present invention relates to an apparatus for use in
facilitating the processing of sea urchins or other similar shelled
creatures, and more particularly relates to a tool which may be
5 used to open the shell of a sea urchin to facilitate removal of its
gonads.
A sea urchin is a small, bulbous, spiny Echinoderm. It
has a mouth and an anal pore located respectively on the bottom and
top of the shell in its geometric centre. The urchin attaches
10 ltself to various kelps, which it feeds upon, or other sea bottom
ob~ects. ~ ;
Most of the urchin is unusable for food. The part that
is utilized i8 the gonad, both male and female. ~oe contained
within the gonadal sack iB regarded by many as a delicacy akin to
caviar. :
There are several problems associated with the removal of
tha gonads from sea urchins:
(1) The gonads are encased in a spiny calcareous shell.
(2) The gonads are surrounded by viscerae which serve to
soil the gonads when disturbed.
(3) The gonads are attached to the shell in two ways: - ~
- The gonads are held in place by a sinuous ; ;
tendon which extends from the top of the sack ;~
to a circular area surrounding the anal pore.
- They are held as well by a tissue to tissue
bond on the inside of the urchin shell. ~-
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The aesthetics of the product sold to consumers are as
important as the palatability of the product. For this reason, any
process that is used to remove the gonads must guarantee gonadal
sacks are not damaged. Only high quality sacks receive best prices
from consumers.
The presently employed method of opening sea urchin
shells is to split the shells using a hand tool in the form of a
knife or chisel and to scoop out the gonads using a tool like a
~poon. The process is messy and time consuming due to long removal
and clsaning times.
Canadian Patent No. 1,150,456 of O'Donnell issued
July 26, 1983 describes and illustrates a mechanical apparatus for
facilitating the cracking of sea urchin shells. That apparatus
incorporates a blade, spring mounted for depression onto the shell
of a sea urchin held on a plate below, the blade being formed with
a central recess to facilitate penetration of the sea urchin shell
in the region of the mouth. The blade and the shaft on which it
is mounted are pivotally supported so as to break a cracked sea
urchin shell open.
It is an object of the present invention to provide a
devlce which will automate the sea urchin gonad removal process.
It is a further object of the present invention to provide such an
apparatus which will, in conjunction with another apparatus
described and illustrated in my co-pending patent application
Serial No. , produce a high quality product for consumers
and significantly reduce labour coæts and facilitate the removal of
sea urchin gonads.
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UMMA~Y OF THE INVENTION
In accordance with the present invention there is
provided an apparatus for opening the shell of a sea urchin or like
shelled creature comprising a hole saw having a cylindrical blade
with teeth on an expo~ed end of the blade rotatable about an axis,
the hole saw operable to drill a hole of predetermined diameter
through an area of the shell, and means associated with the hole
saw to support the shell to be opened and expose to the hole saw
the area of its shell in which the hole is to be drilled. The
apparatus further comprises a means associated with the hole saw
and the support means to permit relative movement thereof into
operative position whereby the saw blade and shell are in contact
so as to enable drilling of the hole, and relative movement thereof
lnto non-operative position with the saw blade clear of the shell.
In a preferred embodiment of the present invention, a
pressure plate i8 associated with the hole saw, in operation to
~upport the shell. The pressure plate has an aperture through
which the saw blade is to project during operation. Means are
provided to permit relative movement of the pressure plate and the
hole saw during operation so that the saw blade extends through the
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pressure plate aperture to cut a hole in a shell supported on the
pressure plate. ~
The apparatus according to the present invention provides ~"
a good initial cut into the urchin shell, which cut, when centred
about the mouth section of the sea urchin, completely removes that
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mouth section and exposes the gonads for subsequent removal, while
not damaging the gonads in any way. While effective on sea urchins
the apparatus of the present invention is also useful on scallps -~
and possibly other shellfish.
BRIEF DE~CRIPTION OF T~ DRAWINGB
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These and other objects and advantages of the invention
will become apparent upon reading the following detailed
description and upon referring to the drawings in which:
FIGURE 1 is a perspective view of a hole saw apparatus
for opening the shell of a sea urchin in accordance with the
present invention.
FIGURE 2 is a partial section view through the wall of
the hole saw blade and support tube in FIGURE 1, illustrating the
manner in which the blade is secured to the support tube; and
FIGURES 3A and 3B are respectively front (from the
inside) and side views of a preferred profile for the teeth of the
saw blade of the apparatus of the present invention.
FIGURE 4 is a side view, in partial section of the -
apparatus of FIGURE 1.
While the invention will be described in conjunction with
an example embodiment, it will be understood that it i5 not
intended to limit the invention to such embodiment. On the
contrary, it is intended to cover all alternatives, modifications
and equivalents as may be included within the spirit and scope of -~
the invention as defined by the appended claims.
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DETAILED DE~CRIPTION OF THE INVENTION ;
In the drawings, similar features have been given similar
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reference numerals. ;
Turning to Figures 1 and 4 there is illustrated an
apparatus 2 for opening the shell 4 of a sea urchin or like shelled
creature. Apparatus 2 comprises a hole saw blade 6 of appropriate
material (e.g. steel acceptable to regulatory agencies) releasably
secured to a support tube 8 for rotation about an axis of rotation
X (Figure 4), Snap-on guides 10 in the lower walls of saw blade 6
co-operating with rivets 12 on support tube 8 (Figure 2), or any
other conventlonal means may be used to releasably hold blade 6 on
tube 8. An appropriate conventional drive means 14 is used to
rotate tube 8 and blade 6 during operation.
At the upper end of hole saw blade 6 is a plurality of
teeth 16, a preferred form of which is illustrated in Figures 3A
and 3B. As can be seen in these figures, the outer edges 18 of
teeth 16 are bevelled to a point, from the inside surface 20 to the
outside (Figure 3A). As can be seen in Figure 3B, the teeth are
slightly inwardly tapered on their inside surface 20, from the
bottom to top. The teeth are outwardly pointed in a direction
parallel to the axis of rotation X. It has been found that such a
saw blade, turning at from about 200 rpm to about 10,000 rpm
(increased spacing of the teeth requiring an increased speed) will
effectively cut open the mouth area of the shell 4 of the sea
urchin. Hole saws of diameters ranging from 1 inch to 2 inches ;
have been found to be effective, although the preferred diameter is
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about 1 3/4 inch. The blade is preferably of about 1/8 inch in
width and made of stainless steel.
In conjunction with hole saw blade 6 and support tube 8
there is a pressure plate 22 having a centred aperture 24, plate 22
to receive a sea urchin shell 4 in centred fashion so that the area
of shell 4 to be opened lies exposed through aperture 22, through
which aperture teeth 16 of blade 6, as will be described in more
detail subsequently, are to extend. Pressure plate 22 is supported
on a table 26 by means of a plurality of compression springs 28,
extending between the plate and table about their periphery as
illustrated. Table 26 is also provided with an aperture 30,
~imilar to and aligned with aperture 24 of pressure plate 22.
Table 26 is supported by an appropriate frame 32 as illustrated,
with support tube 8 and blade 16, during operation, rotatable and
movable along the axis of rotation with respect thereto, as
illustrated. Compression springs 28 permit pressure plate 22 to be
depressed against their bias a limited amount such that, during
operatlon, teeth 16 of blade 6 can contact the shell 4 of the sea
urchin and cut a clean hole through it. Downward pressure on
pressure plate 22 may be provided manually, for example, by
pressing the sea urchin supported on pressure plate 22 downwardly,
or by appropriate mechanical means. After the cut has been made,
removal of the pressure on pressure plate 22 or shell 4 by the
operator or a mechanical means will cause compression springs 28 to
return to their original state, elevating pressure plate 22 so that
shell 4 is now clear of teeth 16 of blade 6.
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In operation, it has been found that the sea urchin shell
4 may be quickly and easily opened using apparatus 2 in accordance
with the present invention. A uniform smooth hole in shell 4 is
created in the desired, bottom area of the urchin which completely
removes the mouth section and exposes the gonads 32 (Figure 2)
while not damaging the gonads in any way. The process works well
for different diameter hole saws, it having been found that
generally there are not mouth sections of sea urchins which are of
greater diameter than 1 1/8 inches. A 1 3/4 inch diameter hole saw
blade cannot be used on some of the smaller urchins, it has been
found, ~ince the blade encompassed the whole urchin. Nevertheless
that blade has been ~ound to be the optimal blade for most normal
sized urchins.
When a hole has been drilled using the apparatus 2 in
ac¢ordance with the present invention in the shell of a sea urchin,
~haking the urchin in a downward movement removes viscerae only.
Most of the gonad sacks 34 remain intact inside the urchin shell.
The gonads are now ready for removal using the apparatus described
in my co-pending application Serial No.
The use of the apparatus according to the present
invention in the initial opening procedures provides a very
,
effective method for commencement of the gonad removal procedure.
ThiC apparatus permits the mouth ~tructure of the sea urchin to be
removed allowing easy access to the gonads. The body fluid of the
sea urchin washes away any dust or splinters that are created
through the drilling operation. The viscerae are allowed to drop
out leaving relatively clean gonads. The uniform hole thus created
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in the shell of the sea urchin provides smooth sides for easier
subsequent automation of the gonad removal process. The apparatus
of the present invention exposes the gonads for easier quality
control prior to their removal.
Thus it i8 apparent that there has been provided in
accordance with the invention that fully satisfies the objects,
aims and advantages set forth above. While the invention has been
described in conjunction with a specific embodiment thereof, it is
evident that many alternatives, modifications and variations will
be apparent to those skilled in the art in light of the foregoing
description. Accordingly, it is intended to embrace all such
alternatives, modifications and variations as fall within the
spirit and broad scope of the invention.
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