Note: Descriptions are shown in the official language in which they were submitted.
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LOIN PULLER WITH TWO SEPARATE CUTTING BLADES
FIELD OF THE INVENTION
The present invention relates to a loin puller of improved structure,
which comprises a cutting tool having two blades instead of one only, in order
to trim off the backfat from a loin while leaving the so cut backfat attached
to
the belly.
BACKGROUND OF THE INVENTION
Loin pullers are well known machines used in the meat processing
industry for trimming off the backfat of a loin, in particular a pork loin.
As shown in Fig. 1 of the accompanying drawings, the central part
or "middle" of the carcass-half of a piece of meat comprises two main parts
respectively called "loin" and "belly". The loin is adjacent to the cut
portion of
the spinal column. The front portion of the loin contains ribs which are
called
"back ribs". The belly which is also called "flank", is a part which is
adjacent
to the loin at the opposite of the spinal column. The ends of the ribs which
extend along the belly can altogether be separated from the same to form
"spare ribs", or they can be removed individually. After removal of the ribs,
the belly is mainly used to prepare bacon. The whole carcass-half is covered
by an external layer of fat which extends under the loin and belly. The
thickness of this layer of fat depends on several parameters including, inter
alia, the size, the origin and the nutrition of the animal. This fat is the
one that
can be found in bacon. Therefore, it is important from a practical standpoint
to keep a proper amount of fat with the belly prior to cutting the same.
However, it is important to remove some of the fat extending under the loin to
avoid an over load of fat in the final product and have to call for an extra
manpower or a complementary equipment to remove this fat if it has not
been removed from the loin in the loin puller.
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Prior to processing a loin in a loin puller, it is of course necessary
to separate it from the belly. So far, there have been two different methods
of
doing so.
The first method, called "Canadian cut", consists in completely
separating the belly from the loin by completely cutting the carcass-half
according to a suitable cutting line which may vary depending on the need.
An example of such a cutting line is shown in dotted lines in Fig. 1. Such a
cutting can be carried out either manually or by means of another machine
located upstream the loin puller or within the same. Once separated, the belly
zo can be directed towards another machine or another working table specially
adapted for this purpose, in order to separate the spare ribs. On the other
hand, the loin is introduced into the loin puller, in order to trim off its
fat.
As a non-limitative example of a loin puller especially adapted to
process loins after full separation from the adjacent bellies, reference can
be
made to U.S. patent No. 5,090,939 issued on February 25, 1992 in the name
of the Applicant, G.E. LEBLANC INC.
The second method, called "American cut", consists in cutting
(scribing) only the internal part of the carcass-half, that is the upper part
of
the carcass-half shown in Fig. 1, following the same type of cutting line as
above, except for the fat. As a result, the layer of fat remains uncut and
maintains altogether the loin and the belly. Then, both of them may be
transferred together to a working table where the loin is separated from the
belly while leaving some of the loin fat attached to the belly. The main
advantage of this method is that it makes it possible to recover part of the
fat
and meat of the loin together with the belly, which part would otherwise have
been left onto the loin and trimmed off by a cutting blade. Usually, this
method of processing carcass-halves is carried out manually, even though
industrial machines have been proposed to do it.
As a non-limitative example of a loin puller adapted to process
loins not fully separated from the adjacent bellies, reference can be made to
U.S. patent No. 6,336,856 issued on January 8, 2002 also in the name of
G.E. LEBLANC INC.
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In all the existing loin pullers whatever be their kinds of cut, viz.
Canadian or American ones, it is of common practice to use an arcuate
cutting blade mounted above the loin conveying system in order to engage
the loin while the same is moved forwards, and to cut the layer of fat to be
s trimmed off from the same, with or without lean meat on the trimmed fat
attached to the belly. The arcuate cutting blade is of course "associated" to
a
control system whose purpose is to adjust the height and curvature of the
blade as a function of the size, shape and other characteristics of the loin
to
be processed, especially the thickness of the layer of fat to be trimmed off.
1o This control system can be operated manually or it can be operated by an
automatic measurement system which evaluates the main parameters
required for adjusting the cutting blade as a function of the evaluation of
the
main parameters from trimming off the loin. For further details on this kind
of
automation, reference can be made by way of non-restrictive examples to the
15 description of the above mentioned U.S. patent No. 5,090,939.
In order to maximize yields on bellies as compared to what is
achieved when use is made of a conventional arcuate cutting blade, it has
already been suggested to use an arcuate cutting blade having a distorted
portion (also called "inwardly projecting bend" or "indented bight") on one of
20 its sides. In this connection, reference can be made to the above mentioned
U.S. patent No. 6,336,856 to G.E. LEBLANC INC., as well as to U.S. patent
No. 6,155,919 issued on December 5, 2000 to SWIFT & CO. and U.S. patent
No. 6,089,968 issued on July 18, 2000 to ACRALOC CORP. Reference can
also be made to U.S. patent No. 6,547,658 issued on April 15, 2003 to
25 ACRALOC CORP., which discloses a loin puller comprising two blades
extending vertically within the conveyor, one of said blades being Z-shaped
to fully separate the loin from the belly while leaving lean fingers on the
belly
to increase the exposed amount of lean meat on the backfat side of the belly,
the other one of said blades being J-shaped to trim off the fat and skin from
30 the loin after it has been separated from the belly.
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In all above-mentioned cases, the utility and advantage of the
distorted portion of the blade is to allow trimming off of the loin close to
the
ribs while leaving lean fingers of meat on the belly.
It is worth noting however that there is a basic difference between
the way the arcuate cutting blade with a distorted portion disclosed in G.E.
LEBLANC's patent No. 6,336,856 is used and the way the blade disclosed in
the three other patents mentioned hereinabove, is used. In G.E. LEBLANC's
patent No. 6,336,856, the arcuate cutting blade is exclusively used to trim
off
the fat and skin (also called "backfat") from the back of the loin while
1o simultaneously leaving fingers of meat on the belly. The arcuate cutting
blade
separates the loin from the central part of the carcass half but it does not
separate the fat and skin trimmed off from the loin from the adjacent belly.
In
full contrast, in SWIFT & CO's patent No. 6,155,919 and ACRALOC CORP.'s
patent Nos. 6,089,968 and 6,547,658, the arcuate cutting blade(s) is (are)
used to fully separate not only the loin itself but also its fat and skin from
the
belly while leaving fingers of meat on the same. In U.S. patent Nos.
6,155,919 and 6,089,968, a single cutter blade is used just to separate the
loin from the belly while leaving the skin and fat intact on the back of the
loin
(see and compare Figs. 2 and 3 of U.S. patent No. 6,155,919 and Figs. 18
2o and 19 of U.S. patent No. 6,089,968 and the corresponding parts of their
specification). In U.S. patent No. 6,547,658, another blade is used to trim
off
the fat and skin from the loin. However, even if the fat and skin are trimmed
off from the loin, the fat and skin are also separated from the belly either
at
the same time or just before.
If arcuate cutting blades with a distorted portion are interesting for the
above mentioned reason, they have the drawback of being very difficult to
make in one piece with an appropriate and efficient sharpened edge. Thus, in
practice, the requested cutting especially close to the ribs without risk of
hitting them and also hitting the blade bone, is quite difficult to be
achieved
with good results, especially in the case where, like in G.E. LEBLANC's loin
puller, the arcuate part of the cutting blade is mainly used to separate the
loin
from the belly while trimming off the fat and skin from the loin and leaving
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them attached to the adjacent belly.
SUMMARY OF THE INVENTION
It has now been found that the above mentioned problem
5 encountered in a loin puller when use is made of an arcuate cutting blade
having a distorted portion, can be solved if one uses another cutting blade
separate from the arcuate cutting blade for the purpose of cutting the loin
close to the ribs to leave lean fingers of meat on the belly prior to further
processing the loin to trim off the fat and skin (also called "backfat") from
its
lo back while leaving them attached to the adjacent belly.
Thus, the invention is directed to an improved loin puller for trimming
off the backfat of a loin that has been scribed from a belly along a scribing
line, the loin comprising backribs adjacent to the scribing line. This
improved
loin puller, like the existing ones, basically comprises:
- a frame;
- a conveying system mounted onto the frame for
engaging the loin and moving it towards a cutting zone; and
a cutting tool mounted onto the frame in the cutting zone
for engaging the loin when said loin is moved by the conveying system and
for cutting the backfat to be trimmed off from the loin, with the so-cut
backfat
remaining attached to the belly,
The improvement essentially lies in that the cutting tool
comprises two blades, one of these blades being arcuate and positioned onto
the frame so as to engage at least one part of the loin from a side of the
loin
opposite to the belly, and cut the backfat to be trimmed from this part, the
other one of these blades being L-shaped and positioned onto the frame so
as to engage another part of the loin and cut the backfat to be trimmed
thereof directly from the scribing line just below the back ribs of the loin.
As may be appreciated, the invention is thus directed to an
independent dual blade loin puller that is devised to keep the backfat portion
of the loin intact and attached to the belly after the loin has been
separated.
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The capability of keeping the backfat attached to the belly
portion after separation of the loin is very important for getting the maximal
yields from the three parts of the middle, namely the belly, the loin and the
backfat. In practice, the separation line between the belly and the backfat is
s depending on multiple belly criteria which can be evaluated only after
removing the loin, such as thickness, width, lean meat content, width and
length of the fingers, commercial needs of the belly market, ,etc.... This
evaluation is usually done by trimmer operators or by new technologies such
as automatic belly trimming process.
As described in the prior art except US patent 6,336,856, the
separation of the backfat and belly is done in the loin puller by one blade or
by one or two of a set of dual blades. Consequently, this separation is done
following a predetermined width which is always at the same distance of the
scribe line whatever be the characteristics of the belly. Such may of course
substantially affect the yield of both products because the belly which has
been separated from the backfat will have to be trimmed another time after
evaluation of all the criteria described above and its yield will be lowered
if
the loin puller has removed from the belly too much fatback portion or not
enough.
Thus, the backfat portions could be too narrow or too wide, thereby
affecting the integrity and value of this product.
Of course, in the improved loin puller according to the invention, both
of the blades have to be long enough to ensure that all the backfat of the
loin
be trimmed off.
Advantageously, two independent control systems may be used for
adjusting the respective positions of the blades independently from each
other. These control systems may be operated by an automatic
measurement system which preferably comprises:
- a roller mounted onto an arm that extends vertically over the
conveying system so as to contact the loin close to the scribing line and thus
permit to determine the thickness of the loin; or
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- a laser beam that projects downwardly from the frame onto the loin
close to the scribing line so as to determine the thickness of this loin; or
- an ultrasonic system that projects downwardly from the frame onto
the loin close to the scribing line so as to determine the thickness of the
loin.
To improve the cutting, use is preferably made of an L-shaped blade
that has a vertical portion with a front cutting edge that extends at an angle
io downwardly rearwardly, and a horizontal position with a front cutting edge
of
triangular shape that extends frontwardly towards the loin that is moved by
the conveying system. Advantageously, the cutting edge of the L-shaped
blade may also be sharpened more on one side. In this connection, it has
surprisingly been found that if use is made of an L-shaped blade having its
cutting edge sharpened at an angle more on one side instead of having it
sharpened evenly on both sides, much better engagement of the blade in the
loin close to ribs may be achieved without hitting said ribs or any part of
the
shoulder blade that could still be in the piece of meat, especially when this
piece is made of soft meat. Moreover, much better results may be obtained.
To improve the cutting and make easier the maintenance of the
blades, use is preferably made also of an arcuate cutting blade that has a
front groove in which is detachably inserted a foldable piece of metal having
a front sharpened cutting edge. Such a piece may be replaced in a fast and
easy manner whenever necessary.
Preferably, the L-shaped blade extends in front of the arcuate blade in
order to cut part of the loin close to where it has been scribed, before the
arcuate blade engages the loin. In this particular case, the arcuate blade
that
extends behind the L-shaped blade may have two opposite ends connected
to the frame and be shaped so as to engage the loin and cut the backfat to
3o be trimmed thereof between the side of the loin opposite the belly and the
scribing line. Alternatively and preferably also, the arcuate blade that
extends
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behind the L-shaped blade, has only one end connected to the frame, and
another free end that extends close to the L-shaped blade.
In accordance with a particularly preferred embodiment of the
invention :
s - the L-shaped blade extends upstream of the arcuate blade in order
to cut part of the loin close to where it has been scribed, before the
arcuate blade engages said loin;
- the arcuate blade that extends behind the L-shaped blade, has one
end connected to the frame and another end that is free and extends
close to the L-shaped blade;
- the free end of the arcuate blade is pivotably connected to a pin that
projects horizontally rearwardly from the L-shaped blade; and
- the arcuate blade is flexible and the L-shaped blade is rigid.
With this particular embodiment, respective adjustments of the arcuate blade
and of the L-shaped blade by their respective control systems permit to
modify the arcuate shape of the arcuate blade and thus to adapt its cutting to
the loin to be trimmed off, thereby reducing the risk of scoring the loin
portion.
The invention and its advantages will be better understood upon
reading the following non-restrictive description of a preferred embodiment
thereof made with reference to the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
Fig. I is a perspective view of a carcass-half showing the main
parts of it, as they have been disclosed hereinabove in the "Background of
the invention".
Fig. 2 is a rear, left-hand side perspective view of the cutting zone
of an improved loin puller according to a preferred embodiment of the
invention.
Fig. 3 is a front right-hand side perspective view of the two blades
of the cutting tool of an improved loin puller according to another preferred
embodiment of the invention;
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Fig. 4 is a rear view of the cutting zone of the improved loin puller
shown in Figure 3, illustrating the respective positions of the blades of the
cutting tool, when these blades engage the loin and belly;
Fig. 5 is a rear, left-hand side perspective view of the cutting zone
of an improved loin puller according to a further preferred embodiment of the
invention;
Fig. 6 is a rear view similar to the one shown in Figure 4,
illustrating still another preferred embodiment of the invention; and
Figs. 7a to 7f are schematic rear views of the blades of the
1o improved loin puller shown in Figures 3 and 4, which Figures illustrate the
distortions that can be given to the arcuate blade of the loin puller when
this
blade is flexible and operatively connected to the L-shaped blade which is
rigid.
DETAILED DESCRIPTION OF THE INVENTION
The improved loin puller 1 according to preferred embodiments of
the invention as shown in Figs. 2 to 6, is devised for trimming off the fat
and
skin viz. the "backfat", from the back of a loin "L" scribed from a belly "B",
as
shown in Fig. 1. This improved loin puller 1 basically comprises:
- a frame 3;
- a conveying system 5 mounted onto the frame for engaging the
loin and moving it towards a cutting zone in the direction shown by the arrow
"A" in the drawings; and
- a cutting tool mounted onto the frame 3 in the cutting zone for
engaging the loin when the same is moved by the conveying system 5 and
for cutting the backfat to be trimmed off from the same with the so cut
backfat
still remaining attached to the adjacent part of the belly, as is shown in
Figures 4 and 6
As aforesaid, the improvement essentially lies in that the cutting
tool comprises two blades 7 and 9. One of these blades, namely the one
numbered 7, is arcuate and positioned onto the frame 3 so as to engage at
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least one part of the loin "L" from the side of the loin that is opposite to
the belly "B"
and to cut backfat to be trimmed off from this part.
The other one of the blades, namely the one numbered 9, is L-shaped
and positioned onto the frame, so as to engage another part of the loin "L"
and cut
5 the backfat to be trimmed thereof directly from the scribing line just below
the back
ribs "R" of the loin (see Figs. 4 and 6).
Of course, both of the blades (7, 9) must be long enough so as to ensure
that, as a result of the cuts, they respectively make in the loin "L" all the
backfat of
the loin be trimmed off.
10 In accordance with a particularly preferred embodiment of the invention
shown in Figures 4 and 6, two independent systems 23, 25 may be used for
adjusting the respective positions of the arcuate blade 7 and of the L-shaped
blade
9 independently from each other. These two control systems 23, 25 can be
operated
by an automatic measurement system, as is of common practice in the existing
automatic loin pullers (see again the U.S. patents cited in the "Background of
the
invention"). As automatic measurement system, use can be made of a system as
shown in Figure 4, which comprises a roller 27 mounted onto an arm 29 that
extends vertically over the conveying system 5 so as to contact the loin close
to the
scribing line and thus permit to determine the thickness of this loin.
Alternatively,
use can be made of a system as shown in Figure 6, which comprises a laser beam
or an ultrasonic system that projects downwardly from the frame onto the loin
close
to the scribing line so as to determine the thickness of the loin.
In the preferred embodiments shown in Figures 2 to 6, the L-shaped
blade 9 extends upstream of the arcuate blade 7 in order to cut the loin close
to
where it has been scribed, before the arcuate blade 7 engages the loin and
complete full cutting of the same. It is worth noting however that the blades
7 and 9
could alternatively extend both in a same plane transversal to the conveying
system,
if such is desired.
As shown in Figure 6, the arcuate blade 7 that extends behind the L-
shaped blade 9 may have two opposite ends 13, 15 that are both
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connected to the frame. In this particular embodiment, the arcuate blade 7
must of course be shaped so as to engage the loin and cut the backfat to be
trimmed thereof from the side of the loin that is opposite the belly up to the
scribing line.
Alternatively, as shown in Figures 2 to 5, the arcuate blade 7 that
extends behind the L-shaped blade 9 may have only one of its ends 13
connected to the frame and the other end 15 that remains free and extends
close to the L-shaped blade 7. In such a case, the two blades 7 and 9 can be
completely separate from each other as shown in Figure 5 or alternatively
1o and preferably, they can be connected to each other :
either by means of a ring 10 to form a slide, as is shown in Figure 2 ;
or by means of a joint of conventional structure, like a string or a
swivel;
or even more preferably, by means of a pivot 11 that projects
rearwardly from the L-shaped blade 9, and in which is pivotably
inserted the end of the arcuate blade, as is shown in Figures 3 and 4.
Such a connection of the free end of the arcuate blade 7 to the L-
shaped blade 9, is particularly interesting in that it makes it possible for
the
arcuate blade 7 to be made of a flexible material and be operatively
connected to the L-shaped blade 9 that is then made of a rigid material. In
this particular embodiment, respective adjustments of the arcuate blade and
of the L-shaped blade by their own control systems permit to modify the
arcuate shape of the arcuate blade and thus to adapt its cutting to the loin
to
be trimmed off. Such is illustrated in Figures 7a to 7f, which show the
particular portions of both blades and the curvature of the arcuate blade 7 as
a function of the positions of their control systems 23, 25. In these figures,
some of the arrows show the motions given to both of the control systems,
up, down or stationary (=). Other arrows show the way the arcuate blade 7 is
flexed as a function of the motions of the control systems.
As may thus be noticed, the improved loin puller according to the
invention permits to process loins of any size and/or fatness with a maximum
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efficiency to properly separate the backfat thereof whatever be the thickness
of such a backfat, while substantially reducing the risk of the scoring
portions
of the loin without separating the backfat from the belly.
As is better shown in Figure 3, the L-shaped blade 9 preferably
has a vertical portion with a front cutting edge 17 that extends at an angle
downwardly rearwardly, and a horizontal portion with a front cutting edge 19
of triangular shape that extends frontwardly towards the loin that is moved by
the conveying system.
Advantageously, the cutting edges 17, 19 of the L-shaped blade 9
lo may be sharpened more on one side instead of being sharpened evenly on
both sides like any conventional knife or blade. This "double" arrangement in
the shape and sharpening of the cutting edges 17, 19 of the cutting blade 9
permits to engage the loin close to the ribs "R" in a more efficient way while
substantially reducing the risk of hitting the ribs or any part of the
shoulder
blade that would still be in the piece of meat. Indeed, as soon as the first
rib
"R" is lifted up by the cutting edges of the cutting blade 9 that is sharpened
more on one side, the other ribs which are connected to the first one and to
each other by pieces of meat will also be lifted up in a smooth manner,
thereby reducing the risk of breaking and tearing.
Preferably also, the arcuate blade 7 may have a front groove in
which is detachably inserted a foldable piece of metal 21 having a front
sharpened cutting edge, as shown in Figure 5. Such makes the maintenance
of the loin puller much easier to assume as one may easily replace the
foldable piece of metal 21 of the blade 7 by another new one.
Tests have been carried out by the Applicant on an improved
loin puller as shown in Figures 3 and 4, wherein the arcuate blade 7 was
flexible and had a free end pivotably connected to a pin 11 projecting
rearwardly from the L-shaped blade 9. These tests have proved to be
particularly efficient and have clearly demonstrated the advantage of using
two separate cutting blades as disclosed hereinabove, instead of using only
one blade, in terms of efficiency, cost and results.
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With the improved loin puller according to the invention, better
cutting of the loin may easily be achieved. In addition to a better cutting,
other
advantages are also achieved, such as easier installation, replacement and
s maintenance of each blade, especially when each blade has one end only
connected to the frame.
Of course, numerous modifications could be made to the improved
loin puller according to the preferred embodiments of the invention as
disclosed hereinabove without departing from the scope of the invention as
io claimed hereinafter, it being understood that all the other structural
features
of the loin puller as such are conventional and needs not be further
described.
