Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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LOIN PULLER FOR TRIMMING OFF THE FAT FROM
THE LOIN OF A CARCASS-HALF
FIELD OF THE INVENTION
The present invention relates to a machine hereinafter called "loin
puller" for trimming off the fat from the back of a loin, in particular a pork
loin,
without having to completely cut and separate the loin from the central part
of
the carcass-half of the animal.
BACKGROUND OF THE INVENTION
As shown in Fig. 1 of the accompanying drawings, the central part
of the carcass-half of a piece of meat comprises two main parts respectively
called "loin" and "flank". The loin is adjacent to the cut portion of the
spinal
i5 column. The front portion of the loin contains ribs which are called "back
ribs"
after processing. In the rear portion of the loin is located the tender loin.
The
flank which is also called "belly", is the part which is adjacent to the loin
at the
opposite of the spinal column. The ends of the ribs which extend along the
flank
can altogether be separated from the same to form "spare ribs", or they can be
2 0 removed individually. After removal of the ribs, the flank is mainly used
to
prepare bacon. The whole carcass-half is covered by an external layer of fat
which extends under the loin and flank. 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,
2 5 it is important from a practical standpoint to keep a proper amount of fat
with the
flank prior to cutting the same. However, it is important to remove same of
the
fat extending under the loin to avoid an over load of fat in the final
product.
For trimming the fat off the loin, use is made of automatized
machines called "loin pullers", which are used in the cutting sections of the
3 0 industrial slaughter houses.
Prior to processing a loin in a loin puller, it is of course necessary to
separate it from the flank. So far, there have been two different methods of
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doing so.
The first method, called "Canadian cut", consists in completely
separating the flank 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 pulley or within the same. Once separated, the flank 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
1o is introduced into the loin pulley, in order to trim off its fat.
A non-limitative example of loin pulley specially adapted for
processing loins after full separation from the adjacent flanks is disclosed
in U.S.
patent No. 5,090,939 issued on February 25, 1992 in the name of the Applicant.
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 flank. Then, both of them may be transferred
together
to a working table where the loin is processed to remove part of the layer of
fat
2 0 from the loin. 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 flank, 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,
eventhough industrial machines have been proposed to do it.
Thus, for example, U.S. patent No. 5,295,898 issued on March 2"d,
1994 in the name of ACRALOC CORP., discloses a loin pulley especially
adapted for processing carcass-halves having been subjected to an American
cut. In this loin pulley, each carcass-half is moved by two conveyors
extending
in parallel relationship towards a cutting zone where an arcuate blade which
is
3 o preferably heated and whose height and curvature are adjustable, is
positioned
above the first conveyor supporting the loin for processing the same and
trimming off its layer of fat. While the fat of the loin is cut, the flank is
moved at
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the same speed along the second conveyor, which is positioned at the same
level as the one of the first conveyor and may include another cutting zone
where another knife cut the extra fat extending under the flank (see Fig. 3c
of
this patent).
In the loin pullet disclosed in U.S. patent No. 5,295,898 as well as in
all the other existing loin pullets used for processing carcass-halves having
been subjected to an American cut, the loin and flank are maintained
altogether
in a same horizontal plane. Therefore, an operator provided with manual
control
means must very carefully follow the movement of the carcass-half to determine
1 o the optimum scribing line and to adjust accordingly the scribing saw while
simultaneously adjusting the height of the cutting blade. Such requires much
dexterity from the operator who must determine the scribing line and who has
very few visual information to evaluate the thickness of the layer of fat and
thus
to adjust the height of the cutting blade. Indeed, the operator has no visual
i5 access to the layer of fat under the loin after the loin has been engaged
by the
cutting blade. The operator has also poor visual access to evaluate the
position
of the cutting blade relative to the ribs, because of the presence of the
flank in
horizontal position adjacent to the loin. As a result, the operating speed of
the
machine is reduced as compared to the loin pullets used for processing loins
2 0 having been subjected to a Canadian cut.
A main object of the present invention is to solve the above
mentioned problem by providing a loin pullet which, thanks to its structure,
permits to process carcass-halves having been subjected to an American cut
in view of trimming the fat off the loin while simultaneously permitting to
the
2 5 operator or to a detection system to determine laterally the thickness of
the back
ribs on the loin and the thickness of the meat, and thus to evaluate the upper
level of the layer of fat under the loin, such allowing an evaluation of the
optimum height for positioning the arcuate blade for trimming off the fat with
or
without the adjacent lean meat depending on the user's requirement.
3 o The invention is based on the discovery that, after scribing, by letting
the flank fold down and hang on one side of the loin while said loin is moved
by
the conveyor towards the cutting zone instead of supporting the flank by means
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of another conveyor, it becomes possible for the operator or the detection
system used for controlling the blade, to determine the level of the layer of
fat
under the loin and/or the thickness of the ribs and/or the position of the
lean
meat along the same, such allowing optimum adjustment of the position of the
cutting blade.
Therefore, the present invention provides a loin pulley for processing
a carcass-half comprising a loin and a flank partially separated by scribing,
said
loin comprising a layer of fat of a given thickness to be trimmed off and lean
meat adjacent said layer of fat. This loin pulley is of the type comprising:
- a frame;
- an elongated rectilinear working surface fixed to the frame and
intended to receive and support the loin of the carcass-half to be processed;
- a conveying system mounted onto the frame above the working
surface for engaging the loin, pressing said loin and moving said loin
together
with the flank connected thereto towards a cutting zone; and
-an arcuate cutting blade mounted to the frame in the cutting zone for
engaging the loin when the same is moved by the conveying system and cutting
the layer of fat to be trimmed off the same, with or without lean meat on the
trimmed fat attached to the flank.
2 0 In accordance with the invention, this loin pulley is improved as
compared to the existing loin pulley in that its frame is devised to let the
flank
fold down and hang from the working surface while the carcass-half is moved
by the conveying system, whereby more visibility is left for an operator to
evaluate an optimum cutting position for the cutting blade and more spacing is
left between the cut ribs once the flank is folded down from the loin, thereby
making the loin pulley operable manually or automaticaly from any side and
position along the frame.
This invention is quite simple and very efficient, as tests carried out
by the Applicant have shown it. The invention is also interesting in that it
can be
3 0 carried out by properly adapting the structure of existing loin pulleys,
like the one
disclosed in U.S. patent No. 5,090,939 mentioned hereinabove, in the name of
the Applicant.
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Of course, the frame of the loin puller must be devised to allow the
flank to fold down and move together with the loin to which it is attached.
Advantageously, guides in the form of plates and/or rigid tubes of
metal can be provided at the inlet and along the machines to force the flank
to
5 fold down and hang relative to the loin. Such may be necessary when the
carcass-half to be processed is very cold and rigidified by cooling or for
other
reasons.
BRIEF DESCRIPTION OF THE DRAWINGS
1o The invention will be better understood upon reading the following
non-restrictive description of the preferred embodiment thereof, made with
reference to the accompanying drawings in which:
Fig. 1 is a perspective view of a carcass-half showing the main parts
of it, to which reference has been made hereinabove;
Fig. 2 is a side elevational view of a loin puller for trimming off the fat
with or without the lean meat from the loin of a carcass-half according to a
preferred embodiment of the invention;
Fig. 3 is a front view of the inlet of the loin pulley shown in Fig. 2;
Fig. 4 is a side elevational view of the portion of the loin pulley shown
2 0 in Fig. 2, where is located the rigid guiding plate and the pivotable
plate
positioned downstream the rigid plate for giving a knock to the flank and
folding
it;
Figs. 5a and 5b are perspective views showing in detail the operation
of the pivotable plate used for giving a knock to the flank and folding it;
2 5 Fig. 6 is a rear view of the outlet of the loin pulley shown in Fig. 2,
said figure showing the cutting blade in engaged cutting position in the loin
of
a carcass-half;
Fig. 7 is a perspective view of the cutting blade of the loin pulley
shown in Fig. 2; and
3 0 Fig. 8 is a perspective view similar to the one of Fig. 1, showing a
carcass-half after the loin has been cut.
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DETAILED DESCRIPTION OF THE INVENTION
The loin puller according to the preferred embodiment of the
invention as shown in Figs. 2 to 6 comprises a frame 3 to which is fixed an
elongated rectilinear working surface 5 preferably having a concave cross-
section. An endless belt 6 is mounted onto the working surface 5 for
facilitating
the conveying of the carcass-halves along the working surface. As shown in
Figs. 3 and 6, several retractable rollers 21 held in lower position by means
of
return springs or cylinders are fixed to the frame above the belt for applying
a
pressure onto the same and thus maintaining the belt in contact with the
working
1o surface before and after passage of each carcass-half. The working surface
5
is intended to receive and support the loin "L" of a carcass-half to be
processed,
with the layer of fat "G" in downwards position.
A conveying system comprising two endless chains 7 each provided
with teeth 9, is mounted onto the frame above the working surface for engaging
the loin L, pressing on the same and moving it together with the flank F
connected thereto toward a cutting zone located downstream, where an arcuate
cutting blade 11 whose height and curvature are adjustable, is positioned to
engage the loin while the same is moving and to cut the layer of fat G to be
trimmed from the same. This conveying system and its operation in synchronism
2 o with the belt 6 mounted onto the working surface 5 are well known in the
art. In
this connection, reference can be made to the content of the disclosure of
U.S.
patent No. 5,090,939 and to all the other patents that were cited during its
examination. The method used for cutting the layer of fat by means of an
arcuate cutting blade 11 is also well known in this field. In this connection,
it is
2 5 worth reminding that such a cutting can be made manually via means
controlled
by an operator for adjusting the cutting blade as a function of the evaluation
of
the thickness of the layer of fat to be trimmed of the loin. Alternatively,
such
method can be carried out automatically by the combination of a detection
system with means controlled by said detection system for adjusting the
cutting
3 0 blade as a function of the evaluation of the main parameters from trimming
off
the loin. Once again, reference can be made to the description of U.S. patent
No. 5,090,939.
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As previously indicated, the present invention lies in that the loin
pulley 1 and more specifically its frame 3, are devised to let the flank fold
down
and hang from the working surface 5 while the carcass-half is moved by the
conveying system. For this purpose, the frame 3 is provided with supporting
arches 13 leaving a lateral free space adjacent one side of the working
surface
5 (see Fig. 3). The flank which hangs down with respect to the loin L as
clearly
shown in Fig. 6, provides better lateral visibility and thus permits to the
operator
or to the detection system to better determine laterally the thickness of the
back
ribs on the loin and the thickness of the meat, and thus to evaluate the upper
level of the layer of fat under the loin, such allowing an evaluation of the
optimum height for positioning the arcuate blade for trimming off the fat with
or
without leaving, by choice, lean meat on the trimmed fat still attached to the
flank (see Fig. 8). Moreover, the flank, once it is folded down, leaves enough
space between the back ribs and spare ribs to make it possible for the loin
pulley
to be operated manually or automatically from any side and position along the
frame.
For facilitating the operation of the loin pulley, and more particularly
the introduction and exit of the carcass-halves, an inlet conveyor 23
comprising
an endless chain 25 provided with teeth, is positioned at the inlet of the
loin
2 o pulley 1 for supporting the flank when the carcass enters the loin pulley.
A
guiding rod 27 is also positioned at the inlet of the loin pulley for
facilitating
positioning of the loin on the working surface. An outlet conveyor 29
comprising
an endless chain 31 provided with teeth, is positioned at the outlet of the
loin
pulley for lifting up the flank and supporting the same when the carcass-half
exits
2 5 the loin pulley. As is shown, the guiding rod 27 preferably consists of an
horizontally extending rigid tube connected to the frame by means of a set of
pivoting arms 33 forming a deformable parallelogram in order to be able to
retract in a vertical plane depending on the thickness of the loin. Moreover,
a
guiding plate 35 is mounted in a rigid manner to the frame 3 above the inlet
3 o conveyor 23 upstream the same. As is shown, this guiding plate 35 extends
at
an angle in order to start folding the flank down from the carcass-half while
said
carcass-half is moved by the conveying system.
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Because of the refrigeration of the carcass-halves to be processed
or for any other reason, the flank may sometimes remain in the same plane as
the loin to which it is attached. To force the flank to fold down and hang,
mechanical means 37 may be mounted upstream the cutting knife. These
means 37 are controlled by a detector 38 (see Fig. 4) for giving a knock onto
the
flank of the carcass-half while said carcass-half is moved by the conveying
system. The knock which is so given, forces the flank to fold down and hang.
The mechanical means 37 for giving a knock to the flank are shown in greater
details in Figs. 4, 5a and 5b. They preferably comprise a pivotable plate 39
1 o mounted onto the frame 3 and at least one jack 41 and/or 43 mounted
between
the plate 39 and the frame 3 for moving the plate down and folding it from an
horizontal position (see Figs. 4 and 5a) down to an inclined position (see
Fig.
5b) as soon as a signal is received from the detector 38 (see Fig. 4). In the
illustrated embodiment, the plate 39 is mounted onto a piece 45 which is
itself
slidably mounted onto the frame 3 so as to be movable up and down. The first
jack 41 lowers this piece 45 and the plate 39 pivotably connected thereto when
a signal is received from the detector. The second jack 43 simultaneously
forces
the plate 39 to pivot.
Advantageously, a guide 15 consisting of a rigid tube is fixed to the
2 o frame downstream the pivoting plate. The guide 15 is fixed to the frame
close
to the cutting zone and is devised to engage the flank and hold it in folded
position while the layer of fat is being cut.
As may be appreciated, the structure and operation of the loin puller
1 disclosed hereinabove make the trimming of the layer of fat much easier to
2 5 carry out. As a result, one may obtain product of very high quality at a
much
higher speed. As a matter of fact, this speed can be similar to the one of the
loin
pullers presently used for processing loins having been subjected to Canadian
cut.
It is obvious that numerous modifications could be made to the
3 o preferred embodiment that has just been disclosed hereinabove without
departing from the scope of the invention. For example, to further improve the
efficiency of the loin puller 1, the lateral side 5 of the working surface of
concave
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cross-section on which extends the flank can have a lower height than the
other
opposite side. Moreover, as better shown in Figs. 6 and 7, the arcuate blade
11
can be distorted to define recesses 51 adjacent to the side thereof where is
located the flank "F" of the carcass-half, and means 53 operated by another
detector 55 can be provided for automatically lowering and/or widening the
blade 11 when the blade passes close to the end of the carcass-half where is
located the blade bone and/or the other end where is located the tenderloin.
The
blade 11 can also have a projecting tooth or small blade 57 close to the
recesses 51 to facilitate viewing of the blade travelling through the fat and
to
provide a lifting effect on the ribs.
It is worth noting that the carcass-halves can be fed into the loin
pullet according to the invention with their shoulder side first or with their
ham
side first.
It is worth noting also that the loin pullet according to the invention
may not necessarily be operating in a continuous manner, with the conveying
system moving the carcass-halves at a constant speed. As a matter of fact, the
loin pullet according to the invention could be operating sequentially.
Moreover, some structural component thereof could be operating in
a different manner. Thus, by way of non-restrictive example, the arcuate
cutting
2 0 blade could be moved through the loins to be processed instead of having
said
loins being conveyed to said cutting blade as was disclosed hereinabove.
