Butchering – Deboning
Reexamination Certificate
1999-12-08
2001-08-21
Little, Willis (Department: 3643)
Butchering
Deboning
C452S165000, C452S169000
Reexamination Certificate
active
06277020
ABSTRACT:
This invention relates to deboning poultry, that is to say, removing white meat from poultry carcasses.
The deboning of poultry, particularly chickens, is done, on a large scale, both manually, by more or less skilled workers, and mechanically. Examples of mechanical deboning systems are to be found in FR 2 593 675, EP 0 695 506 and EP 0 489 984.
A problem with mechanical deboning is that poultry come in different weights and sizes, and a measure of control is needed to accommodate this variability, particularly in regard to the step of cutting ligaments and tendons connecting muscle and bone. Various accommodation techniques have been proposed, including weighing the carcass and imaging the carcass using information so derived to decide where to cut.
JP 6324006 (Snow Brand Milk Products Co. Ltd) proposes for general automatic butchering to use X-rays to determine the positions of muscle, tendon and skeleton.
In WO 97/21352 is proposed a method of removing meat from a poultry carcass comprising determining the relative positions of the carcass and severing means thus causing the severing means to sever tendons by which the meat is attached to the skeleton and further comprising locating automatically at least one datum point on the carcass and automatically moving the severing means and the carcass into engagement in a manner determined by the position of the datum point.
One datum point particularly mentioned in that application is the triosseum canal through which run several important tendons, the cutting of which frees up a large part of the muscle to be stripped cleanly from the skeleton manually or by existing mechanical methods.
The datum point (or points) can be determined by X-ray imaging using machine vision techniques to identify image features. It is preferable to use a three-dimensional image for precise location of the triosseum canal.
Techniques described in WO 97/21351 facilitate rapid location of the triosseum canals for rapid orientation of the cutters and rapid and accurate severing of the tendons, freeing up the meat for clean removal, without damage, as high quality, high value meat with a higher yield than other mechanical techniques and even better than conventional manual deboning.
The present invention, however, further improves upon the methods generally described in WO 97/21351.
The invention comprises a procedure for use in deboning poultry comprising locating the prepared poultry carcass with its wing bones clamped on wing bone rests defining edges which abut the wing bones at their wing joint ends whereby the wing bones are securely held in fixed positions with the carcass depending therefrom, defining cutting axes between the wing bones and triosseum junctions, and cutting on said axes to sever tendons and ligaments.
The cutting axes may be defined automatically by reference to a machine vision image, which may be an X-ray image as described in WO 97/21351 which can be a two-dimensional format or scanning image because of the way the carcass is located. As before, the cutting means may be automatically actuated to cut along the axes defined, and rotary blades could be used.
The wing bone rests may be arranged to hold the wing bones relatively inclined so as to include an angle less than 180° on the side of the carcass, an angle, perhaps, of 90°, though holding them parallel (an inclined angle of zero degrees) is entirely satisfactory.
The wing bone rests may be relatively adjustable to accommodate different carcass sizes, and may be adjusted towards each other after the wings are placed thereon so as to be spaced as closely as the intervening wing joint region of the carcass will allow, the wings being then clamped and, subsequently, the wing bone rests pulled apart to stretch the joints. In this way the tendons and ligaments are available for imaging and cutting by incision between wing bones and triosseum junctions with no fear of displacement under cutting forces.
However, the use of X-rays is problematical in a factory environment and advantage can be taken of the method of locating the carcass to dispense with the need for depth information in regard to certain internal features to be severed or not severed as the case may be by noting that, for a given weight range of carcass, the three dimensional positions of these internal features can be calculated to lie within certain narrow limits. For birds in a 2:1 weight range, distances between identifiable features will vary over a range 2
⅓
:1 or approximately 1.25:1. Using the techniques of the present invention the three dimensional positions of critical internal features can be determined from two dimensional information obtainable from surface features or readily exposed subcutaneous features without the use of X-rays.
Moreover, these procedures greatly facilitate manual deboning, so that while adapted for automatic cutting using machine vision, considerable advantages are gained by using them in manual deboning.
More particularly, the invention comprises a method for removing meat from poultry carcasses to which wings are attached by muscles, ligaments and tendons at wing joints, comprising:
supporting the carcass to depend from its wing joints with the wings clamped to wing bone rests either side of the carcass affording fulcrums for the wing bones;
placing the wing bone rests under separation force to tension the ligaments and tendons at the wing joints;
cutting in a first cut selected muscles, ligaments and tendons permitting the supports further to separate to open out the wing joints whereby to reveal further muscles, ligaments and tendons;
locating such further muscles, ligaments and tendons and cutting in a second cut selected ones thereof; and
completing the removal process by pulling the wings from the carcass and removing freed muscle therefrom.
While rotary blades, as noted above, are suitable, it is now found that greater precision, resulting in less collateral damage to the carcass and consequently improved quality of product as well as improved yield, can be achieved if the first and second cuts are effected using oscillating blade means. While the use of higher frequencies is possible, it is found that frequencies between 1 and 150 Hz are suitable, with an amplitude of oscillation in the range 1-10 mm. The oscillation may be primarily an oscillation lengthwise of a substantially straight blade edge. Such low frequency oscillation reduces or eliminates any occurrence of vibration induced white finger (VWF) as compared to higher frequencies. While regular knives could be used, it is now found that special blades can effect the cuts through muscle, tensioned tendon and ligament without cutting bone—the presence of bone fragments in fillets is highly undesirable. Such blades are between 1 and 2 mm thick at the cutting edge, with edge faces including an angle between 30° and 70°—not classically sharp.
The separation force may be arranged to be, at any stage of the cutting, sufficient to tension any muscle, tendon or ligament to be cut ahead of any other and, such muscle, tendon and/or ligament having been cut, to separate the wingbone rests to open up the wing joints revealing further ligament, tendon and muscle facilitating further cutting. For poultry in the weight range 1.2-2.4 Kg eviscerated weight, the separation force may be between 3 and 4 Kg, typically 3.5 Kg.
Because of the need to tension successively the ligaments and tendons prior to their being severed, it is advantageous to carry out two separate cutting operations (using plane blades)
a first cut to sever the L
1
and T
1
and the propatagium
a second cut to sever T
2
, L
2
and the deltoidus major
Both of these cuts may be either manual or by automatic means.
Two other cutting operations, a cut adjacent to the wishbone to part it from the Pectoralis thoracicus and a cut to part the Scapulohumeralis from the scapula may either be carried out manually or, by using more complex blades, may be effected as part of the first and second cuts respectively.
When the first cut is to be effected automatically, it is
Baker & Botts LLP
Filar Limited
Little Willis
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