Method and machine for segregating meat from bone, heavy tissue, and skin

A machine for segregating meat from bone, heavy tissue, and skin and having a material conveying screw mounted for rotation within a perforated conduit serving as a screen through which the meat is extruded as the bone, heavy tissue, and skin are conveyed toward the discharge end of the machine, is provided with a cutter ring with a cutting face against which the bone, heavy tissue, and skin are projected and cut before discharge. The conveying screw is preferably a cutter screw having a spiral flight which bears against the inside of the screen and contacts the margins of the perforations of the screen in a close cutting action as the screw rotates. Feeding cut meat and bone into the machine and operating the machine constitutes the method of the invention.

BACKGROUND OF THE INVENTION 
1. Field 
The invention is in the field of machines for separating meat from bone and 
from so-called "bony" matter which includes connective and other heavy 
tissues, skin, etc. Such machines have become known as "deboning" machines 
and comprise a conveying screw rotating within a tubular conduit that is 
provided with a multiplicity of small holes as a screen through which the 
relatively soft meat component is extruded under pressure as the bone and 
bony matter is advanced to a discharge outlet that is usually provided 
with a restrictive ring valve arrangement for effecting and controlling 
back-pressure within the machine. 
2. State of the Art 
Deboning machines have evolved through the years from that disclosed by 
McFarland U.S. Pat. No. 3,739,994 issued Jun. 19, 1973 (reissued Jul. 17, 
1984 under Re. U.S. Pat. No. 31,631), which was the first to provide for 
the building up of a filter mat along the inside surface of a perforate 
tubular conduit as a screen through which the meat must pass before being 
expelled as filtered largely free of bone particles. The desired filter 
mat was created by leaving a small clearance between the outer edge 
surface of the spiral flights of an auger feed screw and the inner surface 
of the screen. The bone and bony matter was passed through an adjustably 
restrictive, annular orifice formed between the inside surface of a ring 
movable longitudinally relative to an extension of the auger screw and 
leading to a discharge outlet for the bone and bony matter. An additional 
feature was the provision, in an alternative embodiment of the machine, of 
a pair of knife blades freely inset into receiving notches in and along 
the flights of the auger screw, with sharp edges of such blades bearing 
lightly against the inner wall of the screen so as to cut fibers that 
create drag, but without destroying the filter mat. 
U.S. Pat. No. 4,189,104 of Feb. 19, 1980 to Claudio dos Santos discloses an 
improved machine, wherein the face of the ring valve confronting the 
advancing bone and bony material being passed to and through the 
restrictive annular orifice is scalloped to cooperate with a 
correspondingly scalloped end portion of the auger screw extension in 
effecting a more rapid passage of material through the machine to increase 
output per unit time. 
McFarland U.S. Pat. No. 4,566,640 of Jan. 28, 1986 speaks of grooves and 
vanes (the lands between the grooves) on an extension of the auger screw 
for grinding or chopping disjointed neck or spinal bones into sufficiently 
small particles to pass through the restricted annular orifice between the 
stationary ring and the extension portion of the rotating auger screw. 
Machines of a type that have been made to operate on relatively large, 
unground pieces of meat and bone have suffered by low throughput and 
failure to cope with the larger pieces of bones, heavy tissues, and skin. 
SUMMARY OF THE INVENTION 
I have now improved machines of the type concerned to greatly increase 
throughput and thereby greatly increase output of the desired meat 
product, particularly where fairly large pieces of unground and 
refrigerated or frozen meat and bone are being fed thereinto. 
It should be realized that government agencies controlling the sale of food 
products have various arbitrary definitions for terms such as meat, flesh, 
poultry, etc., which govern the amount of bone, heavy tissue, skin, and 
the like that may be included in a final product offered for sale. 
Therefore, limiting the content of such extraneous matter in a final 
product is becoming more and more important. 
Accordingly, besides increasing throughput, a primary objective of the 
invention is to enable more effective control of the separation procedure 
and discharge of relatively large pieces of bone, heavy tissue, and skin 
by paying attention to structural details that heretofore have not been 
regarded as important. 
From the standpoints of both increased throughput and coping with 
relatively large pieces of bone, connective tissue, and skin, I have made 
the adjustable, back-pressure, choke ring of prior machines into a cutter 
ring by providing cutting means on the cutting face thereof that confronts 
the outflowing mass of bone, heavy tissue, and skin traveling toward the 
discharge outlet of the machine. From the standpoint of control in a 
machine utilizing this concept of a cutter ring, blade members on the 
annular cutting face confronting a usually narrower annular face on the 
discharge end portion of a conveying screw or on an extension thereof, 
which confronting faces define between them a restrictive annular orifice 
as in earlier machines, the cutting means are preferably a series of 
mutually spaced and elongate cutter elements inset into and preferably 
progressively protruding from the cutting face of the ring along their 
lengths. Moreover, for best results, the cutting elements are disposed at 
an acute angle to the radial. 
Preferably also, the creation of a filter mat has purposely been avoided by 
making the flights of the feed screw sharp, as a continuous spiral blade, 
and bearing closely against the inside surface of the screen to effect a 
strong cutting action relative to the perforations thereof along the 
length of such screen, thereby avoiding the creation of a filter mat. 
From a method standpoint, throughput of material along a machine of the 
type concerned is enhanced by passing the stream of separated bone, heavy 
tissue, and any skin that may be present into the face of a cutter ring 
equipped with sharp cutter elements arranged for cutting action on such 
bone and heavy tissue as they travel toward the discharge outlet therefor. 
At the same time, pieces of heavy tissue or skin that become stuck in the 
tiny holes of the screen and drag as the material travels along the axis 
of the machine are cut free by the cutter feed screw, rather than 
remaining as part of a filter mat, and are therefore carried on toward and 
through the cutter ring and the discharge outlet of the machine. 
In some instances, it may be desirable to provide for rotating the normally 
stationary cutter ring so as to effect a combined action with the rotating 
cutter screw and extension thereof, whether or not such cutter screw or 
extension is also provided with cutting means.

DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENT 
In the form illustrated, the machine of the invention comprises a conveying 
screw or auger formed as a cutter screw 10 having a spiral flight 10a and 
extending through and adapted to rotate within a perforate tubular conduit 
or screen 11 while conveying pieces of meat and bone and other relatively 
heavy tissue, such as tendons and gristle, and skin, along the interior of 
screen 11 from a feed end of such screw (not shown), receiving the 
material to be treated, to a discharge end portion 10b thereof and through 
a final outlet opening 10-1 surrounding an end extension 10c of such 
cutter screw after end portion 10b passes through a cutter ring 12 and, as 
here shown, a restrictive annular orifice 13, FIG. 2, for the bones and 
heavy tissue that do not pass through the tiny perforations 11a of the 
screen along with the meat. Such end extension 10c of screw 10 connects 
with rotating means (not shown) beyond final outlet opening 10-1. 
As is typical of choke rings of machines of the type concerned, cutter ring 
12 is elongate, externally threaded, as at 12a, and rotatable within an 
internally threaded housing member 14 for back and forth, longitudinal, 
position-adjusting movement relative to such housing member 14 and to the 
discharge end portion 10b of cutter screw 10 and the end extension 10c 
thereof. A spring-activated pawl 15, mounted within a housing member 16 
and engaging a ratchet wheel portion 12b of cutting ring 12, provides for 
manually turning of ring 12 in the appropriate direction for screwing such 
ring forwardly or backwardly so that the cutting face 12c thereof is in a 
desired adjusted position relative to the discharge end portion 10b of the 
cutter screw and, preferably, as shown, relative to a confronting annular 
face 10d, FIG. 2, thereof. 
The annular cutting end of cutter ring 12 is concave as is customary for 
choke rings of prior machines, placing cutting face 12c at an acute angle 
to the longitudinal axis of the machine and sloping inwardly. 
In accordance with the invention, cutting face 12c of cutter ring 12 is 
provided with cutting means, which, as here shown, comprises a series of 
mutually spaced blades 17, each extending across such annular cutting face 
at a slope, from the inner to the outer circumference thereof in the 
direction of rotation of the feed screw, of preferably about forty-five 
degrees from the radial, see the angle 17a, FIG. 5, between the blade 17 
and the radius indicated by the applied light line. 
The blades 17, as shown, are preferably square or otherwise rectangular in 
cross-section and inset into and secured within corresponding receiving 
grooves 18 formed in cutting face 12c, such grooves advantageously each 
progressively lessening in depth from the inner circumference of such 
cutting face to the outer circumference thereof, so that the distances of 
exposed cutting edges 17b of the respective blades above the respective 
lands 19 between adjacent blades progressively increase correspondingly 
from such inner circumference to such outer circumference providing relief 
spaces 17c between such blades. However, the blade edges could be 
completely above the cutting face, and any increase in distance above the 
cutting face need not be progressive along the length of the blade 
element. The blades should be of tungsten carbide or similar extra hard 
and durable cutting material. 
As shown, the forward end of cutter ring 12 engages an annular seat 10e, 
typically from about one-sixteenth to one-eighth of an inch in width 
formed about the discharge end portion 10b of the cutter screw, with the 
cutting face of ring 12 confronting face 10d of the cutter screw. Seat 10e 
may be provided, as shown in FIG. 2, with divergent recesses 10f for 
passage of matter therethrough despite choke action of the cutter ring and 
advantageously slopes outwardly in the direction of material travel so 
that restrictive orifice 13 progressively increases in size as cutter ring 
12 is moved in that direction. It is also advantageous that confronting 
face 10d of the cutter screw slope less steeply than does cutting face 
12c, see FIG. 2, so that annular orifice 13 provides relief space between 
such confronting faces. 
I have found that, for most effective meat output, the flight pitch 
(distance between consecutive flight turns) for the cutter screw should be 
at least approximately four inches. The cutter screw can taper from feed 
end to discharge end as shown, but need not. 
It is advantageous to also provide material-forwarding recesses 21 as a 
circular series thereof in the discharge end portion 10b of the cutter 
screw, and to provide at least one opening 22 through the annular wall of 
the cutter ring intersecting the interengaging threads between cutter ring 
12 and housing member 14 to pass, internally of the cutter ring, any 
matter caught between the threads. 
For most effective cutting action with respect to the perforations of 
screen 11, the normally rounded, spiral, outer ends of flight 10a of 
cutter screw 10 should be flattened somewhat and provided with a cutting 
edge 10f facing the direction of material travel within and along the 
screen. Such cutter screw bears closely against the inside surface of the 
screen for cutting contact with the margins of the perforations thereof as 
it rotates. 
Constructed as shown, a machine of the invention operating on an input of 
22,000 pounds of unground poultry will produce from about 16,000 to 17,000 
pounds of useable meat per hour. This means that unground mixtures of many 
types of meat with bone can be effectively and economically handled by the 
machine of the invention. 
Whereas this invention is here illustrated and described with reference to 
embodiments thereof presently contemplated as the best mode of carrying 
out such invention in actual practice, it is to be understood that various 
changes may be made in adapting the invention to different embodiments 
without departing from the broader inventive concepts disclosed herein and 
comprehended by the claims that follow.