In defleshing of an animal hide, the hide is tensioned inside out on a substantially conical defleshing drum actuated into a slow-motion rotation. A rapidly rotating cutter is adapted to meet the animal hide in such a position that its axis of rotation is situated in a plane perpendicular to the longitudinal axis of the defleshing drum, preferably in a vertical position. The cutter is driven in a slow motion on the defleshing drum from the nose end to the tail end of the animal hide so as to perform the defleshing operation along a helical line. The rotation of the defleshing drum and the drive speed of the cutter are synchronized with each other so that the forward motion of the cutter during one revolution of the defleshing drum corresponds to the width of the area defleshed by the cutter at the same time, whereby the entire hide will become defleshed as the cutter reaches the tail end of the hide.

In conventional cutter heads designed to rotate in one direction only, a problem arises in the defleshing of the hide behind the ears and front feet when these parts cover a portion of the hide. This defleshing frequently causes undesirable winding of the hide about the defleshing drum thus causing locally incomplete defleshing or in the worst case, damage to the hide itself. This is because previously known cutters according to the preamble are provided with cutting inserts mounted fully rigidly in the cutter head grooves and having a cutting edge that provides an effective defleshing effect only in one direction of rotation.

The above problem can be overcome by virtue of a cutter construction offering a sufficiently effective defleshing effect also when driven in a reverse direction of rotation thus allowing the flesh still adhering to the hide under the front-feet and ear portions thereof during back running of the defleshing machine, whereby also the

rotating direction of the defleshing cutter is reversed.

In the art are known defleshing cutters of the above-described type having a pair of cutting inserts mounted in a reversed position. Thus this pair of cutting inserts performs a certain degree of defleshing when the cutter is driven reverse to its normal rotating direction. A shortcoming of such a cutter is that notwithstanding the selected rotating direction, anyhow those cutting inserts that are at any time oriented in the"wrong"direction will contribute negatively to the defleshing effect.

It is an object of the present invention to overcome all of the above-mentioned problems and to provide a defleshing cutter with perfect defleshing performance irrespective of the selected rotating direction. This goal is attained by virtue of a defleshing cutter characterized in that the cutting inserts and mounting grooves of the cutter are shaped so as to allow a limited inclination of each cutting insert about the longitudinal axis of said insert, while the distal end of the cutting insert is provided with two cutting edges running longitudinally along both edges of the distal end of the cutting insert. In this fashion, an optimized shaping of the insert and its mounting groove render at all times a desired cutting angle and inclination angle of the inserts irrespective of their rotating direction.

According to a first embodiment of the invention, the longitudinal mounting grooves on the periphery of the cutter head have a substantially keyhole-shaped cross section, whose inner portion is circularly rounded while its radially distal portion opening at the cutter head periphery is shaped slightly flaring with a width larger than the corre- sponding thickness of the cutting insert in this portion. The insert mounted in the groove, respectively, comprises an inner stem part having a circular cross section adapted to fit into the circularly rounded inner portion of the groove, and a distal tip part extending radially outwardly from the insert stem and having a thickness smaller than the width of the flaring slot portion of the mounting groove and is provided at its freely projecting distal end with two cutting edges running longitudinally along the insert tip. The insert tip part may have a constant width or, alternatively, be slightly flaring, however, with a flaring angle narrower than the flaring angle of the

distal portion of the mounting groove. The circularly rounded inner portion of the mounting groove and the periphery of the insert stem form with each other such gliding surfaces that allow the insert to pivot around its longitudinal axis, whereby the walls of the flaring slot portion of the mounting groove serve as back stop surfaces for the tip of the insert thus determining the limit angles of insert inclination in either direction.

According to a second embodiment of the invention, the cross section of the mount- ing groove comprises a rounded main portion with circularly segmental walls, which main portion is recessed inwardly toward the cutter head center axis under a slot made to the cutter head periphery and has thereunder, still more inwardly radially situated under its circular shape, a key slot of a given width. The cross section of the key slot may be either rectangular or have the shape of an annular sector. A cutting insert designed insertable into this kind of mounting groove has a stem part of circ- ular cross section that in cooperation with the main portion of the mounting groove forms a sliding bearing supporting the inclination of the cutting insert around its longitudinal axis. From the insert stem part extends radially outward a distal tip part of a slightly smaller thickness than the width of the slot that opens on the periphery of the lamellar cutter head and thus allows the distal tip of the cutting insert to extend outward from the groove, whereby the two longitudinally running edges in the distal end of the insert serve as the two cutting edges of the insert. From the insert stem part, in opposite direction relative to the tip part, further a key portion projects radially inwardly, said key portion being adapted to cooperate with the key slot of the cutter head groove so as to limit the inclination angle of the cutting insert around its longitudinal axis in the mounting groove, whereby the width of the cutter head key slot and the insert key, respectively, are selected such that a desired cutting angle and inclination angle of the insert are obtained irrespective of the rotating direction of the defleshing cutter.

Having the cutting inserts shaped in the above-described fashion, each one of the inserts having two cutting edges of which the leading edge in regard to the rotating direction of the cutter is at all times the one actively performing defleshing. Accord-

ing to a preferred embodiment of the invention, the distal end of the radially out- wardly projecting portion of the insert has a concave cross section resulting in sharper cutting edges, particularly if the insert tip cross section additionally is made outwardly flaring toward the distally projecting insert tip.

The maximum allowable inclination of an insert about its longitudinal axis from its radially neutral position depends on the design of the insert tip, and particularly on the design of its cutting edges. Preferably, the insert inclination angle is in the range of 10° to 15°.

According to a preferred embodiment of the invention, the defleshing cutter head comprises a cylindrical, central clamping headstock member with a rigid flange at its one end plus a plurality of identical lamellar cutter members adapted rotatable on the cylindrical headstock center member and having above-described mounting grooves made on their periphery for accommodating the cutter inserts and the rigid flange as well as the lamellar cutter members are provided with mutually interacting elements that allow a given degree of mutual angular displacement between the adjacent lamellar members of the defleshing cutter head as well as between the rigid flange and the closest lamellar member abutting the same. The mutual angular displacement between the abutting lamellar members makes it possible during the rotation of the defleshing cutter against the animal hide to shift each cutting insert angularly so that a helical alignment of the cutting inserts along the cutter periphery results. As a result, the rotation of the cutter in a given direction causes each cutting insert sequentially counted from the rigid flange to become angularly displaced in regard to each other in the reverse direction to the rotation by the differential angle permitted by the limited mutual angular displacement facility provided between each two abutting lamellar cutter members. When the cutter rotation is reversed, the cutting inserts will in a similar fashion become angularly shifted in the opposite direction into new positions along the cutter periphery such that their helical alignment assumes the same lamellar member-to-member differential angles as those of the first helical alignment but now with a reversed handedness of the helical alignment. This mutual alignment arrangement of the cutting inserts serves to prevent the defleshed

tissue from splashing around during defleshing, particularly as the cutter is arranged to be driven about a substantially vertically aligned axis of rotation having the rigid flange situated upmost. In this position of the cutter, the helical alignment of the cutting inserts force the defleshed tissue to be ejected downward so that the removed tissue can be readily collected into a container included in the defleshing machine construction.

The mutually cooperating elements permitting a certain mutual angular displacement between any two abutting lamellar cutter members, as well as between the rigid flange and the lamellar cutter member closest adjacent thereto, comprise in the first embodiment of the invention at least one guide pin projecting in the axial direction from each one of the lamellar cutter members and, respectively, at least one guide hole made in the rigid flange and each one of the lamellar cutter members at the same radial distance from the central axis of the cutter head as the respective guide pins are located, whereby the guide hole has a diameter larger than the outer diameter of the guide pin and the guide pins have a length so short as to extend only into the hole made in the rigid flange or the closest adjacent abutting lamellar cutter member as seen in the diection of the rigid flange. The diffrence between the diameters of the guide pin and the respective guide hole drilled in the lamellar cutter member allows a certain lamellar member during the rotation thereof in a given direction to rotate in the opposite direction by a differential angle in regard to the closest adjacent abutting lamellar cutter member as compared with the angular position of the rigid flange, whereby the differential angle of the mutual rotation between the members is determined by the difference between the diameters of the guide hole and pin.

Obviously, the outcome of this arrangement is that the farther a given lamellar cutter member is situated from the rigid flange the greater is the angular shift of the given lamellar member from its neutral position, whereupon each one of the cutting inserts of the defleshing cutter assume a helically aligned disposition along the defleshing cutter periphery, whereby the tangential angle of the cutting insert helix in regard to the axial direction of the cutter is determined by the above-described difference of guide hole-to-pin diameter. When the cutter rotation is reversed, the cutting inserts will become angularly shifted in the opposite direction assuming new positions along

the cutter periphery such that their helical alignment assumes the same lamellar member-to-member differential angles as those of the first helical alignment but now with a reversed handedness of the helical alignment. The mutual tangential dis- placement between any two adjacently abutting lamellar cutter members can be, e. g., 1 to 2 mm as measured between the cutting inserts along the cutter periphery.

According to a second preferred embodiment of the invention, the mutually cooper- ating elements that limit the mutual angular rotation between the lamellar cutter members on the cylindrical center member of the cutter headstock supporting the lamellar cutter members comprise a key, which rigidly extends longitudinally on the cylindrical center member over the entire length thereof and has a width linearly flaring toward the rigid flange of the cutter headstock, whereby the key is adapted to cooperate with a key slot made on each one of the lamellar cutter members and having a width slightly wider than the maximum width of the cutter headstock key.

Then, the difference between the lamellar member key slot and the headstock key at each lamellar member determines the maximum possible angular displacement of a given lamellar member about its neutral position. Alternatively, the key of the central headstock of the cutter can have a constant width, while the lamellar cutter members are machined to have key slots of different widths, whereby the lamellar members are stacked so that the lamellar member having the narrowest key slot is placed closest to the rigid flange of the cutter headstock, whereupon the other lamellar members are stacked on the headstock in a successive order of making the key slots to become the larger the farther the individual lamellar member is from the rigid flange of the headstock.

The number of cutting inserts on the cutter periphery is advantageously 4 to 12.

Preferably, the number of inserts is eight. The cutting inserts are angularly displaced at equal distances from each other along the defleshing cutter periphery.

Defleshing cutters of different shapes can be constructed by way of varying the size of the uniform lamellar cutter members. If lamellar members of equal size are used, a substantially cylindrical cutter is formed. In contrast, stacking lamellar cutter

members of linearly decreasing or increasing diameter on the headstock used in the assembly of the cutter results in a conical defleshing cutter and, respectively, the use larger-diameter lamellar members at the ends of the cutter with lamellar elements of a diameter stepwise decreasing toward the cutter middle portion gives an hourglass- shaped cutter having a larger diameter at its ends and a reduced diameter at its middle portion. This arrangement results in a defleshing cutter of maximized effective defleshing width that further is augmented by making the cutting inserts moderately elastic. Hereby the cutting inserts can comply very accurately with the conical shape of the defleshing drum when the cutter moves over the defleshing drum in the defleshing of an animal hide.

Next, the invention will be described in greater detail with reference to the attached drawings wherein FIG. 1 shows a side view of one example of a headstock of a defleshing cutter according to the invention when rotating in a direction indicated by the arrow ; FIG. 2 shows a sectional view of FIG. 1 taken along line A-A and illustrating one cutting insert in more detail; FIG. 3 shows a side view of a second embodiment of the headstock of a defleshing cutter according to the invention; FIG. 4 shows a detail of a second embodiment of the lamellar cutter member and cutting insert for use in a defleshing cutter according to the invention; and FIG. 5 shows a detail of a preferred embodiment of the cooperating elements that limit the mutual angular displacement of the lamellar cutter members about the cylindrical center member of the cutter headstock.

Referring to the drawings, the defleshing cutter according to the invention comprises a central cutter head 1 having a substantially circular or polygonal cross section and

of a plurality of cutting inserts 2 mounted thereon in substantially axially aligned grooves 3 that are angularly displaced at equal distances from each other along the defleshing cutter periphery. In the embodiment shown in FIG. 2, the mounting groove 3 has a substantially keyhole-shaped cross section, whose inner portion 3a is circularly rounded while the radially distal portion 3b opening at the cutter head periphery is shaped slightly outwardly flaring. The insert 2 mounted in the groove 3 is provided with an inner stem part 2a having a circular cross section adapted to fit into the circularly rounded inner portion of the groove 3, and with a distal tip part 2b extending radially outwardly via the flaring slot portion of the groove and having a thickness smaller than the width of the flaring slot portion 3b of the mounting groove. The cutting insert 2 is provided at its freely projecting distal end 2c with two cutting edges 4,5, both of them running longitudinally along the insert tip. This shape of the mounting groove 3 and of the insert 2 allow the insert 2 to rotate around its longitudinal axis from its one limit position shown in FIG. 2, wherein the insert 2 with one lateral surface of its distal tip part 2b abuts the respective wall of the flaring slot portion 3b of the mounting groove, to its other limit position, wherein the other lateral surface of its distal tip part 2b abuts the other wall of the flaring slot portion 3b of the mounting groove 3. The insert 2 assumes the limit position shown in FIG. 2 when the cutter rotates in the direction indicated by arrow C. With a properly selected width of the flaring portion 3b of the mounting groove and a thickness/shape of the insert distal tip part 2b, an equally optimal defleshing effect irrespective of the rotation direction of the cutter is assured. By shaping the free end of insert distal part 2b to have a concave cross section (see hatched shape in FIG. 4) and by shaping the distal end 2b such that its thickness flares toward its free end 2c, an extremely advantageous shape of both cutting edges 4 and 5 of the insert distal tip is received.

In FIG. 4 is shown an alternative embodiment of the longitudinal mounting groove 3 on the periphery of the cutter head 1 with a cutting insert 2 placed in the groove 3. In this embodiment, the cross section of the mounting groove 3 comprises a rounded main portion 3 a with circularly segmental walls, the main portion being recessed inwardly toward the cutter head center axis under a slot 3b of the periphery of cutter head 1. Additionally, the cutter head 1 is provided with a key slot 3c having a given

width and extending still more inwardly radially from the most proximal portion of the above-mentioned rounded mounting groove main portion. Respectively, the cutting insert 2 placed in the mounting groove 3 has a cross section that generally is similar to the cutting insert 2 used in the above-described first embodiment, but differs therefrom by having its stem part 2a complemented with a projection 2d directed in the opposite direction in regard to the distal tip part 2b of the insert. The projection 2d fits into the key slot 3c of mounting groove 3 by way of having a width smaller than the width of the key slot 3c. The difference between the widths of mounting groove key slot 3c and cutting insert projection 2d is employed to set the angle of inclination that the cutting insert 2 can assume as it is inclined about its longitudinal axis in the mounting groove 3. FIG. 4 shows the uppermost cutting insert 2 in the limit position which the cutting insert assumes when the cutter is driven in a counter clock direction, while the other insert is shown in its neutral middle position with the distal tip 2 of the insert oriented entirely radially, from which neutral position the insert can be inclined by about 10° to 15° to either side depending on the rotating direction of the defleshing cutter.

In its simplest embodiment the defleshing cutter comprises an entirely rigid head- stock 1, which in the embodiment shown in FIG. 3 is slightly conical. The cutter head is connected to the drive shaft of the defleshing machine by the uppermost part of the cutter head in the diagram.

According to a preferred embodiment of the invention, the cutter head 1 comprises a cylindrical, central clamping member 6 having a rigid flange 7 adapted at its one end.

On the cylindrical member 6 are rotatingly mounted a plurality of uniform lamellar members 8 incorporating the above-described mounting grooves for accommodating the cutting inserts 2 of the defleshing cutter. The flange 7 and all the lamellar members 8 are provided with a guide hole 9 at a given and same radial distance from the center axis of the cutter head. Additionally, each one of the lamellar members carries an axially projecting guide pin 10 of a diameter smaller than the diameter of the respective guide hole 9, the guide pins 10 being placed at the same radial distance from the center axis of the cutter head as the respective guide holes 9. The guide pins

10 project from the side of their respective lamellar member 8 by a length not exceeding the thickness of the adjacent lamellar member 8. In the assembly of the cutter, the first lamellar member 8 is inserted onto the central clamping cylindrical member 6 of the cutter head so that the guide pin 10 of the lamellar member goes into the guide hole 9 of the flange 7. Thereupon, the next lamellar member 8 is inserted so that the guide pin of this lamellar member 8 goes into the guide hole 9 of the previously inserted lamellar member as shown in the sectional view of FIG. 1. As all the lamellar members 8 are uniform, the mounting grooves 3 on their periphery are initially aligned along axially straight lines on the periphery of the defleshing cutter. In the illustrated situation, the cutter is driven to rotate in the direction indicated by arrow C, whereby as a result each lamellar member 8 becomes angularly shifted in a reverse direction in regard to the next adjacent lamellar member 8 closer to the rigid flange 7 by an angle permitted by the difference between the diameters of guide hole 9 and guide pin 10. As a result, the lamellar members 8 rotate into positions such that the mounting grooves 3 on the periphery of the defleshing cutter align into helical lines as shown in FIG. 1 wherein a complete track of adjacent mounting grooves 3 is shown entirely. Herein, the cutting inserts 2 placed in the mounting grooves 3 respectively align themselves helically into positions wherein defleshing takes place in a fashion preventing the removed tissue from splashing around and instead the tissue is forced downward toward the lower end of the cutter wherefrom the tissue falls down into a container (not shown).

In another preferred embodiment, the guide pins 10 and guide holes 9 of the lamellar members 8 are replaced by a key 10'which rigidly extends longitudinally on the cylindrical center member 6 of the cutter over the entire length of the center member and has a width linearly flaring toward the rigid flange 7, whereby the key 10'is adapted to cooperate with a key slot 9'made on each one of the lamellar cutter members 8 and having a width slightly wider than the maximum width of the cutter headstock key 10'. Then, at each lamellar member 8, the width difference between the lamellar member key slot 9'and the cutter headstock key 10'determines the maximum possible angular displacement of a given lamellar member 8 about its neutral position on the cutter center member 6.