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Publication numberUS3772951 A
Publication typeGrant
Publication dateNov 20, 1973
Filing dateApr 12, 1971
Priority dateApr 14, 1970
Also published asDE2046399A1
Publication numberUS 3772951 A, US 3772951A, US-A-3772951, US3772951 A, US3772951A
InventorsRepetto S
Original AssigneeRizzi & Co Spa Luigi
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Skin slicing machine
US 3772951 A
A skin splitting machine having a band blade entrained over spaced pulleys. A pair of sharpening units are mounted one over and the other below a run of the blade. The sharpening units comprise a grinding disc having a frontal planar surface and are mounted so as to be vertically, horizontally and tiltably movable with respect to the edge of the blade.
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Description  (OCR text may contain errors)

United States Patent Repetto Nov. 20, 1973 [5 SKIN SLICING MACHINE 860,530 7/1907 Cormany 83/174 3,395,595 8/1968 Braun et a1. 83/174 [75] Inventor: Sum Repem Mme, Italy 1,199,836 10/1916 Sweet 51 247 73 Assigneez SJLA. Luigi Rizzi & C" Modena, 2,541,615 2/1951 Ruau 51/247 Italy [22] Filed; Ann 12 71 :rimary EaigminlegTDonald R. Schran ttorne urt 6 man 21 Appl. No.: 133,032 y [30] Foreign Application Priority Data [57] ABSTRACT Apr. 14, 1970 Italy "23283 A/70 A Skin Splitting machine having a band blade em trained over spaced pulleys. A pair of sharpening units 83/l;t2,65i1/72;1t; are mounted one over and the other below a run of [58] Fie'ld ll 12 247 the blade. The sharpening units comprise a grinding disc having a frontal planar surface and are mounted 56] References Cited so as to be vertically, horizontally and tiltably movable Orlow 83/174 with respect to the edge of the blade.

7 Claims, 8 Drawing Figures PAIENIEMnveo ms 3.772.951 sum 1 c; 5


The present invention relates to a skin slicing or splitting machine, and in particular to apparatus for sharpening the blade thereof.

Conventional skin splitting machines for forming animal hides or the like are provided with an endless belt type blade held taut between the ends of a pair of spaced pulleys, at least one of which is driven to move the blade longitudinally, thus permitting a new edge to be presented to the skin at all times. The skin itself is conveyed between a pair of rollers, one of which is also driven to move the skin transversely through the blade. Usually the upper conveyor roller is driven and is provided with means for locating it at a predetermined distance from the cutting edge of the blade to obtain the desired thickness of the skin. The blade is furthermore provided with a sharpened cutting edge inclined on both faces to form a cutting angle, the bisector of which is downwardly inclined to produce a thrust in the skin,

as it is being cut, toward the direction of the upper rol- I ler.

It is obvious that maintaining a sharp, exact and perfect cutting edge is essential for accurate and efficient cutting of the skin, particularly when very thin slices are required. The slicing machine is, therefore, generally provided with means for continuously sharpening the blade, comprising a pair of rotating grinding discs aligned on either side or face of the blade. The discs are rotated about their centers and are displaceable relative to the edge of the blade to obtain tangential points of contact of the proper and desired inclination to form the cutting edge.

In conventional devices, it is difficult and often impossible to determine the exact position and location of the grinding discs and consequently the accuracy of the cutting edge formed on the blade. This is particularly so since the position of the relative centers of the two discs is difficult to determine because of the constant variation and wear in the grinding discs themselves.

Another difficulty arises from the fact that conventional devices are manually adjustable and hence depend solely upon the skill of the operator. This presents a problem when it becomes necessary to change the blade position in order to process different skins or to produce different thickness. In conventional'grinding discs the speed of rotation must be varied as the result of their wear in order to maintain a constant peripheral speed with respect to the moving blade.

It is, therefore, an object of the present invention to provide a skin splitting machine having a blade and sharpening arrangement overcoming and eliminating the drawbacks of the prior devices.

It is another object of this invention to provide a skin splitting machine having a blade and sharpening arrangement which may be automatically operated and which may be constantly varied to compensate automatically for wear on the blade or on the sharpening disc.

It is a further object of the invention to provide a skin splitting device having a blade and sharpening arrangement in which a constant cutting angle is automatically maintained over long periods of use. It is yet another object to provide a device of the type described which is of simpler construction and which is more economical to produce, maintain and operate.

According to the present invention, a skin splitting machine having an endless blade is provided with two sharpening units, one locatedabove and the other located below the blade. Each-sharpening unit comprises a cup-shaped grinding disc, the axial edge of which forms a planar frontal cutting surface. Each disc is mounted for rotation about its central axis and is provided with means for inclining or tilting the frontal edge relative to the surface of the cutting edge of the blade. Each disc is also provided with means for vertical and horizontal displacement to define 4 an accurate and exact tangential cutting angle with the edge of the blade, this means being provided with visible indicia indicating and clearly establishing the position of the disc relative to the blade.

Preferably, the apparatus is provided with means for automatically adjusting the vertical, horizontal and tilting positions of the disc with respect to the blade, with or without varying the cutting angle thus formed.

The device is also provided with means for advancing the blade relative to the cutting disc to compensate for wear on the blade and for maintaining a constant uniform pressure on the blade itself.

Various other features and details are disclosed in the following description and in the accompanying drawing wherein FIG. 1 is a schematic front elevational view of a skin splitting machine,

FIG. 2 shows a section of the sharpening device, taken on a horizontal plane along the line IIII of Flg.

FIG. 3 is a vertical section of the device, taken along the line III--III of FIG. 1,

FIG. 4 is a vertical section taken on line IV-IV of FIG. 1,

FIG. 5 is a longitudinal axial section of a grinding disc carrying unit taken on the vertical plane V-V of FIG.

FIG. 6 is a detail of one embodiment of the means controlling the vertical movement of the grinding disc, taken on the line for VI-VI of FIG. 3,

FIG. 7 is a view similar to that of FIG. 6 and showing another embodiment of the control means, and

FIG. 8 is a schematic of the entire machine.

In the drawing, only as much of the machine as is required for understanding the present invention is shown. The skin conveyor rollers are schematically il lustrated, while the drive means, table means, removal or receiving means for the skin or carcass, and various other details well known to those skilled in this art, are not shown. Reference, of course, can be made to the readily available technical and patent literature for those details required.

The machine, generally depicted in the numeral 1, is provided with a pair of pulleys 2 and 3 spaced laterally to either side of an opening which receives the skin or animal carcass. A continuous or endless bond or belt type blade 4 is held taut over the pulleys, and one of the pulleys is driven by a conventional drive means, such as an electric motor directly connected to it by an intermediate gear arrangement. At a suitable point along the lower run of the blade 4, there is mounted a housing 5 containing the sharpening mechanism and its adjustment devices. The sharpening'mechanism comprises two independent units 6 and 7 the first of which is disposed above and the second of which is disposed below the blade.

As seen in FIG. 2, the blade itself is held by a pair of carrying members 8 and 9 which are adapted to be advanced or retracted in the horizontal plane so as to move the edge of the blade toward or away from the sharpening units. This arrangement provides for the compensation of the loss of material caused by wear of the blade itself during use and also provides adjustment for the blade so that it may accommodate different skins or be made to out different thicknesses. The car rier means 8 and 9 are mounted by suitable mechanisms, such as that shown schematically in FIG. 2 and in more detail in FIG. 4, so as to move the blade horizontally. Each of the carriers 8 and 9 is mounted by an intermediate gear control means (seen in FIG. 4) to a shaft 10 connected to a transmission gear box 11 controlled by means ofa drive chain 12. The chain 12 may be connected to a manual drive mechanism or may be automatically operated by conventional control means or by the system shown in H6. 6.

The sharpening units 6 and 7 are identical in construction and are mirror images of each other. Consequently, as shown in the drawing and as described herein, similar parts bear similar reference numerals and a description of one of the units should suffice as a description of the other. As seen in FIGS. 2 through 5, each sharpening unit comprises a fixed base bracket 13 secured to a frame or other supporting member of the machine. A vertically slidable member 14 is dovetailed with the bracket 13 so as to be slidable thereon. In turn, the vertical slide 14 mounts a horizontal slide member 15 which is also dovetailed to it. A cylindrical slidable shaft 16 extends from the horizontal slide 15 and is rotatable about its central axis. This third slide or cylindrical shaft 16 supports a motor 17 and a grinding unit carried in a mandrel sleeve 18. The shaft of the motor 17 is provided with a pulley 19, while within the sleeve 18 there is mounted a rotatable shaft 20 on suitable roller or ball bearings 18a. The lower end of the shaft 20 has a pulley 21 while the upper end of the shaft secures a cupshaped grinding disc 22. The pulleys l9 and 21 are interconnected by a drive belt 23. The motor 17 is preferably an electric motor and is provided with the usual control and operating means (not shown), whereby the belt 23 is caused to drive the grinding disc 22.

The fixed base 13 carries a control mechanism for moving the vertical slide 14, comprising a horizontal worm 24 having a hand wheel 25 at one end and engaging at the other end with a worm wheel 26. The worm wheel 26 is secured within a small body mounted above the bracket 13 and is free to rotate but not to move axially. The worm wheel 26 is threaded about an elongated screw 27 connected by a fixed extension 14a to the slide 14. Rotation of the hand wheel 25 will of course move the vertical slide 14 up and down with respect to the fixed bracket 13.

The horizontal slide 15 is displaced through a rotary shaft 28 to which a hand wheel 29 is also secured. The shaft 28 is threaded and screwed through a correspondingly threaded bore in the slide 15 and is supported on the fixed bracket 13 so that rotation of the wheel 29 will move the slide in a horizontal direction with respect to the fixed bracket 13.

The cylinder 16 is rotatably mounted on the slide 15 by means of an extension sleeve 16a which is dovetailed within the slide 15. The cylinder 16 is held in position by a plurality of bolts 30, the heads of which are movable in an annular groove 31. By loosening the nuts of bolts 30, the cylinder may be rotated in its dovetailed mounting with respect to cylinder 5 about the horizontal axis extending through the center of the cylinder. Both the slide 15 and the cylindrical sleeve 16a are provided with cooperating indicia 32 such as a vernier calibration to make visual the relative rotation and position of the parts. The slides 14 and 15 and the fixed bracket 13 may also have cooperating indicia. However, the screws 24 and 28 are generally in themselves sufficient to define the extent of movement and relationship.

With the structure thus described, the grinding disc may be adjusted relative to the vertical, horizontal and tangential angle of the blade edge. Since the two sharpening units 6 and 7 are identical in construction, the cutting angle formed on the edge of the blade may be defined by the individual tangential angles made by each cutting disc with the blade edge. These angles can be selectively varied to any desired degree so that a desired and predetermined cutting angle can thus be fashioned. Preferably, the cutting angle is such that the thrust created by the blade in the skin turns the skin upwardly toward the upper roller of the skin conveyor.

Returning now to the supporting carrier for the blade 4, as described previously in connection with FIG. 2, reference is made in greater detail to the mechanism seen in FIG. 4. The blade 4 is supported by a guide 33 which is provided with a forward slotted edge to receive it. A suitable low friction blade holder 33a is provided about the rear edge of the blade. A strip 34 of metal or other suitable material is located in the slot of the guide 33 and bears against the rear edge of the holder 33a. Abutting against the strip 34 is a block 35 which has a threaded bore into which a screw 36 is inserted. The screw 36 is provided with a knob 37 at its outer end which has a worm exterior 37a engaging the shaft 10 described in connection with FlG.2. Thus, by manually turning knob 37 or the shaft 10 or by automatically turning the shaft 10 through the transmission 11, the horizontal position of the blades may be adjusted relative to the grinding disc.

Manual operation of the slides 14 and 15 have been described. However, displacement may also be obtained automatically in the manner depicted by the ratchet and pawl system seen in FIG. 6 which, for example, is shown operating the vertical guide 14. This system comprises a ratchet wheel 25a which is connected to the hand wheel 25. An electromagnet 38 having a displaceable core 39 carrying a hinged pawl 40 is provided. The pawl 40 is urged by a spring 41 into engagement with the teeth of the ratchet wheel 25a. A rear stop 42 limits the rear movement of the core 39. By actuating the electromagnet 38, the core 39 is moved rearwardly, carrying the pawl 40 with it so as to rotate the ratchet 25a and hence cause rotationof the screw 24. A similar ratchet and pawl system may be applied to control the shaft 10 or the shaft 28 if desired. The signal or pulse for operating the electromagnet 39 may be programed by computer; or it may be directly responsive to the rollers or other means controlling movement of the hide or operation of the machine.

As seen more clearly in FIG. 5, the grinding disc comprises a cup-shaped member having a cylindrical axial edge 22a provided with abrasive material which forms a planar frontal grinding surface. The cyupshaped disc 22 is generally cylindrical in construction and fits over a supporting member 43 mounted over the shaft 20 of the mandrel unit. Suitable screw fasteners 44 and retainer means 45 are employed to secure the disc squarely on the supporting member 43. The provision of a planar frontal surface along a relatively narrow edge provides an improved grinding surface for the blade even the blade and the grinding surface are both held in substantially shallow or sharp angular positions to each other.

In FIG. 7, an hydraulic actuator 50 is shown as an alternate to the electromagnetic actuator 38 shown in FIG. 6. The mechanical structure of the hydraulic actuator is basically the same as that seen in FIG. 6 and the same reference numerals designate the same parts. The electromagnet, however, is replaced with piston and cylinder unit 51 and 52. The piston 51 is fixed to the shaft 39 securing the pawl 40. The arrangement forms a double acting piston-cylinder and is provided with a pair of inlet/outlet ports 53 and 54 which are connected to a source of hydraulic fluid, a pump and similar conventional structure. Valves interposed in each of the lines 53 and 54 are responsive to a manual or automatically applied signal, such as from a pulse generator or source of current. The valves in the latter case may be solenoid-operated.

FIG. 8 depicts schematically the arrangement of knife 4 in the machine as a whole. For proper splitting operation, the position of the knife is determined by the distance a between a plane passing vertically through its cutting edge and the plane in which the axes of the top and bottom conveyor flywheel rollers T and S respectively lie. The configuration formed by the proper and predetermined distance a of the knife 4 from the wheels T and S tends to move the knife 4 horizontally away from the rollers on pressure of the moving skin. The knife, however, is kept in its defined position by reaction of the pusher members 8 and 9 (FIG. 4). After some operation, the knife edge wears and the distance a becomes enlarged. The pusher 8 and 9 under operation of the lead screw and nut set 36 and 35 (FIG. 4) and by the worn gear l-37a permit repositioning of the knife edge at the predetermined optimum point.

Similarly, during operation the grinding wheels also wear and become displaced. These may also be repositioned by adjustment of the screw mechanism 26-27 (FIG. which acts on spindle 20 and drive motor 17.

Thus, according to the present invention, apparatus is provided which can automatically compensate for knife wear by continuously repositioning the knife and for grinding wheel wear by a similar action.

The operation of the device is as follows:

On beginning the cutting of a skin, the blade 4 is brought to the exact position required for the desired thickness by the manual operation of the knobs 37 or by the operation of the shaft 10 so that the strips 34 push the blade 4 into contact with the grinding surface. The grinding discs are inclined to a predetermined degree relative to the edge of the blade by rotation of the support 16. The predetermined angular relationship can be set by conforming to the indicia or vernier calibration provided on the surface of the slide member and the cylindrical sleeve 16a. It will be apparent that, because of the readily available and visible indicia, the exact angular relationship may be determined prior to setting of the device and even prior to contact with the blade. Each grinding disc and motor unit is then horizontally displaced by operation of the motor slide 15 in the manner described. It may be simultaneously displaced vertically by operation of the slide 14 until the exact position is reached for producing the desired cutting edge on the blade 4. Because the cutting angles are parallel to the planar frontal surfaces 22a of the discs 22, they are consequently rectilinear with the axis of the cylinder 16 and bear a direct angular relationship to the angle indicated on the scale 32.

Operation of the splitting machine may then continue and the skins successively split. During operation, wear on the discs 22 and on the blade 4 will both be observed and/or may be checked by the use of suitable automatic instruments. The wear on the disc 22 is compensated by a gradual movement of the motor and disc unit in a vertical direction. This gradual movement may be automatically obtained by means of electrical pulses derived from a timing device and transmitted automatically to the electromagnet 38, which consequently through operation of the core 39 and pawl 40 moves the wheel 24a and the screw 24 to adjust the slide 14 with respect to the fixed bracket 13. Signals may also be obtained by using suitable counters, RAM devices, etc.

The advance of or repositioning of the knife and/or grinding wheels may be controlled by a known magnetic detector which is located on the machine, so as traverse the knife edge. The magnetic detector controls a switch provided with two positions, the first for operating the gradual movement of the knife, the second to operate the gradual movement of the grinding wheels position. Preferably, the two positions are taken sequentially, that is the correction of the grinding wheels is only made after correction of the knife position. The second position of the switch may be interlocked with a pair of timers by which the guiding wheel is repositioned according to a predetermined interval of operation of the actuator shown in FIGS. 6 and 7 (as for example 2 minutes). The second timer may be used to provide the return pulse of short duration (e.g., 2 seconds). The degree of sharpening or action of the grinding wheels on the knife is a function of the time of interval between two sequential movements of the grinding wheels A greater degree of sharpening can thus be obtained by shortening the interval of the first timer. A softer sharpening may be obtained by lengthening the interval of the same timer.

The sequential movement of knife and grinding wheels is cyclically repeated so that a constant adjustment and repositioning is made to maintain the knife edge at the optimum distance a.

It will be obvious that the average wear on the grinding discs may be predetermined. Suitable automatic devices may, therefore, be used to provide the movement of the blade with a minimum of parts. It is possible to obtain signals, indicia or other stimulae for moving the vertical, horizontal slides as well as the blade 4 by means of a photoelectric cell or a magnetic detector or the like, each of which will produce a pulse or signal which may be used to control the rotation of the respective operating shafts. Preferably, the blade 4 is to be maintained against the surface of the grinding disc with a uniform constant pressure, thereby retaining true rectilinear relationship between the blade and the grinding surface and a uniform cutting or grinding action. During either manual or automatic adjustment, the tangential contacting points between the grinding disc and the blade 4 remain constant and the cutting edge or cutting angle of the blade do not vary. As a result, horizontal, vertical and angular adjustments can be made with the use of the simple mechanisms and structure described herein as distinguished from the more complex and costly mechanisms known in the prior art.

The mechanism for vertically and horizontally advancing the grinding discs and the mechanism for horizontally advancing the blade are interconnected by suitable control means whereby the advance of one is stopped when the advance of the other takes place. Therefore, compensation for wear on either the blade or grinding discs may be made independently and without interference from the compensation made for the other. In this manner, the blade may be kept in an exact position and the advance of the grinding discs may be so regulated so that the sharpening pressure between the disc and the blade remains constant and uniform. Controls for advancing the grinding discs and advancing the blades are conventional in nature and may include a blade sensing device and control means for the slide operating shafts which are electrically connected in such a manner that, when the blade position sensing member indicates that the blade is worn, it stops the advance of the grinding discs and begins an advance of the blade, returning it to the correct initial position, and after which the device for advancing the grinding discs resumes its operation.

From the foregoing it will be obvious that there is provided a simple and effective mechanism for effeciently controlling the sharpening of endless blades in skin splitting machines. The device may be manually operable or is readily operable by suitable electric, electronic, or other automatic mechanical means. The present invention overcomes the drawbacks of the prior art by enabling the swift and efficient compensation for wear on either the blade or grinding disc and for maintaining the blade and grinding disc in perfect condition at a uniform and constant cutting angle so that uniform splitting of the skins is maintained throughout the operation of the machine.

Various modifications and changes may be made to the device as described. The description is intended to be illustrative only of the present invention and is not intended to be limiting in any manner.

What is claimed:

1. Apparatus for sharpening the cutting blade in a skin stripping machine, said cutting blade comprising an endless belt-type blade entrained over a pair of spaced pulleys, said apparatus comprising a pair of cupshaped grinding discs having a planar frontal surface, one disposed on one side and the other one on the other side of one run of said belt, means mounting each of said discs for rotation about the central axis thereof and for movably adjusting said discs vertically and horizontally with respect to said blade, and for adjusting the angular position of the planar frontal surface with respect to the edge of the blade, the mounting and adjusting means for each disc comprising a bracket, a first slide mounted on said bracket for vertical movement, a second slide mounted on said first slide for horizontal movement, and a third slide mounted on said second slide for rotation about its axis, said disc being rotatably journaled about a shaft mounted on said third slide, and means for independently moving each of said slides.

2. The apparatus according to cliam 1, including a motor mounted on said third slide and means connecting said motor and said disc whereby said motor operates said disc while simultaneously moving in a vertical, horizontal and rotary direction with it. 3. The apparatus according to claim 1, including means for automatically moving selected ones of said slides in response to a predetermined time interval.

4. The apparatus according to claim 1, including means for automatically moving selected ones of said slides in response to the relative wear of said blade and said grinding discs.

5. The apparatus according to claim I, wherein said second and third slides are provided with cooperating indicia indicative of the relative displacement thereof and means for locking said slides in fixed predetermined alignment.

6. The apparatus according to claim 1, including means for advancing said blade toward and away from said grinding discs.

7. The apparatus according to claim 6, including means interconnecting said blade advancing means and said means for independently moving each of said slides whereby selective movement of said grinding discs and blade may be accomplished.

* i t I.

Patent Citations
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Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US5027559 *May 4, 1989Jul 2, 1991Camoga S.P.A.Sharpening unit for leather splitting machines
US6601494 *Sep 6, 2000Aug 5, 2003Armstrong-Blum Mfg. Co.Wide sweep tilting mechanism for a band saw
US7464632Feb 7, 2006Dec 16, 2008Premark Feg L.L.C.Product fence for a food slicer
US7549363Feb 7, 2006Jun 23, 2009Premark Feg L.L.C.Product table for a food slicer with hollow peripheral reinforcements
US7637191Feb 7, 2006Dec 29, 2009Premark Feg L.L.C.Product table lock for a food slicer
US7832317Feb 7, 2006Nov 16, 2010Premark Feg L.L.C.Gage plate alignment mechanism and method for a food slicer
US8043142Feb 7, 2006Oct 25, 2011Premark Feg L.L.C.Sharpener carried by the product table of a food slicer
US20070044605 *Feb 7, 2006Mar 1, 2007Zeeb Scott MGage plate alignment mechanism and method for a food slicer
US20070044621 *Feb 7, 2006Mar 1, 2007Rote Scott JTop mounted operator interface for a food slicer
US20070044622 *Feb 7, 2006Mar 1, 2007Zeeb Scott MProduct table lock for a food slicer
US20070044626 *Feb 7, 2006Mar 1, 2007Bondarowicz Frank AOvermolded food product table support arm for a food slicer
US20070044627 *Feb 7, 2006Mar 1, 2007Clem Todd LSpeed and stroke control method and apparatus for a product table of a food slicer
US20070044628 *Feb 7, 2006Mar 1, 2007Rote Scott JRear pivot pusher for a food slicer with clearance position
US20070049181 *Feb 7, 2006Mar 1, 2007Zeeb Scott MSharpener carried by the product table of a food slicer
US20070180971 *Feb 7, 2006Aug 9, 2007Zeeb Scott MProduct fence for a food slicer
US20100064872 *Sep 12, 2008Mar 18, 2010Anatoly GosisProduct fence for food slicer
US20100089254 *Oct 14, 2008Apr 15, 2010Anatoly GosisFood slicer and associated food product pusher
U.S. Classification83/174, 451/420, 69/10
International ClassificationB24B3/36, B24B3/38, B24B3/00
Cooperative ClassificationB24B3/36, B24B3/38
European ClassificationB24B3/36, B24B3/38