US2841829A - Dehairing apparatus and method - Google Patents

Description

July 8, 1958 E; J. STRANDINE ETAL 2,841,

DEHAIRING APPARATUS AND METHOD Filed Oct. 20, 1955 EZDO/V STRAND/IVE FHA/V675 6. CO/V/V/CK BY A ATTORNA-"V Unite States Patent DEHAIRING APPARATUS AND METHOD Eldon J. Strandine and Francis G. Connick, Chicago, Ill., asslgnors to Swift & Company, Chicago, 111., a cor poratlon of Illinois Application October 20, 1955, Serial No. 541,635

7 Claims. (Cl. 19-2) This invention relates to an apparatus and method for removing hair or wool from animal pelts. More particula rly, the invention relates to a method and apparatus especially adapted for removing wool from sheepskin in a largely automatic fashion.

The conventional method of removing wool from sheepskin necessitates painting the pelts on the flesh side with a suitable depilatory solution, for example, a mixture of sodium sulfide, calcium hydroxide and water. After a pelt has been treated in this fashion, it is ordinarily allowed to stand for a considerable period of time under high humidity conditions. This treatment destroys the wool roots together with a portion of the wool fiber adjacent the roots and frees the fiber from the slat to which it adheres, thereby making the final wool removal step a relatively easy one. At this point, the wool is so loosened that it may be manually pushed or lifted from the pelt.

A number of other methods have been proposed at one time or another. For example, the pelts, either painted or not, may be allowed to stand for such a period of time that the hide and flesh deteriorate to a point where the Wool is largely free. Some methods involve the use of various proteolytic enzymes, such as those of the pancreas glands or molds. These methods also result in damage to both hide and wool of one degree or another. Less destructive or milder reagents may be used to loosen wool or hair but more energy is then required to pull the mass of fibers from the hair follicles. It has been suggested that wool removal might be facilitated by employing a solution of ammonium hydroxide rather than strong alkalis or acids which have been applied as depilatories in the past. While this type of treatment does partially loosen the wool from the hair follicles, it is ordinarily inadequate, at least where methods involving hand pulling are practiced. This is true unless excessive quantities of the ammonia solution are used. Cost considerations plus the fact that the use of large quantities, even of a relatively weak alkali, can result in damage to the fibers, have discouraged widespread use of processes of this type.

It is, therefore, an object of this invention to provide an apparatus for removing hair or wool from pelts which eliminates the necessity for painting of the pelts with strongly acidic or alkaline depilatories.

It is a further object of this invention to provide a novel process for removing hair from hides and particularly sheepskins wherein moderate quantities of a solution of ammonium hydroxide adequately serve as the agent for loosening the hair from the follicles.

A further object of this invention is to provide an apparatus which is capable of stripping hair from hides and skins in a largely automatic fashion and is also capable of separating fibers from greasy or semi-fluid extraneous material.

Additional objects and advantages of this invention if not specifically set out will become apparent to one 2,841,829 Patented July 8, 8

skilled in the art during the course of the following description.

The present invention relates broadly to an apparatus and method for gripping wool and stripping it from the skin in which it is imbedded. The apparatus comprises a plurality of rollers mounted in pairs and operatively associated with conveyor means which feed wool containing pelts to the various rollers. The first pair of rollers move at about the speed of the conveyor and are closely enough placed one above and one below the conveyor to tightly hold and thereby control the movement of the pelt being treated. Immediately beyond the first pair of rollers is placed another similarly mounted pair, the lowermost roller of which turns with the conveyor at a speed equivalent to that of the first pair. The roller positioned above the conveyor moves at a speed somewhat greater than that of the other rollers so that it exerts a pulling force upon any hair or wool which it touches. The latter roller is provided at spaced intervals about its surface with a plurality of longitudinal ridges or fins which aid in gripping and pulling the wool to be loosened. Another roller on top of the conveyor belt, near the end of the conveyor, turning with the speed of the conveyor compresses and holds the pelt tightly against the conveyor.

A third pair of rollers are mounted at the discharge end of the conveyor and, like the others, are disposed transversely of the moving conveyor surface. Preferably these rollers are placed at the point at which the conveyor belt turns downwardly before beginning its return to the forward end of the dewooling apparatus. However, obviously these rollers may be located at some other point adjacent the outer surface of the conveyor. These rollers are substantially contiguous along one entire longitudinal surface and must be close enough to the conveyor to grip and apply a pulling force to the partially loosened wool. The pelt-bearing conveyor does not pass between these rollers. Their function is simply to grip and pull upon the wool while allowing the cleaned or stripped pelt to drop freely upon a second conveyor or into a suitable collecting device. These rollers are so closely placed relative to one another that the slat does not pass between them. It has been found that the prevention of the passage of the slat between these two rollers may be effected by constructing the lowermost of a rigid material such as steel and the upper roller of a resilient substance such as rubber.

One particularly important use for the machine is in connection with hide treatment with a mild depilatory such as a weak solution of ammonium hydroxide which loosens the hair or Wool only moderately (to an extent that it is difficult to separate hide and fiber by hand). The selection of such a weak depilatory avoids injury to both hide and fiber such as might result where acid or alkali hydrolysis, heat hydrolysis or digestion methods are employed. A more complete understanding of the device may be gained by reference to the following description and accompanying drawings.

In the drawings:

Figure l is a side View in perspective of an apparatus embodying features of the present inevntion.

Figure 2 is a schematic side elevational view through the apparatus illustrating the operation of the rollers and conveyor.

Figure 3 is a transverse vertical sectional view through the ridged roller.

Figure 4 is an isometric view of a flutter blade roller which maybe substituted for the pulling roller-scrapers shown in Figure 1.

Referring now to the drawings in which like characters refer to like parts throughout: the apparatus and driving means comprise generally a frame or table 10 resting upon suitable legs or similar support means 11. Conveyor belt 12 is mounted by means of supporting rollers 13 and 14 having their respective shafts extending through and journaled in axially aligned bearings mounted in the sides of the table 10. The conveyor supporting roller 14 is driven by means of pulley 15 to which is attached belt 16 which in turn is connected to pulley 17 of electric motor 18. The uppermost portion of conveyor belt 12 is partially supported by small diameter traversely mounted rollers 19, suitably bracketed or similarly mounted upon table 10. Each of the idler rollers 20 are also journaled in bearings axially aligned with one another in the sides of table 10. These idler rollers provide support for the lowermost portion of conveyor belt 12.

Beyond the feed end of the apparatus are two cooperating coextensive rollers 21 and 22 (shown in Fig. 2), the respective shafts of which extend through axially aligned bearings mounted in the table sides. Roller 21 is positioned just above the upper surface of conveyor belt 12 and roller 22 just beneath. The two are closely spaced so that if a skin is placed upon the conveyor surface and fed between them, it will be securely held in place. In other words, these two rollers operate in a fashion similar to the wringer rollers on an ordinary washing machine. Roller 22 is provided with a suitable gear 23 mounted at one end thereof on the extending portion of its shaft. Similarly, roller 21 is provided with a gear 24 also fixedly attached to the extending portion of its shaft. These two gears mesh and coact so that the two rollers may be caused to turn toward one another on the application of power to either one. In the apparatus shown in Fig. 1, gear 23 is provided with a pulley 25 also fixedly attached to the extending portion of the shaft of roller 22. This pulley is in turn connected through belt 26 to the pulley 27 of motor 18.

Just forwardly of roller 22 is a similarly positioned roller 28. This roller is similar to roller 22 in that it is mounted beneath the conveyor belt surface and is contiguous thereto. It is also held in position by a shaft journaled in suitably axially aligned bearings which are in turn mounted in the table sides. On one end of the shaft is a gear 29 to which is connected a pulley 30 driven by means of previously mentioned belt 26. Mounted just above this roller and above the conveyor belt is another roller-like member 31 which in a fashion similar to the others previously discussed, is journaled in bearings mounted in the sides of the table 10. This roller, however, is constructed differently than the others in that it is provided with a plurality of longitudinally extending ridges or fins 32 which extend radially about the surface. The ridges, strips or fins are constructed of steel or other rigid material. They run parallel to the roller. Mounted on the outwardly extending portion of the shaft carrying roller 31 is a relatively small gear 33 which meshes with gear 29 of roller 28 in such a fashion that rotation of the lowermost roller drives the upper. This uppermost gear 33 is of a relatively small diameter so that it is possible to drive roller 31 at a greater speed than that attained at any given time by the roller 28.

Attention is now directed to the right hand end of the table, the discharge end. Two substantially coextensive rollers 36 and 37 are mounted in parallel fashion so that they touch one another along a line extending the entire length of the longitudinal surface of each. Each has shafts journaled in bearings mounted on the sides of table 10. Positioned on the one extending end of each of these shafts are cooperating gears 38 and 39. The uppermost of these, 38, meshes with gear 40 mounted on the outwardly extending portion of the shaft of conveyor roller 14. Rollers 36 and 37 are preferably mounted one slightly above the other almost in contact with the conveyor belt at the point at which the conveyor first turns downwardly prior to starting its return trip to the feed end of the stripping machine. It may be observed,

however, that rollers 36 and 37 may be positioned at some other point near the discharge end of conveyor 12 as long as the plane to which rollers 36 and 37 are mutually tangent along their line of contact, is maintained perpendicular to the conveyor surface along the line of intersection of that plane and the conveyor surface. Both rollers move at a relatively high speed when power is supplied to pulley 15, because of the fact that gear 40 transmits such power to gear 38 and in turn to gear 39.

Suitable scrapers 41 and 42 are mounted on table 10. These scrapers rest against the surfaces of rollers 36 and 37 and serve to dislodge any wool or hair which adheres to such rollers. As an alternative to scrapers 41 and 42 the apparatus shown in Figure 4 may be used. The figure shows a flutter blade roller constructed of a Square or cylindrical piece of metal or wood tubing 43 to which rubberized belting material 44 is held with bolts or rivets 45. The blades 44 are flexible and bend readily. The unit is mounted on a shaft 46 which may be journaled in bearings (not shown) in such a position that either or both of scrapers 41 and 42 are replaced. Of course, two such flutter blade units, driven by suitable belting connected to a motor may be employed, one for each roller 36 and 37.

Also preferred is a holding roller 47, the shaft of which is journaled in frame 48. This roller needs no power source other than the conveyor belt with which it is frictionally engaged. Its function is to tightly grip the skin with the aid of roller 14, just before it reaches the pulling rollers 36 and 37.

As mentioned heretofore, limited pretreatment of the skins to loosen the wool or fiber somewhat is ordinarily necessary. A preferred process involves treatment with a weak ammonium hydroxide solution. For example, the pelts may be soaked overnight in a 0.2 to 0.8 molar solution of ammonium hydroxide; the ratio of weight of solution to skin weight being about 8 to 1. If intermittent agitation is provided, the soaking time may be reduced to about four hours. The temperature of the bath will ordinarily be about 50 to F. Following the chemical loosening step, warm water may be used to heat the skin to to F., i. e., above the melting point of the natural greases of the skin.

The following example is for purposes of illustrating a typical chemical pretreatment operation. However, it is to be borne in mind that the invention is not limited to this specific type of chemical preloosening and that any process which does not destroy hair and skin may be used for preparing the skins for treatment in accordance with the invention.

One thousand pounds of sheep skin were immersed in 8,000 pounds of 0.5 molar NH OI-I solution. The bath temperature was held at 6070 F. and the soaking continued for 16 hours. The skins were then removed from the vat and rinsed for 20-30 minutes in 110 F. water. The skins were drained and fed through the machine in the fashion described in detail below.

The hide or pelt to be dehaired or dewooled after being pretreated as just outlined is placed upon the feed end of conveyor 12. The hair on the pelt extends upwardly. Power is transmitted from the motor 18 through belt 16 to roller 14 which in turn causes the conveyor to move forward. The pelt is advanced to rollers 21 and 22, which, by means of power supplied from motor 18 to pulley 25 and because of the fact that each roller is connected to the other by means of the gearing mounted on its extending shaft, rotate at about the speed of the conveyor. The rollers are so closely placed that they in fact aid in moving the conveyor in a forward direction. Because of their close proximity one to the other, they also grip and securely hold the pelt being dewooled; that is, the pelt necessarily advances only at the speed of the conveyor and will not slip upon the conveyor surface while it is between these rollers. As soon as the lead edge of the pelt has passed from beneath these holding rollers 21 and 22, it passes beneath pulling roller 31 which cooperates with the supporting roller 28. This lower roller 28 rotates at about the speed of the holding rollers 21 and 22. The gear 29 mounted on the extending shaft of roller 28 meshes with gear 33 which is in turn mounted upon the extending shaft of pulling roller 31. Because of the fact that gear 33 is somewhat smaller than gear 29, the ridged pulling roller moves at a somewhat greater speed than either the conveyor, skin or the other rollers. The circumferentially mounted ridges 32 therefore exert a pulling action upon the hair or wool on the skin surface whereby the hair or wool is substantially loosened from the follicles and many of the fibers are pulled almost free. After passing through these cooperating rollers 28 and 31, the skin bearing the partially loosened fibers is advanced by conveyor belt 12 to the end of table at which point the belt turns in a downward direction prior to beginning its return to the feed end of the dewooling apparatus. As previously mentioned, the rollers 36 and 37 are mounted in parallel fashion transversely of the conveyor belt in close proximity to the arc described at this point by the conveyor belt and supporting roller. The leading edge of the hide, therefore, passes in a downward direction between rollersupported belt 12 and rollers 36 and 37 and the trailing portion is held by roller 47 cooperating with roller 14. Cooperating rollers 36 and 37 are rotated toward one another by means of gears 38 and 39 as well as driving gear 40, pulley 15, belt 16, and motor 18. Their direction of rotation is shown in Fig. 2. Their action is to grip the partially loosened hair or wool and completely separate it from the slat. The two rollers are so closely placed that they firmly grip the individual fibers while preventing passage of the pelt itself. Their relatively high rate of rotation causes them to contact virtually all hairs extending from the hide surface. Since the skin is generally in a dampened condition at the time that it is fed into the dewooling machine, it has been found that the fibers will mat and adhere, usually in relatively large clumps, to the surfaces of these two pulling rollers 36 and 37. For this reason, scrapers 41 and 42 are mounted at an acute angle to the roller surfaces. Alternatively, one or more rotating flutter blade rollers may be used to clean the pulling roller surfaces.

It has been found that the pulling rollers 36 and 37 are most effective in preventing passage of the slat if the lowermost is constructed of rigid material such as steel. The uppermost roller 36, however, is preferably of a resilient material such as rubber. An effective gripping action is thereby provided.

After completion of the dehairing operation, the conveyor 12 drops the cleaned slat into a suitable receptacle or onto a conveyor and the wool fibers are similarly collected, cleaned, and further treated.

As alternatives to holding roller 47 other devices may be used to insure that the hide is pressed tightly against the conveyor 12 and is not pulled through rollers 36 and 37. For example, a series of parallel wires may be tightly strung on top of and against the conveyor belt at the point where it contacts roller 14. The wires are placed at right angles to the rollers and, While generally following the contour to roller 14, are spaced from the conveyor belt at the feed end so that skins will be guided between said wires and roller 14. The wires move codirectionally with the conveyor and thereby squeeze the wool or fiber bearing skin tightly against the conveyor as it passes the pulling rollers 36 and 37. The fibers slip between the wires and are gripped and freed from the slat by these pulling rollers.

Preferably, conveyor belt 12 is provided with two rectangular holes 51. In one manner of operation of the machine the two hind shanks of the pelt are thrust through these holes so that as the pelt is being stripped of its Wool by the action of rollers 36 and 37, it is firmly held against 6 roller 14 by means of the two hind shanks being caught between roller 14 and the inside of the belt 12. The hind shanks of the pelt are fed through the machine in the leading position and the remainder of the pelt trails behind.

A holding roller 49 is advantageously provided to frictionally engage the partially stripped pelt and to maintain the tension necessary to hold the stripped portion of the pelt against roller 14 as the trailing portion of the pelt is being stripped. This is desirable since the shanks held in place by roller 14 become disengaged from the roller as soon as the belt and roller depart at their point of tangency and the pulling force exerted by the trapped shanks is no longer in existence. Roller 49 is driven by a gear 50 which in turn is driven by gear 40.

Roller 49 may be eliminated and clamps substituted in place of holes 51 for holding the pelt firmly in place at all times. Another alternative is to make roller 14 so large that the pelt would be completely stripped of wool before the shanks are released at the point of tangency.

It is seen that by the use of the apparatus of this invention, it is possible to effectively dehair or dewool pelts which have been only subjected to the action of a mild depilatory since an effective gripping and pulling action is achieved. The necessity for strong alkaline materials which destroy a portion of the wool while they are loosening the fibers from the hair follicles is eliminated. Furthermore, once the pelt has been fed to the lead end of the machine, the operation is completed in a largely automatic fashion. No further hand manipulation is necessary in separating the fibers and slat from one another.

Obviously, many modifications and variations of the invention as hereinbefore set forth may be made without departing from the spirit and scope thereof, and therefore only such limitations should be imposed as are indicated in the appended claims.

We claim: I

1. Apparatus for dehairing skins comprising: means for abraiding and loosening the hair on said skins; means for controlling the motion of said skins while they are being subjected to the action of the abraiding and hair loosening means; and means following said loosening means for gripping and applying a pulling .force to said hair while simultaneously preventing movement of the skin codirectionally with the said pulling force.

2. Apparatus for dehairing skins comprising: a pair of rollers rotatable in opposite directions; a second pair of rollers closely spaced laterally from said first pair of rollers, each roller being rotatable in the same direction as the corresponding roller of the first pair of rollers; one of said second pair of rollers having a roughened surface adapted to loosen the hair adhering to skin surfaces; means for rotating three of the four rollers at substantially identical speeds; means for rotating said rough surfaced roller at a speed in excess of the speed of the other three rollers; conveyor means operatively associated to advance a skin between the rollers of each pair sequentially; and a third pair of coacting rollers positioned adjacent the discharge end of said conveyor means to grip and apply a pulling force to the hair while simultaneously preventing movement of the skin codirectionally with the said pulling force.

3. Apparatus for dehairing skins comprising: a pair of substantially coextensive rollers normally adjacent one another and rotatable in opposite directions; a second pair of substantially coextensive rollers normally spaced adjacent one another, each roller being rotatable in the same direction as the corresponding roller of the first pair of rollers, and closely positioned laterally from the first pair in a plane substantially parallel thereto; one of the second pair of rollers having a roughened surface adapted to loosen hair adhering to skin surfaces; means for rotating three of the four rollers at substantially identical a speeds; means for rotating said rough surfaced roller at a speed in excess of the speed of the other three rollers, conveyor means operatively associated to advance a skin between the rollers of each pair sequentially; and a third pair of substantially coextensive rollers positioned adjacent said conveyor means at the discharge end thereof to grip and apply a pulling force to hair While simultaneously preventing movement of the skin codirectionally with the said pulling force.

4. Apparatus for dehairing skins comprising: a pair of substantially coextensive rollers normally adjacent one another and rotatable in opposite directions; a second pair of substantially coextensive rollers normally spaced adjacent one another, each roller being rotatable in the same direction as the corresponding roller of the first pair of rollers, and closely positioned laterally from the first roller pair in a plane substantially parallel thereto; one of said second pair of rollers having a plurality of circumferentially spaced ridges adapted to rub against and loosen hair adhering to skin surfaces; means for rotating three of the four rollers at substantially identical speeds; means for rotating said ridged roller at a speed in excess of the speed of the other three rollers, conveyor means operatively associated to advance a skin between the rollers of each pair sequentially; and a third pair of substantially coextensive rollers positioned adjacent said conveyor means at the discharge end thereof to grip and apply a pulling force to hair while simultaneously preventing movement of the skin codirectionally with the said pulling force.

5. Apparatus for dehairing skins comprising: a pair of substantially coextensive rollers normally adjacent one another and rotatable in opposite directions; a second pair of substantially coextensive rollers normally spaced adjacent one another, each roller being rotatable in the same direction as the corresponding roller of the first pair of rollers, and closely positioned laterally from the first roller pair and in a plane parallel thereto; one of second pair of rollers having a roughened surface adapted to loosen hair adhering to skin surfaces; means for rotating three of the four rollers at substantially identical speed; means for rotating said rough surfaced roller at a speed in excess of the speeds of the other three rollers, conveyor means operatively associated to advance a skin between the rollers of each pair sequentially; and a third pair of substantially coextensive rollers positioned at the discharge end adjacent and above said conveyor means to grip and apply a pulling force to hair while simultaneously preventing movement of the skin codirectionally With said pulling force.

6. Apparatus for dehairing skins comprising a conveyor for moving the skins, holes in said conveyor for inserting the shanks of the skin to hold the skin on the conveyor, a first set of rollers working in cooperation with said conveyor to loosen the hair from the skins and a secondset of rollers both of which being located adjacent the conveyor and adapted to pull the loosened hair from the skin.

7. A method of separating wool from the skin to which it adheres which comprises: subjecting the pelt to be dewooled to the action of a solution of ammonium hydroxide; mechanically rubbing the surface of the pelt so treated to partially loosen the Wool; and thereafter placing said pelt so treated in a zone wherein said Wool is subjected to a gripping and pulling force; and simultaneously therewith holding said pelt whereby to prevent movement of the skin codirectionally with the said pulling force.

References Cited in the file of this patent UNITED STATES PATENTS 2,143,422 Plass Jan. 10, 1939 2,151,930 Messing et a1. Mar. 28, 1939 FOREIGN PATENTS 2,434 Australia of 1931 23,524 Great Britain of 1906 307,063 Italy Apr. 11, 1933 OTHER REFERENCES Progress in Leather Science: 1920-4945, British Leather Manufacturers Research Association, London, England (1948.)

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