US2551129A - Decorticating apparatus - Google Patents

Description

y 1951 T. A. HULFISH ET AL 2,551,129

DECORTICATING APPARATUS Filed July 12, 1946 3 Sheets-Sheet l N INVENTOR.

THOMAS A. HULFISH, AND

W-ILLIS G. W DO (Tl BY QMA. -7

' THEIR A RNEY T. A. HULFISH ET AL DECORTICATING APPARATUS 3 Sheets-Sheet 2 INVENTOR. THOMAS A. HULFlSH, AND

WILLIS G. W LDO fll .7 THEIR ORNEY 31 a 6 I n A May 1, 1951 Filed July 12, 1946 y 1951 T. A. HULFISH ET AL 2,551,129

' DECORTICATING APPARATUS Filed July 12, 1946 3 Sheets-Sheet 5 l N VENTOR Th'omns A. Hans/1.

' )Y/ 4/: .Wmoo.

7Wf/l ATTORNEY Patented May 1, 1951 UNITED STATES ATENT OFFICE DECORTICATING APPARATUS Thomas A. Hulfish, Alexandria, Va., and Willis G.

Waldo, 'Washington, D. 0.; said Hulfish assignor to said Waldo Our application is a division of our copending application Serial No. 603,780 of July 9, 1945, entitled Decorticating Process and the invention relates to the decortication of best fibers; more particularly it concerns a novel method for removing the waste plant material in which such fibers are embedded without recourse to shearing or cutting action. As well, the invention treats of a novel machine for carrying such method into execution.

Among the objects of our invention is the provision of a rapid, positive and reliable method and apparatus for decorticating hast fibers of high tensile strength, including ramie and the like, in which the waste material surrounding the bast fibers, including pith, gums and the like, is removed in a highly reliable manner and in the substantial absence of any requirement for nicety of adjustment of the apparatus, in which the apparatus is simple, compact and relatively ments and features of construction, in the several operational steps, and as well, in the combination of each of the same with one or more of the others, the scope of the, application of all of which is more fully set forth in the claims at the end of this specification.

In the drawing, wherein we disclose one embodiment which we prefer at present,

Figure 1 is a simplified perspective view of a machine according to our invention, certain parts being omitted for clarity, while Figure 2 is a transverse sectional view of the machine, and

Figure 3 is a view of a modified form of drum which may be used in the machine of our in vention. Y

As conducive to a more thorough understanding of the purpose, extent and scope of our invention, it may be noted that many plants, weeds, and the like are exteriorly sheathed by .what may be likened generally to bark,- In

6 Claims. (CI. 19-12) plants of this general character, this sheathing comprises tough, spindle-shaped and thickwalled fibers or cells, known as bast fibers or bast' cells. These fibers have been found to be highly desirable in the manufacture of many fabricated articles, such as rope and the like. As illustrative of the foregoing, ramie may be cited as a vegetable product including bast fibers which, upon extensive tests, are found to display enormous tensile strength. In fact, fibers obtained from the bark of this Chinese weed have a tensile strength closely corresponding to that of steel. In View of the recognized importance, usefulness and desirability of the fibers of this weed, it will prove advantageous to consider the general mode of obtaining the bast fibers of this weed as heretofore practiced in the art prior to the introduction of our new method and machine, the operation of which latter constitutes one mode of carrying our new method int-o execution. V

Ramie in its matured stalks averages about seven feet in height and possesses a stalk some six feet in length, the remaining length comprising the leafy top. A typical stalk has a solid stem witha pithy or woody interior and a thin-skinned outer shell. Like wheat, the ramie is cut with a harvester, whereupon the stalks are gathered together and tied in bundles, as by means of a reaper or hinder. The leafy tops are cut from these bundles, leaving only the stalks for subsequent processing. The sheared tops either may be discarded or dehydrated and employed as food for livestock.

The out stalks are now ready for removal of the enveloping waste material from about the hast fibers. These latter are embedded, near the periphery of the stalks, in the gums thereof. It is this removal of the fibers which is known as decortication. A scutching operating, wherein the fibers are beaten from the stalk,-has heretofore normally been employed for this purpose.

Heretofore machines generally similar in appearance to our new machine disclosed in this application have been employed to remove the outer skin or waste material comprising part of the stalks from about the fibers. It is, however, a significant requirement of known prior art technique that these outer skins have been re moved through a cutting, shearing and scraping action; To insure proper shearing operation, steel cutting blades have been resorted to, rigidly supported and movable relative to and past a vfixed back support or anvil, sometimes called a back plate. So that proper cutting action is efiectuated, the spacing between these elements has been found to involve a critical distance of several thousandths of an inch. Either overspacing or under-spacing beyond the limits of this critical zone is found to result in failure of cutting operation or jamming of the machine. Particularly has the critical nature of this spacing demonstrated itself in the processing of bast fibers from abaca and other hard-fibered plants. Even then, the primary problem being to cut off the tough, fiber-containing skin, recourse to a subsequent scraping action has been found to be desirable.

The close spacing of the cooperating cutting elements required to effectuate proper cutting action requires disposing the cooperating cutting elements so that the distance therebetween is very substantially less than the known diameter of the stalks undergoing treatment. A crushing action between non-yielding bearing surfaces is exerted upon the stalks during their passage through the machine. As a result, and particularly as an incident to cutting hard fibers such as abaca or sisal, this crushing action causes the fibers to whip up near their ends and to become snarled. It is of course highly desirable to maintain the individual fibers of the greatest possible length, so that the finished product incorporating such fibers will display the highest possible tensile strength. To achieve this maximum fiber length, it is manifestly important to remove such possibility of whip-up and snarling insofar as this can be done.

Not only in these prior art processes and machines is cutting of the fibers resorted to, in order to remove them from the stalk, but as well there is tearing resulting from the inflexible positioning of the movable cutting blades relative to the fixed back blade which exerts further weakening action. Moreover, this nice adjustment between the cooperating elements of the prior art machines involves a critical clearance angle, so that expert supervision is required at all times, together with the attendance of skilled attendants. Appreciable expense in operation has been accepted as a necessary evil.

From the foregoing, it will readily be understood that nicety and criticalness of adjustment of the decorticating machines of the prior art constitutes a paramount consideration at all times. Satisfactory results can be achieved only when the machines are maintained at highest operating efficiencies, and while operating under skilled and highly trained maintenance and supervision. Both first costs and operating expenses are necessarily high. Any appreciable iva riation either in kind of stalks undergoing processing, or in average diameter of stalks within the particular class of plants being treated will necessitate temporary shut-down of the machine and adjustment of the blades thereof. Setting of the cutting blades during the operation of the process is impossible, either for varying the decorticating action or for any other purpose.

Moreover, decortication machines as heretofore known and available are comparatively small and of limited capacity. Because of the fine adjustment required the blades are necessarily short. Moreover, some machines have required the use of auxiliary decorticating means comprising a plurality of fine-diameter water jets operating under high pressure, participating in the decorticating action. High rotational speeds are required, effectively contribut ng .0

the Waste of good fiber so frequently observed due to whipping the fiber into tangles with subsequent breakage.

An important objective of our invention therefore is to avoid in large measure the disadvantages and difliculties attendant upon the em ployment of the techniques and machines heretofore available, and in so doing, to provide both a simplified method of decorticating bast fibers with little or no damage to the fiber and a simplified machine, for carrying that method into execution, capable of high-capacity operation with relatively slow rotational speeds, in which slippage, snarling, tangling and breakage of the fibers is substantially eliminated, in which mild softening, compressing and pushing action is exerted longitudinally of the fibers over a comparatively extended interval of time, and in which rapid and complete decortication is achieved without cutting, shaving or otherwise injuring the fiber, with large quantity output, sensitive adjustment of the decorticating action being unnecessary.

Essentially, the method of decorticatin in accordance with our invention comprises flexibly wiping the fiber strands longitudinally of their lengths at a slow rate of speed whereby the fibers are freed from the gums and pectins of the stalks and other waste material in which they are embedded with a minimum of wiping, tangling and breaking. All cutting, shearing and shaving is avoided. No decorticating, high-pressure water jet is relied upon. Inasmuch as the individual stalks are fed transversely of the direction of wiping, likewise at a slow rate of speed, so that fresh stalks may be continuously introduced. into the zone of operation, the process is a continuous one. The method therefore is adapted to quan-- tity treatment.

Low pressure water preferably hot (but cold water is also effective), is applied to the stalks during the wiping operation for softening the fibers, the surrounding gums in which the fibers are embedded, and the pithy material comprising the rest of the stalk. This softening permits the removal, in the subsequent wiping operation, of the surrounding and undesired green material, gums, etc., leaving as a remainder the desired fibrous material which is firmly gripped during the 'wiping operation.

We subject the fibrous material, throughout the wiping operation, to a comparatively slowspeed, mild, softening, compressing and pushing operation for a duration of five to ten seconds. During the latter portion of the wiping operation, the pressure with which the wiping is carried out, through the use of flexible Wiping blades for example, is increased to insure that the fibers are entirely cleansed of their surrounding debris.

Practice of our new method as set forth in the foregoing can of course be carried into execution through the use of a number of different forms of apparatus. We have, however, evolved a machine which is particularly suitable for effectuating our new method at maximum efficiency. The salient details of this machine are clearly disclosed in Figures 1 and 2 of the accompanyin drawing to which attention is now invited.

Accordingly, having reference more particularly to the drawing, We provide upper and lower endless gripping chains 10 and H, constructed of any suitable material. In one instance, we construct these chains of metal, with exposed links. To protect the which are inserted transversely between said the machine or other suitable supports.

portion I 5.

fiber stalks, however,

chains, we prefer to form the links of the chain of steel links faced with rubber, much in the manner of the conventional Caterpillar tractor tread. The upper grip chain is sprocketfed or otherwise energized for travel between sprockets or like powering means l2, I2 disposed one at each end of the machine undergoin discussion (Figure 2). With this disposition of the sprockets, it will be seen that the chain travels continuously along the length of the machine. The sprockets I2 or like means may be poweredin any suitable and conventional manner (not disclosed).

The sprockets 12 are carried by suitable hangers or brackets I3, 13 flanged at their upper surfaces l4, 4, for mounting on the frame of Hangers I 3, I 3 terminate at their lower end in a yoke This yoke carries in its arm portions l5, l5 a thrust plate [6, against which thrusts a coiled spring or the like I'I. Between the free end of this spring I! and the upper grip chain ID is provided a follower or bearing plate [8 which bears against the upper grip =chain l0 throughout the length of the machine and resiliently and yieldably thrusts the same against the stalks clisposed'between it and the lower sprocket chain II, shortly to be described.

Similarly, the continuous lower grip chain H is mounted on and carried by and between coopcrating sprockets or similar impelling means I9, I9, Just as in the case of chain Ill, chain II is constructed of any suitable material, such as steel or the like, but in the preferred instance, is formed with a rubber bearin surface so as to protect the fibers against injury as they are carried between the'two'chains. Sprockets 19, I9 are powered in any suitable manner, from conventional means, not illustrated. These sprockets likewise are disposed one near each end of 'the machine and are carried'in pedestal supports which terminate at their upper ends in yoke 22!, in which the sprockets I9, l9 are mounted.

,formed of steel or cast iron, but which may be of any other suitable metal or other material sufficiently rugged in character, extends the length of the machine. a typical instance, this back plate 22 is approximately six feet in length. This back plate 22 is concave in section, its curve being struck on a radius of substantial length. The upper lip of this back plate terminates at the junction defined by the two travelliing chains, while the lower end thereof terminates just short of the foundation on which the pedestal 2!! is carried.

In practice, according to the technique of our invention, and to carry into effect the method hereinbefore set forth, we feed the stalks of .ramie, or other suitable soft-fibered stalks, the fibers of which possess the desired tensile strength, between the grip chains In and II at Advantageously, and in against the fiber stalks 23. applied wiping action is exerted against these i 6 the forward end of the machine, assuming that the effective direction of travel of the chains is from the left to the right as seen in Figure 1. The stalks are disposed in their natural but detopped state on the back plate 22 in the mode most advantageous for the removal of the undesired waste and pithy material, pectins and the like. The stalks 23 are fed between chains 10 and II at the left end of the machine, and are brought down by the blades 30 so that their lengths extend around the concave back plate 22 as shown at 23, Figure 2.. Of course, if desired the direction of processing can be reversed. By means of the travelling chains l0 and II the stalks are thereupon carried slowly and at uniform feed to the right in Figure 1 along the length of the back plate 22. In a typical instance, a rate of travel of about one foot per second has been found to be quite satisfactory.

To insure softenin of the stalk material in which the fibers are embedded, they are subjected to a sprinkling action'throughout their travel with hot or cold water at low pressure from pipe 3! extending the length of the machine. This water spray softens the waste material and permits it to be wiped more readily from the fibers during the wiping operation. 1

A circular drum cooperates with the back plate 22 and-in the preferred embodiment is substantially but adjustably coaxial therewith. This drum extends the entire length of the machine. Since it is coextensive with back plate 22, then in a typical instance it is about six feet long. We find a satisfactory rotational speed to :be revolutions per minute. The drum 24 is carried in a pedestal 25 on which suitable pillow block bearings 26 are provided. Shaft 28 of the drum 24 is rotatable in these hearings. A series of arms 2'! radiates with equal angular spacing from the central spider 29 of the drum 24, the focus of which spider is comprised by shaft 28. These arms, in the preferred instance are comprised of steel, and for which solid discs may be substituted, and serve to carry flexible wiper blades. When solid discs are employed the wiper blades are supported by steel angles welded to the outside surface of the drum. The flexible wipers 30 comprised of rubber or similar products possessing the required strength and flexibility, are carried adjustably at the free ends of the arms 21. As the drum 24 rotates these flexible blades 36 bear yieldingly, :but with substantial pressure,

A longitudinallystalks throughout their lengths.

Theblades 30 extend the entire length of the machine. We find it desirable in some instances to shorten and stagger the blades as at 3011. shown for example in Figure 3. These blades exert their wiping action longitudinally of the stalks throughout the travel of these latter through the machine at right angles to their lengths.

In the practice of our invention,'the gentle, slow-speed, wiping action had is not accompanied by any shearing, scraping, or cutting. No difficulty is encountered in positionin the back plate '22 and the blades as relative to each other. No critical spacing is involved, inasmuch as no shearing or cutting action is required or desired It is sufficient that the spacing be such that the flexible blades 38 bear against the back plate 22.. Moreover, it is entirely feasible, in order to increase the cleansing action, to incline the axis of either the back plate 22 or the drum 24 relative to each other in the direction to-the delivery end of the machine, or to incline the blades with respect to the axis of the drum, the blades being either straight or curved as portions of a very flat spiral (so that only one point on a blade acts on the passing fiber at any given instant) in order to increase the decorticating action. Throughout the practice of the invention the fibers are left intact and unharmed. Very little whipping, snarling, tangling or breaking of the fibers occurs, due in large measure to the slow speed at which the operation is carried out.

When the decortication of the stalks is properly carried into effect, together with simultaneous washing in hot or cold water, thorough cleaning of the fibers and separation thereof from their encompassing material is effectively accomplished. The practice of our new method achieves a resultant product which is superior in every way to the fibers heretofore obtained according to known techniques.

Thus, it will be seen that we have provided a method and apparatus by which there is accomplished the many objects hereinbefore set forth together with numerous real and practical advantages. Our machine is essentially simple in construction. It involves a small number of moving parts, and these comparatively inexpen sive in themselves. No criticality of adjustment of the several parts relative to each other is involved. It is sufficient as has been disclosed, that the wiper blades 30 be in contact with the back plate 22. Because of the flexible nature of these blades considerable latitude is permissible as to their positioning. The resilient follower plate l3 insures that the gripping chains l and II are pressed closely against each other. Thus, the stalks are at all times securely gripped against the most vigorous wiping action. Moreover, increased decorticating action, along the length of the machine, is had Where the axis of the back plate and the drum or the drum and wiper blades are disposed at a fixed. or (in the case of the wiper blades) varying angle with each other. Absence of cutting, shearing, or scraping insures that long fibers are obtained. The gentle, slow-speed action effectively avoids the detrimental whipping, tangling and breaking which has so frequently characterized the heretofore known techniques.

The long fibers which we obtain therefore are substantially undamaged, and retain their full tensile strength.

Substantially the only attendance which is required is in connection with supply of the stalks to the machine. reduced to a minimum. The slow-speed operation of the machine lubricated by water minimizes wear. This contrasts strikingly with the rapid Wear of known machines attendant upon the high rotational speeds required for satisfactory cutting action. The length of the machine, insuring that a large number of stalks are undergoing treatment, simultaneously insures high umt output. All these and many other highly practical results are obtained according to the practice of our invention.

In as much as many embodiments of our method and apparatus will readily occur to those skilled in the art, once the broad aspects of our invention are disclosed, and since many modifications will suggest themselves of the embodiment herein set forth, we intend that the foreging disclosure be construed, not by way of limitation, but simply as illustrative.

We claim as our invention:

Thus, labor requirements are 1. A machine for decorticating stalks having a bast portion with fibers therein, said machine comprising a, rigid bearing plate having a smooth continuous surface for continuously and unyieldably backing said stalks, means for passing the stalks across said plate, and blade means flexibly bearing against and being movable along the lengths of the stalks on the bearing plate for wiping the stalks with a firm but yieldable force to remove Waste material from the fibers thereof.

2. A decorticating machine for stalks having a bast portion with fibers therein, said machine comprising a rigid concave back plate having a smooth uninterruped surface for continuously and unyieldably backing up said stalks, means for passing the stalks transversely across said back plate, a rotatable drum coacting with the concave back plate, and flexible wiper blades on said drum for wiping along the stalks on said back plate with a firm but yieldable pressure for removing Waste material therefrom and releasing the fibers.

3. A decorticating machine for fiber-bearing stalks, comprising an elongated rigid back plate having a smooth continuous surface for continuously and unyieldably backing up said stalks, means for moving the stalks along the length of said back plate with their strands extending along the surface thereof, means for projecting a stream of water onto stalks as the same are moved along the back plate, and flexible wiper blades coacting with the back plate for wiping against the stalks with a firm but yieldable pressure to remove waste material therefrom and release the fibers.

4. A machine for decorticating stalks having a bast portion with fibers therein, said machine comprising an elongated rigid metal back plate having a smooth uninterrupted concave working surface for continuously and unyieldably backing up said stalks, means for hanging a plurality of stalks over said back plate so that they extend along the bearing surface thereof and including cooperating upper and lower gripping means for said stalks adjacent the top of said back plate,

I said gripping means serving to move the stalks along the length of the machin and transversely of their own lengths, a rotatable drum substantially coaxial with said concave back plate, and cooperating therewith, and flexible wiper blades mounted lengthwise along said drum for bearing against the backed up stalks with a firm but yieldable pressure and wiping them to remove waste therefrom and release the fibers.

5. A machine for decorticating stalks having a bast portion with fibers therein, said machine comprising an elongated rigid back plate having a smooth continuous concave working surface for continuously and unyieldably backing up said stalks, means supporting said back plate, cooperating upper and lower gripping chains extending along the length of said back plate near the top thereof, a support for the lower chain and a hanger for the upper chain, a drum substantially coaxial with the concave surface of said back plate, pedestal means for rotatably supporting said drum, and flexible wiper blades mounted lengthwise along the periphery of said drum for wiping against the concave surface of said back plate with a firm but yieldable pressure.

6. A machine for decorticating stalks having a bast portion with fibers therein, said machine comprising a rigid back plate having a smooth continuous surface for continuously and unyieldably backing up said stalks, means for passing the stalks sidewise across said back plate, a rotat- 9 able drum coacting with the back plate, flexible Wiper blades positioned along the length of the drum for wiping the stalks with a firm but yieldable pressure for removal of waste material therefrom, said back plate and drum means being angularly adjustable relative to each other for varying the pressure with which the flexible wiper blades bear against the back plate throughout the length of the same.

THOMAS A. HULFISH. WILLIS G. WALDO.

REFERENCES CITED The following references are of record in the file of this patent:

Number Number 10 UNITED STATES PATENTS Name Date Stanbridge Mar. 10, 1896 Hubler Sept. 11, 1917 Reeves Feb. 8, 1944 Reeves July 23, 1946 FOREIGN PATENTS Country Date Great Britain Feb. 5, 1934

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