US3670366A

US3670366A - Automatic stripping machine for abaca and allied fiber bearing plants

Info

Publication number: US3670366A
Application number: US830449A
Authority: US
Inventors: Juan T Villanueva; Jesus T Villanueva
Original assignee: Individual
Current assignee: Individual
Priority date: 1968-06-04
Filing date: 1969-06-04
Publication date: 1972-06-20
Anticipated expiration: 1989-06-20

Abstract

A method and apparatus for defibering sheaths of fibrous material, particularly Manila hemp, by conveying the sheaths past several stationary blades arranged in the path of travel of the sheaths whereby the edges of the blades separate the fibrous parts of the sheaths from the pulpy parts.

Description

nited States Patent Villanueva et al.

[451 June 20, 1972 [54] AUTOMATIC STRIPPING MACHINE FOR ABACA AND ALLIED FIBER BEARING PLANTS [72] Inventors: Juan T. Villanueva; Jesus T. Vlllanueva,

both of 105 Apo Street, Sta Mesa Heights, Quezon City, Philippines 22 Filed: June 4,1969

21 Appl.No.: 830,449

[30] Foreign Application Priority Data June 4, 1968 Philippines ..9282

[52] US. Cl ..l9/l2 [51] Int. Cl. ..D0lb H10 [58] Field otSearch ..l9/5, 6,10,11,12, 13, 27, 19/1, 7, 8,15,17,19, 20, 34

[56] References Cited UNITED STATES PATENTS 852,410 5/1907 Barton l 9/34 1,258,571 3/1918 Humphrys ..19/8 1,390,922 9/1921 O'Neill, Jr. ....l9/l2 1,725,815 8/1929 Mertz ....l9/l2 2,759,224 8/1956 Simons ..19/1 I FOREIGN PATENTS OR APPLICATIONS 211,113 10/1957 Australia ..l9/27 23,307 7/1949 Finland 1 9/12 528,765 1 H1940 Great Britain ..19/13 Primary Examiner-Dorsey Newton Attomey-Michael S. Striker ABS I RACT A method and apparatus for defibering sheaths of fibrous material, particularly Manila hemp, by conveying the sheaths past several stationary blades arranged in the path of travel of the sheaths whereby the edges of the blades separate the fibrous parts of the sheaths from the pulpy parts.

9 Claims, 29 Drawing Figures AUTOMATIC STRIPPING MACHINE FOR ABACA AND ALLIED FIBER BEARING PLANTS BACKGROUND OF THE INVENTION I This invention relates to a method and apparatus for stripping leaf sheaths or tuxies as they are more commonly known, from the Manila hemp plant, also known as abaca and scientifically classified as musa textilis, linnaei.

Until the present time there have been only two methods used to extract the fibers from Manila hemp, namely decortication and stripping.

Manila hemp or abaca, a plant which is indigenous to the Philippines, bears a striking resemblance to the banana plant, both plants being botanically classified in the genus musa. The main difference between the two plants however is that the abaca plant is somewhat smaller than the banana plant, otherwise the plants a.re similar in many other respects, particularly in regard to their structure. The trunk, which appears to be rounded, is actually made up of crescent-shaped layers, within which the fibers are found on the outer or convex side of the crescent, and there is a pulpy material on the inside or convex side of the crescent, as well as within the body of each layer. Each crescent-shaped layer is called a leaf sheath, or more commonly, a tuxy". Each tuxy converges in an upward direction from the base of the plant to form a round stalk which becomes a mid-rib from which a leaf spreads outon either side of the mid-rib. The trunk of the abaca plant is known as a leaf stalk" before the tuxies which constitute it are separated from it.

The decortication process involves repeated beating of the tuxies by hand, or in some instances the entire trunk is beaten in order to expose the fibers. To remove the sap the fibers are simultaneously washed in a constant supply of water as the beating occurs along the entire length of the trunk. The fibers produced by this process have a dull appearance in contrast to the fibers produced by stripping. In addition, both the pulp and sap are carried away by the wash water.

In the stripping process, each leaf sheath is pulled between a stripping element comprising a blade and a wooden or plastic block which presses on the inserted leaf sheath as it passes over the blade. In this manner, the sap is squeezed out of each tuxie, first from one portion of the leaf stalk and then from the remaining portion. As a result of this operation, the entire tuxy is completely defibered without washing in such a way that only the strongest fibers pass through the stripping element while the relatively weaker fibers remain behind the stripping element together with the waste pulp. The shape of the cutting edge, i.e. plain or serrated, greatly determines the commercial grade of the stripped fibers, thus the absence of the weaker fibers makes the stripped fibers stronger and of a better quality than the fibers obtained by decortication.

Presently known machines used for decortication of Manila hemp fibers have been developed to quite an advanced state of the art, whereas the stripping process is for the most part still done by hand. A machine is presently known which is used to mechanize the stripping process, however it is .dangerous to use and its effective production is largely dependent upon the skill of its operator.

SUMMARY OF THE INVENTION It is an object of this invention to provide a novel method and apparatus for the automatic stripping of fiber-bearing plants, particularly the Manilahemp plant.

Another object of this invention is to provide a novel means for the automatic and systematic classification of stripped Manila hemp fiber.

Another object of this invention is to provide a novel mechanical means for the extraction of Manila hemp fiber from the midribs of the leaves of the plant.

A further object of this invention is to provide a novel mechanical means for the extraction of the finest grades of Manila hemp fiber.

The method of the present invention comprises the steps of positively engaging and transporting successive sheaths sideways past at least one stripping station and stripping the pulpy part from the fibrous part of the sheaths during travel v past said station.

The stripping step is carried out in a number of successive stages and the transporting step includes gripping the sheaths and imparting to them an undulate shape.

The apparatus of the present invention comprises conveyor means for positively engaging and transporting successive sheaths sideways, and stripping means including a plurality of stationary stripping blades having edges located in the path of travel of the sheaths to automatically strip the pulpy part from the fibrous parts of the travelling sheaths.

The novel features which are considered as characteristic of the invention are set forth in particular in the appended claims. The improved stripping machine however, both as to its construction and its method of operation, together with additional features and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a plan view of one embodiment of the automatic veyors, the upper chain belt conveyors, and the stripping elements;

FIG. 2 is a plan view of an alternative embodiment of the automatic abaca stripping machine showing the lower chain belt conveyors, the upper conveyors, and the stripping elements;

FIG. 3 is a schematic side view of the automatic abaca stripping machine shown in FIGS. 1 and 2 showing the lower chain belt conveyors and the stripping elements, with their respective wedge shaped openings or ingresses where the raw material is inserted;

FIG. 4 is a schematic plan view of the upper or top chain belt conveyors showing their respective locations over their corresponding lower chain belt conveyors featured in FIGS. 1 and 2;

FIG. 5 is a schematic side view of all the upper or top chain belt conveyors showing their arrangement in the stripping machine;

FIG. 6 is a schematic side view of the upper chain conveyor 40 which lies over lower chain belt conveyor 41 shown in the next drawing, i.e. FIG. 7;

FIG. 7 is a schematic side view of the lower chain belt conveyor 41;

FIG. 8 is a schematic side view of upper chain belt conveyor 42 which is placed over the lower chain belt conveyor 43 shown in the next drawing, i.e. FIG. 9;

FIG. 9 is a schematic side view of lower chain belt conveyor 43;

FIG. 10 is a schematic side view of upper chain belt conveyor 44 which is mounted over the lower chain belt conveyor 45 shown in the next drawing, i.e. FIG. 11;

FIG. 11 is a schematic side view of lower chain belt conveyor 45;

FIG. 12 is a schematic side view of upper chain belt conveyor 46 which lies over lower chain belt conveyor 47 shown in the next drawing, i.e. FIG. 13;

FIG. 13 is a schematic side view of lower chain belt conveyor 47;

FIG. 14 is a schematic side view of upper chain belt conveyor 48 which lies over lower chain beltconveyor 49 shown in the next drawing, i.e. FIG. 15;

FIG. 15 is a schematic side view of lower chain belt conveyor 49;

FIG. 16 is a schematic side view of upper chain belt conveyor 50 which lies over lower chain belt conveyor 51 shown in the next drawing, i.e. FIG. 17;

FIG. 17 is a schematic side view of lower chain belt conveyor 51;

FIG. 18 shows in cross-sectional detail the design and construction of a set of chain belt conveyors provided with ropes between which the leaf sheaths are tightly held while being conveyed through the stripping process;

FIG. 19 is a plan view of the design and arrangement of the conveyors shown in FIG. 18;

FIG. 20 is a side elevational view of the design and arrangement of the conveyors shown in FIGS. 18 and 19;

FIG. 21 depicts in cross-sectional detail an alternative conveying means in the form of a pair of flat rubber belts provided with tread corrugations containing small reinforcing cords or ropes built into the belts;

FIG. 22 is a plan view showing in detail an alternative design of the set of conveyors shown in FIG. 21;

FIG. 23 is a side view of the conveyors illustrated in FIGS. 21 and 22;

FIG. 24 shows the initial stripper element 65;

FIG. 25 shows the anterior portion of the initial stripper element 65, i.e. before the bend thereof, and in profile shows the relative position of the leaf sheath inserted between the rounded edge of the stripping blade and the wooden or plastic stripping block pressing upon it preparatory to the stripping process;

FIG. 26 shows the posterior portion of initial stripper 65, i.e. after the bend thereof, and shows in profile the relative position of the leaf sheath and the resulting fibers during the stripping process;

FIG. 27 shows the final stripper element set 74;

FIG. 28 shows the anterior portion of final stripper element set, i.e. before the bend thereof, and shows in profile the relative position of the leaf sheath upon insertion between the rounded edge of the stripping blade and the wooden 'or plastic stripping block pressing upon it preparatory to the stripping process; and

FIG. 29 shows the posterior portion of final stripper element 74, i.e. after the bend thereof, and shows in profile the relative position of the leaf sheath and the resulting fiber during the stripping process.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIGS. 1 and 2 of the drawings, power is received by the machine from any form of prime mover or from an electric motor of sufficiently large power rating through multiple V-belts applied upon a grooved pulley 100 which causes shaft 102 to turn clockwise looking in the direction of the travel of the material from the entrance end of the machine to the exit and thereof. The axis of shaft 102 is kept in position by means of journals 101. Power is transmitted mechanically from shaft 102 to shafts 103 kept in place by pillow block bearings or journals 97, through the use of either

bevel gears

98 and 99 or corresponding silent spiral gears.

The sprockets mounted and fixed or keyed to shafts 103 cause the forward movement of all the lower chain belt conveyors. Power is transmitted to the sprockets and to the conveyor driven by them directly through the shafts 103 except in the case of lower chain belt conveyor 43 where a direct drive cannot physically be arranged because of the obstacle presented by stripper element 74. This simple mechanical problem finds an easy solution in the installation of a countershaft parallel to shaft 103 to be placed possibly below it, upon which spur gears will be keyed at the ends, said countershaft to be supported by a couple of journals appropriate for the purpose so that with a ratio of l to l, motion is transmitted from spur gear 104 to spur gear 105 provided for the drive. This gear 105 is mounted upon shaft 106 running within journals 107. In this manner the lower conveyors are caused to move forward. How they cause motion of the upper or top conveyors will be explained in more detail below.

In this invention, it is proposed to have all top conveyors driven by their respective lower conveyors by means of a set of four gears, two of which to be accurately set to be always in mesh with each other while each of them are set to be always meshing with the driving and driven gears of the gear trains respectively in a conventional arrangement.

In order to derive the greatest possible advantage from the use of the automatic Manila hemp or abaca stripping machine proposed herein, a reorganization of the conventional processing methods would appear necessary.

The tuxies or leaf sheaths 81, constituting the individual leaf stalks or trunks of the Manila hemp plant from which the tuxies or leaf sheaths 81 are removed would have to first be classified and grouped together according to layer positions within the leaf stalks or trunks of the plant.

Two devices are most vital in the automated process embodied in our stripping machine, namely, the gripping conveyors featured in almost all the drawings from FIGS. 1 to 23 and the specially designed stationary stripper element sets illustrated in detail from FIGS. 24 to 29.

The gripping conveyors fundamentally and essentially would consist of only three sets, all of endless chain belt design, having difierent lengths which while operating in parallel, would have to overlap in order to yield the contemplated results. Because of structural limitations, however, what would have been the last set of conveyors is divided into four sets in order to correspondingly divide the load upon the single set of conveyors, as a result of the pull on all the tuxies or leaf sheaths 81 being gripped by the set while performing the stripping process.

Each conveyor set basically consists of two chain belt conveyors each equipped with bundles of cord or ropes rigidly fastened to the chain belts in such a manner that the ropes of the upper conveyor will fit into the spaces formed between the ropes of the lower conveyor.

As can easily be observed the lineal speeds of the two chain belt conveyors have to be identically the same so that any material tightly placed between them will be conveyed with a tightness of grip as a result of the longitudinal meshing of the ropes throughout the conveying operation.

Two embodiments of the aforementioned tuxy or leaf sheath gripping conveying scheme are illustrated in FIGS. 18, 19 and 20.

At the outset, for purposes of economy and simplicity, rubber covered ropes 83 of uniform size, preferably with the fibers thoroughly rubber impregnated are attached to each chain belt conveyor as mentioned above, in such a manner that the space between any two ropes 83 will be less than the diameters of the ropes. With the bottom conveyor of any one set having one more rope in number than the corresponding top conveyor placed over it, the ropes 83 in the bottom of the top conveyor will partially fit into the spaces and interstices between the ropes 83 placed and held firm on the top of the lower conveyors to which they are attached. Consequently, any flat fibrous material placed between the chain belt conveyors such as Manila hemp or abaca tuxies or leaf sheaths 81 or the stripped fibers resulting therefrom would be held tightly and positively in corrugated form as shown in FIG. 18 so that the upper and lower sides of the sheaths are in direct contact with the adjoining complementary surfaces of the upper and lower conveyors. The friction due to tightness of hold caused by the close fitting between the ropes 83 would be sufficient to maintain the pull necessary for the squeezing action between the blade and block in the process of stripping.

This gripping provision between the top or upper chain belt conveyors and their corresponding lower counterparts thus described has caused some design problems, however preliminary experiments and engineering calculations have shown that the two aforementioned conveying schemes are best suited for use in the present invention.

Referring to FIGS. 1, 2 and 4 and again to FIGS. 18, 19 and 20 as well as to FIGS. 21, 22 and 23, it will be observed that both schemes are based on the use of roller conveyor chains with bent attachment link plates 86 interconnected by pins 89 upon which are mounted large rollers 87 provided with grooves 88 which fit fixed rails built into rail plates 90, fastly secured onto the framework around which the conveyors travel, by flat screws 91. The purpose of this arrangement is to prevent the chain belt conveyors from veering or swerving laterally or sidewise while the sets of conveyors draw the tuxies or leaf sheaths through the apparatus during the stripping process.

Because the lengths of sheaths 81 can vary anywhere from 1 meter and centimeters (1.20 M) up to a maximum of 3 A meters (3.50 M) or 4 feet (4 feet-0 inches) up to 12 feet (12 feet-O inches) it might be desirable to incorporate additional conveyors, preferably also of the chain belt guided type, but

intended for simple plain holding of leaf sheaths 81. Re-

gardless of the aforementioned conjectures arising from a careful analysis and study of FIGS. 18, I9 and 20 as well as of FIGS. 21, 22 and 23. A clean wooden latticeor plain floor upon which the material can be dragged without getting soiled may be used instead of the additional conveyors shown in FIGS. 18 through 23.

As already stated, FIGS. 18, 19 and 20 feature exclusively details of the first scheme as described. In the first embodiment, the roller chain conveyor links 86 appear fastened to plates 84 which hold the ropes 83 by means of rivets 85. The pins 89 mentioned above, connecting link plates 86 and holding large rollers 87 appear in the drawings with the headless ends upset so as to be enlarged exactly as if they were rivets. At the outset however, the headless ends might be simply drilled in order to admit cotter pins which in combination with plain cut washers would lock the links 86 in'place. Typical leaf sheaths 81 are shown being pressed by ropes 83. In FIG. 18, four ropes 83 appear attached to the top chain belt conveyor and five ropes are attached to the lower chain belt conveyor in such a manner that the tuxies or leaf sheaths assume corrugations following the contours of the top and lower ropes 83 in alternate positions. The ropes are fastened to holding plates 84 by means of small stranded wire strings 82. 1

The pressure between the top ropes 83 attached to the upper or top as well as the bottom or lower chain belt conveyors with the tuxies or leaf sheaths 81 in between them introduces a resistance to motion or grip which results in a pull on leaf sheaths 81, by the chain belt traveling conveyors. This pull on leaf sheaths 81 overcomes the resistance offered by the squeezing action of the knife or blade and the opposing cushion block of the stripping

elements

65 and 74 encountered at appropriate spots in the travel of leaf sheaths 81 along the entire length of the machine, as shown in FIGS. 1, 2 and 3 and further detailed in FIGS. 18 through 23. The leaf sheaths are thereby converted into the desired valuable fiber as well as the by-products rendered by the process.

A second embodiment would be the result of contemplated improvements on the gripping device obtainable with the cooperation of rubber belt manufacturers. With this end in view, an endless rubber belt 92 as depicted in FIGS. 21, 22 and 23 can be positively fastened onto plates 84A by means of rivets 85A each one of which would be fiat headed on one end and headless on the other in preparation for proper conversion into a button head after attachment. The rest of the parts of the chain belt conveyor which are common to both the first design as well as to this second embodiment bear exactly the same identification numbers in the FIGURES and the gripping effect upon the moving material is due to the same fundamental principle used in the first embodiment. A distinct improvement results from the corrugations of the rubber embedded ropes or cords within the belts, in that the leaf sheaths 81 are gripped more effectively.

Having described the design and construction of the conveyor sets, another innovation worth mentioning is the design and construction of the stripper element sets which are illustrated in FIGS. 1 and 2 and FIGS. 24 to 29 inclusive.

Two specially designed stripper element sets 65 and 74, one following the other, such as are depicted in detail in FIGS. 24,

25 and 26 as well as in FIGS. 27, 28 and 29, are secured by nuts 108 tightened around foundation bolts 109 to the foundation base of the machine along the path of travel of leaf sheaths 81. The edges of the blades of the stripper element sets define boundary lines which separate the stripping blocks of the sets from the edges of the corresponding blades upon which the blocks press with the leaf sheaths 81 to be stripped inserted inbetween.

The incorporation of the stripper element sets into the present apparatus is as essential and vital to the operation of the stripping machine as are the aforementioned gripping conveyors.

An understanding of the function of the stripper element sets is essential and necessary in order to understand the role played by them in order to secure automation of the process of stripping of the Manila hemp plant while producing expeditiously the highest grades of Manila hemp fiber possible through the use of the machine.

A distinctive feature of this invention is the method of insertion of the tuxies or leaf sheaths into the stripper element sets. These sets are shown in plan view in FIGS. 1 and 2 and side view in FIG. 3 wherein the two automatic stripping outfits are seen to have elements which are common to both machines. The details would be best understood by referring to FIGS. 24, 25 and 26, wherein the first stripper element set is met by the material to be stripped for the initial defibering on the short, root-end portions or stubs of leaf sheaths 81. FIGS. 27, 28 and 29 on the other hand would facilitate a better understanding of the function of the second stripper element set intended to complete the process of stripping by working upon the remaining unstripped portions of the aforementioned leaf sheaths 81 which are carried along the conveyor path by the gripping conveyors.

As can be seen from the FIGURES leaf sheaths 81 are positively carried by the conveyors on both sides of the stripper element sets and at distinct periods of the processing are inserted into the wedge-shaped opening formed by the stripping blocks 70 and and the corresponding stripping blades or knives underneath them, namely 65 and 74 respectively, the

stripping units in assembly constituting stripper sets 65 and 74 appearing together with the conveyors in the profiles as shown in FIGS. 3 and 5. The details of the individual stripping element units are portrayed in FIGS. 24 and 27, with cross-sections at certain points of the process shown in FIGS. 25 and 26 and in 'FIGS. 28 and 29. The wedge-shaped ingresses or openings provided by the blade and block of the stripper element sets mentioned bear resemblance to the opened beaks of fowl.

Each of the stripper element sets have two ends or parts. The part or portion that first meets leaf sheath 81 which is the raw material to be processed, is the front or anterior end of the stripper element set under consideration, set 65 being the first and set 74 the last to work on the leaf sheaths. The part or portion of the set that last contacts leaf sheath 81 during the stripping process is the rear or posterior end of the stripper element sets specified.

The front or anterior end identified as 69 in FIG. 24 in the case of the first stripper set and 79 in FIG. 27 in the case of the last stripper set is placed in such a position that the direction of its blade is parallel to the line of motion of the conveyors carrying the material. Thus the directions of the blades of the front or anterior end of the stripper element sets will always be installed parallel to the direction of travel of the material being processed, so that with the wedge-shaped openings provided therewith, the stripper element sets will always be arranged to meet the material being carried by the conveyors.

A flattening of the edges of the knives or blades of the front portions 69 and 79 of the stripping

element units

65 and 74 shown respectively in FIGS. 25 and 28, with the corners of the flattened edges dulled or even ground round in order to preclude the cutting of any fibers or the pulpy sections of leaf sheaths inserted into the stripper units is a distinctive feature of the present invention.

While in principle the two stripping element sets 65 and 74 (FIGS. 1 and 2) are actually duplicates of each other, they will be found to be identical with each other only in regard to symmetry. This means that with the forelegs of the stripping element sets 65 and 74 placed in their respective positions, namely, in line with direction of travel and with their respective wedge-like openings or ingresses 63 (FIGS. 24) and 72 (FIG. 27) facing the material being conveyed, for example leaf sheaths 81, the posterior leg 71 of the first element set 65 (FIGS. 1 and 2) is directed to the left, while the posterior leg 78 of the second and last element set 74 (FIGS. 1 and 2) is directed to the right. Moreover, these

posterior legs

71 and 78 will also be found to greatly differ in length, the difference being caused by the lengths of the tuxies or leaf sheaths 81 that they will work on.

In the first stripper element 65 shown in FIG. 24, the insertion of leaf sheaths 81 between the blade of set 65 and the corresponding wooden or plastic block 70 so that it gently presses upon the blade in preparation for the actual stripping process is effected by

conveyors

41 and 40 shown in FIGS. 7 and 6 and

conveyors

43 and 42 as shown in FIGS. 9 and 8.

Similarly in the case of the last stripper element set 74 shown in FIG. 27, insertion of the leaf sheaths between the blades of set 74 and the corresponding wooden or plastic block 80 so that it gently presses upon the blade in preparation to the actual stripping process is effected by

conveyors

43 and 42 shown in FIGS. 8 and 9 and

conveyors

45 and 44 appearing in FIGS. 11 and respectively.

The rear or posterior ends of the stripper element sets start at points 64 (FIG. 24) and 73 (FIG. 27) where the entire stripper element sets veer at an oblique angle of about 45 either to the left in the case of stripper element 65 or to the right in the case of stripper element 74 dependent upon the process requirements.

Right at these points where the veering occurs, i.e. points 64 and 73 (FIG. 1), the round edges of the blades as shown in FIGS. 25 and 28, pertaining to the front or anterior portion, turn into the sharp features of the hemp stripping knives exactly as in the case of hand stripping. This is shown in FIGS. 26 and 29.

Considering the alternative design of the machine as shown by FIG. 2, which is almost identical to the embodiment shown in FIG. 1, the difference being in the construction of the rear or posterior end of the stripper element sets as shown in FIG. 2. While the rear or posterior ends of the stripper element sets of the original machine shown in FIG. 1 veer either to the left or right in straight lines to an angle of 45 thereabouts, in the alternative arrangement of FIG. 2 the rear ends are formed in the shape of an arc or semicircle which turns to either the left or to the right. Thus, if the rear or posterior ends have serrated blade edges instead of blunt blades, there will be no motion perpendicular to the line of pull upon the tuxies or leaf sheaths 81. In this manner, the darker and inferior grades of Manila hemp can be produced in the same manner as the lighter and more expensive grades which the original machine appearing in FIG. 1 is exclusively intended to produce.

Referring to FIGS. 1, 2 and 4, wherein the conveyors are shown in plan view, it will be observed that each successive leaf sheath belonging to any group previously classified according to the position or layer in the trunk or leaf stalk of the plant is fed transversally into the machine or at right angles to the direction of travel, so that leveler plate 82 will place the butt ends of the tuxies or leaf sheaths in line, while they are carried by

conveyors

41 and 43 along the respective entrance lengths or positions of the latter, as can be seen in the plan view thereof appearing in FIGS 1 and 2. Because of the absence of top conveyors above them such as are shown in FIG. 4, and considering the stiffness of the material, the leaf sheaths are free to move at the start sidewise or across the full width of the machine.

It is at this point that the additional simple or open type conveyors, previously mentioned, might be used in order to prevent dragging of the extremely long tuxies or leaf sheaths along the floor during the stripping process.

When the tuxies or leaf sheaths reach the midpoints of the

lower conveyors

41 and 43 shown in FIGS. 1 and 2, the

top conveyors

40 and 42 placed respectively over them as shown in FIG. 4, come into action by pressing down upon the tuxies or leaf sheaths of the lower conveyors, thereby holding the tuxies or leaf sheaths with a tight grip and assuring a positive pull thereupon.

With the tuxies or leaf sheaths thus held tightly by the two sets of conveyors moving in parallel, assurance of their insertion into the wedge-shaped opening 63 shown in FIG. 24 because of the tapered or bevel cuts downwards upon the stripper blade 65 and upwards upon the stripper rectangular section shaped wooden or plastic pressure blocks 70 would be established.

The leaf sheaths continue travelling after their insertion into the stripper element set, identified in assembly as 65, until they reach the veering point 64 of the stripper element set.

Meanwhile, because of the fact that the edges of the stripper blade have purposely been made round all over between

points

63 and 64, which is the foreleg portion of the stripper element set 65 instead of maintaining the conventional sharpness of comers common to the blunt stripping knives used in hand stripping, the slightest damage to the sliding tuxies or leaf sheaths during the insertion within the front or anterior portion of the stripper element set under consideration is averted and forestalled.

Upon arrival of the tuxies or leaf sheaths at the veering point 64 shown in FIGS. 1 and 24, the following events occur in succession:

First, the travel of material carried by the chain belt conveyor set made up of lower chain belt conveyor 41 and top chain belt conveyor 40 ceases because the top and lower chain belt conveyors have reached the ends of their travel upon coming to the turning points of their respective sprockets which cause their return to their starting points; Second, at the same time the chain belt conveyor set which consists of lower chain belt conveyor 43 and corresponding top chain belt conveyor 42 continues to pull the tuxies or leaf sheaths because of the tight hold which it has on them; Third, as a result of the release from the first chain belt conveyor set made up of the lower chain belt conveyor 41 and top chain belt conveyor 40 occuring during the first event, and with the steady pull of the second chain belt conveyor set composed of lower chain belt conveyor 43 pressed upon by the top chain belt conveyor 42 occuring during the second event, the leaf sheaths which have previously been inserted into the stripper set 65 up to the veering point of the latter at point 64 or slightly past this point now turn to such a position as to be approximately at right angles with the veered posterior length of stripper element set 65.

After the butt stubs at the root ends of the tuxies or leaf sheaths 81 have been stripped by the pull of the second chain belt conveyor set composed of the lower chain belt conveyor 43 and the corresponding upper or top chain belt conveyor 42 the first of the series of the last or final chain belt conveyors becomes operative in the stripping process. It is made up of the lower chain belt conveyor 45 with the top or upper chain belt conveyor 44 installed over it. The set of chain belt conveyors thus described emerges in exactly the same row or line of travel as the first set of chain conveyors mentioned made up of lower chain belt conveyor 41 paired with top chain belt conveyor 40 over it. This set of chain belt conveyors which is composed of

chain belt conveyors

45 and 44 gets hold of the defibered portion of the root ends of the partially stripped tuxies or leaf sheaths 81 at a spot adjoining the remaining unstripped lengths thereof and performs two functions: first, it contributes to the drawing effort solely exerted so far by the

chain belt conveyors

45 and 44 for the stripping of what remains of the unstripped lengths of the root end portions of the tuxies or leaf sheaths, and second, it causes the simultaneous insertion of the tuxies or leaf sheaths into the wedge opening at point 72 of the foreleg 79. The bevel cuts on the stripping blade and corresponding stripping block together make up a preliminary stripper element set 74 for the stripping of leaf end portions of the tuxies or leaf sheaths.

of the posterior leg or portion of the stripper'element to the right with respect to the direction of travel of the tuxies or leaf sheaths takes place.

The difference between FIGS. 1 and 2, is that in the machine shown in FIG. 1, the posterior leg of the stripper is in a straight line at an angle of 45 to the direction of travel, while in the machine depicted in FIG. 2, the same posterior leg is in the form of a curve which starts tangent to the line of travel and follows a circular track or curve that ends just short of 180 from the starting tangent line.

Upon arrival of. the stripped butt end of the tuxies or leaf sheaths at the veering point 73 of the stripper element set 74, (FIG. 27) the travel of the conveyor set made up of lower chain belt conveyor 43 over which top chain belt conveyor 42 is placed, is cut short at points 14 and (see FIGS. 1, 2 and 4) when, because of the turning of the chain sprockets involved, the chain belt conveyors are made to return back to their starting points. Meanwhile, the chain belt conveyor set which is made up of the lower chain belt conveyor 45 and top chain belt conveyor 44 over it, continue its travel carrying with it with a firm grip the-partially stripped tuxies or leaf sheaths 81, thereby pulling the unstripped portions past the posterior leg. 78 of the stripper element 74 made of stripping block 80 pressing -upon stripping blade 74 as whown in FIG. 27 of .thedrawings, beyond the veering point 73 which is adequately prepared to strip the remaining portions of the tuxies or leaf sheaths fed into the machine. Considering FIGS. 1 and 2 it appears that the action by the

chain belt conveyors

45 and 44 and all the conveyors preceding and following, consists simply in an uninterrupted forward travel such that the material is carried all the way through with a firm hold. However, within the uninterrupted and unidirectional travel mentioned, there actually occurs a reversal of stripping action on the unstripped portion of the leaf sheaths with respect to the stripper elements initially through stripper element set 65 and finally through stripper element 74.

The reversal of the stripping action is mainly caused by the relative positions of the conveyors as they pull the leaf sheaths through the stripper elements. Furthermore the swerving of the posterior ends of the stripper element sets to either the left or to the right, makes it possible to strip the tuxies or'leaf sheaths'by pulling them to the right or to the left past the corresponding stripping element unit concerned so as to thereby obtain exactly the same action effected of hand or spindle machine stripping i.e., first in one direction and then in the reverse direction. Since the tuxies are in the posterior leg 78 of the stripper element set 74, where the blade has exactly the same section features of a stripping knife such as is used in hand stripping, the remaining unstripped lengths of the tuxies must be stripped while being pulled towards the left past the final stripper element set 74, with sufficiently large towing force behind the grip pull conveyor sets made up of successively

lower conveyors

45, 47, 49 and 51 with

top conveyor counterparts

44, 46, 48 and 50, to take care of all leaf sheaths simultaneously being stripped. This is shown in FIGS. 1, 2 and 4, with side elevations appearing in FIGS. 3 and 5, details of the conveyors being portrayed in FIGS. 6, 7, 8 and 9, l0 and 11, 12 and l3, l4 and 15 and 16 and 17 not to mention the detail illustrations depicting stripper element sets portrayed in FIGS. 24, 25 and 26 as well as in FIGS. 27, 28 and 29.

The stripping process as described above is exactly the same as that of hand stripping Manila hemp or abaca, particularly in the initial stages when the process is performed upon the root end butts or portions of the leaf sheaths. The difference between this novel method and the old conventional system is that the present invention is capable of handling a much greater number of leaf sheaths. Relying upon the abundance of power available for driving the present invention and its automatic elements, particularly in the case of the arrangement detailed in FIG. I which is designed for the production of the highest quality Manila fiber, it is estimated that no less than a hundred fold advantage would be obtainable by the use of the present invention as contrasted to existing methods of stripping fibers.

The sap secreted by the leaf sheaths of the plant reacts with the plain high carbon steel cut of which the stripping blades are made. Under present practice the sap squeezed out of the leaf sheaths turns into a viscous black liquid which can contaminate and stain the resulting fibers, thereby decreasing their commercial grade.

For this reason, and because of the possibility of utilization of the by-products recoverable from stripping, it is better to replace the conventional high carbon, or tool steel blades with either stainless steel blades or a non-ferrous alloy blade which is capable of being hardened and tempered or with blades made out of some other material such as porcelain or glass which do not possess the property of reacting with the sap of the abaca plant.

It is to be understood that each of the above-described ele ments, or two or more together, may also find a useful application in other types of stripping machines which differ from the type described above.

While the invention has been illustrated and described as embodied in this stripping machine it is not intended to be limited to the details shown, since various modifications and structural changes may be made without departing in any way from the spirit of the present invention.

Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can by applying current knowledge readily adapt it for various applications without omitting features that, from the standpointof prior act, fairly constitute essential characteristics of the generic or specific aspects of this invention.

What is claimed as new and desired to be protected by Letters Patent is set forth in the appended claims:

1. Apparatus for defibering sheaths of fibrous material, particularly sheaths of abaca, comprising a plurality of elongated conveyor means each comprising an upper and a lower endless conveyor having adjacent runs for positively engaging opposite surface portions of sheaths therebetween for transporting successive sheaths sideways along a predetermined path, said plurality of conveyor means comprising at least two conveyor means aligned in longitudinal direction and spaced from each other in that direction so as to provide a gap between the trailing end of one of said two conveyor means and the leading end of the other of said two conveyor means, and a third conveyor means extending substantially parallel to said two conveyor means laterally spaced therefrom and having a leading end upstream of said gap and a trailing end downstream of said gap but upstream of the trailing end of said other conveyor means; and a pair of stripping means each comprising a stationary stripping blade having an edge and extending with at least one portion thereof transverse to the direction of said path and pressing means for pressing said sheaths during the travel thereof along said path against said edge so as to strip pulpy material from the fibrous material of the sheath, the edge portion of one of said stripping means being located in said gap and the edge portion of the other stripping means being located closely adjacent and downstream of the trailing end of said third conveyor means.

2. An apparatus as defined in claim 1, wherein each of said upper and lower conveyors includes a plurality of bundles of flexible cords arranged parallel to said path of travel, and imparting to said surfaces an undulate contour, the surfaces of said upper conveyor being complementary to the surfaces of said lower conveyor.

3. Apparatus as defined in claim 1, and including drive means connected to said plurality of conveyor means for simultaneously moving said runs of said upper and lower endless conveyors in longitudinal direction of said path.

4. Apparatus as defined in claim 1, wherein each of said stripping blades has a leading portion extending substantially in the direction of said path, whereas said portion extending transverse to the direction of said path forms a trailing portion of each blade.

5. Apparatus as defined in claim 4, wherein the trailing portion of the blade of one of said stripping means extends to one side of its leading portion, whereas the trailing portion of the blade of the other of said stripping means extends to the other side of its leading portion.

6. An apparatus as defined in claim 4, wherein each of said trailing portions includes an obtuse angle with the respective leading portion.

7. An apparatus as defined in claim 4, wherein said trailing portion is curved in a direction transverse to said leading portion.

8. An apparatus as defined in claim 4, wherein said pressing means comprise a block for each of said stripping blades arranged for pressing the sheaths against said edges of said blades.

9. An apparatus as defined in claim 8, wherein the leading portion of each blade has a front edge curved rearwardly and upwardly toward the respective block and wherein each of said blocks has a front face curved rearwardly and downwardly towards the edge of the respective blades.