US2738552A - Device for decorticating bast fiber material - Google Patents

Description

March 20, 1956 H. J. SELLING ET AL DEVICE FOR DECORTICATING BAST FIBER MATERIAL Filed July 1, 1950 3 Sheets-Sheet l March 20, 1956 H. J. SELLING ETAL 2,738,552

DEVICE FOR DECORTICATING BAST FIBER MATERIAL 3 Sheets-Sheet 2 Filed July 1, 1950 Man}! 20, 1956 H. J. SELLING ETAL DEVICE FOR DECORTICATING BAST FIBER MATERIAL Filed July 1, 1950 I5 Sheets-Sheet 3 also United States Patent- :DEYICE: FOR DECORTICATING BAST. FIBER MATERIAL "Application July. 1, 1950, Serial No. 171,674

. Clairnsprioritflapplicatidn Netherlands July 27,1949

2"Claims.l (Cl; 19--23) Th'einvention relatesto'anapparatus for decorticating hast-fibre material; such asflax; especially flax in' an"un-. rated-condition, so-called' green flax. ""The' method followed up till now which, however, cannot-beapplied to green flax, consists chiefly in a breaking process, followed by scutching. Afew devices; working with'combs'and' slats have been proposed, some of which are destined for the working of green flax but all of them have?- the disadvantage, that much fibre-material is lost, whilsttlie loosening of the ligneousparticles isfar from complete. '3 It hasappeare'd from the-inventors researches that when decorticating long fibre'fia'x varieties as-well as short oil flax .varieties andother bast fibre plants, aconsiderably bettenseparation-with much less and even hardly any loss of useful fibre. material may be achieved if -'the stalks are subjected to a bending process proceeding in longitudinal direction, foliowed by a bending in an opposite-direction, the s'talks being supported atthe'placeoftheabending-during the- -first' bending operation. T hereby, penetration of: the-bastzlayerxby the. ligneous core and' damage to the bundles' oftfibresin the best layer are -preventedf The operation is carried out: in such manner that excessive tensileistress in: the fibres is avoided.

.zflheaobi'ect. ofitthe invention is to provideanapparatus totnarry'outithiszprocess. :i In the apparatus according to thez inventionetheiicohesion between ther-ligneous core, madetibrittle xbya preliminary dryingand .the bast layer; due toia layenof; cambium: :cells, is destroyed: and the core fractured into short particles. The process-isrcarr-ied out ininuchwa way "-thatathe:fibresz'areunotbrokenuinto shorter lengths and that the shorter fibres, which are, for instance, presentinnil flax; are not-removed. .Duringatheifirstibending'nthe: stalks are supported. il'1ISl1Ch. a manner. that. the woody coreswhich rcannot :follow the? bending ofithea bast fibrerlayen mmaccount: of: its :greater: rigidity; is. forced] to buckle and toremain within; the fibrensheatht; .aThescore iSftllQWz'ibfillt'i son-that thezoutside-isiunden*tensile; strength whilstrinrthe; part-szlyingamorei inwards:compressivtrstresses occurrz'w By buckling is iheretnnderstood. theihutting action in. thezparts' of the corerunderzstrain: of pressure,.;.the'ten=. sile stress causing hardly a fracturez'or; norfracture. at tall. Imtthisntvayuhe cohesion-tbetweenvthe best-layer. andthe ligneous core is :lost: for, the; greaterpart, some; cohesion, howevenimay remain in thexbuckled. core whilstzthezrigidity' of. the core: has; disappeared at athe samettime. Imthe consecutive: bending. in; an opposite direction the: cohesion withimthe. core.v is. locally destroyed, so that-:the: coreiparticlestobtainedin :thlSrWayIgCOme to-lie loosely withimthe bast.strandwawhich;v int-thermean-time, have formed: in theshastslayem The broken and-.loosened ligneous par. tielesi"-can.-thereupons be removed in any suitable. way: with-. outtanyztdamage to the-fibres The object :Of-thisinvention is t oxprovide. anrapparatus to carry.-. out the. i-treatrnent describedabovetu Another object of zithflr invention is to: provide an apparatusr to decorticate bastfibre material insuch away that. no,.undue tensile. stresses; menu in the fibres, preventing. thereby 2,738,552 Patented Mar. 20, 1956 2 breakage of fibres and allowing an accordingly ahiglrout put "of" high-'grade fibress'" 'The material to: be treated must obviouslymbe 'broughti to a suitable" degree of: humidity; e. J g. :by drying followed, it necessary, by conditioning I Thesapparatus-according: to: the invention comprises operating -units, :-each consisting? of a: beating knife-wand one or more'stripping knives,- said r beating. :kniveseand said strippingknife. or knives having rounded working edgestandizbeingrlocated on .both sides' ot the. planet in which :the fibre :materialwhas been spread .and-zbeing able towatryaouhuwith: respect. to each other; suchapeniodical, relative movement; substantially perpendicularly. to: said plane, that they-"overlap:eachr::othen;.during theiworking stroke, one: or. moreknivessheing provided-.withmembers enabling the'zknife fiankszto deflect sideways; substantially perpendicularly: to the. direction:' of thestroke.

Accordingzt 'the:inventiona-thesevmemhers-xmay be spn'ng's;; but it iszalsozpossible to. maketherstripping knives and/hr; qthe-c beating-:tknives: partlyror-rentirel-y: resilient: so as:-to;permit1deflection of theglateralgfaces thereof. 1'"; Inorder'to; control. thectensilerstresses: occurring, in.1the

fibres; during; theetreatment" it is: furthermore possible; to

render the resilience of thesaidi resilient;.memheraadjusti able.

Alli the same; time the:invention.comprises: -means;.to maketeach-rworking unitrtreat; in" caseof IWOJQI'SrlTlOl'C working unitsibeing simultaneously used, alengthjofistem per stroke which is zonly. determined 'by. .thebeating: depth; These Il'lfi3-11S1'JI13Y; consist-in-v accumulatingknives, driven with-the samev-frequencyt-as tires-beating knives-but, ad.- vancing Qnthe latter; and-lying-onaeither side. of the wotke ing units,-the.zarrangement-and movement of saidaknives being such that they draw between the workings-units a certain length: ofistalk,:whilst furthermore, the: possibility existszto. apply. resilient 1 members to drive the. accumulating knives.

, -The,principleofithemethod according to the invention will benearerelucidated with reference to.,-the drawings in...which,;.moreover, some embodiments of parts,-. es,sential. toflthe, execution ofthe. method are: shown/diagrammaticallyaasrwell asa; decorticating machine, provided withav device accordingto the invention.

. Figs.- 1-4.showethe;.units.diagrammatically. inuvarious working; positions in aicrQss-section perpendicular to the plane in which .the,:sta.lks..are, spread.

. Figs. 5, .fis-and. show-in an enlarged cross-sectiondiagrammatically .the:principle. of the, method.v

* which. the; stripping. knives. oftwo different operatingnnits are connected inrcoupleswith the-same springs.

Eig..13. shows a-crossesection oftwooperating units with resilientlymounted accumulating knives.

In; Eigs...1-4.- thereference. numeral 1 represents one ofithemstalks to. betreated which ismoved in a suitable but; not. in. anyoparticular; way .in a direction substantiallyperpendicular. to theplane of the drawing. .Inthe embodiment. shown, themovement. of the stalks is caused by a couple of endless conveyor belts 2 and 3,between 1 which the. stalks. 1.,are, .clamped during thetransport through the operating: units. A beating knife 4 ,forms witha. pairof stripping;.,knives 5 and, 6 anoperatingor working nnithMOneither-side of,-the working ,unitsthe gatheringknives 7 are...arranged. Anupward and dQW-Ih ward. .movement .isin.v ansuitable way-communicated. to

' ligneous tube 9.

ensues keyed to the shaft and respectively connected to each of the beating knives by connecting rods 43 and pins 44. Similar eccentrics 42' keyed to the shaft 41 are provided for each of the gathering knives which are connected to each of the gathering knives by connecting rods 43 and pins 44'. Only two eccentrics 42 and only one of the eccentrics 42' are shown in the drawings, but it is understood that each of the beating knives and each of the gathering knives is provided with an eccentric and the necessary connecting members. The eccentrics 42 and 42' are respectively keyed to the shaft 41 as clearly indicated in the drawing in such a way that the beating knives and the gathering knives will reciprocate, respectively, in opposite direction upon rotation of the shaft 41. The eccentricity of the eccentrics 42 and 42' may be the same or different, depending on the stroke respectively desired for the beating or gathering knives.

Fig. 1 shows the moment that the still untreated stalk has just reached the working units. Beating knives 4 and accumulating knives 7 are situated above the plane in which the stalks are spread and stalk 1 is therefore lying free and is supported by stripping knives 5, 6.

Fig. 2 shows a consecutive position of treatment. Accumulating knives 7, which just as the beating knives 4 execute a forced movement, are here in a lower position and have drawn a certain length of the stalk between the working units.

Fig. 3 shows the moment at which the beating knives 4 in their downward movement just touch the stalk 1 to be treated. At this moment the direction in which the accumulating knives 7 are moving is already reversed and therefore they are no longer in their lowest position.

When the treatment proceeds, Fig. 4, the beating knives are moving still further downwards, whereas the accumulating knives 7 go upwards. At the downward movement of the beating knives 4 the stalk is clamped between the fianks of the beating knife 4 and the stripping knives 5, 6 which now move sideways, and the length of stalk previously drawn between the working units by the accumulating knives 7, is drawn between the stripping knives 5, 6 without subjecting the stalk to tension. The stripping knives 5, 6 move sideways, exerting a certain pressure on the stalks in a direction perpendicular to the flanks of the beating knives.

After the beating knives have reached their lowest position, their direction of movement in reversed and they arrive again in the position of Fig. 1, upon which the cycle of treatments repeats itself.

The working units are arranged with respect to the conveying device in such a way that the whole length of the stalk is successively subjected to the said treatment.

It is possible to aid the transport of the stalks by having the knives execute a movement having a component in the direction in which the stalks are moving.

Fig. shows the principle of the method. In this figure a stalk is shown during the treatment by beating and stripping knives. The stalk 1 is composed of the bast layer 8 in which the fibre bundles are lying and of the In the core of this ligneous tube is the pith cavity 10'.

' The stalk is supported by stripping knife 5 and, at the downward movement of the beating knife 4, is moving in the direction of the beating knife. The woody core 9, which has a much greater rigidity than the bast layer 8, would keep moving in its longitudinal direction as indicated in broken lines at 12but'for the presence of the 4 flank of the beating knife 11 and would, but for this knife, break through the bast layer, thus damaging the fibres.

The lateral face of the knife 11, however, forces the stem to bend together with the woody core 9, which is buckled in the process. The bending of the stem around the stripping knife 5 and the resilient lateral pressure exerted by said knife and the beating knife 11 thereupon cause the stems to flatten and the woody core to split lengthwise.

In Fig. 6 a cross-section of a stem is shown in the process of flattening, and in Fig. 7 this cross-section is shown after the stem has been pinched between the knives 5 and 11. The stem is entirely flattened and the bast layer 8 is separated lengthwise in the parts 15 and 17 while core 16 is flattened and broken. The buckling of the woody core 9 causes fractures as indicated by the numerals 13 in Fig. 5. This destroys the rigidity of the core, but does not separate it into short particles. At the consecutive bending in the opposite direction the cohesion is broken locally at 19 at the circumference 18 of the beating knife 4. The ligneous particles 20 produced in this way are now lying completely loose and may be removed in a suitable manner without fear for damage.

Fig. 8 shows an embodiment of a resilient beating knife. The heating knife is provided with a plate spring 21 connected thereto. When using such knives the stripping knives may be rigid since the spring 21 provides resilient knife flanks which are capable of yielding in a direction substantially perpendicular to the direction of the beating movement of the knives.

The stripping knives 5 and 6 shown in Fig. 9 are connected to levers 23 and 24, rotatable around an axis 22 at the ends of which levers draw springs 25 and 26 engage. Stops 27 and 28 limit the stroke of the levers in one direction, so that between the knives 5 and 6 there is always sufficient room to enable the beating knife to enter. Of course it is possible to control the force with which the knives 5 and 6 press against the stem, e. g. by rendering the end 29 of the springs 25 and 26 adjustable in and upand downward direction.

Fig. 10 shows the arrangement of a couple of stripping knives 5 and 6, rigidly fixed to a U-shaped leaf spring 30. The channel formed by the spring 30, is substantially closed, and may be advantageously connected to an exhauster for the removal of the ligneous particles or chaffs which, are separated from the stalks and fall into said channel.

Fig. 11 shows another embodiment of the stripping knives.

The stripping knives consist here of two separate and fixedly arranged plate springs 31 and 32 of a suitable shape. By rendering stops 33 and 34 adjustable in an upand downward direction the possibility to control the force of compression on the stalk is created.

Fig. 12 shows an embodiment in which the stripping knives of two adjoining working units are driven in twos by the compression springs 35. The stripping knives are mounted to oscillate about axes 36 and 37, whilst stops 39 and 38 limit the stroke.

Fig. 13 shows a modified arrangement of the accumulating knives. Instead of being driven by a suitable mechanism to carry out a reciprocating movement, these knives 7 are now mounted on suitable compression springs 40, the upper ends whereof are secured to non-moving suitable supports, which e. g. may be a part of the apparatus-frame. The length of the stroke and the resilience of the springs 40 are chosen in such a way, that the lower ends of the accumulating knives 7 are situated, as shown in Fig. 13, below the tops of the stripping knives 5 and 6, drawing thereby a certain length of the material to be treated between the work units. When the beating knives 4 penetrate in their downward movement between the stripping knives 5 and 6, the material treatedwill be drawn between said knives 5 and 6, the accumulating knives will be'pushed in upward direction by the'tension in thestalks of the material, situated between the work units, and the springs 40 will be compressed. The elasticity of these springs is such, that this upward movement of the accumulating knives can be carried out without undesired stresses occurring in the material treated. Another possibility is to connect the upper ends of the springs 40 not to a non-moving part of the apparatus, as shown in the drawing, but to a part, carrying out a reciprocating movement perpendicularly to the plane, wherein the material to be treated is spread out.

It may be of advantage to have only one or more than two stripping knives cooperate with one beating knife. In the first case the beating knives are working at one side only; in the second case the stripping knives are subdivided in their longitudinal direction, thus restricting the possibility that some stalks are too much and othersare not subjected to the compressive forces of the stripping knives.

It is evident that where in this description the word movements" is used, such as those of the beating knives and the stripping knives, always relative movements are meant and that e. g. the same effect may be achieved with non-moving stripping knives and moving beating knives as with non-moving beating knives and moving stripping knives.

In the latter case, the springs carrying at one end the gathering knives will have to be secured at their other ends either to stationary supports, which may, for instance, be a part of the apparatus frame, or of the stripping knives.

What we claim is:

1. In an apparatus for decorticating bast fiber material, an operating unit comprising in combination, at least one elongated flat beater element having a rounded working edge; at least one elongated flat stripping element having a rounded working edge extending substantially parallel to said working edge of said beater element, one of said elements being reciprocably movable relative to the other element in a plane parallel to the plane in which said said elements so as to cause resilient engagement between beater element, one of said elements being reciprocably movable relative to the other element in a plane parallel to the plane in which said other element is located from a spaced position to an overlapping position in which opposite lateral faces of said element partly overlap, resilient means associated with at least one of said elements and adapted to cause resilient engagement of said elements in said overlapping position thereof; a flat elongated reciprocable gathering member located intermediate said two operating units and adapted to engage while moving in one direction fiber material extending between said two working units and to gather a predetermined length of fiber material between said operating units when said elements of the same are in spaced position, and adapted to release said fiber material when said elements are in said overlapping position; and drive means for reciprocating at least one of said elements in each of said operating units, and for reciprocating said gathering member at the same frequency and in opposite direction to the reciprocating movement of said one of said elements 'of each of said operating units.

References Cited in the file of this patent UNITED STATES PATENTS 1,043,575 Einstein Nov. 5, 1912 1,213,750 Crain Jan. 23, 1917 1,950,403 Grant Mar. 13, 1934 2,116,997 DeLape May 10, 1938 2,130,352 Lowry Sept. 20, 1938 2,355,999 Patterson Aug. 15, 1944 2,412,445 Delegard et al Dec. 10, l946 FOREIGN PATENTS 7,204 Great Britain l836 535,060 Great Britain Mar. 27, 1951

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