CA1041282A - Non-woven tubing and production thereof - Google Patents
Non-woven tubing and production thereofInfo
- Publication number
- CA1041282A CA1041282A CA266,133A CA266133A CA1041282A CA 1041282 A CA1041282 A CA 1041282A CA 266133 A CA266133 A CA 266133A CA 1041282 A CA1041282 A CA 1041282A
- Authority
- CA
- Canada
- Prior art keywords
- turns
- tubing
- needled
- mandrel
- woven
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- D—TEXTILES; PAPER
- D04—BRAIDING; LACE-MAKING; KNITTING; TRIMMINGS; NON-WOVEN FABRICS
- D04H—MAKING TEXTILE FABRICS, e.g. FROM FIBRES OR FILAMENTARY MATERIAL; FABRICS MADE BY SUCH PROCESSES OR APPARATUS, e.g. FELTS, NON-WOVEN FABRICS; COTTON-WOOL; WADDING ; NON-WOVEN FABRICS FROM STAPLE FIBRES, FILAMENTS OR YARNS, BONDED WITH AT LEAST ONE WEB-LIKE MATERIAL DURING THEIR CONSOLIDATION
- D04H18/00—Needling machines
- D04H18/02—Needling machines with needles
Landscapes
- Engineering & Computer Science (AREA)
- Textile Engineering (AREA)
- Nonwoven Fabrics (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
A method for continuously producing needled, non-woven tubing by winding a web on a stationary mandrel, multi-needling overlying turns and frictionally driving the formed tube about the periphery of the mandrel. The mandrel is tapered to accomodate shrinkage of the tube and to assist ejection of the formed tube without application of longitudinal tension on the formed tube. The mandrel preferably includes a helical surface for progressively ejecting the rotating tubing from the static mandrel. The tube product may be formed with diameters as low as 4 mm and walls as thin as 0.5 mm and is radially compressed immediately after needling.
A method for continuously producing needled, non-woven tubing by winding a web on a stationary mandrel, multi-needling overlying turns and frictionally driving the formed tube about the periphery of the mandrel. The mandrel is tapered to accomodate shrinkage of the tube and to assist ejection of the formed tube without application of longitudinal tension on the formed tube. The mandrel preferably includes a helical surface for progressively ejecting the rotating tubing from the static mandrel. The tube product may be formed with diameters as low as 4 mm and walls as thin as 0.5 mm and is radially compressed immediately after needling.
Description
Background of the Invention The present invention relates to the production of ; needled, non-woven tubings and is concerned, more particularly, with the continuous production of such tubings with lowered weight per unit wall area and, with the capability of producing such tubings of minimal diameter and reduced weight per unit of wall area of the tubing.
~ Brief Discussion of the Prior Art 1~:
A variety of attempts have been made in the production ~ 10 of tubular textiles having structural properties suitable for '~; industrial and surgical services such as industrial filtering or de-watering and as vascular prostheses.
Earlier attempts involved the use of woven or knitted ;~i media, either installed as a sleeve about heterogeneous structure ~,~ ` or as a tubular extension between terminal portions of ducts or ' ~ fittings. However, the permeability of the textile tube is an i~ important, sometimes critical, factor in the success of the tubes ! in these services. Furthermore the uniformity of the desired permeability, throughout the length and full surface area of the ~ ,~
~ 20 tube, is~especially important in many such services.
.
Where variations in permeability are encountered there occurs a corresponding variation in fluid flow and a consequent disruption of the uniformity of the operation.
. ~
i: , ~
.
_ . ...
Z~Z
Where the structural properties of the tube are relied upon during its service and such variations in permeability are 3 present, there occurs a corresponding structural weakness in the areas of excess permeability. Such weakness subsequently may cause distension or even rupture of the tube wall.
Prior attempts in improving the permeability of such tubes and control of the uniformity of the tube during its production have involved inclusions in the fabric, such as stray i ~ fibers, velouxed webs, or flocking of the web and, tufting or looping of the exterior portion or faces of the web.
::s~
However, the more recent and more successful approaches t have been predicated upon the use of non-woven, non-knitted webs of material strands, usually reerred to as felted webs. These "felted" material tubes have afforded many advantages over the woven- or knitted-material sleeves.
s An especially effective and advantageous tubing of i needled, non-woven fabric is disclosed in my U.S. Patent 3,530,557 issued September 29, 1970.
~ While these tubes of non-woven fabric are in demand and u 20 of distinct advantage in industrial applications as filter media, roller sleeves, and the like, the most exacting requirements to be met thereby are in the field of surgery, , I , ..
- l!
4~2~z in which human life is directly dependent upon the several qualities of the tubing.
Therefore, it ;s appropriate to detail these re-quirements and the reasons therefor~, it being apparent to those skilled in the art that the tubings exhibiting successul ~ ¦
accomodation of these surgical requirements will provide - ~ ' comparable advantages in the other, industrial services ¦
-~ Tn service as~vascular prosthe~is, the precise ' ' ' ' ~ o fe, :
pèrmeabilit~ and a uniformity thereof are an ~bffe~e necessity.
; The permeability requirements appear to be self- :
contradictory~in this service, since the ~unction o~ the tubular prosthesis is that o replacing diseased or damaged ¦~vascuLar sections and3 accordingly, serving as a conduit for blood between healthy or undamaged vascular sections. In service~ there~ore, the tubing necessarily is to be substa~- ~ I
Lially impervious to blood and ies constituents. :. : ~;¦
Uowever, in order to achieve adequate healing at ¦ i the suture~points an~ tissue:generation along the prosthe~is, ~ ~ ¦
it is necessary that the wall structure of the tubing be I ~ i permeable to permit radial.migration o~ cellular matter to enable tissue migration radially into the tubing to form a :
"li.~e" vascular member encasing, and structurally supported by, the tubular prosthesis The pre~erred solution to these apparently contra~
dictory requirements has been that of pro~iding permeable ' tubing which is made initially i~permeable, before installation~
I i l~
- I! , .
4~;~8Z
by a pre-clotting step which closes the interstices o the '. tubular wall sufficiently to make the t.ubing impermeable when : ` installed. Eventually, the clotted matter is to be replaced `
1; I by celluLar întrusion through the tube-wall interstices, and absorption of the clotted material.
Howe~er, the presence of the pre-clotted matter makes such prosthesis potentially hlghly-thrombogenic. Ac- : ', cordingly, it is imperative that the structure of the tubing ; !:pro~lde for secure adhesion and.retention of all such clot.ted matter, in order to avOid release and a consequent thrombus I ~ downstream of the prosthesi5 This requirement of providing optimal surfaces for . I ~adherence¦~f.clotted matter also serves to the advantage of ¦~the:subsequent progression:of. new tissue into and through the ~all~of~the tubing.~ Accordingly, the interstitial and sur- -~face:characteristics are ~mportant~to the succesful service i : :of the~tubing,~along with the close control o~ the permea~
: :- ~ bility. :~
¦ : The:de5ired permeability~ however, necessarily is :: ~ I to be uniform both along the length of the tubing and about ~ I
-its circumference~ Significant variations from such uni-¦~. ormity can prevent passage of desired constituents, if the ~, permeability is below the preselected level. ~here are~s of excessi~e permeability are present,e~cessive rates of constituent transfer may occur and the concomitant struc-¦ tural differences or wealcness make the tube wall prone to ' 1i ~ 5 11 ~
distension, ballooning, aneurysmal dilation or even rupture at that zone.
i The non-woven tubing of my U.S. Patent No. 3,530,557 i has proven to be quite advantageous over prior tubings, and especially so in sèrvice as a vascular prosthesis, and meets the several requirements set forth hereinbefore.
~' However, the production of the tubing required close j~ synchronization of the layer-winding speed and the tube take-up rate, especially since the tube take-up apparatus exerts a ~ 10 tension upon the tubing.
The problems encountered in the production of such tubings become even more acute when it is desired to produce relatively small tubes such as are often desired as vascular prostheses.
Prior systems have included units for winding and ~ needling a non-woven web on a mandrel which is longitudinally ¦ grooved to~provide a trough for picks which continuously move the formed tub mg parallel to the axis of the mandrel. These machines, therefore, are limited to relatively large diameter mandrels, to accomodate the withdrawing equipment, in the order-of about 40~n, the actual size depending upon the size of the slide rollers and the length of their pins.
A further limitation of such units involves the wall-strength of the finished tube, the minimum strength of which has required about 4r . This corresponds to a weight {
l i of from 350 to 400 grams per square meter of wall area A reduc~ion of these dimensions and weights has t been possible with the use of the prior discharge mecha-nisms. Consequently, the prior means of withdrawal and dis-Il .
! charge of the tubing of such installations have been costly ; 1 and imposed problems i.n the operation and versatility of the installa~ion. ' ¦~ Therefore~ prior methods and installations for i forming non-woven tubings have not been found to be entirely 1~ ¦ sa~is~actory i~ all respects.
;;: `. ! .
¦ Ob~ects of the Invention .1 ¦ ~ It is an object of the present invention to provide ¦ an~improved system for producing needled tubing of non woven ~abric.
- ~ ~ It is another object of the present invention to - l~provide an improved system for producing tubing of non~woven I abric which is wound in overlapping layers and needled at ': ~ ! - . .
multiple angles.
I It is a further object of the present invention to provide tubing of non-woven fabric which is wound in over-lapping layers on a mandrel, needled at multiple angles, and pressed against ~he mandrel by an external pressing roll.
It is yet another object of the present inventlon to ~ provide needled, non-woven tubing formed on a mandrel, the - ¦l tubing being rotated on the mandrel by external driving rolls.
f~
,......... 1l , .
il .
l~ ILZ8Z
A further object of the present invention is the provision of a needled, non-woven tubing -formed on a mandrel, the tubing being discharged from the mandrel by a helical sur~ace and relative rotation between the tubing and the helical ¦, surface - i Another object of the present invention is the pro~
vision of a needled, non-woven tubing formed on a mandrel and !i needled at multiple angles, while being pressed against the mandrel and rotated by rotating pressure rolls, and discharged rom the mandrel by its rotation agai~st a helical sur~ace on the mandrel.
A further object o the present invention is the i provision o a~needled, non-woven tubing which is formed on ; I A ~sndrel, radially compressed and then discharged from ~he mandre~.
Summar~_of the Invention - In~general, the preferred ~orm of the presen~ in ; ¦ vention comprises a tube-winding and needling station including~
. ¦~a tapered ma~drel having needle apertures in its region of ¦ larger diameter, a reciprocating bar having a plurality of needles aligned with the needle apertures, and at leas~ one dri~ing roll in pressing rel~tionship with the tubing being ) -Eormed. PreEerably, the mandrel includes a helical surface i downstream of the needle apertures and within the zone of pressure of the driving roll.
j! i , Z8;~
The present invention is capable of continuously producing high quality non-woven tubing in diameters down to 4 or 5 mm and with reduced weight per unit of wall area. This ;.
can be accomplished without the requirement of special pre-paration equipment 9 such as carding installations, with only a narrow band of thin, non~woven material being supplied directly ¦ to the winding unit. Therefore, the distortion and longitu-dinal orientation of the fibers which are typical o. the prior art can be avoided and the desired, multiple inter-engagement I
j of the fibers can be obtained, while the cost of tube-withdrawing equipment is avoided. ` ' ¦ Brie D _ cription of the Drawin ¦ ~ ~ A better understanding of the~invention and its l objects ~a~ be derived from the ollowing description and accompanying drawings, in which:
Figure 1 is a partly-schematic side elevation of a tube-forming installation embodying the~invention ¦ Figure 2 is a plan view of the i~stallation of ¦ Figure 1, and ¦ Figure 3 is a view of a portion of Figure 2, on an i enlarged~scale, with portions r~moved for clarity and showing details of the tube-forming unit.
Detailed Description of the Preferred Em~odiment As shown in the drawings~ the preferred form of tube-¦11 forming apparatus according to the invention comprises an Il ~ g -I
~
4~2~
installation including a conveyor l, a nip-roller 2, an orienting and transfer station including first and second . rolls 3 and 4, respectively, and a conveyor 5 for delivering the pressed web to a needling and tube-forming machine 6.
i The web received on the conveyor 1 may be a com-mercial web, as rece;ved, or may be subjected to a pre-carding~ i step if desired. The web typically comprises ibers which : I æ e felted with their lengths oriented generally longitudinally ! o~ the web and in generally parallel relationship.
¦ The material of the web may be a textile, metal or : mineral fibers or ilaments, or a mixture thereof. The fibers S
;~ . or filaments are to be very thin. a~d flexible. ~ ¦
The tube-forming unit 6 includes a sta~ionary mandrel ~i ha~ing~a plurality o needle apertura 8 for receiving re- i ciprocating needles 9 of a needling head 10. The mandrel 7 tapers toward a discharge.end remote from the needling zone ~ j i and includes a helical section 11 : ~ :. : ~ The helical section preferably is formed with saw~
: ~ toothed flights 12 which indi~idually taper outwardly to an apex 13 at their trailing or downstream edge The flights 1~ ¦
progre5sively~enlarge in diameter towaxd the center or an . ¦
¦~ intermediate ~one of the helix and again reduce in diameter toward the discharge end. The axis of the helical section is ~ coaxial with the axis of the mandrel and the tubing il Flanking the stationary mandrel, a pair of drive I rolls 14 and 14' are mounted substantial:Ly diametrically l ¦
¦! i ~L~4~ i32 opposite each other on hinged yokes 15, 15' which are adjustably biased by means of compression springs 16, 16' and lever arms to rock inwardly to press the rollers 14, 14' inwardly toward the mandrel.
The rollers 14, 14' preferably are parallel to the tapered mandrel surface and are covered with rubber or another material suitable for providing a driving friction against a tube in position on the mandrel. The amount of pressure with ' which the rollers bear against the tube may be adjusted by means of threaded hand wheels 17, 17'. The rollers are driven by suitable variable-speed drive means, not shown, via universal joints 18 and 18'.
The needling head 10 is driven by conventional means and has associated therewith a stripper or foot member 19 which is curved to conform to the material contour in the needling zone to prevent lifting of the needled material by retraction ,~ of the needles. The needles are barbed, with the wide portion ~i ~ of the barbs facing the penetrating point to catch fibers and to draw the fibers inwardly through underlying layers of the windlngs.
I The needling procedure is as disclosed in my afore-¦ mentioned U.S. Patent No. 3,530,557 and the tube product is therefore needled by a plurality of needles at differing angles with respect to the radius of the tubing.
The several conveyors 1 and 5 and rolls 2, 3 and 4 ~¦~ preferably are all driven by variable-speed drives to provide !
:, .
A, - 11 , I ' 1 Il .
a precise rate o-f feed of the sliver or web to the tube forming . uni~. In order to stabilize this critical supply factor and to initiate a ~ee~eab~e transverse re-orientation of the fibers, il it is preferable to draw the web thr~ugh the nip rolls 2 at , a linear speed slightly in ~cess of the speed of the belt ,.lZ
' conveyor 1 ; deposit the web in thinned form on the surface .
' of the roll 3 by rotating the roll at a peripheral speed considerably higher than the linear speed through the nip , rollsj~ and coliect thc web in a partially-jumbled condition~
with its fibers partiall~ transversely-reoriented, on Il ¦ the roll 4, which is rotated at a much lower peripheral speed I i ¦ than the roll 3. This initial :Eiber reorientation is en~
,: , hanced if the rolls 3 and 4 are provided with tractive surfaces, such as metallic card cloth, and a stripping comb 2~: is ~ positioned adjacent the conveyor 5 to:strip the sliver or ~web~from the roll 4.
:~ The speed of the conveyor 5 is then matched~to : ~ ~
suppl~ the web to the~drive~roll 14 at the;desired rate.: - ,`
O eration of the Preferred Embodimen~ 1:
In operation, a suitably-prepared, extremely thin ¦¦ sliver or web o~ material is supplied to the roll 14 and passes ¦I t~erearound to wind on the ma~drel and subsequently is needled Il at multiple angles to form the non-woven tubing. Each needle penetration drives fibers from the outer layers angularly into the subjacent layers, thereby firmly securing and in-terlocking the windings into a continuous tubing 1~34~2 i The continuous tubing thus produced is driven around ~he statîonary mandrel by the drive rolls 14 and 14' and, as a result of the presence of the helix 11 against which it /S
i~ pressed, continuously ejects itself or literally screws itself ¦, off the stationary mandrel.
This self-ejecting efEert is actually enhanced by the shrinkage tendency of the tubing, w~en it is so needled~ The i shrinka~e, the taper of the mandrel and the enlargement o the helix thus cooperate in the ejection of the tubing, instead of the shrinkage being effective to oppose removal of the tubing, thereby requiring tensioning stresses to be imposed ~or with-drawal.
In dit~ect contrast to longitudinal-stretching or hdrawal of~tubing, the tubing formed in accordance with the ¦~present invention is actually compressed radially on the helix ¦ and~is~, therefore, pressed off the mandrel without longitudinal distortions.
~ The actual taper of the mandrel will depend upo~ ~he type o~ iber and its shrinkage tendency upon needling, and may be in the order of 1.5 to 2 taper.
Preferab~y, the helix is formed as a threadably- j ! interchangeable component of the mandrel, so that helices o I ~ di~fering pitches may be employed. i Variation of the ejection rate of the tubing may be !
; accomplished by the use of dif~erent helices and by adjustment ¦l, of the speed of the drive rollers, thereby modiEying the wall ~! thickness o the tubLng, ~or a given rate o~ web intake.
! ' `, . . .
'~ ~f~i4~82 It should be noted that the supply o:E the incoming ; web over the surface of the drive roller 14 is especially ad-..vantageous. The resultant flattening or pressing o the web between the drive roller 14 and the mandrel 7 thus orients '~
,and de-lofts the web prior to the needling step. This pre~
.ferably,is augmented by~positioning the final conveyor 5 in almost tangent relationship to~the roller 14.
Therefore~ it is apparent that the present invention ', ,provides a unique method and apparatus for producing non-woven tubings and a new fo~m of tubing which is subjected to radial compression immediately after its formation.
. The radial compression of the tube wall not only ¦forms a relatively thin wall~ but also has a densifying effeci~ -which~tends to~reduce the initial permeability of the.structure . `
i without permanently.altering the~permeability or weakening the wall~structure, as may Dccur when such tubing is subjected ta su~stan~ial longitudinal ~tensions.
The continuous, uniform~ejection of the tubing as it :: is formed provides for a uniform o~erlapping and stitch-locking t, of the~turns, which is of extreme importan~e i~ very thin-walled, I
: ,small~diameter tubing and oE great advantage in tubing o larger ~ ¦
: Idimenstons.
'~, Although dif~erent shapes or flight-profiles may be , e,77,0/~
¦ ~ it has been found that the sawtooth profile disclosed , ,provides a particularly accurate and uniform ejection of the ,tubing, I
14 - j --3 C~ ,Z~
` Tubing produced .in accordance with the present invention has been particularly effective in surgical service as vascular prostheses, not only by reason of the advantages attributable to non-woven tubing, but also as a' consequence of the reliability which`is achieved in small-diameter tubings of very small wall-thickness. Tubings have been produced in the range of from 4 to 30 millimeters and with wall thicknesses as low as 0~5mm. It is to be understood, however, that the advantages deriveable from the present invention are also appropriate to tubings of diameters larger than 30mm.
Furthermore, although the present invention has been disclosed and discussed with particular regard to its exceptional advantages in terms of vascular prostheses, it is to be under-stood that the tubing of the present invention may be employed in 1, ~, several industrial services including tanneries, paper mills and ~ as filtering or dewatering surfaces.
:1 ~ ' . ~
,.
-.' '' ~' .
.: .
. ~ .
~ Brief Discussion of the Prior Art 1~:
A variety of attempts have been made in the production ~ 10 of tubular textiles having structural properties suitable for '~; industrial and surgical services such as industrial filtering or de-watering and as vascular prostheses.
Earlier attempts involved the use of woven or knitted ;~i media, either installed as a sleeve about heterogeneous structure ~,~ ` or as a tubular extension between terminal portions of ducts or ' ~ fittings. However, the permeability of the textile tube is an i~ important, sometimes critical, factor in the success of the tubes ! in these services. Furthermore the uniformity of the desired permeability, throughout the length and full surface area of the ~ ,~
~ 20 tube, is~especially important in many such services.
.
Where variations in permeability are encountered there occurs a corresponding variation in fluid flow and a consequent disruption of the uniformity of the operation.
. ~
i: , ~
.
_ . ...
Z~Z
Where the structural properties of the tube are relied upon during its service and such variations in permeability are 3 present, there occurs a corresponding structural weakness in the areas of excess permeability. Such weakness subsequently may cause distension or even rupture of the tube wall.
Prior attempts in improving the permeability of such tubes and control of the uniformity of the tube during its production have involved inclusions in the fabric, such as stray i ~ fibers, velouxed webs, or flocking of the web and, tufting or looping of the exterior portion or faces of the web.
::s~
However, the more recent and more successful approaches t have been predicated upon the use of non-woven, non-knitted webs of material strands, usually reerred to as felted webs. These "felted" material tubes have afforded many advantages over the woven- or knitted-material sleeves.
s An especially effective and advantageous tubing of i needled, non-woven fabric is disclosed in my U.S. Patent 3,530,557 issued September 29, 1970.
~ While these tubes of non-woven fabric are in demand and u 20 of distinct advantage in industrial applications as filter media, roller sleeves, and the like, the most exacting requirements to be met thereby are in the field of surgery, , I , ..
- l!
4~2~z in which human life is directly dependent upon the several qualities of the tubing.
Therefore, it ;s appropriate to detail these re-quirements and the reasons therefor~, it being apparent to those skilled in the art that the tubings exhibiting successul ~ ¦
accomodation of these surgical requirements will provide - ~ ' comparable advantages in the other, industrial services ¦
-~ Tn service as~vascular prosthe~is, the precise ' ' ' ' ~ o fe, :
pèrmeabilit~ and a uniformity thereof are an ~bffe~e necessity.
; The permeability requirements appear to be self- :
contradictory~in this service, since the ~unction o~ the tubular prosthesis is that o replacing diseased or damaged ¦~vascuLar sections and3 accordingly, serving as a conduit for blood between healthy or undamaged vascular sections. In service~ there~ore, the tubing necessarily is to be substa~- ~ I
Lially impervious to blood and ies constituents. :. : ~;¦
Uowever, in order to achieve adequate healing at ¦ i the suture~points an~ tissue:generation along the prosthe~is, ~ ~ ¦
it is necessary that the wall structure of the tubing be I ~ i permeable to permit radial.migration o~ cellular matter to enable tissue migration radially into the tubing to form a :
"li.~e" vascular member encasing, and structurally supported by, the tubular prosthesis The pre~erred solution to these apparently contra~
dictory requirements has been that of pro~iding permeable ' tubing which is made initially i~permeable, before installation~
I i l~
- I! , .
4~;~8Z
by a pre-clotting step which closes the interstices o the '. tubular wall sufficiently to make the t.ubing impermeable when : ` installed. Eventually, the clotted matter is to be replaced `
1; I by celluLar întrusion through the tube-wall interstices, and absorption of the clotted material.
Howe~er, the presence of the pre-clotted matter makes such prosthesis potentially hlghly-thrombogenic. Ac- : ', cordingly, it is imperative that the structure of the tubing ; !:pro~lde for secure adhesion and.retention of all such clot.ted matter, in order to avOid release and a consequent thrombus I ~ downstream of the prosthesi5 This requirement of providing optimal surfaces for . I ~adherence¦~f.clotted matter also serves to the advantage of ¦~the:subsequent progression:of. new tissue into and through the ~all~of~the tubing.~ Accordingly, the interstitial and sur- -~face:characteristics are ~mportant~to the succesful service i : :of the~tubing,~along with the close control o~ the permea~
: :- ~ bility. :~
¦ : The:de5ired permeability~ however, necessarily is :: ~ I to be uniform both along the length of the tubing and about ~ I
-its circumference~ Significant variations from such uni-¦~. ormity can prevent passage of desired constituents, if the ~, permeability is below the preselected level. ~here are~s of excessi~e permeability are present,e~cessive rates of constituent transfer may occur and the concomitant struc-¦ tural differences or wealcness make the tube wall prone to ' 1i ~ 5 11 ~
distension, ballooning, aneurysmal dilation or even rupture at that zone.
i The non-woven tubing of my U.S. Patent No. 3,530,557 i has proven to be quite advantageous over prior tubings, and especially so in sèrvice as a vascular prosthesis, and meets the several requirements set forth hereinbefore.
~' However, the production of the tubing required close j~ synchronization of the layer-winding speed and the tube take-up rate, especially since the tube take-up apparatus exerts a ~ 10 tension upon the tubing.
The problems encountered in the production of such tubings become even more acute when it is desired to produce relatively small tubes such as are often desired as vascular prostheses.
Prior systems have included units for winding and ~ needling a non-woven web on a mandrel which is longitudinally ¦ grooved to~provide a trough for picks which continuously move the formed tub mg parallel to the axis of the mandrel. These machines, therefore, are limited to relatively large diameter mandrels, to accomodate the withdrawing equipment, in the order-of about 40~n, the actual size depending upon the size of the slide rollers and the length of their pins.
A further limitation of such units involves the wall-strength of the finished tube, the minimum strength of which has required about 4r . This corresponds to a weight {
l i of from 350 to 400 grams per square meter of wall area A reduc~ion of these dimensions and weights has t been possible with the use of the prior discharge mecha-nisms. Consequently, the prior means of withdrawal and dis-Il .
! charge of the tubing of such installations have been costly ; 1 and imposed problems i.n the operation and versatility of the installa~ion. ' ¦~ Therefore~ prior methods and installations for i forming non-woven tubings have not been found to be entirely 1~ ¦ sa~is~actory i~ all respects.
;;: `. ! .
¦ Ob~ects of the Invention .1 ¦ ~ It is an object of the present invention to provide ¦ an~improved system for producing needled tubing of non woven ~abric.
- ~ ~ It is another object of the present invention to - l~provide an improved system for producing tubing of non~woven I abric which is wound in overlapping layers and needled at ': ~ ! - . .
multiple angles.
I It is a further object of the present invention to provide tubing of non-woven fabric which is wound in over-lapping layers on a mandrel, needled at multiple angles, and pressed against ~he mandrel by an external pressing roll.
It is yet another object of the present inventlon to ~ provide needled, non-woven tubing formed on a mandrel, the - ¦l tubing being rotated on the mandrel by external driving rolls.
f~
,......... 1l , .
il .
l~ ILZ8Z
A further object of the present invention is the provision of a needled, non-woven tubing -formed on a mandrel, the tubing being discharged from the mandrel by a helical sur~ace and relative rotation between the tubing and the helical ¦, surface - i Another object of the present invention is the pro~
vision of a needled, non-woven tubing formed on a mandrel and !i needled at multiple angles, while being pressed against the mandrel and rotated by rotating pressure rolls, and discharged rom the mandrel by its rotation agai~st a helical sur~ace on the mandrel.
A further object o the present invention is the i provision o a~needled, non-woven tubing which is formed on ; I A ~sndrel, radially compressed and then discharged from ~he mandre~.
Summar~_of the Invention - In~general, the preferred ~orm of the presen~ in ; ¦ vention comprises a tube-winding and needling station including~
. ¦~a tapered ma~drel having needle apertures in its region of ¦ larger diameter, a reciprocating bar having a plurality of needles aligned with the needle apertures, and at leas~ one dri~ing roll in pressing rel~tionship with the tubing being ) -Eormed. PreEerably, the mandrel includes a helical surface i downstream of the needle apertures and within the zone of pressure of the driving roll.
j! i , Z8;~
The present invention is capable of continuously producing high quality non-woven tubing in diameters down to 4 or 5 mm and with reduced weight per unit of wall area. This ;.
can be accomplished without the requirement of special pre-paration equipment 9 such as carding installations, with only a narrow band of thin, non~woven material being supplied directly ¦ to the winding unit. Therefore, the distortion and longitu-dinal orientation of the fibers which are typical o. the prior art can be avoided and the desired, multiple inter-engagement I
j of the fibers can be obtained, while the cost of tube-withdrawing equipment is avoided. ` ' ¦ Brie D _ cription of the Drawin ¦ ~ ~ A better understanding of the~invention and its l objects ~a~ be derived from the ollowing description and accompanying drawings, in which:
Figure 1 is a partly-schematic side elevation of a tube-forming installation embodying the~invention ¦ Figure 2 is a plan view of the i~stallation of ¦ Figure 1, and ¦ Figure 3 is a view of a portion of Figure 2, on an i enlarged~scale, with portions r~moved for clarity and showing details of the tube-forming unit.
Detailed Description of the Preferred Em~odiment As shown in the drawings~ the preferred form of tube-¦11 forming apparatus according to the invention comprises an Il ~ g -I
~
4~2~
installation including a conveyor l, a nip-roller 2, an orienting and transfer station including first and second . rolls 3 and 4, respectively, and a conveyor 5 for delivering the pressed web to a needling and tube-forming machine 6.
i The web received on the conveyor 1 may be a com-mercial web, as rece;ved, or may be subjected to a pre-carding~ i step if desired. The web typically comprises ibers which : I æ e felted with their lengths oriented generally longitudinally ! o~ the web and in generally parallel relationship.
¦ The material of the web may be a textile, metal or : mineral fibers or ilaments, or a mixture thereof. The fibers S
;~ . or filaments are to be very thin. a~d flexible. ~ ¦
The tube-forming unit 6 includes a sta~ionary mandrel ~i ha~ing~a plurality o needle apertura 8 for receiving re- i ciprocating needles 9 of a needling head 10. The mandrel 7 tapers toward a discharge.end remote from the needling zone ~ j i and includes a helical section 11 : ~ :. : ~ The helical section preferably is formed with saw~
: ~ toothed flights 12 which indi~idually taper outwardly to an apex 13 at their trailing or downstream edge The flights 1~ ¦
progre5sively~enlarge in diameter towaxd the center or an . ¦
¦~ intermediate ~one of the helix and again reduce in diameter toward the discharge end. The axis of the helical section is ~ coaxial with the axis of the mandrel and the tubing il Flanking the stationary mandrel, a pair of drive I rolls 14 and 14' are mounted substantial:Ly diametrically l ¦
¦! i ~L~4~ i32 opposite each other on hinged yokes 15, 15' which are adjustably biased by means of compression springs 16, 16' and lever arms to rock inwardly to press the rollers 14, 14' inwardly toward the mandrel.
The rollers 14, 14' preferably are parallel to the tapered mandrel surface and are covered with rubber or another material suitable for providing a driving friction against a tube in position on the mandrel. The amount of pressure with ' which the rollers bear against the tube may be adjusted by means of threaded hand wheels 17, 17'. The rollers are driven by suitable variable-speed drive means, not shown, via universal joints 18 and 18'.
The needling head 10 is driven by conventional means and has associated therewith a stripper or foot member 19 which is curved to conform to the material contour in the needling zone to prevent lifting of the needled material by retraction ,~ of the needles. The needles are barbed, with the wide portion ~i ~ of the barbs facing the penetrating point to catch fibers and to draw the fibers inwardly through underlying layers of the windlngs.
I The needling procedure is as disclosed in my afore-¦ mentioned U.S. Patent No. 3,530,557 and the tube product is therefore needled by a plurality of needles at differing angles with respect to the radius of the tubing.
The several conveyors 1 and 5 and rolls 2, 3 and 4 ~¦~ preferably are all driven by variable-speed drives to provide !
:, .
A, - 11 , I ' 1 Il .
a precise rate o-f feed of the sliver or web to the tube forming . uni~. In order to stabilize this critical supply factor and to initiate a ~ee~eab~e transverse re-orientation of the fibers, il it is preferable to draw the web thr~ugh the nip rolls 2 at , a linear speed slightly in ~cess of the speed of the belt ,.lZ
' conveyor 1 ; deposit the web in thinned form on the surface .
' of the roll 3 by rotating the roll at a peripheral speed considerably higher than the linear speed through the nip , rollsj~ and coliect thc web in a partially-jumbled condition~
with its fibers partiall~ transversely-reoriented, on Il ¦ the roll 4, which is rotated at a much lower peripheral speed I i ¦ than the roll 3. This initial :Eiber reorientation is en~
,: , hanced if the rolls 3 and 4 are provided with tractive surfaces, such as metallic card cloth, and a stripping comb 2~: is ~ positioned adjacent the conveyor 5 to:strip the sliver or ~web~from the roll 4.
:~ The speed of the conveyor 5 is then matched~to : ~ ~
suppl~ the web to the~drive~roll 14 at the;desired rate.: - ,`
O eration of the Preferred Embodimen~ 1:
In operation, a suitably-prepared, extremely thin ¦¦ sliver or web o~ material is supplied to the roll 14 and passes ¦I t~erearound to wind on the ma~drel and subsequently is needled Il at multiple angles to form the non-woven tubing. Each needle penetration drives fibers from the outer layers angularly into the subjacent layers, thereby firmly securing and in-terlocking the windings into a continuous tubing 1~34~2 i The continuous tubing thus produced is driven around ~he statîonary mandrel by the drive rolls 14 and 14' and, as a result of the presence of the helix 11 against which it /S
i~ pressed, continuously ejects itself or literally screws itself ¦, off the stationary mandrel.
This self-ejecting efEert is actually enhanced by the shrinkage tendency of the tubing, w~en it is so needled~ The i shrinka~e, the taper of the mandrel and the enlargement o the helix thus cooperate in the ejection of the tubing, instead of the shrinkage being effective to oppose removal of the tubing, thereby requiring tensioning stresses to be imposed ~or with-drawal.
In dit~ect contrast to longitudinal-stretching or hdrawal of~tubing, the tubing formed in accordance with the ¦~present invention is actually compressed radially on the helix ¦ and~is~, therefore, pressed off the mandrel without longitudinal distortions.
~ The actual taper of the mandrel will depend upo~ ~he type o~ iber and its shrinkage tendency upon needling, and may be in the order of 1.5 to 2 taper.
Preferab~y, the helix is formed as a threadably- j ! interchangeable component of the mandrel, so that helices o I ~ di~fering pitches may be employed. i Variation of the ejection rate of the tubing may be !
; accomplished by the use of dif~erent helices and by adjustment ¦l, of the speed of the drive rollers, thereby modiEying the wall ~! thickness o the tubLng, ~or a given rate o~ web intake.
! ' `, . . .
'~ ~f~i4~82 It should be noted that the supply o:E the incoming ; web over the surface of the drive roller 14 is especially ad-..vantageous. The resultant flattening or pressing o the web between the drive roller 14 and the mandrel 7 thus orients '~
,and de-lofts the web prior to the needling step. This pre~
.ferably,is augmented by~positioning the final conveyor 5 in almost tangent relationship to~the roller 14.
Therefore~ it is apparent that the present invention ', ,provides a unique method and apparatus for producing non-woven tubings and a new fo~m of tubing which is subjected to radial compression immediately after its formation.
. The radial compression of the tube wall not only ¦forms a relatively thin wall~ but also has a densifying effeci~ -which~tends to~reduce the initial permeability of the.structure . `
i without permanently.altering the~permeability or weakening the wall~structure, as may Dccur when such tubing is subjected ta su~stan~ial longitudinal ~tensions.
The continuous, uniform~ejection of the tubing as it :: is formed provides for a uniform o~erlapping and stitch-locking t, of the~turns, which is of extreme importan~e i~ very thin-walled, I
: ,small~diameter tubing and oE great advantage in tubing o larger ~ ¦
: Idimenstons.
'~, Although dif~erent shapes or flight-profiles may be , e,77,0/~
¦ ~ it has been found that the sawtooth profile disclosed , ,provides a particularly accurate and uniform ejection of the ,tubing, I
14 - j --3 C~ ,Z~
` Tubing produced .in accordance with the present invention has been particularly effective in surgical service as vascular prostheses, not only by reason of the advantages attributable to non-woven tubing, but also as a' consequence of the reliability which`is achieved in small-diameter tubings of very small wall-thickness. Tubings have been produced in the range of from 4 to 30 millimeters and with wall thicknesses as low as 0~5mm. It is to be understood, however, that the advantages deriveable from the present invention are also appropriate to tubings of diameters larger than 30mm.
Furthermore, although the present invention has been disclosed and discussed with particular regard to its exceptional advantages in terms of vascular prostheses, it is to be under-stood that the tubing of the present invention may be employed in 1, ~, several industrial services including tanneries, paper mills and ~ as filtering or dewatering surfaces.
:1 ~ ' . ~
,.
-.' '' ~' .
.: .
. ~ .
Claims (5)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. The method of making non-woven tubing comprising:
a) winding at least one non-woven web of fibers at an angle forming a helix of at least partially overlapping turns, b) needling a multiplicity of fibers from each turn transversely through at least one subjacent turn to fasten said turns to each other, c) permitting said needled turns to shrink substantially radially, d) radially compressing said needled turns, and e) continuously ejecting said needled turns from said winding step by compression thereof against a helical surface generally parallel to the direction of ejection while rotating one of said helical surface and said needled turns with respect to the other.
a) winding at least one non-woven web of fibers at an angle forming a helix of at least partially overlapping turns, b) needling a multiplicity of fibers from each turn transversely through at least one subjacent turn to fasten said turns to each other, c) permitting said needled turns to shrink substantially radially, d) radially compressing said needled turns, and e) continuously ejecting said needled turns from said winding step by compression thereof against a helical surface generally parallel to the direction of ejection while rotating one of said helical surface and said needled turns with respect to the other.
2. The method of Claim 1 in which said needled turns are rotated about a stationary mandrel.
3. The method of Claim 2 in which said needled turns are compressed radially inwardly against said helical surface on said stationary mandrel.
4. The method of Claim 2 in which said web is radially pressed against said mandrel prior to said needling step.
5. Tubing consisting of a plurality of needled co-axial overlapping turns of at least one fibrous web of non-woven fabric, a plurality of fibers integral with each turn angularly extending from said turn inwardly through at least one subjacent turn, said turns being fastened to each other by said `
angularly inwardly extendive fiber and compressed upon each other by being radially inwardly pressed upon a helix.
angularly inwardly extendive fiber and compressed upon each other by being radially inwardly pressed upon a helix.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE19752552243 DE2552243C3 (en) | 1975-11-21 | 1975-11-21 | Device for the continuous production of tubular needle punched nonwovens |
| US05/681,089 US4085486A (en) | 1968-07-01 | 1976-04-19 | Method of producing needled, non-woven tubing |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1041282A true CA1041282A (en) | 1978-10-31 |
Family
ID=25769634
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA266,133A Expired CA1041282A (en) | 1975-11-21 | 1976-11-19 | Non-woven tubing and production thereof |
Country Status (7)
| Country | Link |
|---|---|
| JP (1) | JPS6039783B2 (en) |
| CA (1) | CA1041282A (en) |
| CH (1) | CH601545A5 (en) |
| FR (1) | FR2332356A1 (en) |
| GB (1) | GB1562641A (en) |
| IT (1) | IT1067045B (en) |
| NL (1) | NL7612730A (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE2900935C2 (en) * | 1979-01-11 | 1986-10-16 | Oskar Dilo Maschinenfabrik Kg, 6930 Eberbach | Method and device for producing velor needle-punched nonwoven webs |
| FR2557550B1 (en) * | 1983-12-28 | 1986-05-30 | Europ Propulsion | METHOD AND APPARATUS FOR THE MANUFACTURE OF THREE-DIMENSIONAL REVOLUTION STRUCTURES |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3909893A (en) * | 1974-07-15 | 1975-10-07 | John Clarke Wilde | Process for making tubular needlefelted material |
-
1976
- 1976-11-16 NL NL7612730A patent/NL7612730A/en not_active Application Discontinuation
- 1976-11-18 CH CH1452176A patent/CH601545A5/xx not_active IP Right Cessation
- 1976-11-19 JP JP13854376A patent/JPS6039783B2/en not_active Expired
- 1976-11-19 GB GB4848576A patent/GB1562641A/en not_active Expired
- 1976-11-19 CA CA266,133A patent/CA1041282A/en not_active Expired
- 1976-11-19 IT IT2956976A patent/IT1067045B/en active
- 1976-11-22 FR FR7635091A patent/FR2332356A1/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| NL7612730A (en) | 1977-05-24 |
| FR2332356A1 (en) | 1977-06-17 |
| JPS52128467A (en) | 1977-10-27 |
| IT1067045B (en) | 1985-03-12 |
| JPS6039783B2 (en) | 1985-09-07 |
| GB1562641A (en) | 1980-03-12 |
| FR2332356B1 (en) | 1981-11-27 |
| CH601545A5 (en) | 1978-07-14 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| FI101062B (en) | Roll-up machine for rolling a fiber mat around itself and a so-compressed food roll | |
| FI96333B (en) | Press blanket and procedure for its preparation | |
| CA1321311C (en) | Reinforced press jacket for a press unit for the treatment of web-like material, such as paper webs, as well as process and device for its production | |
| US7500293B2 (en) | Drum for a production unit for a non-woven material, method for production of a non-woven material and non-woven material obtained thus | |
| US4085486A (en) | Method of producing needled, non-woven tubing | |
| JPH0639743B2 (en) | Method and apparatus for manufacturing non-cylindrical axisymmetric three-dimensional structure | |
| JP2002539036A (en) | Transfer printing machine | |
| US4138772A (en) | Apparatus for producing needled, non-woven tubing | |
| KR100419556B1 (en) | Apparatus and method for manufacturing ring shaped parts and preforms thereof from synthetic materials | |
| CN1074472C (en) | Method and apparatus of heating synthetic silk | |
| US6203666B1 (en) | Method and device for paper web manufacturing | |
| CA1041282A (en) | Non-woven tubing and production thereof | |
| US4124731A (en) | Needled non-woven tubing | |
| US6284103B1 (en) | Suction roll shell in a paper-making machine and method of manufacturing same | |
| CA1178942A (en) | Method and apparatus for filament winding | |
| US4989799A (en) | Apparatus for winding a multifilament with flat shape and broad width | |
| CA1049242A (en) | Apparatus for the production of non-woven tubing | |
| CN1049029C (en) | Process and apparatus for shaping non-weaving fabric, non-weaving fabric and its use | |
| EP0301325B1 (en) | Yarn withdrawal apparatus and method | |
| US6223398B1 (en) | Web heating device for a fiber processing machine | |
| JP2713381B2 (en) | Ply fabric material and improvements related to the manufacture of the material | |
| EP1777342B1 (en) | Pressing arrangement | |
| EP3333315B1 (en) | Forming section | |
| FI107066B (en) | Press felt and method for making the same | |
| DE2652537C3 (en) | Nonwoven tubular material and method for producing a nonwoven tubular material |