JP4938203B2 - Needle loom, weaving method and fabric woven by these - Google Patents

Description

【００７８】
シャトル織機で手に入る破裂強さのデータは全体の平均だけであった。
【００７９】
【表２】

【００８０】
ミュラーシャトル織機で製造したグラフトの透水性の値は、全体の平均だけであった。
【００８１】
【表３】

【００８２】
^*二又に分かれたグラフトの全体の空隙率の試験は１９９６年１１月に行なった。
【００８３】
【表４】

【００８４】
結論：
結果の統計分析（研究者のｔテスト）から、縫合線の維持力を除き、ニードル織機とシャトル織機のグラフトの物理的なパラメータは違っていることが分かる。ニードル織機のグラフトは有意に透水性が低く、縦の引張り強さが高く、壁の厚さが薄い。これら特徴はグラフトの性能を高めるであろう。
【００８５】
しかし、ニードル織機のグラフトは耳では破裂強さと引張り強さが弱い。破裂強さが弱くはあるが、それでも設定した性能の限界値内に十分おさまっていた。
【００８６】
システムＩＩとシステムＩＩＩの耳の引張り強さの差は有意ではあるが、非常に小さい。耳の強さは、破裂強さ、縦の引張り強さおよびグラフトの血液取扱について重要な要因である。これらパラメータのいずれもマイナスの影響をもっていないため、耳の強さがわずかに低くても、グラフトの臨床的な性能には影響しない。
【００８７】
【表５】
（付表１）

【図面の簡単な説明】
【図１】 ａは二又に分かれた管状グラフトの脚部の断面図であり、ｂは二又に分かれた管状グラフトの本体の断面図
【図２】 図１ｂの本体を織るときに使う２本の緯糸の交換を示す図
【図３】 緯糸針の停止点または停止点の非常に近くで、緯糸を交換するのに適した針を示す図
【図４】 正確に配置しない場合に緯糸が互いにどのようにキャッチするかを示す図
【図５】 織物を針の間隔と同じ量だけ離すために使う２枚の板を示す図
【図６】 血管グラフトの脚部をニードル織機織りする連続ステップを示す図
【図７】 血管グラフトの本体をニードル織機織りする連続ステップを示す図
【図８】 ａはニードル織機用の従来の設計の杼口を示す図であり、ｂは本発明の二本取りニードル織機の操作ができる改良型の杼口を示す図
【符号の説明】
２２ （経糸の上部の外側の）層（第１層）
２４ （経糸の上部の内側の）層（第２層）
２６ （経糸の下部の内側の）層（第３層）
２８ （経糸の下部の外側の）層（第４層）
３０ （第１）経糸
３２ （第２）経糸
３４ （上部の緯糸挿入）針
３６ （下部の緯糸挿入）針[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a needle loom capable of producing a tubular fabric, in particular, a bifurcated tubular graft for medical use. (Needle loom) And a weaving method and a tubular fabric produced thereby.
[0002]
[Prior art]
Two-weave graft (graft) : Transplanted tissue ) Is used to bypass the aorta and iliac arteries.
[0003]
This graft has traditionally had multiple shuttles on each spinning head. (梭) It has been woven with shuttle looms using The shuttle loom inserts the weft yarn by a shuttle (yarn built-in carrier) passed through a shed (that is, an opening formed by separating the warp yarns during weaving operation). The shuttle supplies enough wefts by wefting many times. Weaving with shuttle looms has several problems, but the most important drawback so far is low production. A low total production of around 10% is not uncommon in shuttle weaving, and this figure gets even lower as the size increases. This problem arises from the fact that shuttle looms are inherently limited machines for speeding up weaving. The main disadvantage of shuttle looms is that a large shed is required to penetrate a boat-type shuttle into the warp. In other words, in order to provide a sufficient space between the yarns so that the shuttle can pass, the warp yarns need to be separated and opened relatively large. For this reason, the peak tension becomes high in the warp, which turns and the dart moves from the needle wire to the end of the warp. Large hooks also cause the ends of the warp to be cut greatly and cause the weaving of the weaving yarn to be large. And there was no satisfactory solution to this problem.
[0004]
[Problems to be solved by the invention]
After that, for almost all fabrics, weaving and knitting with needle looms instead of weaving with shuttle looms (Organization) There have been considerable alternatives such as felting.
[0005]
However, neither knitting nor felting can provide a stable quality graft with sufficient density, and weaving with a needle loom has not been used because of technical difficulties. Only shuttle loom weaving was used to produce tubular medical grafts.
[0006]
A needle loom is a shuttleless machine that pulls out a weft thread from a fixed yarn feeder and passes a weft insertion needle (that is, two weft threads enter from the front edge of the weft insertion needle) through the shed. It is a loom. The weft is held on the opposite ear either by the action of knitting or with a stop yarn from another yarn feeder. Simple (not bifurcated) tubular medical grafts can be produced using needle loom technology, but because of technical difficulties, this conventional needle loom technology is not suitable for bifurcated tubular medical grafts. It has not been used successfully.
[0007]
Accordingly, an object of the present invention is to provide a loom and a weaving method that can overcome this technical difficulty.
[0008]
[Means for Solving the Problems]
To achieve the foregoing object, the present invention provides a method for weaving a tubular fabric, the method comprising the steps of making a first layer, a second layer, a third layer, a fourth layer of warp, and said layer A step of weaving with the first and second wefts inserted into the first and second needles from one side of the warp layer, A pair of ears by knitting together a first layer and a second layer, a third layer and a fourth layer, a process for inserting alternately from a predetermined pair of layers, and a weft loop opposite the layers The process for forming.
[0009]
In the first mode of operation, the first weft is alternately inserted into the stack of the first and second layers of warps, the second weft is inserted alternately into the stack of the third and fourth layers of warps, and 2 Make two stacked tubes.
[0010]
In the second operation mode, the first weft is alternately inserted into the first and fourth layers of the warp, and the second weft is alternately inserted into the second and third layers of the warp and folded into a C shape. Make one tube.
[0011]
The present invention further provides a method of weaving a bifurcated tubular fabric, the method comprising the steps of weaving a pair of tubes in the first mode of operation and before or after the same warp and weft. And a step for weaving one tube in the second operation mode.
[0012]
The weft loops may be knitted together or together with the binding thread.
[0013]
Preferably the tubular fabric is a surgical graft or a veterinary graft, more preferably an aortic graft or iliac graft formed in two parts.
[0014]
Further, as another feature, the present invention is in a needle loom for weaving a tubular woven fabric, and the needle loom is arranged in a first layer, a second layer, a third layer, and a fourth layer in which warp yarns are overlapped. A warp forming means for forming a shed on each of the warp layers, a first weft insertion needle and a first weft insertion needle for inserting the first and second wefts from one side of the warp layer. Two weft insertion needles and upper and lower ear knitting means on the opposite side of the warp layer for knitting together the weft loops formed respectively in the first and second layers and the third and fourth layers of warp And alternately passing the first weft through the first and second layers of the warp and passing the second weft through the third and fourth layers of the warp alternately to form two superposed tubes. In the first mode, the first weft is passed through the first and fourth layers of the warp alternately, and the second weft is passed through. Control means capable of selectively operating the needle loom in one of two modes of the second mode forming one tube folded in a C shape by alternately passing through the second layer and the third layer It consists of.
[0015]
In a preferred embodiment, the first warp insertion needle and the second weft insertion needle are arranged to be stacked with a spacing similar to the spacing between the warp layers, and the control means has a longitudinal direction relative to the weft insertion needle and the warp layers. Can be operated to cause
[0016]
In a preferred embodiment, the first weft insertion needles are alternately arranged in the first layer and the second layer of the warp, and the second weft insertion needles are alternately arranged in the third layer and the fourth layer of the warp. When operating in the mode, the weft is switched between the first and second insertion needles in synchronism with the relative movement.
[0017]
Also preferably, the first weft passes through the first weft selector, and the second weft passes through the second weft selector located closer to the warp layer than the first weft selector.
[0018]
It should be noted that looms usually form a substantially horizontal layer in the direction in which the weft crosses the longitudinal extension of the warp so that it has an inherent “top” and “bottom” (determined by natural gravity). So, as a result, a stack of warp yarns automatically has “up” and “down” relative to their relative placement. However, since the operation of the needle loom according to the present invention is independent of gravity, the terms “upper” and “lower” are not particularly used.
[0019]
The needle loom of the present invention is particularly suitable for the production of medical and veterinary grafts, and is particularly suitable for vascular grafts. Needle looms can also be used for bifurcated tubular grafts.
[0020]
However, the needle loom of the present invention is not limited to weaving a bifurcated tubular graft. If in the second mode of operation of the needle loom, the needle loom can also weave a tapered tubular graft, in particular a tapered tubular graft in which the taper is symmetrically inclined from both lateral ends of the tubular graft. Furthermore, if in the first mode of operation of the needle loom, the needle loom weaves two relatively thin tubular grafts at the same time, which doubles the production compared to weaving one relatively thin tubular graft.
[0021]
Preferably, the method described above uses Muller System II ears (when wefts are interwoven with weft yarns) or Muller System III ears (when wefts and weft yarns are interlaced at once). The Muller System II ear has a finer weave edge and a lower bulk, and the Muller System III ear is thicker, but the transmission control is enhanced.
[0022]
DETAILED DESCRIPTION OF THE INVENTION
1a and 1b are cross-sectional views of a leg and a body, respectively, of a bifurcated tubular graft, and are cross-sectional views cut transversely in the weaving direction. FIG. 2 illustrates the replacement of the two wefts used when weaving the body of FIG. 1b. FIG. 3 illustrates a needle suitable for changing the weft thread at or near the stop point of the weft needle. FIG. 4 illustrates how wefts catch each other if not correctly positioned. FIG. 5 illustrates two plates used to separate the fabric by the same amount as the needle spacing. Figures 6a to 6f illustrate the successive steps of weaving the leg of the vascular graft. Figures 7a to 7g illustrate successive steps of weaving the body of the vascular graft. FIG. 8a shows a well of a conventional design for a needle loom. FIG. 8b shows an improved shed that allows the operation of the two-take needle loom of the present invention to be produced in a single piece in the form of a four-layer graft.
[0023]
It should be noted that in the cross-sectional view, the graft should be held flat by the plate, but for the sake of clarity, the graft is shown so that each thickness of the fabric can be distinguished.
[0024]
First, as shown in FIG. 1a and FIG. 1b, the bifurcated tubular graft is folded so that one leg 2 is woven flat on the other leg 3 (FIG. 1a), and the body 4 is Fold along the center (FIG. 1b) and weave to form a four layer graft. The weaving of the legs 2 and 3 as shown in FIG. 1a is simple and can be achieved with standard weaving techniques, but weaving the body 4 has many problems.
[0025]
The solution of the present invention consists in weaving the body 4 with two wefts 5 and 6 (FIG. 2), while weaving one weft 5 alternately on the upper and lower layers 7 and 8 of the four layers of graft. Two weft threads 6 weave the two central layers 10, 9 alternately. In order to do this, the two wefts 5, 6 must be interchanged. In known methods, this would require three wefts. The first weft is for the main body, the second weft is for one leg of the bifurcated graft, and the third weft is for the other leg of the bifurcated graft. These wefts will not be replaced in the manner envisioned by the present invention.
[0026]
In order to catch the weft that was replaced at the entrance, we tried a bifurcated weft needle, but it was not possible to make a mouth with such a wide leading edge with respect to the weft needle. Therefore, in the form of a needle 11 as shown in FIG. 3, each of the two wefts 5 and 6 is arranged so that the weft insertion needles 5 and 6 are exchanged at the stop point of the weft insertion needle or very close to the stop point when exiting from the mouth A weft insertion needle was tried. To do this, the upper weft insertion needle must receive the weft from below rather than from above in the usual way. This will be explained in more detail with reference to FIGS. 7a to 7g. An important feature of the weft insertion needle 11 which provides an improved commercially available weft insertion needle is that it can carry the weft (not shown in FIG. 3) during movement through the dovetail 17 through the shed. At the free end 19 of the needle 11 in shape and size.
[0027]
The weft insertion needle 11 has a standard diameter and length, and is determined to match the woven loop itself. Improvements in the weft insertion needle 11 that are suitable for use in the present invention relate to the radius of curvature of the needle 11 and the depth and spacing of the teeth 18, 18 'forming the grooves 17. In essence, the radius of curvature is increased so that the needle bends less than a conventional needle. In essence, the shape of the weft insertion needle is changed so that the free end 19 and the groove 17 are as close as possible, but not touching the weft selector at the end of each transverse insertion cycle.
[0028]
The appropriate shape of a conventional needle is shown by the dotted line in FIG. 3 for comparison. Further, the interval between the teeth 18 and 18 'is made larger than the interval between the conventional needles so that the wefts can be easily exchanged, the depth of the grooves 17 is increased, and the wefts stay firmly in the grooves 17. To do.
[0029]
It is practically possible to cause the wefts 5 and 6 of the main body 4 to catch each other at the entry point to the warp so as to have a cross section as shown in FIG. The solution in this embodiment of the invention is to ensure that the weft thread 6 interweaving the inner layer of the body 4 is located in a weft selector near the weaving fabric.
[0030]
The weft 5 that weaves the upper and lower layers 7 and 8 needs to have fewer wefts when weaving the main body than the yarn necessary when weaving the legs, and the second weft 6 correspondingly Need to increase the yarn. Semi-forced weft feed (compared to forced weft feed) can meet these diverse requirements.
[0031]
When weaving on the two-handed needle loom of this embodiment of the present invention, a longitudinal gap of at least 5 millimeters is required between the ear knitting needles 14, 16 (FIGS. 2, 4 and 5) for mechanical reasons. A similar gap is required between the weft insertion needles (not shown in FIGS. 2, 4 and 5). Such gaps will cause a frayed portion at the tube entry point (ie, where the weft insertion needle enters), especially when weaving the graft body. The first plate 12 (FIG. 5) almost solves this problem by closing the entry point gap to a minimum. Even in the worst case of weaving the graft body, it is necessary to redesign the warp draft as shown in Table 5 (Appendix 1).
[0032]
Normally, when weaving with a double take-up needle loom, the shed is made so that the vertical position of the fabric is always constant, the middle and upper two layers are made of upper wefts and are always pulled upwards, The lower two layers made of lower weft are pulled downwards. This is the case where the legs are woven and is important for stable weaving. However, in order to weave the main body, the position of the weft thread is periodically changed. Therefore, in order to keep the cloth at a constant height, the second plate 13 is inserted (FIG. 5).
[0033]
The two plates 12 and 13 are arranged, and the shed and the heddle wire are improved so that the weft can pass cleanly. FIG. 8a shows a schematic diagram of a conventional needle loom shed design, and FIG. 8b shows an improvement suitable for operation of the present invention when making the body and / or weaving the legs simultaneously. In FIGS. 8 a and 8 b, the shed is a gap drawn by the upper warp 14 and the lower warp 15. In the improved shed design of FIG. 8b, each weft has both upper and lower warps, and the warps have separate beams 16, 16 ′. The woven fabric is made as two separate layers 7,8. The position of the weft insertion needle 11 at the cloth drop point is shown for clarity. It should be noted that the length of the upper warp 14, 14 'of the shed must be the same as the length of the lower warp 15, 15' of the same shed, but in the improved design of FIG. 14 'need not be the same length.
[0034]
Details of weaving the graft legs 2, 3 (FIG. 1a) with a needle loom will now be described with reference to FIGS. 6a to 6f, followed by details of weaving the graft body 4 (FIG. 1b) with a needle loom. Will be described with reference to FIG.
[0035]
The operation is essentially various, such as arranging warps in four layers, or equipment for replacing two weft yarns between two weft insertion needles at a given moment of the needle loom movement cycle. The needle loom, which is an improvement of the Mueller needle loom, will be described in detail. For the sake of clarity, FIGS. 6a to 7g show only the parts of the needle loom that are essential for explaining the weaving method of the invention, and the large parts of the needle loom are omitted in the figures.
[0036]
Each of FIGS. 6a to 7g is a cross-section obtained by cutting the weaving direction of the tubular woven fabric transversely, and descends vertically on the surface of the drawing. For the purposes of this description of the present invention, “up” is the direction toward the top of each figure, and “down” is the direction toward the bottom of each figure, and the relative terms “top” and “Lower” is interpreted accordingly. Correspondingly, the terms “left” and “right” are consistent in the same direction in each figure.
[0037]
In each of the successive steps illustrated in FIGS. 6a to 7g, the warp is divided into four separate layers and the layers of the warp are stacked, each of which in turn has its layer shed. Subdivided vertically into the two subordinate layers that form (each of these subordinate layers should be drawn in rows of warps as viewed from the cross section, strictly as a row of dots or small circles, but for simplicity In addition, each subordinate layer of the warp is drawn with one continuous solid line). At the appropriate moment of the needle loom movement circle to be detailed, each of the two subordinate layers of each warp layer has a position where each other alternates so that each weft is successfully interwoven with the warp of that layer ( In the drawing, the parts of the needle loom for arranging the warp yarns in four layers and the parts forming the shed by each of these layers are not shown). It should be noted that the two subordinate layers of each warp layer periodically replace each other, but the overall layer does not change its relative position within the stack.
[0038]
With particular reference to FIG. 6a, the warp yarns are separated from each other by four equally spaced layers: an upper outer layer 22, an upper inner layer 24, a lower inner layer 26, and a lower outer layer. 28 stacked 20. Each of these four layers is subdivided into a pair of subordinate layers by means of a clerk forming means (not shown), and the vertical position of the subordinate layer relative to the other subordinate layer in each pair of subordinate layers is The forming means can replace each other at the appropriate moment of the needle loom's movement cycle so that the first weft 30 or the second weft 32 can be woven at the appropriate stage of the weaving cycle, as described below.
[0039]
On the left side of the stack 20 is a pair of movable weft insertion needles, ie, an upper weft insertion needle 34 and a lower weft insertion needle 36, each substantially the same as the single needle 11 shown in FIG.
[0040]
The needles 34 and 36 are respectively engaged with the first and second wefts 30 and 32, and each weft is inserted into a shed formed between one predetermined subordinate layer of the four warp layers 22, 24, 26 and 28. Inserted (as detailed below). The needles 34 and 36 are mechanically connected to each other and move in conjunction with each other in the lateral direction. When the needle loom moves in its first mode of operation and weaves the legs 2, 3 of the graft (as illustrated in detail in Figures 6a to 6f), the first weft 30 is continuously with the upper weft insertion needle 34 and The second weft 32 is continuously engaged with the lower weft insertion needle 36. However, when the needle loom moves in its second mode of operation and weaves the graft body 4 (as illustrated in detail in FIGS. 7a to 7g), the first weft 30 is the various parts of the weaving cycle and the upper weft Engaging with the insertion needle 34 (FIGS. 7a, 7b, 7c and 7g) or engaging the lower weft insertion needle 36 (FIGS. 7d, 7e and 7f), the second weft 32 is now the first It is carried by either the weft insertion needle 34 or the weft insertion needle 36 that does not carry the weft 30 (in the drawing, the first weft 30 and the second weft 32 are replaced with the upper weft insertion needle 34 and the lower weft insertion needle 36). This means is not shown). On the right side of the stack 20 is the pair of earknitting needles previously described with reference to FIGS. 2, 4 and 5, ie, the upper earknitting needle 14 and the lower earknitting needle 16. During both modes of operation of the needle loom, the upper weft insertion needle 34 on either weft 30, 32 passes as it passes through the respective head of either of the two upper warp layers 22, 24. The ear knitting needles 14 operate to knit adjacent ears together at the right ends of the two upper weft layers 22, 24. Also, during both modes of operation of the needle loom, when the lower weft insertion needle 36 passes through the sheds of either of the two lower warp layers 26 and 28 to the wefts 30 and 32, the lower ear knitting needle 16 operates. Then, adjacent ears are joined together at the right ends of the two lower warp layers 26,28.
[0041]
At all times, the ear knitting needles 14 and 16 are maintained at the same height relative to the stack 20 of warp layers.
[0042]
FIG. 6a includes reference numbers for all parts and materials, but for ease of understanding these reference numbers may require one or more reference numbers to understand a figure if it is deemed necessary or convenient. Are omitted in FIGS. 6b to 7g.
[0043]
Returning to FIG. 6a, this shows that the weft insertion needles 34, 36 are pulled laterally from the warp layer stack 20 to the left, with the upper needle 34 being two subordinate layers of the upper inner layer 24. The first weft 30 is dragged from the shed between the two, and the lower needle 36 drags the second weft 32 from the shed between the two subordinate layers of the lower outer layer 28 (which is the arrangement of FIG. 6a). (See the diagram in FIG. 6f below for an explanation of what happens). FIG. 6 a shows the ear knitting needles 14, 16 being pulled laterally from the warp layer stack 20 to the right, with the upper ear knitting needle 14 knitting the ear just before the two upper layers 22, 24. The lower ear knitting needle 16 that has been knitting ears just before joining the adjacent right ends joins the adjacent right ends of the two lower layers 26,28. After knitting the layers 24, 28, the layers of yarn layers are rearranged and the layers 22, 26 are woven.
[0044]
Reference is now made to FIG. 6b, which illustrates the operational phase of the first mode needle loom immediately after the previously completed phase described above with reference to FIG. 6a. As shown in FIG. 6b, the weft insertion needles 34, 36 are both moved completely to the right, allowing the upper needle 34 to pass through the shed formed between the two subordinate layers of the upper outer warp 22, A needle 36 is passed through the shed formed between the two subordinate layers of the lower inner warp layer 26. Thereby, the upper needle 34 carries the first weft 30 to the right, from the mouth of the upper outer layer 22 to the right side of the layer 22, where the weft 30 is knitted by the upper ear knitting needle 14 and adjacent to the upper The right end of the inner layer 24 is joined to these two ends with a common ear. The lower needle 36 carries the second weft 32 to the right side from the shed of the lower inner layer 26 to the right side of the layer 26, where the weft 32 is joined by the lower ear knitting needle 16 and adjacent to the lower portion. The right end of the outer layer 28 of the two layers joins these two ends with a common ear.
[0045]
After the weaving and ear knitting steps of FIG. 6b, the weft insertion needles 34, 36 are pulled completely to the left from the layers 22, 26 as shown in FIG. 6c to bring the woven first weft 30 into the upper outer side. Leave the layer 22 and leave the woven second weft 32 on the lower inner layer 26. At the same time, the ear knitting needles 14, 16 are pulled completely to the right and away from the newly knitted ear.
[0046]
Turning now to FIG. 6d, this shows the stack 20 all moved up. This movement of the stack is such that the upper inner layer 24 is leveled with the upper weft insertion needle 34 and the lower outer layer 28 is level with the lower weft insertion needle 36 for the first operation of the needle loom. Create the necessary array for the next stage of the mode. The necessary movement of the stack can be achieved by any suitable procedure.
[0047]
FIG. 6e shows the next stage of the first mode of operation of the needle loom, where both the weft insertion needles 34, 36 have been moved completely to the right, and the upper needle 34 is moved to the upper inner layer 24-2. A throat formed between two subordinate layers is passed through, and a lower needle 36 is passed through a pier formed between the two subordinate layers of the lower outer warp layer. Thereby, the upper needle 34 carries the first weft 30 to the right, from the mouth of the upper inner layer 24 to the right side of the layer 24, where the weft 30 is knitted by the upper ear knitting needle 14 and adjacent upper The right end of the outer layer 22 of the two layers joins these two ends with a common ear. This also causes the lower needle 36 to carry the second weft 32 to the right, from the mouth of the lower outer layer 28 to the right side of the layer 28, where the weft 32 is knitted by the lower ear knitting needle 16 and adjacent. The right inner edge of the lower inner layer 26 joins these two ends with a common ear.
[0048]
After the knitting end knitting stage of FIG. 6e, the weft insertion needles 34, 36 are completely pulled to the left from the layers 24, 28, as shown in FIG. 6f, so that the first weft 30 is the upper inner layer 24. And the second weft 32 is woven into the lower outer layer 28. At the same time, the ear knitting needles 14, 16 are completely pulled away to the right and away from the newly knitted ear.
[0049]
After the stage illustrated in FIG. 6f, the stack 20 is moved all the way down. This is the opposite of the upward movement of the stack 20 described with reference to FIG. 6d, making the arrangement shown in FIG. 6a, thus completing the complete cycle of needle loom movement in the first mode of operation of the needle loom.
[0050]
It should be noted that beating (i.e., driving a newly woven weft) occurs at an appropriate point in the sequence of steps described above (e.g., step shown in FIG. 6c and / or step shown in FIG. 6f). Any means suitable for beating may be employed, but such means are omitted in the drawing.
[0051]
While appropriately sending out the wefts 30 and 32, the operation cycle described above with reference to FIGS. 6a to 6f is repeated an appropriate number of times, and two tubes (2 in FIG. 1a) knitted in the first operation mode of this needle loom. And 3) roll and advance from the needle insertion area. When two tubes of a predetermined length are woven, the operation of the needle loom is switched to the second operation mode of the needle loom. This will be described with reference to FIGS. 7a to 7g.
[0052]
In the second mode of operation of the needle loom, one tube that functions as the graft body 4 (FIG. 1b) will be woven. When the two pipes are changed to one pipe or are alternately changed from one pipe to two pipes, each branch portion is formed in the fabric produced by the operation of the needle loom. Each bifurcation is a Y-merging section of a synthetic graft as it is cut longitudinally with normal continuous alternating one / two tube formations knitted with a needle loom.
[0053]
FIG. 7a illustrates the weft insertion needles 34 and 36 drawn laterally from the warp layer stack 20 to the left, with the upper needle 34 between the two dependent layers of the lower outer layer 28. The first weft 30 is dragged out from the lower needle 36 and the second weft 32 is dragged out from the shed between the two subordinate layers of the upper inner layer 24 (explaining what the arrangement of FIG. 7a looks like) See the diagram of FIG. 7g later). FIG. 7 a also shows the ear knitting needles 14, 16 pulled laterally from the warp layer stack 20 to the right, with the upper ear knitting needles 14 knitting ears just adjacent to the two upper layers 22, 24. A knitted lower ear knitting needle 16 that joins the right ends and has just knitted ears joins the adjacent right ends of the two lower layers 26,28.
[0054]
In the first mode of operation of the needle loom (FIGS. 6a to 6f), the arrangement of FIG. 7a is such that the first weft 30 is interwoven into the two upper layers 22, 24 alternately. Ru On the other hand, the second weft 32 is alternately woven into the two lower layers 26, 28, but in the second mode of operation of the needle loom (FIGS. 7a to 7g), the first weft 30 is the two outer layers. Corresponding to the arrangement of FIG. 6a (second mode of operation of the needle loom), except that the second weft yarn 32 is alternately woven into the two inner layers 24, 26 while being alternately woven into 22, 28 Then, as in the first mode of operation of the needle loom, each ear continues to bond the two upper layers 22, 24 together and the two lower layers 26, 28 together).
[0055]
Referring now to FIGS. 7b and 7c, these stages of the second mode of operation of the needle loom (which continues from the stage illustrated in FIG. 7a) are the initial configuration shown in FIG. 7a (FIG. 6a). It corresponds to the same stage of the first mode of operation of the needle loom shown in FIGS. 6b and 6c, except for the differences.
[0056]
The next stage of the second mode of operation of the needle loom illustrated in FIG. 7d is one of the most significant differences to the second mode compared to the first mode of operation of the needle loom, namely the next stage of operation of the needle loom. For preparation, the replacement of the wefts 30 and 32 between the weft insertion needles 34 and 36 is shown. 7a, 7b and 7c, the first weft 30 is carried by the upper weft insertion needle 34 and the second weft 32 is carried by the lower weft insertion needle 36 (that is, the needle loom). The next stage shown in FIGS. 7d, 7e and 7f is to carry the first weft 30 with the lower weft insertion needle 36, as shown in FIGS. 6a to 6f). The two weft threads 32 must be carried by the upper weft insertion needle 34. The weft switching takes place at the stage shown in FIG. 7d, and the replacement is performed by a weft selector (not shown). The weft selector of the second weft 32 is more lateral in the stack 20 than the weft selector of the first weft 30. Being in the close position avoids the undesirable weft tangles described above with reference to FIG. The selection of the weft consists of a heddle wire arrangement for each weft, and the weft passes through the eyes of the weft selector. The weft selector can be moved independently in the direction across the weft insertion direction. Therefore, the weft selector that carries the thread to be inserted into the upper weft insertion needle 34 moves upwards before the next insertion of the cycle at the moment the upper weft insertion needle 34 is fully retracted (shown in FIG. 7). Like). As the weft selector moves upward, the thread lifts from the lower weft insertion needle 36 onto the upper weft insertion needle 34, the thread falls into the groove 17 of the needle 34, and the needle begins the next insertion cycle. . At the same time, the weft selector that carries the yarn to be inserted into the lower weft insertion needle 36 moves the yarn downward to facilitate accurate placement in the groove 17 of the lower weft insertion needle 36. In the second mode of operation of the needle loom, the weft selector is initially in a position to simply lift the weft thread from the upper weft insertion needle at the end of the insertion cycle. At the same time that the position of the weft is changed, the entire stack 20 is moved upward.
[0057]
After the weft replacement shown in FIG. 7d, the next stage of the second mode of operation of the needle loom is shown in FIG. 7e, which is the second weft 32 that is woven into the upper inner layer 24 in FIG. 7e. Corresponding to the first mode stage shown in FIG. 6e, except that the first weft 30 is woven into the lower outer layer 28 (ear knitting continues as before). At the end of the stage of FIG. 7e, the various needles are all retracted laterally as shown in FIG. 7f (this corresponds to FIG. 6f).
[0058]
The final stage of the second operating mode of the needle loom is shown in FIG. Here, the first weft 30 and the second weft 32 are again exchanged between the weft insertion needle 34 and the weft insertion needle 36, the first weft 30 returns to the upper weft insertion needle 34, and the second weft 32 is Return to the lower weft insertion needle 36. At the same time, the entire stack 20 is lowered so as to be opposite to the upward movement in FIG. 7d. With these movements described with reference to FIG. 7g, the configuration of the needle loom returns to the initial configuration of FIG. 7a, thereby causing a cycle of steps to configure the second mode of operation of the needle loom; The cycle of weaving one tube (as detailed above in FIG. 1b) is completed.
[0059]
While properly sending out the wefts 30 and 32, the operation cycle described above with reference to FIGS. 7a to 7g is repeated an appropriate number of times, and the needle insertion area of the folding single tube woven in the second operation mode of this needle loom (FIG. 1b Continue winding from 4). Once the predetermined length of the folded single tube has been woven, the needle loom is returned to the first mode of operation of the needle loom (as described above with reference to FIGS. 6a to 6f).
[0060]
The drive / control device for alternating needles is a standard instrument with a commercially available two-take needle loom. Switching from one tube to two leg weaving, and vice versa, is easily controlled by programming a control unit of a commercially available two-handed needle loom.
[0061]
Improvements and modifications of the needle loom and weaving method described above can be employed without departing from the scope of the invention. For example, if the positions of the two weft insertion needles 34 and 36 can be interchanged during the operation of the needle loom, the second operation mode of the needle loom (FIGS. 7a to 7g) is between the weft insertion needles 34 and 36. Thus, even if the wefts 30 and 32 are not exchanged, it can be performed by exchanging the positions of the needles in the steps of FIGS.
<Example 1: Risk assessment>
Currently, bifurcated grafts are manufactured on a Mueller shuttle loom. These looms are relatively slow and can be unreliable, and the grafts produced with them tend to be soiled. Therefore, an object is to produce a bifurcated graft using a Mueller needle loom. This loom can provide a number of advantages, including:
(1) The time required to produce a bifurcated graft is shortened.
(2) The reliability is improved, and if there is a problem during production, the operation can be stopped and a new graft can be produced immediately. This is different from shuttle looms where the production of defective grafts must be completed before starting production of new grafts.
(3) Manufacture a graft with less contamination.
[0062]
In addition to being woven with different looms, the grafts made with needle looms are made with Muller System II ears, not with the Muller System III ears used in other woven grafts. The Muller System II ear is thinner and less bulky than the Muller System III weave end.
[0063]
Müller System II--weaves the weft yarn with the binding yarn. This type of ear has a thinner weave edge and a lower bulk.
[0064]
Müller System III--Ear interweaves weft and binding yarns at once. This type of ear is thicker and more resistant to infection.
[0065]
Tests were conducted to observe the following:
(1) Did the graft produced by the needle loom leak as much blood as that produced by the shuttle loom?
(2) Does the Muller System II ear leak blood from the graft?
(3) Does the graft produced by the needle loom have different physical properties from those produced by the shuttle loom?
(4) Is the Muller System II ear weaker than the Muller System III ear?
Rating:
(1) A blood bench test was carried out on the gel-sealed graft produced on a Mueller needle loom. Particular attention was paid to the ears so that the woven edges of the Muller System II were not adversely affected. The tests performed are similar to ISO 7198 paragraph 8.2.3, except that blood from anticoagulated animals is used as the fluid. Briefly, a graph was drawn on a blood container maintained at 120 mm Hg with a conditioned air source. Pour blood into the graft and note the leak. Rely on observation of leakage (rather than measuring capacity) because the capacity to leave is small. The results are shown in Example 2.
(2) A physical test was performed on the graft produced by the needle loom. This test was performed according to ISO 7198 as detailed in Example 3. This result was compared with previous results of grafts produced on shuttle loom. Again, particular attention was paid to the ears of the graft for burst strength and water permeability. The results are shown in Example 3.
(3) The tensile strength of the ear was determined. This was done by cutting the graft into 2 cm pieces. The graft was then cut longitudinally so that the ears were placed in the middle of the fabric. The tensile strength was then tested according to ISO 7198, paragraph 8.3.2. The results for the needle loom and shuttle loom are shown in Example 3.
result:
(1) From the blood test results, it was found that the improvement did not affect the blood handling characteristics of the graft.
(2) A report on physical testing is attached to Example 3. From this result, it was found that the graft produced by the needle loom was thinner than the shuttle loom graft, strong in the longitudinal direction, and low in porosity. The shuttle loom graft has high burst strength.
(3) Table 4 of Example 3 compares the tensile strength of the ears. From this result, it was found that the ear of the Mueller system II was slightly weaker than the Mueller system III.
Conclusion:
The blood test results showed that the needle loom graft works as well as the shuttle loom graft.
[0066]
From physical tests, it was found that grafts woven with a needle loom had a lower burst strength than grafts woven with a shuttle loom. However, this low burst strength far exceeded the limit set for bifurcated grafts. The tensile strength of the Muller System II ear was slightly lower than the Muller System III ear. Although significant, this difference is not high enough to affect the clinical performance of the graft. A graft woven with a needle loom is thinner than a graft woven with a shuttle loom, is strong in the machine direction, and has a low water porosity.
[0067]
Other risks demonstrated by this improvement were identified and treated in trials and found that the benefits of the improvement were far superior.
<Example 2: Results of blood bench test>
Method:
Paragraph 8.2 of ISO 7198, except that seven bifurcated grafts woven from a needle loom with an inner diameter of 18 × 9 mm, taken from the same batch, were used as the test solution. Blood test according to .3. All of these grafts were produced on a Mueller needle loom using Muller System II ears. The catalog number for these grafts was 731809 and the batch number was 29784. In addition, the results of these grafts were produced on a Mueller shuttle loom and compared with equivalent grafts tested in blood in August 1997. The grafts tested were as follows:
[0068]
Catalog number: 732211, batch number 25630, 25682
Catalog Number: 732010, Batch Number 24517B
Catalog Number: 731407, Batch Number 25034 / A, 24505 / 1A
result:
[Needle loom]
None of the initial pressurization--grafts leaked.
[0069]
Initial pull--two of the grafts did not leak. Of the other 5 sheets, 3 had a small spot leak at the bifurcated branch, and the other 2 leaked at the leg just below the branch.
[0070]
Second pull--one of the grafts did not leak and the remaining six grafts had a small leak at the bifurcated branch.
[0071]
Overall performance--All grafts performed very well. A leak occurred, but it was very small and sealed rapidly. The total amount of blood lost from each graft was too small to measure accurately.
[Shuttle loom]
Initial pressurization--four of the grafts did not leak and the rest had very small spot leaks on the legs and body of the graft.
[0072]
Initial pull--two of the grafts did not leak and the remaining three had small leaks at the branch.
[0073]
Second pull--two of the grafts only leaked at the branch, but the remaining three had 1-3 small spot leaks, which were mainly the legs of the graft.
[0074]
Overall performance--The graft worked very well. Only a small spot leak occurred at the leg of the graft and was sealed rapidly. The total amount of blood lost from the graft was negligible.
Conclusion:
The grafts produced on the Mueller needle loom functioned as well as those produced on the Mueller shuttle loom. The Muller System II ear also worked very well, and no blood was lost from the graft.
<Example 3: Physical characteristics of a bifurcated graft produced by a Mueller needle loom and a shuttle loom>
Introduction:
The physical properties of a bifurcated graft made with a Mueller needle loom (Muller System III ear) were compared to those of a bifurcated graft made with a Mueller shuttle loom (Muller System III ear).
Method:
The bifurcated graft was tested according to the following specifications of ISO 7198.
[0075]
8.2.2--Determining water porosity with Buxton & Cooley type rigs
8.3.3.2--Measurement of product burst strength: Main body, seam / black line, bifurcation
8.5--Measurement of Relaxed Inner Diameter
8.2.3 ^* -Porosity test of the entire graft
8.8--Suture line maintenance force
8.3.2--Vertical tensile strength
8.7.4.2--Wall thickness
^* The test solution was replaced with a propanol solution containing 8% glycerin.
test:
The following grafts were tested:
[0076]
Nine grafts were prepared from batch 29878. These were 18 mm × 9 mm bifurcated grafts produced on a Mueller needle loom. The porosity of the entire graft of nine 18 mm × 9 mm grafts (batch 29784) produced on a Mueller needle loom was also tested. A physical test of a bifurcated graft made on a shuttle loom has already been performed and the results were used to compare with a needle loom graft.
result:
[0077]
[Table 1]

[0078]
The only burst strength data available on the shuttle loom was the overall average.
[0079]
[Table 2]

[0080]
The water permeability values of the grafts produced on the Mueller shuttle loom were only the overall average.
[0081]
[Table 3]

[0082]
^* The total porosity of the bifurcated graft was tested in November 1996.
[0083]
[Table 4]

[0084]
Conclusion:
From the statistical analysis of the results (researcher's t test), it can be seen that the physical parameters of the needle loom and shuttle loom grafts are different, except for the suture retention. Needle loom grafts have significantly lower water permeability, higher longitudinal tensile strength, and thinner wall thickness. These features will enhance the performance of the graft.
[0085]
However, the needle loom grafts have weak bursting strength and tensile strength at the ears. Although the burst strength was weak, it was still well within the set performance limits.
[0086]
The difference in ear tensile strength between System II and System III is significant but very small. Ear strength is an important factor for burst strength, longitudinal tensile strength and graft blood handling. None of these parameters have a negative effect, so even slightly low ear strength does not affect the clinical performance of the graft.
[0087]
[Table 5]
(Appendix 1)

[Brief description of the drawings]
1 is a cross-sectional view of a leg portion of a bifurcated tubular graft, and b is a cross-sectional view of a main body of the bifurcated tubular graft.
FIG. 2 is a diagram showing replacement of two wefts used when weaving the main body of FIG. 1b.
FIG. 3 shows a needle suitable for changing the weft thread at or near the stop point of the weft needle
FIG. 4 shows how wefts catch each other when not correctly positioned
FIG. 5 shows two boards used to separate the fabric by the same amount as the needle spacing.
FIG. 6 shows a sequence of steps for weaving a vascular graft leg with a needle loom.
FIG. 7 shows successive steps of weaving the body of the vascular graft with a needle loom.
FIG. 8a is a view showing a conventionally designed shed for a needle loom, and FIG. 8b is a view showing an improved shed capable of operating the two-take needle loom of the present invention.
[Explanation of symbols]
22 Layer (outside of upper part of warp) (first layer)
24 (inside the upper part of the warp) layer (second layer)
26 Layer (3rd layer) (inside the lower part of the warp)
28 (outside of the lower part of the warp) layer (fourth layer)
30 (First) Warp
32 (Second) Warp
34 (Upper weft insertion) Needle
36 (Lower weft insertion) Needle

Claims (11)

A method for weaving a bifurcated tubular fabric, the method comprising:
a. A process for making a laminate of the first, second, third and fourth layers of warps;
b. The first weft and the second weft are inserted from the one side of the warp layer, and the first and second wefts are woven from each side of the warp layer. insert alternately selective pair, the other side of the weft loops of the layer, first and second layers, woven together in the third and fourth layers, the process for making a pair of ears When,
c. A process for making two superposed tubes by alternately inserting first weft yarns into the first and second layers of warp yarns and alternately inserting second weft yarns into the third and fourth layers of warp yarns When,
d. Using the same warp and weft before or after step c, the first weft is inserted alternately into the first and fourth layers of the warp, and the second weft is alternately inserted into the second and third layers of the warp. Insert to make one tube folded in a C shape, thereby providing a bifurcated fabric
Weaving process which is characterized a call. The weaving method according to claim 1, wherein the weft loops are knitted together. 3. The weaving method according to claim 1, wherein the weft loop is knitted together with the binding yarn. 4. The method according to any one of claims 1 to 3, wherein the tubular fabric is a surgical graft or a veterinary graft. 5. A method according to claim 4, wherein the tubular fabric is an aortic graft or iliac graft. A tubular woven fabric produced by the method according to claim 1. A graft produced by the method according to any one of claims 1 to 3 . A needle loom for weaving a tubular fabric, the needle loom
A warp arrangement means for arranging the warp layers on the first, second, third, and fourth warp layers,
A hook forming means for forming a hook on each of the warp layers;
A first weft insertion needle and a second weft insertion needle for inserting a first weft and a second weft from one side of the warp layer;
Upper and lower ear knitting means on opposite sides of the warp layer for knitting together the weft loops formed respectively in the first and second layers of warp and the third and fourth layers;
  A first mode in which two superposed tubes are formed by alternately passing the first weft through the first and second layers of warp and the second weft through the third and fourth layers of warp. And alternately passing the first weft through the first and fourth layers of the warp and passing the second weft through the second and third layers of the warp alternately, Control means capable of selectively operating the needle loom in one of two modes of the second mode to be formed;
A needle loom characterized by comprising: 9. The needle loom according to claim 8, wherein the first weft insertion needle and the second weft insertion needle are arranged so as to be stacked at an interval similar to the interval between the warp layers, and the control means includes a weft insertion needle and the warp layer. A needle loom characterized by being capable of producing an overall vertical movement. The needle loom according to claim 9, wherein the first weft insertion needles are alternately arranged with the first layer and the second layer of the warp, and the second weft insertion needles are alternately arranged with the third layer and the fourth layer of the warp, A needle loom characterized in that when operating in the second mode, the warp is switched between the first weft insertion needle and the second weft insertion needle in synchronization with the overall movement. 11. The needle loom according to claim 10, wherein the first weft passes through the first weft selector, and the second weft passes through the second weft selector positioned closer to the warp layer than the first weft selector. A needle loom characterized by the above.

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