FR2710520A1 - Method for forming a rigid and flexible textile structure which has high resistance to traction and buckling and has good compression behaviour - Google Patents

Abstract

Method for forming a rigid textile structure, characterised by the following stages: - winding a first textile element (12) so as to form loops; - knotting (15) the two ends of the textile element; - fixing the end of a second textile element; - winding this second element in spirals; - inserting a rigid eyelet (1, 1') into each of the two figure-of-eight loops; - winding a third textile element helically; - fixing a fourth textile element on this new structure; - winding this fourth textile element in contiguous spirals; - inserting the end of this fourth textile element into the loop of a feed-through sleeve until this end disappears and is blocked under the loops of the winding; - finally, cutting the free end level with the structure formed. Application: vertebral ligament.

Description

PROCESS FOR PRODUCING A RIGID TEXTILE ASSEMBLY AND
FLEXIBLE. HAVING HIGH TENSILE STRENGTH
AND A GOOD HOLD IN COMPRESSION AND FLAMBAGE.

 The invention relates to a method for producing a rigid and flexible textile assembly, having a high tensile strength and good resistance to compression and buckling; it relates more particularly to a process for winding a textile element, such as a thread, a strand, a braid, a cord, around two supports with a parallel axis, such as pins, screws, in order to give to the whole a maximum tensile strength, close to that of the basic textile element, and a maximum compressive and buckling resistance, while remaining flexible in all planes.

 The invention relates more precisely to a method for producing a synthetic vertebral ligament, of the type described in European patent application EP-A-0 478 470, corresponding to American patent US-A-5 180 393.

This process for producing a rigid and flexible textile assembly, having a high tensile strength and good compression and buckling behavior, is characterized in that it consists:
A - to wind a first flexible filiform textile element around two parallel axes, forming a plurality of continuous beads;
B - to tie the two ends of the filiform textile element by enclosing the plurality of loops formed, so as to produce a set in eight while mixing loose ends;
C - to remove the two parallel axes;
D - to fix on this knot by means of the free ends the end of a second filiform textile element
E - to surround in coils this second element on the two loops of the set of eight, so as to cover it with a protective sheath;
F - to fix the free end of the second filiform textile element on the knot of the figure-eight assembly by means of the free ends;
G - to insert in each of the two flanges of this new set of eight a rigid eyelet;
H - to wind on the textile assembly formed in a helix and on several layers a third filiform textile element formed of parallel strands, taking care, at least in the penultimate layer, to provide a slurry then partially covered by said winding;
I - to cut one of the two strands flush with the sheath formed, then to pull on the cleared strand until substantial reduction in the sulk along H;
J - to be fixed on this new assembly by means of the strand released according to I, in its middle, a fourth threadlike textile element;
K - to wind this fourth filiform textile element in contiguous turns on the assembly according to I, but in the opposite direction to the winding according to H, and taking care to release the end of the cleared strand according to I;
L - to insert the end of this fourth filiform textile element into the loop of a grommet, then to pull on the open strand according to I, so as to insert one of the ends of the fourth textile element under the winding according to K, and to wind the other end in another layer in the opposite direction to the previous one and to introduce this second end into the loop of the grommet, until this end disappears and locks this end under the coils of the winding ;
M - and finally, to cut the free end flush with the assembly produced.

Advantageously, in practice:
- the filiform textile elements are made of a high tenacity retractable polyester yarn, and the assembly according to phase M is retracted in the oven to obtain the optimal properties;
- The first and third filiform textile elements consist of a multifilament synthetic yarn, while the second filiform element is in the form of a flat braid, and the fourth element in the form of a braid with a square section;
- one of the filiform textile elements is assembled with a metallic wire, detectable by radioscopy.

 In a practical embodiment, the beads according to the first step A have the shape of an eight.

 In practice, the two eyelets according to phase G are made of metal and have on one side a concave opening and on the other a convex opening, and on the edge a concave housing intended to receive the end of the ends of the assembly. in eight according to step F.

 As already said, the invention is particularly useful for the manufacture of synthetic vertebral ligaments in accordance with the teachings of the abovementioned patent application EP-A-0 478 470.

 The manner in which the invention can be implemented and the advantages which ensue therefrom will emerge more clearly from the embodiment which follows, supported by the appended figures.

 Figures 1 and 2 show respectively seen in section (fig. 1) and seen from the front (fig. 2), an eyelet according to the invention.

 Figures 3 to 17 schematically show the different stages of the manufacturing process according to the invention.

 The method and the vertebral ligament in accordance with the invention make use of eyelet-shaped journals designated by the general reference (1), shown in detail in FIGS. 1 and 2. This hollow metal eyelet (1), such as stainless steel, chrome / cobalt steel, or preferably titanium alloy, follows the general shape of a diabolo. This eyelet comprises on the external face (2) a concave housing (3) intended to receive the head of the ligament fixing screw. This face (2) is associated with a body (4), in which is formed a median groove (5) associated in turn with a convex boss (6) complementary to the concave housing (3). This convex boss (6) is intended to be embedded in the articular process. A central channel (7) allows the passage of the fixing screw.

 In a practical embodiment, the eyelets (1) have an external diameter of ten millimeters and an internal diameter of five, and a groove of five millimeters.

 To make a synthetic vertebral ligament, the procedure is as follows.

 On a workbench (see Figures 3 and following), place two parallel axes (10,11) of the same diameter. In a variant, these two mounting pins (10,11) could receive eyelets (1), similar to those detailed in Figures 1 and 2 and described above.

 Around these two mounting axes (10,11), an eight-shaped sulk (12) is produced with a sliding knot (13) by means of a polyester thread of 1100 dtex, untwisted, of 89 strands, at high toughness and high thermal shrinkage. Care is taken to provide a free end (14) to the sliding knot (13) over a length of about thirty centimeters (see Figure 3). Then, still from a spool of the same 1100 dtex / 89 high tenacity polyester yarn (see Figure 4), about fifty turns of this yarn are wrapped around eight around the mounting pins (10,11). In a variant, on the first four turns, the polyester thread is lined with a stainless steel thread 8 / 100th of a millimeter in diameter.

Phase B (Figure 5)
After the last turn (see Figure 5), we make a knot in cross (15) with the previous free end (14) and the end (16) of the wire (12) wound in eight and this in the center of the winding in eight.

 The free end (16) is cut flush with the knot.

 The reference (17) designates the eight roll obtained.

Phase C
Once this has been done, the two mounting pins (10,11) are removed, in this case the eyelets (1).

Phase D (Figure 6)
On this winding (17), by means of the free end (14), a piece (20) of flat braid is fixed at the center by its end (21). The reference (22) designates the free portion of this braid (20). In a practical embodiment, this flat braid (20) forming the second filiform textile element, can be obtained by means of a 17-plait braider at one end of a high tenacity polyester thread, having the same characteristics as the wire (12).

Phase E (Figure 7)
The large protruding end (22) is wound around each loop (18,19) of the set in eight (17), in substantially contiguous turns, in slight overlap, as shown in Figure 7, by means of a needle (25) with a round end, the end (22) being placed in the cat of the needle (25). One thus wraps for example five to eight times the braid (20) around each loop respectively (18,19), so as to completely cover each of these two loops to form a protective sheath.

Phase F (Figure 8)
In the center (27) of the assembly, the end (23) of the flat braid (20) is fixed using the protruding end (14), then the protruding end (22) is carefully cut, without however cutting the end free (14).

Phase G (Figure 9)
The two eyelets (1,1 ') with parallel axes are reintroduced again into the loops (18,19). Care is taken to locate one of the two eyelets (1) by a mark (29), such as a loop of thread, in order to determine with certainty the direction of winding of the different layers of textile material.

Phase H (Figure 10)
On the textile assembly thus formed, a layer of a third textile element (30) formed of the same high tenacity polyester yarn analogous to (12) is wound in a helix with contiguous turns and clockwise. . In practice, this wrapping is carried out with contiguous turns by hand, so as to take good care of the free end (14). At the first layer, at one end, a loop (31) is provided with the free end (14) which is covered by the winding with contiguous turns (32) on three layers. This covering extends from one eyelet (1) to the other (1 '), while providing the free end (14). At the penultimate layer, at one end, a loop (31) is provided which is covered by the winding with contiguous turns (32).

Phase I (fig 11)
We then pass the end (30) of the covering thread in the loop (31), then we pull on the free top (14), which reduces the loop (31) and passes the end (30) under the covering carried out. The protruding end (30) is then cut.

 A very coherent tensile damper assembly has thus been formed, forming an elongation limiter, but nevertheless having little resistance to longitudinal compression.

Phase T (Figures 12 and 13)
On this assembly designated by the general reference (35), by means of the end (14) of the loop (31), a fourth filiform element is fixed in the middle, namely a braid with a square or round section (40) obtained by a six-plaiter with two ends, having a core of stainless steel wire 8 / 100th of a millimeter in diameter and a covering in the same polyester thread as the thread (12) of FIG. 3.

 The free end is then cut (14).

 With one of the two ends of the braid (40) (see FIG. 13), a winding is carried out with contiguous turns in an anticlockwise direction from the knotting point of this braid (40) to in the middle and over the other end (41).

Phase K (Figure 14)
When one arrives in the middle of the winding, a loop (46) ten centimeters long is placed in monocrine (45) one millimeter in diameter, parallel to the end (41). We continue the wrapping by hand over this monocrine loop (45).

 At the end of covering, the free end (42) of the end (40) is introduced into the mud (46).

 The protruding end of the loop (46) is pulled until the free end of the end (40) is brought into contact with the last turn of the covering of this fourth element (40).

 The winding direction (50) of the braid (40) is opposite to that of the previous winding (32), that is to say the opposite of clockwise. This operation is detailed in Figures 15 to 17.

 Finally, pull on the single-strand loop (45) until the loop (46) is completely reduced and the free end (42) is blocked, then the end (42) is cut almost flush with the loop (46), and we forcefully extracts the loop (46). In a variant, in order to stiffen the assembly more strongly, this last covering operation is repeated by reversing the winding direction by means of the other end (41). A new layer (51) is thus spared, fig. 15, 16 and 17.

 Finally (Figure 17), by pulling, the loop (46) is completely extracted.

The end (41) of the square braid is blocked under the last layer (51), and is cut flush with its outlet (52).

 The assembly obtained is placed in an oven heated to 150 ° C. to cause the polyester threads to shrink.

 The synthetic vertebral ligament thus obtained is then placed in a sterile sachet ready for use.

 Alternatively, when the diameter of the eyelets (1,1 ') is greater than the diameter of the loops (18,19) of Figure 9, it may be advantageous to make the primary winding in a single loop and no longer in eight as shown in Figures 3 to 5, the other phases remaining identical.

The method according to the invention has many advantages. We can cite:
- the absence of investment in equipment,
- great regularity of operations which are simple, therefore
easily reproducible,
- great strength in traction and especially in compression
longitudinal,
- excellent buckling resistance with respect to the axis
longitudinal.

 In this way, this set can be successfully used for the manufacture of the vertebral ligaments.

 It can also be used for other applications, such as in particular fittings.

Claims (8)

 1 / Method for producing a rigid and flexible textile assembly, having a high tensile strength and good resistance to compression and buckling, characterized in that it consists:  A - to wind a first flexible filiform textile element (12) around two parallel axes (10,11) by forming a plurality of continuous flanges  B - to tie (15) the two ends of the filiform textile element by enclosing the plurality of loops formed, so as to produce an eight-shaped assembly while mixing free ends (14,16);  C - to withdraw the two parallel axes (10,11);  D - to be fixed on this knot (15) by means of the free ends (14, 16) the end (21) of a second filiform textile element (20);  E - to surround in coils this second element (20) on the two loops (18,19) of the assembly in eight, so as to cover it with a protective sheath;  F - to fix the free end (22) of the second filiform textile element (20) on the knot of the figure-eight assembly by means of the free ends (14);  G - to insert in each of the two loops (18,19) of this new set in eight a rigid eyelet (1,1 ');  H - to wind on the textile assembly formed in a helix and on several layers a third filiform textile element (30) formed of parallel strands, taking care, at least in the penultimate layer, to form a loop (31) then partially covered by said winding  I - to cut one of the two strands (14) at the level of the sheath formed, then to pull on the cleared strand until appreciable reduction of the mouth (31) according to H;  J - to fix on this new assembly by means of the strand released along I and in its middle, a fourth filiform textile element (40);  K - to wind this fourth filiform textile element (40) in contiguous turns on the assembly according to I, but in the opposite direction from the winding according to H, and taking care to release the end of the strand released according to I;  L - to insert the end (41) of this fourth filiform textile element (40) into the loop (46) of a grommet, then to pull on the strand released according to I, so as to insert one of the ends (41) of the fourth textile element (40) under the winding along K and to wind the other end in another layer in the opposite direction to the previous one and to introduce this second end in the loop of the grommet, until it disappears and locks this end under the loops of the winding;  M - and finally, to cut the free end (41) flush with the assembly produced.  2 / A method according to claim 1, characterized in that the filiform textile elements (12,20,30,40) are made of a retractable and high tenacity polyester textile yarn and in that the assembly according to M is then retracted in the oven .  3 / Method according to one of claims 1 and 2, characterized in that the first (12) and the third elements (30) filiform textiles are constituted by a multi-filamentary synthetic yarn.  4 / Method according to one of claims 2 and 3, characterized in that the second filiform element (20) is a flat braid and in that the fourth filiform textile element (40) is a braid with a square section.  5 / Method according to one of claims 1 to 4, characterized in that one of the filiform textile elements (12,40) is assembled with a metal wire detectable by fluoroscopy.  6 / A method according to claim 1, characterized in that the flanges according to A already take the shape of an eight.  7 / A method according to claim 1, characterized in that the two eyelets (1) according to G are made of metal and have on one side a concave opening (3) and on the other a convex opening (6) and on the edge a concave housing (5) intended to receive the end of the ends of the figure-eight assembly according to F.  8 / Synthetic vertebral ligament obtained by the implementation of the method according to one of claims 1 to 7.