Field of Invention:

The present invention relates to 3D Woven fabric and its method of production. In particular, the 3D woven orthogonal fabric comprises of multiple layers of warp yarns interlacing with multiple sets of wefts in orthogonal as well as angular directions forming plain or other weave patterns like twill, drill, satin etc with high mechanical strength.

Background of Invention:

The normal weaving process on any loom, shuttle or shuttle less has three primary mechanisms. The three primary mechanisms, which are in three orthogonal directions, are shedding, weft insertion and beating. The warp threads are laid in longitudinal direction, are in large number and in sheet form. The number of threads depends upon the width of the fabric and warp density. Fabric is formed at one end of the warp in the longitudinal direction. The other end of warp sheet is continually being released from multithread package (beam) or from individual packages (creel), as the fabric is being formed. Shedding mechanism splits this warp thread in two sheets. This shedding mechanism is in right angle to the warp sheet. All the threads are drawn through the thread eyes of held wires. The movement is achieved through cam motion, dobby or jacquard. The weft, the horizontal thread interlacing the warp threads, is inserted between the two warp sheets formed by the shedding mechanism. This weft insertion is in the width direction of the warp sheet and is perpendicular to the shedding mechanism. The weft thread is inserted by shuttle in conventional looms and by gripper, rapier, airjet or water jet in recent looms. The laid weft is beaten and positioned in the fabric formed at one end of warp sheet. The shed is changed so that all or some of the threads change their position from existing shed to the other shade. A new weft is inserted and beating done: A fabric when produced using a single layer warp results in a sheet-like woven material and is referred to as a woven 2D fabric. The thickness of the fabric is small compared to the length and width. Multiple layered fabrics can be produced on 2-d waving system. Warp threads pass from one layer to other to bind the layers. However, there is a limitation to the number of layers. Also there is no interlacement with the warp in thickness direction of fabric.

Attempts have been made in the prior art to overcome the above mentioned problems:

US6338367, US6431222, US6186185 and US6889720 by Khokar Nandan discloses a method to interlace a multilayer warp and two orthogonal sets of weft to produce a thoroughly interlaced woven 3D fabric construction.

However all of the above mentioned prior arts have following disadvantages:

Large opening of warp sheet (in few centimetres) for shuttle or rapier to pass is required in above developments

The weft carriers have to travel longer distance; longer weft is laid in the fabric which is much larger than the length of weft required in the fabric.

> Weft carrier rubs against the warp, can break the migrating warp threads.

/ The shed has to be changed for every orthogonal weft entry. Leno weave cannot be produced.

The present invention provides a method to produce orthogonal interlaced 3- dimentional fabric with multiple sets of warp in one direction and multiple wefts inserted in both orthogonal directions.

The present invention provides solution to overcome all of the above disadvantages as follows: In this invention the opening is reduced (in few millimetres). This affects the working of the system as bellow

• The strain on the warp is reduced • Smaller converging angles of warp to fell of the fabric. So ease in beat up. Less tension variation between warp near centre of the fabric and near edges of the fabric

• Shorter distance between weft entry plane to fell of the fabric so

smaller weft movements in the warp while beating so less abrasion on warp and weft

In this invention, the weft carriers do not touch the warp while laying the warp.

In this invention, one shed formed by rotating the disks, both the orthogonal sets of wefts can be entered. Also, the invention makes leno weave possible.

Thus with the help of this new system, production of 3-D fabric make the product affordable and less complicated and which will be useful in aviation, automobile and other industrial use.

Objects of the Invention:

An object of this invention is to make available a highly integrated 3D woven orthogonal interlaced fabric with different weave constructions for use in technical applications like aviation, automobiles etc.

Another object of this invention is to provide a novel rotating disk type shedding method to enable interlacement of three orthogonal sets of yarn: one set of multilayer warp and two orthogonal sets of weft.

Yet another object of present invention is to make available a highly integrated 3D woven orthogonal interlaced fabric with different weave constructions manufactured using the novel rotating disk type shedding mechanism. Summary of the Invention:

The present invention provides a rotating disk type shedding mechanism to manufacture a highly integrated 3D woven orthogonal interlaced fabric with different weave constructions for use in applications like aviation, automobile etc. The novel rotating disk type shedding method is summarized as below:

A array of rotating disk is arranged horizontally onto the weaving machine surface. The warp threads are passed through four thread guides embedded on the surface of each disk present in the array. With the help of rapiers, the weft threads are inserted in the gaps between the four thread guides forming a hair pin like looped weft which is locked by a locking needle and locking thread, and are held in position with the help of crow bar. The weft is then beaten by open reed. In this way the wefts in both orthogonal axes are laid and beaten up. The disks in the array are then rotated by 90° angles around their respective centers. A new shed is formed. Now, the wefts are again inserted in both orthogonal axes. After rotating the disks, the warp threads change their position in such a way that next weft inserted form interlacement with the warp in respect to previously laid wefts. This way layer by layer fabric is formed alternatively in both the orthogonal axis.

The present invention has the below advantages:

1. The rotating disk shedding system provides an added advantage of insertion of both orthogonal sets of wefts without changing the shed. The shed can be changed by rotating the disks in the array, for the insertion of second set of wefts.

2. The insertion of wefts in space between the thread guides is done by use of rapiers. The rapiers of small section are guided throughout the path. The rapier can be made thinner by using better and stiffer materials. Thinner the rapier, the space between the guides hence disk size can be reduced. The converging angles from weft entry to fell of the fabric can be reduced limiting it to parallel weaving.

3. The rapiers do not touch the warp so warp breaks are avoided. 4. The rotating disk shedding system forms rigid selvedges on all the faces of the fabric even though the rapiers are been used for the weft insertion.

5. The present invention also allows insertion of wefts in angular directions adding to the mechanical strength of the fabric formed.

6. The warp threads from adjacent layers can be exchanged giving effect like multilayer 2- d fabric.

7. The warp threads and weft threads in all the weft directions can form 4-end leno weave. The leno weave is one of the strongest weave and is difficult to weave. It gives strength and rigidity to the fabric.

8. The fabric can be woven in large solid square section, thick rectangular slab or in engineering sections like angle or T section or channel or I-beam or rectangular tubular or other sections.

Brief Description of the drawings:

Figure 1 describes the construction of the rotating disk type shedding system in accordance with the present invention

Figure 2A-2D explains the interlacement mechanism betweens yarns while weaving 3D fabric using the said rotating disk type shedding system

Figure 3A-3L shows a step by step process of formation of 3D orthogonal interlaced fabric of a typical plain weave construction, according to the present invention

Figure 4 shows the insertion of wefts threads in 45 degrees angular direction using said rotating disk type shedding system

Figure 5 shows an isometric view of the process of formation of 3D orthogonal interlaced fabric of a typical plain weave construction Following Table No. 1 describes the legends used in the drawings and their description

Table No. 1

Detailed description of the drawings:

Description of the drawings given herein below is illustrative only and should not be construed to limit the scope of the present invention in any manner. Picking end refers to the end from which the weft threads are inserted in the space between the thread guides embedded on surface of rotating disk.

Receiving end refers to the end opposite to the picking end i.e. the end opposite to the end from which the weft threads are inserted. Figure 1 describes the construction of the rotating disk type shedding system in accordance with the present invention.

Figure 1A shows the isometric view of the rotating disk type shedding system of the present invention. The said system comprises of a disk (1) which can rotate around its axis, and has 4 thread guides (2,3,4,5) embedded onto the disk surface through which the warp threads (6) can pass.

Figure IB shows the top view representation of the rotating disk type shedding system with possible rotation of the disk (1) around its axis. The disk (1) has an extra thread guide at the center through which an extra non-interlacing warp thread (7) passes. The warp threads (6) as can be seen in the figure, lie in Z-axis, while the 2 orthogonal set of wefts are inserted in the X and Y- axis in between the thread guides (2,3,4,5).

Figure 2A-2D explains the interlacement mechanism betweens yarns while weaving 3D fabric using the said rotating disk type shedding system.

The wefts (TX1, TX2) and (TY1 , TY2) are inserted in between the thread guides

(2,3,4,5) along the X-axis and Y-axis direction respectively as shown in Figure 2A. The disk (1) is then rotated by 90° around its axis as is shown in figure 2B. The wefts (TX1 and TX2) thus gets interlaced with the warp threads in thread guides (2,3) and (5, 4) respectively. Also, the wefts (TY1 and TY2) gets interlaced with the warp threads in thread guides (2,5) and (3,4) respectively as shown in figure 2C. Now, the next set of weft threads (TX3, TX4) and (TY3, TY4) are again inserted in between these thread guides (2,3,4,5) along the X-axis and Y-axis direction respectively as is shown in figure 2D. Thus, the weft threads (TX1, TX3) interlace with the warp threads in thread guides (2,3); while the weft threads (TX2, TX4) interlace with the warp threads in thread guides (5,4) respectively. Similarly, the weft threads (TY1, TY3) and (TY2, TY4) gets interlaced with their respective warp threads, thus in continuation process forming a consecutive layer of fabric in X and Y-axis direction respectively.

Figure 3A-3L shows a step by step process of formation of 3D orthogonal interlaced fabric of a typical plain weave construction, in accordance with the present invention.

Referring to figure 3 A, an array of rotating disks (1) is shown to be arranged in a plain. The number of disks (1) in the array depends upon number of required warp ends width wise and breadth wise. The warp threads (6) are passed through the thread guides (2,3,4,5) embedded on the surface of each disk (1) in the array. Insertion of Wefts in Y-axis direction:

The rapiers in Y- axis direction (8) are of a small section with a leading end having a thread eye, carrying a weft thread in Y- axis direction (10). These rapiers in Y- axis direction (8) are then inserted in Y-axis direction in the space in between the thread guides (2,3,4,5) embedded on the surface of each disk ( 1 ) in the array in such a way that they form U loops of the weft threads at the receiving end, as is shown in figure 3B. A locking thread needle (9) for weft threads in Y- axis direction (10) is then placed perpendicular to the rapiers in Y-axis direction (8) and in the same plane as that of the rapiers.. A locking thread (1 1) for wefts in Y-axis direction (10) is placed in the eye of the locking thread needle (9), and then the locking needle (9) is inserted into the U loops of the wefts threads thus forming a locking thread loop at the receiving end as shown in figure 3C. A crow bar (12) to hold the locking thread loop is inserted in the locking thread loop, and the locking thread needle (9) is moved backwards outside the fabric, as is shown in figure 3D. Now, as the wefts in Y-axis direction (10) have been inserted in U loop or hair pin type loop and are locked at the receiving end by means of a locking thread (11) and crow bar (12), the rapiers in Y-axis direction (8) are moved back outside the fabric, as shown in figure 3E. The fabric is then beaten to fell.

Insertion of Wefts in X-axis direction:

Now, the same process is followed for insertion of wefts in X-axis direction. The rapiers in X- axis direction (13), carrying a weft thread in X- axis direction (15) are then inserted in X-axis direction in the space in between the thread guides (2,3,4,5) embedded on the surface of each disk (1) in the array in such a way that they form U loops/ hair pin type loop of the weft threads at the receiving end, as is shown in figure 3F. A locking thread needle (14) having a locking thread (16) is placed perpendicular to the rapiers in X-axis direction (13) and in the same plane as that of the rapiers. The locking thread needle (14) is inserted into the U loops/ hair pin type loops of the weft threads thus forming a locking thread loop at the receiving end, as shown in figure 3G. A crow bar (17) to hold the locking thread loop is inserted in the locking thread loop, and the locking thread needle (14) is moved backwards outside the fabric, as is shown in figure 3H. Now, as the wefts in X-axis direction (15) have been inserted in hair pin form and are locked at the receiving end by means of a locking thread (16) and crow bar (17), the rapiers in X-axis direction (13) are moved back outside the fabric, as shown in figure 31. The fabric is then beaten to fell.

The key advantage of the present invention over the prior patents is that one can insert two sets of orthogonal wefts in one shed formation. Usually, once the wefts in X-axis direction are inserted, one needs to change the shed before inserting wefts in Y-axis direction. The present invention allows insertion of both orthogonal sets of wefts- in X-axis and Y-axis directions, before changing the shed for inserting another two sets of orthogonal wefts.

Now, all the disks (1) in the array are then rotated by 90° around their respective axis, and the shed is changed as is shown in figure 3 J. Referring to figure 3K, once again the second set of wefts is inserted in X-axis and Y-axis directions using the same procedure as described above such that consecutive wefts interlace each warp thread forming plain weave in X-axis and Y-axis directions. Thus, at the end of whole process, a highly integrated 3D woven orthogonal interlaced fabric of plain weave construction is thus formed, as is shown in figure 3L. The present system also leads to the formation of closed selvedges (18) which are same as the shuttle loom selvedge, at the picking ends; as well as to the formation of firmly thread locked selvedges (19) at the receiving ends.

Additional non interlacing warp threads (7) can be drawn through the central holes on the disks. Additional non-interlacing wefts can also be inserted in X-axis and Y-axis directions in between the whole process, to produce a highly integrated 3D fabric structure having a high mechanical performance, and adding to the fiber percentages when to used as reinforcements in composite structures.

The present invention also allows formation of fabric having shape of hollow section with thread locked selvedges, since the invention allows insertion of both orthogonal set of weft threads in one shed formation. Usually forming thread locked selvedges requires insertion of locking thread with the help of locking needle inside the fabric which is not possible in case of weaving fabric having shape of hollow sections. The present invention addresses this problem by allowing insertion of threads perpendicular to the inserted weft threads to lock them forming thread locked selvedges without the use of locking needle.

Figure 4 shows the insertion of wefts threads in 45 degrees angular direction using said rotating disk type shedding system

Other than the orthogonal insertion of weft threads, the present system also allows the entry of wefts in 45° angular directions. The disks (1) in the array can be rotated by 45° around its axis, as shown in figure 4A.

Referring to figures 4B and 4C, the set of rapiers (20, 22) can be used to insert the set of weft threads (21, 23) in 45° angular directions respectively without changing the shed. Then again all the disks (1) in the array are rotated by 90° , and the second set of weft threads are inserted in angular directions, so that the weft threads interlace with their respective warp threads in that direction. Additional non-interlacing yarns can also be inserted in angular directions using the same process thus adding to the strength of the fabric. Figure 5 shows an isometric view of the process of formation of 3D orthogonal interlaced fabric of a typical plain weave construction

Isometric view of the rapier entry has been shown for better understanding of the present process of making available a highly integrated orthogonal 3D fabric for use in technical applications like aviation etc. The rapiers enter in the space between the thread guides (2,3,4,5) onto the disk (1) without touching the warp threads (6) present in these thread guides (2,3,4,5). As the rapiers have a very small cross section, the distance between the thread guides (2,3,4,5) can be as small as possible. In other embodiment of present invention, the said disks (1) in the horizontal array of disks (1) may be rotated by 180 degrees and wefts can be inserted in X and Y- axis directions leading to the formation of fabric of 4-end leno weave type construction with high mechanical strength. In another embodiment of present invention, selective disks (1) in the horizontal array may be rotated and wefts can be inserted in X and Y-axis directions leading to formation of fabric with variety of different weave constructions like 2/1, 4/1, twill, satin etc. In yet another embodiment of present invention, if disks (1) in horizontal array are not rotated for all subsequent weft thread insertions in X and Y-axis directions, a non-interlaced NOOBED structure of fabric may be formed.

In yet another embodiment of present invention, a selective NOOBED and interlaced structures can be formed by selectively rotating one set of the disks (1) in array while keeping the other set of disk (1 ) in the array in an un-rotated state. Thus, the present invention provides an affordable system and a process to make available a highly integrated 3D woven orthogonal interlaced fabric with different weave construction to be used as reinforcement in the manufacture of composites that can be used in various applications like aviation, automobile, space technology and many other industrial applications.