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Title:
A CIRCULAR LOOM, A METHOD TO MAKE TUBULAR WOVEN FABRIC OF COMPOSITE WEAVE, AND A TUBULAR WOVEN FABRIC OF COMPOSITE WEAVE
Document Type and Number:
WIPO Patent Application WO/2022/090865
Kind Code:
A1
Abstract:
The present invention relates to a circular loom and a method for manufacturing of a tubular woven fabric of composite weave using a circular loom, and a fabric of composite weave, i.e. a combination of plain and leno weave. The fabric has a portion of plain weave and some portion of doup weave. An inventive circular loom (1) is provided with a main plate (9) that supports shed forming means for doup weave and plain weave. This is made feasible by provision of a first cam plate (2) and a second cam plate (3), each of which have an irregular surface on which a first cam lever (6) and a second cam lever (7) operate. The composite weave is made possible by the provision of a doup rocking lever assembly (8) that connects the first cam lever (6) to the first shedding means (4) which produces a doup weave and by provision of the second cam lever (7) which is connected to second shedding means (5) to produce a plain weave.

Inventors:
LOHIA GAURAV (IN)
Application Number:
PCT/IB2021/059609
Publication Date:
May 05, 2022
Filing Date:
October 19, 2021
Export Citation:
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Assignee:
LOHIA CORP LTD (IN)
International Classes:
D03C7/00; D03D37/00; D03D3/02; D03D49/00
Domestic Patent References:
WO2016205849A12016-12-29
Foreign References:
EP1967623A22008-09-10
US4424836A1984-01-10
Attorney, Agent or Firm:
TASE, Vijay (IN)
Download PDF:
Claims:
Claims:

1. A circular loom (1) to manufacture a tubular woven fabric of composite weave characterised in that said circular loom (1) comprises: a main plate (9) including shed forming means and weft fdling means is mounted within a frame, said shed forming means, and said weft fdling means being driven by an electric motor disposed below the main plate (9); a tubular fabric haul-off means mounted on said frame above the main plate

(9) driven by an independent drive mechanism which is in synchronization with a main drive; a hollow hub (15) mounted on said main plate (9), said hub being hollow from inside through which a main shaft (10) passes, said main shaft (10) being a solid rod and supported by a plurality of bearings affixed to said hollow hub (15) to allow a free rotation of the main shaft (10) about an axis (34); a first cam plate (2) and a second cam plate (3) connected to said main shaft

(10) through said bearings, said first cam plate (2) being provided with control curve for doup type shed formation and said second cam plate (3) being provided with a control curve for plain weave shed formation; a plurality of shedding means, namely first shedding means (4) and second shedding means (5) being arranged around the periphery of the main plate (9); a first cam lever (6) mounted on the periphery of said main plate (9), and a doup rocking lever assembly (8) connects said first cam lever (6) to said first shedding means (4); a second cam lever (7) mounted on the periphery of said main plate (9) with one end of said second cam lever (7) being connected with said second shedding means (5) while another end being connected with the cam profile of said second cam plate (3) respectively; a pair of creels disposed on both sides of said apparatus; an even number of shuttles mounted on a reed (13), said reed being an annular shuttle guide member, so that they can travel along the reed (13); a weaving ring (16) circular in shape and having a plurality of connecting arms (17), one end of which is connected to the weaving ring (16) and another end being connected to said reed (13); wherein a number of warp tapes from a plurality of packages mounted rotatably and symmetrically with respect to the axis (34) feed said warp tapes to said creels, and weft tapes taken out from the respective shuttles are fabricated with warp tapes to form a tubular fabric of the composite weave of desired patterns.

2. The circular loom as claimed in claim 1, wherein said first shedding means (4) comprises a first belt (22) which is passed through a pair of pulleys (30) mounted respectively on an upper and a lower block (19, 20), said upper block (19) being mounted on said reed (13) with a bracket (21) and said lower block (20) being mounted on said main plate (9) using mechanical joint; said first belt (22) is further connected with said first cam lever (6).

3. The circular loom as claimed in claim 1 wherein said first cam lever (6) comprises a first swinging arm (6 A), a first jockey lever (6B), a first roller (6C), a second roller (6D) and a connector (35), wherein said first swinging arm (6 A) and first jockey lever (6B) are connected at a junction X, such that it is capable of swivelling about the junction; and wherein said first jockey lever (6B) is mounted on the main plate (9) and are arranged at the periphery of it.

4. The circular loom as claimed in claim 1, wherein said first swinging arm (6 A) at one end is connected to the first belt (22) via connection between said connector (35) and a first vertical facilitator (22D), while at the other end a pair of rollers, namely first roller (6C) and second roller (6D) are connected to said first cam plate (2).

5. The circular loom as claimed in claim 1, wherein the connection at the first and second-cam-plate (2, 3) end is facilitated by the means of rollers (6C, 6D, 7C, 7D), between which the respective cam profiles he, and wherein said first and second cam plates (2, 3) are provided with irregular profile to provides to-and-fro motion to said first and second cam levers (6,7) about point X&Y, which in turn provide to-and-fro motion to said first and second shedding means (4, 5) respectively.

6. The circular loom as claimed in claim 1, wherein a set of first number of first shedding means (4) are placed after a set of second number of second shedding means (5).

7. The circular loom as claimed in claim 1, wherein the number of said shuttles is four, said first number is four and said second number is five.

8. The circular loom as claimed in claim 1, wherein the number of said shuttles is four, and wherein a set of five first shedding means (4) are placed at two positions, each set being placed after a set of thirteen second shedding means (5).

9. The circular loom as claimed in claim 1, wherein a total number of thirty six shedding means (4, 5) are used for weaving a fabric (29), and a set of 2 first shedding means (4) is placed after every set of eleven second shedding means (5), and there is provided a region (Z) sandwiched between the set of first shedding means (4), where a restrictor (36) is provided to block warp tapes from entering into the weaving ring.

10. The circular loom as claimed in claim 9, wherein said restrictor (36) is of L- or U- shape or a square block or a rectangular plate.

11. The circular loom as claimed in claim 3, wherein the number of the first jockey lever (6B) is equal to the number of the first belt (22).

12. The circular loom as claimed in claim 1, wherein said wefts are fabricated with warps sequentially opened on both the upper and lower sides of the respective shuttles by shedding means.

13. The circular loom as claimed in claim 1, wherein said connection between said connecting arm (17) and said reed (13) is of a mechanical type such as bolting, screwing, or riveting.

14. The circular loom as claimed in claim 1, said first cam plate (2) is connected to a ring (14) with a plurality of joints (32), said ring (14) being made of material flexible enough to change the shape of said ring from circular to oval by tightening of an adjustment screw (33).

15. The circular loom as claimed in claim 2, said set of first belts (22) comprise same number of first outer and first inner strands (22A, 22B) which are fixedly arranged lengthwise in a space between the confronting horizontal planes of said upper and lower block (19, 20), wherein each of said first inner strands (22B) and first outer strand (22A) have an eye through which said warp tapes pass.

16. The circular loom as claimed in claim 15, wherein the first inner strand (22B) of said first belt (22) comprises a comb like first guide means (22G) through which said warp tape passes, and a set of prongs (23) shaped structural members each having a thread eye disposed on the free end thereof for the shedding guidance of a warp thread, wherein said warp tape passes between each prong (23).

17. The circular loom as claimed in claim 16, wherein a displacement means or first lateral facilitator (22E) engages preferably with a first inner strand (22B) of a first belt (22) after each shedding motion to bring about the instantaneous lateral relative counter displacement.

22 The circular loom as claimed in claim 1, wherein said doup rocking lever assembly (8) comprises a roller (8A) mounted on a swivel bracket (8B) with a swivel bush (8C) and a torsion spring (8D), said roller (8A) being in contact with the ring (14) which pushes the swivel bracket (8B) against the torsion spring (8D) mounted on a swivel bush (8C) resulting in the swinging motion of swivel bracket (8B), and wherein said swivel bracket (8B) has sticker arm, which imparts the lateral displacement to the first inner strand (22B) through a rocking lever (25). The circular loom as claimed in claim 1, wherein the profile of the first cam plate (2) and the profile of the second cam plate (3) are different in construction. The circular loom as claimed in claim 1, wherein the even number of shuttles being ‘n’, an equal number of shedding means all together (4 and 5) are used, and wherein if ‘x’ number of first shedding means (4) are used, then ‘n-x’ number of second shedding means (5) are used. A method of manufacturing a tubular woven fabric of composite weave on the circular loom as claimed in claims 1 to 20, characterised in that said method comprises the steps of: making an arrangement with said first and second belts (22,31) for threading of warp yam/tape (28) through said second belt (31); threading a cross end warp (27) and ground end warp (26) through said first belt (22); subjecting both ground end warp (26) and cross end warp (27) ends to a positive shedding motion using a pair of strands (22A,22B); imparting lateral displacement to said cross end warp (27) on one side of said ground end warp (26) by a ring (14); shifting said cross thread (27) on the opposite side of said ground end warp (26) at a next shedding to form a shed after said cross end warp (27) passing beneath said ground end warp (26);

23 repeating the shedding motion of said cross end warp (27), thereby forming a combination of doup (11) and plain (12) weave. A woven fabric made on the circular loom as claimed in claims 1 to 20 and using the method as disclosed in claim 21, characterised in that said fabric has multiple weave patterns made from warp and weft yam as desired. The woven fabric as claimed in claim 22, wherein said multiple weave patterns include plain weave (12) and a doup weave (11). The woven fabric as claimed in claim 23, wherein said fabric comprise an area of plain weave (12) where warp yam is absent.

24

Description:
A CIRCULAR LOOM, A METHOD TO MAKE TUBULAR WOVEN FABRIC OF COMPOSITE WEAVE, AND A TUBULAR WOVEN FABRIC OF COMPOSITE WEAVE

Field of invention:

The present invention relates to a circular loom and a method for manufacturing of a tubular woven fabric of composite weave, i.e. a combination of plain and leno weave, in a circular loom and rapid conversion system.

Background of Invention:

Tubular packaging bags formed from woven fabrics of a plain weave structure utilizing slit fdm tapes of synthetic resins, such as polypropylene and polyethylene resins or synthetic resin strands, such as multifilament yams or cords of synthetic resins, as warps and wefts have been widely used for transportation and storage of granules, such as grains, sugar fertilizers and synthetic resin pellets. This is because these bags are strong and light in weight. These bags can be made from a tubular fabric produced by using a circular loom having a high weaving efficiency for the manufacture of the tubular fabric to be formed into these bags. However, tubular bags with the plain weave do not provide enough aeration for storage and transportation of fruits or vegetables.

For storage and transportation of fruits or vegetables like potatoes or onions, doup type weave is preferred as it produces light weight tubular fabric with suitable ventilation of product. In such tubular fabric, two neighbouring warp threads no longer he parallel next to each other. Instead, the so-called doup thread loops around or crosses the other warp thread, here referred to as the ground thread, in such a way that the weft threads are bound in place and unable to slip. There are systems available for producing such doup fabrics also on circular looms, in particular for the manufacture of tubular fabrics made from narrow plastic strands for the fabrication of sacks. Further, with higher demand of packaging heavy weight goods with branding on package, there is requirement of tubular fabric having some portion of plain weave for strength to withstand the heavy weight of goods, and remaining portion of doup weave for aeration. Also, due to unprecedented change in market demand, there is a requirement of agile circular loom which can produce tubular fabric having in part a doup segment and in part a plain weave segment as per need.

To cater to the above rapid changing market requirement, the present invention provides for a circular loom and method to allow manufacturing of tubular fabric having composite weave using the circular loom, i.e. it has segments of plain weave and doup weave along the fabric circumference. Also, it has provision, for rapid changing in number of segment or portion of plain weave or doup weave pattern along the fabric circumference.

Objectives:

The main objective of the present invention is to provide a circular loom for manufacturing of tubular fabric of composite weave having portion of plain weave and some portion of doup weave.

Another objective of the present invention is to provide a method for manufacturing of tubular fabric of composite weave having portion of plain weave and some portion of doup weave

Further, objective of the present invention is to provide method for rapid change of weave from plain weave to doup weave in tubular fabric as per market demand.

Another objective of the present invention is to produce only plain weave or only doup weave fabric at reasonable production rate.

Brief description of figures:

Figure 1 shows the circular loom of the present invention Figure 2 shows a schematic movement of shedding means for doup weaving

Figure 2A shows first belt for doup weaving

Figure 3 shows a schematic movement of shedding means for plain weaving

Figure 3A shows the second belt for plain weaving

Figure 4 shows the weave pattern of fabric created using circular loom of the invention

Figure 5 shows first example of arrangement of the circular loom of the invention with combination of first shedding and second shedding means

Figure 5A pattern of weave obtained by the circular loom setup as per first example

Figure 6 shows second example of arrangement of the circular loom of the invention with combination of first shedding and second shedding means

Figure 6A pattern of weave obtained by the circular loom setup as per second example

Figure 7 shows third example of arrangement of the circular loom of the invention with combination of first shedding and second shedding means

Figure 7A pattern of weave obtained by the circular loom setup as per third example

Figure 8 shows rocking motion of the rocker lever

Figure 8A shows enlarged view of the rocker lever assembly Summary Of Invention:

The present invention relates to a circular loom and a method for manufacturing of a tubular woven fabric of composite weave, i.e., a combination of plain and leno weave, in a circular loom and rapid conversion system. The circular loom according to the present invention to manufacture a tubular woven fabric of composite weave comprises a main plate (9) onto which shed forming means and weft filling means are mounted within a frame and which are driven by an electric motor disposed below the main plate (9). There is a tubular fabric haul-off means mounted on the frame above the main plate (9) and driven by an independent drive mechanism which is in synchronization with a main drive. A hollow hub (15) which is hollow from inside is mounted on said main plate (9). A main shaft (10) passes through the said hollow hub (15). The main shaft (10) is a solid rod which is supported by a plurality of bearings affixed to the hollow hub (15) to allow a free rotation of the main shaft (10) about an axis (34). A first cam plate (2) and a second cam plate (3) connected to said main shaft (10) through said bearings, said first cam plate (2) being provided with control curve for doup type shed formation and said second cam plate (3) being provided with a control curve for plain weave shed formation. A plurality of shedding means, namely first shedding means (4) and second shedding means (5) are arranged around the periphery of the main plate (9). Further, a first cam lever (6) mounted on the periphery of said main plate (9), and a doup rocking lever assembly (8) connects said first cam lever (6) to said first shedding means (4). A second cam lever (7) mounted on the periphery of said main plate (9) with one end of said second cam lever (7) is connected with said second shedding means (5) while another end is connected with the cam profile of said second cam plate (3) respectively. A pair of creels are disposed on both sides of said circular loom and an even number of shuttles are mounted on a reed (13) that is an annular shuttle guide member, also known as a reed (13), so that the shuttles can travel along the reed (13). A weaving ring (16) is provided. It is circular in shape and having a plurality of connecting arms (17) one end of which is connected to the weaving ring (16) and another end being connected to the reed (13). The number of warp tapes from a plurality of packages mounted rotatably and symmetrically with respect to the axis (34) feed said warp tapes to said creels, and weft tapes taken out from the respective shuttles are fabricated with warp tapes to form a tubular fabric. The circular loom (1) of the invention can be customised and operated in following combination to produce a desired fabric with different weave arrangements.

List of parts:

1. Inventive circular loom

2. First cam plate (cam plate for doup weave)

3. Second cam plate (cam plate for plain weave)

4. First shedding means (shedding means for doup weave)

5. Second shedding means (shedding means for plain weave)

6. First cam lever (cam lever for doup weave)

6A. First swinging arm

6B. First jockey lever

6C. First roller

6D. Second roller

7. Second cam lever (cam lever for plain weave)

7A. Second swinging arm

7B. Second jockey lever

7C. Third roller

7D. Fourth roller

8. Doup rocking lever assembly

8A. Roller

8B. Swivel bracket

8C. Swivel bush

8D. Torsion spring

9. Main plate

10. Main shaft or vertical shaft

11. Doup weave

12. Plain weave

13. Reed 14. Ring

15. Hollow Hub

16. Weaving ring

17. Connecting arms

18. Vertical support

19. Upper block

20. Lower block

21. Bracket

22. First belt

22A. First outer strand

22B. First inner strand

22C. First strap

22D. First vertical facilitator

22E. First lateral facilitator

22F. First guide

22G. Second guide means

23. Prong

24. Pivot

25. Rocking lever

26. Ground end warp

27. Cross end warp

28. Warp yam/tape

29. Fabric

30. Pulley

31. Second belt

31 A. Second outer strand

3 IB. Second inner strand

31C. Second strap

3 ID. Second vertical facilitator

3 IE. Second guide

3 IF. Second guide means 32. Joint

33. Adjustment screw

34. Axis

35. Connector

36. Restrictor

Description of invention:

In the circular weaving loom (1) of the present invention, an even number of shuttles (not shown) are mounted on an annular shuttle guide member, also known as a reed (13), so that these shuttles can travel along the reed (13). Engaging means to be engaged with corresponding shuttles, respectively, such as press rollers, are moved along the reed (13). Each shuttle is pressed by the corresponding engaging means (not shown) and is propelled along the reed (13) Weft yam/tape taken out from the respective shuttles are fabricated with warp yam/ tape sequentially opened on both the upper and lower sides of the respective shuttles by belts and a plain weave tubular fabric is thus formed. The take-up drive and motor are mounted on the top frame while the warp let off drive and motor are mounted on both side frames (not shown in figures). All system drives have individual motors and are controlled through central electronic control unit.

In the circular loom (1) of the present invention as illustrated in FIG. 1, a main plate (9) including shed forming means and weft filling means is mounted within a frame, and the shed forming means, and filling means are driven by an electric motor disposed below the main plate (9) through a power transmission mechanism (not shown). Tubular fabric haul-off means mounted on the frame above the main plate (9)is driven by an independent drive mechanism (not shown) connected to the haul- off means such that it is in synchronization with main drive. Warps are fed to a pair of creels disposed on both sides of the circular loom (1) of the invention. Number of warps fed depends on the type of weave and size of the fabric. A plurality of packages mounted rotatably for feeding warps feed the warps symmetrically with respect to the axis (34). The tubular fabric formed by the weaving operation is upwardly taken out by the haul-off means and guided to winding means (not shown).

Figure 1 shows the circular loom (1) of the invention which comprises of stationary main plate (9) onto which hollow hub (15) is mounted. The main plate (9) can be metallic or non-metallic or made of any cast material which can bear the load of the components mounted onto it. The hollow hub (15) is constructed in such a way that it is hollow from inside through which a main shaft (10) passes. The main shaft (10) is a solid rod which is supported by a plurality of bearings affixed to the hollow hub (15) such that a free rotation of the main shaft (10) occurs about the axis (34). Such rotation of the main shaft (10) by the drive motor (not shown) is responsible for rotating the main plate (9) and corresponding cam plates (2,3).

The cam plates, namely a first cam plate (2) and a second cam plate (3), are connected to the main shaft (10) through bearings. The first cam plate (2) is being provided with control curve for doup type shed formation and the second cam plate (3) is being provided with a control curve for plain weave shed formation.

The circular loom (1) of the present invention having the above-mentioned structure, as shown in FIG. 1, further comprises of plurality of shedding means, namely first shedding means (4) and second shedding means (5). These shedding means (4, 5) are arranged around the periphery of the main plate (9) of the circular loom (1) of the invention in a circular fashion. The pattern of the placement of the shedding means (4,5) is configured as per the requirement of the weaving patterns.

As a first example shown in figure 5, in case of a four shuttle circular loom (1) of the present invention, a total number of thirty six shedding means is used for weaving a fabric (29), then a set of four first shedding means (4) are placed after every set of five second shedding means (5) to get a perfect weaving pattern as shown in figure 5A

As a second example shown in figure 6, in the case the said circular loom (1) as defined above, is provided with a set of five first shedding means (4) at two positions, then two positions can be altered as per requirement, and same are placed after every set of thirteen second shedding means (5) to get a perfect weave pattern as shown in figure 6A.

A shown in figure 7, 7A another pattern of weaving can be obtained from the said loom (1) of the present invention, wherein combination of doup and plain weaving is shown. Figure 7 shows the circular loom (1) of the invention, which as an example, is a four shuttle circular loom (1), where a total of thirty six shedding means is used for weaving a fabric (29), following which a set of 2 first shedding means (4) are placed after every set of eleven second shedding means (5) and the region Z is sandwiched between the set of first shedding means (4) . The region Z is the area where the warp tapes does not enter into the weaving ring for weaving pattern. Thus, the region Z only contains weft tapes from the shuttle in circular fashion such that there is not vertical weaving happens. The region Z is thus obtained by blocking the weaving ring (16) by a restrictor (36). The restrictor (36) can be of any shape such that L shape or U shape or a square block or rectangular plate such that it restricts warp tape to enter at the region Z. Such setup will produce a perfect weaving pattern as shown in figure 7A.

The above examples are just illustrations considering one configuration of the circular loom (1) of the present invention, such that a total of thirty-six shedding means is used. But the circular loom (1) of the invention has an ability of rapidly converting the shedding means system such that the number of shedding means can be altered as per the customer requirement to obtain the desired weaving pattern. Thus, to generalise the shedding means system of the circular loom (1) of the present invention, for even number of shuttles in loom (1) wherein shuttles provide weft tapes, the ‘n’ number of shedding means are used. If the ‘x’ number of first shedding means (4) are used to obtain doup weave (11) pattern, then ‘(n-x)’ number of second shedding means (5) are used to obtain plain weave (12).

Thus the above stated configuration can be altered as per the requirement of weaving patterns such that combination of the weave pattern can be obtained.

The shed forming mechanism comprises a plurality of cam levers (6, 7) mounted on to the peripheral of the main plate (9) such that the one end of the first and second cam lever (6,7) is connected with the first and second shedding means (4,5) while another end is connected with the cam profile of the first and second cam plate (2,3) respectively. The connection at the first and second cam-plate (2, 3)-end is facilitated by the means of rollers (6C,6D,7C,7D), between which cam profile lies. The irregular profile on the cam plates (2,3) provides to and for motion to the cam lever (6,7) about point X&Y, which in turn provides to-and-fro motion to the first and second shedding means (4, 5) respectively.

Further, the circular loom (1) of present invention comprises of weaving ring (16) onto which tubular fabric is woven. The weaving ring (16) is circular in shape and can be of different diameter depending upon the width of the tubular fabric desired. A plurality of connecting arms (17) is provided, one end of which is connected to the weaving ring (16) and another end is connected to the reed (13). The connection can be of mechanical type such as by bolting, screwing, or riveting.

The first cam plate (2) is connected to a ring (14) via plurality of joints (32) and is adjusted by an adjustment screw (33). The ring (14) is constructed in such a way that it is flexible enough to change it shape from circular to oval when tightened with the adjustment screw (33). A doup rocking lever assembly (8) is connected at the periphery of the reed (13) at one end and with the vertical support (18) on the other end as shown in figure 8, 8A.

In the system of the present invention, both the shredding means (4,5) are placed such that the portion of the fabric which is to be plain weaved, the corresponding second shedding means (5) is provided in front of it while the portion at which doup weaving is required, first shedding means (4) is provided as shown in figures 5,5A,6,6A.

Figure 2 shows the movement of first shedding means (4) for doup weaving. First shedding means (4) comprises of first belt (22) which is passed through a pair of pulleys (30). These pulleys (30) are mounted on the upper and lower block (19,20) such that they provide smooth movement to the pulleys (30) and thereby the first belt (22) can be moved in vertical up and down fashion easily with much less to negligible friction. The upper block (19) is mounted on the reed (13) via bracket (21) while the lower block (20) is mounted on the main plate (9). The first belt (22) is further connected with the first cam lever (6). The first cam lever (6) comprises of first swinging arm (6A), first jockey lever (6B), first roller (6C), second roller (6D) and a connector (35). The first swinging arm (6 A) and first jockey lever (6B) can connect at a junction X, such that it is capable of swivelling about the junction. The said first jockey lever (6B) is mounted on the main plate (9) and are arranged at the periphery of it. The number of the first jockey lever (6B) is always equal to the number of the first belt (22) used in the circular loom (1) of the present invention. On other hand first swinging arm (6A) at one end is connected to the first belt (22) via connection between the connector (35) and first vertical facilitator (22D), while at the other end, a pair of rollers, namely first roller (6C) and second roller (6D) are provided which are connected to the first cam plate (2).

The set of first belts (22) when arranged in the circular fashion in the circular loom (1) of the invention due to the irregular profile on the first cam plate (2), a to-and-fro vertical movement of first belt (22) is seen which often occurs in succession such that a vertical movement of the first belt (22) is reversed to the vertical movement of the adjacent first belt (22). The same number of outer and inner strands (22A, 22B) are held by each of the first belt (22), which are fixedly arranged lengthwise in a space between the confronting horizontal planes of the upper and lower block (19, 20). Since the shape of the first cam plate (2) is designed with respect of the movement of the first belt (22), such that a fully open shed is formed when the warps are passed through the eyes of the corresponding inner and outer strands (22B,22A), respectively, a shed forming a doup weave structure can be produced.

The first shedding means (4) further comprises of a doup rocking lever assembly (8) which in turn comprises of a roller (8A) which is mounted on the swivel bracket (8B) connected via swivel bush (8C) and torsion spring (8D). Due to oval construction of the ring (14) and due to circular motion of the ring (14) at one instance the roller (8 A) will be in contact with the ring (14) which pushes the swivel bracket (8B) against the torsion spring (8D) mounted on a swivel bush (8C) resulting in the swinging motion of swivel bracket (8B). The swivel bracket (8B) has a striker arm, which imparts the lateral displacement to the first inner strand (22B) through rocking lever (25).

In the circular loom (1) of the present invention as previously described, in required portion for doup weave, the said first belt (22) can also be made from slit belt strands, for which for approximately each first belt (22), an endless belt extends over each of the rotating supported pulleys (30) on the upper and lower block (19,20) respectively. The first inner strand (22B) and the first outer strand (22A) of the first belt (22) mounted on a first strap (22C), each carry thread eyes or first guide (22F) through each of which a warp thread of one or the other warp-thread sheets is drawn. The generation of an oppositely phased up-and-down reciprocating motion of said outer and inner strand (22A,22B) of said first belt (22), permits the previously mentioned change-of-shed motion on the two warp-thread sheets to take place. For this change- of-shed motion, it is known that preferably said first inner strand (22B) is fastened tightly below said thread eye thereof to a so-called first swinging arm (6A), said first swinging arm (6A) being slid vertically up and down or more preferably rotates about an axis (X).

Projecting from said first swinging arm (6 A) are first and second roller (6C, 6D) which is guided against a corresponding cam surface of the associated first plate cam (2) mounted centrally and rotatable with the main shaft (10) of the circular loom (1) of the invention.

In order to form doup weave pattern it is necessary each time after a weft passage, to produce a preliminary tension on said warp threads by the displacement of said first belt (22) relatively against each other in the one or the other direction, which causes said warp threads, at the alternating motion thereof, to jump each time onto the other side of the warp thread, which consequently results in a doup fabric portion as shown in Figure 4.

In such a doup fabric, the cross end warp (27) and the ground end warp (26), and two neighbouring warp threads, are bound in a manner so that they are unable to slip, with several weft threads. Consequently, it is necessary that for the reciprocal arrangement of the cross end warp (27) to run lengthwise to the ground end warp(26) and two neighbouring warp threads to produces a doup weave (11) portion. The displacement means, or first lateral facilitator (22E) engages on preferably the inner strand (22B) of a first belt (22) after each shedding motion to bring about the instantaneous lateral relative counter displacement. Furthermore, the warp threads of one strand of said first belt (22) are in each case guided freely by second guide means (22G) to bring about the shedding and, on the other strand, to bring about a side change, as is subsequently illustrated in greater detail.

Accordingly, the first inner strand (22B) of said first belt (22) comprises of second guide means (22G) which has comb like structure through which said warp threads passes. It further comprises of the prongs (23) which a teeth shaped structural members each having a thread eye disposed on the free end thereof for the shedding guidance of a warp thread. The said warp passes between each prongs (23) or the freely guided warp threads to bring about the side change.

When, for example, there results an upward movement of said first inner strands (22B), and a downward movement of said first outer strands (22A) and vice-a- versa due to the so-called Zero-position of said first belt (22), at which position said warp threads are found in the weaving plane, the cross end warp (27) lies first to the left of the ground end warp (26). After a change of movement, by which said first inner strand (22B) in a downward position and said first outer strand (22A) is in an upward position, and after weft insertion has taken place, a displacement of the comb-like second guide means (22G) of said first inner strand (22B) takes place to the right. Thereby, said warp threads receive a preliminary tensioning that causes said warp threads, at the next zero-passage, to change sides by jumping over, which illustrates the complete change of motion. Thereby, said cross end warp (27) lies to the right of said ground end warp (26). At the next movement, said comb like second guide means (22G) of said first inner strand (22B) can regain its other (left) extreme position under the effect of the torsion spring (8D), which again leads to a change of side of said warp threads, and so forth.

The same result is achieved when the lateral displacement of the comb-like second guide means (22G) on the first belt (22) or more precisely on the first inner strand (22B) takes place by way of a rocker bearing. For this purpose, a swivelling rocking lever (25), having striking means, and being horizontal around an axle, extends below each first inner strand (22B), said striking means being swivelled alternately under each first inner strand (22B) upon each downward movement thereof, whereupon said comb-like second guide means (22G) are tilted in each case from one side to the other and vice versa. Said swivelling of said rocking lever (25) takes place by way of ring (14) movement on the first plate cam (2) of the circular loom (1) the invention.

Moreover, in the circular loom (1) has the strands (22A,22B) constructed in the previously described manner by strap or belt strands, which can, with slight alteration, be employed in the same manner. In this case, the comb-hke second guide means (22G) on said first inner strand (22B), for the displacement thereof, be supported by a horizontal guide or also by a rocker bearing (not shown) with displacement means according to the afore mentioned embodiments.

Since plural pairs of the above-mentioned paired first belts (22) are annularly arranged along the periphery of the main plate (9) adjacently to one another, these paired first belts (22) can create successive sheds of identical shape with rotation of the first cam plate (2). Accordingly, if a plurality of shuttles, for example, four shuttles, is propelled by the respective shuttle propelling mechanisms held by the supporting member, synchronously with formation of these sheds, a tubular fabric portion of a plain weave structure can be formed.

Figure 3 showcase movement of second shedding means (5) for plain weaving. Second shedding means (5) comprises of plurality of second belt (31) which are also arrange in a set. The mounting of the second shedding means (5) is identical to the first shedding means (4) such that it comprises of two pulleys (30) one at each end of the endless second belt (31). The said pulleys (30) are connected onto the upper block (19) and lower block (20) such that upper block (19) is affixed to the main plate (9) and lower block (20) is mounted on the reed (13) via bracket (21). The second belt (31) is further connected with the second swinging arm (7A) by a connector (35) at one end. The other end of the second swinging arm (7A) is connected to the second cam plate (3) via third and fourth roller (7C,7D) and the said second swinging arm (7A) is capable of rotating about Y connected to the second jockey lever (7B). The irregular profile on the second cam plate (3) provides a to-and-fro vertical movement of second belt (31) which often occurs in succession such that a vertical movement reversed to the vertical movement of the second belt (31) is given to the other or adjacent second belt (31). The same number of second guiding means (3 IF) are held by each of the second belt (31) or more preferably to the second inner and second outer strand (3 IB, 31 A), are fixedly arranged lengthwise in equal space. Since the shape of the second cam plate (3) is designed with respect to the second belt (31), so that a fully open shed is formed when the warps yam/tape (28) are passed through the eyes of the corresponding second belt (31), respectively, a shed forming a plain weave structure can be produced by rotation of the second cam plate (3).

Figure 3 A shows a second belt (31) comprising of a second strap (31C) connecting the inner and outer strands (3 IB, 31 A) between which lies a second guiding means (3 IF) for guiding the warp yam/tape (28) tape for plain weaving. The warp yam/tape (28) tape passes through the second guide (3 IE) such that it provides a smooth movement to the tape. The second belt (31) further comprises a second vertical facilitator (3 ID) affixed to the second inner strand (3 IB) which is connected to the second swinging arm (7A) such that the swivelling action of the second swinging arm (7A) provides a vertical to-and-fro motion to the second belt (31) and plain weaving occurs.

Further, the profile of the first cam plate (2) and the profile of the second cam plate (3) is different in construction such that the vertical to-and-fro movement of the first belts (22) and second belts (31) are different.

The circular loom (1) of the present invention can be customised and operated in following combination to produce a desired fabric with different arrangements/pattems as described below:

As an example, weaving of fabric is done on a four-shuttle loom which requires 576 warp tapes and 36 no. of belts. The weft tape is governed by the 4 no. of shuttles used.

• For plain weaving, all the belts used as showed in figure 3A. The said plain weave (12) can be obtained by configuring the said circular loom (1) such that the doup rocking lever assembly (8) is made inactive by removing it from the circular loom (1) and replacing the first shedding means (4) with second shedding means (5). The replaced shedding means must be connected with the second cam plate (3), to obtain a plain weave (12). • For doup weaving, all the belts used as shown in figure 2A. The said doup weave (11) can be obtained by replacing second shedding means (5) with first shedding means (4) and adding doup rocking lever assembly (8). The replaced shedding means must be connected with the first cam plate (2), to obtain a doup weave (11).

• For mixed weaving like doup plus plain, a combination of belts showed in figures 2 A and 3 A is to be used. Such that the connection of the first shedding means (4) is with the first cam plate (2) and the connection of the second shedding means (5) is with the second cam plate (3)

The following steps are involved in manufacturing of a tubular woven fabric of composite weave, i.e., a combination of plain and leno weave, in a circular loom and conversion system as disclosed below:

• In a circular loom (1) an arrangement with the belts (22,31) is made such that threading of warp yam/ tape (28) is done through second belt (31).

• Further, cross end warp (27) and ground end warp (26) are threaded through the first belt (22)

• Subjecting both ground end warp (26) and cross end warp (27) ends to a positive shedding motion using a pair of strands (22A, 22B)

• Achieving the lateral displacement of the cross end warp (27) on one side of said ground end warp (26) by a ring (14)

• Shifting said cross end warp (27) on the opposite side of said ground end warp (26) at a next shedding to form a shed after said cross end warp (27) passes beneath said ground end warp (26)

• Repeating the shedding motion of said cross end warp (27)

• Alternatively, after a required patch of doup fabric plain weaving occurs due to the alternate position of second belts (31).

• Thus, the fabric (29) is obtained with combination of doup and plain weave. For rapid conversion, the position of the first belts (22) and second belts (31) are changed.

From the foregoing description , a circular loom of the present invention also enables the efficient production of a tubular fabric (29) with partial doup weave (11) portion and partial plain weave (12) portion as shown in Figure 4, with the steps as described herein before, being particularly suitable to allow circular looms to be changed over without great effort and expenditure. While the above description contains much specificity, these should not be construed as limitation in the scope of the invention, but rather as an exemplification of the preferred embodiments thereof. It must be realized that modifications and variations are possible based on the disclosure given above without departing from the spirit and scope of the invention. Accordingly, the scope of the invention should be determined not by the embodiments illustrated, but by the appended claims and their legal equivalents.