SHEDDING METHOD AND APPARATUS USING AIR PRESSURE

Abstract

A method and an apparatus for producing a woven material from tape-like warps and wefts are disclosed, comprising a warp supply source for tape-like warps; a shed forming device to form a shed by said warps; a weft insertion device for inserting tape-like weft in the shed formed by said warps; and a take-up device for taking-up the produced woven material. Each of the warps extend in warp paths between the warp supply source and the take-up device. Further, the shed forming device comprises an air pressure system arranged to apply pressure on the face of at least some of the warps in an intermediate position of the warp paths, between the warp supply source and the take-up device, the applied air pressure being sufficient to displace said at least some warps in essentially the thickness direction of the tape-like warps.

Claims

1. An apparatus for producing a woven material from tape-like warps and wefts comprising: a warp supply source for tape-like warps; a shed forming device to form a shed by said warps; a weft insertion device for inserting tape-like weft in the shed formed by said warps; and a take-up device for taking-up the produced woven material; wherein each of the warps extend in warp paths between the warp supply source and the take-up device, and wherein the shed forming device comprises an air pressure system arranged to apply pressure on the face of at least some of the warps in an intermediate position of the warp paths, between the warp supply source and the take-up device, the applied air pressure being sufficient to displace said at least some warps in essentially the thickness direction of the tape-like warps.

2. The apparatus of claim 1, wherein the air pressure for performing shedding is vacuum/suction air pressure.

3. The apparatus of claim 1, wherein the shed forming device is arranged to form the displaced warps into a two-arm form.

4. The apparatus of claim 2, further comprising a warp feeding system, for release of lengths of warp from the warp supply.

5. The apparatus of claim 4, further comprising a controller arranged to control the release of lengths of warp in synchronization with the operation of the shedding device.

6. The apparatus of claim 2, wherein the vacuum pressure system comprises a plurality of shedding ducts to exert a suction action on individual warps.

7. The apparatus of claim 6, wherein the vacuum pressure is controllable to displace the warps without physically contacting the shedding ducts.

8. The apparatus of claim 6, wherein the shedding ducts are controllable individually or in groups to exert displacing vacuum/suction pressure to displace a select number of the warps at a time.

9. The apparatus of claim 6, wherein shedding ducts are arranged on both sides of the warps and controlled selectively, thereby enabling displacement of the warps in two directions, both being in the thickness direction of the warps.

10. The apparatus of claim 6, wherein at least some of the shedding ducts are moveable in a direction towards and away from the warps.

11. The apparatus of claim 6, wherein the shedding ducts are further provided with a guard, preventing dragging of warps into the shedding duct.

12. A method for producing a woven material from tape-like warps and wefts comprising: providing tape-like warps from a warp supply; forming a shed by said warps; inserting tape-like weft in the shed; and taking up the produced woven material; wherein each of the warps extend in warp paths between the warp supply source and the take-up device, and wherein the forming of the shed comprises applying air pressure towards the face of at least some of the warps in an intermediate position of the warp paths, between the warp supply source and the taking-up, the air pressure being sufficient to displace said at least some warps in essentially the thickness direction of the tape-like warps.

13. The method of claim 12, wherein vacuum/suction air pressure is applied towards faces of warps directed in a first direction for a first set of warps, and towards faces of warps directed in a second direction, opposite to the first direction, for a second set of warps, thereby forming a symmetric shed.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0059] The present inventions relating to VSM and VSS are illustrated in the following drawings by way of examples wherein:

[0060] FIG. 1 exemplifies the relative arrangements of the main components of VSS, namely vacuum generator, vacuum distribution system, and Shed Activator with Shedding Ducts.

[0061] FIGS. 2a and 2b exemplify shed formation through use of VSS.

DETAILED DESCRIPTION OF THE RELEVANT EMBODIMENTS

[0062] In the following detailed description, relevant embodiments of the present inventions are described. It is to be understood that features of the different embodiments are changeable and may be combined in different ways, unless anything else is specifically indicated. It may be also noted that, for the sake of clarity, the dimensions of certain things illustrated in the drawings may differ from the corresponding dimensions in real-life implementations of the invention. Even though in the following description numerous specific details are set forth to provide a more thorough understanding of the present inventions, it will be apparent to one skilled in the art that the present inventions may be practiced with modifications to the specific details. In other instances, the commonly known constructions and/or functions to a person skilled in the art are not described in detail to not obscure the present inventions.

[0063] A VSS, based on VSM of the present invention, is described in reference to FIGS. 1 and 2. For ease of representation the asymmetric shed formation in the usual horizontal weaving format is considered here, although any other weaving format, such as vertical and angular formats, could be similarly considered by a skilled person. Further, the VSS having multiple secondary vacuum ducts is illustrated for broader understanding. A person skilled in the art will be able to perform shedding with the single secondary vacuum duct as well.

[0064] FIG. 1 shows an arrangement of the various preferred parts of a VSS. A weaving apparatus (4), for weaving material using warp tapes and weft tapes, is housed in a weaving hall (9). A vacuum generator (1), preferably situated outside of the weaving hall (9), is connected through primary vacuum conveyor (2) to a distributor (3) which is, for example, attached to the side of a weaving apparatus (4). One end of a secondary vacuum conveyor (5) is attached to a primary vacuum port of the vacuum distributor (3). The other end of the secondary vacuum conveyor (5) is preferably attached suitably to the first connector (6) of the modularly attached Shed Activator (7). At convenient a side of the Shed Activator (7) is attached a suitable Shedding Duct (8). A series of Shed Activators (7) with the Shedding Ducts (8) are modularly interconnected through respective connectors (6) of each Shed Activator (7). All these indicated components are suitably supported and fixed on the weaving apparatus (4).

[0065] FIGS. 2a and 2b show the tape-weaving apparatus (4) in its side view together with the relevant parts (6, 7, 8) of the novel Vacuum Shedding System. For ease of explanation, production of plain weave is considered. Serially arranged warp tapes are supplied from either one or more than one set of sources. While the former may be exemplified by one beam on which all the side-by-side serially arranged warp tapes occur, the latter could be, for example individual spools which are serially arranged side-by-side in suitable number of groups. In FIG. 2 is indicated an arrangement wherein two groups of warp tapes (11 and 12) are sourced from corresponding spools (11a and 12a) which are positioned, for example in two different vertical planes to practically facilitate their accommodation and access on the weaving machine. Warp tapes (11 and 12), individually drawn from their sources (11a and 12a), are respectively guided over the rolls (11b and 12b) and pass through the respective warp-feeding arrangements (11c and 12c). All the serially occurring warp tapes of the two groups are then commonly drawn between the nipping rollers (17a and 17b) of the fabric take-up system. The ends of the warp tapes are finally attached to the fabric winding roller (not shown). Back and front paired rollers (13 and 14) respectively are suitably positioned in the linear warp path to define the geometry of the sheds to be produced for weaving tape-like warps and wefts. Warp-feeding units (11c and 12c) alternately reciprocate between their respective set positions (A and B) to feed the warp tapes of one group towards the shedding system (6, 7, 8) to successively form sheds (15) for enabling insertion of the weft tapes (16) to obtain a woven material (18) of plain weave pattern. In the indicated arrangement, the fabric-fell position is nearer to a side of the paired rollers (14) which faces the Shedding Ducts (8). Instead of paired rollers (14), some other suitable arrangement could be also considered, e.g. paired bars/plates.

[0066] Formation of shed (15) by the Vacuum Shedding System is as follows. Referring to FIG. 2a, each required Shed Activator (7), through their connection to the secondary vacuum duct (6), are operated whereby the corresponding attached Shedding Ducts (8) directs suction of air from the vicinity of the facing warp tapes (11) concerned. When the warp tapes (11) are fed by the warp-feeding arrangement (11c) towards the direction of shedding system (6, 7, 8), the vacuum pressure in the Shedding Ducts (8) draws and displaces the fed warp tapes (11) towards itself and causes the warp tapes (11) to smoothly curve into a two-arm form (11d and 11e). Such a displacement of the warp tapes (11) in a curving two-arm form (11d and 11e), in relation to the linearly occurring warp tapes (12), results in the formation of shed (15). Each operating Shedding Duct (8) supports the corresponding warp tape in the curving two-arm (11d and 11e) form through vacuum pressure and generates tension in them. After weft (16) has been inserted in shed (15) and positioned at fabric-fell, the fabric take-up rollers (17a and 17b) are operated to advance the just-created woven material (18) which is simultaneously wound on the fabric roll (not shown). The edge of the just-inserted weft (16) facing the Shedding Ducts (8) now re-establishes the fabric-fell position. As the advancement of woven material (18) happens, the vacuum supply in the Shed Activator (7) is switched off from secondary vacuum duct (6) causing the curving two-arms (11d and 11e) of warp tapes (11) to lose support and hence get released from Shedding Ducts (8) and level with the non-displaced warp tapes (12) as all the warp tapes are pulled by the take-up rollers (17a and 17b).

[0067] In the next weaving cycle, as shown in FIG. 2b, each of the required Shed Activator (7), through their connection to the secondary vacuum duct (6), are operated whereby each of the attached Shedding Ducts (8) directs suction of air from the vicinity of the warp tapes (12) concerned. As the warp tapes (12) are fed by the warp-feeding arrangement (12c) towards the direction of shedding system (6, 7, 8), the vacuum pressure in the Shedding Ducts (8) draws the fed warp tapes (12) towards itself and causes the warp tapes (12) to smoothly curve into a two-arm form (12d and 12e). Such a displacement of the warp tapes (12) in a curving two-arm form (12d and 12e), in relation to the linearly occurring warp tapes (11), results in the formation of a new shed (15). Each operating Shedding Duct (8) supports the curving two-arms (12d and 12e) through the vacuum pressure and generates tension in them. After weft (16) has been inserted in shed (15) and positioned at fabric-fell, the fabric take-up rollers (17a and 17b) are operated to advance the just-created woven material (18) which is simultaneously wound on the fabric roll (not shown). The edge of the just-inserted weft (16) facing the Shedding Ducts (8) now re-establishes the fabric-fell position. When the advancement of woven material (18) happens, the vacuum supply from in the Shed Activator (7) is switched off from secondary vacuum duct (6) causing the curving two-arms (12d and 12e) of warp tapes (12) to lose support and hence get released from Shedding Ducts (8) and level with the non-displaced warp tapes (11) as all the warp tapes are pulled by the take-up rollers (17a and 17b).

[0068] Alternate displacement of warps tapes (11 and 12) for shed formation by the described VSM and VSS, in conjunction with other required sequential weaving operations, in a cyclical manner accords continuity to the production of woven material (18).

[0069] A person skilled in the art will see now numerous possibilities in the manner VSM can be performed and VSS can be organized and operated. For example, Shed Activator (7), together with its Shedding Duct (8), can be either reciprocated or extended-contracted between two points—one, to be close to the level warp tapes, and the other to be at the necessary distance supporting the smoothly curving two-arm form of the displaced warp tapes for creating the shed for safe passage of the weft. This way the vacuum pressure can be highly effectively utilized besides imparting greater controlled movement to the warp tapes during shed formation. This idea of reciprocating Shed Activator (7)-Shedding Duct (8) could be also implemented in an oscillating manner whereby they are made to swing back and forth in synchronization with feeding of the warp tapes. Another approach would be to render the construct of the secondary vacuum duct (6), Shed Activator (7) and Shedding Duct (8) suitable for a rotary type arrangement. For further functional improvements of VSS, the following could be considered: (i) periodic self-cleaning by automatic discharge of filters with collected fibres, (ii) its self-aligning with warp tapes during weaving process, e.g. through vision cameras or sensors, (iii) quick-adapting constructs whereby the same Shed Activator (7) and/or Shedding Duct (8) can be used for performing shedding for a range of different warp tape widths, (iv) Shedding Ducts (8) equipped with air or spring or soft-material cushions to ensure that the warp tapes make a gentle touch/contact with it, (v) Shed Activator (7) and/or Shedding Duct (8) equipped with sensors for detecting missing or deformed warp tapes and halting the weaving apparatus for rectification, and (vi) Shed Activator (7) and/or Shedding Duct (8) incorporating manual/automatic vacuum regulator, air-suction noise absorbers, individual light indicators for drawing attention to rectify operational problems etc.

[0070] A person skilled in art will be now also able to apply the Air Shedding Method and develop a suitable Air Shedding System on lines similar to VSM and VSS for weaving with tape-like warps by blowing air.

[0071] Such and other obvious modifications must be considered within the scope of the present invention, as defined by the appended claims. It should be noted that the above-mentioned embodiments illustrate rather than limit the invention, and that those skilled in the art will be able to design many alternative embodiments without departing from the spirit and scope of the appended claims. In the claims, any reference signs placed between parentheses shall not be construed as limiting to the claim. The word “comprising” does not exclude the presence of other elements or steps than those listed in the claim. The word “a” or “an” preceding an element does not exclude the presence of a plurality of such elements. Further, a single unit may perform the functions of several means recited in the claims.