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Title:
CARPET MANUFACTURING METHOD AND ASSEMBLY, YARN MARKING DEVICE, AND COMPUTER PROGRAM
Document Type and Number:
WIPO Patent Application WO/2013/070072
Kind Code:
A2
Abstract:
In a carpet manufacturing method, for a plurality of yarns each having a length, a plurality of marks are provided on each yarn at selected locations along the yarn. In the carpet manufacturing method and in a carpet manufacturing assembly, each yarn is stored on or in an associated storage, and fed from its associated storage to a carpet manufacturing apparatus. For each yarn, the marks on the yarn are detected upstream of the carpet manufacturing apparatus. On the basis of the detection of the marks, the uptake of the yarn by the carpet manufacturing apparatus is controlled, where after, in the carpet manufacturing apparatus, the yarns are processed to form at least part of a carpet.

Inventors:
HEERES ROBERT JAN (NL)
Application Number:
PCT/NL2012/050782
Publication Date:
May 16, 2013
Filing Date:
November 07, 2012
Export Citation:
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Assignee:
INTERFACE EUROP MFG B V (NL)
International Classes:
D05B47/00; D05B49/00; D05C15/16
Domestic Patent References:
WO2000027532A12000-05-18
Foreign References:
US6283053B12001-09-04
US6439141B22002-08-27
US6502521B22003-01-07
US6508185B12003-01-21
Attorney, Agent or Firm:
Mertens, H.V. (GE Rijswijk, NL)
Download PDF:
Claims:
CLAIMS

1. A carpet manufacturing method, comprising:

providing a plurality of yarns (108) each having a length;

storing each yarn (108) on or in an associated storage;

feeding each yarn (108) from its associated storage to a carpet manufacturing apparatus (306); and

processing, in the carpet manufacturing apparatus (306), the yarns (108) to form at least part of a carpet,

the method further comprising:

providing a plurality of marks (202, 204, 206, 208, 210; 212, 214, 216; 220, 224, 226; 230) on each yarn (108) at selected locations along the yarn (108);

detecting, for each yarn (108), the marks (202, 204, 206, 208, 210; 212, 214, 216; 220, 224, 226; 230) on the yarn (108) upstream of the carpet manufacturing apparatus (306); and controlling, on the basis of the detection of the marks (202, 204, 206, 208, 210; 212, 214, 216; 220, 224, 226; 230), the uptake of the yarn (108) by the carpet manufacturing apparatus (306).

2. The carpet manufacturing method of claim 1 , wherein the step of providing, for a plurality of yarns (108) each having a length, a plurality of marks (202, 204, 206, 208, 210; 212, 214, 216; 220, 224, 226; 230) on each yarn (108) at selected locations along the yarn (108) comprises:

providing an unmarked mother yarn having a length of at least the sum of the lengths of the yarns (108);

providing a plurality of marks (202, 204, 206, 208, 210; 212, 214, 216; 220, 224, 226; 230) on the mother yarn at selected locations along the mother yarn; and

dividing the mother yarn into the yarns (108).

3. The carpet manufacturing method of claim 1 , wherein the step of providing, for a plurality of yarns (108) each having a length, a plurality of marks (202, 204, 206, 208, 210; 212, 214, 216; 220, 224, 226; 230) on each yarn (108) at selected locations along the yarn (108) comprises:

providing an unmarked mother yarn having a length of at least the sum of the lengths of the yarns (108);

dividing the mother yarn into the yarns (108); and providing a plurality of marks (202, 204, 206, 208, 210; 212, 214, 216; 220, 224, 226; 230) on each yarn (108) at selected locations along the yarn (108).

4. The carpet manufacturing method of any of the preceding claims, wherein each yarn (108) comprises a pattern of marks (202, 204, 206, 208, 210; 212, 214, 216; 220, 224, 226;

230), and all yarns (108) have a same pattern of marks (202, 204, 206, 208, 210; 212, 214, 216; 220, 224, 226; 230).

5. The carpet manufacturing method of any of claims 1-4, wherein a distance between consecutive marks along the yarn (108) is constant.

6. The carpet manufacturing method of claims 1-4, wherein a distance between consecutive marks along the yarn (108) is variable. 7. The carpet manufacturing method of claim 6, wherein a distance between consecutive marks decreases along the yarn (108) from a leading end thereof to a trailing end thereof.

8. The carpet manufacturing method of any of the preceding claims, wherein during the step of providing marks (202, 204, 206, 208, 210; 212, 214, 216; 220, 224, 226; 230) on a yarn (108), the yarn (108) is tensioned at a predetermined tension.

9. The carpet manufacturing method of claim 8, wherein the predetermined tension corresponds to a tension of the yarn (108) in the step of detecting, for each yarn (108), the consecutive marks (202, 204, 206, 208, 210; 212, 214, 216; 220, 224, 226; 230) on the yarn (108) upstream of the carpet manufacturing apparatus (306).

10. The carpet manufacturing method of any of the preceding claims, wherein, for a yarn (108), the uptake of the yarn (108) is controlled by:

in association with the step of providing the marks (202, 204, 206, 208, 210; 212, 214, 216; 220, 224, 226; 230) on the yarn (108), storing a first distance between a first mark on the yarn (108) and a second mark on the yarn (108);

at the step of detecting the marks (202, 204, 206, 208, 210; 212, 214, 216; 220, 224, 226; 230) on the yarn (108), measuring a second distance between the first mark on the yarn (108) and the second mark on the yarn (108);

comparing the first distance with the second distance, and

if the first distance is larger than the second distance, decreasing the uptake of the yarn (108); and if the first distance is smaller than the second distance, increasing the uptake of the yarn (108).

1 1. The carpet manufacturing method of claim 10, wherein the second distance is measured by:

determining a first yarn length value at a time of detection of the first mark on the yarn

(108);

determining a second yarn length value at a time of detection of the second mark on the yarn (108); and

determining the second distance by subtracting the first yarn length value from the second yarn length value.

12. The carpet manufacturing method of any of the preceding claims, wherein the detecting of marks (202, 204, 206, 208, 210; 212, 214, 216; 220, 224, 226; 230) on a first yarn (108) and a second yarn (108) is at a same distance from the carpet manufacturing apparatus (306) for the first and the second yarn (108), and wherein the uptake of the first yarn (108) is controlled by comparing a first detection time of a first mark on the first yarn (108) with a second detection time of a second mark on the second yarn (108), and

if the first detection time is earlier than the second detection time, decreasing the uptake of the first yarn (108), or increasing the uptake of the second yarn (108); and

if the first detection time is later than the second detection time, decreasing the uptake of the second yarn (108), or increasing the uptake of first yarn (108).

13. The carpet manufacturing method of claim 12, wherein a speed of at least one yarn (108) is measured, and a difference between a first distance between the first mark and the carpet manufacturing apparatus (306) and a second distance between the second mark and the carpet manufacturing apparatus (306) is determined from said yarn speed and a time difference between the first detection time and the second detection time. 14. The carpet manufacturing method of claim 12, wherein an operating speed of the carpet manufacturing apparatus (306) is measured, and a difference between a first distance between the first mark and the carpet manufacturing apparatus (306) and a second distance between the second mark and the carpet manufacturing apparatus (306) is determined from said carpet manufacturing apparatus operating speed and a time difference between the first detection time and the second detection time.

15. The carpet manufacturing method of claim 1 , wherein the detecting of a mark on a number of the yarns (108) is at the same distance from the carpet manufacturing apparatus (306) for each yarn (108), the uptake of a particular yarn (108) is controlled by comparing a particular detection time of a particular mark on the particular yarn (108) with a mean detection time of corresponding marks on the number of yarns (108), and

if the particular detection time is earlier than the mean detection time, decreasing the uptake of the particular yarn (108), or increasing the uptake of at least one of the other yarns of the number of yarns (108); and

if the particular detection time is later than the mean detection time, decreasing the uptake of at least one of the other yarns of the number of yarns (108), or increasing the uptake of particular yarn (108).

16. The carpet manufacturing method of claim 15, wherein a speed of at least one yarn (108) is measured, and a difference between a distance between the particular mark and the carpet manufacturing apparatus (306) and a mean distance between the corresponding marks and the carpet manufacturing apparatus (306) is determined from said yarn speed and a time difference between the particular detection time and the mean detection time.

17. The carpet manufacturing method of claim 15, wherein an operating speed of the carpet manufacturing apparatus (306) is measured, and a difference between a distance between the particular mark and the carpet manufacturing apparatus (306) and a mean distance between the corresponding marks and the carpet manufacturing apparatus (306) is determined from said carpet manufacturing apparatus operating speed and a time difference between the particular detection time and the mean detection time.

18. The carpet manufacturing method of any of the preceding claims, wherein the uptake of the yarn (108) by the carpet manufacturing apparatus (306) is controlled by adapting a tension in the yarn (108) upstream of the carpet manufacturing apparatus (306). 19. The carpet manufacturing method of claim 18, wherein the uptake of the yarn (108) is decreased by raising a tension in the yarn (108).

20. The carpet manufacturing method of claim 18 or 19, wherein the uptake of the yarn (108) is increased by lowering a tension in the yarn (108).

21. The carpet manufacturing method of any of claims 18-20, wherein the tension in the yarn (108) is adapted by a yarn tension control device (316) arranged upstream of the carpet manufacturing apparatus (306), wherein the yarn tension control device (316) is configured to frictionally engage the yarn (108), and to exert a force on the yarn (108) in the longitudinal direction of the yarn (108). 22. The carpet manufacturing method of any of the preceding claims, wherein the carpet manufacturing apparatus (306) comprises a yarn loop forming device cooperating, for each yarn (108), with an upstream controllable yarn feed roll which in combination provide a controllable yarn feed, and the uptake of the yarn (108) by the carpet manufacturing apparatus (306) is controlled by controlling the yarn feed of the yarn feed roll.

23. The carpet manufacturing method of claim 22, wherein the uptake of the yarn (108) is decreased by decreasing the yarn feed by the yarn feed roll.

24. The carpet manufacturing method of claim 22 or 23, wherein the uptake of the yarn (108) is increased by increasing the yarn feed by the yarn feed roll.

25. The carpet manufacturing method of any of the preceding claims, wherein a mark (212; 220, 222, 224; 230) comprises at least two markings (212a, 212b; 220a, 220b, 222a, 222b, 224a, 224b; 230a, 230b) at spaced longitudinal sections of the yarn (108).

26. The carpet manufacturing method of claim 25, wherein one of the markings of the mark (222, 224, 230) has a length different from another marking of the mark.

27. The carpet manufacturing method of claim 25 or 26, wherein one of the markings of the mark comprises a marking material (1 14) different from the marking material (1 14) of another marking of the mark.

28. The carpet manufacturing method of any of the preceding claims, wherein providing a mark (202, 204, 206, 208, 210; 212, 214, 216; 220, 224, 226; 230) on a yarn (108) comprises applying a marking material (1 14) on a longitudinal section of the yarn (108).

29. The carpet manufacturing method of any of the preceding claims, wherein providing a mark (202, 204, 206, 208, 210; 212, 214, 216; 220, 224, 226; 230) on a yarn (108) comprises spraying a marking material (1 14) on the yarn (108).

30. The carpet manufacturing method of any of the preceding claims, wherein providing a mark (202, 204, 206, 208, 210; 212, 214, 216; 220, 224, 226; 230) on a yarn (108) comprises applying a marking material (1 14) taken from a group of marking materials comprising a liquid marking material and a powdered marking material.

31. The carpet manufacturing method of any of the preceding claims, wherein the marking material (1 14) is applied on the yarn (108) from different directions along its circumference.

32. The carpet manufacturing method of any of claims 29-31 , wherein, after applying the marking material (1 14) on the yarn (108), the marking material is cured by applying a radiation to the marking material.

33. The carpet manufacturing method of claim 32, wherein the radiation comprises at least one of infrared, IR, radiation and ultraviolet, UV, radiation.

34. The carpet manufacturing method of any of the preceding claims, wherein the mark (202, 204, 206, 208, 210; 212, 214, 216; 220, 224, 226; 230) comprises a fluorescent material.

35. The carpet manufacturing method of any of the preceding claims, wherein the mark comprises a metal.

36. The carpet manufacturing method of claim 35, wherein the mark (202, 204, 206, 208, 210; 212, 214, 216; 220, 224, 226; 230) comprises a magnetizable metal.

37. The carpet manufacturing method of any of the preceding claims, wherein the mark (202, 204, 206, 208, 210; 212, 214, 216; 220, 224, 226; 230) comprises a material responsive to UV or IR radiation.

38. The carpet manufacturing method of any of the preceding claims, comprising, directly after providing the mark (202, 204, 206, 208, 210; 212, 214, 216; 220, 224, 226; 230) on the yarn (108), sensing a presence of the mark (202, 204, 206, 208, 210; 212, 214, 216; 220, 224, 226; 230) on the yarn (108).

39. A carpet manufacturing assembly, comprising:

a plurality of storages (302), each configured to store a length of yarn (108) thereon or therein;

a carpet manufacturing apparatus (306) configured to process the yarns (108) to form at least part of a carpet; a feeding device (304) configured to feed each yarn (108) from its associated storage (302) to the carpet manufacturing apparatus (306),

wherein each yarn (108) comprises a plurality of marks (202, 204, 206, 208, 210; 212, 214, 216; 220, 224, 226; 230) at selected locations along the yarn (108), and wherein the carpet manufacturing assembly further comprises:

a detecting device (308) configured to:

- detect, for a yarn (108), the marks (202, 204, 206, 208, 210; 212, 214, 216;

220, 224, 226; 230) on the yarn (108) upstream of the carpet manufacturing apparatus (306); and

- output, for the yarn (108), a yarn mark detection signal (310); a yarn uptake control device (312) configured to:

- receive the yarn mark detection signal (310); and

- control, on the basis of the yarn mark detection signal (310), the uptake of the yarn (108) by the carpet manufacturing apparatus (306).

40. The carpet manufacturing assembly of claim 39, further comprising a marking device (100) configured to provide at least one mark (202, 204, 206, 208, 210; 212, 214, 216; 220, 224, 226; 230) on each yarn (108) at a selected location along its length. 41. The carpet manufacturing assembly of claim 39, wherein the yarn uptake control device is configured to control the uptake of the yarn (108) by:

storing, in a memory (311), a first distance between a first mark on the yarn (108) and a second mark on the yarn (108) determined during marking of the yarn (108);

measuring a second distance between the first mark on the yarn (108) and the second mark on the yarn (108) during detecting the marks of the yarn (108);

comparing the first distance with the second distance, and

if the first distance is larger than the second distance, decreasing the uptake of the yarn (108); and

if the first distance is smaller than the second distance, increasing the uptake of the yarn (108).

42. The carpet manufacturing assembly of claim 39, wherein the yarn mark detection signal (310) comprises a detection time of detecting a mark (202, 204, 206, 208, 210; 212, 214, 216; 220, 224, 226; 230), and wherein the yarn uptake control device (312) is configured to compare a first detection time of a first mark on a first yarn (108) with a second detection time of a second mark on a second yarn (108), and if the first detection time is earlier than the second detection time, to decrease the uptake of the first yarn (108), and/or to increase the uptake of the second yarn (108); and if the first detection time is later than the second detection time, to decrease the uptake of the second yarn (108), and/or to increase the uptake of first yarn (108).

43. The carpet manufacturing assembly of claim 39, wherein the yarn mark detection signal

(310) comprises a detection time of detecting a mark (202, 204, 206, 208, 210; 212, 214, 216;

220, 224, 226; 230), and wherein the yarn uptake control device (312) is configured to compare a particular detection time of a mark on a particular yarn (108) with a mean detection time of corresponding marks on a number of yarns (108), and

if the particular detection time is earlier than the mean detection time, to decrease the uptake of the particular yarn (108), and/or to increase the uptake of at least one of the other yarns of the number of yarns (108); and

if the particular detection time is later than the mean detection time, to decrease the uptake of at least one of the other yarns of the number of yarns (108), and/or to increase the uptake of particular yarn (108).

44. The carpet manufacturing assembly of any of claims 39-43, further comprising:

a yarn tension control device (316) configured to adapt a yarn tension based on a yarn uptake control signal (314) from the yarn uptake control device (312).

45. The carpet manufacturing assembly of claim 44, wherein the yarn tension control device (316) is arranged upstream of the carpet manufacturing apparatus (306), wherein the yarn tension control device (316) is configured to frictionally engage the yarn (108), and to exert a force on the yarn (108) in the longitudinal direction of the yarn (108).

46. The carpet manufacturing assembly of any of claims 39-45, wherein the carpet manufacturing apparatus (306) comprises a tufting apparatus including a yarn loop forming device cooperating, for each yarn (108), with an upstream controllable yarn feed roll which in combination provide a controllable yarn feed, and the uptake of the yarn (108) by the carpet manufacturing apparatus (306) is controlled by controlling the yarn feed of the yarn feed roll based on a yarn uptake control signal (314) from the yarn uptake control device (312).

47. The carpet manufacturing assembly of any of claims 40-46, wherein the marking device comprises at least one nozzle (1 12) configured to provide a marking material (1 14) on a yarn (108).

48. A marking device (100) comprising at least one nozzle (1 12) configured to provide a marking material (1 14) on a yarn (108).

49. The marking device (100) of claim 48, wherein the nozzle (1 12) is configured to spray or jet a marking material (1 14) onto the yarn (108) in a plane at right angles to a longitudinal direction of the yarn (108).

50. The marking device (100) of claim 48 or 49, comprising a duct (102) for conveyance of yarn (108), the duct (102) extending from a first opening (104) at a yarn supply side of the marking device (100) to a second opening (106) at a yarn discharge side of the marking device (100).

51. The marking device (100) of claim 50, comprising a further nozzle (112a) in the longitudinal direction of the duct (102).

52. A computer program enabling the yarn uptake control device (312) of claim 39 to receive the yarn mark detection signals (310), and to control, on the basis of the yarn mark detection signals (310), the uptake of the yarn (108) by the carpet manufacturing apparatus (306).

Description:
Carpet manufacturing method and assembly, yarn marking device, and computer program

FIELD OF THE INVENTION

The invention relates to the field of manufacturing a tufted product, where yarns are fed from a supply to a manufacturing apparatus to form the tufted product, such as (at least a part of) carpets or carpet tiles or other products to cover a bottom or floor area. Herein, such a product will be commonly referred to as a carpet, or a carpet product. The invention relates more specifically to a carpet manufacturing method and assembly. The invention further relates to a yarn marking device, and to a computer program enabling a processor or control device to carry out a controlling according to the invention, in particular a controlling of a device.

BACKGROUND OF THE INVENTION

In a process of manufacturing carpet products, yarns may be used. For the same or for different carpet products, different kinds of yarns may be used. Yarns may be different at least in their material and/or material composition and/or thickness and/or strength and/or color. Also, such yarn properties may vary along the length of the yarn.

In tufting apparatus, rows of needles are arranged, each one arranged for tufting an associated yarn into a support material. The yarns are fed to the respective needles from a storage for each needle, which storage may be a bobbin with a length of yarn wound on it, may be a tube with a length of yarn accommodated therein, or may be any other storage from which a length of yarn for a specific tufting product can be provided. One storage, such as a beam, may comprise more than one yarn. The number of needles in a tufting apparatus generally is several hundreds, for example from 400 to 4,000 needles or more, and thus the number of storages is equally high. The bobbins, tubes, beam or other types of storage may be stored in a frame, rack, creel, or any other type of storage support and arranging structure, e.g. as disclosed in WO 00/27532 A1. Each yarn may be fed or guided from its storage to the tufting apparatus through a tube having a length compensating any difference in path length between different yarns from their storages to the tufting apparatus.

For a particular carpet product, a required length or weight (also resulting in a length) of each yarn is estimated prior to the carpet manufacturing process. This length of yarn is measured and stored on or in a storage. Even if it is intended that each yarn has the same length, still different yarns may in fact have different lengths resulting from inaccuracies while measuring or weighing yarns.

In a carpet manufacturing process, different yarns may be taken up differently or unevenly by a carpet manufacturing apparatus. Reasons for different uptake of yarns have been recognized in an elasticity of the yarns or in varying properties of the yarns along its lengths, (for tufting apparatus) differences in feed rolls or needles of the tufting apparatus, (for tufting apparatus) differences in wear of needles or differences in other parts of the tufting apparatus, internal frictions in the storage(s) and the supply paths of the yarns to a carpet manufacturing apparatus, differences in patterns in a carpet product (e.g. in tufting carpets, different pile heights for different yarns), and so on. Due to varying uptake of yarns, the structure of products obtained by tufting processes varies to some degree. However, since tufted textile products show an irregular surface by nature, irregularities of a few percents in pole lengths do not show to the user in normal use of the carpet product, and could only be shown on a detailed scale.

Differences in originally stored yarn lengths and differences in yarn uptake by the carpet manufacturing apparatus lead to a situation that at a particular point in time during the tufting process, at least a first one of the yarns will be completely or almost completely used up, i.e. the end of the yarn will be approached or reached, while the remaining yarns still have some more length left. Here, great differences between remaining lengths of respective yarns may exist, and will exist in practice.

When this situation arises, a new similar yarn may be spliced to the yarn about to be used up to continue the manufacturing process of the current carpet. The manufacturing process may continue until a next yarn becomes used up and needs to be spliced to a new similar yarn, and so on. Once the carpet is finished, either after a first yarn has been completely or almost completely used up, or before this situation arises since the length of all yarns are greater than needed, it may be decided to cut all yarns and splice a complete new set of yarns to produce a subsequent different carpet product, where remainders of yarns previously used are stored, possibly after having been spliced to other similar yarns and put on or in one storage, for future use.

In fact, since the lengths of the different yarns for a carpet product cannot be controlled, each time a carpet product is finished all yarns must be cut and spliced to a new set of yarns for a subsequent carpet product.

In the manufacturing process described above, numerous problems arise.

From a general perspective, a first problem arises from customer demands nowadays. An ever increasing demand for smaller order sizes (i.e. less area of carpet product) of a particular carpet product can be observed. Customers also require the turnaround times to be low. To comply with such requirements, relatively frequent set-up changes must be made in a carpet manufacturing line. In particular, after finishing a carpet product, a carpet

manufacturing line must be stopped, current yarns must be cut, and new yarns must be spliced to the current yarns. This requires huge amounts of time and manual labor for preparing storages, changing storages, removing storages still containing some length of yarn, splicing of yarns, etc. As it turns out, carpet manufacturing apparatus are increasingly idle in view of the increasing number of set-up changes. The factors of increased manual labor and increased idling of tufting apparatus increase production costs substantially.

A further problem arises when a large quantity of remainders of yarns on or in storages need to be used in future orders efficiently. To organize these remaining quantities of yarns, a physical ordering would be necessary where yarns on or in their corresponding storages are put away in a warehouse such that efficient retrieval is possible. For every storage, a set of information should be kept in a database and updated. However, in practice this would involve such meticulous bookkeeping and warehousing of such large quantities of yarns, that any information gathered may be outdated before it is even stored in the database, the location of the storages may have changed, etc. Therefore, in practice an inefficient use of storages is accepted, and many remainders of yarns are wasted while they cannot be matched to actual orders since they are not available or cannot be traced when the need for them arises. SUMMARY OF THE INVENTION

It would be desirable to provide a carpet manufacturing method that provides for a continuous operation of a carpet manufacturing apparatus. It would also be desirable to reduce a volume of remaining quantities of yarns after use thereof in a production of a carpet product.

To better address one or more of these concerns, in a first aspect of the invention a carpet manufacturing method is provided, comprising: providing, for a plurality of yarns each having a length, a plurality of marks on each yarn at selected locations along the yarn; storing each yarn on or in an associated storage; feeding each yarn from its associated storage to a carpet manufacturing apparatus; detecting, for each yarn, the marks on the yarn upstream of the carpet manufacturing apparatus; controlling, on the basis of the detection of the marks, the uptake of the yarn by the carpet manufacturing apparatus; and processing, in the carpet manufacturing apparatus, the yarns to form at least part of a carpet.

Thus, the present invention proposes to mark lengths of yarns by providing marks on the yarns at selected locations thereof, and to use these marks by detecting them to control the uptake of one or more yarns by the carpet manufacturing apparatus, such as a tufting apparatus. During the uptake of a yarn by the carpet manufacturing apparatus, the yarn is moving, and thereby a mark provided on the yarn is also moving. The yarn may be moved along a detector to detect the mark on the yarn. Accordingly, an uneven uptake of yarns can be compensated for, such that the uptake of the lengths of the yarns for a particular carpet product may be substantially the same. Accordingly, a changeover from one carpet product to a next carpet product can take place at a very well defined point of each yarn, for all yarns at the same time. Thus, already in advance new lengths of yarns may be prepared and spliced to currently processed yarns to provide a continuous manufacturing of subsequent products on a carpet manufacturing apparatus, thereby avoiding idle time of the carpet manufacturing apparatus, and remainders of yarns as a result of the carpet manufacturing process itself can be avoided.

It is noted that a compensation of an uneven uptake of yarn may result in small differences in pole lengths in the carpet product produced by the carpet manufacturing apparatus. However, such differences in practice are similar to the differences in pole lengths experienced from the uneven uptake itself, and do not show to the user in normal use of the carpet product, while the carpet product has an irregular surface by nature. The invention thus takes advantage of the existing process window (caused, inter alia, by the uneven uptake of yarn) to invisibly compensate the uneven uptake of yarn.

In an embodiment of the carpet manufacturing method, the step of providing, for a plurality of yarns each having a length, a plurality of marks on each yarn at selected locations along the yarn may comprise: providing an unmarked mother yarn having a length of at least the sum of the lengths of the yarns; providing a plurality of marks on the mother yarn at selected locations along the mother yarn; and dividing the mother yarn into the yarns. Here, the marked yarns all are produced from the same mother yarn, and thereby are likely to have substantially the same mechanical and dimensional properties. This may considerably reduce differences between different marked yarns, and may facilitate the yarn uptake control. The marking process may be continuous for the mother yarn, where distances between consecutive marks can be controlled accurately. The mother yarn may be kept at a continuous tension during the marking process, which mitigates differences between distances between consecutive marks on the mother yarn, for each length of mother yarn intended to be part of different yarns afterwards. Only after the marking process, the mother yarn is divided into yarns, where each yarn divided from the mother yarn may comprise the same number or pattern of marks.

In an embodiment of the carpet manufacturing method, the step of providing, for a plurality of yarns each having a length, a plurality of marks on each yarn at selected locations along the yarn may comprise: providing an unmarked mother yarn having a length of at least the sum of the lengths of the yarns; dividing the mother yarn into the yarns; and providing a plurality of marks on each yarn at selected locations along the yarn. Also in this case, the marked yarns all are produced from the same mother yarn, and thereby are likely to have substantially the same mechanical and dimensional properties. This may considerably reduce differences between different marked yarns, and may facilitate the yarn uptake control.

In an embodiment, each yarn comprises a pattern of marks, and all yarns have a same pattern of marks. In an embodiment of a pattern, a distance between consecutive marks along the yarn is constant. Distances may be in the order of 10 m, 50 m, 100 m, 200 m, 500 m, or greater. In another embodiment of a pattern, a distance between consecutive marks along the yarn is variable. Although the pattern may be variable on a yarn, the variable pattern may be the same for each yarn processed. A same pattern involves that if the uptake of the yarns would be the same, a detection of marks at some distance from the carpet manufacturing apparatus would result in the simultaneous detection of a mark at all yarns. If the uptake of the yarns is not the same, the uptake control described above can be applied. It is to be noted, however, that for the carpet manufacturing method of the present invention, it is not necessary that all yarns carry the same pattern of marks.

Herein, a pattern of marks on a yarn indicates a number and distribution of marks on a yarn, i.e. for each mark on a yarn, a specific location along the length of the yarn is selected. The yarn may have a plurality of marks along its length, each one located at a specific location along the length of the yarn. Intervals between subsequent marks along the length of the yarn may be regular, or irregular, or increasing, or decreasing, or any other suitable pattern. Intervals between subsequent marks may be long or short, as long as one mark can be distinguished from another mark in the detection thereof.

In an embodiment of a variable pattern, a distance between consecutive marks decreases along the yarn from a leading end thereof to a trailing end thereof. A leading end of a yarn is to be understood as an end which is the first to reach a carpet manufacturing apparatus, whereas a trailing end of a yarn is to be understood as an end which is the last to reach a carpet manufacturing apparatus. Accordingly, the number of marks per unit of length of a yarn increases towards the trailing end of the yarn, allowing for a more accurate correction of uptake errors in a changeover from one carpet product to a next carpet product, thereby ensuring that indeed all yarns for one carpet product are used up at the same time.

In an embodiment, during the step of providing marks on a yarn, the yarn is tensioned at a predetermined tension. At the predetermined tension, the yarn is stretched relative to its untensioned state. At the predetermined tension, distances between marks are determined. Preferably, the predetermined tension corresponds to a tension of the yarn in the step of detecting, for each yarn, the consecutive marks on the yarn upstream of the carpet manufacturing apparatus. Thus, it can be ensured that an intended distance set between marks during the marking of the yarn, is virtually the same when processing the yarn to manufacture the carpet product. In an embodiment, for a yarn, the uptake of the yarn is controlled by: in association with the step of providing the marks on the yarn, storing a first distance between a first mark on the yarn and a second mark on the yarn; at the step of detecting the marks on the yarn, measuring a second distance between the first mark on the yarn and the second mark on the yarn; comparing the first distance with the second distance and, if the first distance is larger than the second distance, decreasing the uptake of the yarn; and, if the first distance is smaller than the second distance, increasing the uptake of the yarn. In theory, in particular when the yarn is tensioned at the same tension during the provision of marks on the yarn and during the processing of the yarn to manufacture a carpet product, the first distance is virtually the same as the second distance. However, practically, these first and second distances may differ due to all kinds of varying conditions for the yarn, thereby necessitating the yarn uptake control of the present invention.

In an embodiment, the second distance is measured by: determining a first yarn length value at a time of detection of the first mark on the yarn; determining a second yarn length value at a time of detection of the second mark on the yarn; and determining the second distance by subtracting the first yarn length value from the second yarn length value. Yarn length value may be measured by the yarn engaging a yarn length measuring device, such as a rotary device engaging the yarn, and providing voltage and/or current and/or data values representative of displacement of the yarn relative to the length measuring device. The first yarn length value may be stored in a memory to be available when the second yarn length value becomes available.

In an embodiment of the carpet manufacturing method, wherein the detecting of marks on a first yarn and a second yarn is at a same distance from the carpet manufacturing apparatus for the first and the second yarn, the uptake of the first yarn is controlled by comparing a first detection time of a first mark on the first yarn with a second detection time of a second mark on the second yarn, and if the first detection time is earlier than the second detection time, decreasing the uptake of the first yarn, or increasing the uptake of the second yarn; and if the first detection time is later than the second detection time, decreasing the uptake of the second yarn, or increasing the uptake of first yarn. In this embodiment, a detection of a mark on the moving yarn at a particular point in time may provide a time stamp in relation to the yarn. For respective yarns, respective time stamps may be obtained. By comparing the time stamps of two respective yarns, it may be determined which one of the two yarns has a higher uptake than the other one. When it is desired that the two yarns have the same uptake, the uptake of the yarn having the leading mark (the earlier time stamp) may be decreased, or the uptake of the yarn having the trailing mark (the later time stamp) may be increased, to reach this goal of equal uptake. Of course, also both measures may be taken in combination. Taking these measures may further be subject to exceeding a predetermined threshold, i.e. a minimum time difference between detection times for respective yarns.

In an embodiment of the carpet manufacturing method, a speed of at least one yarn is measured, and a difference between a first distance between the first mark and the carpet manufacturing apparatus and a second distance between the second mark and the carpet manufacturing apparatus is determined from said yarn speed and a time difference between the first detection time and the second detection time. Here, combining a yarn speed with the time difference, such as to determine the product of the yarn speed and the time difference, will provide a distance between the first mark and the second mark to the carpet

manufacturing apparatus. From this distance, possibly combined with further information on a desired distance, which may be zero, or below a predetermined threshold, or at

predetermined value, it may be decided to adapt the uptake of at least one of the first and the second yarn.

In an embodiment of the carpet manufacturing method, an operating speed of the carpet manufacturing apparatus is measured, and a difference between a first distance between the first mark and the carpet manufacturing apparatus and a second distance between the second mark and the carpet manufacturing apparatus is determined from said carpet manufacturing apparatus operating speed and a time difference between the first detection time and the second detection time. Here, combining an operating speed of the carpet manufacturing apparatus with the time difference, such as to determine a product of the operating speed, the time difference, and possibly a scaling factor, will provide a distance between the first mark and the second mark to the carpet manufacturing apparatus. From this distance, possibly combined with further information on a desired distance, which may be zero, or below a predetermined threshold, or at a predetermined value, it may be decided to adapt the uptake of at least one of the first and the second yarn.

In an embodiment of the carpet manufacturing method, the detecting of a mark on a number of the yarns is at the same distance from the carpet manufacturing apparatus for each yarn, the uptake of a particular yarn is controlled by comparing a particular detection time of a particular mark on the particular yarn with a mean detection time of corresponding marks on the number of yarns, and if the particular detection time is earlier than the mean detection time, decreasing the uptake of the particular yarn, or increasing the uptake of at least one of the other yarns of the number of yarns; and if the particular detection time is later than the mean detection time, decreasing the uptake of at least one of the other yarns of the number of yarns, or increasing the uptake of particular yarn. The particular yarn may or may not be one of the number of yarns. In this embodiment, a detection of a mark on the moving particular yarn at a particular point in time may provide a particular time stamp in relation to the particular yarn. For the number of moving yarns, time detection of marks may result in a plurality of time stamps, of which a mean time, and thus a mean time stamp may be determined. By comparing the particular time stamp and the mean time stamp, it may be determined whether the particular yarn has a higher or lower uptake than a mean uptake of the number of yarns. When it is desired that the particular yarn has the same uptake as the mean uptake of the number of yarns, if the uptake of the particular yarn is indicated by an earlier particular time stamp than the mean time stamp, the uptake of the particular yarn may be decreased to reach a goal of equal uptake. If, on the other hand, the uptake of the particular yarn is indicated by a later particular time stamp than the mean time stamp, the uptake of the particular yarn may be increased, to reach a goal of equal uptake. Of course, also both measures may be taken in combination. Taking these measures may further be subject to exceeding a predetermined threshold, i.e. a minimum time difference between detection times (particular detection time and mean detection time) for the particular yarn and the number of yarns.

In an embodiment of the carpet manufacturing method, a speed of at least one yarn (including the particular yarn, or one of the number of yarns) is measured, and a difference between a distance between the particular mark and the carpet manufacturing apparatus and a mean distance between the corresponding marks and the carpet manufacturing apparatus is determined from said yarn speed and a time difference between the particular detection time and the mean detection time. Here, combining a yarn speed with the time difference, such as to determine the product of the yarn speed and the time difference, will provide a distance between the particular mark and the mean distance between the corresponding marks to the carpet manufacturing apparatus. From this distance, possibly combined with further information on a desired distance, which may be zero, or below a predetermined threshold, or at predetermined value, it may be decided to adapt the uptake of at least one of the particular yarn and the number of yarns.

In an embodiment of the carpet manufacturing method, an operating speed of the carpet manufacturing apparatus is measured, and a difference between a distance between the particular mark and the carpet manufacturing apparatus and a mean distance between the corresponding marks and the carpet manufacturing apparatus is determined from said carpet manufacturing apparatus operating speed and a time difference between the particular detection time and the mean detection time. Here, combining an operating speed of the carpet manufacturing apparatus with the time difference, such as to determine a product of the operating speed, the time difference, and possibly a scaling factor, will provide a distance between the particular mark and the mean distance between the corresponding marks to the carpet manufacturing apparatus. From this distance, possibly combined with further information on a desired distance, which may be zero, or below a predetermined threshold, or at predetermined value, it may be decided to adapt the uptake of at least one of the particular yarn and the number of yarns.

In an embodiment of the carpet manufacturing method, a systematic deviation in the uptake of at least one yarn is determined, and the location of the mark on the yarn is selected in accordance with the systematic deviation, when providing the mark. This will reduce correction of uptake of the yarn.

In some embodiments of the carpet manufacturing method, the uptake of the yarn by the carpet manufacturing apparatus is controlled by adapting a tension in the yarn upstream of the carpet manufacturing apparatus, wherein the uptake of the yarn is decreased by raising a tension in the yarn, and wherein the uptake of the yarn is increased by lowering a tension in the yarn. For different types of yarn, a relationship between yarn uptake and yarn tension can be established, and used for controlling the uptake of the yarn.

In an embodiment of the carpet manufacturing method, the tension in the yarn is adapted by a yarn tension control device arranged upstream of the carpet manufacturing apparatus, wherein the yarn tension control device is configured to frictionally engage the yarn, and to exert a force on the yarn in the longitudinal direction of the yarn. The tension control device may engage the yarn at all times, where the force on the yarn may be zero, driving (i.e., lowering the tension downstream) or braking (i.e., raising the tension

downstream) during a time period, as required. In some embodiments, the tension control device may engage the yarn only during a selected time to produce a desired driving or braking thereof. It is noted that this way of yarn uptake control may be combined with other ways of yarn uptake control.

In an embodiment of the carpet manufacturing method, the carpet manufacturing apparatus comprises a yarn loop forming device cooperating, for each yarn, with an upstream controllable yarn feed roll which in combination provide a controllable yarn feed, and the uptake of the yarn by the carpet manufacturing apparatus is controlled by controlling the yarn feed of the yarn feed roll. Yarn loop forming devices in combination with, for each yarn, an upstream controllable yarn feed roll, are known e.g. from US6283053. US6439141 ,

US6502521 and US6508185, e.g. for providing a desired tufting pattern in a tufted product, where some part of the tufted product has higher piles than another part. The carpet manufacturing method of the present invention proposes to (possibly further) adapt the control of the controllable yarn feed roll to control the uptake of the yarn. The resulting pile height change is minute, and invisible to the human eye in the end product. Such pile height changes can only be established with special measuring devices. In embodiments of the carpet manufacturing method, the uptake of the yarn is decreased by decreasing the yarn feed by the yarn feed roll, and the uptake of the yarn is increased by increasing the yarn feed by the yarn feed roll. It is noted that this way of yarn uptake control may be combined with other ways of yarn uptake control.

In an embodiment of the carpet manufacturing method, prior to storing a length of each yarn, each yarn is provided with its desired marking, providing at least one mark on the yarn. Thus, each yarn, when stored, which may be off-line, is ready to be used in the carpet manufacturing method.

In its simplest form, a mark comprises one marking. This may prove to be sufficient for performing the method of the present invention. In some embodiments, one mark on a yarn needs to be distinguishable from another mark on the same yarn. Therefore, in an

embodiment of the carpet manufacturing method, a mark comprises at least two markings at spaced longitudinal sections of the yarn. Marks can thus be coded to allow a mark to be recognized during detection of the mark as a mark located at a predetermined location. This may increase the reliability of the method. It can thus be prevented that a detection of a mark is mistakenly taken for a detection of another mark. In some embodiments having coded marks, one of the markings of the mark has a length different from another marking of the mark, the mark resembling a barcode known in other technical fields. In some embodiments having coded marks, one of the markings of the mark comprises a marking material different from the marking material of another marking of the mark. The different marking materials can be detected by different detectors, making the detection more reliable, and facilitating error detection.

In an embodiment of the carpet manufacturing method, providing a mark on a yarn comprises applying a marking material on a longitudinal section of the yarn. The mark, consisting of the marking material, extends over some length on the yarn from a leading edge of the section (as seen in a direction of uptake of the yarn) to a trailing edge of the section. As described above, the mark may comprise one or more markings within said longitudinal section of the yarn. Each marking extends on a longitudinal sub-section of the yarn. Thus, said longitudinal section of the yarn may comprise a plurality of sub-sections for a plurality of markings. If the mark comprises a plurality of markings, the mark extends from a leading edge of a first sub-section to a trailing edge of a last sub-section (as seen in a direction of uptake of the yarn).

In an embodiment of the carpet manufacturing method, providing a mark on a yarn comprises spraying a marking material on the yarn. In some embodiments, a nozzle for applying a liquid marking material and/or a powdered marking material may be located at some distance from the surface of the yarn. In some embodiments, the marking material is applied on the yarn from different directions along its circumference. Thus, it can be assured that the mark can be detected from any direction along the circumference of the yarn. In an embodiment of the carpet manufacturing method, after applying the marking material on the yarn, a radiation, such as infrared, IR, radiation and/or ultraviolet, UV, radiation is applied to the marking material. Such radiation may dry or cure the marking material such as to fix it to the yarn to be detectable at a later stage.

In an embodiment, the mark comprises a fluorescent material. Such a mark can be detected by a detector that is sensitive to a radiation emitted by the fluorescent material. The fluorescent effect can be selected such that the fluorescent material is invisible to the human eye when using the carpet product comprising the yarn carrying the mark.

In an embodiment of the carpet manufacturing method, the mark comprises a metal. Such a mark can be detected in the carpet manufacturing method by a metal detector arranged near the yarn.

In an embodiment of the carpet manufacturing method, the mark comprises a magnetizable metal. Such a mark can be detected in the carpet manufacturing method by a magnetic field detector arranged near the yarn.

In an embodiment of the carpet manufacturing method, the mark comprises a material responsive to UV or IR radiation. An UV or IR radiation emitter may be arranged near the yarn, and in response to receiving the UV or IR radiation, the mark may emit radiation which can be detected by an appropriate detector arranged near the yarn.

In an embodiment of the carpet manufacturing method, directly after providing the mark on the yarn, a presence of the mark on the yarn is sensed. Since the method of the present invention relies on the presence of at least one mark on a yarn, it should be secured that indeed a mark is present when it is intended to provide the mark. By checking the presence of the mark, any malfunction of a device for providing the mark can be detected at an early stage of the process, and appropriate action can be taken if such malfunction occurs before it leads to a fault in the carpet manufacturing process for lack of detection of an expected mark on a yarn.

In a further aspect of the present invention, a carpet manufacturing assembly is provided, the carpet manufacturing assembly comprising: a plurality of storages, each configured to store a length of yarn thereon or therein, each yarn comprising a plurality of marks at selected locations along the yarn; a carpet manufacturing apparatus configured to process the yarns to form at least part of a carpet; a feeding device configured to feed each yarn from its associated storage to the carpet manufacturing apparatus; a detecting device configured to: detect, for a yarn, the marks on the yarn upstream of the carpet manufacturing apparatus; and output, for the yarn, a yarn mark detection signal. The carpet manufacturing assembly further comprises a yarn uptake control device configured to: receive the yarn mark detection signals; and control, on the basis of the yarn mark detection signals, the uptake of the yarn by the carpet manufacturing apparatus. An embodiment of the carpet manufacturing assembly further comprises a marking device configured to provide at least one mark on each yarn at a selected location along its length. The marking of yarns may be performed separately from a carpet tufting process in which these yarns are used.

In an embodiment of the carpet manufacturing assembly, the yarn uptake control device is configured to control the uptake of the yarn by: storing, in a memory, a first distance between a first mark on the yarn and a second mark on the yarn determined during marking of the yarn; measuring a second distance between the first mark on the yarn and the second mark on the yarn during detecting the marks of the yarn; comparing the first distance with the second distance, and if the first distance is larger than the second distance, decreasing the uptake of the yarn; and if the first distance is smaller than the second distance, increasing the uptake of the yarn.

In an embodiment of the carpet manufacturing assembly, the yarn mark detection signal comprises a detection time of detecting a mark, and the yarn uptake control device is configured to compare a first detection time of a first mark on a first yarn with a second detection time of a second mark on a second yarn, and, if the first detection time is earlier than the second detection time, to decrease the uptake of the first yarn, or to increase the uptake of the second yarn; and if the first detection time is later than the second detection time, to decrease the uptake of the second yarn, or to increase the uptake of first yarn.

In an embodiment of the carpet manufacturing assembly, the yarn mark detection signal comprises a detection time of detecting a mark, and the uptake control device is configured to compare a particular detection time of a mark on a particular yarn with a mean detection time of corresponding marks on a number of yarns, and, if the particular detection time is earlier than the mean detection time, to decrease the uptake of the particular yarn, or to increase the uptake of at least one of the other yarns of the number of yarns; and if the particular detection time is later than the mean detection time, to decrease the uptake of at least one of the other yarns of the number of yarns, or to increase the uptake of the particular yarn.

In some embodiments, the carpet manufacturing assembly further comprises a yarn tension control device configured to adapt a yarn tension based on a yarn uptake control signal from the yarn uptake control device. In some embodiments, the yarn tension control device is arranged upstream of the carpet manufacturing apparatus, wherein the yarn tension control device is configured to frictionally engage the yarn, and to exert a force on the yarn in the longitudinal direction of the yarn.

In an embodiment of the carpet manufacturing assembly, the carpet manufacturing apparatus comprises a tufting apparatus including a yarn loop forming device cooperating, for each yarn, with an upstream controllable yarn feed roll which in combination provide a controllable yarn feed, and the uptake of the yarn by the carpet manufacturing apparatus is controlled by controlling the yarn feed of the yarn feed roll based on a yarn uptake control signal from the yarn uptake control device.

In an embodiment of the carpet manufacturing assembly, the marking device comprises at least one nozzle configured to provide a marking material on a yarn.

In a still further aspect, the present invention provides a yarn marking device for use in the carpet manufacturing method of the present invention and/or for use in the carpet manufacturing assembly of the present invention.

In a still further aspect, the present invention provides a computer program enabling a processor to carry out the controlling step of the carpet manufacturing method.

In a still further aspect, the present invention provides a computer program enabling the yarn uptake control device of the carpet manufacturing assembly to receive the yarn mark detection signals, and to control, on the basis of the yarn mark detection signals, the uptake of the yarn by the carpet manufacturing apparatus.

These and other aspects of the invention will be more readily appreciated as the same becomes better understood by reference to the following detailed description and considered in connection with the accompanying drawings in which like reference symbols designate like parts.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 depicts a schematic view of a section of a yarn marking device and a mark detecting device according to the present invention.

Figures 2a, 2b, 2c and 2d illustrate a part of a yarn comprising marks, with some marks comprising markings, wherein Figure 2d is shown on an enlarged scale.

Figure 3 depicts a diagram of a carpet manufacturing assembly according to the present invention.

Figures 3a, 3b and 3c depict flow diagrams illustrating different control yarn uptake control methods according to the present invention.

Figure 4 illustrates a yarn tension control device according to the present invention.

DETAILED DESCRIPTION OF EMBODIMENTS

Figure 1 depicts a longitudinal section of a yarn marking device 100. The marking device 100 comprises a duct 102 extending in a longitudinal direction thereof from a first opening 104 to a second opening 106. The duct 102 may be straight. The first opening 104 is located at a yarn supply side of the marking device 100, and the second opening 106 is located at a yarn discharge side of the marking device 100, with a yarn 108 having a direction of conveyance through the duct 102 in the direction of arrow 110. For clarity, the yarn 108 is shown with a thickness which may be exaggerated when compared to an actual thickness of some yarns.

The marking device 100 may comprise one duct 102 per yarn 108, may comprise a duct 102 for a plurality of yarns 108, or may comprise a plurality of ducts 102 each for a plurality of respective yarns 108.

The conveyance of the yarn 108 in the duct 102 may be continuous or intermittent. In case of a continuous conveyance, the speed of the yarn 108 moving through the duct 102 may be fixed or variable.

In the duct 102, which may have a circular cross-section or a polygonal cross-section, such as a square or a hexagonal cross-section, one or more nozzles 112 are provided. Each nozzle 1 12 may spray or jet (herein commonly: spray) a marking material 114 from a reservoir or holder 1 16 through an actuator 118 onto the yarn 108 at a location opposite the nozzle 112 or a mouthpiece thereof. The holder 116 and actuator 1 18 are only shown for one nozzle 1 12 in Figure 1. When a plurality of nozzles 1 12 is used, each nozzle 1 12 may spray a marking material 114 onto the yarn 108 from a different angle, such as different angles in a plane at right angles to a longitudinal direction of the yarn 108. If a plurality of nozzles 112 is arranged around the circumference of the duct 102, a marking material 1 14 may be sprayed on the yarn 108 from different directions around the yarn 108, thus creating a substantially ring-shaped mark on the yarn 108. It is noted here, that in view of the usually relatively small diameter of a yarn 108, one, or two opposite nozzles 1 12 may be sufficient to provide a mark that may be detected from any radial direction around the mark.

A length of the mark created by the one or more nozzles 1 12 on the yarn 108 depends on a speed of movement of the yarn in the direction of the arrow 1 10 in combination with the length of time of spraying or jetting, assuming that the marking device 100 itself is stationary.

The marking device 100 may comprise one or more further nozzles in the longitudinal direction of the duct 102, as exemplified in Figure 1 by nozzles 1 12a. Nozzles 112 and 1 12a may be made to spray simultaneously, actuated by one or more actuators 1 18. The nozzles 1 12 and 112a may also be made to spray overlapping in time, or distinctly in time, each actuated by a separate corresponding actuator 118. Nozzle(s) 112 may spray the same or a different marking material than nozzle(s) 1 12a.

A marking material is sprayable through a nozzle 1 12, 1 12a, and is in liquid or powder form upstream of an opening of a nozzle 112, 112a. After leaving the nozzle 1 12, 112a, the marking material reaches a part of a yarn 108 opposite (at that moment in time) the nozzle 1 12, 112a. On the yarn 108, the marking material is to attach to the yarn material at least temporarily. In some embodiments, the marking material dries by natural or forced evaporation of solvents contained therein. In some embodiments, the marking material is dried by applying heat or other radiation, such as radio frequency, RF, radiation thereto from a suitable radiation source 120. In some embodiments, the marking material may be cured by applying infrared, IR, radiation or ultraviolet, UV radiation from a suitable radiation source 120.

In some embodiments, the marking material may be invisible to the human eye. The effect is that the marking material, although present, will not show in the carpet product comprising the yarn 108 with the marking material provided on it. In some embodiments, the marking material, once irradiated with light having a suitable wavelength (either visible or invisible to the human eye), may emit light having a wavelength in a range which is detectable by a mark detector.

In some embodiments, the marking material comprises a metal, or a magnetizable material. Such marking material may be detected by a metal detector, or a magnetic field detector, respectively.

In an embodiment, the yarn 108 may have been produced and colored such as to have different longitudinal sections having different colors, where such different sections are intended to create a specific aesthetic or technical effect in the carpet product to be produced. In such circumstances, specific sections having a specific color, and alternating with other sections having another color, may be used to function as a marker, and no specific mark or marks need to be provided in a marking device. In an embodiment, the specific sections have a length which is substantially smaller than the length of adjacent other sections.

Downstream (as seen in the direction of movement of the yarn 108) of the marking device 100, at least one mark detecting device 130 may be provided to detect a mark on the yarn 108. The mark detecting device 130 may be separate from the marking device 100, but also may form one unit with the marking device 100. The mark detecting device 130 is provided to check the proper functioning of the marking device 100, by one or more detectors 132, 132a detecting whether or not a mark is provided on the yarn 108 when just previously a marking material was (intended to be) sprayed form the nozzle(s) 112, 112a. If a mark is not detected while a command was given to spray the mark on the yarn 108, a malfunction of the marking device may be concluded, and proper measures may be taken for repair.

Figures 2a, 2b and 2c illustrate a yarn comprising marks.

Referring to Figure 2a, a yarn 108 may be provided with marks 202, 204, 206, 208, 210. Measured along the yarn 108, a distance between mark 202 and mark 204 is L1 , a distance between mark 204 and mark 206 is L2, a distance between mark 206 and mark 208 is L3, and a distance between mark 208 and mark 210 is L4. A length of any of the marks 202-210, measured along the yarn 108, is substantially smaller than any of the distances L1- L4. Distances L1 , L2, L3 and L4 may differ from each other. In the embodiment of Figure 2a, distances L1 and L2 are larger than distances L3 and L4.

Referring to Figure 2b, marks 212, 214 and 216 are provided. Distances between the marks 212, 214 and 216 may be different or may be the same. The marks 212 and 216 each comprise two markings 212a, 212b and 216a, 216b, respectively, whereas the mark 214 comprises one marking 215. When detecting the marks 212, 214 and 216, in particular in a sequence, the mark 216 can be clearly distinguished from the mark 214, and the mark 214 can be clearly distinguished from the mark 212, on the basis of number of the markings (two, one and two, respectively).

Referring to Figure 2c, marks 220, 222 and 224 are provided. Distances between the marks 220, 222 and 224 may be different or may be the same. The mark 220 comprises two markings 220a, 220b of equal length along the longitudinal direction of the yarn 108. The mark 222 comprises two markings 222a, 222b of different length along the longitudinal direction of the yarn 108, wherein the marking 222a is shorter than the marking 222b. The mark 224 comprises two markings 224a, 224b of different length along the longitudinal direction of the yarn 108, wherein the marking 224a is longer than the marking 224b. When detecting the marks 220, 222 and 224, the mark 224 can be clearly distinguished from the mark 222 and the mark 220, on the basis of the unique combination of lengths of the markings 224a, 224b. Similarly, the mark 222 can be clearly distinguished from the mark 220 and the mark 224, on the basis of the unique combination of lengths of the markings 222a, 222b. Also, the mark 220 can be clearly distinguished from the mark 222 and the mark 224, on the basis of the unique combination of lengths of the markings 220a, 220b. Each of the marks 220, 222 and 224 is coded according to a combination of marking lengths, which may be unique for each mark.

Figure 2d shows a part of a yarn 108 having a mark 230 comprising two markings

230a, 230b thereon. The mark 230 involves a longitudinal section S1 of the yarn 108. The markings 230a, 230b have longitudinal sections S2 and S3, respectively, wherein S2+S3<S1.

Figure 3 depicts an embodiment of a carpet manufacturing assembly 300 processing a plurality of yarns to produce a carpet product, such as a tufted carpet product. The carpet manufacturing assembly comprises a plurality of storages 302, each of which is configured to store a length of yarn thereon or therein. A storage may e.g. comprise a bobbin with a length of yarn wound on it, or a tube with a length of yarn stored in it. Each yarn has been provided with marks using a marking device such as illustrated in Figure 1.

From the storages 302, yarns are fed through a feeding device 304 to a carpet manufacturing apparatus 306. The feeding device 304 is configured to feed each yarn from its associated storage 302 to the carpet manufacturing apparatus 306. The carpet manufacturing apparatus may be a tufting apparatus configured to process the yarns to form at least part of a carpet. The feeding device 304 may comprise a system of tubes, each tube guiding a yarn from its storage 302 to the carpet manufacturing apparatus 306.

Upstream of the carpet manufacturing apparatus 306, a detecting device 308 is arranged. The detecting device 308 is configured to detect, for each yarn, the marks on the yarn upstream of the carpet manufacturing apparatus 306 and output, for each yarn, a yarn mark detection signal 310. A yarn uptake control device 312 is configured to receive the yarn mark detection signals 310 and to control, on the basis of the yarn mark detection signals 310, the uptake of the yarns 108 by the carpet manufacturing apparatus 306.

In an embodiment, the yarn uptake control device 312 comprises a controller, processor or computer system, configured to execute computer program instructions to perform the control function(s) of the yarn uptake control device 312. A computer code associated with the computer program instructions may be stored in a memory of the yarn uptake control device 312, or at another location in the carpet manufacturing assembly 300, or at a remote location.

In some embodiments, the yarn mark detection signal 310 comprises a detection time of detecting a mark.

In some embodiments, the yarn uptake control device 312 is configured to control the uptake of the yarn by storing, in a memory 31 1 , a first distance between a first mark on the yarn 108 and a second mark on the yarn 108 determined during marking of the yarn 108, measuring a second distance between the first mark on the yarn 108 and the second mark on the yarn 108 during detecting the marks of the yarn, comparing the first distance with the second distance, and, if the first distance is larger than the second distance, decreasing the uptake of the yarn 108, while, if the first distance is smaller than the second distance, increasing the uptake of the yarn 108.

This control method is illustrated in the flow diagram of Figure 3a. Marks are provided on a yarn 108 (step 320). While marking the yarn 108, or after marking the yarn 108, each distance between subsequent marks 108 is stored in a memory 311 (step 322). For two subsequent marks 108, a first mark and a second mark, this results in one first distance between the first mark and the second mark on the yarn. For more than two subsequent marks 108, this results in a plurality of first distances between each pair of subsequent marks. When manufacturing a carpet, the marks 108 are detected on the yarn 108 (step 324). Each distance between subsequent marks 108 is measured (step 326). Thus, for each pair of subsequent marks 108, a second distance is measured. Then, the first distance is compared with the second distance (step 327), where the first distance concerns a distance between two subsequent marks, and the second distance concerns a distance between the same two subsequent marks. First, it may be determined whether the first distance is greater than the second distance (step 328). If this is the case (arrow Y), then the uptake of the yarn 108 is decreased (step 332). If this is not the case (arrow N), then it is determined whether the first distance is smaller than the second distance (step 330). If this is the case (arrow Y), then the uptake of the yarn 108 is increased (step 334). If this is not the case (arrow N), then it is concluded that the first distance is equal to the second distance, implying that the uptake of the yarn is correct and need not be changed. It is noted here that each measurement of a distance involves some inherent inaccuracy, which may be taken into account when comparing the first distance with the second distance. Then, a new mark 108 may be detected (step 324) to thereby measure a new second distance between two subsequent marks, one of which was detected before, and one of which is the new mark 108. For the same pair of marks, the corresponding first distance has been stored before (step 322), so that again the first distance and the second distance may be compared to thereby determine whether or not to change the uptake of the yarn 108. This process continues until the whole yarn 108 has been processed.

In some embodiments, the yarn uptake control device 312 is configured to compare a first detection time of a first mark on a first yarn 108 with a second detection time of a second mark on a second yarn 108, and, if the first detection time is earlier than the second detection time, to decrease the uptake of the first yarn 108, and/or to increase the uptake of the second yarn 108, and, if the first detection time is later than the second detection time, to decrease the uptake of the second yarn 108, and/or to increase the uptake of first yarn 108.

This control method is illustrated in the flow diagram of Figure 3b. When manufacturing a carpet, on a first yarn 108 a first mark is detected at a first detection time (step 340). On a second yarn 108 a second mark is detected at a second detection time (step 342). Then, the first detection time is compared with the second detection time (step 343). First, it may be determined whether the first detection time is at an earlier point in time than the second detection time (step 344). If this is the case (arrow Y), then the uptake of the first yarn 108 is decreased, and/or the uptake of the second yarn 108 is increased (step 348). If this is not the case (arrow N), then it is determined whether the first detection time is at a later point in time than the second detection time (step 346). If this is the case (arrow Y), then the uptake of the first yarn 108 is increased, and/or the uptake of the second yarn 108 is decreased (step 350). If this is not the case (arrow N), then it is concluded that the first detection time is equal to the second detection time, implying that the uptake of the first yarn in relation to the uptake of the second yarn is correct and need not be changed. It is noted here that each measurement of a detection time involves some inherent inaccuracy, which may be taken into account when comparing the first detection time with the second detection time. Then, new first and second marks may be detected on the first and second yarns 108, respectively (steps 340, 342) to thereby detect new first and second detection times, so that again the first detection time and the second detection time may be compared to thereby determine whether or not to change the uptake of the first yarn and/or the second yarn 108. This process continues until the whole first and second yarns 108 have been processed.

In some embodiments, the yarn uptake control device 312 is configured to compare a particular detection time of a mark on a particular yarn 108 with a mean detection time of corresponding marks on a number of yarns 108, and, if the particular detection time is earlier than the mean detection time, to decrease the uptake of the particular yarn 108, and/or to increase the uptake of at least one of the other yarns 108 of the number of yarns 108, and, if the particular detection time is later than the mean detection time, to decrease the uptake of at least one of the other yarns 108 of the number of yarns 108, and/or to increasing the uptake of particular yarn 108.

This control method is illustrated in the flow diagram of Figure 3c. When

manufacturing a carpet, a detection time of each one of a number of corresponding marks on a number of yarns 108 (one mark and one detection time per yarn) is detected (step 360). From the number of detection times for the corresponding marks on the number of yarns108, a mean detection time is determined (step 362). Then, one of the detection times (a particular detection time for a particular mark on a particular yarn) is compared with the mean detection time (step 364). First, it may be determined whether the particular detection time is at an earlier point in time than the mean detection time (step 366). If this is the case (arrow Y), then the uptake of at least one of the other yarns (other than the particular yarn) 108 is increased, and/or the uptake of the particular yarn is decreased (step 368). If this is not the case (arrow N), then it is determined whether the particular detection time is at a later point in time than the mean detection time (step 370). If this is the case (arrow Y), then the uptake of at least one of the other yarns (other than the particular yarn) 108 is decreased, and/or the uptake of the particular yarn is increased (step 372). If this is not the case (arrow N), then it is concluded that the particular detection time is equal to the mean detection time, implying that the uptake of the particular yarn may be deemed to be correct and need not be changed. The same comparison of a particular detection time with a mean detection time may be done for at least one other mark of the number of corresponding marks, or for each one of the number of corresponding marks. It is noted here that each measurement of a detection time involves some inherent inaccuracy, which may be taken into account when comparing the particular detection time with the mean detection time. Then, for each one of a next number of corresponding marks on a number of yarns 108, a detection time may be detected (step 360), so that again one or more particular detection time may be compared to a mean detection time to thereby determine whether or not to change the uptake of the one or more particular yarns 108 or any of the other yarns. This process continues until the whole yarn 108 has been processed. The yarn uptake control device 312 may produce a yarn uptake control signal 314 for each yarn. The yarn uptake control signal 314 is used to control the uptake of the yarn.

As illustrated with a dashed arrow, in some embodiments, the yarn uptake control signal 314 is fed to a yarn tension control device 316 arranged downstream of the detecting device 308 and upstream of the carpet manufacturing apparatus 306. The yarn tension control device 316 is configured to adapt a yarn tension of each yarn based on the yarn uptake control signal 314 from the yarn uptake control device 312.

As illustrated with a dashed arrow, in some embodiments, in which the carpet manufacturing apparatus 306 comprises a tufting apparatus known per se including a yarn loop forming device cooperating, for each yarn, with an upstream controllable yarn feed roll which in combination provide a controllable yarn feed, and the uptake of the yarn by the carpet manufacturing apparatus is controlled by controlling the yarn feed of the yarn feed roll based on the yarn uptake control signal 314 from the yarn uptake control device 312.

Figure 4 illustrates and embodiment of a yarn tension control device 316. The yarn tension control device 316 comprises a wheel 402 having a circumferential groove 404 which may have a V-shaped or U-shaped cross-section to guide a yarn 108 therein, moving in the direction of arrow 1 10. The wheel 402 is coupled to a drive device 406, and frictionally engages the yarn 108, and thereby may exert a force on the yarn 108 in the longitudinal direction of the yarn 108 during rotation of the wheel 402 around an axis 408 in a direction indicated by arrow 410. The drive device 406 may either drive the wheel 402 to drive the yarn 108, thereby exerting a force on the yarn 108 in the direction of arrow 110, or brake the wheel 402 to brake the yarn 108, thereby exerting a force on the yarn 108 opposite to the direction of the arrow 1 10, or not exert a force on the yarn 108 (idling) in the direction of arrow 1 10. A particular action of driving, braking or idling is determined by the yarn uptake control signal 314 fed to the drive device 406. In the case of the wheel 402 driving the yarn 108, a tension in the yarn 108 downstream of the area of contact between the wheel 402 and the yarn 108 decreases. In the case of the wheel 402 braking the yarn 108, a tension in the yarn 108 downstream of the area of contact between the wheel 402 and the yarn 108 increases. With a decrease of the tension in the yarn 108 downstream of the yarn tension control device 316, an uptake of the yarn 108 in the carpet manufacturing apparatus 306 downstream of the yarn tension control device 316 increases. With an increase of the tension in the yarn 108 downstream of the yarn tension control device 316, an uptake of the yarn 108 in the carpet manufacturing apparatus 306 downstream of the yarn tension control device 316 decreases.

In relation to Figure 4, it is noted that a construction comprising a wheel 402 and a drive device 406, where the drive device is controllable to exert a driving force on a yarn 108, is suitable to function as a controllable yarn feed roll as described above for a tufting apparatus. It is noted that during performing the operation according to the carpet manufacturing method of the invention, and/or during operation of the carpet manufacturing assembly of the invention, data are generated when marking yarns, when detecting marks and markings on yarns, and when performing controlling functions. Such data may be stored in a database for statistical analysis, and for improving the controlling functions. The database could classify carpet products according to different attributes, like patterns, yarn types, yarn storage types, winding machines used for storing yarns, etcetera. Data in the database could be used to provide a correct yarn uptake control for a yarn deviating from an average yarn. The database could contain expected first distances as defined above between consecutive marks for e.g. multiple yarn markings, multiple work orders, different yarn types and different patterns.

It is further noted that the principle of the present invention can also be used for tufting a (color) pattern in a carpet product by using different (colors of) yarns which may be kept very accurately in register thanks to the marks on the yarns, whereby the right (colors of) yarns arrive at the right location in the carpet product.

As explained above, in a carpet manufacturing method, for a plurality of yarns each having a length, a plurality of marks are provided on each yarn at selected locations along the yarn. In the carpet manufacturing method and in a carpet manufacturing assembly, each yarn is stored on or in an associated storage, and fed from its associated storage to a carpet manufacturing apparatus. For each yarn, the marks on the yarn are detected upstream of the carpet manufacturing apparatus. On the basis of the detection of the marks, the uptake of the yarn by the carpet manufacturing apparatus is controlled, whereafter, in the carpet manufacturing apparatus, the yarns are processed to form at least part of a carpet.

As required, detailed embodiments of the present invention are disclosed herein; however, it is to be understood that the disclosed embodiments are merely exemplary of the invention, which can be embodied in various forms. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a basis for the claims and as a representative basis for teaching one skilled in the art to variously employ the present invention in virtually any appropriately detailed structure. Further, the terms and phrases used herein are not intended to be limiting, but rather, to provide an understandable description of the invention.

The terms "a" or "an", as used herein, are defined as one or more than one. The term plurality, as used herein, is defined as two or more than two. The term another, as used herein, is defined as at least a second or more. The terms including and/or having, as used herein, are defined as comprising (i.e., open language, not excluding other elements or steps). Any reference signs in the claims should not be construed as limiting the scope of the claims or the invention. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage.

The term coupled, as used herein, is defined as connected, although not necessarily directly, and not necessarily mechanically.

A single controller, processor or other processing unit may fulfil the functions of several items recited in the claims.

The term computer program as used herein, are defined as a sequence of instructions designed for execution in a controller, in a processor, or on a computer system. A program, computer program, or software application may include a subroutine, a function, a procedure, an object method, an object implementation, an executable application, an applet, a servlet, a source code, an object code, a shared library/dynamic load library and/or other sequence of instructions designed for execution on a computer system.

A computer program may be stored and/or distributed on a suitable medium, such as an optical storage medium or a solid-state medium supplied together with or as part of other hardware, but also be distributed in other forms, such as via the Internet or other wired or wireless telecommunication systems.