EP1783253B1

EP1783253B1 - Fiber bundle concentrating device in spinning machine and method for manufacturing perforated belt

Info

Publication number: EP1783253B1
Application number: EP06123395A
Authority: EP
Inventors: Naoki Maruyama; Takahisa Ishii; Yoshimasa Fujii
Original assignee: Toyota Industries Corp
Current assignee: Toyota Industries Corp
Priority date: 2005-11-07
Filing date: 2006-11-02
Publication date: 2012-04-11
Anticipated expiration: 2026-11-02
Also published as: KR20070049053A; EP1783253A3; CN1962979B; CN1962979A; KR100733754B1; EP1783253A2; JP2007126798A; JP4774930B2

Description

BACKGROUND OF THE INVENTION

The present invention relates to a fiber bundle concentrating device in a spinning machine, and in particular, to a fiber bundle concentrating device located downstream of a draft machine (draft part) in a fine spinning machine, which bundle concentrating device concentrates fiber bundle that has been drafted by the draft machine.
Various fiber bundle concentrating devices have been proposed for concentrating a drafted fiber bundle in advance, before twisting, for the purpose of enhancing the quality of yarn in such a manner as to reduce fluff. In addition, an endless perforated belt is used for, as a basic function, concentrating and transporting fiber bundles. A belt perforated with many horizontal holes is formed of a textile using a polyamide multifilament yarn.
In addition, for a conveyor belt (a perforated belt) used in a fiber bundle concentrating device, proposals have been made to use an unwoven sheet (for example, see Patent Document 1). In this unwoven sheet, as shown in Fig. 6, warp yarns 51 and weft yarns 52 made of thermoplastic filaments are made so as to cross and overlap, and after that, by means of a heating and melting process, both types of yarns are melted and fixed to each other at intersecting portions. A region in grid form 53 is thereby formed of warp yarns 51 and weft yarns 52.
Patent Document 1: Japanese Laid-Open Patent Publication No. 2004-346472 (paragraphs [0021] to[0023], Figs. 1 and 3)
However, in a case of an endless perforated belt formed of a textile, if ends of yarns are cut or frayed, the cut or frayed yarn ends become entangled with fiber bundles during spinning. This adversely affects the bundles of fibers, causing the breaking of yarns, or defects in the quality of yarn. In addition, once entangling begins, there is also a risk that a perforated belt may quickly deteriorate to a state in which it becomes unusable.
In the conveyor belt of Patent Document 1, warp yarns 51 and weft yarns 52 are made to overlap and a heating process is carried out, and thereby, warp yarns 51 and weft yarns 52 are fused and fixed to each other at all intersecting portions. Accordingly, even in cases where warp yarns 51 or weft yarns 52 that form the conveyor belt (perforated belt) breaks, the ends of broken yarns are prevented from becoming entangled with the spun fiber bundles that that have been delivered. In addition, even if the yarns are frayed, the level of fraying is prevented from deteriorating.
However, in a configuration in which warp yarns 51 and weft yarns 52 which form the conveyor belt are fused and fixed to each other at all intersecting portions, as in the conveyor belt of Patent Document 1, the pliancy of the conveyor belt deteriorates. Consequently, it becomes difficult for the conveyor belt to move smoothly in a state where the conveyor belt follows the outer shape of the guide portion of the fiber bundle concentrating device.

SUMMARY OF THE INVENTION

It is an objective of the present invention to provide a fiber bundle concentrating device in a spinning machine that, without diminishing the ability of the device to bundle and transport the fiber bundle, improves spinning and delivery performance by preventing spun fibers that have been delivered from being pinched, or becoming attached to intersecting portions of the yarns that form a perforated belt, and improves the durability of the perforated belt.
In accordance with one aspect of the present invention, a fiber bundle concentrating device in a spinning machine is provided. The device concentrates fiber bundles drafted by a draft part. The device includes a fiber bundle delivery portion, a suction portion, and a perforated belt. The fiber bundle delivery portion includes a nip roller, and is located downstream of a final delivery roller pair of the draft part. The suction portion has a guide surface. The guide surface has a suction hole at least in a section upstream of a nip point of the delivery portion in a moving direction of the fiber bundles. The perforated belt rotates while sliding on the guide surface. The perforated belt is formed as a sheet body that contains intersecting sets of yarns. Part of intersecting portions of the yarns are fused such that fused regions, where the fused intersecting portions are adjacent to each other, and non-fused regions, where the non-fused intersecting portions are adjacent to each other, are alternately arranged at least in a circumferential direction of the perforated belt.
In accordance with a second aspect of the present invention, a method for manufacturing a perforated belt is provided. The method includes: forming a cylindrical sheet body with intersecting sets of yarns, wherein the yarns in at least one of the sets are thermally fusing yarns; and engaging the sheet body with a cylindrical body having a closed end from the outside, the cylindrical body having a plurality of holes in a circumferential surface, and supplying into the cylindrical body a gas of a temperature that is equal to or higher than the melting point of the thermally fusing yarns, thereby fusing the intersecting yarns to each other at positions of the sheet body that correspond to the holes by the heat of the gas blown out of the holes.
Other aspects and advantages of the invention will become apparent from the following description, taken in conjunction with the accompanying drawings, illustrating by way of example the principles of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention, together with objects and advantages thereof, may best be understood by reference to the following description of the presently preferred embodiments together with the accompanying drawings in which:

Fig. 1A is a schematic side diagram showing a fiber bundle concentrating device and a partial cross section thereof according to one embodiment;
Fig. 1B is a schematic perspective diagram showing a perforated belt on which a fusing process has been carried out;
Fig. 1C is a schematic perspective diagram showing a perforated belt on which no fusing process has been carried out;
Fig. 1D is a schematic diagram showing intersecting portions of yarns in a perforated belt;
Fig. 1E is a schematic diagram for illustrating an aperture ratio;
Fig. 2 is a schematic diagram showing the relationship between portions of a suction portion and a bottom nip roller;
Fig. 3 is a schematic perspective diagram for illustrating a method of fusing yarns in the perforated belt;
Figs. 4A and 4B are schematic diagrams illustrating portions of a configuration of perforated belts according to other embodiments;
Fig. 5 is a schematic side diagram illustrating a fiber bundle concentrating device according to another embodiment; and
Fig. 6 is a schematic perspective diagram illustrating a portion of a conveyor belt according to the prior art.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

In the following is described, with reference to Figs 1A to 3, one embodiment where the present invention is embodied in a fiber bundle concentrating device installed in a fine spinning machine.
The fiber bundle concentrating device has basically the same configuration as the fiber bundle concentrating device in the application by the present applicant ( Japanese Laid-Open Patent Publication 2003-113450 ). As shown in Fig. 1A, a fiber bundle concentrating device 11 is provided on the downstream side of the final delivery roller pairs 13 in a draft machine 12 which serves as a draft part. Each final delivery roller pair 13 is formed of a front bottom roller 14 and a front top roller 15.
The fiber bundle concentrating device 11 is provided with nip roller pairs 16 which serves as a fiber bundle delivery portion, suction portions 17, and perforated belts 18. Each nip roller pair 16 is formed of a bottom nip roller 19a which serves as a driving roller portion that is formed around a rotary shaft 19 provided parallel to the front bottom roller 14, and a top nip roller 20 which is pressed against the bottom nip roller 19a with the corresponding perforated belt 18 in between. Each top nip roller 20 is supported by a weighting arm (not shown) with a support member 21 provided in between for every two spindles, in the same way as the front top roller 15 in the draft machine 12. Each support member 21 is formed so as to be integrated with the corresponding support member for the front top roller 15.
In contrast, in the bottom portion of the fiber bundle concentrating device 11, components corresponding to half of the spindles between roller stands 22 in the draft machine 12, that is to say, four spindles in this embodiment, form one unit. A support arm 23 is placed at central points between each adjacent pair of the roller stands 22 which are positioned at predetermined intervals in a longitudinal direction of the fine spinning machine. The proximal end of each support arm is supported by a support beam (not shown) provided so as to extend in a longitudinal direction of the fine spinning machine at the rear of the back bottom roller (not shown). Each rotary shaft 19 is supported between the corresponding roller stands 22 and support arms 23.
Each rotary shaft 19 is formed so as to have a predetermined length corresponding to a certain number of spindles (four spindles in this embodiment). Bearings (not shown) which are fixed to the two ends of each shaft 19 are engaged with end plugs 25. The end plugs 25 are supported by support portions 22a and 23a which are provided in engagement parts 25a on the roller stands 22 and the support arms 23. The rotary shaft 19 is thereby supported in such a manner as to be rotatable between the roller stands 22 and the support arms 23. Each of the support portions 22a and 23a is formed in such a manner as to be able to support two of the end plugs 25, and is thus capable of supporting the end plugs 25 which are attached to end portions of an adjacent pair of the rotary shafts 19.
A gear 26 is provided at the center of each rotary shaft 19 in a longitudinal direction as a rotational force transmitting portion for transmitting a rotational force from a driving source. The gear 26 is integrally formed with the rotary shaft 19. In this embodiment, the front bottom rollers 14 are used as the driving source of the rotary shafts 19, and a gear portion 14a (shown in Fig. 1A) is formed on each front bottom roller 14 in a position such as to face the corresponding gear 26. In addition, in the same manner as with the support arms 23, an intermediate gear 28 is supported by a support arm 27 which is fixed to the support beam on the proximal end so as to be rotatable, and the intermediate gear 28 engages with the gear portion 14a and the gear 26. In other words, the rotational force of each front bottom roller 14 is transmitted to the corresponding rotary shaft 19 by way of the corresponding set of the gear portion 14a, the intermediate gear 28, and the gear 26.
A suction duct (not shown) is provided on the fine spinning machine so as to extend in a longitudinal direction of the fine spinning machine (in a direction perpendicular to the paper in the case of Fig. 1A). The suction portion 17 is provided with suction pipes 29 and 30 which extend parallel to the rotary shafts 19, and a connecting tube 31 which is linked to the suction duct so as to apply negative pressure onto the suction pipes 29 and 30. The connecting tube 31 is positioned at the front side of the gears 26 so that a portion serves as a cover for the gears 26 and the intermediate gears 28, and is connected to the suction duct at the proximal end by means of a linking tube 32 that assumes a pleated form. The first end portions of suction pipes 29 and 30 are engaged with engagement holes which are created on both sides, left and right, of an end portion of the connecting tube 31, and the second end portions are engaged with end plugs 25.
As shown in Figs. 1A and 2, the suction pipe 29 has a guide surface 29b where suction holes 29a are created so as to extend toward the upstream side of the nipping point between the rollers in the nip roller pairs 16, in a direction in which fiber bundles (fleece) F move. The suction pipe 30 has a guide surface 30b where suction holes 30a are created so as to extend toward the downstream side. In addition, the suction pipe 29 is provided so as to be located on the upstream side of the nipping point of the bottom nip rollers 19a, in a direction in which a fiber bundle F moves, and the suction pipe 30 is provided so as to be located on the downstream side.
As shown in Fig. 1A, provided in the vicinity of the bottom of the suction pipe 30 are ends of suction nozzles 33 of a single type pneumatic apparatus which serves to suck fiber bundles F that are delivered from the draft machine 12 at a time that yarn breaks. The proximal ends of the suction nozzles 33 are connected to the suction duct (not shown).
As shown in Fig. 1A, each perforated belt 18 is engaged with the suction pipes 29 and 30 and the corresponding bottom nip roller 19a so that one portion of the belt 18 makes contact with the suction pipes 29 and 30 and another portion makes contact with the bottom nip roller 19a. Thus, the perforated belt 18 rolls while sliding along the guide surfaces 29b and 30b in accordance with the rotation of the bottom nip roller 19a.
Each perforated belt 18 is formed of a textile of plain weave in a seamless loop form. In this embodiment, each perforated belt 18 is formed by cutting a textile woven in a cylindrical form to a predetermined width after a fusing process has been carried out. As illustrated in Fig. 1D, thermally fusing yarns 34 having a core-sheath structure is used as the yarns that form the textile. Further, in the thermally fusing yarns 34, sheath portions 34a are fused together at intersecting portions 35 of the yarns that form the textile. In this embodiment, in the thermally fusing yarns 34, the core portions 34b and the sheath portion 34a are respectively made of polyamide, and polyamide with a melting point of 260°C and polyamide with a melting point of 220°C are respectively used for the core portion 34b and the sheath portion 34a. Moreover, in this embodiment, the core portion 34b is formed of a monofilament.
The textile is woven with thermally fusing yarns 34 having a diameter (thickness) of from 0.05 mm to 0.15 mm. When the yarns are thin, though suction preferably works on a spun fiber bundle F at a time of delivery, the strength of the perforated belts 18 becomes insufficient, and therefore, a thickness is preferably within the range described above. Further, the textile is formed so as to have an aperture ratio of between 25% and 40%. In this context, the aperture ratio is defined as (A2/A1) x 100(%), in which, as illustrated in Fig. 1E, the area of the portion that is surrounded by the center lines (annotated by broken lines) of two adjacent warp yarns 36a and two adjacent weft yarns 36b is A1, and the area of the aperture (hatched portion) surrounded by the two warp yarns 36a and the two weft yarns 36b is A2.
In the perforated belt 18, the yarns that form the textile are not fused at all intersecting portions 35. That is, only part of the intersecting portions 35 are fused, in such a manner that, at least in a longitudinal direction (circumferential direction) of the perforated belt 18, fused regions 37, where fused intersecting portions 35 are adjacent to each other, and non-fused regions 38, where non-fused intersecting portions 35 are adjacent to each other, are alternately arranged. In this embodiment, the fused regions 37 and the non-fused regions 38 are provided so as to alternate also in a direction of the width of the perforated belt 18. More specifically, as shown in Fig. 1C, a perforated belt 18 on which no fusing process has been carried out is a cylindrical textile that is uniform throughout its entirety, while a perforated belt 18 on which a fusing process has been carried out is formed in such a manner that, as illustrated in Fig. 1B, circular fused regions 37 are distributed approximately uniformly throughout the entirety of the perforated belt 18, and the non-fused regions 38 form the remaining region. Further, in Fig. 1B, the warp yarn 36a and the weft yarn 36b are not shown.
Each fused regions 37 contains not only fused intersecting portions 35, but also apertures surrounded by fused intersecting portions 35, and each non-fused region 38 contains not only non-fused intersecting portions 35, but also apertures surrounded by non-fused intersecting portions 35. When the intersecting portions 35 are fused, the thermally fusing yarns 34 are melted also in the vicinity of the intersecting portions 35, and therefore, the aperture ratio in the fused regions 37 becomes lower than the aperture ratio in the non-fused regions 38. In addition, the appearances of the fused regions 37 and the non-fused regions 38 are different, and, as shown in Fig. 1B, the fused regions 37 appear to be in a state which is distinguishable from that of the non-fused regions 38.
The ratio of fused regions, which is the ratio of the total area of the fused regions 37 in relation to the total area of the surface of the perforated belt 18, that is to say, in relation to the sum of the combined total area of the fused regions 37 and the non-fused regions 38, is preferably between 50% and 95%, and more preferably between 70% and 90%. In cases where the ratio of fused regions is less than 50%, the durability of a perforated belt 18 tends to become inadequate, while in cases where the ratio of fused regions exceeds 95%, pliancy of a perforated belt 18 tends to become inadequate. Further, regarding the size of a single fused region 37, though this depends on the width of the perforated belt 18, in a case where the fused regions 37 are circular, the diameter is preferably no greater than half of the width of the perforated belt 18 and the area is preferably no greater than 100 mm².
Next, a manufacturing method for the perforated belt 18 will be described. Productivity is modest in a case where the perforated belt 18 is initially formed so as to have the same width as the final product, and then a fusing process is carried out for the manufacture. Therefore, a cylindrical textile having a length that is a number of times (for example several tens of times) greater than the width of the final product should first be prepared. Since the width of a perforated belt 18 is approximately 15 mm to 25 mm, a cylindrical textile having a length of several hundreds of millimeters should be prepared. Then, as shown in Fig. 3, a fusing process is carried out by means of an apparatus with a fusing process portion 40 where a number of holes 40b are created in a cylindrical body 40a of which the outer diameter is approximately the same as the inner diameter of the cylindrical textile 39. The cylindrical body 40a is formed so as to be longer than the cylindrical textile 39, and holes 40b are created in an area that is greater than the length of the cylindrical textile 39. The holes 40b are created so as to have a size that matches the fused regions 37 of the perforated belt 18, and in locations corresponding to the state of distribution of the fused regions 37. One end of the cylindrical body 40a is closed.
A high temperature gas (for example, air) that is capable of melting the sheath portion 34a of the thermally fusing yarns 34 is supplied inside the cylindrical body 40a of the fusing process portion 40 in a state where the cylindrical textile 39 is engaged with the cylindrical body 40a from the outside. The high temperature gas that has been supplied within the cylindrical 40a is blown from the holes 40b to the outside of the cylindrical body 40a. Then, the sheath portions 34a are fused in the intersecting portions 35 of the thermally fusing yarns 34 in the regions of the portions corresponding to the holes 40b of the cylindrical textile 39, and thus, fused regions 37 are formed. After a high temperature gas has been supplied into the cylindrical body 40a over a predetermined period of time, the cylindrical body 40a is cooled. After cooling has been completed, the cylindrical textile 39 is removed from the cylindrical body 40a. After that, the cylindrical textile 39 is cut into a predetermined width, and thus, the perforated belts 18 are completed.
A perforated belt 18 in which fused regions 37 are formed into a desired state can be manufactured by adjusting the size, the number and the state of distribution of the holes 40b which are created in the cylindrical body 40a.
Next, an explanation will be given of the functions of the fiber bundle concentrating device 11 that is formed in the manner described above.
When the fine spinning machine is operated, fiber bundles F are drafted in the draft machine 12, and after that, guided from delivery roller pairs 13 to the fiber bundle concentrating device 11. The nip roller pairs 16 are rotated slightly faster than the surface speed of the final delivery roller pairs 13, and thus, each fiber bundle F passes through the nipping point of the corresponding nip roller pair 16 in a state such as to have an appropriate degree of tension, and after that, changes in direction and moves to the downstream side while being twisted.
Furthermore, the suction in the duct acts on the suction pipes 29 and 30 via the connecting tube 31, and then, the suction through the suction holes 29a and 30a, which are formed in the guide surfaces 29b and 30b, acts on the fiber bundles F by way of the perforated belt 18. Then, the fiber bundles F move to a position corresponding to the suction holes 29a and 30a in a sucked and concentrated state. Accordingly, in contrast to spinning machines which are not equipped with the fiber bundle concentrating device 11, the quality of yarns is enhanced by preventing the production of fluff and cotton waste.
This embodiment has the following advantages.

(1) In each perforated belt 18 which rotates in a state such as to make contact with the guide surfaces 29b and 30b of the suction pipes 29 and 30 that form the fiber bundle concentrating device 11, the yarns that form the textile, which is a body in sheet form made of a material for the belt (thermally fusing yarns 34), is fused at part of the intersecting portions 35. Accordingly, even in cases where the yarns that form the textile break, the ends of the broken yarns are prevented from becoming entangled with the spun fiber bundles F that have been delivered, and fibers of the spun fiber bundles F that have been delivered are prevented from being pinched in the intersecting portions 35 of the yarns. Consequently, the process of concentrating and transporting the fiber bundles F is prevented from deteriorating in quality, and the spun fibers of the yarns that have been delivered to form the perforated belts 18 are prevented from being pinched between intersecting portions 35, or being attached to them. The process of spinning and delivery can thereby be improved.
(2) The fused regions 37, where the fused intersecting portions 35 are adjacent to each other, and the non-fused regions 38, where the non-fused intersecting portions 35 are adjacent to each other, are alternately arranged at least in a longitudinal direction (circumferential direction) of each perforated belt 18. Accordingly, in contrast to perforated belts having a configuration where all intersecting portions 35 are fused, pliancy is maintained for the perforated belt 18. Thus, the perforated belt 18 moves smoothly in a state where it follows the outer shapes (guide surfaces 29b and 30b) of the suction pipes 29 and 30, which serve as guiding portions in the fiber bundle concentrating device 11, and therefore, the process of concentrating and transporting the fiber bundles F is prevented from deteriorating.
(3) The fused regions 37 and the non-fused regions 38 are provided so as to alternate also in a direction of the width of the perforated belt 18, and therefore, pliancy in the direction of the width of the perforated belt 18 is also enhanced.
(4) The ratio of the total area of fused regions 37 relative to the total area of the perforated belt 18 is between 50% and 95%. Accordingly, the pliancy is maintained for the perforated belt 18, and durability is also enhanced. In addition, it is more preferable for the above ratio to be between 70% and 90% in order to ensure the pliancy and enhance durability of the perforated belt 18.
(5) The yarns that form the perforated belt 18 are made of polyamide. Accordingly, the necessary strength can be secured, even in cases where the thickness of the yarns is made approximately 0.1 mm, in order to make a thin perforated belt 18. In addition, polyamide is compatible with cotton, and spinning and delivery are thus carried out smoothly.
(6) The thermally fusing yarns 34 are used to provide a sheath-core structure for the yarns that form the textile (a sheet body) which serves as a material for the perforated belt 18. Accordingly, the yarns that form the textile are easily fused at intersecting portions 35.
(7) In the textile which serves as a material for the perforated belt 18, thermally fusing yarns 34 are used for both the warp yarns 36a and the weft yarns 36b. Accordingly, in contrast to cases where only either the warp yarns 36a or the weft yarns 36b are made of thermally fusing yarns 34, the yarns are easily fused in the intersecting portions 35.
(8) The perforated belt 18 is finely woven with fine yarns of approximately 0.1 mm. The suction of the fiber bundles F is accordingly efficient.
(9) The perforated belt 18 is in a seamless loop form. The fiber bundles F are therefore transported smoothly, and fatigue can be prevented from easily spreading from any seam.
(10) The textile for forming the perforated belt 18 is woven with filament yarns. The degree of strength is accordingly high in comparison with staple yarns of the same thickness, and aeration is enhanced.
(11) For undertaking a fusing process that is required for the manufacture of the perforated belt 18, a method is adopted of blowing out a high temperature gas through the holes 40b in a state where the cylindrical textile 39 is engaged from the outside with the cylindrical body 40a in which the holes 40b have been created. Accordingly, the cylindrical body 40a is used in which the holes 40b have been created in a state that conforms to the size and the distribution of the fused regions 37 to be formed. The perforated belt 18 having the fused regions 37 of desired configuration is easily manufactured at an enhanced productivity.

The embodiments are not limited to the above, and may also be modified as follows.
The perforated belt 18 is not limited to a configuration in which the fused regions 37 are distributed uniformly throughout the entirety of the perforated belt 18, and the perforated belt 18 may be formed in such a manner that the ratio of the area of the fused regions 37 on the end portions in a widthwise direction is higher than the ratio of the area of fused regions 37 in the widthwise center portion. In this context, "end portions in a widthwise direction" means a range of from 1/4 to 1/3 from the ends in the widthwise direction, and the widthwise center portion is the remaining range of 1/2 to 1/3. In addition, "ratio of the area of the fused regions 37" means the ratio of the area of the fused regions 37 relative to the total combined area of the fused regions 37 and the non-fused regions 38. As methods of increasing the ratio of the area of fused regions 37 on the end portions, a method exists of varying the density of fused regions 37 having an identical size, as well as a method of forming fused regions 37 of varying sizes and modifying the density. As the ratio of the area of fused regions 37 in the center becomes smaller, the aperture ratio becomes greater, and in a case where the ratio of fused regions 37 is the same throughout the entirety of the perforated belt 18, the suction of the fiber bundles F is more effective compared to cases where the fused regions 37 are distributed approximately uniformly throughout the entirety of the perforated belt 18.
In the configuration where fused regions 37 of different sizes are provided on the end portions and in the center, if the ratio of the area on the end portions is higher, it is preferable that, as shown in Fig. 4A, fused regions 37 of a large area are formed on the end portion side, and fused regions 37 of a small area are formed in the center. In such cases, suction through suction holes 29a and 30a uniformly acts on the fiber bundles F.
The number of the fused regions 37 aligned in the direction of the width of the perforated belt 18 may be the same for each column in the arrangement. In addition, fused regions 37 having different sizes may be mixed in the arrangement.
The form of the fused regions 37 is not limited to a circular form, and may be changed to an appropriate form, so as to be for example, polygonal, triangular, quadrilateral, or elliptical.
As illustrated in Fig. 4B, fused regions 37 which extend intermittently in the circumferential direction may be formed at both widthwise ends of the perforated belt 18. In such cases, the presence of non-fused regions 38 between the fused regions 37 ensures the pliancy of the perforated belt 18, and the end portions of the perforated belt 18 are less likely to become frayed.
The fusing process of the intersecting portions 35 at the time of manufacturing the perforated belt 18 is not limited to the method in which a high temperature gas is blown out through the holes 40b of the cylindrical body 40a. A method may, for example, be adopted of engaging the cylindrical textile 39 with a roller from the outside, pressing another roller that has protrusions in the same form as the fused regions 37 against the cylindrical textile 39 and rotating the rollers in this state while heating them. However, the method in which a high temperature gas is used is easier.
A fusing process may be carried out on the cylindrical textile 39 which is formed to have the same width as the final product, or the perforated belt 18.
The perforated belt 18 is not limited to a belt formed of a textile of plain weave, and textiles woven, for instance, as twill weave may be used.
The perforated belt 18 is not limited to a belt formed of a textile, and may be formed of a knit (knitted fabric). In such cases, because of the elasticity of the knitted fabric, a tension apparatus need not be particularly provided in order for the perforated belt 18 to be rotated in a state of appropriate tension.
The perforated belt 18 is not limited to a fabric or a knit, and as in the case of the unwoven sheet disclosed in Japanese Laid-Open Patent Publication 2004-346472 , may be formed of a body in a sheet form where two layers of yarns, each of which is formed of yarns aligned in one direction (thermally fusing yarns 34), are laid on top of each other in a state in which the directional alignment of the thermally fusing yarns 34 is such that they cross one another (for example in a perpendicular state) and part of the respective intersecting portions 35 of the thermally fusing yarn 34 are fused.
The perforated belt 18 is not limited to being in an endless, seamless loop formed of a textile or knit that is woven or knitted, and may be in loop form with a seam, in which the two ends of a textile or knit in a band form are adhered to each other.
Instead of the entirety of the yarns of the textile being made of thermally fusing yarns, only the warp yarns or the weft yarns of the fabric for forming the perforated belt 18 may be made of thermally fusing yarns.
The thermally fusing yarns 34 are not limited to a type in which the sheath portions 34a and the core portions 34b are both made of polyamide. Thermally fusing yarns, in which both the sheath portions 34a and the core portions 34b are made of polyester, or thermally fusing yarns, in whch the sheath portions 34a are made of polyester and the core portions 34b are made of polyamide, may be used.
The perforated belt 18 may have an antistatic function.
In the illustrated embodiment, each unit of the rotary shafts 19 and the suction pipes 29 and 30 corresponds to four of the spindles. However, each unit may correspond to the spindles between the roller stands 22 (for example, eight spindles), or to two spindles. In addition, all units need not necessarily correspond to the same number of the spindles. That is, thee spindles between roller stands 22 may be divided into two groups of different numbers of spindle (for example, six spindles and two spindles), and two types of units may be provided.
The configuration is not limited to one in which the suction holes 29a and 30a are provided on the upstream side and on the downstream side of the nipping point of the fiber bundle F, and the configuration may have suction pipes 29 with suction holes 29a only upstream from the nipping point. In such cases, instead of the suction pipes 30 pipes, bars may be used that have the same outer shape as the suction pipes 30 and in which no suction holes 30a are formed. The method of manufacturing or assembling can accordingly be substantially identical to that in the embodiment described above. In addition, the perforated belt 18 may be wrapped around the suction pipe 29 and the bottom nip roller 19a without a suction pipe 30.
The delivery portion of the fiber bundle concentrating device 11 is not limited to a configuration where the nip roller pairs 16 are installed. As illustrated in Fig. 5, for example, a suction pipe 44 may be provided of which a cross section is approximately egg-shape, and suction holes 44a may be created in predetermined locations in the suction pipe 44. The perforated belt 18 is wrapped around the outer periphery of the suction pipe 44 and the tension roller 45 so as to be slidable. In addition, the rotation of the front top roller 15 is transmitted to the top nip roller 20 by way of the gear 46, so that the top nip roller 20 is driven while being pressed against the perforated belt 18, and the perforated belt 18 is thereby driven.
A common rotary shaft 19 with bottom nip rollers 19a may be used for all the spindles, so as to be driven by a motor via gears which are provided at the gear end of the fine spinning machine, in the same manner as the front bottom rollers 14 of the draft machine 12.
The perforated belt 18 may be provided at the top side.
The invention may be applied to a draft machine for other types of spinning machines and is not limited to a draft machine for a fine spinning machine.
Therefore, the present examples and embodiments are to be considered as illustrative and not restrictive and the invention is not to be limited to the details given herein, but may be modified within the scope and equivalence of the appended claims.

Claims

A fiber bundle concentrating device in a spinning machine, the device concentrating fiber bundles (F) drafted by a draft part (12), the device comprising:
a fiber bundle delivery portion including a nip roller (19a, 20), the fiber bundle delivery portion being located downstream of a final delivery roller pair (13) of the draft part;

a suction portion (17) having a guide surface (29b), wherein the guide surface (29b) has a suction hole (29a) at least in a section upstream of a nip point of the delivery portion in a moving direction of the fiber bundles; and

a perforated belt (18) that rotates while sliding on the guide surface, wherein the perforated belt is formed as a sheet body that contains intersecting sets of yarns (34), the fiber bundle concentrating device being characterized in that:
part of intersecting portions (35) of the yarns are fused such that fused regions (37), where the fused intersecting portions (35) are adjacent to each other, and non-fused regions (38), where the non-fused intersecting portions are adjacent to each other, are alternately arranged at least in a circumferential direction of the perforated belt.
The fiber bundle concentrating device according to claim 1, characterized in that the fused regions (37) and the non-fused regions (38) are alternately arranged in a widthwise direction of the perforated belt (18).
The fiber bundle concentrating device according to claim 1 or 2, characterized in that the ratio of the total area of the fused regions (37) to the total area of the surface of the perforated belt (18) is 50% to 95%, inclusive.
The fiber bundle concentrating device according to any one of claims 1 to 3, characterized in that the yarns are made of polyamide.
The fiber bundle concentrating device according to any one of claims 1 to 4, characterized in that the perforated belt (18) is formed in such a manner that the ratio of the area of the fused regions (37) in a widthwise end portion of the perforated belt (18) is higher than the ratio of the area of the fused regions (37) in a widthwise center portion.
A method for manufacturing a perforated belt, characterized by:
forming a cylindrical sheet body with intersecting sets of yarns (34), wherein the yarns (34) in at least one of the sets are thermally fusing yarns; and

engaging the sheet body with a cylindrical body (40a) having a closed end from the outside, the cylindrical body (40a) having a plurality of holes (40b) in a circumferential surface, and supplying into the cylindrical body a gas of a temperature that is equal to or higher than the melting point of the thermally fusing yarns, thereby fusing the intersecting yarns to each other at positions of the sheet body that correspond to the holes by the heat of the gas blown out of the holes.
The method according to claim 6, characterized in that the sheet body has a width that is a multiple of the width of a finally produced perforated belt (18), wherein, after the fusing of the intersecting yarns (34) is completed, the sheet body is cut to form a plurality of perforated belts.