|
(11) | EP 1 548 162 A2 |
| (12) | EUROPEAN PATENT APPLICATION |
|
|
|
|
|||||||||||||||||||||||
| (54) | Drafting apparatus with fiber feeding means having longer service lifetime |
| (57) Provided is a drafting apparatus to achieve a longer lifetime in service of a front
roller therein, to realize labor-saving in spinning operation and to improve an operation
efficiency. A drafting apparatus D includes a pair of fiber feeding means for transporting
a sliver F to the downstream side while grasping the sliver F at a nip point N and
stretching it, characterized in that one of the pair of fiber feeding means is constituted
of an endless belt 12, and the pair of fiber feeding means is provided so that a feeding
force acting in a direction of feeding the fiber bundle with the endless belt is concentrated
on the nip point. |
[Technical Field]
[0001] This invention concerns a drafting apparatus constructed in a way such that a fiber bundle is transported to the downstream side while stretched, and particularly, to improvement on fiber feeding means in the drafting apparatus.
[Related Background Art]
[0002] As well known, a drafting apparatus, as shown in Fig. 3, has been installed in a yarn manufacturing machine such as a spinning machine constituted of a drafting apparatus D and a spinning member S downstream thereof and besides in a fiber processing machine such as a roving machine and a slivering machine. The drafting apparatus D in a spinning machine as an example thereof includes : plural pairs of drafting rollers, which constitutes pairs of fiber feeding means. The drafting rollers are for use in drafting a sliver F and constituted of, for example, a pair of front rollers Rf, a pair of second rollers R2 having aprons, a pair of third rollers R3 and a pair of back rollers Rb. Each of the pairs of rollers is a combination of a top roller 2 and a bottom roller 3. A top roller and bottom roller of each of the pairs are in contact with each other and rotates in opposed directions. Therefore, a sliver is guided into between a top roller and bottom roller and can be drafted by the top roller and bottom roller, and a drafted fiber bundle is delivered from the pair of front rollers Rf of the drafting apparatus D.
[0003] In a conventional drafting apparatus D as described above, the drafting rollers have been rubber rollers, which are disclosed in Patent Document 1 and Patent Document 2. Rubber rollers used as sliver feeding means has had a problem of shortness of a lifetime in service and lowering physical properties of a yarn, which compels an operator to do an exchange operation at a short time or operations of repolishing, an ultraviolet treatment and the like.
[Patent Document 1] JP-A No. 11-189933 (paragraph 0010, Fig.3)
[Patent Document 2] JP-A No. 11-279854 (Figs. 1 and 2)
DISCLOSURE OF THE INVENTION
[0004] The invention has been made in order to solve the problem of the prior art and it is an object of the invention to provide a drafting apparatus, one of a pair of fiber feeding means constituting which is formed with an endless belt as an especially important element to thereby achieve a longer lifetime in service of a front roller Rf, to realize labor-saving in spinning operation and to improve an operation efficiency.
[0005] The invention of this application, in order to achieve the object, is directed, to be concrete, to a drafting apparatus including a pair of fiber feeding means for transporting a fiber bundle to the downstream side while grasping the fiber bundle at a nip point and stretching it, characterized in that one of the pair of fiber feeding means is constituted of an endless belt, and the pair of fiber feeding means is provided so that a feeding force acting in a direction of feeding the fiber bundle with the endless belt is concentrated on the nip point.
[0006] Further, in this invention, the invention set forth in claim 2 is the drafting apparatus set forth in claim 1, characterized in that a tension is imparted to the endless belt in state of being wound around at least two pulleys, one of the at least two pulleys works to bring the endless belt into contact with the nip point so as to form the nip point, the at least two pulleys are disposed so that a direction in which the endless belt extends between the at least two pulleys intersects with a direction in which the fiber bundle is fed and the endless belt is wound around the at least two pulleys.
[0007] Moreover, in this invention, the invention set forth in claim 3 is the drafting apparatus set forth in claim 1 or 2, characterized in that plural pairs of feeding means thereof provided so as to be higher in feed speed of a pair of feeding means toward the downstream, wherein the endless belt is disposed in a pair of fiber feeding means having the highest fiber feed speed in the most downstream side.
[0008] Moreover, in this invention, the invention set forth in claim 4 is the drafting apparatus set forth in claim 3, characterized in that the pulley for bringing the endless belt into contact with the nip point has protrusions formed outwardly from the both ends of the endless belt in the width direction thereof and level difference portions are formed between the protrusions and a contact portion at the nip point of the endless belt.
[0009] Moreover, in this invention, the invention set forth in claim 5 is the drafting apparatus set forth in any of claims 1 to 4, characterized in that the pair of fiber feeding means one of which is constituted of an endless belt is used in a spinning machine installedwith a spinning member twisting a drafted fiber bundle with the action of a vortex air stream thereon.
[0010] Moreover, in the invention, the invention set forth in claim 6 is the drafting apparatus set forth in claim 5, characterized in that the spinning member is constituted of an air-spin nozzle generating a vortex air stream and a hollow guide shaft having a passage for a produced yarn.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011]
Fig. 1 is a side view schematically showing a main section of a spinning machine combined with a drafting apparatus according to the invention.
Figs. 2A and 2B show an example of the drafting apparatus in which an endless belt is applied to the top side of a pair of a first feeding means, wherein Fig. 2A is a plan view schematically showing a main portion thereof and Fig. 2B is a cross sectional view of part of the endless belt together with related portions thereof.
Fig. 3 is a side view schematically showing a main section of a spinning machine combined with a conventional typical drafting apparatus.
Fig. 4 is a perspective view schematically showing a main section of a first spinning machine to which a drafting apparatus related to the invention is applied.
Fig. 5 is a sectional side view schematically showing a relationship a pair of first feeding means forming a nip point and a spinning member in the first spinning machine to which a drafting apparatus related to the invention is applied.
BEST MODE FOR EMBODYING THE INVENTION
[0012] Detailed description will be given of a drafting apparatus according to the invention below based on concrete examples shown in the accompanying drawings. Fig. 1 is a side view schematically showing a main section of a spinning machine combined with a drafting apparatus according to the invention. Figs. 2 A and 2B show an example of the drafting apparatus in which an endless belt is applied to the top side of a pair of a first feeding means Rf, wherein Fig. 2A is a plan view schematically showing a main portion thereof and Fig. 2B is a cross sectional view of part of the endless belt together with related portions thereof.
[0013] According to the invention, in a drafting apparatus D including a pair of fiber feeding means for transporting a sliver F to the downstream side while grasping the sliver F at a nip point N and stretching it, not only is the top side of a pair of first fiber feedingmeans Rf constituted of endless belt means 11 including an endless belt 12, but a force imparting means 13 imparting a force to the endless belt 12 is also provided so that a feeding force in a direction in which the sliver F is fed is concentrated on the nip point N.
[0014] The endless belt means 11 in the pair of first feed means Rf includes the endless belt 12 and at least two pulleys 14 and 15 and a tension is imparted to the endless belt 12 in a state of being wound around the at least two pulleys 14 and 15. In the example shown in Figs. 1, and 2A and 2B, the pulley 14 brings the endless belt 12 into contact with the nip point N so as to form the nip point N, which can be realized with a configuration in which a line EL in a direction in which the endless belt means 11 spanned over the two pulleys extends intersects with a direction FD in which the fiber bundle is fed. In such a way, by disposing the endless belt 12 so that a sliver F is brought into contact with the endless belt 12 only at the nip point N and the feeding force in a direction in which the sliver F is fed concentrates on the nip point N, a time consumed in which one point on the endless belt 12 and the sliver F are again brought into contact with each other is extended to delay progress in wear, thereby enabling a longer lifetime in service to be realized. Furthermore, since contact between the belt 12 and the sliver F is concentrated to the nip point N, a contact portion of the belt 12 with the sliver F is minimized, thereby enabling progress in wear thereof to be further delayed.
[0015] In the invention, plural pairs of fiber feeding means include: a pair of first feeding means Rf; a pair of second feeding means R2 having aprons; a pair of third feeding means R3 and a pair of fourth feeding means Rb in the order from the downstream side, wherein each of the pairs of second, third and fourth feeding means R2, R3 and Rb are constituted of a top roller 2 and bottom roller 3 combined and the pair of first feeding means Rf is constituted of the endless belt means 11 and a bottom roller 3 combined. Each of these pairs of fiber feeding means is higher in speed toward the downstream side. The endless belt 12 is composed of a pair of fiber feeding means having the highest fiber feed speed in the most downstream side, that is disposed in the pair of first feeding means Rf.
[0016] As examples to which a drafting apparatus related to the invention is applied, presented are techniques concerning a spinning member capable of high speed spinning at 200 m/min or higher by twisting a sliver F with the action of a vortex air stream. To be detailed, the well-known techniques are as follows:
(1) A technique in which a yarn is produced with a hollow guide shaft and a air-spin nozzle (with a spinning speed of 300 m/min or higher), disclosed in, for example, JP-A-Nos. 2001-164432 and 2002-227043.
(2) A technique in which a fasciated yarn is produced with the action of two opposed vortex air streams (with a spinning speed in the range of from 200 to 300 m/min) , disclosed in, for example, JP No. 3185393 and JP-A No. 8-209463.
(3) A technique in which a fasciated yarn is produced with the action of an air-spin nozzle and a roller type false twisting apparatus (with a spinning speed in the range of from 300 to 350 m/min), disclosed in, for example, JP-A Nos. 11-279854 and 8-209463.
[0017] Description will be given of a spinning member using a vortex air stream with a construction in which a yarn is produced with the action of the hollow guide shaft and the air-spin nozzle described in the item (1) based on Fig. 5. The spinning member S is, as shown in Fig. 5, constituted of a nozzle block 4 and a hollow guide shaft 5, the spinning member S in which a drafted sliver F is fed to the nozzle block 4 and the hollow guide shaft 5. The nozzle block 4 has an air-spin nozzle 6, and a sliver F is influenced by a vortex air stream from the air-spin nozzle at the distal end of the hollow guide shaft 5 and then guided into a yarn passage 7 in the hollow guide shaft 5. Thereby, a truly twisted-like spun yarn is spun to produce a yarn Y. Thus produced yarn Y is guided to a take-up drum 8 by way of a delivery roller Rd and wound thereon as a wound package 9. A structure of a yarn Y is defined by a ratio in peripheral speed between the front roller Rf and the delivery roller Rd, that is an expansion/shrinkage degree in the spinning member S.
[0018] In the spinning machine described in the item (3), as shown in Fig. 4, a sliver F is drafted through the front roller Rf, the second roller R2 and the third roller R3, thereafter, guided into an air nozzle S1 and a pair of twisting rollers T constituting a spinning member S and a fiber bundle is twisted by a cooperative action of the air nozzle S1 and the twisting rollers T. A twisting efficiency of the combination is high with the result that a yarn can be spun at a high speed (200 m/min or higher). The effect of a longer lifetime in service in the invention is more conspicuous with a higher spinning speed, that is with a higher feed speed of the drafting apparatus D.
[0019] In a case of a high speed spinning at a spinning speed of 200 m/min or higher, in the drafting apparatus, a sliver F passes through between a top apron and bottom apron of the second roller R2 and guided to the front roller Rf, at which time diffusion of a fiber bundle occurs by the action of an accompanying air stream reaching the nip point N on the front roller Rf, arising a tendency of poor uniformity in spinning.
[0020] In the invention, therefore, a pulley 14 for bringing the endless belt 12 into contact with the nip point N has the protrusions 16 and 17 formed outwardly from the both ends 12a and 12a of the endless belt 12 in the width direction thereof and the level difference portions d are formed between each of the protrusions 16 and 17, and the contact portion at the nip point N of the endless belt 12. That is, if an outer diameter of the pulley 14 is set to φ1, an outer diameter of the protrusions 16 and 17 is set to φ2 and a thickness of the endless belt 12 is set to t by definition, the level difference portions d are formed if setting is made so as to establish a relation of [ ( φ2 - φ1) /2] < t. With such a structure adopted, the accompanying air stream is escaped from the level difference portions d to thereby prevent a feed of a sliver F from being put in disorder, which results in the effects not only of realization of a longer lifetime in service but also of prevention of lowering in physical properties of a yarn. All of the above discussions being considered, in the embodiment, by suppression of a change with time in feeding of a sliver F accompanied by the use of members over a long term and an instant change in feeding of a sliver F caused by the accompanying air stream, a change in feeding a sliver F can be the smallest possible level. Therefore, in the embodiment, a stable drafting is ensured to thereby enable a uniform yarn quality to be obtained all the time.
[0021] Note that while in the embodiment, description is given of a case where a drafting apparatus D related to the invention is applied to a spinning machine using a vortex air stream, the invention is not limited the this application and can also applied to any of fiber processing machines each installed with a drafting apparatus such as a roving machine, slivering machine and a ring fine spinning machine.
[0022] In a conventional drafting apparatus using rubber rollers, the rubber rollers are rotatably supported by and mounted on shafts with bearings or the like interposed therebetween, which has caused a problem that in a step of exchange, a complex operation is required, while with the endless belt 12 adopted in the apparatus as in the invention, the endless belt 12 is only released from the tension state imparted by the pulleys 14 and 15, which enables the endless belt 12 to be exchanged with ease, thereby further enabling improved maintenance to be realized.
[Industrial Applicability]
1. A drafting apparatus including a pair of fiber feeding means for transporting a fiber
bundle to the downstream side while grasping the fiber bundle at a nip point and stretching
it, characterized in that one of the pair of fiber feeding means is constituted of an endless belt, and the
pair of fiber feeding means is provided so that a feeding force acting in a direction
of feeding the fiber bundle with the endless belt is concentrated on the nip point.
2. The drafting apparatus set forth in claim 1, characterized in that a tension is imparted to the endless belt in state of being wound around at least
two pulleys, one of the at least two pulleys works to bring the endless belt into
contact with the nip point so as to form the nip point, the at least two pulleys are
disposed so that a direction in which the endless belt extends between the at least
two pulleys intersects with a direction in which the fiber bundle is fed and the endless
belt is wound around the at least two pulleys.
3. The drafting apparatus set forth in claim 1 or 2, characterized in that plural pairs of feeding means thereof provided so as to be higher in feed speed of
a pair of feeding means toward the downstream, wherein the endless belt is disposed
in a pair of fiber feeding means having the highest fiber feed speed in the most downstream
side.
4. The drafting apparatus set forth in claim 3, characterized in that the pulley for bringing the endless belt into contact with the nip point has protrusions
formed outwardly from the both ends of the endless belt in the width direction thereof
and level difference portions are formed between the protrusions and a contact portion
at the nip point of the endless belt.
5. The drafting apparatus set forth in any one of claims 1 to 4, characterized in that the pair of fiber feeding means one of which is constituted of an endless belt is
used in a spinning machine installed with a spinning member twisting a drafted fiber
bundle with the action of a vortex air stream thereon.
6. The drafting apparatus set forth in claim 5, characterized in that the spinning member is constituted of an air-spin nozzle generating a vortex air
stream and a hollow guide shaft having a passage for a produced yarn.