DESC:

TECHNICAL FIELD OF THE INVENTION
[1] The present invention relates to an improved drafting arrangement in textile spinning machines. Also, the present invention relates to a guide element for top rollers in textile spinning machines.
BACKGROUND OF THE INVENTION
[2] In the known drafting arrangements of textile spinning machines, bottom rollers are set to be stationary, while top rollers mounted on a saddle unit. The top rollers are moved transversely to the longitudinal direction of the machine, to change the draft setting. The said draft setting takes place, whenever the length of the fiber material being processed is changed. While adjusting the draft setting distances, the axis of the top rollers must be aligned properly parallel with respect to the axis of respective bottom rollers and other top rollers of drafting unit of the spinning machine. The failure to maintain the parallelism that happens due to oscillation or tilting of the axle of the top rollers is shown in figure 1. Figure 1 illustrates the drafting arrangement (1’), in which, after the process of adjusting the draft setting distances between the top rollers (2’ and 3’) and during machine running, the axis of the top rollers (2’ and 3’) is not maintained parallel with respect to the axis of respective bottom rollers (2” and 3”) and other top rollers due to the oscillation or tilting of the top rollers (2’ and 3’). The said oscillations of top rollers (2’ and 3’) are caused by draft setting process, done by the operating persons already, during the machine running conditions. The said oscillations of the top rollers (2’ and 3’) also happen due to the lapping of fibre materials on the outer surfaces of the top rollers (2’ and 3’). The said tilting or oscillation of the top rollers during the machine running causes serious problems like spindle to spindle yarn count variations and yarn imperfections between the spinning stations in the textile spinning machines.
[3] Further, it is reported in the art that in a drafting arrangement of the spinning machines, in order to prevent the oscillations and swinging of top rollers during the lapping of top rollers surface in regular running conditions in the top arm, each top rollers is provided with metal fitting fixed directly to both sides of the cradle arm. However, it is difficult to adjust the draft setting distances between the top rollers since the metal fittings are directly mounted on the top arm and the same cannot be employed in the drafting system of the spinning machines.
[4] In addition, it is also reported in the art that in the drafting arrangement of the spinning machines, the drafting system is provided with a catch bearing arranged on the axle of the top pressure roller. The said catch bearing limits the twin pressure roller in its oscillation motion whenever the oscillation angle exceeds a certain range during the lifting and placing of the top arm on the bottom rollers. Also, the catch bearing of the holding element is constantly loaded with a pressing force by a loading device provided in the drafting system. However, the problem of the tilting of the top rollers during the draft setting process and lapping of top rollers in the drafting system of spun yarn drafting system that is used in ring spinning machines is not yet addressed.
[5] Therefore, there is a need to provide a drafting arrangement in textile spinning machines that overcomes the aforementioned problems.

SUMMARY OF THE INVENTION
[6] In an aspect, the present invention provides an improved drafting arrangement in textile spinning machines to prevent the tilting or oscillatory movements of top rollers during the draft setting process.
[7] The drafting arrangement of the present invention comprises a plurality of top rollers rotatably arranged over a plurality of bottom rollers. Each top roller comprises axle having axle centre portion and axle end portion. A top arm is mounted on a shaft provided in the spinning machine. A saddle for each top roller is slidably mounted on said top arm. Each saddle comprises a top roller supporting portion for mounting the axle centre portion of said top roller. A guide element for each top roller is mounted fixedly on the saddle. The guide element has a hook like structure covering the axle and arranged at a distance from the axle in such a way that the guide element maintains the axis of each top roller in perpendicular to the axis of top arm and parallel to respective bottom rollers and rest of the top rollers by preventing tilting or oscillatory movements of the top rollers during and after the draft setting process and during lapping of top rollers in running conditions.
[8] In accordance with the embodiments of the present invention, the guide element (8) preferably covers more than 50% of the circumferential portion of said axle end portions of the top roller .
[9] In accordance with the embodiments of the present invention, the guide element is made from a single plate covering one or two opposite side of the top rollers. In another embodiment, the guide element is made from two separate plates covering one or two opposite sides of the top rollers .
[10] In accordance with the embodiments of the present invention, the guide element is made from a plastic or a metal or a composite material.
[11] In accordance with the embodiments of the present invention, the guide element has at least two insertion holes corresponding to the fitting holes for connecting the guide element by screws or bolts and nuts.
[12] In another aspect, the present invention also relates to a guide element for a plurality of top rollers in textile spinning machines. The guide element comprises a hook like structure covering the axle and arranged at a distance from the axle in such a way that the guide element maintains the axis of each top roller in perpendicular to the axis of top arm and parallel to respective bottom rollers and rest of the top rollers by preventing tilting or oscillatory movements of the top rollers during the draft setting process and during lapping of top rollers in running conditions.

BRIEF DESCRIPTION OF ACCOMPANYING DRAWINGS
[13] The above and other aspects, features, and advantages of certain exemplary embodiments of the present invention will be more apparent from the following description taken in conjunction with the accompanying drawings in which:
Figure 1 illustrates the top view of drafting arrangement showing top roller in tilted condition of the prior art;
Figure 2 illustrates the side view of the drafting arrangement in accordance with the present invention;
Figure 3 illustrates the top view of the drafting arrangement in accordance with the present invention;
Figure 4 illustrates an exploded view of the drafting arrangement showing the parts of the drafting arrangement in accordance with the present invention; and
Figure 5 illustrates an exploded view of a drafting top roller, guide element and saddle in drafting arrangement in accordance with the present invention.
DETAILED DESCRIPTION OF THE INVENTION:
[14] The following description with reference to the accompanying drawings is provided to assist in a comprehensive understanding of the invention as defined by the description. It includes various specific details to assist in that understanding but these are to be regarded as merely exemplary. In addition, descriptions of well-known functions and constructions are omitted for clarity and conciseness.
[15] The terms and words used in the following description are not limited to the bibliographical meanings but are merely used by the inventor to enable a clear and consistent understanding of the invention. Accordingly, it should be apparent to those skilled in the art that the following description of the present invention is provided for illustration purpose only.
[16] It is to be understood that the singular forms “a”, “an” and “the” include plural referents unless the context clearly dictates otherwise.
[17] The present invention discloses an improved drafting arrangement in textile spinning machines to prevent the tilting or oscillatory movements of top rollers during the draft setting process. Referring to Figures 2-5 of the drawings, a drafting arrangement (1) in textile spinning machines is provided in accordance with the embodiments of the present invention. The drafting arrangement (1) comprises a plurality of top rollers (1b, 2b, 3b, 4b), a plurality of bottom rollers (1a, 2a, 3a, 4a), a top arm (5), a saddle (1d, 2d, 3d, 4d) for each top roller (1b, 2b, 3b, 4b) and a guide element (8). The plurality of top rollers (1b, 2b, 3b, 4b) is rotatably arranged over a plurality of bottom rollers (1a, 2a, 3a, 4a). Each top roller comprises an axle (b) having axle centre portion (b’) and axle end portion (b’’). The top arm (5) is mounted on a shaft provided in the spinning machine. The saddle (1d, 2d, 3d, 4d) for each top roller (1b, 2b, 3b, 4b) is slidably mounted on said top arm (5). Each saddle comprises a top roller supporting portion (1c, 2c, 3c, 4c) for mounting the axle centre portion (b’) of said top roller (1b, 2b, 3b, 4b). A guide element (8) for each top roller (1b, 2b, 3b, 4b) is mounted fixedly on the saddle (1d, 2d, 3d, 4d). The guide element (8) has a hook like structure covering the axle and arranged at a distance from the axle in such a way that the guide element (8) maintains the axis of each top roller (1b, 2b, 3b, 4b) in perpendicular to the axis of top arm (5) and parallel to respective bottom rollers (1a, 2a, 3a, 4a) and rest of the top rollers by preventing tilting or oscillatory movements of the top rollers (1b, 2b, 3b, 4b) during and after the draft setting process and during lapping of top rollers (1b, 2b, 3b, 4b) in running conditions.
[18] In accordance with the embodiments of the present invention, two guide elements (8) having a hook like structure cover the axle (b) of the top roller (1b, 2b, 3b, 4b).
[19] In accordance with the embodiments of the present invention, the distance between the two hook like structures of the guide element (8) covering the axle (b) of the top roller (1b, 2b, 3b, 4b) varies by type of the machine, depending on the center to center distance between the two top rollers. The machine includes ring frame machine, speed frame machine, air jet spinning machine, and the like. For example, for ring frame machine, the distance between the hooks of the guide element (8) covering the axle (b) of the top roller (1b, 2b, 3b, 4b) may be 25 to 30 mm. In another example, for speed frame machine, the distance between the hooks of the guide element (8) covering the axle (b) of the top roller (1b, 2b, 3b, 4b) may be 30 to 60 mm. In still another example, for air jet spinning machine, the distance between the hooks of the guide element (8) covering the axle (b) of the top roller (1b, 2b, 3b, 4b) may be 200 to 220 mm. The horizontal gap / distance between the hook like structure of guide element (8) and the corresponding top roller side face is around 5 mm.
[20] In accordance with the embodiments of the present invention, the bottom rollers (1a, 2a, 3a, 4a) are extended across the length of the machine from one end to the other and driven either by gears or individual motors. These bottom rollers (1a, 2a, 3a, 4a) are supported over the roller stands of the machine frame with its bearings.
[21] In accordance with the embodiments of the present invention, the axle centre portion (b’) has substantially a minimum diameter than a dimeter of axle end portions (b’’). The axle centre portion (b’) of each top roller (1b, 2b, 3b, 4b) are inserted in the respective top roller supporting portions (1c, 2c, 3c, 4c).
[22] In accordance with the embodiments of the present invention, the said saddle (1d, 2d, 3d, 4d) is mounted in an adjustable manner in the axis of the top arm (5). The saddle (1d, 2d, 3d, 4d) has an inverted U-shaped cross section. The top arm (5) is mounted through the hole (6) on a shaft provided in the spinning machine. The said shaft extends throughout the length of the spinning machine. The top arm (5) is provided with a locking lever (7) which provides the locking and unlocking mechanism for the top rollers (1b, 2b, 3b, 4b) over the bottom rollers (1a, 2a, 3a, 4a) during the machine running condition.
[23] In accordance with the embodiments of the present invention, the guide element (8) preferably covers more than 50% of the circumferential portion of said axle end portions (b’’) of the top roller (1b, 2b, 3b, 4b).
[24] In accordance with the embodiments of the present invention, the thickness of the hook like structure covering the axle is in the range of 1 to 3 mm.
[25] According to an embodiment of the present invention, the guide element (8) is made from a single plate covering one or two opposite sides of the top rollers (1b, 2b, 3b, 4b). In another embodiment, the guide element (8) is made from two separate plates covering one or two opposite sides of the top rollers (1b, 2b, 3b, 4b). Further, the guide element (8) is made from a plastic or a metal or a composite material.
[26] In accordance with the embodiments of the present invention, the guide element (8) has at least two the insertion holes (9) corresponding to the fitting holes (10) of the saddle (1d, 2d, 3d, 4d) for connecting the guide element (8) by screws or bolts and nuts. The fitting holes (10) can be formed in existing saddles of the conventional drafting arrangement of spinning machines. Accordingly, by mounting the guide element (8) in the existing saddles of the drafting arrangement, the present invention can be applied to conventional drafting arrangements.
[27] In another aspect, the present invention also relates to a guide element (8) for a plurality of top rollers (1b, 2b, 3b, 4b) in textile spinning machines. The guide element (8) comprises a hook like structure covering the axle and arranged at a distance from the axle in such a way that the guide element maintains the axis of each top roller (1b, 2b, 3b, 4b) in perpendicular to the axis of top arm (5) and parallel to respective bottom rollers (1a, 2a, 3a, 4a) and rest of the top rollers by preventing tilting or oscillatory movements of the top rollers (1b, 2b, 3b, 4b) during the draft setting process and during lapping of top rollers (1b, 2b, 3b, 4b) in running conditions.
[28] In accordance with the embodiments of the present invention, by mounting the guide element (8) to the saddle (1d, 2d, 3d, 4d) of the drafting arrangement (1), the structural modifications of the supporting portion (1c, 2c, 3c, 4c) or the top arm (5) of the drafting arrangement (1) is not done. The guide element (8) effectively prevents the top rollers (1b, 2b, 3b, 4b) from oscillating or tilting during and after the draft setting process and also during the top rollers (1b, 2b, 3b, 4b) lapping due to accumulation of fibre materials on the surface of top rollers (1b, 2b, 3b, 4b). The parallelism of the top roller (1b, 2b, 3b, 4b) with respect to the bottom roller (1a, 2a, 3a, 4a) is always maintained and ensured to prevent the spindle to spindle yarn count variations and yarn imperfections between the spinning stations in the textile spinning machines. Also, the drafting setting is effectively maintained for long running time.
[29] The terms and words used in the following description are not limited to the bibliographical meanings, but, are merely used by the inventor to enable a clear and consistent understanding of the invention. Accordingly, it should be apparent to those skilled in the art that the following description of the system is for the purpose of understanding and nowhere limit the invention. The abovementioned parts nowhere limit the invention and are provided for understanding of the invention.
[30] Although there has been shown and described the preferred embodiment of the present invention, it will be readily apparent to those skilled in the art that modifications may be made thereto which do not exceed the scope of the appended claims. Therefore, the scope of the invention is only to be limited by the following claims.

LIST OF REFERENCE NUMERALS
1b, 2b, 3b, 4b a plurality of top rollers
1a, 2a, 3a, 4a a plurality of bottom rollers
B axle of top roller
b’ axle centre portion
b’’ axle end portion
1d, 2d, 3d, 4d Saddle
1c, 2c, 3c, 4c top roller supporting portion
5 top arm
6 hole
7 locking lever
8 guide element
9 insertion holes
10 fitting holes

,CLAIMS:
1. An improved drafting arrangement (1) in textile spinning machines, comprising:
a top arm (5) mounted on a shaft provided in the spinning machine;
a plurality of top rollers (1b, 2b, 3b, 4b) rotatably arranged over a plurality of bottom rollers (1a, 2a, 3a, 4a), each top roller comprises axle (b) having axle centre portion (b’) and axle end portion (b’’);
a saddle (1d, 2d, 3d, 4d) for each top roller (1b, 2b, 3b, 4b) slidably mounted on said top arm (5), each saddle comprises top roller supporting portion (1c, 2c, 3c, 4c) for mounting the axle centre portion (b’) of said top roller; and
a guide element (8) for each top roller (1b, 2b, 3b, 4b) mounted fixedly on the saddle (1d, 2d, 3d, 4d), said guide element (8) has a hook like structure covering the axle and arranged at a distance from the axle in such a way that the guide element (8) maintains the axis of each top roller (1b, 2b, 3b, 4b) in perpendicular to the axis of top arm (5) and parallel to respective bottom rollers (1a, 2a, 3a, 4a) and rest of the top rollers by preventing tilting or oscillatory movements of the top rollers (1b, 2b, 3b, 4b) during and after the draft setting process and during lapping of top rollers (1b, 2b, 3b, 4b) in running conditions.

2. The drafting arrangement (1) as claimed in claim 1, wherein said guide element (8) preferably covers more than 50% of the circumferential portion of said axle end portions (b’’) of the top roller (1b, 2b, 3b, 4b).

3. The drafting arrangement (1) as claimed in claim 1 or 2, wherein said guide element (8) is made from a single plate covering one or two opposite side of the top rollers (1b, 2b, 3b, 4b).

4. The drafting arrangement (1) as claimed in claim 1 or 2, wherein said guide element (8) is made from two separate plates covering one or two opposite side of the top rollers (1b, 2b, 3b, 4b).

5. The drafting arrangement (1) as claimed in any one of the preceding claims 1 - 4, wherein said guide element (8) is made from a plastic or a metal or a composite material.

6. The drafting arrangement (1) as claimed in any one of the preceding claims 1-5, wherein said guide element (8) has at least two insertion holes (9) corresponding to the fitting holes (10) of the saddle (1d, 2d, 3d, 4d) for connecting the guide element (8) by screws or bolts and nuts.

7. The drafting arrangement (1) as claimed in claim 1, wherein the thickness of the hook like structure covering the axle is in the range of 1 to 3 mm.

8. A guide element (8) for a plurality of top rollers (1b, 2b, 3b, 4b) in textile spinning machines, comprising a hook like structure covering the axle and arranged at a distance from the axle in such a way that the guide element maintains the axis of each top roller (1b, 2b, 3b, 4b) in perpendicular to the axis of top arm (5) and parallel to respective bottom rollers (1a, 2a, 3a, 4a) and rest of the top rollers by preventing tilting or oscillatory movements of the top rollers (1b, 2b, 3b, 4b) during and after the draft setting process and during lapping of top rollers (1b, 2b, 3b, 4b) in running conditions.