Title of Invention

ANTI-TWIST DEVICE

Abstract

The invention relates to a twist stop device for guiding a thready with a twist roller and a shaft which has a holding end with a rotationally fixed connection to the twist stop roller and a bearing end for mounting. The twist stop roller is preferably formed by two ceramic discs with axially overlapping webs so as to form a zigzag-shaped thread running track. In order, on the one hand, to achieve a long service life of the mounting of the twist stop roller and, on the other hand, to ensure a customary exchangeability for wearing parts, according to the invention the bearing end of the shaft is mounted rotatably within a bearing bush, and the bearing bush, together with the mounted shaft and twist stop roller, is releasably connected as a structural unit to a roller carrier.

Full Text

Anti-Twist Device The invention relates to a twist stop device for guiding a thread according to the precharacterizing clause of Claim 1. In the production of textured yarns on the false-twist principle, it is known that a false twist is generated on a multi-filament thread by friction and is propagated in the thread opposite to the thread running direction, so that the twisted thread can be heated and fixed in what is known as a false-twist zone. In order to avoid an uncontrolled run-back of the false twist in the thread, twist stop devices are used, which have, for each thread, a twist stop roller with a zigzag-shaped thread running track formed on the circumference. A twist stop device of this type is known, for example, from DE 1 158 422. In the known twist stop device, the twist stop roller is formed from two discs which are located opposite one another so as to overlap with axially projecting webs, so that a zigzag-shaped thread running track is formed between the two discs. The discs are connected fixedly in terms of rotation to a shaft via a holding bush. To operate the twist stop device, the rotatably mounted shaft may be driven or be designed to be freely rotatably. Particularly to avoid a run-back of the false twist in the thread, the twist stop device is used with a non-driven twist stop roller. In this case, the twist stop roller is moved solely by the running thread. In order, on the one hand, to limit the false twist in the thread, a minimum looping of the thread around the twist stop roller is required. On the other hand, any thread friction acting in the thread leads to mechanical load which, particularly in the case of fine threads, may result in filament breaks. To that extent, preferably, twist stop rollers of relatively small diameter are used, in order to have a relatively short friction zone in spite of a high degree of looping. However, the disadvantage of the twist stop rollers designed with a relatively small diameter is that very high rotational speeds occur in the case of thread running speeds of up to 1500 m/min. To that extent, corresponding mountings of the twist stop rollers or of the shafts have to be provided. EP 0 460 799 Al discloses a twist stop device, in which the twist stop roller is rotatably mounted directly at the end of a shaft. A mounting of this type is highly unfavourable in the case of twist stop rollers of relatively small diameter, since only very small mountings having a limited service life can be considered. The twist stop device known from US 6,408,608 Bl likewise has a twist stop roller mounted directly at a shaft end, thus leading to the known disadvantages. The object of the invention, then, is to design a twist stop device of the generic type with a mounting of the twist stop roller which, on the one hand, affords corresponding long service lives at high rotational speeds and, on the other hand, in the event of wear, allows a rapid exchangeability of the mounting without the twist stop roller. This object is achieved, according to the invention, by means of a twist stop device, in that the bearing end of the shaft is mounted rotatably within a bearing bush, and in that the bearing bush, together with the mounted shaft and twist stop roller, can be releasably connected as a structural unit to a roller carrier. Advantageous developments of the invention are defined by the features and feature combinations of the respective subclaims. The invention has the particular advantage that the dimensions of the bearing bush for receiving the mounting of the shaft can be selected independently of the size of the twist stop roller. On the other hand, the rolling bodies required for mounting the shaft can consequently be arranged directly between the bearing bush and the circumference of the shaft. Moreover, the twist stop device can advantageously be held as a unit in a roller carrier via the bearing bush. In this case, it is particularly advantageous if the bearing bush has a cylindrical fitting casing which can be inserted, essentially free of play, into a reception orifice of the roller carrier and can be held therein. A simple rapid exchangeability of the entire twist stop device is consequently possible. Should the twist stop roller used for thread guidance have inadmissible wear phenomena, the development of the invention is particularly advantageous in which the ceramic discs are held on the circumference of a holding bush and the holding bush is connected releasably to the holding end of the shaft. Even a change of the twist stop roller can consequently be carried out, without the twist stop device having to be demounted from a roller carrier. The fastening of the holding bush to the shaft end of the shaft can in this case be carried out preferably via an inwardly projecting clamping collar which is braced directly with the end face of the shaft end via a clamping means. The clamping means used in this case may be a screw, and, to fix the shaft, the latter preferably has, on the end face of the opposite bearing end, a tool receptacle in which a holding tool can be inserted. In order, after a thread break or in the case of an incorrect piecing of a thread, to prevent the thread from being wrapped around the shaft, in addition to the twist stop roller, the development of the invention is preferably used in which the ceramic disc facing the bearing end of the shaft is assigned an outer supporting disc which has a peripheral axially projecting protective collar extending with a free end as far as the bearing bush. It is consequently not possible for a thread to fall in onto the rotating shaft. The ceramic disc facing away from the bearing end of the shaft is preferably protected against damage by an outer protective disc which is designed to project radially with a protective edge in relation to the ceramic disc. Consequently, in particular, damage during piecing caused by a manually guided suction gun can be avoided. In order to protect the mounting of the shaft within the bearing bush, the bearing bush is preferably closed on each of the end faces by means of a cover. The invention, then, is explained in more detail by means of an exemplary embodiment, with reference to the accompanying figures in which: Fig. 1 illustrates diagrammatically a cross-sectional view of an exemplary embodiment of the twist stop device according to the invention. Fig. 2 shows diagrammatically a side view of the exemplary embodiment from Fig. 1. Fig. 1 illustrates diagrammatically an exemplary embodiment of the twist stop device according to the invention in a cross-sectional view. Fig. 2 in this case shows a side view of the exemplary embodiment. In so far as no express reference to one of the figures is made, the following description applies equally to both figures. The twist stop device has a shaft 2. The shaft 2 projects with a bearing end 2.2 into a bearing bush 5. Within the bearing bush 5, a plurality of rolling bodies 6 are arranged between the circumference of the shaft 2 and the bearing bush 5. The bearing bush 5 has on each of its end faces a cover 18.1 and 18.2. The cover 18.2 is of annular design and extends between the inside diameter of the bearing bush 5 and the circumference of the shaft 2. The shaft 2 projects outside the bearing bush 5 with a holding end 2.1. The twist stop roller 1 is held on the circumference of the shaft 2 at the holding end 2.1. For this purpose, the twist stop roller 1 has two ceramic discs 3.1 and 3.2. The ceramic discs 3.1 and 3.2, on one side, possess, distributed over the circumference, a plurality of webs 4 which are held so as to overlap with one another. A thread running track 19 is formed between the ceramic discs 3.1 and 3.2, the thread being guided in a zigzag-shaped manner through the webs 4 in the looping-around region of the twist stop roller 1. The ceramic discs 3.1 and 3.2 are held on the circumference of a holding bush 10 via a centring receptacle. The holding bush 10 is of pot-shaped design and has an inwardly projecting clamping collar 11, The pot-shaped holding bush 10 is plugged onto the bearing end 2.2 of the shaft 2. To fix the holding bush 10 and the ceramic discs 3,1 and 3.2 arranged on the circumference of the holding bush 10, a clamping means 12 in the form of a screw is provided, which can be screwed on the end face into the holding end 2.1 of the shaft 2 and in this case braces the clamping collar 11 of the holding bush 10 with the holding end 2.1 of the shaft 2. On the side facing towards the bearing end 2.2, the twist stop roller 1 has a supporting disc 14 which is connected fixedly to the ceramic disc 3.2. The supporting disc 14 has an axially projecting protective collar 15 which with its free end partially overlaps the bearing bush 5 in the axial direction. On the side facing away from the bearing end 2.2, the twist stop roller 1 has a protective disc 16 which is fixedly connected to the ceramic disc 3.1. The protective disc 16 extends with a protective edge 17 beyond the circumference of the ceramic disc 3.1 in the radial direction and thus constitutes edge protection for the ceramic disc 3.1. The protective disc 16 and the ceramic disc 3.1 have, on the circumference, a cutout 21 which extends as far as a groove bottom of the ceramic discs 3.1 and 3.2, as illustrated in Fig. 2. The cutout 21 serves for the introduction of an auxiliary tool, in order, for example, to remove a thread wrapping from the twist stop roller 1. The protective disc 14 on one side of the twist stop roller 1 and the protective disc 16 on the opposite side of the twist stop roller 1 are connected to one another and fixed to the ceramic discs 3.1 and 3.2 by means of a plurality of screws 20. As illustrated in Fig. 1, the twist stop device is held on a roller carrier 7. For this purpose, the twist stop device is designed as a structural unit and is held in a reception orifice 8 of the roller carrier 7 via the bearing bush 5. For this purpose, the bearing bush 5 has a fitting casing 9 which can be inserted, free of play, in the reception orifice 8. The entire twist stop device can thus be connected to the roller carrier 7 by the bearing bush 5 being inserted into the reception orifice 8 or being pulled out from the latter. The roller carrier 7 is in this case preferably integrated fixedly in a machine stand. During operation, a running thread is guided in the thread running track 19 so as to loop partially around the twist stop roller 1. In this case, the twist stop roller 1 is driven via the thread, so that the shaft 2 rotates together with the twist stop roller 1. For mounting the shaft 2, preferably, balls are used as rolling bodies 6 in the bearing bush 5, in order as far as possible to obtain a low-friction mounting. Should the twist stop roller 1 have to be exchanged independently of the bearing bush 5, a demounting of the clamping means 12 from the holding end 2.1 of the shaft 2 is possible, the shaft 2 having a tool receptacle 13 on the end face of the bearing end 2.2. For this purpose, the cover 18.1 contains, on the end face of the bearing bush 5, an orifice through which a holding tool can be introduced into the tool receptacle 13. Thus, by means of the holding tool, the shaft 2 can be fixed in its position, so that the clamping means 12 can be demounted. After the mounting of the clamping means 12, the holding bush 10 can be drawn off from the holding end 2.1 of the shaft 2. The twist stop device according to the invention is particularly suitable for limiting the run-back of a false twist in the thread in a false-twist texturing machine. Since thread-guiding parts are usually wearing parts in a false-twist texturing machine, the twist stop device according to the invention is particularly suitable for making it possible to carry out a flexible and rapid change in the event of wear of the mounting or of the ceramic discs. List of reference symbols 1 Twist stop roller 2 Shaft 2 .1 Holding end 2.2 Bearing end 3.1, 3.2 Ceramic discs 4 Webs 5 Bearing bush 6 Rolling body 7 Roller carrier 8 Reception orifice 9 Fitting casing 10 Holding bush 11 Clamping collar 12 Clamping means 13 Tool receptacle 14 Supporting disc 15 Protective collar 16 Protective disc 17 Protective edge 18.1, 18.2 Cover 19 Thread running track 20 Screw 21 Cutout Patent Claims 1. Twist stop device for guiding a thread, with a twist stop roller (1) and a shaft (2) which has a holding end (2.1) with a rotationally fixed connection to the twist stop roller (1) and a bearing end (2.2) for mounting, the twist stop roller (1) being formed by two ceramic discs (3.1, 3,2) with axially overlapping webs (4) so as to form a zigzag-shaped thread running track (19), characterized in that the bearing end (2.2) of the shaft (2) is mounted rotatably within a bearing bush (5), and in that the bearing bush (5), together with the mounted shaft (2) and twist stop roller (1) , can be releasably connected as a structural unit to a roller carrier (7). 2. Device according to Claim 1, characterized in that the bearing bush (5) has a cylindrical fitting casing (9) which can be held, substantially free of play, in a reception orifice (8) of the roller carrier (7). 3. Device according to Claims 1 and 2, characterized in that the ceramic discs (3.1, 3.2) are held on the circumference of a holding bush (10) , and in that the holding bush (10) is connected releasably to the holding end (2.1) of the shaft (2). 4. Device according to Claim 3, characterized in that the holding bush (10) has a clamping collar (11) which projects inwards on one side and which can be braced by a clamping means (12) with the end face of the holding end (2.1) of the shaft (2). 5. Device according to Claim 3 or 4, characterized in that the clamping means (12) is a screw, the shaft (2) having, on the end face of the bearing end (2.2), a tool receptacle (13) in which a holding tool can be inserted for fixing the shaft (2). 6. Device according to one of Claims 1 to 5, characterized in that the ceramic disc (3.2) facing the bearing end (2.2) of the shaft (2) is assigned an outer supporting disc (14) which has a peripheral axially projecting protective collar (15) extending with a free end as far as the bearing bush (5). 7. Device according to one of Claims 1 to 6, characterized in that the ceramic disc (3.1) facing away from the bearing end (2.2) of the shaft (2) is assigned an outer protective disc (16) which projects radially with a protective edge (17) in relation to the ceramic disc (3.1). 8. Device according to one of Claims 1 to 7, characterized in that the bearing bush (5) has on each end face in each case a cover (18.1, 18.2).

Documents:

394-CHENP-2008 AMENDED CLAIMS 09-03-2012.pdf

394-CHENP-2008 CORRESPONDENCE OTHERS 19-12-2011.pdf

394-CHENP-2008 FORM-3 09-03-2012.pdf

394-CHENP-2008 OTHER PATENT DOCUMENT 09-03-2012.pdf

394-CHENP-2008 EXAMINATION REPORT REPLY RECEIVED 09-03-2012.pdf

394-CHENP-2008 POWER OF ATTORNEY 09-03-2012.pdf

394-chenp-2008-abstract.pdf

394-chenp-2008-claims.pdf

394-chenp-2008-correspondnece-others.pdf

394-chenp-2008-description(complete).pdf

394-chenp-2008-drawings.pdf

394-chenp-2008-form 1.pdf

394-chenp-2008-form 18.pdf

394-chenp-2008-form 3.pdf

394-chenp-2008-form 5.pdf

394-chenp-2008-pct.pdf