Title of Invention

A DEVICE FOR CONDENSING A FIBRE STRAND IN A SPINNING MACHINE.

Abstract

The invention relates to a device for condensing a fibre strand (1) in a spinning machine having a drafting unit (2), the b device comprising a front roller pair (3) which borders a drafting zone of the drafting unit (2), a condensing zone (11) being arranged downstream of a drafting zone, a driven bottom roller (7) and a pressure roller (8), an air-permeable transport belt (12) which transports the fibre strand (1) through the condensing zone (11), a suction channel (14) arranged to the condensing zone (11) for guiding the transport belt (12) on a sliding surface (13), a suction slit (16) located in the sliding surface (13), a nipping roller (19) which borders the end of the condensing zone (11) and which is pressed to the sliding surface (13), a deflecting roller (18) which tensions the transport belt (12) and comprising drive elements (27) coupled to the bottom roller (7) for the transport belt (12). The deflecting roller (18) is arranged in the area of the bottom roller (7) and forms together therewith wedge- shaped gap (29), and in that the drive elements comprise an intermediary roller (27), which is disposed in the wedge-shaped gap (29) at the bottom roller (7) and the deflecting roller (18).

Full Text

FIELD OF THE INVENTION The present invention relates to an arrangement in a spinning machine for condensing a fibre strand, comprising a front roller pair which borders the condensisng zone of a drafting unit, and which comprises a driven bottom roller and a pressure roller, comprising a condensing zone arranged downstream of the drafting zone, comprising an air-permeable transport belt which transports the fibre strand through the condensing zone, comprising a suction channel arranged to the condensing zone which suction channel guides the transport belt on a sliding surface, compprising a suction slit located in the sliding surface, comprising a nipping roller which borderl the end of the condensing zone and which is pressed to the sliding surface, comprising a deflecting roller which tensions the transport belt and also comprising drive elements coupled to the bottom roller for the transport belt. BACKGROUND OF THE INVENTION When a drafted fibre strand is imparted a spinning twist directly downstream of the front roller pair of the drafting unit, a so-called spinning triangle occurs at the nipping line of 2/ the front roller pmir. This comes about because the drafted fibre strand leaves the drafting unit having a certain width and is twisted to a thread having a relatively small diameter. The spinning triangle comprises lateral fibres, which are not properly bound into the twisted thread and thus contributes little or nothing to the tensile strength of the spun thread. In recent times, a condensing zone has been arranged downstream of the drafting zone of a drafting unit, which condensing zone is in turn bordered by a nipping line. Only downstream thereof is the thread imparted its spinning twist. The fibres are bundled or condensed in the condensing zone, whereby the fibre strand is so narrow when it leaves the nipping line furthest downstream that the feared spinning triangle does not occur. The spun thread is then more even, tear-resistant and less hairy. A device of the above mentioned type for condensing a fibre strand is prior art in Gernman published Patent Application 199 03 113. In this known device, the drive of the transport belt is derived from the bottom roller of the front roller pair via a plurality of friction stages. The pressure roller is driven by the bottom roller, against which is pressed the pressure roller is in turn connteted via a drive bait to the nipping roller which borders the condensing zone at its exit side. The nipping rollerf which presses the transport belt to the sliding surface of the suction channel, in turn drives the transport belt by means of friction. DE 19837181 Al corresponds to US 6185790 B 1 which discloses how the transport belt is driven. At the known device the transport belt is wrapped around the bottom roller of the drafting unit and, therefore, directly driven by this bottom roller. The disadvantage of the known drive is the fact that the nipping roller must be pressed with a minimum pressure to the transport belt in order to permit a friction drive, which minimum pressure is higher than would be necessary for the function of a twist block. In the combined effect with the friction of the transport belt on the sliding surface, an increased wear of the suction channel in the area of the delivery nipping line occurs. OBJECTS OF THE INVENTION It is the object of the present invention to divert the drive for the transport belt from the bottom roller of the front roller pair while maintaining the pressure of the nipping roller on the sliding surface only as high as would be necessary for a twist block. SUMMARY OF THE INVENTION This object has been achieved in accordance with the prtttnt invention in that the deflecting roller is arranged in the area of the bottom roller, the two rollers forming a wedge-shaped gapt and in that the driving elements comprise an intermediate roller, which is disposed in the wedge-shaped gap at the bottom roller and the deflecting roller. The transport belt is no longer driven at one place by means of friction at which it slides over a sliding surface, as in the above prior art, but rather is clamped at the place of its friction drive between two rotating rollers. The deflecting roller is hereby sprung against the intermediary roller. As the deflecting guide and the intermediary roller are rotating in the same direction, no significant wear occurs at the place of the drive transfer despite a sufficiently high pressing force. At the delivery nipping line, the nipping roller* which is now in turn driven by the transport belt, need only apply the pressure required for a twist block, so that at the critical place of the nipping line* the wear of the suction channel is significantly reduced. At the same time, the power requirement for the drive is also reduced. In order that the transport belt is reliably taken along the intermediary roller, the latter is provided with a suitable friction coating. It is possible that the intermediate roller is disposed only on lateral collars of the deflecting roller and that the transport belt is taken along by the looping angle at the deflecting roller, however, it is more advantageous when the transport belt is clamped between the deflecting roller and the intermediary roller at its drive point. As it is purposeful to provide the fibre strand in the condensing zone with a certain tension, the speed of the transport belt should be somewhat greater than the peripheral speed of the front roller pair. For this reason the bottom roller is provided with a collar of increased dimensions, on which the intermediary roller is disposed. The collar can be an easily replaceable disc, so that the tension can be adjusted as required. BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS These and further objects, features and advantages of the present invention will become more readily apparent from the following detailed description thereof when taken in conjunction with the accompanying drawings whereint Figure 1 is 1 part intersectional side view of the arrangement according to the prtstnt invention. Figure 2 is a view in the direction of the arrow 11 of Figure 1 of the actual condensing zone and the drive elements of the transport belt. DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT OF THE INVENTION Of a spinning machine1 in particular a ring spinning machine1 only the end area of a drafting unit 2 in connection with an arrangement for condensing a fibre strand 1 is shown. Of the drafting unit 2 itself only a front roller pair 3 as well as an apron pair 4 arranged upstream thereof and comprising a lower apron 9 and an upper apron 6 are shown. The front roller pair 3 comprises in turn a driven bottom roller 7 and a pressure roller 8, which, together with the bottom roller 7, forms a front nipping line 9. The drafting zone of the drafting unit 2 comes to an end at the front nipping line 9. In the drafting unit 2 1 sliver or raving 10 is drafted in transport direction A to the desired degree of fineness in the known way. Directly downstream of the front roller pair is a condensing zone 11, in which the draftedt but still-twist free fibre strand 1 is bundled or condensed. An air-permeable transport belt 12 is a part of the condensing zone 11, which transport belt 12 can be tbin fine- meshed woven belt made of polyamide threads. The transport belt 12 transports the fibre strand 1 to be condensed through the condensing zone 11 and is guided hereby over a stationary sliding surface 13. The sliding surface 13 is preferably the outer contour of a suction channel 141 in which a vacuum prevails1 and which extends over a plurality of spinning stations. The suction channel 14 is connected via a vacuum conduit 13 to a vacuum source (not shown). In the sliding surface 13 a suction slit 16 is located, which extends essentially in transport direction A, but slightly diagonally to the direction of motion of the transport belt 12. On its inner side in travel direction1 the suction slit 16 has a so-called gathering edge 17, along which the fibre strand 1 to be condensed travels and is hereby simultaneously rolled in. Apart from the sliding surface 13, the transport belt 12 is also guided over a deflecting roller 18, which is arranged at a distance from the suction slit 16, extends over a plurality of spinning stations and which tensions the transport belt 12. At the exit end of the condensing zone 11 a nipping roller 19 is provided, which presses the fibre strand 1 together with the transport belt 12 against the sliding surface 13 at a delivery nipping line 20, and which nipping roller 19 is driven by the transport belt 12. The delivery nipping line 20 thus borders the condensing zone 11 and acts simultaneously as a twist block for the spinning twist to be applied subsequently, which should not retroact back into the condensing zone 11. Downstream of the delivery nipping line 20, the spun thread 21 is produced, which is fed in delivery direction B to a twist device1 for example a ring spindle. A top weighting arm 22 is 1 part of the drafting unit 2 in a known way, which top weighting arm 221 in addition to the pressure roller 8 and the remaining pressure roller (not shown) of the drafting unit 2, also supports the nipping roller 19. Due to the very varying loading pressures of the pressure roller 8 and the nipping roller 191 the loading device of the top weighting arm 22 comprises a pressure spring 23 for the pressure roller 8 and a pressure spring 24 for the nipping roller 19. The force of the pressure spring 23 is many times that of the pressure spring 24. The driven bottom roller 7, as well aa the remaining bottom rollers (not shown) of the drafting unit 2 extend in the standard way in longitudinal direction of the spinning machine and arc supported in so-called roller stands 23 at suitable distances to one another; a roller stand 25 is indicated in Figure 2. These roller stands 25 also support the suction channel 14 and the deflectng roller 18. The deflecting roller 18 is arranged according to the present invention in direct proximity to the bottom roller 7 and forms a wedge-shaped gap 29 therewith. An intermediary roller 27 is located in this wedge-shaped gap 291 which intermediary roller 27 is also supported in the roller stand 25 and which is disposed resiliently against the bottom roller 7 and the deflecting roller 18. The intermdiary roller 27 is hereby driven by the bottom roller 7, which intermediary roller 27 in turn drives simultaneously1 by means of friction1 the deflecting roller 18 and the transport belt 12 . For this purpose the intermediary roller 27 is provided with a suitable friction coating 28. As can be seen in particular in Figure 1, ther1 are two moving components which rotate in the same direction at the point of the friction drive1 namely, the intermediary roller 27 and the deflecting roller 18. As a result1 there is practically no wear despite the pressing force required for the friction drive. The nipping roller 191 which in turn is now driven by the transport belt 121 need only be pressed against the sliding surface 13 in the area of the delivery nipping line 2O with the sufficient pressure to ensure the desired twist block effect. In order that the speed of the transport belt 12 for generating a slight tension on the fibre strand 1 is higher than the peripheral speed of the front roller pair 3, the bottom roller 7 is provided in the proximity of the roller stand 25 with a collar of enlarged dimensions1 which can, for example, be formed by an exchangeable disc 26. The intermediary roller 27 is thus disposed only on this disc 26 and is driven by sam,. As the disc 26 has a somewhat larger diameter in comparison to the diameter of the actual bottom roller 7, the required tension of the fibre strand 1 is ensured. WE CLAIM: 1. A device for condensing a fibre strand (1) in 1 spinning machine having a drafting unit (2), the device comprising a front roller pair (3) which borders a drafting zone of the drafting unit (2), a condensing zone (11) being arranged downstream of a drafting zone, a driven bottom roller (7) and a pressure roller (8>, an air-permeable transport belt (12) which transports the fibre strand (1) through the condensing zone (11), a suction channel (14) arranged to the condensing zone (11) for guiding the transport belt (12) on a sliding surface (13), a suction slit (16) located in the sliding surface (13)1 a nipping roller (19) which borders the end of the condensing zone (11) and which is pressed to the sliding surface (13), a deflecting roller (18) which tensions the transport belt (12) and comprising drive elements (27) coupled to the bottom roller (7) for the transport belt (12), characterized in that the deflecting roller (18) is arranged in the area of the bottom roller (7) and forms together therewith wedge-shaped gap (29), and in that the drive elements comprise an intermediary roller (27), which is disposed in the wedge-shaped gap (29) at the bottom roller (7) and the deflecting roller (18). 2. The device «s claimed in claim l, wherein the intermediary roller (27) is provided with a friction coating (28). 3. The device as claimed in claiom 1 or 21 wherein the transport belt (12) is clamped between the deflecting roller (18) and the intermediary roller (27). 4. The device as claimed in any of the claims 1 to 31 wherein the bottom roller (7) is provided with a collar (26) of enlarged dimensions1 on which the intermediary roller (27) is disposed. 9. The device as claimed in claim 4, wherein the collar comprises an exchangeable disc (26). The invention relates to a device for condensing a fibre strand (1) in a spinning machine having a drafting unit (2), the b device comprising a front roller pair (3) which borders a drafting zone of the drafting unit (2), a condensing zone (11) being arranged downstream of a drafting zone, a driven bottom roller (7) and a pressure roller (8), an air-permeable transport belt (12) which transports the fibre strand (1) through the condensing zone (11), a suction channel (14) arranged to the condensing zone (11) for guiding the transport belt (12) on a sliding surface (13), a suction slit (16) located in the sliding surface (13), a nipping roller (19) which borders the end of the condensing zone (11) and which is pressed to the sliding surface (13), a deflecting roller (18) which tensions the transport belt (12) and comprising drive elements (27) coupled to the bottom roller (7) for the transport belt (12). The deflecting roller (18) is arranged in the area of the bottom roller (7) and forms together therewith wedge- shaped gap (29), and in that the drive elements comprise an intermediary roller (27), which is disposed in the wedge-shaped gap (29) at the bottom roller (7) and the deflecting roller (18).

Documents:

in-pct-2002-625-kol-granted-abstract.pdf

in-pct-2002-625-kol-granted-assignment.pdf

in-pct-2002-625-kol-granted-correspondence.pdf

in-pct-2002-625-kol-granted-description (complete).pdf

in-pct-2002-625-kol-granted-drawings.pdf

in-pct-2002-625-kol-granted-examination report.pdf

in-pct-2002-625-kol-granted-form 1.pdf

in-pct-2002-625-kol-granted-form 18.pdf

in-pct-2002-625-kol-granted-form 2.pdf

in-pct-2002-625-kol-granted-form 26.pdf

in-pct-2002-625-kol-granted-form 3.pdf

in-pct-2002-625-kol-granted-form 5.pdf

in-pct-2002-625-kol-granted-reply to examination report.pdf

in-pct-2002-625-kol-granted-specification.pdf

in-pct-2002-625-kol-granted-translated copy of priority document.pdf