JP2006002331A - Double apron type draft device for fine spinning machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a double apron type draft device for fine spinning machine with wedge shaped clearance region not to be impaired from any members acting as obstacles. <P>SOLUTION: The invention relates to the double apron type draft device comprising a delivery nip line, a delivery roller pair containing a driven delivery roller and a press roller flexibly pressed to the delivery roller, an apron pair forming a wedge shaped clearance with staple sliver guided by the apron pair in the delivery nip line region installed on the front step, and a cover wrapping peripheral surface of the delivery roller in the apron pair region and forming a thin clearance with the peripheral surface, wherein a cover 18 is installed outside the wedge shaped clearance 15, and the clearance 17 is connected to a suction port 19 of a negative pressure pipe passage 20, and the cover 18 and the suction port 19 are set as slightly separable from the delivery roller 11 in pause time of the fine spinning process. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a double apron draft device for a spinning machine, which includes a delivery roller pair having a delivery nip line and including a driven delivery roller and a pressure roller that is elastically pressed against the driven delivery roller. An apron pair that guides the staple sliver in the area of the delivery nip line and forms a wedge-shaped gap therewith, and a cover that wraps the peripheral surface of the delivery roller in the area of the apron pair and forms a narrow gap with the peripheral surface It relates to things with.

  In the double apron type drafting device, especially when they are used in a so-called air jet spinning process, the delivery speed may be reached such that the air flow cannot be ignored as a result of the rotation of the delivery roller pair. Due to its high peripheral speed, the rotating delivery roller carries air. This is particularly true for the driven bottom roller with ribs, the so-called delivery roller, of the delivery roller pair. The air flow in the circumferential direction of the delivery roller is interrupted at the delivery nip line. Air is continuously fed into the wedge-shaped gap between the apron pair and the delivery nip line. This air flows away from the wedge-shaped gap on the one hand on both sides in the axial direction, but on the other hand, part also flows in the opposite direction to the transport direction of the staple sliver. At that time, air vortexing and fiber flow disturbance occur. This air flow causes the fibers of the staple sliver to advance from the apron pair and run to the delivery nip line more or less chaotic. This manifests itself, for example, in the degradation of the yarn quality value which increases exponentially with the delivery speed.

Attempts have already been made to totally block the air flow that circulates with the delivery roller pair. For example, Patent Document 1 discloses that at least the delivery roller is covered over most of the peripheral surface while leaving a narrow gap. This measure can certainly avoid undesirable airflow, but there is a risk that the fibers get entangled in the gap between the peripheral surface of the delivery roller and the cover and somehow leave the staple sliver and reach the gap. Furthermore, the known double apron draft device has the disadvantage that the cover protrudes into the wedge-shaped gap region between the apron pair and the delivery nip line. The apron pair must therefore have an extended distance from the delivery nip line, but this extended distance impairs the guidance of the sliver that is already very thin and not yet twisted at this point.
German Patent Application No. 4003019

  The problem of the present invention is that in a double apron draft device of the kind pointed out at the outset, an undesirable air flow is kept away from the delivery nip line area without damaging the wedge-shaped gap area by any obstructing member, and additionally in the gap. Is to remove these fiber deposits from time to time as long as it is unavoidable.

  This problem is solved by the fact that the cover is placed outside the wedge-shaped gap, the gap is connected to the suction port of the negative pressure line, and the cover and suction port can be slightly separated from the delivery roller when the spinning process is interrupted. Is done.

  By arranging the cover only outside the wedge-shaped gap, the fiber guide is not impaired in the dangerous wedge-shaped gap area between the apron pair and the delivery nip line. Furthermore, by performing a constant suction of the gap, scattering in this region is greatly avoided. However, it is not possible to completely prevent the fibers from being pinched between the cover and the delivery roller in the gap in spite of the efficient suction. Furthermore, when the spinning process is interrupted, for example, after the yarn breaks, the cover and the suction port are connected to the delivery roller. It is possible to move away slightly. In so doing, the suction port should be separated from the delivery roller only to the extent that negative pressure is still effective there. In some cases, the sandwiched fibers are freed by this separation and can reach the suction port.

  It has been found that the suction port is preferably 1 to 5 millimeters from the peripheral surface of the delivery roller, that is, it is preferable that the pinched fibers are free but can be separated so that negative pressure still works. In this case, the cover and the suction port preferably form a structural unit, so that they can be moved away from the delivery roller together. This simplifies the motion mechanism.

  In one embodiment, a rocking shaft is attached to the structural unit, and this rocking shaft is in the area of the delivery roller. In another embodiment, a linear motion guide can be attached to the structural unit.

  In another configuration of the invention, a tension strip that acts against the spring means can be attached to the structural unit, which is advantageously connected to a pneumatic operating mechanism.

Other advantages and features of the present invention will become apparent from the following description of several embodiments.
BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side view, partly in cross section, of a double apron draft device according to the present invention having a swingable and separable structural unit including a cover and a suction port.
FIG. 2 shows a double apron draft device having a structural unit formed in another mode that can be moved away from the delivery roller by a linear motion guide.

  The apparatus shown in FIG. 1 of the spinning machine serves to manufacture the spinning yarn 1 from the staple sliver 2. This device includes a double apron draft device 3 and an air jet assembly 4 as main components. The staple sliver 2 to be finely spun is supplied from the supply direction A to the double apron draft device 3, taken up in the take-up direction B as the fine spinning yarn 1, and transferred to a winding mechanism (not shown).

  The double apron draft device 3 is mainly a three-wire draft device and includes a total of three roller pairs. Each roller pair includes a driven bottom roller and a pressure roller that is elastically pressed against the driven bottom roller. . The apron roller pairs 7 and 8 following the feed roller pair 5 and 6 are provided with guide aprons 9 and 10 which are hereinafter referred to as apron pairs, followed by delivery roller pairs 11 and 12. Reference numerals 5, 7, and 11 are driven bottom rollers, and reference numerals 6, 8, and 12 are attached pressure rollers. The driven bottom roller 11 of the delivery roller pair 11, 12 is hereinafter referred to as delivery roller 11.

  In such a double apron draft device 3, the staple sliver 2 is drafted to a required fineness as is well known. Following the double apron draft device 3 is the next thin sliver 13, which is stretched but not yet twisted.

  The air jet assembly 4 that continues to the double apron drafting device 3 for a short distance and imparts the spinning twist can be of basically any construction type in the present invention, but here it is mainly special Mention is made of a structural mode that allows a high delivery rate. The delivery speed can be in the range of 300-600 meters per minute. In doing so, it is clear that extremely severe conditions are required for the double apron draft device 3 because the delivery roller pair 11, 12 must operate very quickly because of the high drafting capability.

  The delivery roller pair 11, 12 defines a delivery nip line 14, and the draft of the staple sliver 2 to be drawn ends at this delivery nip line. In this regard, it has been found that it is preferable for the yarn quality that the apron pairs 9, 10 are brought as close to the delivery nip line 14 as possible. Therefore, the path of the staple sliver 2 from the outlets of the apron pairs 9 and 10 to the delivery nip line 14 can be remarkably shortened, and the staple sliver 2 becomes unguided before the delivery nip line 14. Is only on a very short path. This is crucial for yarn quality.

  As already mentioned at the beginning, the air flow that circulates with the delivery roller pair 11, 12 is interrupted at the delivery nip line 14 and causes air vortexing, which disrupts the flow of the staple sliver 2 in this dangerous area. It is extremely troublesome. Exactly the wedge-shaped gap 15 between the apron pairs 9, 10 and the delivery nip line 14 is of special danger. This is because here the staple sliver 2 has already been drafted into a very thin sliver. In any case, in the region of the wedge-shaped gap 15, the air flow rotating together with the delivery roller pair 11, 12 now flows sideways away, causing the staple sliver 2 to flow sideways or move in the direction opposite to the feeding direction A. Must be prevented.

  By the way, in order to prevent the apron pair 9, 10 from excessively approaching the delivery nip line 14 and, on the other hand, to prevent undesirable air vortexing, the region of the apron pair 9, 10, but the wedge-shaped gap 15 A cover 18 that wraps around the peripheral surface 16 of the delivery roller 11 and forms a narrow gap 17 with the peripheral surface 16 is attached to the outer side of the delivery roller 11, and this cover must keep the circulating air flow away from the area of the delivery nip line 14. . The cover 18 has a very narrow gap 17 that acts as a diaphragm resistance, and this gap is mainly less than 0.2 mm. In addition, the gap 17 is connected to the suction port 19 of the negative pressure line 20, and the induced draft acts in the C direction. Such a suction, on the one hand, assists in the destruction of the undesired air flow boundary layer, and on the other hand allows the waste fibers supplied to the delivery nip line 14 to be sucked more than enough, for example by air flow.

  As will become apparent, the suction port 19 is mounted slightly away from the apron pair 9, 10 so that the troublesome area of the wedge-shaped gap 15 is not disturbed by the suction.

  Although the gap 17 is constantly sucked, it is inevitable that the fibers are sometimes entangled there. For this reason, when the spinning process is interrupted, for example, after yarn breakage, both the cover 18 and the suction port 19 are moved away from the peripheral surface 16 of the delivery roller 11 by about 1 to 5 millimeters. As a result, the fibers that are pinched in some cases become free and can reach the suction port 19.

  As can be seen, the cover 18 and the suction port 19 form one structural unit 18, 19 and can therefore be moved away from the delivery roller 11 together. The swing shaft 21 attached to the structural units 18 and 19 is in the area of the delivery roller 11. Therefore, the structural units 18 and 19 can slightly swing away from the peripheral surface 16 of the delivery roller 11 in the swing direction D, but contact the stopper 22 under the pressure of the spring means 24 during operation.

  A tension strip 23 acting against the spring means 24 is attached to the structural units 18, 19, which itself is mainly connected to a pneumatic operating mechanism 28. The tension band member 23 is guided through the guide rollers 25, 26, and 27 and can be loaded in the tension direction E.

  In another embodiment according to FIG. 2, the conventional symbols are maintained as long as the members have the same function. Therefore, the re-explanation is omitted here.

  The embodiment according to FIG. 2 differs from the embodiment according to FIG. 1 in that substantially linear guides 29, 30 are now provided for the structural units 18, 19 instead of rocking movements. The direction of movement of the linear motion guides 29 and 30 is denoted by F, and can also be performed against the spring means 24 by the tension band 23. The operating state is again secured by a stop 22.

  Because of the linear motion guides 29 and 30, it is possible to suck other areas of the double apron draft device 3 during operation. The other two suction ports 31 and 32 are already provided along with the suction port 19 attached to the present invention, and the suction port 31 sucks the bottom apron 9 during operation, and the suction port 32 is the bottom feed roller during operation. Aspirate 5

It is a side view which shows the double apron type draft device concerning the present invention provided with the structure unit which can be rocked and separated including a cover and a suction mouth in partial sectional view. The double apron type draft device provided with the structural unit formed in another mode which can be separated from a delivery roller by a linear guide is shown.

Claims (7)

  A double apron draft device for a spinning machine, including a delivery roller pair having a delivery nip line and including a driven delivery roller and a pressure roller elastically pressed against the delivery roller, and a delivery roller provided in a preceding stage An apron pair that guides the staple sliver in the nip line area and forms a wedge-shaped gap therewith, and a cover that encloses the peripheral surface of the delivery roller in the apron pair area and forms a narrow gap with the peripheral surface. The cover (18) is arranged outside the wedge-shaped gap (15), and the gap (17) is connected to the suction port (19) of the negative pressure line (20). ) And the suction port (19) can be slightly moved away from the delivery roller (11).   The double apron draft device according to claim 1, characterized in that the suction port (19) can move 1-5 mm away from the peripheral surface (16) of the delivery roller (11). 3. Double according to claim 1 or 2, characterized in that the cover (18) and the suction port (19) form one structural unit (18, 19) and can be moved away from the delivery roller (11) together. Apron draft device.   4. Double apron draft device according to claim 3, characterized in that a pivot shaft (21) is attached to the structural unit (18, 19) and this pivot shaft is in the area of the delivery roller (11).   The double apron draft device according to claim 3, characterized in that a linear motion guide (29, 30) is attached to the structural unit (18, 19).   Double apron according to any one of claims 3 to 5, characterized in that a tension strip (23) acting against the spring means (24) is attached to the structural unit (18, 19). Type draft device.   The double apron draft device according to claim 6, characterized in that the pneumatic operating mechanism (28) is attached to the tension strip (23).

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