|Title of Invention||
|Abstract||Summary In a spinning frame with a number of spinning units (s) and drafting units (R), the drafting units (R) are provided with drafting roller pairs (11). From said roller pairs yarns (5.1 - 5.4') are being led to the spinning units (S), each of which comprises one spindle (30) , which is spaced towards a neighbouring spindle (30) by one spindle pitch (A). From one pressure arm (24) of a drafting unit (R ) two pressure rollers (12.1, 12.2) each are kept in contact with the drums (13.1, 13.2), whereat one pressure roller (12.1, 12.2) each is being arranged to two spinning units (S3, Si and S2, S4, respectively). The two pressure rollers (12.1, 12.2) on the pressure arm (24) are spaced at a distance (a') from each other which corresponds with 1 ^ to 2 times of the spindle pitch (A) between two spinning units (S3, Si and 82, S4 respectively) .|
|Full Text||The invention relates to a spinning frame with a number of spinning units and drafting units, wherein the drafting units are provided with drafting rollers, from each of which yarns are led to a spinning unit, each of which is provided with a spindle, which is spaced towards a neighbouring spindle by one spindle pitch and whereto by way of a pressure arm of a drafting unit,one pressure roller with two pressure surfaces-each is kept in contact with a drafting roller, wher^ifj.- one pressure surface is being provided for two spinning units.
In today's spinning frames, ring spinning frames in particular, as a rule there are evenly spaced spinning units side by side on a machine frame or alike. A roving from a creel is being drafted by the drafting unit wherein separation of the roving into roving bundles can take place.
Recently the compact spinning has been developed where the drafting rollers are of special
The lower front delivery roller is being replaced by a hollow sieve drum with larger diameter. Within said drum, by means of a suction system a certain vacuum and thus an air stream from the outside to the inside of the drum is being generated. The advantages of compact spinning and the corresponding drafting units are for instance described in Melliand, special print 3/1995, pp 119 to 123, „Compact spinning, a new generation of ring spinning yarns", an article written by Dr. Herbert Stadler or in the US-A-5 085 04 6.
Up until now the elements of the drafting units, for instance the pressure rollers, with respect to the spinning units are arranged in such a way, in that the roving in the drafting unit is being led, in a plane across to the drafting roller, to the spinning unit by the yarn itself. This arrangement, however, means that at a double occupation of the pressure rollers in the drafting units by two rovings, the second yarn has to be led to a neighbouring spinning unit at a relatively steep angle
to this plane. This angle in the past has led to considerable thread breaks.
It is the task of the present invention to develop a spinning frame according to the above described type where an improved guidance of the yarn to the spinning units is being realised.
The task is solved in that for the two pressure surfaces on the pressure arm a distance from each other is being maintained which corresponds with the 1 ^ to 2 times of the spindle pitch between two spinning units.
This means that the front roller arrangement, or the front drafting roller and its pressure surfaces are shifted in their position in relation to the spinning unit. This, of course, applies for those spinning units where at least two rovings are being led per front roller arrangement or otherwise in one front roller arrangement, one roving is being divided into two yarns. The advantage of said shift of the front roller arrangement is based on the fact, that the angle at which the yarns are led to the neighbouring spinning units is reduced. This results in an improvement of the yarn guidance and in particular a reduction of the thread breaks.
Preferably a middle plane which approximately runs vertically and centrically in relation to the pressure surface being arranged on a pressure arm of a drafting unit, should maintain the same distance towards both spinning units. At the same time the angles at which two yarns are led in relation towards the centre plane are also the same.
By shifting the front roller arrangement a considerable increase of the distance from each other of said front roller arrangement results, if there are two front roller arrangements provided per drafting unit. Up to now, for two front roller arrangements in a drafting unit a distance of approximately 70 mm were maintained. Said distance is now increased to twice the
amount, that is up to 140 mm, since the respective middle plane of the pressure surfaces between two spinning units each is being shifted.
As mentioned above the present invention is particularly practical in compact spinning. Particularly if the roving is being divided into two yarns on the sieve drum, as is disclosed in US-A5 085 046, then these yarns can be drawn from the drafting unit to the spinning units at a relatively small angle which, however, is the same for both spinning units.
By increasing the distance between two front roller arrangements for each drafting unit, the length of the shaft, which connects the two front roller arrangements also increases.
By increasing the length of said shaft, an undesirable side effect can develop, in that the pressure surfaces bend upwards. Thus they not anymore rest exactly plane on the lower roller and in particular on the sieve drum so that the quality of guidance of the roving within the front roller arrangement decreases.
In order to compensate for this disadvantage, for instance a pressure roller within the zone of the pressure place could be covered with a rubber layer or could have a rubber cone slided onto the pressure roller. This means, that towards the free end of the pressure roller, it would comprise a larger diameter than at the side which connects to the shaft.
Furthermore, it is also possible that the rubber layer is made of a material which balances to a certain extend an unlifting movement of the pressure surface from the lower roller. For instance a somewhat softer rubber cover than such having been applied up to now could be practical. However, the danger of wear of such type of rubber cover thus increases.
Accordingly the present invention provides a spinning frame with a number of spinning units and drafting units whereby the drafting units are provided with drafting rollers , from which yarns are being led to the spinning units which comprise one spindle each and which are spaced by a spindle pitch from the neighbouring spindle and whereby from a pressure arm of a drafting unit one pressure roller with two pressure surfaces each, is kept in contact with the drafting roller, whereby one pressure surface is being provided for two spinning units, characterized in that the two pressure surfaces maintain a distance from each other on the pressure arm , which corresponds with 1 'A to 2 times of a spindle pitch between two spinning units.
Further advantages, characteristics and details of the invention are disclosed in the following description of preferred exemplified embodiments and according to the drawings; wherein show;
figure 1 a schematic side view of a drafting unit for a ring spinning frame
figure 2 a schematic side view of a part of a conventional ring spinning frame with a device for compact spinning
figure 3 a schematic side view of a part of a ring spinning frame for compact spinning according to the present invention;
figure 4 a top view of two pressure rollers being connected by a shaft.
A drafting unit R for a not further shown ring spinning frame according to figure 1 is provided with a rear roller pair 1, which comprises a pressure roller 2 and a drive roller 3. The rear roller pair 1 is preceded by a roving guide 4 into which runs a roving 5 from a not further shown creel.
The roving 5 enters between the pressure roller 2 and the drive roller 3 and is led to a middle roller pair 6. Between the rear roller pair 1 and the middle roller pair 6 a pre-drafting of the roving 5 takes place, so that the zone between the two roller pairs 1 and 6 is called a pre-drafting zone W. In order that a pre-drafting can take place, the rollers of the middle roller pair 6 rotate faster than the ones of the rear roller pair 1.
The middle roller pair 6 also comprises a pressure roller 7 and a drive roller 8. Pressure roller, drive roller 8 respectively
are enclosed by a belt 9 and 10 each, and form together the belt guidance for the roving 5.
The middle roller pair 6 with the belt guidance is followed by a front roller arrangement 11, consisting of a pressure roller
12, a sieve drum 13 which functions as a drafting roller and a
further pressure roller 14. In the zone between the middle
roller pair 6 and the front roller pair 11 preferably the main
drafting takes place, therefore the zone between them is also
called the main drafting zone HV.
Figure 2 shows four sieve drums 13.1 to 13.4, which are mounted on one common shaft 15. They are fixedly connected with the shaft 15 and accordingly rotate together with the shaft 15.
An outer casing 16 of the sieve drum 13 is provided with perforations 17, which enter into a ring channel 18 which is formed with the sieve drum 13 between the outer casing 16 and a hub parting 19 resting on the rotating shaft 15. Within the ring channel 18 there is a suction element 20, which is connected to suction channel 21. In relation to the sieve drum
13, the suction element 20 and suction channel 21, are fixedly
arranged and in relation to the rotating shaft 15 they are
supported by a bearing 22. By way of the suction element 20 the
roving is being drawn onto the outer casing surface 16 of the
sieve drum, as is described for instance in US-A-5 085 046. For
that reason a further description of compact spinning is not
Figure 2 shows two conventional ways of spinning. One way shows two sieve drums 13.1, 13.2 and 13,3, 13.4 each as drafting rollers being located very close to each other. A distance „a" between the two middle planes Ei and E2 of pressure surfaces 12.1 and 12.2 being provided on a pressure arm amounts to approximately 70 mm. For this reason the two pressure surfaces 12.1 and 12.2 being assigned to the sieve drums 13.1 and 13.2
are also connected to the pressure arm 24 through relatively short shaft ends 23.
The position of the middle plane Ei and E2, which run vertically and centrically through the pressure surfaces 12.1 and 12.2, is chosen in such a way, that the two neighbouring spinning units Si and S2 lay approximately within said middle planes Ei and E2 and that also the roving 5.1, 5.2, the yarn respectively runs within these middle planes Ei and E2 after passing the drafting unit Ri. This means that two neighbouring spindles 30.1 and 30.2 are arranged at the spindle pitch A which roughly corresponds with the distance „a" between the middle planes Ei and E2.
Besides the drafting unit Ri there is shown a further, rather rarely applied yarn guidance by way of the drafting unit R2. Therefore on the sides of the spinning units Si' and S2' additional spinning units S3' and S4' are provided.
Thereby it is shown that a yarn 5.1', 5.2' each runs from a front roller pair 11.1 or 11.2 respectively within approximately the middle plane Ei and E2 to the spinning units Si' and S2'. This results in a relatively straight drawing-off of said yarns 5.1', 5.2', while the yarn 5.3' and 5.4' being led to the spinning units S3' and S4' encloses an angle w to the middle planes Ei and E2. Said angle w is relatively steep, which results increasingly in thread breaks.
Figure 3 shows on the other hand an arrangement of the sieve drums 13.1 to 13.4 according to the invention, being mounted on the rotating shaft 15. The middle planes Ei' and E2' of the pressure surfaces 12.1 and 12.2 measure a distance a' of approximately 140 mm.
Thereby the middle planes Ei' and E2' of the pressure surfaces 12.1 and 12.2 pass approximately between two spinning units S3 and Si, S2 and S4 respectively. Therefore, the two yarns 5.3'
and 5.1', 5.2' and 5.4', enclose each an angle Wi or W2, respectively with said middle planes Ei' and E2' , each of which amounts to approximately the same and which corresponds with about half of the previous angle w. For this reason a more even drawing-off of the yarns 5.1' to 5.4' is accomplished, and considerably fewer thread breaks occur. In addition it shows a drafting unit R2' that per pressure roller two rovings, fibre bands respectively, can be drawn off from the right and the left side of the pressure arm.
For a jprsi ctio»yarrangement of the pressure surfaces 12.1 and 12.2, 12.3 and 12.4 respectively on a pressure arm 24, to the corresponding neighbouring sieve drums 13.1 and 13.2, 13.3 and 13.4 respectively, of the drafting units Ri' and R2', said pressure surfaces have to be connected with a relatively long shaft 25.1 and 25.2 respectively. Said shaft 25 is especially shown in figure 4.
With such a long shaft 25 it cannot be avoided that the pressure surfaces 12.1 and 12.2 will slightly deflect in the direction of the arrow 2 6 when co-operating with the sieve drums 13.1 and 13.2. Thus the outer surface 27 of a pressure surface 12.1, 12.2 respectively, is not any more plane with the outer casing surface 16 of the sieve drum 13.1, 13.2 respectively, so that the guidance of the roving could be disturbed.
In order to balance this disadvantage two measures are possible. One measure being that each pressure surface 12.1, 12.2 respectively, could be made slightly conical as indicated by the dotted line 28.
A further possibility exists in that the pressure surfaces 12.1, 12.2 respectively are furnished with a rubber layer 29 which is considerably softer than a rubber layer being applied up to now. Thus the rubber layer 2 9 can compensate the
deflection of the pressure surfaces 12.1, 12,2 respectively, however, wear of this rubber layer might increase.
1. A spinning frame with a number of spinning units (S) and drafting units (R ) waterbed the drafting units ( R ) are provided with drafting rollers (11), from which yams (5.1' - 5.4') are being led to the spinning units (S) which comprise one spindle (30) each and which are spaced by a spindle pitch (A) from the neighbouring spindle (30) and whereby from a pressure arm (24) of a drafting unit ( R ) one pressure roller (12) with two pressure surfaces (12.1, 12.2) each, is kept in contact with the drafting roller (13.1, 13.2), whereby one pressure surface (12.1, 12.2) is being provided for two spinning units (S3, Si; S2, S4 respectively), characterized in that the two pressure surfaces (12.1, 12.2) maintain a distance (a') from each other on the pressure arm (24), which corresponds with 1 V2 to 2 times of a spindle pitch (A) between two spinning units (S3, S|; S2, S4 respectively).
2. The spinning frame as claimed in claim 1, wherein a middle plane (E|', E2') which runs centrically and vertically through the pressure surfaces (12.1, 12.2), also runs approximately through the center between each of two spinning units (S3, Si; S2, S4 respectively).
3. The spinning frame as claimed in claim 1, wherein the distance (a') of the pressure surfaces (12.1, 12.2), the middle plane (Ei', E2') respectively amounts approximately to 140 mm.
4. The spinning frame as claimed in any one of the claims 1 to 3, wherein the drafting roller is furnished as a sieve drum (13) which operates together with a suction device (20, 21).
5. The spinning frame as claimed in any one of the claims 1 to 4, wherein
the pressure surface (12.1, 12.2) is being shaped conically.
6. The spinning frame , as claimed in any one of the claims 1 ^ 5, wherein
the pressure surface (12.1, 12.2) is furnished with a relatively soft rubber layer
(29) and/or that said rubber layer (29) is being shaped as a cone.
7. A spinning frame, substantially as herein described with reference to the
|Indian Patent Application Number||604/MAS/1997|
|PG Journal Number||30/2009|
|Date of Filing||21-Mar-1997|
|Name of Patentee||MASCHINENFABRIK RIETER AG|
|Applicant Address||KLOSTERSTRASSE 20, CH-8406 WINTERTHUR|
|PCT International Classification Number||D01H05/36|
|PCT International Application Number||N/A|
|PCT International Filing date|