GB2115018A - High draft apparatus for worsted spinning process - Google Patents

Abstract

At the gilling or bobinoir step of the worsted spinning process, a porcupine roller (102) and a middle roller system (104) are disposed between a front roller (101) and a back roller (105) to prevent unevenness occurring and to obtain a uniform sliver. The middle roller system (104) can comprise upper and lower aprons (104a, 104b), or the upper apron can be replaced by balloon rollers. The lower apron (104b) is driven by the foremost supporting roller (106). <IMAGE>

Description

SPECIFICATION High draft apparatus for worsted spinning process This invention relates to a high draft apparatus for use at the gilling or bobinoir stage generally used in the worsted spinning process.

Background of the Invention As shown in Figs. 1 and 2, in the conventional gill C and bobinoir D, a sliver 12 is controlled by needles 1 Oa of a follower 10 or by needles 1 a of a porcupine roller 11 respectively, to impart a draft to the sliver 1 2.

In one recently developed drafting apparatus in which high drafting is made possible while increasing the drafting speed, either, as shown in Fig. 3, an intermediate roller system 13 comprising balloon rollers 1 3a and a lower apron 1 3b is provided, or, as shown in Fig. 4, an intermediate roller system 14 comprising double aprons 1 4a and 1 4b is provided as a substitute for the follower or for the porcupine roller. These high drafting operations are performed without using needles, whereby the draft ratio and drafting speed can be increased.

However, such high draft apparatus is defective in the following respects as compared with the type of draft apparatus comprising a follower or a porcupine roller.

(1 ) The evenness of the sliver is poor and yarn breakages occur readily in a spinning frame.

(2) Defects in the sliver caused in the preceding steps are not substantially eliminated but, on the contrary, are sometimes made worse.

(3) The occurrence of unevenness by joining of slivers is not prevented at all.

Each of the recently developed high draft apparatuses is of an apron type or similar type as shown in Figs. 3 or 4, and it is an indispensable requirement that an ideal and good sliver should be supplied. However, incorporation of a defective sliver or a sliver having defects cannot be avoided in practice, and the above-mentioned defects (1) and (2) still occur in practical use. When such defective sliver is supplied, abnormal expansion of the sliver is more prominent than in the conventional low draft apparatus, and yarn breakages are frequently caused in a spinning frame, resulting in reduction of the yarn quality.

The defect (3) will now be described. As shown in Fig. 5, before a sliver 1 2 supplied from a can 1 5 is completely consumed, the starting end 21 2a of a sliver 212 taken out from a full can 215 which is standing by for the subsequent supply is partially lapped on to the tail end 1 2a of the sliver 12 of the can 1 5 and joining is performed. Since needles are not used in the conventional high draft apparatus as pointed out hereinbefore, the formed joint is not normally drafted but a defect of unevenness appears at the joint, and this uneven portion should be removed afterwards. Because of this operation ioss, the effects of increasing the operational speed and the productivity cannot satisfactorily be attained, and this disadvantage is especially serious when an automatic doffing apparatus is used.

Unevenness of sliver of this type cannot be checked by the naked eye and the sliver is forwarded directly to a spinning frame. Only when an uneven yarn is spun and a fabric is formed by knitting or weaving is this defect first discovered and the poor quality becomes a problem. One of the reasons why there has been hesitation over the adoption of a high draft bobinoir is a risk of this poor quality.

It is an object of the present invention to provide a high draft apparatus in which a uniform sliver can be formed by high drafting and the occurrence of unevenness is prevented when slivers are joined.

In accordance with the present invention there is provided a high draft apparatus for use in a worsted spinning process wherein, between a front roller and a back roller at the gilling or bobinoir step of the worsted spinning process, a porcupine roller is provided in advance of the front roller and an intermediate roller system is provided to follow the back roller in a series arrangement.

In the present invention both needles and aprons are used for drafting slivers so that the merits of both the needles and aprons are utilised while their disadvantages are eliminated. More specifically, according to a preferred embodiment of the present invention, there is provided a draft apparatus in which massive migration of fibres at the operation of joining slivers is controlled by the action of the needles and, simultaneously, an apron of the intermediate roller system is driven and rotated by the foremost apron-supporting roller in such a manner as if the aprons are moved to draw in the sliver, whereby the action of holding and delivering a sliver by the aprons can be performed very smoothly and the drafting operation can be accomplished precisely with certainty, with the result that the evenness of the sliver can be improved and a sliver free of unevenness due to joining can be obtained.

In the drawings: Figs. 1 to 5 are schematic side views showing conventional forms of draft apparatus.

Fig. 1 shows a gill comprising a follower; Fig. 2 shows a bobinoir comprising a porcupine roller; Fig. 3 shows a high draft bobinoir comprising balloon rollers and an apron; Fig. 4 shows a high draft bobinoir comprising double aprons; Fig. 5 illustrates the operation of joining slivers in the high draft bobinoir shown in Fig. 4.

Fig. 6 is a schematic side view illustrating a first embodiment of high draft apparatus according to the present invention.

Fig. 7 is a schematic side view illustrating a second embodiment of high draft apparatus according to the present invention.

The structure of the apparatus of the present invention will now be described in detail with reference to the embodiments illustrated in Figs. 6 and 7 of the accompanying drawings.

Figs. 6 and 7 show two embodiments of draft apparatus of the present invention. Reference numerals 1, 101 and 5, 105 represent a front roller and a back roller, respectively. In the draft apparatus A shown in Fig. 6, a porcupine roller 2 and an intermediate roller system 3 comprising balloon rollers 3a and an apron 3b are arranged in this order between the front and back rollers 1 and 5. In the draft apparatus B shown in Fig. 7, an intermediate roller system 104 comprising upper and lower double aprons 1 04a and 1 04b is provided instead of the intermediate roller system 3 comprising the balloon rollers 3a and the apron 3b of the apparatus A.The lower apron 3b or 1 04b is driven and rotated by the foremost roller 6 or 106 of a plurality of rollers supporting the apron 3b of 104b, that is, the roller 6 or 1 06 closest to the porcupine roller 2 or 102. For this purpose, a sawtooth-like shape is given to the surface of the roller 6 or 106, or the surface of the roller 6 or 106 is roughened, and the apron 3b or 1 04b is positively driven and rotated by the frictional force.

In the intermediate roller system comprising the apron and balloon rollers or the intermediate roller system comprising the double aprons, the lower apron 3b or 104b is taken out and driven by the foremost roller 6 or 1 06. Accordingly, sagging of the sliver-holding surface which is caused by feedout driving by the rear roller 7 or 107 in the conventional apparatus does not occur at all.

Furthermore, the intermediate roller system is always rotated under tension, and therefore the sliver 12 or 112 can be fed smoothly to this intermediate roller system from the back roller 5, 105. This effect by the apron-driving system is especially prominent when the drafting rate is increased.

The porcupine roller 2 or 1 02 is arranged between the front roller 1 or 1 01 and the intermediate roller system 3 or 104 and is rotated in the same direction as the sliver delivery direction while the tips of needles 2a or 1 02a intrude into the sliver 12 or 112. Accordingly, the sliver 1 2 or 11 2 delivered between the front roller 1 or 101 and the intermediate roller system 3 or 104 undergoes a final draft and is stretched at this porcupine roller 2 or 102 so that the sliver 12 or 112 is delivered out from the front roller 1 or 1 01 with a predetermined thickness.Simultaneously, massive migration of fibres because of unevenness or lack of parallelism is prevented by the intrusion of the needle tips 2a or 1 02a into the sliver 12 or 112, and by this control action of the porcupine roller 2 or 102 the sliver is guided into the front roller 1 or 101 as a uniform fibre assembly. Hardly any draft is imparted between the back roller and the intermediate roller system but a predetermined amount of the draft is given between the intermediate roller system and the front roller. In the present invention, for example, the draft quantities are adjusted to 1.00 between the back roller and the intermediate roller system (the apron), to 0.90 in the zone of the porcupine roller, and the draft quantity is adjusted to 12.0 in the zone of the front roller.In this high draft zone, the sliver receives the control action of needles in the sufficiently stretched state. Accordingly, unevenness is reduced remarkably. Especially, massive migration of overlapping fibres at the time of ending of slivers is effectively controlled by the porcupine roller, and a sliver having a very good evenness can be manufactured.

As will be apparent from the foregoing description, according to the present invention, between a front roller and a back roller, at the gilling or bobinoir step of the worsted spinning process, a porcupine roller is provided before the front roller and an intermediate roller system comprising double aprons or a balloon roller and an apron is provided after the back roller to define a series of stations of a draft apparatus, and one of the aprons, or the apron, as the case may be, is driven and rotated by the foremost roller of rollers supporting said apron. By virtue of such characteristic features, the driven apron of the intermediate roller system is rotated in the state where the sliver-holding surface is kept under tension, and therefore the sliver supplied from the back roller is smoothly held and delivered out under tension without being bent.Accordingly, a high draft can always be given to the sliver precisely, and by the combing action of the porcupine roller fibres of the sliver are sufficiently controlled and unevenness due to the joining operation does not occur at all. Therefore, a sliver having a good uniformity and free of unevenness can always be spun out. Furthermore, in the present invention, the porcupine roller and the intermediate roller system comprising either a lower apron and an upper balloon roller, or a double apron 104, which is positively driven and rotated by the foremost roller, can easily be constructed by modifying and remodelling the conventional gill or bobinoir. Moreover, by such an arrangement of the porcupine roller and such driving of the apron, high draft is made possible and the effects of stabilising the quality, preventing formation of defective joints, eliminating working losses and improving the operational efficiency can be attained.

Claims (7)

1. A high draft apparatus for use in a worsted spinning process wherein, between a front roller and a back roller at the gilling or bobinoir step of the worsted spinning process, a porcupine roller is provided in advance of the front roller and an intermediate roller system is provided to follow the back roller in a series arrangement.

2. A high draft apparatus as claimed in claim 1, wherein said intermediate roller system comprises double aprons.

3. A high draft apparatus as claimed in claim 1, wherein said intermediate roller system comprises a balloon roller and an apron.

4. A high draft apparatus as claimed in claim 2, wherein one of said aprons is driven and rotated by the foremost roller of rollers supporting the apron.

5. A high draft apparatuses claimed in claim 3, wherein said apron is driven and rotated by the foremost roller of rollers supporting the apron.

6. A high draft apparatus as claimed in claim 4 or 5, wherein the circumferential surface of said foremost roller which drives the apron is roughened.

7. A high draft apparatus substantially as hereinbefore described with reference to Fig. 6 or Fig. 7 of the accompanying drawings.