| Title of Invention | ARRANGEMENT FOR PRODUCING A SPUN THREAD |
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| Abstract | Ar arrangement for producing a spun thread from a staple fibre strand comprises, a delivery roiler pair and an air jet aggregate arranged downstream therefrom. The latter is provided with a fibre transporting channel, which comprises a fibre guiding surface having a deflecting edge, said fibre guiding surface otherwise extending essentially piane and essentially parallel lo the nipping lins of the delivery roller par The fibre guiding surface ends in a vortex chamber arranged downstream of the fibre transporting channel in she area of an entry opening of a yarn withdrawal channel with a delivery edge which serves as a twist block. The fibre guiding surface becomes increasingly narrower Sue to laterally bordering walls o1 the fibre transporting channel and has its smallest width at the latest at a deflecting edge arranged upstream of the fibre delivery edge, |
| Full Text | Arrangement for producing a spun thread The present invention relate to an arrangement for producing a spum thread from a staple fibre strand delivered from a delivery roller pair to an airjet aggregate. comprising a fibre transporting channe arranged downstream of the delivery roller pair, said fibre transporting channel having an inlet opening and an exit opening and comprising a fibre guiding surface provided with a defecting edge, said fibre guiding surface otherwise extending essentially plane and essentially parallel to the nipping line of the delivery roller pair, which fibre guiding surface ends with a fibre delivery edge serving as a twist block in a vortex chamber downstream of the exit opening n the area of an eniry opening of a yam withdrawal channel. An arrangesment of this type is prior art in International Patent Application 02/2499:3. in this arrangement, a staple fiber strand, coming from a drafting and or another drafting aggregate, is guided through a fibre transporting channel to the enl y opening of a yarn withdrawal channel, whereby at first the front ends of the fibres held in the staple fibre strand are guided into the yam withdrawal chennel. while rear, free fibre ends are spread our and seized by the vortex stream and wound arourd the bound-in front ends already located in the entry opening of the yam wilhdrawal channel. whereby a thread with largely real twist is generated. The terms 'front" and "rear" ends of the fibres relate in this context to the transport direction of the stap-e fibre strand. The higher the drafts and the spinning speeds are, the widar the staple fibre strand is which is transported from delivery roller pair to the airjet aggregate. As the width if the staple fibre strand increases, however, it becomes more difficult to insert the fibres to be spun into the airjet aggregate without fluctuations in material mass. In the case of the known arrangement in which the fiber transporting channel has a largely conslani cross section, it has been shown that a percentage of the fibres go past the yarn withdrawal channel and are then subsequently sucked in again because of the vacuum prevailing in the airjet aggregate. This results for a short time in an accumulation of fibres, which causes an accumulation of undesirable sluos. In a non-generic arrangementt according to European patent 854 214. It is known that the fibre transporting channel, beginning at its intet opening, narrows in a XXX fashion This known arrangement has however, not a fibre delivery edge serving as a twist block, but rather the twist block is formed along the entire length of the fibrs transporting channel by a helix-shaped fibre guiding surface. It is an object of the present invention to avoid to a great extern mass ftuclua lions an arrangement of the above mentioned type and thus to increase the spinning speed while retaining a satisfactory yarn quality. This object has been achieved according to the present invention in that the fibre guiding surface tapers due to lateral bordering walls of the fibre transporting channel and has reached its narrowest point by the time it reaches the deflecting edge Beginning with an approximately oval inlet opening, whose larger width extence parallel to the nipping line of the delivery roller pair, the fiber transporting channel tapers relatively rapidiy so that the narrowest point is reached at the defleding edge of the fibre guiding surface. This smallest width is essentially retained up to the fibre delivery edge, with the result that the fibres to be spun are transported through the entry opening into the yarn withdrawal channel without any significant loss of fibre This leads no: only to an increase in the yarn quality, but also perrnits significanty higher delivery and spinning speeds. This arrangement according to the present invention can be further designed in that the fibre guiding surface reaches atleast approximately its smallest width at an that cdge arranged upstream of the dellecting edge. The smallest width of the fibre guiding surface should correspond to at the most, three times the diametsr of the entry opening ot the yarn withdrawal channel, or preferably even mensure only trwice this diameter. BRIEF DESCRIPTION OF THE PRAWINGS These and further objects, fealures and advantages cf the present invention will become more readily apparent from the followinng detailed description thereof when taken in conjunction with the accompanying drawings wherein: Figure 1 is ten times enlarged an axial intersection of the arrangement according to the present invention. Figure 2 is a cross section of an airjet body of the eirjet aggregate along the intersection surface II-II of Figure 1. Figure 3 is an axial intersection along the intersection surface III-III of figure 1. Figure 4 is an axial intersection similar to figure 3 of an arrangement having a different design, Figure 5 is a view in the direction of arrow V of figure. 1 of the inlet opening .of the fibre transporting channel DETAILED DESCRIPTION OF THE DRAWINGS The arrangement according to Figures 1 to 3 and 5 comprises a delivery device 1 for feeding a staple fibre strand 2 to be spun, also comprising an airjet aggregate 3. in which the steple fibre strand 2 is imparted the necessary twist requires the soinning of a thread 4. The delivery device 1 comprises a delivery roller pair 5, 6 which is arranged upstream of the airjet aggregate 3 at a Short distance therefrom these can be the front XXX of a drafting unit (not otherwise shown). A drafting unit of this hind drafts in the known way a fed sliver of a roving to a staple fibre strand 2 of the desired timeness. The delivery device 1 however can be alternatively a nipping roller pair of another drafting device or any other aggregate arranged upstream of the airjet aggregate 3. A nipping line is denoted by the number 7, at which the staple fibre strand 2, fed n delivery direction A, is held nipped before it runs into the airjet aggregate 3. The lotter generates the twist for the thread 4 to be spun, and delivers the thread 4 in yarn withdrawal direcifon 8 by means of a withdrawal roller pair (not shown). The airjet aggregate 3 also compnses an airjet body 8 with a fibs transporting channel 8 and a vortex chamber 10. A fluid device generates a vortex current in the vortex chamber to by means of compressed air being blown in through air supply nozzwes 11 which run langenttially into the vortex chamber 10. The compressed air exiting out of the mouths of the air supply nozzles 11 is removed via an air evacuation duct 12 which surrounds, in the manner of a circular ring, a staliona y spindle-like component 13. which in lum surrounds a yarn withdrawal channel 14. Downstream of an exit opaning 15 of Irte fibre transporting channel 9, a fibre deliver' edge 16 of a fiber guiding surface 17 is arranged as a twist block, which fiber guiding surface 17 is arranged eccentrically to the yarn withdrawal channel 14 in the erea of its enty opening 18. In the airjet aggregate 3, the fibres to be spun are held on the one hand in the staple fibre strand 2 and thus guided from the exit opening 15 of the fibre transporting channel 9 essentially without twist into the yarn withdrawal channel 14. On the other hand the fibres in the areg between the fibre transporting channel 9 and the yarn withdrawal channel 14 are subject to the effect of the vortex current, which causes the fibres of at least their end areas to be driven radially away from the entry opening 18 of the yarn withdrawal channel 14. The threads 4 produced by the described process have a core of fibres, or fibre areas, extending essentially in thread XXX direction and without any significant twist, and an outer area in which the fibres or fibre areas are wound around the core. Basing the formation of the thread structure on an idealized process for the purposes, of greater clarity, the front ends of the fibres, in particular those rear areas still held upstream in the fibre transporting channel 9, essentially directly reach the yarn withdrawal channel 14, but rear fibre areas in particular when they are no longer held in the entry area of the fibre feed channel 9, are pulled out of the staple fibre strand 2 by the vortex formation and then wound around the forming thread 4. In and case, fibres aie bound into the forming thread 4. during which they are pulled through tne yarn withdrawal channel 14, while at the same time they are also subject to the vortex current, which accelerates them XXX. that is from the entry opening 11 of the yarn withdrawal channel 14. and draws them into the air evacuation duct 12. The fibre areas pulled out or the staple fibre strand 2 by the vortex current form a fibre vortex which runs into the entry opening 18 of the yarn withdrawal channel 14; the longer parts of which wind themselves spiral-like around the spincle-shaped component 13 and are pulled in this spiral against the force of the current in the air evacuation duct 12 against the entry opening 16 of the yarn withdrawal channel 14. According to the embodiment shown in Figures l and 3. there are four compressed. air supply nozzles 11 overall per airjet aggregate 3. which are each worked into the airjet body 8. An XXX space 19 surrounding the airjet body 8 XXX is XXX to a source for compressed air in a way not shown. The compressed air reaches the individual air supply nozzles 11 from the annuter space 19 via the recesses 20 worked into the outer contour of the airjet body 8. The annular XXX 19 is seated off from the outside by means of a wall of a housing 21. The fibre transporting channel 9 comprises an inlet opening 22, which, according to Figure 5, has a larger width parallel to the nipping line 7 of the delivery roller pair 5,-3 than perpendicular thereto. Thus the fact that the staple fibre slrand 2 XXX into the airjet aggregate 3 has its larger width lengthwise of the nipping line 7. is inihally taken into consideration. In the fibre transporting channel 9 the staple fiber strand.2 is guided along a fiber guiding surface 17. which comprises a deflecting edge 23 in its path. This results in a certain loosening of the transported staple fibre sirand 2 before it runs a short distance over the fibre guiding- surface 17 aher it has exitel from the exit opening 15 of the fibre transporting channel 9, and ends directly upstream of the entry opening 18 of the yarn withdrawal channel 14 at a so-called fibre delivery edge 16, which functions as a twist block. This twist block is vital as it prevents the twist imparted to the thread 4 from running back towards the nipping line 7 of the delivery roller pair 5.6. In order that the staple fibre strand 2 is sufficiently narrow and condensed to an optimal width before it reaches the entry opening 13 of the yarn withdrawal channel 14, laterally bordering walls 24 and 25 are provided in the fibre transporting channel 9 as can be seen in particular in Figure 3, which cause the fibre guiding surface17 to become increasingly narrower and to reach its smallest width at the deflecting edge 23. With this embodiment, the inherent disadvantageous slubs in the above rnentioned prior art are avoided to a great extant, so that higher spinning and delivery speeds are also possible. In a variation according to Figure 4, it can be seen that alternatively the fibre guiding surface 17 can reach a width which is at least approximately its narrowost at an inlet edge 26 arranged upstream of the deflecting edgc 23. This smallest width corresponds, for the purposes of the present invention, only twice to three times the diameter of the entry opening 18 of the yarn withdrawal channel 14. CLAIMS. 1. Arrangement for producing a spun thread from a staple fibre strand deliverey from a delivery roller pair to an airjet aggregate, comprising a fiber transporting channel arranged downstream of the delivery roller pair, XXX fibre transporting channel having an inlet opening and an end opening and comprising a fibre guiding surface provided with a deflecting edge. said fiber guiding surface otherwise extending essentially plane and essentially parallel to the nipping line of the delivery roller pair, which fibre guiding surface and with a fibre delivery edge serving as a twist block in 2 vortex chamber downstream of the exit opening in the area of an entry opening of a yarn withdrawal channel, characterized in that the fibre guiding surface (17) XXX due to laterally bordering walls (24, 25) of the fibre transporting channel (9) and reaches its smallest width at the deflecting edge (23). 2. An arrangement according to claim 1, characterized in that the fibre guiding surface (17) has at least approximately its smallest width at an XXX edge (26) arranged upstream of the deflecting edge (23). 3. An arrangement according to claim 1 or 2, characterized in that the smallest width of the fibre guiding surface (17) corresponds at the most to three times the diameter of the entry opening {18) of the yarn withdrawal channel (14). 4. An arrengement according to claim 3 wherein the smallest width of the fiber guiding surface (17) corresponds at the most to twice the diameter of the entry opening (18) of the yarn withdrawal channel (14). Ar arrangement for producing a spun thread from a staple fibre strand comprises, a delivery roiler pair and an air jet aggregate arranged downstream therefrom. The latter is provided with a fibre transporting channel, which comprises a fibre guiding surface having a deflecting edge, said fibre guiding surface otherwise extending essentially piane and essentially parallel lo the nipping lins of the delivery roller par The fibre guiding surface ends in a vortex chamber arranged downstream of the fibre transporting channel in she area of an entry opening of a yarn withdrawal channel with a delivery edge which serves as a twist block. The fibre guiding surface becomes increasingly narrower Sue to laterally bordering walls o1 the fibre transporting channel and has its smallest width at the latest at a deflecting edge arranged upstream of the fibre delivery edge, |
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| Patent Number | 216310 | ||||||||
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| Indian Patent Application Number | 01369/KOLNP/2005 | ||||||||
| PG Journal Number | 11/2008 | ||||||||
| Publication Date | 14-Mar-2008 | ||||||||
| Grant Date | 12-Mar-2008 | ||||||||
| Date of Filing | 15-Jul-2005 | ||||||||
| Name of Patentee | MASCHINENFABRIK RIETER AG | ||||||||
| Applicant Address | KLOSTERSTRASSE 20, CH-8406 WINTERTHUR, SWITZERLAND | ||||||||
Inventors:
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| PCT International Classification Number | D01H 1/115 | ||||||||
| PCT International Application Number | PCT/EP2003/011768 | ||||||||
| PCT International Filing date | 2003-10-24 | ||||||||
PCT Conventions:
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