Title of Invention

"DRAWING FRAME OF A STAPLE FIBRE SPINNING MACHINE COMPRISING A CENTRAL FIBRE GUIDE"

Abstract

A drawing frame of a staple-fibre spinning machine, in which a sliver (F) is drafted, with a condenser zone (11) which is arranged downstream of the drawing frame (1) and which extends between an exit press roller (9) of the drawing frame (1) and a delivery press roller (12), which are supported on a lower cylinder (10), and comprises a condenser component (13) with a condenser channel (14), which is supported on a lower cylinder (10) in a play-free manner and serves for condensing the fed, drafted sliver (F), characterised in that the axes of the condenser channel (14) and of the fed sliver (F) are aligned essentially parallel, preferably coaxially, at the entry of the condenser channel (14).

Full Text

The present invention relates to drawing frame of a staple fibre spinning machine comprising a central fibre guide. The invention relates to a drawing frame for a staple fibre spinning machine with a condenser zone arranged downstream, according to the preamble of patent claim 1. The conversion of natural- and artificial fibres into a yarn demands a series of part working procedures. The last working step is usually called fine spinning. With this, the spun yam obtains its final fineness and strength. Fine spinning demands a considerable proportion of the effort with regard to the whole yarn manufacturing process. Ring spinning in staple fibre spinning machines, known from the state of the art, comes closest to classical hand spinning with spinning wheels. With this, the spun yarn is wound onto a rotating spinning spindle. Essentially three machines are required for ring spinning. A roving which is also called a carded sliver, is produced from a sliver by the flyer. The yarn with the required fineness is produced from the roving by the staple fibre spinning machine, and spun onto a small bobbin, the cop. The winding machine then puts the yarn together from many cops and produces a yarn bobbin ready for use, having a weight of a few kilos. On the staple fibre spinning machine, the roving is drafted to the required fineness of the thread, and the twist of the fibres required for spinning the yarn is produced. The machine as a rule has a double-sided design, and on each side has a plurality of spindles = spinning locations. A drawing frame is allocated to each spinning location. Thereby, in many cases, it is the case of a so-called three-cylinder drawing frame. This drawing frame has a preliminary drafting field and a main drafting field. The supplied roving is drafted to the desired fineness in the drawing frame and leaves the drawing frame at the nip line of an exit roller pair as a relatively wide sliver. This sliver is twisted with the help of the single yarn twist, and is twisted together into the finished yarn. Thereby, a so-called spinning triangle is formed subsequent to the nip line of the exit roller pair of the drawing frame, in which the fibres fed by the drawing frame are led together and integrated into the yarn structure. Not all fibres are caught in the spinning triangle. Edge fibres may become lost or become incompletely attached onto the twisted yarn. The fibres located at the edges of the spinning triangle, on being subjected to the twisting, are strained to a considerably greater extent than the fibres located in the middle of the spinning triangle. Thus in the completed yarn, the fibres lying at the periphery are therefore pretensioned to a greater extent that the fibres in the core of the yarn. Then, given a correspondingly high loading of the yarn, the fibres at the periphery which are pretensioned to a greater extent break first. For this reason, the finished twisted yarn does not have the strength which is should have as a sum of the individual strengths of the individual fibres. The fibres which are attached in an uncontrolled manner protrude from the twisted yarn, and lead to an increased and undesired hairiness of the yarn. An increased yarn hairiness may be equated to a reduction in quality. In order to avoid the spinning triangle and its disadvantageous consequences as much as possible, with drawing frames of modern staple fibre spinning machines, the drafting zone is supplemented by a condenser zone, in which the wide sliver supplied by the exit roller pair is led together in a manner which is as compact as possible. Only the sliver condensed or compacted in such a manner is twisted together into the finished yarn after leaving the condenser zone. It is suggested by the applicant in the international PCT application No. PCT/CH003/00001 to arrange the condenser zone downstream of the drawing frame of a staple fibre spinning machine. The condenser zone extends between an exit press roller of the drafting zone and a delivery press roller at the exit of the condenser zone. The two press rollers are supported on a lower cylinder. A geometrically-mechanically acting condenser component is arranged between the two press rollers, and comprises a condenser channel. The condenser component is preferably pressed against the lower cylinder by way of magnetic force and/or spring force. The drawing frame with a condenser zone arranged downstream already provides yarns having a good quality. However, the desire exists to further improve the yarn quality. It is therefore the object of the present invention, in this respect, to improve a drawing frame of a staple fibre spinning machine with a condenser zone arranged downstream, in order to achieve very high yarn qualities. The modifications should not compromise the basic construction of the drawing frame with a condenser zone arranged downstream. They should be able to be implemented in a simple and inexpensive manner and also permit a retrofitting of existing drawing frames. The solution of these objects lies in a drawing frame for a staple fibre spinning machine with a condenser zone arranged downstream, which comprises the features specified in the characterising section of patent claim 1. Further formations and/or advantageous embodiment variants of the invention are the subject-matter of the dependent patent claims. The invention suggests modifying a drawing frame for a staple fibre spinning machine with a condenser zone arranged downstream, to the extent that the axes of the condenser channel and of the fed sliver are aligned essentially parallel, preferably coaxially, at the entry into the condenser channel. By way of fact that the axis of the condenser channel and the axis of the fed sliver at the entrance into the condenser channel run essentially parallel and are preferably aligned coaxially, the friction forces which occur on the left and right delimiting surfaces of the condenser channel on leading through the sliver, are essentially equally large. Transverse forces which may lead to a non-uniform condensing of the sliver are largely avoided by way of this. The transverse forces which act on the condenser component on leading through the sliver and which may change the axial alignment of the condenser channel are also kept as low as possible by way of the measure according to the invention. The alignment of the axes of the condenser channel and of the fed sliver only requires slight constructional adaptations of the drawing frame and of the condenser zone arranged downstream. The solution is simple and in particular is designed for an inexpensive retrofitting of existing systems. In order to ensure that the axis of the fed sliver runs parallel, ideally coaxially, to the axis of the condenser channel of the condenser component, means are provided which lead the sliver drafted in die drawing frame to the condenser channel is a largely centric manner. In a first variant of the invention, the means comprise at least one fibre guide which is provided in the region of a nip line of the exit press roller with the lower cylinder. The fibre guide is preferably arranged upstream of the exit press roller with respect to the transport direction of the sliver. The fibre guide comprises a passage channel for the sliver, which is arranged essentially centrically with respect to the condenser channel of the condenser component. The fibre guide ensures a uniform alignment of the sliver drafted in the drawing frame. The arrangement in front of the nip line of the exit press roller with the lower cylinder saves space. It ensures that the sliver drafted in the drawing frame already reaches the nip line of the exit press roller with the lower cylinder in a centred manner. The entry into the condenser channel of the condenser component lies just behind the nip line. By way of this, it is ensured that the fed sliver retains is transport direction which is aligned with respect to the axis of the condenser channel. In an alternative variant of the invention, the means comprise a fibre centring organ arranged within the drawing frame, with a passage channel for the sliver which is arranged essentially centrically with respect to the condenser channel of the condenser component. The fibre centring organ, with respect to the transport direction of the sliver, is arranged in front of an apron roller of an apron drafting device. The alternative arrangement of a fibre centring organ in front of the apron roller of the apron drafting device also ensures that the sliver drafted in the drawing frame reaches the nip line of the exit press roller with the lower cylinder in an already centred manner. A further alternative of the invention may envisage a fibre guide as well as a fibre centring organ being provided. The fibre centring organ thereby ensures a relatively early pre-centring of the drafted sliver. With regard to the drawing frame, it is advantageously the case of a so-called three-cylinder drawing frame with a preliminary drafting field and a main drafting field. The main drafting field is formed by an apron drafting device. The fibre centring organ thereby, with respect to the transport direction of the sliver, is advantageously arranged in front of an apron roller of the apron drafting device. On account of this, the sliver which is fed as a so-called roving is already centred before the main drafting field. The pre-centring simplifies the subsequent centring of the drafted sliver in the fibre guide. The condenser channel at its entrance has a width which is at least as equally large as the passage width of the fibre guide or of the fibre centring organ. By way of this, it is ensured that the sliver may enter into the condenser channel of the condenser component over its complete width. The condenser channel narrows towards its exit, so that the sliver may be led together and condensed to the desired extent. With the simultaneous presence of a fibre guide and a fibre centring organ, the passage width of the fibre guide is equally large or larger than the passage width of the fibre centring organ. By way of this, it is ensured that all fibres of the sliver drafted in the main drafting field are encompassed by the fibre guide. In one very useful embodiment variant, the condenser component is fixed in its position by magnetic force. Thereby, the condenser component with its contact surface which preferably has essentially the same radius as the peripheral surface of the lower cylinder, is pressed against the lower cylinder without play by way of magnetic force. For improving the matching of the alignment of the axes of the condenser channel of the condenser component and of the fed, drafted sliver, the condenser component comprises at least two magnets, which are arranged symmetrically to the condenser channel and to a peripheral sleeve of the exit press roller. The magnets arranged symmetrically to the condenser channel tend to align the condenser component to the lower cylinder in an exactly axially parallel manner. The peripheral sleeve usually consists of hardened steel and is accordingly ferromagnetic. It is located within the range of influence of the magnets on account of the relatively restricted spatial conditions. The symmetrical arrangement of the magnets to the peripheral sleeve has the effect that any occurring interactive forces of the magnets with the peripheral sleeve are effected at both sides of the condenser channel. An inadequate alignment of the condenser channel which could occur as the result of effect of force on only one side, is effectively prevented by way of this. The peripheral sleeve is usually assembled on a cylindrical shaft. The cylindrical shaft consists of a non-magnetisable material, so that the effect of the magnetic forces is not distorted at one side on account of this shaft. A staple fibre spinning machine advantageously comprises a plurality of drawing frames with condenser zones arranged downstream, which are arranged next to one another. The exit press rollers and the apron rollers in each case of two drawing frames arranged next to one another thereby are arranged in pairs at a distance to one another on a cylindrical shaft. The fibre guides and/or the fibre centring organs in the adjacent drawing frames, in one embodiment variant of the invention, are in each case grouped into units which may be commonly assembled. The fibre guides and/or fibre centring organs which are grouped in pairs into units, may for example be axially fixed on the lower cylinders for the exit press rollers or on the apron press rollers. This simplifies the assembly. Further advantages and features are to be deduced from the subsequent description of an exemplary embodiment variant of the invention, with reference to the schematic drawings. There are shown in: Fig. 1 a schematic representation of a drawing frame designed according to the invention, with a condenser zone arranged downstream; Fig. 2 a principle representation of the drawing frame with a condenser zone, according to Fig. 1; Fig. 3 a partly sectioned view of an exit press roller with fibre guide and a condenser component arranged downstream; and Figure 4 an apron press roller with a fibre centring organ arranged upstream. The terms "arranged downstream" and "arranged upstream" used in the following, in each case relate to the transport direction of a sliver through a drawing frame of a staple fibre spinning machine. Fig. 1 and 2 schematically show a drawing frame designed according to the invention, which in its entirety has the reference numeral 1. With regard to the drawing frame 1, it is the case of a so-called three-cylinder drawing frame with a preliminary drafting field 4 and a main drafting field 8 for a sliver F. The transport direction of the sliver F is indicated by arrows. The preliminary drafting field 4 extends from an entry press roller 2 and an entry lower cylinder 3 up to a middle roller pair, which is formed by an apron roller 5 and an associated middle lower cylinder 6. Double aprons 7 of the main drafting field 8 are led over the apron roller 5. The main drafting field 8 extends from the middle roller pair 5,6 up to an exit press roller 9 which is supported on a lower cylinder 10. The contact region of the entry press roller 2 with the entry lower cylinder 3 defines an entry nip line A. The contact region of the apron roller 5 with the associated middle lower cylinder 6 is indicated as a nip line B. The contact region of the exit press roller 9 with the lower cylinder 10 finally defines an exit nip line C. A condenser zone 11 which extends between the exit nip line C and a supply nip line D which is formed by the contact region of a delivery press roller 12 with the lower cylinder 10, is arranged downstream of the three-cylinder drawing frame 1. Thereby, the lower cylinder 10 usually has a somewhat larger diameter than the remaining lower cylinder at the exit of the drawing frame. A condenser component 13 with a condenser channel 14 is arranged in the condenser zone 11. The condenser component 13 on account of its constructional design acts in a geometric-mechanical manner and condenses the widened sliver F led through the condenser channel 12. The condenser component 13 with its contact surface 15 is supported on the lower cylinder 10, preferably in a play-free manner. The contact surface 15 of the condenser component 13 with respect to the lower cylinder 10, is thereby preferably designed such that its radius largely corresponds to that of the supporting lower cylinder 10. By way of this, one prevents the fibres getting between the contact surface 15 of the condenser component 13 and the lower cylinder 10. The condenser component 13 is advantageously fixed in its position by magnetic force. The condenser channel 14 of the condenser component 13 has a relatively large width at the entry side, in order to be able to accommodate the complete width of the sliver F transported from the exit press roller 9 and the lower cylinder 10. The width of the condenser channel 14 tapers along its direction of extension and at the exit has the smallest passage width. The fibres of the drafted sliver F are led together on passing the tapering condenser channel 12, and the sliver F is condensed before it is twisted into a yarn after leaving the supply nip line D In order for the sliver F to be subjected to as uniform as possible friction forces on the lateral delimitation surfaces of the condenser channel 12 on transport through the condenser component 13, the axes of the condenser channel 14 and the supplied sliver F are aligned to one another and run essentially parallel to one another. The axes are preferably aligned in a coaxial manner. By way of this, the transverse forces which may lead to a non-uniform condensing of the sliver F are largely avoided. The transverse forces acting on the condenser component on leading through the sliver F and which may change the axial alignment of the condenser channel, are also kept as low as possible by way of the measure according to the invention. A fibre guide 16 is arranged upstream of the exit press roller 9 for improving the alignment of the axes of the condenser channel and the transported drafted sliver F. The fibre guide 16 is assembled for example on the exit press roller 9 and is supported on the lower cylinder 10. It has a passage channel 17 whose passage width is equally large or smaller than the width of the condenser channel 14 at the entry of the condenser component 13. As is indicated in Fig. 1 and 2, a further fibre centring organ 18 which is arranged upstream of the apron press roller 5 may be provided for further improving the centric alignment of the sliver F and of the condenser channel 14 of the condenser component. The fibre centring organ 18 is assembled for example on the apron press roller 5 and is supported on the middle lower cylinder 6. It has a passage channel 19 whose passage width is equally large or smaller than the passage width of the passage channel 17 of the fibre guide 16. The fibre centring organ 18 may also be provided on the apron press roller 5 in place of the fibre guide 16 in an alternative embodiment variant of the invention. Fig. 3 schematically represents a further formation of the invention for improving the axial alignment of the condenser component 13 and of the transported sliver. Thereby, it is shown that the exit press roller 9 comprises a peripheral sleeve 91 which is assembled on a cylindrical shaft 90. The cylindrical shaft 90 in each case carries two peripheral sleeves 91 and 91' which belong to two adjacent drawing frames. The peripheral sleeves with the press rollers common today, are formed by the outer rings of the mounting. They consist of hardened steel and may accordingly be magnetised. Each peripheral sleeve 91,91' carries an elastic cover 92,92' which is assembled exactly symmetrically to the axial extension of the peripheral sleeve 91,91'. The condenser component 13 with the condenser channel 14 is supported on the lower cylinder without play and is fixed with respect to its position by magnetic force. For this, magnets 130 are arranged on both sides of the condenser channel 14 and cooperate with the material of the lower cylinder. Since the peripheral sleeve 91 consists of a magnetisable material, the condenser channel 13 also aligns symmetrically to the peripheral sleeve 91 with an exact symmetrical arrangement of the at least two magnets 130 to the condenser channel 14. The fibre guide 16 is for example seated on the free ends of the peripheral sleeve 91 and is axially positioned by the cover 91. Alternatively, a groove may be provided in the lower cylinder for example, in which the fibre guide is axially guided and aligned. So that the exact, axial alignment of the condenser component 13 to the peripheral sleeve 91 is not upset by an interaction of the magnets 130 with the cylindrical shaft 30, the shaft 90 advantageously consists of a non-magnetisable material. Fig. 4 shows the apron roller 5 and the middle lower cylinder 6 from the view of an arriving sliver. The apron roller 5 comprises a peripheral sleeve 51 on which an elastic cover 52 is assembled. The peripheral sleeve 51 is assembled on a cylindrical shaft 50 on whose second end a further peripheral sleeve of an apron roller of the adjacent drawing frame may be arranged. The fibre centring organ 18 with the passage channel 19 is assembled for example on a lateral continuation of the peripheral sleeve 51 of the apron roller 5. The fibre centring organs of adjacent drawing frames may be grouped together into a construction unit which are fixed axially by bearing parts carrying the middle lower cylinder.The invention has been explained with the example of a drawing with a condenser zone arranged downstream, which for achieving an as good as possible axial alignment of the sliver and of the condenser channel of the condenser component, comprises a fibre guide, a fibre centring organ and a shaft of a non-magnetisable material connecting adjacent exit press rollers. It is to be understood that the application of a fibre guide alone or in combination with a non-magnetisable shaft, or the application of a shaft of a non-magnetisable material is also encompassed by the general inventive idea. In this context, it is to be pointed out that the application of a fibre guide and, as the case may be, a further fibre centring organ, may also be effected in combination with condenser components which may also be fixed in their axially aligned position by means other than magnetic ones, for example by way of loading with a spring force. This too already leads to a significant improvement of the axial alignment of the condenser channel and of the transported drafted sliver. We Claim: 1. A drawing frame of a staple-fibre spinning machine, in which a sliver (F) is drafted, with a condenser zone (11) which is arranged downstream of the drawing frame (1) and which extends between an exit press roller (9) of the drawing frame (1) and a delivery press roller (12), which are supported on a lower cylinder (10), and comprises a condenser component (13) with a condenser channel (14), which is supported on a lower cylinder (10) in a play-free manner and serves for condensing the fed, drafted sliver (F), characterised in that the axes of the condenser channel (14) and of the fed sliver (F) are aligned essentially parallel, preferably coaxially, at the entry of the condenser channel (14). 2. A drawing frame as claimed in claim 1, wherein means are provided which feed the sliver (F) drafted in the drawing frame (1) largely centrically to the condenser channel (14). 3. A drawing frame as claimed in claim 2, wherein the means comprise at least one fibre guide (16) which is provided in the region of a nip line (C) of the exit press roller (9) with the lower cylinder (10), preferably is arranged in front of the exit press roller (9) with respect to the transport direction of the sliver (F), and comprises a passage channel (17) for the sliver (F) which is arranged essentially centrically with respect to the condenser channel (14) of the condenser component (13). 4. A drawing frame as claimed in claim 2 or 3, wherein the means comprise a fibre centring organ (18) arranged within the drawing flame (1), with a passage channel (19) for the sliver (F), which is arranged essentially centrically with respect to the condenser channel (14) of the condenser component (13), and that the fibre centring organ (18), with respect to the transport direction of the sliver (F), is arranged in front of an apron roller (5) of an apron drafting device (7). 5. A drawing frame as claimed in claim 3 or 4, wherein the condenser channel (14) has an entry width which is equally large or larger than a width of the passage charnel (17) of the fibre guide (16) or than a width of the passage channel (19) of the fibre centring organ (18). 6. A drawing frame as claimed in claim 5, wherein given the simultaneous presence of a fibre guide (16) and of a fibre centring organ (18), the passage channel (17) of the fibre guide (16) has an entry width which is equally large or larger than the width of the passage channel (19) of the fibre centring organ (18). 7. A drawing frame as claimed in one of the preceding claims, wherein the condenser component (13) with its contact surface (15) which preferably has essentially the same radius as the peripheral surface of the lower cylinder (10), is pressed against the lower cylinder (10) in a play-free manner by magnetic force, arid the condenser component (13) comprises at least two magnets (130) which are arranged symmetrically to the condenser channel (14) and to a peripheral sleeve (91) of the exit press roller (9). 8. A drawing frame as claimed in one of the preceding claims, wherein the peripheral sleeve (91) of the exit press roller (9), which consists preferably of hardened steel, is assembled on a cylindrical shaft (90) which consists of a non-magnetisable material. 9. A staple fibre spinning machine with a plurality of drawing frame (1) with condenser zones (11) arranged downstream as claimed in any of the preceding claims.

Documents:

2312-DELNP-2006-Abstract-(25-07-2008).pdf

2312-delnp-2006-abstract.pdf

2312-DELNP-2006-Claims-(25-07-2008).pdf

2312-DELNP-2006-Claims-(26-02-2009).pdf

2312-delnp-2006-claims.pdf

2312-delnp-2006-complete specification (granted).pdf

2312-DELNP-2006-Correspondence-Others-(25-07-2008).pdf

2312-delnp-2006-correspondence-others.pdf

2312-delnp-2006-description (complete)-25-07-2008.pdf

2312-delnp-2006-description (complete).pdf

2312-DELNP-2006-Drawings-(25-07-2008).pdf

2312-delnp-2006-drawings.pdf

2312-DELNP-2006-Form-1-(25-07-2008).pdf

2312-delnp-2006-form-1.pdf

2312-delnp-2006-form-2.pdf

2312-delnp-2006-form-3.pdf

2312-delnp-2006-form-5.pdf

2312-DELNP-2006-GPA-(25-07-2008).pdf

2312-delnp-2006-gpa.pdf

2312-delnp-2006-pct-210.pdf

2312-delnp-2006-pct-301.pdf

2312-delnp-2006-pct-304.pdf

2312-delnp-2006-pct-308.pdf

2312-DELNP-2006-Petition-137-(25-07-2008).pdf