CN1602373A - Stretching machines for endless textile machines with fiber belt compressors - Google Patents

Abstract

A drawing machine (1) of a ring spinning machine for spinning is described. The drawing machine (1) has a drawing zone (7, 8) and compression elements (11, 21, 31, 41) with a geometric-mechanical action of compression channels (12, 22, 32, 42) for drawing and widening the fiber band (F). The compression element (11) is arranged in a compression zone (16), said compression zone (16) being between the outfeed pressure roller (8) of the stretching zone (7, 10) and the outfeed pressure roller (15) at the output of the compression zone (16), and being provided with conveying means supporting the fibrous web (F) along the entire conveying stretch (A, B) passing through the compression zone (16).

Description

Stretching machines for endless textile machines with fiber belt compressors

technical field

The invention relates to a stretching machine for an endless textile machine with a compressor for the fiber strip as described in the preamble of claim 1 . The invention also relates to a component for use in a stretching machine according to the invention.

Background technique

Converting natural and man-made fibers into yarn requires a series of sub-processes. The last processing stage is generally called worsted spinning. The yarn spun here acquires its final fineness and tenacity. Said worsted spinning takes a considerable part of the cost of the whole spinning process. In succession to the traditional hand spinning with a spinning wheel, there is the circular spinning known from the prior art. The yarn spun here is wound on a rotating yarn shaft. Essentially three machines are required for endless weaving. A gray yarn, also called untwisted sliver, is produced from the fiber strip with a flyer. A yarn with the necessary tenacity is produced from the raw yarn with an endless spinning machine and spun onto small bobbins, bobbins. The winder gathers together yarn from many bobbins and produces ready-to-use bobbins weighing about a few kilograms.

On the ring spinning machine the yarn is drawn to the desired fineness and the strands of fibers required for spinning are obtained. The machine is generally designed on two sides and has a plurality of spindles or spinning positions on each side. A stretching machine is arranged for each spinning position. These are mostly so-called three-cylinder stretching machines. This stretching machine has a pre-stretching zone and a main stretching zone. The supplied gray yarn is brought to the desired fineness in the drawing machine and is a relatively wide ribbon of fibers when the nip line of the output roll pair leaves the drawing machine.

The fiber strips are twisted by means of spinning and assembled into a finished yarn. Here, a so-called spinning triangle is formed on the nip line of the output roller pair of the final drawing machine, in which the fibers supplied by the drawing machine are joined together to form a yarn structure. Not all fibers are accommodated in the spinning triangle. Edge fibers may be lost or only partially accumulated into the spinning yarn. The fibers on the edge of the spinning triangle are substantially strongly tensioned into the fibers in the middle of the spinning triangle when the rotation is initiated. The fibers at the periphery in the finished yarn are therefore more prestressed than the fibers in the core of the yarn. With correspondingly higher yarn loads, the yarns which are subjected to a higher surrounding prestress are the first to break. The finished rolled yarn therefore does not have the corresponding tenacity that should become a single yarn. The fibers accumulate uncontrollably away from the wound yarn and lead to increased unwanted yarn fuzzing. Increased fuzziness equates to compromised quality.

In order to avoid the spinning triangle and its unfavorable consequences as far as possible, the stretching zone in the stretching machine of modern ring spinning machines is extended by a compression zone in which the as dense as possible collection of wide fiber to output. Only the thus compressed or densified fiber strips are twisted together after the compression zone to produce yarn. A pneumatically operated compression device is known, for example, from the specification 1646e-BBAB-15 of Fa. Rieter, Winterthur. This known pneumatic compression device consists of a perforated cylinder in which there is predominantly a low pressure. This low pressure creates an air flow through the perforated rollers thereby compressing the fiber ribbon being conveyed through said rollers as required. Pneumatically operated compressors are expensive to purchase and maintain. Generating the low pressure required for compression requires a relatively high energy input. For this reason, some of the components required for compressing the fiber strips are subject to relatively high wear. The compacted yarn produced by pneumatic compression, although of better quality, is significantly more expensive than conventional ring spinning.

Drawing machines of ring spinning machines equipped with geometrically-mechanically acting compression devices are also known. They can generally be realized at reasonable cost. Each compression device here contains a drill block-like compression element which is arranged in the conveying level of the fiber strip. On its side facing the fiber web, the compression element is provided with a trough-like compression channel which expands funnel-shaped on the input side of the fiber web and is formed tapering in the conveying direction of the fiber web. When the fiber strip is conveyed by the compression element, the fibers are pressed together and compressed to the desired diameter through the narrowing compression channels.

In a known embodiment variant, in the main stretching zone of the stretching machine, a relatively small configured compression element is arranged between the stretching belt arranged in the main stretching zone and the pair of delivery rollers. The tension and compression of the fiber strips take place simultaneously in this arrangement of the compression parts. The uniform stretching of the fiber strip is disturbed here. To create the position of the compression part, the distance between the nip line of the output roller and the tension belt was increased. This also increases the distance over which the fibers are not transported. Interference with uniform stretching and the distance over which the yarn must be returned without conveying can lead to inhomogeneities that impair its quality. Compression parts are disturbed when manipulating the stretching machine and are easily lost due to their relatively small construction.

Theoretically there is also the possibility of arranging geometrically-mechanically acting compression elements in the compression zone following the tension zone.

In such an arrangement, the fiber must traverse the distance between the output roller pair and the supply roller pair provided at the exit of the compression zone without supporting conveying means. In many materials, such as in the case of cotton, most fibers are shorter than the distance to be traversed in the compression zone. Arrangement of the compression element in the subsequent compression zone is only possible here if the delivery roller pair of the stretching machine supplies a fiber strip with many fibers per cross-sectional unit. Only in this way can it be ensured that the fiber strip is self-supporting to a certain extent over the unsupported distance of the conveying means. This is the case, for example, in pre-spinning machines, also known as flyers. In the pre-spinning machine a relatively thick untwisted fiber sliver is produced, from which the finished yarn is finally produced in a subsequent ring spinning machine. Since such thick fiber strips are generally not provided in spinning machines of this type after the output roller pair of the drawing machine, the arrangement of the compression elements described has hitherto not been suitable for use in the compression zone of a downstream ring spinning machine. middle.

Contents of the invention

The object of the invention is to avoid the disadvantages of the prior art. The drawing machine should be improved in such a way that it can cost-effectively produce yarns of the highest quality, so-called solid yarns. Expensive pneumatics and expensive wearing parts should no longer be used here. Despite the improvement of the stretching machine, the compact design of the stretching machines known from the prior art should be maintained. It should also be particularly noted here that the improvement according to the invention can also be used in existing ring spinning machines without expensive retrofitting for this purpose.

This task is achieved in the stretching machine of the ring spinning machine with the compressor of the fiber band having the features stated in the characterizing part of claim 1 . Developments and/or advantageous embodiment variants of the invention are the subject matter of the sub-claims.

The invention proposes that a geometrically-mechanically acting compression element with compression channels is arranged in a compression zone followed by a stretching zone and that transport means are provided for supporting the fiber strip in the compression zone.

The solution of the invention avoids the disadvantages of the above-mentioned stretching machines in which the compressive elements are arranged in the main stretching zone. The problem of the compression zone following the tension zone is bypassed in that the fiber strip is supported by the compression zone of the conveying means along its entire conveying path. There is no longer tension in the compression zone. The yarn is compressed very uniformly by the compression means, which has an advantageous effect on the quality of the yarn. The solution according to the invention makes it possible to no longer use expensive pneumatic compression devices. Yarn inhomogeneities that can occur in stretching machines with compression elements arranged in the stretching zone are avoided by the arrangement according to the invention in the downstream compression zone. The resulting yarns are of good quality and are especially competitive with regard to significantly lower costs.

In a very advantageous embodiment variant of the invention, the transport means for the fiber web in the compression zone is formed by a lower cylinder, on which the output press roller and the delivery press roller are supported. In this embodiment variant the compression zone runs along the peripheral portion of the lower cylinder. The lower cylinder can have a larger diameter than known conventional stretching machines, so that the two rollers, output and delivery rollers, can easily be positioned one behind the other and the compression element can simply be arranged between these two rollers This is especially advantageous in ring spinning machines for short fiber processing. Despite its cylindrically enlarged diameter, this embodiment variant is also distinguished by a very compact construction. The stretching machine thus constituted is only slightly longer than conventional stretching machines. The fiber strips are supported by the surface of the lower cylinder along the entire longitudinal distance of the compression zone.

Advantageously the output and delivery rollers are mounted on supports, preferably spring pressed against the lower cylinder. Thus, for example, a central leaf spring is sufficient for loading one or two pressure rollers. The leaf spring is fastened to the support and bears against a stationary part of the stretching machine. The loading spring can also be mounted on a stationary part and supported on the support. For example, the stationary components are the pressure arms of the pressure rollers of the stretching machine arranged above, in particular the stretching zone against which the lower rollers or lower cylinders are pressed.

The transmission path of the fiber tape extends from the output nip line between the output press roller and the lower cylinder to the delivery nip line between the output press roller and the lower cylinder. Its length is less than one third of the length of the fibers embedded in the fiber tape. This achieves that the fiber transport in the compression zone is controlled by the fibers which are double clamped, being all fibers whose length is greater than the transport path through the compression zone. Disturbances of inhomogeneities of the fiber bands, eg due to the braking action of the compression element on the fibers, are thereby avoided.

The geometrically-mechanically acting compression element has a compression channel. The compression groove can be arranged on the lower side of the compression part facing the lower cylinder, or on the upper side of the compression part facing the pressure roller. In each case it is advantageous if the compression element rests without play on the lower cylinder in its operating position and presses against it with a predeterminable force. Uncontrolled access of fibers between the contact surface of the lower cylinder and the compression element is thereby avoided. The pressure of the compression element against the lower cylinder is produced, for example, by its own weight or by a mechanical pretensioning device or by magnetic force. Combinations of the described possibilities are also possible.

In a particularly simple embodiment variant of the stretching machine, the compression element is connected with a hook and loop strap which wraps around the circumference of the lower cylinder by more than 180°. The said buckle strip together with the compression part fixed thereon is carried when the lower cylinder rotates until the shoulder protruding from the buckle strip and/or the compression part rests on a fixed part of the stretching machine, preferably The ground support rests on the shaft giving the pressure rollers. By means of this constructional simplification, the compression element is precisely positioned relative to the clamping line between the given roller and the lower cylinder.

In order to prevent the buckle belt from rotating with the lower cylinder together with the compression part when the feeding roller is lifted and the lower cylinder rotates further, a protruding stop is provided on the buckle belt, which is in operation with the pull There is a small distance between the fixed position parts of the extension machine. If the delivery roller is lifted and thus releases the shoulders on the strap and/or the compression part, the strap with the compression part can only follow the rotating lower cylinder until the stop abuts against the tensioning machine. on fixed parts. For example, the stationary components mentioned are the guide strips of the rolling belt in the stretching machine. If the delivery roller is moved back into the working position, the pressure roller shaft presses against said shoulder and thus brings the compressor back into its working position.

For structural reasons, it turns out to be expedient if each closure strip carries two compression elements arranged on the centrally arranged closure strip.

In a very simple and cost-effective embodiment variant of the invention, the described closure strip and compression element are formed in one piece. They are preferably manufactured from plastic using batch technology, for example using injection molding.

In a further embodiment variant of the invention, the compression element rests in its operating position on the delivery pressure roller. The output pressure roller is not touched by the compression parts. The radius of the support surface of the compression part balances to a large extent the lower cylinder of the support and gives the radius of the pressure rollers. This is particularly advantageous in the bearing surface for the lower cylinder: no fibers can reach between the bearing surface of the compression part and the lower cylinder.

In order to prevent the compression element from being clamped between the delivery pressure roller and the lower cylinder, it is expedient to design the support surface of the compression element in such a way that there is a positioning surface on the delivery pressure roller which runs somewhat perpendicularly to the plane of the stretching machine. In this case, the compression element bears against the lower cylinder without play. In order to prevent any unfavorable enlargement of the compressed fibers after the compression element, the outlet of the compression element is moved as close as possible to the nip line between the pressure roller and the lower cylinder. However, in order to prevent the compression member from being clamped between the delivery pressure roller and the lower cylinder, the compression member does not extend completely to said clamping line and does not touch the delivery pressure roller there.

In an advantageous embodiment variant of the invention, the compression element can be lifted from the lower cylinder together with the delivery pressure roller, for example when the clamping wire of the delivery pressure roller should be lifted briefly, so that the yarn in the compression zone Keep turning.

In order to easily realize the liftability of the compression element, the compression element above the region forming the minimum distance between the delivery pressure roller and the delivery pressure roller is enlarged in such a way that it can be lifted together with both pressure rollers. When lifting the rollers, the compression elements are simply lifted together.

In another advantageous embodiment variant of the invention the compression element is provided with one or more permanent magnets. Said permanent magnet cooperates with the conveying means of the fiber ribbon, especially with the lower cylinder. This ensures that the compression element can press against the lower cylinder without play and is not lifted slightly even in the event of mechanical vibrations, and that no fibers can reach between the compression element and the outer surface of the lower cylinder.

For yarn uniformity, it is also expedient if the compression element is fixed axially immovably to the given pressure roller. This is done, for example, by means of shoulders or projections on the compression element which overlap the sides of the delivery press roller or delivery press roller. Said shoulder or protrusion is, for example, a plastic plug fixedly connected to the compression element. The colored material on said shoulder or protrusion can act as an indicator of the compression channel. The user can thus directly read out for which range of yarns the respective compressor is suitable.

The compression part and, if applicable, the closure strip connected thereto can be made of plastic, ceramic material or also metal, for example steel, or a mixture thereof.

In order to prevent uncontrolled penetration of the fibers between the lower cylinder and the geometrically-mechanically acting compression element, it is expedient if the lower cylinder has a circumferential surface that is formed without discontinuities, breaks or the like and is largely smooth of. Via said smooth surface, the compression element is in intimate contact with said circumferential surface and the fibers can only reach into the compression channels. The use of a smooth lower cylinder has no disadvantages for uniform stretching of the fiber strip, since the fibers emerging from the stretching zone are clamped twice in succession. For the output of the stretching zone, the fibers on the output nip line that have not yet acquired the full peripheral velocity of the lower cylinder acquire this peripheral velocity later on the given nip line, at the output of the compression zone. As a result, the moderate tension acting on those fibers whose length is greater than the length of the transport path through the compression zone favorably supports the operation of the compression element in the longitudinal direction.

When forming the circumferential surface of the lower cylinder smoothly, it has been found to be advantageous if the circumferential surface of the lower cylinder has a higher coefficient of friction for the fibers at least in the region of the run of the fiber strip. This can be achieved, for example, by chemically or electrolytically treating or coating the circumferential surface of the cylinder at least in the region of the run of the fiber strip. For example, the peripheral surface of the lower cylinder is provided with a nickel-diamond coating at least in the region of the run of the fiber strips.

In an advantageous development of the drawing machine according to the invention, a mechanically acting fiber web guide is arranged upstream of the delivery pressure rollers at the delivery end of the drawing zone. Here, the guides of the fiber strips are aligned with the stretching machine in such a way that the guide grooves of the fiber strips run approximately centrally against the compression grooves of the compression elements. A mechanical web guide at the output of the stretching zone prevents the portion of the fiber in the web fed obliquely to the inlet opening of the compression element from being transported sideways on the compression channel. Due to inhomogeneities in the stretched fiber web, non-uniform wear of the output press rollers and/or the lower cylinder, the fiber web is also subjected to lateral displacements to its prescribed position during its transport. Said lateral displacement can lead to the fact that the surrounding area of the fiber web is guided past the delivery press roller beside the compression groove. This leads to a reduction in the quality of the yarn. In contrast, the mechanical fiber web guide prevents the side region of the fiber web from being conveyed past the inlet of the compression channel by means of mechanical lateral guidance. It has been found to be advantageous here if the fiber web guide has an effective passage width which is smaller than the width of the compression channel at the inlet of the compression element. The effective traversing width of the fiber strip here is generally the width of the guide channel at or in the immediate vicinity of its outlet. The guide channel can be equipped with two side guide walls running approximately parallel. However, it can also be designed so that it tapers slightly in its width from the inlet to the outlet before the delivery pressure rollers.

In a further embodiment variant of the invention it can be provided that the fiber strip guide is arranged laterally displaceable. If necessary, the fiber ribbon guide can be moved laterally together with the compression member approximately perpendicularly to the conveying direction of the fiber ribbon. By combining the lateral displaceability of the fiber strip guide and the compressive part it is ensured that the relative alignment of these two parts with respect to each other is maintained also during lateral displacement.

The ring spinning machine according to the invention is advantageously equipped with a variant of the drawing machine according to the invention. Such a form spinning machine is able to provide cost-effective dense yarns of comparable quality to the relatively expensive dense yarns produced in prior art machines.

The stretching machine designed according to the invention is, for example, a part of a newly constructed or constructed ring spinning machine. The configuration according to the invention also makes it possible to retrofit the stretching machines of existing ring spinning machines. For this purpose, in an advantageous embodiment variant, a press roll unit can be provided which accommodates a stretching machine in place of the existing output press rolls. The pressure roller unit includes an output pressure roller and a delivery pressure roller, which are installed on a common support. A leaf spring or the like protrudes from the support, which, in the mounted state, bears against a stationary part of the stretching machine and presses the pressure roller pair against the lower cylinder. An existing stretching machine of the prior art can be supplemented in the sense of the invention with a downstream compression zone by means of a relatively simple construction of the pressure roller unit.

In this case, it is expedient if the corresponding two associated pairs of pressure rollers are mounted on the left and right of the centrally arranged support. Said mating pairs of pressure rollers are correspondingly arranged in pairs and are mounted on fixed parts of the stretching machine via brackets. Advantageously, said fixing means are pressure arms which press the pressing rollers of the stretching machine arranged at the top, in particular the stretching zone, respectively, against the lower rollers or the lower and lower cylinders.

Preferably said press roller unit is equipped with compression members permanently fixed in the gap between a mated pair of press rollers. The compression member described herein advantageously has a substantially prismatic body with a generally triangular cross-section. The radius of its support surface balances to a large extent the radius of the lower cylinder supported by the stretching machine and the giving rollers. Magnetic bodies are arranged in the body for fixing the compression element on the lower cylinder. Due to low wear, precise processability and dimensional stability, the compression part is preferably composed of a ceramic material or a plastic-ceramic mixture. However, it can also be made of plastic or metal.

In an advantageous refinement, the press roller unit also has a mechanical fiber web guide. Said fiber strip guide is, for example, permanently arranged on the output press roll. In the installed state, the fiber web guide is arranged in the stretching zone of the stretching machine. The fiber tape guide has a fiber tape guide channel arranged approximately centrally to the compression channel of the compression part and has an opening width smaller than the width of the compression channel at an inlet of the compression part . This embodiment variant of the press roller unit retains all the components necessary to form the stretching machine according to the invention and to cost-effectively produce yarns of good quality.

As a further improvement, it can also be provided in the pressure roller unit that the fiber strip guide and the compression element are arranged laterally displaceable and, if necessary, laterally displaceable together. The combination of the lateral displaceability of the fiber ribbon guide and the compression part enables a stable utilization of the fiber ribbon through the compression zone, e.g. the lateral displacement.

In a further embodiment variant of the invention it can be provided that the pressure roller unit is provided together with the lower cylinder as a set. The lower cylinder is advantageously equipped with a smooth peripheral surface which has a high coefficient of friction for the fibers at least in the region of the run of the fiber strip. This is achieved, for example, by chemically or electrolytically treating or coating the circumferential surface of the cylinder at least in the running region of the fiber strip. For example, the peripheral surface of the lower cylinder is coated with nickel-diamond at least in the region of the run of the fiber strip. A correspondingly configured lower cylinder can also be provided as a separate spare part.

Said compression part is a part based on the same idea of the invention as the stretching machine or the press roller unit of the stretching machine according to the invention and is independently protected. The compression members described herein preferably have a substantially prismatic body of generally triangular cross-section. The described substantially triangular prismatic configuration takes into account the shape of the gap between the delivery nip roll and the delivery nip roll. The radius of the support surface of the compression part largely balances the radius of the lower cylinder of the support and the delivery rollers of the stretching machine. In the body of the compression part are arranged magnets that fix the compression part on the lower cylinder. The magnets described here can protrude directly from the support surface facing the lower cylinder and form part of it. However, the magnets can also be accommodated in receiving bores in the vicinity of the support surface. For reasons of wear, and because of its favorable processability and dimensional stability, the compression part consists of a ceramic material or a plastic-ceramic mixture.

Brief introduction to the drawings

Further advantages and features of the invention emerge from the description of the exemplary embodiment of the stretching machine. Shown in the accompanying drawings:

The drawing machine of the ring spinning machine of Fig. 1 prior art;

The bottom view of the compression part of Fig. 2;

Fig. 3 has the first embodiment of the stretching machine according to the invention of the stretching zone and the compression zone;

Fig. 4 is a variant of compression means arranged in the compression zone;

Figure 5 is a frontal view of the compression part from the perspective of the incoming fiber strip;

Fig. 6 The compression zone between the two pressure rollers supported on the lower cylinder has a compression part whose compression channel is open to the lower cylinder;

Fig. 7 is similar to the configuration of Fig. 6's modification, has the compression part that its compression tank path is formed openly to the downward cylinder;

Figure 8 Compression zone, with compression parts connected to a buckle strap that wraps around the lower cylinder

Fig. 9 is installed in the pressure roller of the compression zone on the common support; And,

Fig. 10 Compression zone as shown in Fig. 6, with fiber strip guides arranged in front of output press rolls.

Detailed ways

In FIG. 1 , a drawing machine of a ring spinning machine known from the prior art is shown schematically, said drawing machine being generally designated with reference numeral 101 . The stretching machine 101 is sufficiently known from the prior art and is configured as a so-called three-cylinder stretching machine. It comprises a pull-in roller pair with a pull-in press roll 102 and a pull-in lower roll 103 for feeding the fiber ribbon F. Connected in the conveying direction of the fiber strip F is an intermediate roller pair of an intermediate press roller 104 and an intermediate lower roller 105 , through which a double belt 106 is guided. Between the pair of pull-in rollers 102 , 103 and the pair of intermediate rollers 104 , 105 a pre-stretching zone 107 of the fiber web F is delimited. At the output end of the three-cylindrical stretching machine, a pair of output rolls including an output pressure roll 108 and an output lower roll 109 is arranged. The section between the pair of intermediate rolls 104, 105 and the pair of output rolls 108, 109 constitutes the main stretching zone 110, in which the fiber strip F is stretched to the desired fineness.

The stretched fiber ribbon F exits the stretching machine 101 at the nip line A of the output roller pair 108,109. The fiber strip F is twisted into a finished yarn by means of the spinning rotation R, and forms a so-called spinning triangle at the interface with the nip line A of the output roller pair 108, 109 of the stretching machine 101. The yarns supplied by the drawing machine in the triangle are gathered together and integrated into the yarn structure. Efforts are made to keep the spinning triangle as small as possible in order to draw as many fibers as possible into the yarn and to subject all fibers to as much pretension as possible during twisting. For this reason, the stretched and widened fiber strips F are brought together again and densified before twisting into yarn. For this purpose, a compression element 111 is arranged upstream of the delivery roller pair 108 , 109 , through which compression element 111 the fiber strip F is guided. The fiber strip F is thereby compressed geometrically-mechanically by the structure of the compression element 111 .

Figure 2 shows an example of a compression member 111 having a substantially anvil-like shape. The compressing part 111 is provided with a compressing channel 112 on the side facing the fiber band in its use position, through which the fiber band F is guided. The compression channel 112 is designed with a somewhat funnel-like widening on its front side 114 facing the incoming fiber strip and tapers to the desired diameter towards the outlet on the opposite side. The outlet width of the channel determines what range of yarns the compressing part 111 is suitable for.

The disadvantages of this known arrangement have already been explained at the beginning of the text and will be explained again with reference to FIG. 1 . In the arrangement in which the compression unit 111 is provided in the main stretching zone 110 of the stretching machine 101, the fiber strip is carried out substantially simultaneously between the stretching belt 106 and the pair of output rolls 108, 109 provided in the main stretching zone 110. Tension and compression of F. As a result, the uniform stretching of the fiber strip F is disturbed. In order to create the position of the compression part 111, the distance between the nip line A of the output roller pair 108, 109 and the tension belt 106 is increased. However, this also increases the distance between which the fiber strips F are not guided. The disturbance of the uniform drawing and the increased distance over which the fiber strip F must be returned without guiding it can lead to inhomogeneities in the yarn, which affect its quality. Compression part 111 is intrusive when operating stretching machine 101 and is easily lost due to its small structure.

FIG. 3 schematically shows a stretching machine constructed according to the invention, which is generally designated with reference numeral 1 . Stretching machine 1 relates to a three-cylinder stretching machine, however modified within a decisive range. The pre-stretching zone 7 also extends from the entrance with the input press roll 2 and the input bottom roll 3 to the roll pair with the press roll 4 and the intermediate bottom roll 5 . The double belt 6 of the main stretching zone 10 is guided by an intermediate roller pair 4 , 5 . The main stretching zone 10 extends from the pair of intermediate rolls 4 , 5 to the output press roll 8 , which rests on the lower cylinder 9 . The output nip line A is defined by the contact area between the output pressure roller 8 and the lower cylinder 9 .

In contrast to known three-cylinder stretching machines, the lower cylinder 9 has a larger diameter than the usual output lower rolls. This makes it possible to arrange in the connection opening of the delivery pressure roller 8 a delivery pressure roller 15 which likewise bears against the lower cylinder 9 . The contact area between the delivery press roller 15 and the lower cylinder 9 defines the delivery nip line B. The area between the delivery nip roll 8 and the delivery press roll 15 , specifically the area between the output nip line A and the delivery line B, constitutes a compression zone 16 . Arranged in the compression zone 16 is a compression element 11 with compression channels 12 which has been modified relative to the prior art. Due to its design, the compression element 11 acts geometrically-mechanically on the widened fiber strip F guided through the compression channel 12 . The compression element 11 rests preferably without play on the lower cylinder 9 and against the delivery pressure roller 15 . The contact surface of the compression element 11 against the lower cylinder 9 is designed such that its radius is substantially equal to the radius of the supporting lower cylinder 9 . This prevents fibers from reaching between the bearing surface of the compression element 11 and the lower cylinder 9 . The longitudinal extension of the supporting surface of the lower cylinder 9 is dimensioned in such a way that it ends approximately 3 mm to 8 mm before the clamping line B is given. This prevents the compression element 11 from becoming jammed between the delivery pressure roller 15 and the lower cylinder 9 . The support surface of the compression element 11 against the delivery pressure roller 15 also balances the circumferential surface of the delivery pressure roller 15 to a large extent. In particular, the supporting surface is designed in such a way that the supporting takes place substantially perpendicularly to the stretching machine. In the region leading to the nip line, the compressor does not touch the delivery pressure roller 15 . Compression element 11 is arranged in such a way that it does not come into contact with output pressure roller 8 during normal operation. The compression element 11 has an enlarged cross-section above the region of minimum distance between the output pressure roller 8 and the delivery pressure roller 15 . This achieves that, if necessary, the compression element 11 can, for example, be briefly lifted from the lower cylinder 9 together with the delivery pressure roller 15 so that it can continue to twist R the yarn in the compression zone 16 .

In the compression zone 16 shown in FIG. 4 , the section 23 of the compression element 21 extending above the area of minimum distance between the output pressure roller 8 and the delivery pressure roller 15 is provided with a shoulder 25 or a protrusion, said shoulder 25 or the protrusion overlaps the frontal surface of the delivery pressure roller 15 and thus fixes the compression element 21 axially relative to the delivery pressure roller 15 with only a small gap. The compression zone 16 still extends from the outgoing nip line A to the outgoing nip line B, said nip line being defined by the contact area of the respective rollers 8 and 15 with the lower cylinder 9 . The fiber strip is supported by the compression zone 16 of the lower cylinder 9 along its entire course. The compression channel of the compression part 21 is marked with reference numeral 22 . It can be seen in the figure that the compression groove 22 tapers from the side facing the output pressure roller 8 along the direction of the delivery pressure roller 15 .

FIG. 5 shows a view of the concave frontal side 24 of the compression member 21 facing the incoming fiber band in the use position. On the frontal side 24 the compression channel 22 has a cross section which is significantly larger than the opposite outlet side. The upper section of the compression element 21 is again designated with reference numeral 23 . The shoulders or protrusions on the longitudinal sides of the compression element 21 are identified with 25 . A colored marking on the shoulder 25 or projection can serve as an indicator of the cross-section of the compression channel 22 . The user can thus directly read what range of yarns the compressor 21 is suitable for. Compression part 21 may be substantially made of plastic, of ceramic material or of metal, such as steel, or a mixture thereof. A permanent magnet cooperating with the lower cylinder in operation is shown at 26 . This ensures that the compression element 21 can rest without play on the lower cylinder even during mechanical pivoting and is not lifted slightly, and that fibers cannot reach between the compression element 21 and the outer surface of the lower cylinder 9 . Two permanent magnets 26 are shown in FIG. 5 . Obviously, it is also possible to incorporate only one permanent magnet or several permanent magnets in the compression part.

FIG. 6 shows the compression zone 16 with a curved transport path of the fiber strip extending from the output nip line A of the delivery press roll 8 and the lower cylinder 9 to the delivery press roll 15 and the lower column 9. Grip line B is given. The stretch zone at the front is delineated by the double belt 6 . The length 1 of the transport path AB is here less than approximately one third of the length of the fibers incorporated into the fiber strip. It can be provided that the length 1 of the transport path AB is changed by adjusting the position of the pressure roller 15 . Delineated between the two pressure rollers 8 , 15 bearing against the lower cylinder 9 is a compression element 31 , whose compression channels 32 are formed open toward the lower cylinder 9 . It can be clearly seen in this illustration that the inlet of the compression channel 32 has a larger cross-section in the vicinity of the delivery pressure roller 8 than at the junction of the compression channel 32 in the vicinity of the delivery pressure roller 15 . The compression member 31 presses against the circumferential surface of the lower cylinder 9 without gaps. This is achieved either by the own weight of the compression part 31 , by mechanical prestressing, for example by springs or the like, or by magnetic attraction between the compression part 31 and the lower cylinder 9 . Combinations of these measures may also be envisaged.

In order to prevent the uncontrolled arrival of fibers between the lower cylinder 9 and the geometrically-mechanically acting compression part 31, if the circumferential surface of the lower cylinder 9 is not discontinuous, broken or similar and is largely smooth is appropriate. With the smooth peripheral surface, the compression member 31 is in close contact with the peripheral surface and the fibers can only reach the compression channel 32 . The use of a smooth lower cylinder 9 has no disadvantages for uniform stretching of the fiber strip F, since the fibers emerging from the stretching zone can be clamped twice in succession. At the output of the stretching zone, the full peripheral speed of the lower cylinder 9 has not yet been reached, the fiber is on the clamping line A, that is to say later on the given clamping line B, i.e. at the output of the compression zone 16 Get the peripheral speed at the end. The moderate tension thus acting on those fibers whose length is greater than the length L of the transport path AB through the compression zone 16 advantageously serves to support the compression element 31 in the longitudinal direction.

When the peripheral surface 91 of the lower cylinder 9 is formed smoothly, it has been shown to be advantageous if the peripheral surface 91 of the lower cylinder 9 has a higher coefficient of friction for the fibers at least in the running region of the fiber web F. This can be achieved, for example, by chemically or electrolytically treating or coating the circumferential surface of the cylinder, at least in the region of the run of the fiber strip. For example, the peripheral surface of the lower cylinder is provided with a nickel-diamond coating at least in the region of the run of the fiber strips. The arrow marked with R still represents the spinning twist with which the stretched and recompressed fiber ribbon F is spun into the finished yarn.

FIG. 7 shows a compression zone 15 constructed similarly to that of the embodiment of FIG. 6 , the difference being the configuration of the compression element 41 . In the exemplary embodiment shown in the figure, the compressing element 41 has a compressing channel 42 which is formed open in the direction of the pressure rollers 8 , 18 . In the figure shown, the fiber band F is not guided directly over the surface of the lower cylinder but via the base surface 43 which abuts against the lower cylinder 9, so that the conveying path AB and the output clamping line A to the lower cylinder 9 are given The length between clamping lines B is slightly longer than that.

In the schematic view of FIG. 8 , a compression member whose structure corresponds, for example, to that of FIG. 7 and is therefore designated with the same reference numeral 41 is connected to a buckle strip 35 which rests elastically on the lower cylinder 9 and surrounds it. The circumferential surface 91 overlaps more than 180 degrees. Here, the closure strip 35 covers the circumferential surface 91 only in a narrow subregion. When the lower cylinder 9 rotates, the buckle belt 35 is driven to move in the direction of giving the pressure roller 15 . The shoulder 33 protruding from the buckle strip 35 bears against a stationary component, for example the axis of rotation 15 of the feed roller 15 , and prevents the compression part 41 from jamming on the feed clamping line B. At the same time, the compression element 41 is thereby precisely positioned relative to the given clamping line. As shown, shoulder 33 may be shelf-shaped; however it may also be a complete shield-shaped part. The shoulder 33 may also protrude from the compression part 41 .

If the dispensing roller 15 is lifted slightly, the shoulder 33 withdraws from engagement with the axis of rotation 17 of the dispensing roller 15 . In order to prevent the buckle strip 35 from being carried along with the connected compression part 41 when the lower cylinder is still rotating in this case, another part stop 34 which is fixed against the position is provided. For example, the described stationary component is the guide rail 61 of the double belt 6 . If the pressing roller 15 is moved back again, its axis of rotation 17 presses against the protruding contour of the shoulder 33 and moves the buckle strip 35 back together with the attached compression element 41 towards the set position. As a result, the stop 34 is also displaced by a short distance from the stationary part 61 .

As shown, the buckle strap may carry only one compression member. For structural reasons, it is advantageous if each closure strip carries only two compressive elements of the closure strip arrangement arranged centrally on both sides.

FIG. 9 shows an embodiment of the invention in which the two pressure rollers 8 , 15 are arranged on a common support 19 above the lower cylinder 9 . Said support 19 houses the two axes of rotation 17 , 18 of the two pressure rollers 8 , 15 . The support is acted upon by a spring element 63 , which is fastened to the support 19 and bears against a stationary component, such as the tension zone, preferably against the pressure arm 62 . Obviously, the spring element 63 , for example a leaf spring, can also be fixed on the pressure arm 62 and rest on the bracket 19 . The two pressing rollers 8 , 15 are simultaneously pressed to the desired degree against the lower cylinder 9 by centrally loading the carrier 19 .

FIG. 10 shows an advantageous variant of the stretching machine according to the invention. The variant shown as an example corresponds to the structure of the compression zone 16 according to FIG. 6 . The reference numbers selected in FIG. 6 are retained here. In the exemplary embodiment shown, a mechanically acting fiber ribbon guide 51 is additionally provided in the transport path of the fiber ribbon F. As shown in FIG. Said fiber strip guide 51 is also located in the stretching zone of the stretching machine and is arranged in the connection opening of the double belt directly before the output pressure roller 8 . Here, the guide 51 of the fiber band is aligned with the stretching machine in such a way that its guide channel 52 for the fiber band runs approximately centrally to the compression channel 31 . The effective width of the guide groove 52 is smaller than the entrance width of the compression groove 32 . The fiber strip guide 51 can be fastened, for example, on the shaft of the output pressure roller 8 . The fiber ribbon guide can preferably be produced from plastic, a ceramic material or a plastic-ceramic mixture, or metal. In the schematically shown exemplary embodiment, the fiber strip guide 51 has a guide channel 51 which is open in the direction of the output pressure roller 8 . In an alternative structural form, the guide groove can also be opened in the direction of the downward column 9 . Obviously, the fiber ribbon guide 51 can also be put into use in combination with a compression element whose compression channel is open to the pressure roller.

In a variant not shown, the fiber ribbon guide can be displaced laterally to the conveying direction of the fibers. In this case, the fiber ribbon guide and the compression element are coupled to one another in such a way that only a joint lateral displacement is possible. Thereby, the outlet of the guide channel of the fiber ribbon guide can remain aligned with the inlet of the compression channel even during lateral displacement.

A ring spinning machine equipped with a variant of the drawing machine of the present invention is able to provide a cost-effective compacted yarn of a quality comparable to that of the relatively expensive compacted yarn produced in prior art machines.

The stretching machines of existing ring spinning machines can be retrofitted very simply in the sense of the invention. A kind of pressing roller unit is proposed for this reason, and described pressing roller unit installs a stretching machine on the position of existing output pressing roller. The pressure roller unit includes an output pressure roller and a delivery pressure roller, which are installed on a common support. A leaf spring or the like protrudes from the support, which, in the mounted state, bears against a stationary part of the stretching machine and presses the pressure roller pair against the lower cylinder. With a press roller unit of relatively simple construction, existing stretching machines of the prior art can be supplemented in the sense of the invention with a subsequent compression zone.

In a further embodiment variant of the pressure roller unit, it has been shown to be expedient that two associated pressure roller pairs are respectively mounted on the left and right sides of the centrally arranged support. The matching press roller pairs are correspondingly arranged in pairs and installed on the fixed parts of the stretching machine through brackets.

Preferably said press roller unit has been equipped with compression elements which are permanently fixed in the gap between a pair of associated press rollers. The compression member described here advantageously has a substantially prismatic body with a substantially triangular cross-section. The radius of its support surface balances to a large extent the radius of the lower cylinder supported by the stretching machine and the giving rollers. Magnetic bodies are arranged in said prisms for fixing the compression element on the lower cylinder. Due to low wear, precise processability and dimensional stability, the compression part is preferably composed of a ceramic material or a plastic-ceramic mixture. However, it can also be made of plastic or metal. Although the compression elements described are permanently fixed in the pressure roller unit, they can be folded down when necessary to be replaced or replaced by compression elements with the desired width of the compression grooves.

In another embodiment variant of the invention, the pressure roller unit also has a mechanical fiber strip guide. Said fiber strip guide is, for example, permanently arranged in the gap between the corresponding pair of press rollers at the position of the output press rollers. In the installed state, the fiber web guide is arranged in the stretching zone of the stretching machine. The fiber ribbon guide here has a fiber ribbon guide channel which is arranged approximately centrally with respect to the compression channel of the compression part and has a width opening which is smaller than the opening of the compression channel in the compression part width. This embodiment variant of the press roller unit retains all the components necessary to form the stretching machine according to the invention and to cost-effectively produce yarns of superior quality.

In the pressure roller unit it can also be provided that the said fiber web guides are arranged laterally displaceable and can be moved together laterally if required. By combining the lateral displacement of the fiber web guide and the compression part so that when required, the targeted lateral displacement of the transport path of the fiber web through the compression zone is used, for example, to fully utilize the outlet press rollers and the delivery press rollers and / or lower cylinder. The press roll unit can be configured for the stretching machine for staple fibers or for continuous fibers. In stretching machines for filament fibers, the diameter of the lower cylinder is generally large enough to support the roller unit; while in stretching machines for staple fibers, it is necessary to be able to replace such a cylinder with a larger diameter Lower pressure roller.

When retrofitting an existing stretching machine, it may also be desirable and proposed to place the lower cylinder on the outlet of the stretching zone, so that the pressure roller unit is provided together with the lower cylinder as a set. The lower cylinder is advantageously equipped with a smooth peripheral surface which has a high coefficient of friction for the fibers at least in the region of the run of the fiber strip. This is achieved, for example, at least in the running region of the fiber strip by chemical or electrolytic treatment or coating of the circumferential surface of the cylinder. For example, the peripheral surface of the lower cylinder is coated with nickel-diamond at least in the region of the run of the fiber strip. A correspondingly configured lower cylinder can also be provided as a separate spare part.

The compression part of the stretching machine according to the invention can be provided in combination with the press roller unit or as a separate part for retrofitting or as a spare part. The compression members described herein are preferably generally prismatic with a generally triangular cross-section. The configuration of the described substantially triangular prisms takes into account the shape of the gap between the output press roll and the delivery press roll. The radius of the support surface of the compression part largely supports the radius of the lower cylinder and the given rollers of the stretching machine. In the body of the compression part are arranged magnets that fix the compression part on the lower cylinder. The magnets described here may protrude directly from the body towards the supporting surface of the lower cylinder and form part of the body. However, the magnets can also be accommodated in receiving bores in the vicinity of the support surface. For reasons of wear, and because of its favorable processability and dimensional stability, the compression part consists of a ceramic material or a plastic-ceramic mixture.

Claims (39)

1. A stretching machine of a ring spinning machine with a stretching zone (8) and a geometrically-mechanically acting compression part (11, 21, 31) with a compression channel (12, 22, 32, 42) , 41) are respectively used for stretching and stretching fiber band (F), it is characterized in that, compression part (11, 21, 31, 41) is arranged in compression zone (16), and described compression zone (16) is pulling Between the output pressure roller (8) of the extension zone (7, 10) and the delivery pressure roller (15) on the output end of the compression zone (16), there is a transmission device, and the transmission device passes through the compression zone The fiber strip (F) is supported on the entire conveying section (A, B) of (16). 2. Stretching machine according to claim 1, characterized in that the conveying means are constituted by a lower cylinder (9) on which the output press roller (8) and the delivery press roller (15) are supported. 3. The stretching machine according to claim 2, characterized in that, the output press roller (8) and the delivery press roller (15) are mounted on the support (19), and are preferably pressed down by a spring force (63). on the cylinder (9). 4. stretching machine as claimed in claim 2 or 3, is characterized in that, the transmission path of fiber band (F) extends to The nip line (9) of the press roller (15) and the lower cylinder (9) is given, and its length (1) is less than one-third of the length of the fibers embedded in the fiber band (F). 5. The stretching machine as claimed in claim 4, characterized in that the compression element (11, 21, 31, 41) rests on the lower cylinder (9) without play in its working position and with a predeterminable force Press on it. 6. The stretching machine according to claim 5, characterized in that, the pressure of the compression part (11, 21, 31, 41) on the lower cylinder (9) is passed through its own weight and/or through mechanical pre-tensioning devices and/or Produced by magnetism. 7. The stretching machine according to any one of claims 2-6, characterized in that, the compression member (31) is connected to a buckle belt (35), and the buckle belt (35) wraps the lower The circumference of cylinder (9) more than 180 degrees. 8. The stretching machine as claimed in claim 7, characterized in that a shoulder (33) protrudes from the buckle strip (35) and/or from the compression part, said shoulder (33) being in operation It rests on a stationary part of the stretching machine, preferably on the shaft ( 17 ) of the feed roller ( 15 ). 9. The stretching machine according to claim 5, characterized in that a protruding stop (34) is provided on the buckle belt (35), and the stop (34) is lifted to give Roller (15) and the lower cylinder (9) that continue to rotate abut on the part (61) that the position of drawing machine is fixed. 10. The stretching machine according to any one of claims 7-9, characterized in that each buckle belt carries two compressive parts, said compressive parts being arranged on both sides of the central buckle ring. 11. The stretching machine as claimed in one of claims 7 to 10, characterized in that the buckle strip (36) and the compression element (31) are formed in one piece. 12. Stretching machine according to any one of claims 2-11, characterized in that the compression part (11, 21) bears against the delivery pressure roller (15) in its working position, but on the contrary does not touch the output The radii of the press rollers (8), the supporting surfaces of the compression elements (11, 12) balance to a large extent the supporting lower cylinder (9) and give the radii of the press rollers (15). 13. Stretching machine according to claims 2-12, characterized in that the compression elements (11, 12) end without touching the delivery pressure roller (15) in the bearing zone formed between the outlet pressure roller (15) and Before the clamping line (B) between the lower cylinders (9). 14. Stretching machine according to one of the claims 2-13, characterized in that the compression part (11, 21) can be lifted together with the delivery pressure roller (15). 15. Stretching machine as claimed in claims 2-14, characterized in that the compression part (11, 12): Make it possible to lift together with two pressure rollers (8, 15). 16. The stretching machine according to any one of claims 2-15, characterized in that the compression part (21) is formed with a protrusion or a shoulder (25), and the said shoulder (25) or protrusion overlaps to give Out of the pressure roller (15) or the side of the output pressure roller (8). 17. The stretching machine as claimed in claim 16, characterized in that said protrusion or shoulder (25) is equipped with an indicator of the cross-section of the compression channel (22). 18. The stretching machine according to any one of claims 2-17, characterized in that the compression part (21) is provided with at least one permanent magnet (26), and the permanent magnet (26) is connected with the fiber strip (F) The transmission device cooperates. 19. The stretching machine as claimed in claim 1, characterized in that the compression elements (11, 21) are made of a ceramic material or a plastic-ceramic mixture. 20. The stretching machine as claimed in one of claims 1 to 19, characterized in that the compression elements (11, 21) and, where appropriate, the fastener strips are made of plastic. 21. The stretching machine as claimed in one of the preceding claims, characterized in that the peripheral surface (91) of the lower cylinder (9) has no discontinuities, breaks or the like and is largely smooth. 22. The stretching machine as claimed in one of the preceding claims, characterized in that the peripheral surface (91) of the lower cylinder (9) has a high coefficient of friction for the fibers at least in the running region of the fiber web (F). 23. The stretching machine as claimed in claim 22, characterized in that the peripheral surface (9) of the lower cylinder is chemically or electrolytically treated or coated at least in the running region of the fiber strip (F). 24. The stretching machine as claimed in claim 22 or 23, characterized in that the peripheral surface (91) of the lower cylinder (9) is provided with a nickel-diamond coating at least in the region where the fiber strips run. 25. The stretching machine as claimed in one of the preceding claims, characterized in that at the output end of the stretching zone, a mechanically acting fiber strip guide (51) is arranged before the output pressure roller (8), which The guide channel (52) of the fiber strip (F) is aligned approximately centrally with the compression channel (32) of the compression member (31). 26. The stretching machine according to claim 25, characterized in that the effective crossing width of the fiber ribbon guide (51) is smaller than the width of the compression channel (32) at the entrance of the compression part (31). 27. The stretching machine as claimed in claim 25 or 26, characterized in that the ribbon guide (51) can be arranged laterally displaceable and that the ribbon guide (51) can be combined with the compression part when required Together they move laterally approximately perpendicular to the conveying direction of the fiber strip (F). 28. An endless spinning machine with a stretching machine as claimed in one of the preceding claims. 29. A compression element for use in the compression zone of a stretching machine according to any one of claims 1-27, characterized in that said compression element has a substantially prismatic body with a substantially triangular cross-section, said The radii of the supporting surfaces of the compressing parts (11, 21, 31, 41) largely match the radii of the lower cylinder (9) of the support and the feeding rollers (15) of the stretching machine, and are arranged in said prism The magnetic body (26) is used to fix the compression part (21) on the lower cylinder (9). 30. Compression element according to claim 29, characterized in that the compression element (31) is connected to a buckle strip (35), and said buckle strip (35) preferably elastically overlaps over a range greater than 180° Lower cylinder (9). 31. Compression element according to claim 29, characterized in that the compression element consists of a ceramic material or a plastic-ceramic mixture. 32. A press roller unit, used in the compression zone of the stretching machine as claimed in any one of claims 1-27, characterized in that it contains output press rollers (8) and delivery press rollers (15), the The output pressure roller (8) and the delivery pressure roller (15) mentioned above are installed on the common support (19), and stretch out the leaf spring (63) or the like from the support (19), and the plate The spring (63) or the like leans against the fixed part of the stretching machine when installed and presses the given roller (15) or pair of rollers (8, 15) against the lower cylinder (9) of the stretching machine. )superior. 33. A press roller unit according to claim 32, characterized in that respectively two mating pairs of press rollers (8, 15) are mounted on the left and right sides of the centrally arranged support. Said fiber strip guide is, for example, permanently arranged on the output press roll. 34. A pressure roller unit according to claim 32 or 33, characterized in that the compression elements (11, 21, 31, 41) are permanently fixed in the gap between the associated pair of pressure rollers (8, 15), respectively. 35. The pressure roller unit as claimed in claim 34, characterized in that it is provided with a compression element (11, 21, 31, 41) as claimed in one of claims 29 to 31. 36. Press roll unit according to claim 32 or 33, characterized in that the press roll unit has mechanical fiber strip guides (51) which are permanently arranged on the corresponding pair of snatch rolls In the gap between (8,15) and output pressure roller (8) opposite, and in the stretching zone of stretching machine under the state of being installed. 37. The pressing roller unit according to claim 36, characterized in that the fiber strip guide (51) has a guide channel (52) for the fiber strip (F), said guide channel being aligned roughly centrally The compression channel (32) of the component (31) is arranged and its opening width is smaller than the width of the compression channel (32) at the inlet of the compression component (31). 38. A press roller unit as claimed in claim 37, characterized in that the fiber strip guide and the compression member are arranged laterally displaceable and are jointly laterally displaceable when required. 39. A refitted ring spinning machine, comprising a pressing roller unit and a lower cylinder (9) as claimed in one of claims 32-38, characterized in that the circumferential surface (91) of the lower cylinder (9) has no discontinuity, break Open or similar and to a large extent smooth (91), and the peripheral surface (91) of the lower cylinder (9) has a higher coefficient of friction to the fibers at least in the running region of the fiber strip (F), and The chemical or electrolytic treatment or coating is preferably performed at least in the running region of the fiber strip (F).

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