Patent Publication Number: US-6209302-B1

Title: False twist texturizing machine

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to a yarn false twist texturing machine used in the production of synthetic yarn. Such machines typically comprise a plurality of side-by-side processing points (also referred to as stations)—usually up to 216. 
     False twist texturing machines of said type comprise a plurality of processing points—usually up to 216 processing points—which are arranged adjacent to one another along the length of the machine. Each of said processing points comprises a first delivery mechanism and a second delivery mechanism. The first delivery mechanism withdraws the yarn from a supply bobbin and delivers it into a false twisting zone. The second delivery mechanism draws the yarn out of the false twisting zone and delivers it to a take-up device, the yarn speed and the stretching of the yarn being determined by the speed ratio between the second and first delivery mechanism. 
     When texturing synthetic yarns, yarn speeds are customary which demand both a suitably long heating zone and a suitably long cooling zone. In the false twisting process, the quality of the achieved crimping is influenced particularly by the yarn tensile force prevailing in the individual regions inside the false twisting zone. Thus, for example, it is known that a low yarn tensile force not yet jeopardizing the stable yarn course is required in the heating zone for achieving good crimping. On the other hand, it has also been observed that increasing the yarn tensile force, say, in the region of the cooling rail produces improved results. It would therefore be desirable to adjust a yarn tensile force in the false twisting zone which leads to good results both during the heat treatment and during cooling. 
     From EP 0 638 675 a false twist texturing machine is known which comprises a twist-stopping device in the form of a rotatable transport roller inside the false twisting zone. 
     Although this does achieve the effect that the friction force exerted by the twist-stopping device upon the yarn leads only to a slight variation of the yarn tensile force, the absolute value of the yarn tensile force in the false twisting zone is substantially dependent upon the draw ratio adjusted between the first and second delivery mechanisms. Thus, a variation of the yarn tensile force in the false twisting zone would be achievable only by varying the yarn speed. 
     An object of the invention is accordingly to provide possible ways of influencing or controlling the yarn tensile force prevailing in the false twisting zone substantially independently of the yarn speed. 
     A further object of the invention is to achieve a piecing facility which is particularly protective of the yarn, gentle yarn processing and hence higher texturing speeds. It is likewise an object of the invention to provide a false twist texturing machine, in which each processing point is easily controllable independently of the adjacent processing points. 
     SUMMARY OF THE INVENTION 
     The above and other objects and advantages of the present invention are achieved by the provision of a yarn false twisting apparatus and method which comprises a false twisting zone composed of an elongate yarn heater, an elongate cooling plate, a false twist unit, and a yarn feed system for advancing the yarn through the false twist zone. A twist stopping device is positioned upstream of the yarn heater for stopping the twist which runs back in the yarn from the false twist unit. The twist stopping device comprises a rotatable transport roller about which the yarn is at least partially wrapped, and a drive for controlling the rotation of the roller so that the yarn may be braked or advanced thereby. 
     The false twist texturing machine according to the invention and the texturing method according to the invention are notable in particular for the fact that the yarn tensile force inside the false twisting zone is variable independently of the draw ratio adjusted between the take-off delivery mechanism and the delivery mechanism disposed downstream of the false twisting zone. In such case, the false twist generated in the yarn runs back to the extent necessary for producing the crimping in the yarn. The twist-stopping device is therefore disposed immediately upstream of the heating device. The yarn tensile force in the yarn is influenced by the friction ratios between the running yarn and the peripheral surface of the driven transport roller. The transport roller may, in said case, be driven in such a way that the peripheral speed of the transport roller is lower than the yarn speed. The yarn would therefore be conveyed with a sliding friction component over the peripheral surface of the transport roller. An increase of the yarn tensile force is thereby achieved in the false twisting zone. 
     For the eventuality that the peripheral speed of the transport roller is equal to the yarn speed, a deflection of the yarn which is substantially neutral in terms of the yarn tensile force is effected by the twist-stopping device. In the false twisting zone the yarn tensile force is effective which results from the speed ratio adjusted between the take-off delivery mechanism and the second delivery mechanism. 
     In order to produce a low level of yarn tensile force in the false twisting zone, it is necessary to drive the transport roller in such a way that the peripheral speed of the peripheral surface is greater than the yarn speed. The result is a slip between the yarn and the peripheral surface of the transport roller, leading to a reduction in the yarn tension. Said method variant would also be suitable for producing a preliminary stretching in the yarn between the take-off delivery mechanism and the twist-stopping device. 
     To enable the twist torque of the yarn to be absorbed, a corresponding counter-torque has to be generated by the twist-stopping device. This is achieved in a particularly advantageous manner in that the yarn in the wrap region of the transport roller is conveyed in a zigzag manner on the peripheral surface of the transport roller. At each deflection point this produces between the yarn and the transport roller a friction which counteracts substantially only the transverse forces of the yarn. 
     The zigzag yarn running track on the peripheral surface of the transport roller may be realized in a particularly advantageous manner by means of individual yarn guide elements disposed on the periphery of the transport roller. It is thereby possible to realize any desired form of yarn excursion at right angles to the yarn running direction. The maximum excursion of the yarn is then determined by the overlap of opposing guide edges. The number of deflections is determined by the relative spacing of the yarn guide elements. 
     In a preferred development, the yarn guides take the form of rings which are mounted from both ends onto the driven transport roller carrying them. They may, in said case, between them form the yarn running track or be so shaped that the yarn running track is formed by suitable, laterally attached extensions emanating radially from the ring inner surfaces. 
     In a further preferred embodiment, the transport roller takes the form of two discs, which at their outer edges have laterally projecting yarn guide elements and are so arranged relative to one another on a drive shaft that a zigzag yarn running track is produced at a peripheral surface formed by the yarn guide elements. 
     In order to influence the wrap of the yarn around the yarn guide edges of the yarn guide elements, it is particularly advantageous when the yarn guide elements are of an adjustable design. It is therefore possible, given only a slight wrap of the peripheral surface of the transport roller, to produce in the yarn a high friction torque for absorbing the twist torque of the yarn. 
     The yarn may be pieced in a particularly gentle manner onto the transport roller by a movable yarn deflection device which is disposed directly in the yarn course upstream or downstream of the transport roller in such a way that the angle of wrap at the transport roller is variable by means of the deflection device. In said case, the angle of wrap at the transport roller may be adjusted in the range of between 0 and 360°. The yarn is preferably pieced initially with a very slight wrap onto the transport roller. It is then possible by means of the movement of the yarn deflection device for the wrap at the transport roller to be steadily increased up to the wrap required for delivery or the wrap required for the yarn course. 
     It has proved particularly advantageous when the yarn guide edges of the yarn guide elements have a radius of curvature of at least 1.5 mm. A yarn-protecting deflection for realizing the zigzag yarn course is thereby guaranteed. 
     The zigzag described by the yarn running track should, in the present case, comprise an angle of at least 100° which is open towards one or the other end of the transport roller. 
     When the peripheral surface of the transport roller is formed by yarn guide elements, given a constant drive speed of the transport roller it is possible to achieve the effect whereby the peripheral speed of the peripheral surface is variable. It is equally thereby possible for the angle of wrap at the peripheral surface of the transport roller to be influenced to a slight extent. 
     The dimensions of the twist-stopping roller according to the invention may vary within a relatively large range. However, to enable the twist torque of the yarn to be absorbed, it has been shown that it is necessary to observe a diameter of the peripheral surface of the transport roller of at least 40 mm. 
     To increase the efficiency of the transport roller, it is particularly advantageous when the transport roller at the periphery has a plurality of zigzag yarn running tracks arranged parallel next to one another. In said case, the switch from one yarn running track to the next yarn running track is guaranteed by means of a second supporting roller arranged paraxially relative to the transport roller. 
     In general it has proved advantageous to provide the yarn running track, i.e. the regions of the transport roller contacted by the yarn as well as the deflection points at the yarn guide elements with a low-wear coating or to manufacture the yarn guides from a suitable low-abrasion, e.g. ceramic material. 
     In the case of the yarns, the twist may be sufficiently braked equally by means of a galette. In said case, it is necessary for the galette to have an approach edge to enable the transverse force of the yarn to be absorbed. 
     During operation, wear phenomena arise to a greater or lesser extent at all surfaces in contact with the yarn. Said wear phenomena however also lead to a variation in the yarn tensile force of the yarn. A further possible consequence may be unstable yarn courses. It is therefore particularly advantageous when the texturing machine according to the invention is constructed with a control device which is connected to a yarn tensile force sensor and to the drive of the transport roller. Thus, the drive of the transport roller may be directly controlled in dependence upon the measured yarn tensile force. When a setpoint value of the yarn tensile force is entered in the control device, the yarn tensile force in the yarn may be permanently corrected by means of the transport roller. 
     It is recommended that the yarn tensile force sensor be disposed upstream of the heating device so that the position of the developing stretch point in the heater remains substantially stable. This additionally allows a minimum level of yarn tension to be operated in the false twisting zone. 
     Since generally the yarn tensile force in the cooling phase is higher than in the heating phase and also should not fall below a specific level, the false twist texturing machine according to the invention is preferably to be used with a yarn tensile force sensor disposed between the heating device and the cooling device, particularly in cases where the cooling device and the heating device are arranged successively in a straight yarn course, so as to rule out an increase of the yarn tensile force by deflection yarn guides. 
     In a particularly advantageous development of the texturing machine according to the invention, it is provided that the yarn is directly withdrawn from a supply bobbin by means of the transport roller. In said case, not only the yarn tensile force but also the yarn speed are determined by the transport roller and the downstream delivery mechanism. 
     The transport roller in said case is advantageously driven by means of an electric motor. Thus, each processing point is adjustable independently of the adjacent processing points. It is therefore possible to produce a substantially equally high quality of yarn at each processing point. It is however possible for a group of adjacent transport rollers to be driven jointly by means of one drive. In said case, the transport rollers are connected to one another by a drive through-shaft which is driven by means of a motor. 
     It is known, e.g. from DE 33 24 243, for the delivery mechanisms of the processing points to be driven by a drive motor, the first delivery mechanisms and the second delivery mechanisms being drive-connected to one another. The delivery mechanisms of adjacent processing points are formed, in said case, by drive through-shafts. 
     Given such an arrangement, the lap formations which arise at the delivery mechanisms in the event of a yarn breakage are removable either only by disconnecting the entire machine or only with extreme difficulty while the drive shafts are in operation. Furthermore, when re-piecing a yarn at a processing point the problem arises that the yarn has to be pieced onto delivery mechanisms operating at the high delivery speed necessary for processing. 
     In air bulking machines for manufacturing loop yarns it is customary for the delivery mechanisms to be driven by individual drives, in the manner known from DE 36 23 370. Such machines have no false twisting zone, with the result that a relatively short yarn course may be realized between the supply bobbin and the take-up device. The delivery mechanisms in said case are combined into modules disposed within reach of the attendant and having one or more drives. The galettes or apron delivery mechanisms used in said case do however also have the drawback that a broken yarn leads to a lap formation which is very difficult to remove. 
     The particularly preferred development of the invention provides a false twist texturing machine which is notable for the fact that the first delivery mechanism is formed by a transport roller. Here, the required transport speed is transmitted to the yarn by friction forces. For said purpose, the yarn is wrapped partially in a peripheral direction around the transport roller, the yarn being deflected back and forth at right angles to its running direction so as to produce a zigzag yarn running track at the periphery of the transport roller. By virtue of said zigzag yarn running track at the periphery the friction forces at the yarn are increased to such an extent that sliding of the yarn on the peripheral surface is prevented. A further result of the zigzag yarn running track is that only a tensioned yarn is applied onto the peripheral surface of the transport roller since the slippage resistance at the deflection point of the yarn running track has to be overcome. In the event of a yarn breakage, therefore, no tight lap will form on the peripheral surface of the transport roller. The yarn will wind on at the periphery outside of the yarn running track and will therefore be easily removable. 
     The transport rollers are drivable in each case independently of one another so that each processing point is individually controllable. Thus, in a particularly advantageous manner so-called sympathetic yarn breakages may be avoided. A sympathetic yarn breakage occurs when the yarn breakage at one processing point leads to one or more yarn breakages at adjacent processing points. With the texturing machine according to the invention, a high operational reliability and minimum yarn spoilage are therefore achieved. 
     Even when setting up a false twist texturing machine according to the invention, alignment errors at the base do not result in any kind of influencing of the delivery mechanisms. 
     In a preferred embodiment, the transport rollers may be coupled and/or are detachably connected to the respective drives. Thus, in the event of lap formation, the transport roller may easily be removed from the processing point and replaced by a new transport roller. Non-productive periods are therefore considerably shortened. 
     The drives of the transport rollers preferably take the form of electric motors which are controllable by means of individual converters or group converters. 
     In a development of the invention, the transport rollers are driven in each case by a drive unit combined with an eddy-current brake. By virtue of such an arrangement the control outlay for the drive may be reduced. 
     In a further particularly advantageous embodiment of the texturing machine according to the invention, the transport roller may be attended by means of a piecing apparatus. It is therefore possible to realize short yarn courses in the machine. The transport rollers may be positioned in the machine at points which the attendant may reach only with auxiliary devices. A further advantage arises from the fact that the yarn may be conveyed with the minimum of deflections, enabling gentle treatment of the yarn with few friction points. 
     From EP 0 641 877 A2 a false twist texturing machine is known which comprises a winding frame, a processing frame and a creel frame. An attending aisle is formed between the winding frame and the processing frame for manually piecing each yarn in a free-running manner onto the delivery mechanisms and other treatment devices. Said construction leads to a complicated yarn course with a plurality of deflection points in the yarn course between the creel frame and the processing frame. 
     The particularly advantageous construction of the invention provides a false twist texturing machine which has the first delivery mechanism disposed immediately upstream of the inlet of the first heater and which has the heater and the cooling device disposed in a flush manner. The effect achieved by said arrangement is that the yarn is exposed to very little friction as it runs through the heater and the cooling rail. By means of the delivery mechanism a defined transport speed is imparted to the yarn. By virtue of the arrangement according to the invention it could additionally be possible to dispense with the use of an additional twist-stopping device upstream of the heater. The yarn twist generated by the yarn twister in the yarn course downstream of the cooling rail would continue only as far as the first delivery mechanism. In the delivery mechanism a suspension of the twist is then effected as a result of a wrap-generated friction torque or clamping action at the yarn. The twist-stopping roller therefore delimits the false twisting zone. The false twist texturing machine according to the invention is also particularly notable for its low overall height because the plane, in which the heater and the cooling device are disposed, extends horizontally or with a slight inclination relative to the horizontal. 
     According to the invention, the first delivery mechanism is attended by a piecing apparatus. The effect thereby achieved is that the yarn at the start of processing may be reliably pieced by an attendant or, in the event of lap formation, said laps may be removed. In said case, it is particularly advantageous when the piecing apparatus is operable from the attending aisle. It is thereby guaranteed that, at the start of processing, piecing of the yarn into the delivery mechanisms and the individual treatment devices may be carried out manually by an attendant. 
     The piecing apparatus in said case may comprise two portions, the piecing apparatus in the first portion being vertically displaceable in order, for example, to transfer the yarn from the attending position to the necessary working height for piecing. In the second portion the piecing apparatus is horizontally displaceable so that, for example, the yarn may be inserted into a guide roller disposed above the bobbin creel and then the yarn is conveyed to the transport roller. 
     An advantageous development of the false twist texturing machine has the advantage that the attending aisle and the doffing aisle for removing the textured yarn bobbins are separate from one another. As a result, the finished bobbins may be removed at any time by a removal device without the attendant being impeded thereby. The yarn is moreover conveyed immediately from the creel frame along a short route directly to the heater inlet. During said process, the yarn is conveyed advantageously only via one guide roller. 
     A particularly advantageous embodiment provides that the first delivery mechanism is firmly connected to a height-adjustable piecing arm of the piecing apparatus. Thus, the first delivery mechanism may be displaced back and forth between an attending position and an operating position. In the attending position, which is reachable by the attendant, the yarn is pieced manually onto the first delivery mechanism. The delivery mechanism is then brought by the piecing arm into the required operating position for the texturing process. In said case, the piecing apparatus could advantageously simultaneously effect piecing of the yarn onto the first heater in the manner known, for example, from U.S. Pat. No. RE 30159. 
     In an advantageous development of the false twist texturing machine according to the invention, the transport roller is firmly connected to a height-adjustable piecing arm of the piecing apparatus and is displaced by means of the height adjustable piecing arm between an attending position and an operating position. As a result, the yarn at the start of processing may be pieced by an attendant, thereby increasing piecing reliability. Furthermore, in the event of lap formation at the transport roller, an exchange of the transport roller or removal of the yarn residue may be carried out in the attending position by the attendant without auxiliary means. 
     A particularly preferred development of the invention results in extreme flexibility of the respective processing point. Thus, the delivery mechanisms of a processing point may be individually adjusted. In addition, in the event of yarn breakage upstream of the take-up device, the laps are also easily removable from the delivery mechanism. 
     The drives of the transport rollers are, in said case, connected to one another by a control device so that the delivery speeds of the delivery mechanisms of a processing point remain set at the speed ratio required for stretching of the yarn. It is therefore also possible to realize any desired speed ratio between the delivery mechanisms. 
     The control device is connected to a yarn tensile force sensor which is disposed inside the false twisting zone. Thus, the yarn tensile force required for the process may be influenced by means of the transport rollers. This is particularly advantageous when, after an extended period of operation, wear phenomena at the yarn-guiding parts increase the yarn tensile force required for the process up to an unacceptable level. It also allows the special running of processes with a very low level of yarn tensile force. In the event of yarn breakage, an advantageous disconnection of the transport roller may also be effected by said means. 
     A development of the invention provides that the control devices of a processing point are connected to a machine control unit. The possibility is therefore created of effecting a collective variation of the speed of the delivery mechanisms which is initiated via the machine control unit. Said arrangement is advantageous when, for example, the yarn speed is to be increased in the processing point. For said purpose, a collective adjustment of the processing point is effected by the machine control unit. However, the possibility also exists, e.g. for switching the delivery mechanisms over from a piecing speed to an operating speed, of the machine control unit preselecting a timing function for the control device. The timing function controls the switchover of the speeds of the delivery mechanisms in such a way that prevents the occurrence of undesirable yarn tension peaks. 
     In a particularly preferred development of the invention, the control device of a processing point is connected to an energy store which, in the event of a power failure, enables a controlled braking of the drives inside the processing point. It is thereby possible to prevent a power failure leading to an uncontrolled discontinuation of the process, which causes a yarn breakage. 
     In order at the start of the process to prevent yarn tension peaks from being generated in the yarn during piecing, it is particularly advantageous when the transport rollers of a processing point during piecing have substantially the same transport speed. Reliable piecing is thereby effected. 
     The yarn guide at the transport roller may be designed in such a way that angles of wrap greater than 180° may be realized at the transport roller without substantially increasing the yarn tensile force in the yarn. The yarn may be deflected by such transport rollers substantially without affecting the yarn tensile force. This is particularly advantageous for realizing compact machine-mounted accessories. It is therefore possible to combine machine components into individual modules. 
     A particularly advantageous development of the invention is constructed, downstream of the second delivery mechanism, with a second heater and a third delivery mechanism in the form of a transport roller. The false twist texturing machine is then particularly suitable for texturing polyester yarn. The heat aftertreatment of the yarn is effected in said case in the second heater, the yarn tensile force depending upon the speed ratio of the transport rollers upstream and downstream of the heater. 
     In the present case, the set heater is disposed downstream of the second delivery mechanism in the processing frame. A third delivery mechanism, which delivers the yarn for take-up, is disposed on the winding frame. 
     A further preferred embodiment of the false twist texturing machine has individual drives for each unit of a processing point. Extreme flexibility in terms of the processing of yarn and the machine arrangement is thereby achieved. In the take-up device, the reciprocating device and the friction roller are driven in each case by individual drives, preferably converter-controlled electric motors. The false twister is likewise equipped with an individual electric drive. 
     In the case of the refinement of the individual drives of the take-up device, the embodiment in which the drive of the friction roller is integrated axially in the friction roller is particularly advantageous. It is thereby possible to produce a particularly compact take-up unit. 
     Before the yarn is conveyed to the take-up device it is usually provided with a coating of preparing agent. Such projection devices preferably take the form of roller preparation devices. In the present case, the projection agent is conveyed from a bath onto the yarn by means of a roller. For increased flexibility of the processing point, it is particularly advantageous when said roller is driven by means of a roller motor. The roller motor in the present case is driven independently of the adjacent processing point. 
     In a particularly preferred embodiment of the invention, a yarn tensioning device is disposed in the yarn course upstream of the transport roller. Said yarn tensioning device is adjustable in such a way as to generate a defined preliminary tension. The yarn tensioning device in the present case may be advantageously realized by a plurality of yarn guides partially wrapped around by the yarn, one of the yarn guides being adjustable in order to vary the wrap. 
     The false twist texturing machine according to the invention and the method according to the invention are particularly notable for their extreme flexibility in terms of the manufacture of textured yarns. It is possible to process both fine-denier polyamide yarns and polyester yarns of a very high titre by suitably adjusting the yarn tensile force in the false twisting zone. 
     A piecing up method in accordance with the invention is particularly suitable for piecing the yarn at high yarn speeds. Here, for avoiding high yarn tension peaks, there is the possibility of coordinating the piecing speeds of the delivery mechanisms. The first delivery mechanism and the second delivery mechanism may therefore be operated at the same speed. 
     The switchover of the delivery mechanisms from the piecing speed to the operating speed is advantageously effected in accordance with a preselected timing function. It is thereby possible to effect a collective adjustment of the delivery mechanisms. The objective is however to preselect the timing function for controlling the delivery mechanisms in such a way that the draw ratio defined by the speed difference of adjacent delivery mechanisms is adjusted only upon attainment of the operating speed. By said means, unacceptable yarn tension peaks are avoided upon start-up of the machine, once the yarn has been inserted into each unit. 
     The false twist texturing machine according to the invention is also preferably designed as a double machine. In said case, the two machine halves are so positioned relative to one another that the processing frames lie immediately opposite one another. As a result, the electric drive components for the false twisting units and for the second delivery mechanism may be combined in a common drive cabinet. 
     The machine according to the invention enables a particularly gentle texturing of yarns at high texturing speeds. Because of the substantially rectilinear course of the yarn between the creel frame and the processing frame, with the yarn spanning the take-up frame, a low overall height of the machine is realized. Despite said low overall height, the false twist texturing machine is equipped with a heating and cooling section which is also suitable for high speeds of even coarse polyester yarns. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Several embodiments are described in detail below with reference to the accompanying drawings. 
     The drawings show: 
     FIGS. 1 and 2 the diagrammatic representation of a false twist texturing machine according to the invention with closed-loop control of the yarn tensile force in the false twisting zone; 
     FIG. 3 the diagrammatic representation of a further embodiment of a false twist texturing machine; 
     FIGS. 4 to  6  a twist-stopping device in the form of a transport roller; 
     FIGS. 7 and 8 further embodiments of a twist-stopping roller; 
     FIG. 9 a diagrammatic view of a further embodiment of a false twist texturing machine according to the invention; 
     FIG. 10 a diagrammatic view of a double machine; 
     FIG. 11 a diagrammatic view of a further embodiment of the false twist texturing machine according to the invention; 
     FIGS. 12 and 13 further embodiments of the false twist texturing machine according to the invention with individual drives; 
     FIG. 14 a further embodiment of a machine control unit of a texturing machine from FIG. 11; 
     FIG. 15 a delivery mechanism with yarn deflection device; 
     FIG. 16 a further embodiment of a drive for a delivery mechanism; 
     FIG. 17 a further embodiment of a false twist texturing machine according to the invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     In the following embodiments of the false twist texturing machine according to the invention, structural parts of identical function are denoted by identical reference characters. 
     The following description applies to the false twist texturing machine according to FIGS. 1 to  3 . Where differences occur, this is specifically mentioned in the description. 
     The false twist texturing machine comprises in longitudinal direction—in the drawings, the drawing plane equals the transverse plane—a plurality of processing points, in each case one yarn per processing point being processed. Since the take-up devices take up a width of three processing points, there are in each case three winding points disposed in a column one above the other on the take-up device  9 . Accordingly, there are likewise in each case three supply bobbins  7  disposed one above the other at a bobbin creel  1 . 
     Each processing point has a supply bobbin  7 , on which a thermoplastic yarn  4  is wound. The yarn  4  is withdrawn via a top yarn guide  12  under a specific tension by the first delivery mechanism  13 . 
     The yarn  4  is then deflected by means of a guide roller  11  towards the twist-stopping device  65  and travels through an elongate heating device  18 . In so doing, the yarn is heated up to a specific temperature. The heater takes the form of a high-temperature heater, in which the heating surface temperature is above 300° C. Such a heater is known, for example, from U.S. Pat. No. 5,148,666. To said extent, reference is made to said publication. 
     Situated downstream of the heating device  18  is a cooling device  19 . The cooling device  19  takes the form of an elongate cooling rail. Between the heating device  18  and the cooling device  19  the yarn is conveyed over a guide roller  11  so that the heating device  18  and the cooling device  19  are arranged in a V shape relative to one another. 
     The texturing machine according to the invention is however not restricted to such an arrangement but also permits any other association between the heating device and the cooling device, e.g. to achieve a straight yarn course, in the manner later described. 
     Situated downstream of the cooling device  19  is a diagrammatically illustrated false twisting unit  20 . Said false twisting unit  20  may take the form of a friction disc unit of the type described, for example, in U.S. Pat. No. 5,794,429. 
     Downstream of the false twisting unit  20 , a second further delivery mechanism  21  is used to draw the yarn  4  through both the heating device  18  and the cooling device  19 . Situated in yarn running direction downstream of the second delivery mechanism  21  is a set heater  22 . Said set heater may take the form of a curved heating tube which is surrounded by a heating jacket, the heating tube being heated up to a specific temperature from the outside using steam. The set heater  22  could however alternatively, like the first heating device  18 , take the form of a high-temperature heater. 
     The yarn  4  in the present case is drawn by a further third delivery mechanism  23  out of the set heater and delivered to a take-up device  9  In the take-up device  9 , the yarn  4  is wound onto a take-up bobbin  25  which is supported by a conventional package cradle  66  and driven by a friction roller  24 . Situated upstream of the friction roller  24  is a reciprocating device, by means of which the yarn is conveyed back and forth at the take-up bobbin  25  and wound as a cross winding onto said take-up bobbin. 
     The delivery mechanisms  13 ,  21  and  23  are driven separately and in accordance with processing requirements at different delivery speeds which are in a fixed ratio relative to one another. Said drive may be effected in a known manner with the aid of drive through-shafts, in which case the drive shafts of the three delivery mechanism groups  13 ,  21  and  23  are firmly coupled to one another—e.g. by means of a quick-change gearing. 
     In the embodiments of FIGS. 1 to  3 , the twist-stopping devices  65  each take the form of a transport roller  30 , around which the yarn  4  is partially wrapped. The yarn  4  is conveyed in a zigzag yarn running track on the peripheral surface of the transport roller  30 , as will be described in more detail below. The transport roller  30  is coupled to a drive  46 . 
     In the embodiment in FIG. 1, the drive  46  of the twist-stopping roller  30  is connected to a control device  49 . Between the twist-stopping roller  30  and the heating device  18  a yarn tensile force sensor  63  is disposed in the yarn course. The yarn tensile force sensor  63  is connected to the control device  49 . In the embodiment illustrated in FIG. 1, the yarn  4  is withdrawn from the supply bobbin  7  by the delivery mechanism  13  and delivered into the false twisting zone. The false twist is introduced into the yarn  4  by the false twisting unit  20 . The false twist thus produced runs back counter to the yarn running direction as far as the twist-stopping roller  30 . Thus, the yarn is conveyed in the false-twisted state through the heating device  18  and the cooling device  19 . The yarn in the twisted state is stretched and set in the heating device  18 , which results in a strong imprinting of the twist and hence in a good crimping result in the yarn. By means of the yarn tensile force sensor  63  the yarn tensile force immediately upstream of the inlet of the heating device  18  is measured. Said measured value is supplied to the control device  49  which, if it determines a deviation from a setpoint value, controls the drive motor  46  of the twist-stopping roller accordingly so that the desired yarn tensile force is adjusted. With said arrangement it is possible to run processes which are executed with an extremely low yarn tensile force. The yarn is drawn by the second delivery mechanism  21  out of the false twisting zone and then conveyed into an aftertreatment zone, e.g. for shrink-resistant treatment of the yarn, to the set heater  22 . Here, it could also be advantageous to install an additional delivery mechanism upstream of the inlet of the set heater to enable an adjustment of the delivery speeds (lagging) in the after-treatment zone which is independent of the delivery speed adjustment of the delivery mechanisms of the false twisting zone. Between the second delivery mechanism and the additional delivery mechanism upstream of the set heater a tangle nozzle may advantageously be disposed in the yarn course to achieve an opening of the filaments for improved shrink-resistant treatment. After the heat aftertreatment, the yarn is wound into a cross-wound bobbin  25  at the take-up device  9 . 
     The embodiment of the texturing machine according to the invention illustrated in FIG. 2, compared to the embodiment of FIG. 1, presents a further possible way of measuring the yarn tensile force in the false twisting zone. Here, the yarn tensile force sensor  63  is positioned between the heating device  18  and the cooling device  19 . Said variant is particularly advantageous when a preselected yarn tensile force should be adjusted for cooling the yarn. 
     The embodiment according to FIG. 3 shows a preferred form of construction, in which the twist-stopping roller  30  withdraws the yarn  4  directly from the supply bobbin  7 . Here, the twist-stopping device acts as the first delivery mechanism  13 . The yarn speed in the false twisting zone is adjusted by the delivery speed of the transport roller  30  and the second delivery mechanism  21 . In order to obtain a specific initial force for generating the friction forces at the transport roller  30 , a yarn tensioning device  50  might be disposed between the top yarn guide  12  and the transport roller  30 . Said embodiment is notable for a particularly simple construction and processing sequence. 
     FIGS. 4 to  6  show a first embodiment of a twist-stopping roller or transport roller which could be used, for example, in the embodiments of the false twist texturing machine according to the invention of FIGS. 1 to  3 . The twist-stopping device comprises a transport roller  30  which has at its periphery a zigzag yarn running track  31 . The zigzag yarn running track  31  is formed by placing on the peripheral surface  36  of the transport roller a plurality of yarn guides  37  and  38  alternating in a peripheral direction and uniformly spaced apart (see FIG.  5 ). The yarn guides  37  have their guide edges  39  associated with the end  40  of the transport roller  30 . The yarn guides  38  have their guide edges  45  associated with the opposite end  41 . The guide edges  39  and  45  of adjacent yarn guides are aligned offset relative to the center plane  43  in an overlapping manner so that a yarn wrapped around the guide edges  39  and  45  adopts a zigzag yarn course at the periphery of the transport roller  30 . As FIG. 5 reveals, the guide edges  39  and  45  of the adjacent yarn guides are fashioned in such a way as to form a notch  44 , in which the approaching yarn  4  is caught and may slide along the respective guide edges  39  or  45  onto the peripheral surface  36 . The multiple wrapping around the yarn guides  37  and  38  therefore generates a friction force which absorbs the twist torque of the yarn. The transport roller  30  is firmly coupled to a drive shaft  42  which is driven by a drive (not shown here). The yarn tensile force in the yarn is influenced by the sliding or static friction between the yarn  4  and the peripheral surface  36  as well as by the sliding or static friction between the yarn  4  and the yarn guide elements  37  and  38 . As a further parameter for influencing the yarn tensile force, the angle of wrap between the yarn inlet and the yarn outlet of the transport roller  30  may be preselected. The yarn guide elements  37  and  38  are preferably made of ceramic materials. 
     The transport roller is mounted onto the end of a drive shaft  42 . In the present case, the transport roller  30  is coupled by means of a keyed plug-in connection firmly to the drive shaft  42 . The plug-in connection between the transport roller  30  and the drive shaft  42  is secured by means of a retaining ring  47 . It is therefore possible to exchange the transport roller  30  with little effort. 
     It should be pointed out at this stage that, in the case of the delivery mechanism according to the invention, the friction force required for delivery might also be generated by clamping of the yarn. 
     It is equally possible for the alternating arrangement of yarn guide elements  37  and  38  to be non-uniform so that, for example, the wrap in sub-regions of the transport roller is halved by means of two successive guide elements of a disc per guide element. 
     The design of the transport rollers  30  is effected in such a way that the yarn tensile forces which have to be applied in a processing stage are reliably transmitted and a slip between yarn  4  and transport roller  30  is avoided in order to create, from processing point to processing point, identical delivery conditions as a prerequisite for a good product result. In particular, this is also achieved in that the yarn running track  31  extends along a geometrically clearly defined diameter so as to produce, from delivery mechanism to delivery mechanism, precisely reproducible speed and draw ratios. As parameters, it is possible in said case to vary the roller diameter, the number and hence the pitch of the yarn guides on the roller periphery, the roller width and further, by means of the selected material of the guide surfaces and by means of the arrangement of the transport rollers in the yarn course, the angle of wrap between yarn inlet and yarn outlet. It is possible, independently of the yarn material (titre, residual stretch), to adjust the yarn delivery speeds and the yarn intake tensions individually at each processing point. Said adjustability is particularly advantageous also at the start of processing for yarn piecing in order to avoid yarn tension peaks in the yarn. 
     A further example of a twist-stopping roller is shown in FIG.  7 . Here, the twist-stopping roller is formed by two discs  72  and  73  which are fastened coaxially with one another to a drive shaft  71 . The discs, at their sides directed towards one another, have the yarn guide elements  37  and  38  at the outside edge. The yarn guide elements  37  each have a guide edge  39 , which terminates in a guide surface  69  extending in a peripheral direction. The yarn guide elements  38  lying opposite in an offset manner have the yarn guide edges  45 , which likewise terminate in a guide surface  75  extending in a peripheral direction. The guide surfaces  69  and  75  are situated on a diameter and therefore form a circumferential support surface for the yarn. The yarn guide elements  37  are coupled by a guide  70  to the disc  72 . The yarn guide elements  38  are likewise coupled by a guide  74  to the disc  73 . By radially adjusting the yarn guide elements it is therefore possible to vary the diameter of the yarn support surface formed by the guide surfaces  69  and  75 . Furthermore, the discs  72  and  73  are displaceable relative to one another so that the yarn guide edges  39  and  45  overlap one another to a greater or lesser extent. By said means, an increase of the yarn wrap at the yarn guide elements  37  and  38  is achieved. Thus, in addition to the variable rotational speed, there are further parameters for the twist-stopping device which are available for influencing the yarn tensile force of the yarn. FIG. 8 shows a further embodiment of a twist-stopping roller. Here, the yarn guide elements  37  are connected to one another by a circumferential ring. The yarn guide elements  38  are likewise coupled to one another by a circumferential ring. The two annular yarn guide elements are, in said case, arranged with the projecting guide edges  39  and  45  offset relative to one another in such a way that they engage one into the other. A notch  44  is thereby formed, in which an approaching yarn slides. By virtue of the deflection by means of the guide edges  39  and  45  the yarn is therefore forced into a zigzag yarn running track. The yarn, in said case, lies on the periphery-shaped guide surface  69 . The wrapping of the yarn around the guide edges  39  and  45  may be effected in the present case by axially displacing the yarn guide elements  38  by means of an adjusting device  68 . The yarn guide elements  38  in the present case are connected by a guide  67  to the transport roller  30 . The transport roller  30  is in turn mounted onto a drive shaft  71 . For securing the connection between the transport roller  30  and the drive shaft  71 , a retaining ring  47  is attached to the shaft end of the drive shaft  71 . 
     The following description applies to the embodiments of the false twist texturing machine according to FIGS. 9 and 10. 
     The false twist texturing machine comprises a creel frame  2 , a processing frame  3  and a winding frame  1 . An attending aisle  5  is formed between the processing frame  3  and the winding frame  1 . At the opposite side of the winding frame  1  to the attending aisle  5  the creel frame  2  is disposed at a distance from the winding frame  1 . Thus, a doffing aisle  6  is formed between the winding frame  1  and the creel frame  2 . 
     The false twist texturing machine comprises in longitudinal direction—in the drawings, the drawing plane equals the transverse plane—a plurality of processing points for, in each case, one yarn per processing point. The take-up devices take up a width of three processing points. For said reason, there are in each case three take-up devices  9 —more details of which are given later—arranged one above the other in a column in the winding frame  1 . 
     Each processing point has a supply bobbin  7 , on which a thermoplastic yarn  4  is wound. The yarn  4  is withdrawn via a top yarn guide  12  and a guide roller  11  or a yarn guide under a specific tension by the first delivery mechanism  13 . In the embodiment according to FIGS. 9 and 10, the yarn is conveyed between the creel frame  2  and the first delivery mechanism  13  without tubular guidance. It is however possible in said case also to use tubular guides for transporting the yarn from the supply bobbin to the attending aisle. 
     Disposed in the yarn course upstream of the first delivery mechanism  13  is a yarn cutter  14 . The yarn cutter  14  may be used to sever the yarn in the event of faults arising in the processing run between the first delivery mechanism  13  and the take-up device. 
     The first delivery mechanism here takes the form of a transport roller  30  which has, at its periphery, a zigzag yarn running groove  31  of the type subsequently indicated in the description relating to FIGS. 3 to  6 . In the present case, the transport roller  30  is simultaneously used as a twist-stopping device for stopping the twist generated in the yarn by false twisting unit  20 . One transport roller  30  is associated with each processing point. The transport roller  30  is driven by means of an individual electric drive (not shown here). The transport roller  30  and the drive are connected by a holding device  15  to a piecing arm  16 . Fastened to said piecing arm there is likewise a yarn cutter  14  disposed in the yarn course upstream of the transport roller  30 . The piecing arm  16  is connected to a slide  32 . The slide  32  is moved by a linear drive along the guide  33  between an operating position  34 —as shown in FIG.  9 —and an attending position  35 . Thus, at the start of processing the yarn may be pieced manually by an attendant onto the transport roller  30 . The transport roller  30  is then moved into its operating position  34  by means of the piecing apparatus  17 . 
     In the present case there is however also the possibility of the drive, which drives e.g. a group of transport rollers, being fastened in a stationary manner to the machine frame. The transport rollers might then, in their respective operating position, be couplable to the drive. 
     It is however also possible for the first delivery mechanism to be disposed in a stationary manner in the machine and driven, for example, by a central drive acting for a plurality of processing points. At the start of processing, the yarn is therefore conveyed from the attending position to the delivery mechanism by means of a yarn guide which is movable on the piecing apparatus. Piecing of the yarn is then effected at the delivery mechanism. 
     It should be expressly mentioned that the first delivery mechanism may alternatively be formed by other yarn delivery means such as, for example, delivery shafts or galettes. 
     Situated in yarn running direction downstream of the first delivery mechanism  13  is a first elongate heater  18 , through which the yarn  4  travels, the yarn being heated up to a specific temperature. The heater might take the form of a high-temperature heater, in which the heating surface temperature is above 300° C. 
     Situated downstream of the heater  18  is a cooling rail  19 . In the present case, the heater  18  and the cooling rail  19  are disposed in a flush manner downstream of one another so as to produce a substantially straight yarn course. Situated downstream of the cooling rail  19  is a diagrammatically illustrated false twisting unit  20 . 
     Downstream of the false twisting unit  20  a second, further delivery mechanism  21  is used to draw the yarn  4  through both the heater  18  and the cooling rail  19 . Situated in yarn running direction downstream of the second delivery mechanism  21  is a second heater  22  (set heater). Said set heater may take the form of a curved heating tube surrounded by a heating jacket, the heating tube being heated up to a specific temperature from the outside using steam. The set heater  19  might, like the first heater  18 , also take the form of a high-temperature heater. 
     Seamlessly adjoining the second heater  22  in yarn running direction is a levelling tube  29  of the type known from U.S. Pat. No. 5,431,002. The effect thereby achieved is that the yarn  4  conveys the atmosphere of the heater  22  into the levelling tube  29 . The yarn guide  28  is situated in the bend between the heater  22  and the levelling tube  29 . 
     Situated at the outlet end of the levelling tube  29  is a further, third delivery mechanism  23 . Situated upstream or downstream thereof is a preparation device (not shown) which repairs the yarn  4  before the yarn runs into a take-up device  9 . In the take-up device  9  the yarn  4  is wound onto a take-up bobbin  25 , which is driven at the periphery by a friction roller  24 . Situated upstream of the friction roller  24  is a reciprocating device  26 , by means of which the yarn  4  is conveyed back and forth at the take-up bobbin  25  and wound on the latter as a cross winding. 
     In the false twist texturing machines according to the invention it is possible to dispose below the second heater  22  instead of the levelling tube  29  first, instead of the yarn guide  28 , the third delivery mechanism  23  and then provide a tangle nozzle followed by a further delivery mechanism. It is thereby possible to swirl the treated yarn with an adjustable yarn tensile force in the tangle nozzle by blowing air onto the yarn and to intermingle the filaments. 
     Situated above the levelling tube  29  is a platform  27  which is used as an attending aisle  5 . The attending aisle  5  is formed between the processing frame  3  and the winding frame  1 . Disposed above the attending aisle  5  is the cooling rail  19  which is supported substantially on the processing frame  3 . Disposed in the processing frame in accordance with the yarn course are the false twisting unit  20 , the second delivery mechanism  21  and the second heater  22 . The processing frame is therefore notable for the fact that it contains only the machine parts which are used for the yarn treatment. 
     In the upper region of the winding frame  1 , at the side remote from the attending aisle  5 , the first delivery mechanism  13  is disposed immediately upstream of the inlet of the first heater  18 . The first heater  18  is in turn supported on the winding frame  1 . In accordance with the yarn course, the third delivery mechanism  23  is fastened in the winding frame  1  to the bottom end of the winding frame. The take-up devices  9  are moreover disposed in the winding frame  3 . 
     The take-up device  9  comprises a bobbin store  8  which is used to receive the full package once a full take-up bobbin  25  has been produced at the take-up device. For removal of the full package  25 , the spindle support is swivelled and the full package deposited onto a roll-off track. The roll-off track is part of the bobbin store  8 . The full package  25  waits on the roll-off track until it is carried away. For said reason, the roll-off track of the bobbin store  8  is disposed at the side of the winding frame  1  which is adjacent to the doffing aisle  6  and remote from the attending aisle  5 . The doffing aisle  6  extends along the winding frame  1  and is formed between the creel frame  2  and the winding frame  1 . It is used for removal of the full packages waiting at the bobbin store  8 . There is further associated with each take-up device  9  a tube supply device  10  which is not described in any greater detail. Said device is a tube store where a plurality of empty tubes are temporarily stored. Once a take-up device  9  has produced a full package on the spindle support and the full package has been deposited at the bobbin store, an empty tube is fed to the spindle support and fastened thereon. 
     The arrangement of the frame parts in the false twist texturing machine according to the invention is such that the yarn from the supply bobbin to the take-up device describes a path in the shape of a  6 . The yarns are conveyed from the creel frame in a straight level course over the winding frame  1  to the processing frame  3 . In the present case, the first delivery mechanism  13  is incorporated into the yarn course in such a way that the yarn is conveyed without significant deflection from the guide roller  11  at the creel frame  2  to the false twisting unit  20  at the processing frame  3 . Said very protective guidance of the yarn enables the use of texturing speeds in excess of 1200 m/min. 
     The guide roller  11  disposed between the first delivery mechanism  13  and the top yarn guides  12  may alternatively be replaced by a yarn guide. 
     A particular advantage of the false twist texturing machine is that the processing frame  3  is disposed at an outside of the machine. It is thereby advantageously possible—in the manner shown in FIG.  10 —to form a double machine. In such a machine, the processing frames of the machine halves are disposed immediately adjacent to one another so that the electric drive components for the false twisting unit and the delivery mechanisms are integrated centrally in a switchgear cabinet disposed at the processing frame. The second machine half is therefore attached in a mirror-inverted manner to the first machine half. 
     As the false twist texturing machine according to FIG. 11 is very similar in construction to the false twist texturing machine according to FIG. 9, reference is made at this point to the description relating to FIG.  9 . 
     In the false twist texturing machine according to FIG. 11, the delivery mechanisms  13 ,  21  and  23  each take the form of a transport roller  30 . 1 ;  30 . 2 ;  30 . 3  having, on its periphery, a zigzag yarn running groove of the type previously described in the description relating to FIGS. 4 to  6 . The transport rollers  30 . 1 ,  30 . 2  and  30 . 3  are associated with a processing point. The transport rollers are driven in each case by means of an individual electric drive  46 . 1 ;  46 . 2 ;  46 . 3 . 
     The transport roller  30 . 1  and the drive  46 . 1  are connected by a holding device  15  to a piecing arm  16 . Here, a yarn cutter  14  disposed in the yarn course upstream of the transport roller  30 . 1  is likewise fastened to the piecing arm. The piecing arm  16  is connected to a slide  32 . The slide  32  is moved by a linear drive along the guide  33  between an operating position  34 —as shown in FIG.  11 —and an attending position  35 . Thus, the yarn at the start of processing may be pieced onto the transport roller  30 . 1  manually by an attendant. The transport roller  30 . 1  is then moved into its operating position  34  by means of the piecing apparatus  17 . 
     Here, there is however the possibility of the drive  46 . 1  being fastened in a stationary manner to the machine frame. The transport rollers  30 . 1  could then, in their respective operating position, be coupled to the drive. 
     For further increased flexibility in the processing point, both the take-up device  9  and the false twisting unit  20  may be driven independently of the adjacent processing points. To said end, the take-up device  9  has two drives. The first drive is used to drive the friction roller  24 . Said drive is advantageously formed by an axle-hung motor which is integrated in the axle of the friction roller. The second drive is used to drive the reciprocating device  26 . Said drive could be a stepping motor which moves a yarn guide back and forth by means of a belt drive. By virtue of said arrangement, the individual adjustability of the delivery mechanisms may be used to produce different yarns inside one texturing machine. 
     In FIG. 12, the cross section of a further embodiment of the false twist texturing machine according to the invention is diagrammatically illustrated. Here, the individual components of the machine are identical to the machine illustrated in FIG.  11 . To said extent, reference is made to the description relating to the embodiment according to FIG.  11 . The arrangement of the components in the embodiment according to FIG. 12 results in a kinked yarn course between the heater  18  and the cooling rail  19 . The yarn transport through the machine is effected by the delivery mechanisms  13 ,  21  and  23 . Here, the yarn  4  is withdrawn from the supply bobbin  7  by the first delivery mechanism  13 . A yarn tensioning device  50  is disposed between the supply bobbin  7  and the first delivery mechanism  13  in order to build up a minimum yarn tensile force. 
     The delivery mechanisms  13 ,  21  and  23  are again formed in each case by a transport roller having a zigzag yarn running track on the periphery of the roller. Guide rollers  11  are disposed upstream and/or downstream of the transport rollers  30 . 1 ;  30 . 2 ;  30 . 3  in order to fix the degree of wrap around the transport roller. Each of the transport rollers is driven by means of an electric motor  46 . 1 ;  46 . 2 ;  46 . 3 . The electric motors of a processing point are connected to a control device  49 . By means of the control device  49  the motors are supplied with the respective setpoint delivery speeds of the rollers. The draw ratio adjusted between the transport roller  30 . 1  and  30 . 2  is therefore held substantially constant. 
     Besides the yarn speed there is however also the possibility of controlling the transport rollers in dependence upon the yarn tensile force. For said purpose, a yarn tensile force sensor might be disposed in or downstream of the false twisting zone and supply its signals to the control device  49 . 
     A preparation device is disposed upstream of the third delivery mechanism  23 . The preparation device here comprises a preparation roller  51 . The preparation roller  51  is driven by means of the roller motor  52 . The preparation roller  51  is disposed in such a way that the yarn  4  touches its surface. Fastened below the preparation roller  51  is a trough  53  filled with the preparing agent. When the preparation roller  51  is rotated, preparing agent is therefore entrained from the trough  53  on the surface of the roller and brought into contact with the yarn  4 . Said arrangement has the advantage that the yarns of the processing point may be individually prepared without influencing the yarns in the adjacent processing point. 
     FIG. 13 shows a further embodiment of a false twist texturing machine. The arrangement of the frame parts and components corresponds substantially to the constructional variant according to FIG.  11 . Reference is therefore made to the description relating to FIG.  11 . 
     In the embodiment of the false twist texturing machine according to FIG. 13, the second heater  22  and the first heater  18  are combined into a heater module. To said end, the yarn  4  after passing through the false twisting unit is deflected through 360° at the delivery mechanism  21 . The yarn  4  in the present case is withdrawn by an additional delivery mechanism  48  from the second delivery mechanism  21  and delivered to the second heater  22 . The yarn tensile force required for the heat aftertreatment is adjusted between the delivery mechanism  48  and the third delivery mechanism  23 . The yarn  4  then runs from above into the take-up device  9 . 
     The delivery mechanisms  13 ,  21 ,  48  and  23  are formed by the transport rollers  30 . 1  to  30 . 4 . Each of the transport rollers  30 . 1  to  30 . 4  is connected to a drive  46 . 1  to  46 . 4 . Control of such drives is again effected via a central control device (not shown here). 
     FIG. 14 shows a further embodiment of a control concept of a false twist texturing machine according to FIG.  11 . In said arrangement the first delivery mechanisms  13 . 1 ,  13 . 2  and  13 . 3  per processing point, which are adjacent in a longitudinal direction of the machine, are shown. The delivery mechanisms  13 . 1 ,  13 . 2  and  13 . 3  are driven in each case by means of a drive  46 . 1 ;  46 . 2 ;  46 . 3 . Associated with each drive is a control device  49 . 1 ;  49 . 2 ;  49 . 3 . The possibility therefore exists of controlling each of the delivery mechanisms individually. The control devices  49 . 1 ,  49 . 2  and  49 . 3  are connected to a central machine control unit  54 . The machine control unit  54  may therefore intervene directly in the individual control of the delivery mechanisms  13 . 1 ,  13 . 2  and  13 . 3 . Thus, a collective adjustment of the delivery mechanisms is possible. Such an arrangement is also particularly suitable for effecting a controlled braking of the delivery mechanisms in the event of a power failure. To said end, an energy store coupled to the machine control unit  54  and associated with each delivery mechanism is activated so that a controlled braking is possible. The energy store is connected to the control device associated with the delivery mechanism. 
     In order after piecing to switch the delivery mechanisms over from a piecing speed to the required operating speed, timing functions are preselected for the control devices and used to control each of the delivery mechanisms. In particular, the speed ratio between the first delivery mechanism and the second delivery mechanism, which determines the stretching of the yarn in the false twisting zone, is not adjusted until shortly before attainment of the final operating speed inside the processing point. The timing function in the present case may effect a ramp-like, progressive or alternatively degressive variation of the rotational speed. 
     In the embodiment of a control concept of the false twist texturing machine illustrated in FIG. 14, the individual control devices  49 . 1 ,  49 . 2  and  49 . 3  may also be combined into a single control device. Such an arrangement is used particularly in cases where only a collective adjustment of the delivery mechanisms is required. 
     In order, particularly in the false twist texturing machine according to FIG. 11, to enable gentle yarn piecing at the first delivery mechanism, a yarn transfer device  55  is associated with the delivery mechanism, e.g. in the manner shown in FIG.  15 . The yarn transfer device  55  here may comprise a swivel arm  56  pivotally supported on a swivelling axle  58 . The swivelling axle  58  is fastened in the machine frame of the texturing machine. A yarn guide  57  is attached to the opposite free end of the swivel arm  56 . The yarn guide  57  may, as a result of the swivelling motion of the swivel arm  56 , penetrate the yarn running plane. Depending on the position of the swivel arm  56 , the yarn  4  at the yarn guide  57  is then transferred in such a way as to set an angle of wrap at the roller  30  which is adjusted in dependence upon the position of the swivel arm. Since the angle of wrap at the roller  30  influences the level of the pressure forces to be transmitted, it is therefore possible with the yarn deflection device also to influence the yarn tension in the yarn  4 . The swivel arm  56  could in said case be connected to a drive, which is wired up with a control device and a yarn tension meter in a control loop. By virtue of such a closed-loop control, each yarn tension required for the process may be adjusted directly by the size of the angle of wrap at the roller  30 . 
     FIG. 16 shows a further embodiment of a drive of a transport roller  30 . For said purpose, the transport roller  30  is fastened on a shaft  60 . The shaft  60  is supported at one free end in a bearing  62  on the machine frame. At the opposite free end, the shaft  60  is coupled to a drive drive  59 . The drive drive  59  here might be formed by a pneumatically operated turbine. Acting on the shaft  60  in its section between the transport roller  30  and the drive unit  59  is an eddy-current brake  61 . Thus, in a simple manner the peripheral speed of the transport roller may be controlled. The drive unit  59  drives the shaft  60  with a constant driving torque. The peripheral speed of the transport roller is then controlled by braking the drive shaft  60  to a greater or lesser extent. 
     FIG. 17 shows a further embodiment of a false twist texturing machine according to the invention. Here, one machine half of a semi-automatic false twist texturing machine is illustrated. Since both machine halves are attached in a mirror-inverted manner to one another, only one half of the double machine is illustrated in FIG.  17  and described. 
     The machine—as already previously described with reference to FIG.  9 —comprises a creel frame  2 , a winding frame  1  and a processing frame  3 . A plurality of supply bobbins  7  are arranged in tiers one above the other in the creel frame  2 . An attending/doffing aisle  5  is formed between the creel frame  2  and the winding frame  1 . Disposed in a flush manner above the machine frames are the first delivery mechanism  13 , the heating device  18  and the cooling device  19 . A false twisting unit  20  and a second delivery mechanism  21  are supported on the processing frame  3 . The processing frame  3  is disposed at the opposite side of the winding frame to the creel frame. Winding frame  1  and processing frame  3  directly abut one another. In the processing frame a second heater  22  is disposed below the second delivery mechanism  21 . The winding frame  1  is used to receive the take-up device  9 . Here too, a plurality of take-up devices are arranged in tiers one above the other. In each of the take-up devices the yarn is wound into a yarn bobbin  25 . The yarn bobbin  25  is disposed on a spindle which is driven via a friction roller  24 . A reciprocating device  26  is inserted in the yarn course upstream of the yarn bobbin. 
     In said arrangement, the first delivery mechanism  13  is formed by a transport roller  30 . The transport roller  30  is fastened by a drive (not shown here) to a height-adjustable slide  32 . The slide  32  may be moved along the guide  33  between an attending position  35  and the operating position  34 . 
     In said arrangement, the yarn  4  is conveyed along the straight yarn course from the top yarn guides  12  of the creel frame  2  to the transport roller  30  and passes from there into the false twisting zone of the machine. The false twisting zone is delimited by the false twisting unit  20  and the transport roller  30 . The heating device  18  and the cooling device  19  are arranged flush inside the false twisting zone. At the outlet of the cooling device  19 , the false-twisted yarn passes via a guide roller  11  to the false twisting unit  20 . The second delivery mechanism  21  conveys the yarn from the false twisting zone into the downstream second heater  22 . From there, the yarn passes via a third delivery mechanism  23  to the take-up device  9 . In the take-up device  9 , the yarn is then wound into a yarn bobbin  25 . Once the bobbins  25  have been completely wound, a doffing apparatus is used to effect the bobbin change at the false twist texturing machine. To said end, a plurality of handling devices which are preferably pneumatically operated are disposed on the doffing apparatus. For the bobbin change, the doffing apparatus travels into the attending/doffing aisle  5  so that the bobbin change is effected simultaneously in each take-up device  9  by means of the handling devices. For said purpose, the yarns are first collected into a bundle, cut and removed by suction. The full packages are released and removed. An empty tube is then inserted in each take-up device. The yarns are inserted for winding. Each activity is effected by the handling devices of the doffing apparatus. The new winding process in the take-up device may begin. 
     In said semi-automatic false twist texturing machine also, it is possible to realize a particularly gentle yarn processing. By virtue of the arrangement of the first delivery mechanism immediately upstream of the heater inlet of the heating device  18  and above the creel frame  2 , a yarn course having few deflections is realized.