JP2023024347A - Draft system, and method for loading and opening draft system - Google Patents

Abstract

To provide a draft system for drafting a fiber bundle for an air-jet spinning machine.SOLUTION: A draft system comprises a frame 2, and a plurality of bottom rollers 5, 6 and 8. Each bottom roller is installed at a bearing point 4. The bottom rollers are engaged with top rollers 11, 12 and 13 to form an inlet roller pair, an intermediate roller pair and a discharge roller pair. A load carrier 20 having a pressure element 22 for loading the top rollers, and a holding element 23 for holding and lifting the top rollers is arranged on a pivot bearing 21, a receptacle 19 for a spinning nozzle 18 is arranged in the frame, and the spinning nozzle is arranged just beyond the discharge roller pair. A discharge top roller that is installed on a bearing connected to the bearing point 4 of a discharge bottom roller, is loaded by the load carrier, and is unmounted, therefore remains in the bearing when the load carrier is activated and opened.SELECTED DRAWING: Figure 2

Description

The present invention relates to a drafting system for drafting fiber bundles for an air-jet spinning machine, the drafting system comprising a frame for the drafting system and a plurality of drivable bottom rollers, each bottom roller bearing a point on the frame. each bottom roller engaging a top roller, the bottom and top rollers forming a pair of inlet rollers, at least one pair of intermediate rollers, and a pair of discharge rollers for pivoting the load carrier in pivot bearings on the frame; directly after the discharge roller pair, the load carrier comprising a pressure element for loading the top roller and a retaining element for holding and lifting the top roller when the load carrier is pivoted open; A receptacle for the spinneret is arranged on the frame in order to place the spinneret in the frame. The invention further relates to a drafting system loading and opening method.

US Pat. No. 6,300,000 discloses a twin unit containing two drafting systems for drafting a sliver usable in a spinning machine. A twin unit comprises a common frame for two drivable drafting systems, which are removably mounted within the machine frame. The draft system comprises a plurality of drivable bottom rollers arranged substantially mirror symmetrically to one another. Each bottom roller has an area for stretching the slivers and has two bearing points. The spinning nozzle can be arranged in the frame of the twin unit together with the draft system and the stripping roller pair.

Accurate alignment of the top roller and spinneret to the discharge bottom cylinder is particularly important in order to be able to control the airflow conditions around the fiber entry area of the draft system air jet spinner, especially the spinneret. High transport speeds and consequent high surface velocities at the discharge roller pair create air turbulence which adversely affects fiber flow. To limit air turbulence, the spinning nozzle should be fairly close to the top discharge roller. The spinning nozzle should wrap around the delivery roller pair by means of its contour, thereby preventing as far as possible the formation of air resistance flows in said region.

Known splicing methods, such as that described, for example, in US Pat. This required a very complicated mechanism. Discharge top rollers and discharge bottom cylinders were housed in separate areas of the machine. The resulting series tolerance was not ideal given the accuracy desired for the rollers.

However, alignment and positioning of the discharge top roller with respect to the discharge bottom cylinder and spinning nozzle becomes more of an issue when the discharge top roller is housed in the load carrier and lifted therewith. Due to the long distance between the pivot axis and the discharge bottom cylinder, the motion of the load carrier on the pivot bearings and the long lever on the load carrier to the discharge top roller, the top discharge roller cannot be accurately positioned. This disadvantage cannot be compensated for by design measures or more precise manufacturing of the load carrier pivot bearings.

German Offenlegungsschrift 10 2005 027 193 Japanese Patent Publication No. 59-204925

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a draft system for an air-jet spinning machine, and a loading and unloading draft system for an air-jet spinning machine, which allows the discharge top roller to be accurately positioned with respect to the discharge bottom roller and the spinning nozzle. to provide a method.

This object is achieved by a drafting system and method having the features of the independent claims.

A drafting system according to the invention for drafting slivers for an air-jet spinning machine comprises a frame for the drafting system and a plurality of drivable bottom rollers, each bottom roller being mounted on a bearing point of the frame. To adjust the spacing of the bottom rollers, the bearing points of the bottom rollers can be attached to rails on the frame. Each bottom roller engages a top roller, the bottom and top rollers forming an entry roller pair, at least one intermediate roller pair, and a discharge roller pair. Depending on the type of drafting system, for example, two intermediate roller pairs with especially straps and strap deflections can be provided. Additionally, a load carrier is pivotally disposed in pivot bearings on the frame.

The load carrier comprises a pressure element for loading the top roller and a holding element for holding and lifting the top roller when the load carrier is pivoted open. When the load carrier is closed, the top roller presses against the bottom roller using a pressure element to form a clamping point for stretching the slivers. A retaining element attaches the top roller to the load carrier and allows the top roller to be lifted from the bottom roller when the load carrier is opened or lifted. The draft system is thus opened so that the slivers to be drafted can be introduced manually into the draft system, for example.

The frame is provided with a spinning nozzle receptacle for arranging the spinning nozzle directly behind the delivery roller pair. By arranging the spinning nozzle and the discharge bottom roller on the frame, the distance between the spinning nozzle and the discharge bottom roller is always maintained at the same desired distance. Therefore, the spinning nozzle can be placed fairly close to the discharge bottom roller, since it is not necessary to observe tolerances caused by relative displacements.

According to the invention, the top discharge roller is mounted on a bearing connected to the bearing point of the mating bottom discharge roller. The bearing of the top discharge roller and the bearing point of the bottom discharge roller can be integrally mounted or at least connected to each other fixedly, for example screwed. Therefore, no deviation occurs between the bearing of the discharge top roller and the bearing point of the discharge bottom roller. This permits a very precise positioning of the fixedly mounted discharge top roller relative to the fixedly mounted discharge bottom roller and thus to the likewise fixed spinning nozzle. .

Further, according to the present invention, since the top discharge roller is loaded by the load carrier, but is not attached to the load carrier, precise positioning can also be achieved with great accuracy. Therefore, the load carrier only needs to press the discharge top roller against the discharge bottom roller with a prescribed force. When the draft system opens, i.e. when the load carrier is pivoted open, the discharge top roller is not lifted from the discharge bottom roller with the load carrier and remains in its bearings. Thus, even when the draft system is open, the correct engagement of the top and bottom discharge rollers and the spinning nozzle is maintained. This allows for very good engagement and precision in the position of the top roller with respect to the spinning nozzle. When the draft system is closed again, i.e. when the load carrier is returned to a position where it forces the top roller against the bottom roller, the position of the top discharge roller relative to the bottom discharge roller and the spinning nozzle is retained. In this way series tolerances are avoided and ultimately the spinning results are greatly improved.

It is particularly advantageous if the bearing of the top discharge roller is a slotted guide. The slotted guide is easy to manufacture and ensures that the discharge top roller is particularly well guided in the bearing. Tolerances are kept low, which improves the engagement of the top discharge roller with its bottom discharge roller and the spinning nozzle.

It is also advantageous if the pressure element is a spring, in particular a leaf or spiral spring, or a pneumatic or hydraulic pressure element. In particular, the leaf spring is particularly advantageous for loading the top discharge roller as it has a simple construction in which the leaf spring only needs to push against the top discharge roller or its shaft when the draft system is closed.

It is advantageous if the load carrier has a wide slotted guide, especially for the top discharge roller. A wide slotted guide ensures that the discharge top roller or its axis is contained normally without contact. Said slotted guide only participates in the positioning of the shaft, especially if the shaft is not exactly in the bearing in the slotted guide. This ensures that the draft system will not be damaged.

Furthermore, it is advantageous if the shaft of the top delivery roller is provided with a collar for axial positioning in the bearing. This greatly facilitates axial positioning of the top discharge roller. The collar acts laterally on, for example, bearings or slotted guides to ensure that the top discharge roller is positioned directly above the bottom discharge roller.

Advantageously, the shaft of the top delivery roller is held in bearings by a holding device, in particular a holding spring. A retention device ensures that the top discharge roller is retained in the bearings even when the load carrier is lifted.

When the drafting systems are arranged in a twin unit, two drafting systems are arranged on the frame in the twin unit, the two drafting systems are provided with mutually independent drives, and the drafting systems are substantially mirror-symmetrical to each other. It is also advantageous if Twin units are cheaper to manufacture than multiple single units. The twin unit can be assembled to the spinning machine in a shorter time than the single unit.

It is also advantageous if at least the discharge top rollers of the two draft systems are implemented as twin rollers with a common axis. Discharge top rollers are rotatably disposed at opposite ends on a common axis. The shaft can be held in one or two bearings on the frame. In this case, two adjacent delivery top rollers are similarly arranged with respect to their delivery bottom rollers and the two spinning nozzles.

Furthermore, it is advantageous if the load carrier loads the top rollers of both drafting systems together. Here, the load carrier is mounted such that it can simultaneously lift the top rollers of two adjacent draft systems, other than the discharge top roller, from the bottom rollers. Lowering the load carrier, ie closing the draft system, exerts a compressive force on all roller pairs of the two adjacent draft systems.

It is particularly advantageous if the bearing of the top discharge roller is arranged such that its position can be adjusted with respect to the bearing point of the mating bottom discharge roller. Adjustments can be made using slots and fixing screws. The diameter of the top roller may vary due to the need for cover polishing after a period of use. Therefore, it may be necessary to adjust the bearing of the top roller towards the spinning nozzle or relative to the bearing of the bottom roller.

Advantageously, the bearings of the top discharge roller, which is embodied as twin rollers with a common axis, can be adjusted together. In that case the bearings can be displaced in pairs, for example in the slots. The adjustment range is usually sufficient in the area of radius reduction to the reference grind of a few millimeters.

In the method according to the invention for loading and unloading the draft system of an air-jet spinning machine having bottom and top rollers, each bottom roller engages a top roller. The bottom and top rollers form an entry roller pair, at least one intermediate roller pair, and a discharge roller pair. It is also possible to arrange several intermediate roller pairs in the draft system. The load carrier, on which the top roller of the draft system is located, can pivot to an open or closed position. A load carrier loads the top roller into its closed position. That is, the load carrier forces the top roller against the mating bottom roller of the drafting system. The load carrier also lifts the top roller from the bottom roller in the open, lifted position and holds it in the open position. A spinning nozzle for spinning the fiber bundle drawn by the draft system is placed immediately after the pair of discharge rollers.

According to the invention, the top discharge roller is mounted on the mating bottom discharge roller. Therefore, the engagement of the top discharge roller and its bottom discharge roller is very precisely defined. The two rollers do not shift relative to each other as the drafting system opens and closes, so there is no in-line tolerance that could lead to inaccurate engagement with each other. Further, because the discharge top roller is loaded by the load carrier but is not attached to the load carrier, said discharge top roller remains in bearings when the load carrier is pivoted open thereby providing a discharge top roller. It ensures that the rollers are always exactly positioned with respect to the bottom roller and are in very good condition, allowing even very high spinning speeds in the spinning nozzle.

In a particularly advantageous embodiment of the invention, the delivery top roller pair, like the delivery bottom cylinder bearing, is received by a receiving fork integrated into the draft system frame. The receiving fork is a slotted guide that ensures the position of the discharge top roller relative to the discharge bottom cylinder and allows for changes in diameter of the top cylinder after the cover is ground. While the load carrier is open, the top discharge roller remains in the plane of the drafting system where the slivers to be drafted reside.

The top discharge roller is held in a slotted guide and is prevented from falling off by a holding spring. Retaining springs are mounted so that the top roller axle can be attached to and withdrawn from the slotted guide.

The top roller has a collar or recess on its axis by which said top roller is axially aligned. The top roller is placed in the intended axial position over the slotted guide by means of its collar or recess.

For twin units, two bearing receptacles for the left and right discharge bottom cylinders and two slotted guides are built into the draft system frame. This ensures a very precise alignment of the top roller and bottom cylinder. The spinning nozzles are also housed in the draft frame, which ensures that the spinning nozzles are accurately positioned with respect to the discharge top and bottom rollers.

When the carrier closes, the top discharge roller is preferably loaded by a spring element, particularly a leaf spring, received within the load carrier. Of course, spiral springs can also be used. Pneumatic or hydraulic loading is also possible.

The invention can be implemented according to the above description and the features mentioned can be implemented individually or in any combination.

Further advantages of the invention are illustrated in the following examples. Each outline is shown.

1 is a side view of a closed draft system according to the invention; FIG. FIG. 2 is the draft system system of FIG. 1 in an open position; FIG. 3 is a side view of the frame. 4 is a plan view of the frame of FIG. 3; FIG. FIG. 5 is a plan view of the bearing of the top discharge roller. FIG. 6 is a side view showing a displaceable mounting device for the discharge top roller. FIG. 7 is a plan view showing a common displaceable mounting device for the discharge top roller.

In the following description of alternative embodiments, the same reference symbols are used for features that are the same and/or at least equivalent in their design and/or mode of operation compared to other embodiments. If the detailed description of individual features is not repeated, their design and/or function corresponds to the design and function of the preceding features. For clarity of overview, reference numbers for components already described may not be inserted in the following figures.

The draft system 1 comprises a frame 2 arranged on a machine frame 3 of an air jet spinning machine. Displaceable bearing points 4 for an input bottom roller 5 and two intermediate bottom rollers 6 are arranged on the frame 2 . One of the intermediate bottom rollers 6 is provided with a strap 7 . Arranged behind the strap 7 is a discharge bottom roller 8, the bearing point 4 of which is fixed here in one piece to the frame 2. FIG. Each bottom roller 5 , 6 , 8 is driven by a motor 9 and a drive belt 10 . Each bottom roller 5 , 6 , 8 has an engaging top roller 11 , 12 and 13 and strap 17 engages strap 7 . The input bottom roller 5 forms an input roller pair 14 together with the input top roller 11, the two intermediate bottom rollers 6 together with the two intermediate top rollers 12 each form an intermediate roller pair 15, and the discharge bottom roller 8 forms a discharge top. A discharge roller pair 16 is formed together with the roller 13 . A spinning nozzle 18 is arranged on the frame 2 in a receptacle 19 following the delivery roller pair 16 . The receptacle 19 allows the spinning nozzle 18 to be tilted as needed to perform maintenance on the spinning nozzle 18 . The spinneret 18 is adapted to the peripheral shape of the discharge bottom roller 8 and the discharge top roller 13 so as to create an unobstructed flow of the fibers conveyed through the draft system 1 and the spinneret 18 .

Top rollers 11 and 12 are arranged on load carrier 20 . The load carrier 20 can pivot via pivot bearings 21 whereby said load carrier is shown here with top rollers 11, 12 and 13 resting on bottom rollers 5, 6 and 8. From the closed position shown in FIG. 2, movement to the open position of FIG. In the closed position of drafting system 1 shown in FIG. A clamping line forms between them, where the fibers of the slivers traveling through the drafting system 1 are clamped and drawn together by the different speeds of the roller pairs 14, 15 and 16. The pressure element can act mechanically, for example in the form of a spring, or said pressure element can be a pneumatic or hydraulic pressure element.

Top rollers 11 and 12 are attached to load carrier 20 by retaining elements 23 . The retaining element 23 lifts the top rollers 11 and 12 together with the strap 17 from the bottom rollers 5 , 6 and the engaging strap 7 when the load carrier 20 is opened, i.e. pivoted about the pivot bearing 21 . In contrast, top discharge roller 13 is not mounted on load carrier 20 with holding element 23 . Only the pressure element 22 is attached to the load carrier 20 and presses the top discharge roller 13 against the bottom discharge roller 8 in the closed state. A wide slotted guide 24 is mounted on the load carrier 20 to roughly guide the discharge top roller 13 and the load carrier 20 during opening and closing, said wide slotted guide being a discharge top roller 13, not shown here. It loosely encompasses the axis of roller 13 . Therefore, when the load carrier 20 opens, the top discharge roller 13 is not lifted off its bottom discharge roller 8 and remains above it.

Relatedly, FIG. 2 shows the draft system 1 of FIG. 1 in an open state. The load carrier 20 and pivot bearings 21 are pivoted to lift the top rollers 11,12 and straps 17 from their bottom rollers 5,6 and bottom straps 7. In this state, the slivers (not shown here) present in the draft system 1 can be removed or inserted as required. The delivery top roller 13 remains on its delivery bottom roller 8 and is therefore in very precise engagement with the spinning nozzle 18 . The discharge top roller 13 does not have to be removed each time the draft system 1 is opened or the load carrier 20 is lifted and therefore due to the fixed engagement between the discharge bottom roller 8 and the spinning nozzle 18 it is very Accurate, low-tolerance installation is possible.

From FIG. 2 it can be seen that the pressure element 22 and the holding element 2 remain connected to the top rollers 11 and 12 . However, the pressure element 22 that applies the compressive force to the top discharge roller 13 is released from the top discharge roller 13 and lifted together with the load carrier 20 . Said pressure element 22 is surrounded by a wide slotted guide 24 which serves to secure the top discharge roller 13 more securely and to ensure that the load carrier closes. roughly guides the load carrier 20 about the axis of .

FIG. 3 shows a side view of the frame 2 of previous FIGS. 1 and 2. FIG. A bearing point 4 for a discharge bottom roller 8 is fixedly connected to the frame 2 . The bearing point 4 comprises an opening 25 in which the roller bearing (not shown) of the discharge bottom roller 8 can be arranged. Furthermore, the stationary parts of the receptacles 19 and pivot bearings 21 are arranged on the frame 2 .

A bearing 26 for the shaft 27 of the top discharge roller 13 is provided as a structural unit with the bearing point 4 of the bottom discharge roller 8 . Bearing 26 comprises a slotted guide 28 that guides and precisely positions shaft 27 . Since the slotted guide 28 is fixedly engaged with the frame 2 and also with the receptacle 19 by means of the bearing 26 and the bearing point 4 , the observed tolerances are small and the difference between the delivery roller pair 16 and the spinning nozzle 18 is The entire delivery roller pair 16 can be arranged with respect to the spinning nozzle 18 in such a way that the distance between . This results in little or no air turbulence as the slivers are conveyed through the draft system 1 and spinneret 18 .

FIG. 4 shows a plan view of the frame 2 of previous FIGS. The frame 2 is a twin unit component on which two drafting systems 1 are arranged. The bottom rollers 5, 6 and 8 of the two drafting systems 1 are provided with individual drives independent of each other so that they can be operated independently of each other. The drive belt 10 (see FIG. 1) is arranged in an internal space 29 of the frame 2, for example. The frame 2 also comprises guide rails 30 in which the bearing points 4 of the input bottom roller 5 and the intermediate bottom roller 6 are longitudinally displaceable. Thus, the distances between the bottom rollers 5, 6, 8 can be adjusted relative to each other. The stationary portion of the pivot bearing 21 is arranged between the guide rails 30 on which the pivot bearing of the load carrier 20 is pivotally mounted. A load carrier 20 is responsible for loading the top rollers 11 , 12 , 13 of both drafting systems 1 . The frame 2 further comprises two bearing points 4 for the two discharge bottom rollers 13 which are fixedly connected to the frame 2 . Similarly, two receptacles 19 for two spinning nozzles 18 are provided which engage the two drafting systems 1 of the frame 2 .

Bearings 26 and slotted guides 28 are fixedly arranged at respective bearing points 4 of frame 2 . The frame 2 thereby preferably provides an integral base for the bearing point 4 of the discharge bottom roller 8, the receptacle 19, the pivot bearing 21 and the bearing 26 for the discharge top roller 13, which are not mutually displaceable. Form. Said bearings can therefore be manufactured very precisely, so that the delivery roller pair 16 and the spinning nozzle 18 are in very close and precisely fitted engagement.

FIG. 5 shows a plan view of the bearing of the discharge top roller 13. As shown in FIG. A frame 2 , which is only partially shown here, forms the base of a twin unit with two parallel draft systems 1 . Two bearing points 4 for the discharge bottom roller 8 are arranged fixedly on the frame 2 . A bearing 26 for the discharge top roller 13 with a slotted guide 28 is present on the bearing point 4 . A slotted guide 28 guides an axle 27 which, like twin rollers 31, is provided with the discharge top rollers 13 of each draft system 1 at its ends. A collar 32 is provided on the shaft 27 in the region of each bearing 26 . Collar 32 supports shaft 27 on bearings 26 and axially positions twin rollers 31 . As a result, each discharge top roller 13 is positioned above the discharge bottom roller 8 .

Furthermore, a retaining spring 33 is provided in the area of the bearing point 4 . A retaining spring 33 ensures that the twin rollers 31 or the top discharge roller 13 are not unintentionally disengaged from their bearings 26 . To remove the twin rollers 31 from the bearings 26 it is necessary to loosen or bend the retaining springs 33 so that the shaft 27 can be removed from the bearings 26 and its slotted guides 28 .

Further, FIG. 5 shows how the shaft 27 is pressed against its discharge bottom roller 8 by the pressure element 22 of the load carrier 20 . A wide slotted guide 24 is provided for coarse positioning of the load carrier 20 with respect to the axis 27 of the frame 2 and twin rollers 31 . Said slotted guide 24 loosely engages around axis 27 so that pressure element 22 is particularly correctly positioned on axis 27 when load carrier 20 is closed.

As can be seen in particular from this FIG. 5, the shaft 27, and thus each top discharge roller 13, is very accurately positioned axially and radially, the gap between the top discharge roller 13 and the spinning nozzle 18 being: It can always be kept very small. This ensures particularly good spinning results using the invention.

FIG. 6 is a side view showing a displaceable mounting device for the discharge top roller 13. As shown in FIG. A bearing 26 with a slot 28 is mounted separately from the bearing point 4 of the discharge bottom roller 8 . The separation point is implemented as a bearing surface 34 along which the bearing 26 can be adjusted relative to the bearing point 4 and thus relative to the spinning nozzle 18 . A double arrow V indicates the adjustment range. After properly adjusting the position, the bearing 26 is fixedly connected to the bearing point 4 using screws 35 .

Adjustment of the bearings 26 may be necessary when using top discharge rollers 13 with different diameters, for example when the cover of the top discharge roller 13 needs to be ground. Of course, the bearing 26 can also be mounted directly on the frame 2, fixedly or movably. As shown here, the bearing surface 34 can be mounted at an angle so that horizontal and vertical adjustments can be made simultaneously. However, depending on the bearing surface of the bearing 26 and its mounting, a simple horizontal and/or vertical adjustment is also possible. What is important here is to be able to optimally adjust the position of the top discharge roller 13 with respect to the spinning nozzle 18 .

FIG. 7 shows a top view of a common displaceable bearing for twin rollers 31 with a common axis 27 (FIG. 5). The two bearings 26 are connected to each other by connecting webs 37 in order to adjust the shaft 27 and to be able to adjust the two top delivery rollers 13 of the twin unit simultaneously. The whole unit can thus be moved in the slot 36 according to the double arrow V and fixed using a screw 35 in each case.

The invention is not limited to the illustrated and described embodiments. Variations within the scope of the claims are possible and any combination of the described features will also define the scope of the independent claims, even if the aforementioned features appear in different parts of the specification or claims or in different embodiments. It is possible as long as it does not contradict the teaching.

1 Draft system 2 Frame 3 Machine frame 4 Bearing point 5 Input bottom roller 6 Intermediate bottom roller 7 Strap 8 Discharge bottom roller 9 Engine 10 Drive belt 11 Input top roller 12 Intermediate top roller 13 Discharge top roller 14 Entrance roller pair 15 Intermediate roller pair 16 discharge roller pair 17 strap 18 spinning nozzle 19 receptacle 20 load carrier 21 pivot bearing 22 pressure element 23 holding element 24 wide slotted guide 25 opening 26 bearing 27 shaft 28 slotted guide 29 interior space 30 guide rail 31 twin roller 32 collar 33 retaining spring 34 bearing surface 35 screw 36 slot 37 connecting web

Claims (12)

A drafting system for drafting fiber bundles for an air jet spinning machine, comprising:
a frame (2) for said draft system (1);
comprising a plurality of drivable bottom rollers (5, 6, 8);
each bottom roller (5, 6, 8) is mounted at a bearing point (4) on said frame (2),
Each bottom roller (5, 6, 8) engages a top roller (11, 12, 13), said bottom and top rollers (5, 6, 8, 11, 12, 13) forming an inlet roller pair (14). , forming at least one intermediate roller pair (15) and a discharge roller pair (16),
a load carrier (20) is pivotally arranged in a pivot bearing (21) on said frame (2);
Said load carrier (20) comprises a pressure element (22) for loading said top rollers (11, 12, 13) and a top roller (11, 12) when said load carrier (20) is pivoted open. ) with a holding element (23) for holding and lifting the
A draft system wherein a receptacle (19) for said spinning nozzle (18) is arranged on said frame (2) for arranging said spinning nozzle (18) directly behind said pair of delivery rollers (18) ,
Said top discharge roller (13) is mounted on a bearing (26) connected to said bearing point (4) of said mating bottom discharge roller (8), said top discharge roller (13) being mounted on said load carrier. (20) but not attached to the load carrier (20), the discharge top roller remains in the bearing (26) when the load carrier (20) is pivoted open. A draft system characterized by: Draft system according to claim 1, characterized in that the bearing (26) of the top discharge roller (13) is a slotted guide (28). Draft system according to claim 1 or 2, characterized in that the pressure element (22) is a spring, in particular a leaf or spiral spring, or a pneumatic or hydraulic pressure element. Draft according to any one of the preceding claims, characterized in that the load carrier (20) comprises a particularly widened slotted guide (24) for the discharge top roller (13). system. 5. Any one of claims 1 to 4, characterized in that said shaft (27) of said top discharge roller (13) comprises at least one collar (32) for axial positioning in said bearing (26). or the draft system according to item 1. 6. Any one of claims 1 to 5, characterized in that the shaft (27) of the top delivery roller (13) is held in the bearing (26) by a holding device, in particular a holding spring (33). The draft system described in . said drafting system (1) is arranged in a twin unit in which two drafting systems (1) are arranged on said frame (2), said two drafting systems (1) having drives independent of each other, Draft system according to any one of the preceding claims, characterized in that the draft systems (1) are arranged substantially mirror-symmetrical to each other. 8. Any one of claims 1 to 7, characterized in that at least the discharge top rollers (13) of the two draft systems (1) are implemented as twin rollers (31) with a common axis (27). Draft system as described in section. Draft according to any one of the preceding claims, characterized in that the load carrier (20) loads together the top rollers (11, 12, 13) of both draft systems (1). system. Claim characterized in that said bearing (26) of said top delivery roller (13) is arranged adjustably with respect to said bearing point (4) of said delivery bottom roller (8) with which it engages. 10. The draft system according to any one of Items 1 to 9. 11. Any one of claims 1 to 10, characterized in that the bearings (26) of the discharge top roller (13) implemented as twin rollers (31) with a common axis (27) are jointly adjustable. or the draft system according to item 1. A method of loading and opening a draft system of an air jet spinning machine with bottom and top rollers (5, 6, 8, 11, 12, 13),
Each bottom roller (5, 6, 8) engages a top roller (11, 12, 13), said bottom and top rollers (5, 6, 8, 11, 12, 13) forming an inlet roller pair (14). , forming at least one intermediate roller pair (15) and a discharge roller pair (16),
the load carrier (20) can pivot to an open or closed position;
the load carrier (20) loads the top rollers (11, 12, 13) in the closed position and holds and lifts the top rollers (11, 12) in the open position;
A method in which a spinning nozzle (18) for spinning the fiber bundle drawn by the draft system (1) is arranged immediately after the discharge roller pair (16),
Said discharge top roller (13) is mounted on said discharge bottom roller (8) in engagement,
Said discharge top roller (13) is loaded by said load carrier (20) but is not attached to said load carrier (20) so that when said load carrier (20) is pivoted open, said A method, characterized in that the discharge top roller remains within said bearing (26).

Images