Draft system and methods for loading and opening the draft system

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

Technical Field

[0001] The present invention relates to a drafting system for drafting a fiber bundle for an air jet spinning machine. The drafting system includes a frame for the drafting system and a plurality of drivable bottom rollers. Each bottom roller is installed at a bearing point on the frame. Each bottom roller engages with a top roller, and the bottom and top rollers form an inlet roller pair, at least one intermediate roller pair, and a delivery roller pair. A load carrier is pivotally arranged on a pivot bearing on the frame. The load carrier includes a pressure element for loading the top roller and a holding element for holding and lifting the top roller when the load carrier pivots open. A receptacle for the spinning nozzle is arranged on the frame for arranging the spinning nozzle immediately behind the delivery roller pair. The present invention further relates to a method for loading and opening the drafting system.

Background Art

[0002] Patent Document 1 discloses a twin unit including two drafting systems for drafting a fiber bundle usable in a spinning machine. The twin unit includes a common frame for two drivable drafting systems, and the frame is removably attached within a machine frame. The drafting system includes a plurality of drivable bottom rollers, which are arranged substantially mirror-symmetrically to each other. Each bottom roller has a region for stretching the fiber bundle and has two bearing points. The spinning nozzle can be arranged on the frame of the twin unit together with the drafting system and the stripping roller pair.

[0003] In air-jet spinning machines with draft systems, precise alignment of the top roller and spinning nozzle relative to the discharge bottom cylinder is particularly important to control the airflow conditions, especially around the fiber inlet area of ​​the spinning nozzle. High conveying speeds, resulting in high surface velocities at the discharge roller pair, generate turbulence, negatively impacting fiber flow. To limit air turbulence, the spinning nozzle needs to be positioned quite close to the discharge top roller. The spinning nozzle's shape should be used to enclose the discharge roller pair, thereby preventing the formation of air resistance flow in that area as much as possible.

[0004] For example, in known yarn splicing methods such as those described in Patent Document 2, the top discharge roller of the spinning station had to be lifted separately from the top rollers of the other draft system. This required a very complex mechanism. The top discharge roller and the bottom discharge cylinder were housed in separate areas of the machine. The resulting series tolerances were not ideal in terms of the precision desired for the rollers.

[0005] However, when the discharge top roller is housed in the load carrier and lifted together with it, aligning and positioning the discharge top roller relative to the discharge bottom cylinder and spinning nozzle becomes a greater problem. The long distance between the pivot axis and the discharge bottom cylinder, the movement of the load carrier at the pivot bearing, and the long lever of the load carrier to the discharge top roller make it impossible to precisely position the discharge top roller. This disadvantage cannot be compensated for by designing or manufacturing the pivot bearing of the load carrier more precisely. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] German Published Patent No. 10 2005 027 193 [Patent Document 2] Japanese Published Patent No. 59-204925 [Overview of the project] [Problems that the invention aims to solve]

[0007] Therefore, an object of the present invention is to provide a draft system for an air-jet spinning machine that can accurately position the discharge top roller relative to the discharge bottom roller and the spinning nozzle, and a method for loading and unloading the draft system for an air-jet spinning machine. [Means for solving the problem]

[0008] This objective is achieved by a drafting system and method having the features of the independent claims. [Effects of the Invention]

[0009] A draft system according to the present invention for drafting fiber bundles for an air-jet spinning machine comprises a frame for the draft system and a plurality of drivable bottom rollers, each bottom roller mounted at a bearing point on the frame. To adjust the spacing of the bottom rollers, the bearing points of the bottom rollers can be mounted on rails on the frame. Each bottom roller engages with a top roller, and the bottom and top rollers form an inlet roller pair, at least one intermediate roller pair, and an outlet roller pair. Depending on the type of draft system, for example, two intermediate roller pairs may be provided, particularly with straps and strap deflections. Furthermore, a load carrier is pivotably positioned on a pivot bearing on the frame.

[0010] The load carrier comprises a pressure element for loading the top roller and a retaining element for holding and lifting the top roller when the load carrier pivots and opens. When the load carrier closes, the pressure element is used to press the top roller against the bottom roller, forming a clamping point for stretching the fiber bundle. The retaining element attaches the top roller to the load carrier, so that when the load carrier is opened, i.e., lifted, the top roller is lifted away from the bottom roller. The draft system is thus opened, and the fiber bundle to be drafted can be introduced into the draft system, for example, manually.

[0011] The frame is provided with a receptacle for the spinning nozzle, which positions the spinning nozzle immediately after the discharge roller pair. By positioning the spinning nozzle and 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 positioned quite close to the discharge bottom roller, as it is not necessary to observe tolerances resulting from relative displacement.

[0012] According to the present invention, the discharge top roller is mounted on a bearing connected to the bearing point of the engaging discharge bottom roller. The bearing of the discharge top roller and the bearing point of the discharge bottom roller can be mounted integrally or at least fixedly connected to each other, for example by screw fastening. Therefore, no misalignment occurs between the bearing of the discharge top roller and the bearing point of the discharge bottom roller. This allows the fixedly mounted discharge top roller to be positioned very accurately relative to the fixedly mounted discharge bottom roller, and by extension, to the similarly fixed spinning nozzle.

[0013] Furthermore, according to the present invention, although the discharge top roller is loaded by the load carrier, it is not attached to the load carrier, so precise positioning can be achieved with considerable accuracy. Therefore, the load carrier only needs to press the discharge top roller against the discharge bottom roller with a specified force. When the draft system opens, i.e., when the load carrier pivots open, the discharge top roller is not lifted away from the discharge bottom roller with the load carrier, but remains within its bearing. Therefore, even when the draft system is open, the precise engagement between the discharge top roller, the discharge bottom roller, and the spinning nozzle is maintained. This allows for extremely good engagement and precision in the position of the top roller relative to the spinning nozzle. When the draft system is closed again, i.e., when the load carrier is returned to the position where it presses the top roller against the bottom roller, the position of the discharge top roller relative to the discharge bottom roller and the spinning nozzle is maintained. In this way, series tolerances are avoided, and the spinning results are ultimately greatly improved.

[0014] It is particularly advantageous if the bearing of the discharge top roller is a slotted guide. Slotted guides are easy to manufacture and ensure that the discharge top roller is guided particularly well within the bearing. Tolerances can be kept low, thereby stably improving the engagement of the discharge top roller with the discharge bottom roller and the spinning nozzle.

[0015] It is also advantageous if the pressure element is a spring, particularly a leaf spring or spiral spring, or a pneumatic or hydraulic pressure element. In particular, a leaf spring is especially advantageous for loading the discharge top roller because it has a simple structure in which the leaf spring only needs to press against the discharge top roller or its axis when the draft system is closed.

[0016] A load carrier is advantageous, especially if it has wide slotted guides for the discharge top roller. The wide slotted guides ensure that the discharge top roller or its shaft is securely enclosed, usually without contact. The slotted guides are only involved in shaft positioning if the shaft is not precisely in the bearing within the slotted guide. This ensures that the draft system is not damaged.

[0017] Furthermore, it is advantageous to have a collar for axial positioning of the discharge top roller's axis within the bearing. This makes axial positioning of the discharge top roller very easy. The collar acts laterally on, for example, the bearing or slotted guide, ensuring that the discharge top roller is positioned directly above the discharge bottom roller.

[0018] It is advantageous if the shaft of the discharge top roller is held within the bearing by a retaining device, particularly a retaining spring. The retaining device ensures that the discharge top roller is securely held within the bearing even when the load carrier is lifted.

[0019] When a draft system is arranged in a twin unit, it is also advantageous if the twin unit has two draft systems mounted on a frame, each with its own independent drive mechanism, and the draft systems are arranged substantially mirror-symmetrically to each other. Twin units can be manufactured at a lower cost than multiple single units. Assembly into the spinning machine is also quicker with twin units than with single units.

[0020] It is also advantageous when at least the discharge top rollers of the two draft systems are implemented as twin rollers having a common axis. The discharge top rollers are rotatably positioned at both ends on the common axis. The axis can be held by one or two bearings on the frame. In this case, the two adjacent discharge top rollers are similarly positioned with respect to their discharge bottom rollers and two spinning nozzles.

[0021] Furthermore, it is advantageous for the load carrier to load the top rollers of both draft systems together. Here, the load carrier is implemented such that it can simultaneously lift the top rollers of two adjacent draft systems other than the delivery top roller from the bottom rollers. When the load carrier is lowered, i.e., the draft system is closed, a compressive force is applied to all roller pairs of the two adjacent draft systems.

[0022] It is particularly advantageous when the bearing of the delivery top roller is arranged such that its position can be adjusted relative to the bearing point of the engaging delivery bottom roller. The adjustment can be carried out using a slot and a fixing screw. Since the cover needs to be polished after a certain period of use, the diameter of the top roller can vary. 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.

[0023] Advantageously, the bearings of the delivery top roller implemented as twin rollers having a common axis can be adjusted together. In that case, the bearings are displaceable in pairs, for example, within a slot. The adjustment range is usually sufficient in the region of radius reduction with respect to a few millimeters of reference grinding.

[0024] In the method according to the invention for loading and releasing the drafting system of an air-jet spinning machine having bottom and top rollers, each bottom roller engages with a top roller. The bottom and top rollers form an inlet roller pair, at least one intermediate roller pair, and a delivery roller pair. It is also possible to arrange a plurality of intermediate roller pairs in the drafting system. The load carrier on which the top rollers of the drafting system are arranged can pivot to an open position or a closed position. The load carrier loads the top rollers into their closed position. That is, the load carrier presses the top rollers against the bottom rollers that engage with the drafting system. The load carrier also lifts the top rollers from the bottom rollers and holds them in the open position in the open, lifted position. Immediately after the delivery roller pair, a spinning nozzle for spinning the fiber bundle stretched in the drafting system is placed.

[0025] According to the invention, the delivery top roller is installed on the engaging delivery bottom roller. Thus, the engagement between the delivery top roller and its delivery bottom roller is very precisely defined. The two rollers do not shift relative to each other even when the drafting system opens or closes, so that no serial tolerance that causes inaccurate engagement between them occurs. Further, although the delivery top roller is loaded by the load carrier but not attached to the load carrier, the delivery top roller remains within the bearing when the load carrier pivots open, whereby the delivery top roller is always accurately positioned relative to the bottom roller and is guaranteed to be in a very good state, enabling very high-speed spinning at the spinning nozzle.

[0026] In a particularly advantageous embodiment of the present invention, the discharge top roller pair is received by a receiving fork incorporated into the draft system frame, similar to the discharge bottom cylinder bearing. The receiving fork is a slotted guide that secures the position of the discharge top roller relative to the discharge bottom cylinder, taking into account the change in the diameter of the top cylinder after the cover has been polished. While the load carrier is open, the discharge top roller remains on the draft system surface where the fiber bundle to be drafted is present.

[0027] The discharge top roller is held in a slotted guide and prevented from falling out by a retaining spring. The retaining spring is implemented to allow the top roller shaft to be attached to and removed from the slotted guide.

[0028] The top roller has a collar or recess on its axis, which aligns it axially. The collar or recess positions the top roller in the intended axial position on the slotted guide.

[0029] In the twin-unit configuration, two bearing receptacles for the left and right discharge bottom cylinders, along with two slotted guides, are integrated into the draft system frame. This ensures extremely precise alignment of the top roller and bottom cylinder. The spinning nozzle is also housed within the draft frame, ensuring that it is precisely positioned relative to the discharge top and bottom rollers.

[0030] When the carrier closes, the discharge top roller is preferably loaded by a spring element, particularly a leaf spring, which is received within the load carrier. Of course, spiral springs can also be used. Pneumatic or hydraulic loading is also possible.

[0031] The present invention is carried out in accordance with the above description, and the features mentioned can be carried out individually or in any combination.

[0032] Further advantages of the present invention are described in the following examples, each outlined below. [Brief explanation of the drawing]

[0033] [Figure 1] Figure 1 is a side view of a closed draft system according to the present invention. [Figure 2] Figure 2 shows the draft system shown in Figure 1 in its open state. [Figure 3] Figure 3 is a side view of the frame. [Figure 4] Figure 4 is a plan view of the frame shown in Figure 3. [Figure 5] Figure 5 is a plan view of the bearing of the discharge top roller. [Figure 6] Figure 6 is a side view showing a displaceable mounting device for the discharge top roller. [Figure 7] Figure 7 is a plan view showing a common displaceable mounting device for the discharge top roller. [Modes for carrying out the invention]

[0034] In the following descriptions of alternative embodiments, the same reference symbols are used for features that are identical and / or at least equivalent in design and / or operating mode compared to other embodiments. Unless a detailed description of an individual feature is repeated, its design and / or function corresponds to the design and function of the previously described feature. For the sake of clarity, reference numbers for components already described may not be inserted in the following figures.

[0035] The draft system 1 comprises a frame 2 positioned on the machine frame 3 of an air-jet spinning machine. On the frame 2 are displaceable bearing points 4 for an input bottom roller 5 and two intermediate bottom rollers 6. One of the intermediate bottom rollers 6 has a strap 7. A discharge bottom roller 8 is positioned behind the strap 7, and its bearing point 4 is fixed integrally to the frame 2 here. Each bottom roller 5, 6, and 8 is driven by a motor 9 and a drive belt 10. Each bottom roller 5, 6, and 8 has engaging top rollers 11, 12, and 13, and a strap 17 engages with the strap 7. The input bottom roller 5, together with the input top roller 11, forms an inlet roller pair 14, 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, together with the discharge top roller 13, forms a discharge roller pair 16. The spinning nozzle 18 is positioned on the frame 2 in a receptacle 19 following the discharge roller pair 16. The receptacle 19 can tilt the spinning nozzle 18 as needed to perform maintenance on the spinning nozzle 18. The spinning nozzle 18 is conformed to the peripheral shape of the discharge bottom roller 8 and the discharge top roller 13, thereby creating a flow that does not obstruct the fibers being conveyed through the draft system 1 and the spinning nozzle 18.

[0036] The top rollers 11 and 12 are positioned on the load carrier 20. The load carrier 20 can pivot via pivot bearings 21, thereby allowing the load carrier to move from a closed position, as shown herein, where the top rollers 11, 12, and 13 are positioned on the bottom rollers 5, 6, and 8, to the open position shown in Figure 2. In the closed position of the draft system 1 shown in Figure 1, the pressure element 22 exerts a compressive force on the top rollers 11, 12, and 13, forming a clamp line between the bottom rollers 5, 6, and 8 that engage with the top rollers 11, 12, and 13, where the fibers of the fiber bundle moving through the draft system 1 are clamped and pulled towards each other 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 the pressure element can be a pneumatic or hydraulic pressure element.

[0037] The top rollers 11 and 12 are attached to the load carrier 20 by retaining elements 23. The retaining elements 23 lift the top rollers 11 and 12, along with the strap 17, from the bottom rollers 5 and 6 and the engaging strap 7 when the load carrier 20 opens, i.e., pivots around the pivot bearing 21. In contrast, the discharge top roller 13 is not attached to the load carrier 20 with the retaining elements 23. Only a pressure element 22 is attached to the load carrier 20, pressing the discharge top roller 13 against the discharge bottom roller 8 when closed. A wide slotted guide 24 is installed on the load carrier 20 to roughly guide the discharge top roller 13 and the load carrier 20 when opening and closing, and the wide slotted guide loosely encompasses the axis of the discharge top roller 13, although it is not shown here. Therefore, when the load carrier 20 opens, the discharge top roller 13 is not lifted from its discharge bottom roller 8 and remains on top of it.

[0038] Related to this, Figure 2 shows the draft system 1 of Figure 1 in an open state. The load carrier 20 and pivot bearing 21 pivot to lift the top rollers 11, 12 and strap 17 from their bottom rollers 5, 6 and bottom strap 7. In this state, fiber bundles (not shown here) within the draft system 1 can be removed or inserted as needed. The discharge top roller 13 remains on its discharge bottom roller 8 and is therefore engaged with the spinning nozzle 18 very precisely. The discharge top roller 13 does not need 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, very precise and low-tolerance installation is possible.

[0039] Figure 2 shows that the pressure element 22 and the retaining element 2 remain connected to the top rollers 11 and 12. However, the pressure element 22, which applies a compressive force to the discharge top roller 13, detaches from the discharge top roller 13 and is lifted along with the load carrier 20. The pressure element 22 is surrounded by a wide slotted guide 24, which roughly guides the load carrier 20 with respect to the axis of the discharge top roller 13 in order to more securely fix the discharge top roller 13 and to ensure that the load carrier closes properly.

[0040] Figure 3 shows a side view of the frame 2 of Figures 1 and 2. A bearing point 4 for the discharge bottom roller 8 is fixedly connected to the frame 2. The bearing point 4 has an opening 25, within which the roller bearing (not shown) of the discharge bottom roller 8 can be placed. Furthermore, the stationary portions of the receptacle 19 and pivot bearing 21 are positioned on the frame 2.

[0041] The bearing 26 for the shaft 27 of the discharge top roller 13 is provided as a structural unit having bearing point 4 of the discharge bottom roller 8. The bearing 26 includes a slotted guide 28 that guides and precisely positions the shaft 27. Because the bearing 26 and bearing point 4 fix the slotted guide 28 to the frame 2 and further to the receptacle 19, the observed tolerance is small and the entire discharge roller pair 16 can be positioned relative to the spinning nozzle 18 such that the distance between the discharge roller pair 16 and the spinning nozzle 18 is constant and very small. This results in little to no turbulence when the fiber bundle is conveyed through the draft system 1 and the spinning nozzle 18.

[0042] Figure 4 shows a plan view of the frame 2 of the previous Figures 1, 2, and 3. The frame 2 is a component of a twin unit on which two draft systems 1 are arranged. The bottom rollers 5, 6, and 8 of the two draft systems 1 are equipped with independent individual drive units and can be operated independently of each other. The drive belt 10 (see Figure 1) is located, for example, in the internal space 29 of the frame 2. The frame 2 also includes guide rails 30, within which the bearing points 4 of the input bottom roller 5 and the intermediate bottom roller 6 are movable in the longitudinal direction. Thus, the distance between the bottom rollers 5, 6, and 8 can be adjusted relative to each other. The stationary portion of the pivot bearing 21 is located between the guide rails 30, on which the pivot bearing of the load carrier 20 is pivotably mounted. The load carrier 20 is responsible for loading the top rollers 11, 12, and 13 of both draft systems 1. The frame 2 further includes two bearing points 4 for the two discharge bottom rollers 13, which are fixedly connected to the frame 2. Similarly, two receptacles 19 are provided for two spinning nozzles 18, which engage with the two draft systems 1 of the frame 2.

[0043] The bearings 26 and slotted guides 28 are fixedly positioned at the respective bearing points 4 of the frame 2. This preferably forms a single integrated base for the bearing points 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 displaceable from one another. Thus, the bearings can be manufactured with great precision, resulting in a very tight and precise engagement between the discharge roller pair 16 and the spinning nozzle 18.

[0044] Figure 5 shows a plan view of the bearing of the discharge top roller 13. The frame 2, shown only partially here, forms the base of a twin unit having two parallel draft systems 1. Two bearing points 4 for the discharge bottom roller 8 are fixedly positioned on the frame 2. A bearing 26 for the discharge top roller 13, equipped with a slotted guide 28, is located on the bearing points 4. The slotted guide 28 guides the shaft 27, which, like a twin roller 31, has the discharge top roller 13 of each draft system 1 at both ends. In the area of ​​each bearing 26, a collar 32 is provided on the shaft 27. The collar 32 supports the shaft 27 on the bearing 26 and positions the twin roller 31 axially. This positions each discharge top roller 13 above the discharge bottom roller 8.

[0045] Furthermore, a retaining spring 33 is provided in the area of ​​bearing point 4. The retaining spring 33 ensures that the twin roller 31 or the discharge top roller 13 does not unintentionally detach from its bearing 26. To remove the twin roller 31 from the bearing 26, the retaining spring 33 must be loosened or bent so that the shaft 27 can be removed from the bearing 26 and its slotted guide 28.

[0046] Furthermore, Figure 5 shows how the shaft 27 is pressed against its discharge bottom roller 8 by the pressure element 22 of the load carrier 20. The wide slotted guide 24 is provided to roughly position the load carrier 20 relative to the shaft 27 of the frame 2 and the twin rollers 31. The slotted guide 24 loosely engages around the shaft 27 so that the pressure element 22 is properly positioned on the shaft 27, especially when the load carrier 20 is closed.

[0047] As can be seen particularly in Figure 5, the shaft 27, and therefore each discharge top roller 13, is positioned with great precision in the axial and radial directions, and the gap between the discharge top roller 13 and the spinning nozzle 18 can always be kept very small. This ensures particularly good spinning results when using the present invention.

[0048] Figure 6 is a side view showing a displaceable mounting device for the discharge top roller 13. The bearing 26, with its slot 28, is mounted separately from the bearing point 4 of the discharge bottom roller 8. The separation point is mounted as a bearing surface 34, along which the bearing 26 can be adjusted relative to the bearing point 4 and therefore to the spinning nozzle 18. The adjustment range is indicated by a double arrow V. After the position is properly adjusted, the bearing 26 is fixedly connected to the bearing point 4 using a screw 35.

[0049] Adjustment of the bearing 26 may be necessary when using discharge top rollers 13 of different diameters, for example, when it is necessary to polish the cover of the discharge top roller 13. Of course, the bearing 26 can also be mounted directly to the frame 2, either fixedly or movably. As shown here, the bearing surface 34 can be mounted at an angle to allow simultaneous horizontal and vertical adjustment. However, depending on the bearing surface of the bearing 26 and its mounting, it is also possible to adjust only horizontally and / or vertically. The important thing here is that the position of the discharge top roller 13 can be optimally adjusted with respect to the spinning nozzle 18.

[0050] Figure 7 shows a top view of a common displaceable bearing for twin rollers 31 having a common shaft 27 (Figure 5). Two bearings 26 are connected to each other by a connecting web 37 so that the shaft 27 can be adjusted and the two discharge top rollers 13 of the twin unit can be adjusted simultaneously. Thus the entire unit can move within the slot 36 according to the double arrow V and can be fixed in place using screws 35 in each case.

[0051] The present invention is not limited to the illustrated and described embodiments. Modifications within the scope of the claims are possible, and any combination of the described features is also possible, provided that it does not contradict the teachings of the independent claims, even if the aforementioned features are shown in different parts of the specification or claims or in different embodiments. [Explanation of symbols]

[0052] 1. Draft System 2 frames 3. Machine frame 4 bearing points 5. Insertion bottom roller 6. Intermediate bottom roller 7 straps 8 Discharge bottom roller 9 Engines 10 Drive belt 11. Input top roller 12 Intermediate top roller 13 Discharge top roller 14 Entrance roller 15 Intermediate Roller vs. 16 Discharge roller pair 17 Straps 18 Spinning nozzle 19 Receptacles 20 Road Carrier 21 Pivot bearings 22 Pressure elements 23 Retention elements 24 Wide Slotted Guides 25 Opening 26 bearings 27 axes 28-slot guide 29 Interior space 30 Guide Rails 31 Twin Roller 32 colors 33 Retaining spring 34 Bearing surface 35 screws 36 slots 37 Connect to the Web

Claims

1. A drafting system for drafting fiber bundles for an air-jet spinning machine, The frame (2) for the draft system (1), Equipped with multiple driveable bottom rollers (5, 6, 8), Each bottom roller (5, 6, 8) is installed at a bearing point (4) on the frame (2), Each bottom roller (5, 6, 8) engages with a top roller (11, 12, 13), and the bottom and top rollers (5, 6, 8, 11, 12, 13) form an inlet roller pair (14), at least one intermediate roller pair (15), and a discharge roller pair (16). The load carrier (20) is pivotably positioned on the pivot bearing (21) on the frame (2), The load carrier (20) includes a pressure element (22) for loading the top rollers (11, 12, 13) and a holding element (23) for holding and lifting the top rollers (11, 12) when the load carrier (20) pivots and opens. A draft system in which a receptacle (19) for a spinning nozzle (18) is positioned on the frame (2) in order to position the spinning nozzle (18) immediately after the discharge roller pair (16), The draft system is characterized in that the discharge top roller (13) is mounted on a bearing (26) connected to the bearing point (4) of the engaging discharge bottom roller (8), and the discharge top roller (13) is loaded by the load carrier (20), but is not attached to the load carrier (20), so that when the load carrier (20) pivots and opens, the discharge top roller remains inside the bearing (26).

2. The draft system according to claim 1, characterized in that the bearing (26) of the discharge top roller (13) is a slotted guide (28).

3. The draft system according to claim 1 or 2, characterized in that the pressure element (22) is a spring, particularly a leaf spring or a spiral spring, or a pneumatic or hydraulic pressure element.

4. The draft system according to any one of claims 1 to 3, characterized in that the load carrier (20) is provided with a wide slotted guide (24) for the discharge top roller (13).

5. The draft system according to any one of claims 1 to 4, characterized in that the shaft (27) of the discharge top roller (13) is provided with at least one collar (32) for axial positioning within the bearing (26).

6. The draft system according to any one of claims 1 to 5, characterized in that the shaft (27) of the discharge top roller (13) is held in the bearing (26) by a retaining device, particularly a retaining spring (33).

7. The draft system according to any one of claims 1 to 6, wherein the draft system (1) is arranged in a twin unit on the frame (2), the two draft systems (1) are equipped with independent drive devices, and the draft systems (1) are arranged substantially mirror-symmetrically with respect to each other.

8. The draft system according to claim 7, characterized in that at least the discharge top rollers (13) of the two draft systems (1) are implemented as twin rollers (31) having a common shaft (27).

9. The draft system according to claim 7 or 8, characterized in that the load carrier (20) loads the top rollers (11, 12, 13) of both draft systems (1) together.

10. The draft system according to any one of claims 1 to 9, characterized in that the bearing (26) of the discharge top roller (13) is adjustable with respect to the bearing point (4) of the discharge bottom roller (8) with which its position engages.

11. The draft system according to claim 8, characterized in that the bearings (26) of the discharge top roller (13), which are implemented as twin rollers (31) having a common shaft (27), are adjustable together.

12. A loading and unloading method for the draft system of an air-jet spinning machine having bottom and top rollers (5, 6, 8, 11, 12, 13), Each bottom roller (5, 6, 8) engages with a top roller (11, 12, 13), and the bottom and top rollers (5, 6, 8, 11, 12, 13) form an inlet roller pair (14), 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. The method involves positioning a spinning nozzle (18) for spinning the fiber bundles drawn by the draft system (1) immediately after the discharge roller pair (16), The discharge top roller (13) is located above the discharge bottom roller (8) with which it engages. The discharge top roller (13) is loaded by the load carrier (20), but is not attached to the load carrier (20), so when the load carrier (20) pivots and opens, the discharge top roller remains inside the bearing (26).

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