METHOD FOR OPERATING A CURLING DEVICE AND CURLING DEVICE

Description

[0001] The invention relates to a method for operating a crimping device according to the preamble of claim 1 and to a crimping device for crimping a fiber strand according to the preamble of claim 6.

[0002] Such crimping devices are particularly used in the production of staple fibers. Before a fiber strand is cut, the fibers of the fiber strand are crimped. For this purpose, the fibers of the fiber strand are guided through a nip formed between two driven rollers. The nip is followed by a so-called stuffer box, in which the fibers of the fiber strand are conveyed. To prevent the fibers from escaping from the nip at the end faces of the rollers, the nip is sealed at each end face of the rollers by a pressure plate. It is common practice to press the pressure plates against the end faces of the rollers with a contact force. Due to the relative movement between the rollers and the pressure plates, wear and tear inevitably occurs, as well as metal abrasion, which is absorbed by the fibers and is therefore undesirable.

[0003] To prevent such metal abrasion, a crimping device is known from DE 195 37 958 A, in which the printing plates are held against the end faces of the rollers by means of a pressure actuator and wherein a superimposed rotary drive causes the printing plates to rotate. Despite this rotation of the printing plates, wear is possible due to the pressure plates resting against the end faces of the rollers under pressure. In addition, heat development can be observed due to the relative movements between the printing plates and the end faces of the rollers, which leads to an increase in the temperature of the adjacent fiber strands. The friction required for wear and heating is not significantly reduced even by the rotation of the printing plates because the velocity vectors of the printing plates and the end faces of the rollers are not aligned.

[0004] In principle, other crimping devices are also known in the prior art in which a defined sealing gap is set between the end faces of the rollers and the pressure plate. For example, DE 102 43 203 A1 discloses a crimping device in which the pressure plates are each arranged on the end plates of the rollers via a side plate with a predefined sealing gap. The sealing gap can be adjusted using a fixing means. However, such preset sealing gaps between a pressure plate and the end faces of the rollers generally have the disadvantage that individual filaments of the fiber strands are pressed into the sealing gap. Although this prevents wear between the pressure plates and the rollers, it has the disadvantage that fibers are pressed from the roller gap into the sealing gap.

[0005] The document DE 36 21 479 A1 describes a stuffer box crimping device for crimping synthetic yarn sheets. It is intended to seal a pair of rollers at the sides by means of lateral elements of the stuffer box and pressure discs that are constantly pressed against the rollers. The contact pressure is regulated depending on the deflection of sensing elements, which can be formed by the side parts of the stuffer box.

[0006] Further devices of the known type are disclosed in the documents DE 195 37 958 C1 and US 3 800 373 A.

[0007] It is now an object of the invention to provide a method for operating a crimping device and a generic crimping device by means of which the crimping of a fiber strand takes place in such a way that as little wear as possible occurs between the rollers and the pressure plates and as little sealing gaps as possible are created.

[0008] This object is achieved according to the invention by a method for operating a crimping device having the features of claim 1 and by a crimping device having the features of claim 6.

[0009] Advantageous further developments of the invention are defined by the respective features and combinations of features of the subclaims.

[0010] The invention has the particular advantage that no contact force acts between the printing plates and the end faces of the rollers during operation of the crimping device. The printing plates are immediately fixed in a contact position in which there is almost no sealing gap by a clamp. For this purpose, the printing plates are briefly pressed against the end faces of the rollers at the start of the process and, once a contact position is reached, are held in place by a clamping force. For this purpose, the crimping device has a separate clamp actuator for each printing plate for clamping the printing plates, which can be controlled together with the pressure actuators by at least one control unit. In this way, after activation of the clamp actuators, which fix the printing plates in their respective contact positions, the pressure actuators can be deactivated. During operation, there is no longer any need to press the printing plates against the end faces of the rollers.

[0011] For this purpose, the printing plates are clamped with a radial clamping force in such a way that the printing plates remain in the contact position during operation. The compressive forces generated by the fiber strand inside the roller gap are absorbed by the clamping forces on the printing plates.

[0012] In order to be able to use the surfaces of the pressure plates evenly to seal the sealing gaps against the front faces of the rollers, the process variant in which each of the pressure plates is connected to a rotary drive and performs a superimposed rotation relative to the respective front face of the rollers in the contact position is particularly advantageous. This achieves a uniform load on the pressure plate.

[0013] For this purpose, the crimping device has rotary drives that are coupled to the printing plates so that the printing plates can rotate relative to the end faces of the rollers.

[0014] To guide the printing plates into the respective contact positions, the preferred process variant is one in which the printing plates are pressed axially against the front sides of the rollers using a pneumatically generated pressure force. No high forces are required, as the compressive forces occurring in the roller gap during operation are absorbed solely by the clamping forces acting on the printing plates. The pressure force serves only to adjust the gap-free printing plate position before the process begins.

[0015] To generate relatively high clamping forces, the printing plates are preferably held radially in the contact position with a hydraulically generated clamping force. This ensures that the printing plates remain in their contact positions during operation of the crimping device. Any sealing gaps that may develop during operation depend exclusively on the material of the components and their elastic modulus. In extreme cases, these gaps may only be a few micrometers.

[0016] The adjustment and fixation of the printing plates can preferably be achieved by a support piston that rests against the end face of one of the printing plates. The forces for adjusting the printing plates and clamping the printing plates can thus advantageously be generated directly on the support piston by the pressure actuator and the clamping actuator.

[0017] To enable rotation of the printing plates despite the clamping, the preferred embodiment of the crimping device is designed in which the support pistons each have a rotatable shaft section that is non-rotatably connected to the printing plates and coupled to the rotary drives. For example, the support pistons can be connected to the shaft sections by a bearing, which enables the transmission of the pressure forces.

[0018] In this respect, the crimping device according to the invention is particularly advantageous in the refinement in which one of the pressure actuators acts axially and one of the clamping actuators acts radially on a support piston that rests against a pressure plate. Thus, the pressure actuator and the clamping actuator can be advantageously integrated into a single structural unit that is associated with the pressure plates via a support piston.

[0019] The pressure actuator advantageously has a compressed air supply and the clamping actuator has a hydraulic supply.

[0020] The version in which the pressure actuator and the clamping actuator are integrated into a single housing is particularly compact. This makes the unit ideal for operation in the harsh environment of a fiber optic line.

[0021] The method according to the invention for operating a crimping device and the crimping device according to the invention thus offer the particular advantage that the fiber strands can be crimped and guided with high uniformity even in the edge region of the roll gap.

[0022] The method according to the invention for operating a crimping device is explained in more detail below using an embodiment of the crimping device according to the invention with reference to the attached figures.

[0023] They represent: Fig. 1 schematically shows a front view of a first embodiment of a crimping device according to the invention Fig. 2 schematically shows a side view of the embodiment of Fig. 1 Fig. 3 schematically shows a detail view of a further embodiment of the crimping device according to the invention. Fig. 4 schematically shows a front view of a further embodiment of a crimping device according to the invention. Fig. 5 schematically shows a detail view of a further embodiment of the crimping device according to the invention.

[0024] In the Fig. 1 and 2 A first embodiment of the crimping device according to the invention is shown schematically in several views. Fig. 1 shows the embodiment in a front view and in Fig. 2 A side view is shown. Only the components of a crimping device essential to the invention are shown.

[0025] The crimping device comprises two driven rollers 1.1 and 1.2, which are arranged in a machine frame (not shown here) and driven by at least one motor (also not shown here). The rollers 1.1 and 1.2 form a nip 2 between them.

[0026] As in the Fig. 2 As shown, a stuffer box 3 is assigned to the rolls 1.1 and 1.2 on an outlet side of the roll gap 2. The stuffer box 3 is delimited on both end faces of the rolls 1.1 and 1.2 by a side plate 4.1 and 4.2 respectively. Between the side plates 4.1 and 4.2 are arranged a base plate 3.1 and a top plate 3.2, which form the chamber inlet of the stuffer box 3 between them, parallel to the roll gap. The base plate 3.1 and the top plate 3.2 are assigned directly to the circumference of the rolls 1.1 and 1.2 on the inlet side of the stuffer box 3.

[0027] As can be seen particularly from the presentation in Fig. 1 As can be seen, the side plates 4.1 and 4.2 each have a pressure plate 5.1 and 5.2 in the area of ​​the roll gap 2. The pressure plate 5.1 is recessed in the side plate 4.1 and is designed to be axially movable. Accordingly, the pressure plate 5.2 is embedded in the side plate 4.2. The side plates 4.1 and 4.2 each have a recess 6.1 and 6.2 for this purpose. For the axial adjustment of the pressure plates 5.1 and 5.2, each of the pressure plates 5.1 and 5.2 is assigned a support piston 7.1 and 7.2. The support pistons 7.1 and 7.2 penetrate the side plates 4.1 and 4.2 and rest on the front sides of the pressure plates 5.1 and 5.2.

[0028] A pressure actuator 8.1 and a clamping actuator 9.1 act on a projecting end of the support piston 7.1. The pressure actuator 8.1 and the clamping actuator 9.1 are connected to a control unit 11.

[0029] On the opposite side of the roller gap, a second pressure actuator 8.2 and a second clamping actuator 9.2 act on the free projecting end of the support piston 7.2. The pressure actuator 8.2 and the clamping actuator 9.2 are also coupled to a control unit 11.

[0030] The pressure actuators 8.1 and 8.2 as well as the clamp actuators 9.1 and 9.2 are in Fig. 1 Only shown schematically. Electric, pneumatic, or hydraulic pressure actuators can be used for the pressure actuators 8.1 and 8.2, which generate an axially acting pressure force on the support pistons 7.1 and 7.2. Accordingly, the clamping actuators 9.1 and 9.2 could be formed by electric, pneumatic, or hydraulic clamping elements that generate a radially acting clamping force on the circumference of the support pistons 7.1 and 7.2.

[0031] For commissioning of the Fig. 1 and 2In the crimping device shown, the pressure plates 5.1 and 5.2 are first axially displaced synchronously by activation of the pressure actuators 8.1 and 8.2 by the control unit 11 and guided with a pressing force against the end faces 10.1 and 10.2 of the rollers 1.1 and 1.2. As soon as the pressure plates 5.1 and 5.2 have each reached the contact position, the clamping actuators 9.1 and 9.2 are activated via the control unit 11, so that the support pistons 7.1 and 7.2 are fixed in their current position by a clamping force on the circumference. The pressure plates 5.1 and 5.2 are thus held in their contact position against the end faces 10.1 and 10.2 of the rollers 1.1 and 1.2 by clamping. The pressure actuators 8.1 and 8.2 are deactivated so that no contact forces are applied, and the pressure plates 5.1 and 5.2 remain in their contact position without contact force. During operation, fiber strands are now fed to rollers 1.1 and 1.2. The fiber strands are wound through rollers 1.1 and 1.2.2 is drawn into the roll gap 2 and guided into the adjacent compression chamber 3. This creates high operating pressures within the roll gap, which act against the pressure plates 5.1 and 5.2. These compressive forces are absorbed by the clamping forces on the support pistons 7.1 and 7.2. This prevents any sealing gaps from forming.

[0032] In the Fig. 1 schematically illustrated crimping device, the pressure actuators 8.1 and 8.2 as well as the clamping actuators 9.1 and 9.2 can also be advantageously controlled by separate control units, which are Fig. 1 shown in dashed lines and marked with reference numerals 11.1 and 11.2. Thus, the adjustment of the pressure plates 5.1 and 5.2 and the clamping of the pressure plates 5.1 and 5.2 on both ends of the rollers 1.1 and 1.2 can be carried out independently of each other.

[0033] The connection of clamp actuators 9.1 and 9.2 and pressure actuators 8.1 and 8.2 to support pistons 7.1 and 7.2 is also exemplary. Depending on the design of the pressure actuators and clamp actuators, these could also act directly on the pressure plates and, for example, be partially integrated into the side plates.

[0034] In practice, however, it has proven useful to integrate the pressure actuator and the clamping actuator into a single unit in order to achieve the most compact design possible on the crimping device. Fig. 3 schematically shows a cross-sectional view of a possible embodiment of the crimping device in a detail. Fig. 3 In the embodiment shown, the pressure actuator 8.1 and the clamping actuator 9.1 are integrated in a housing 12. A support piston 7.1 is guided in a housing bore 20 in the housing 12. The housing bore 20 is closed at one end and connected to a compressed air supply connection 13 formed on the housing 12. An air chamber 15 is formed below the support piston 7.1 within the housing bore 20. A return spring 18 is clamped inside between the support piston 7.1 and the housing 12.

[0035] On the circumference of the support piston 7.1, a clamping bush 17 is held within the housing 12 in a recess 21 of the housing bore 20 between two seals 19. The seals 19 define the recess 21 and act between the housing 12 and the support piston 7.1. A pressure chamber 16 is formed on the circumference of the clamping bush 17, which communicates with a hydraulic supply connection 14 in the housing 12.

[0036] The support piston 7.1 has a projecting end that rests against an end face of the pressure plate 5.1.

[0037] In the Fig. 3 In the illustrated embodiment, the pressure actuator 8.1 is activated via the compressed air supply connection 13. For this purpose, compressed air is fed into the air chamber 15, which presses the support piston 7.1 against the pressure plate 5.1, so that the pressure plate 5.1 is guided in a contact position against the end faces 10.1 and 10.2 of the rollers 1.1 and 1.2.

[0038] The clamp actuator 9.1 is activated via the hydraulic supply connection 14. For this purpose, high-pressure hydraulic fluid is fed into the pressure chamber 16, which clamps the support piston 7.1 via the clamping bushing 17. As soon as the support piston 7.1 is clamped by the clamp actuator 9.1, the pressure actuator 8.1 is deactivated by depressurizing the air supply connection 13. The pressure plate 5.1 in the side plate 4.1 is now ready for operation.

[0039] In the Fig. 3 Only one of the pressure plates 4.1 is shown. Preferably, the pressure actuators 8.2 and clamping actuators 9.2 associated with the pressure plate 4.2 are identical to the embodiment shown in Fig. 3 Synchronous or asynchronous control of the pressure actuators 8.1 and 8.2 and the clamp actuators 9.1 and 9.2 is possible.

[0040] In the Fig. 4 A further embodiment of the crimping device according to the invention is shown schematically in a front view. The embodiment according to Fig. 4 is essentially identical to the embodiment according to Fig. 1 and 2 , so that only the differences are explained below to avoid repetition and otherwise reference is made to the above description.

[0041] In the Fig. 4 In the illustrated embodiment, separate rotary drives 22.1 and 22.2 are assigned to the pressure plates 5.1 and 5.2 resting on the end faces of the rolls 1.1 and 1.2. The rotary drives 22.1 and 22.2 are connected to a control device 11. The control device is also connected to the pressure actuators 8.1 and 8.2 as well as to the clamping actuators 9.1 and 9.2 in order to guide and fix the pressure plates 5.1 and 5.2 into a respective contact position at the start of the process. As soon as the pressure plates 5.1 and 5.2 are fixed in the contact position, the rotary drives 22.1 and 22.2 are activated via the control unit 11 in order to rotate the pressure plates 5.1 and 5.2 relative to the end faces 10.1 and 10.2 of the rolls 1.1 and 1.2.

[0042] To drive the pressure plates 5.1 and 5.2 to rotate, the support pistons 7.1 and 7.2, which interact with the pressure actuators 8.1 and 8.2 and the clamping actuators 9.1 and 9.2, are designed in two parts. Thus, each of the support pistons 7.1 and 7.2 has a shaft section 23.1 and 23.2 at the end facing the pressure plates 5.1 and 5.2, which is rotatably mounted on the support pistons 7.1 and 7.2. In this respect, the rotary drives 22.1 and 22.2 act on the shaft sections 23.1 and 23.2 of the support pistons 7.1 and 7.2. The shaft sections 23.1 and 23.2 are connected to the respective pressure plate 5.1 and 5.2 in a rotationally fixed manner, which is preferably designed with a positive fit.

[0043] The Fig. 4 The illustrated embodiment thus has the particular advantage that the position of the pressure plates 5.1 and 5.2 changes relative to the end faces 10.1 and 10.2 of the rollers 1.1 and 1.2. This results in a more even load on the pressure plates 5.1 and 5.2. The rotary drives 22.1 and 22.2 can be implemented by electrical, hydraulic, or pneumatic means.

[0044] In the Fig. 5 A further embodiment of the crimping device according to the invention is shown schematically in a detail view. Fig. 5 The embodiment shown is identical to the one in Fig. 3 The embodiment shown is similar, so reference is first made to the above description, and otherwise only the differences are explained. Components with the same function have, of course, been given identical reference numerals.

[0045] In the Fig. 5 In the illustrated embodiment, the pressure actuators and clamping actuators are each integrated into a structural unit. The structural unit acts on a support piston 7.1, which is guided in a housing 12. A shaft section 23.1 is formed at the projecting end of the support piston 7.1, which is held on the support piston 7.1 via a bearing 27. The bearing 27 between the shaft section 23.1 and the support piston 7.1 is designed such that an axial force is transmitted unhindered to the shaft section 23.1. The free end of the shaft section 23.1 is positively and rotationally fixedly coupled to the pressure plate 5.1.

[0046] In order to rotate the shaft section 23.1 and thus the pressure plate 5.1, a worm gear 24 is provided, which is connected via a worm shaft 25 to a toothing on the shaft section 23.1. The worm shaft 25 is driven in rotation by a drive 26. The drive 26 is shown only schematically here and could, for example, be implemented by electrical, pneumatic, or hydraulic means. For example, a drive of the shaft section 23.1 can be implemented hydraulically in such a way that the worm shaft 25 is driven in an oscillating manner via a hydraulic actuator. The connection between the shaft section 23.1 and the worm gear 24 has a freewheel, so that the rotary movement of the worm shaft 25 is transmitted to the shaft section 23.1 in only one direction of rotation.

[0047] The function is identical to the above-mentioned embodiment according to Fig. 4As soon as the pressure plate 5.1 is positioned and secured in its contact position against the end faces 10.1 and 10.2 of the rollers 1.1 and 1.2 by the pressure actuator and clamping actuator, the drive 26 is activated by the control unit (not shown here). In this respect, the pressure plate 5.1 performs a relative movement to the rollers 1.1 and 1.2.

[0048] The crimping device according to the invention is preferably used in a plant for staple fiber production, by means of which very high-quality staple fiber can be produced without frictional wear due to the advantages of the tightness of the sealing gaps.

Claims

1. Method for operating a crimping apparatus with two driven crimping rollers, by way of which a fibre strand is conveyed through a roller nip into a stuffer box, and in which method the roller nip is sealed on the front sides of the rollers by way of pressure plates, characterized in that, at a process beginning, the pressure plates are briefly pressed actively onto the front sides of the rollers and, after a contact position is reached, are held by way of in each case one clamping force.

2. Method according to Claim 1, characterized in that each of the pressure plates is clamped by way of a radially acting clamping force in such a way that the pressure plate remains in the contact position.

3. Method according to Claim 1 or 2, characterized in that each of the pressure plates is connected to in each case one rotary drive and carries out a superimposed rotation relative to the relevant front side of the rollers in the contact position.

4. Method according to one of Claims 1 to 3, characterized in that each of the pressure plates is pressed axially onto the front sides of the rollers by way of a pneumatically generated pressure force.

5. Method according to one of Claims 1 to 4, characterized in that each of the pressure plates is clamped radially in the contact position by way of a hydraulically generated clamping force.

6. Method according to one of Claims 1 to 54, characterized in that one of the pressure actuators and one of the clamping actuators act on a support piston which bears against a front side of the pressure plate.

7. Crimping apparatus for crimping a fibre strand with at least two driven rollers (1.1, 1.2) which form a roller nip (2) between them, with a stuffer box (3) which is assigned to the roller nip (2), and with two pressure plates (4.1, 4.2) which bear against the front sides (10.1, 10.2) of the rollers (1.1, 1.2) in order to seal the roller nip (2), each of which pressure plates is assigned a pressure actuator (8.1, 8.2) for pressing on the pressure plates (4.1, 4.2), characterized in that each of the pressure plates (4.1, 4.2) is additionally assigned in each case one clamping actuator (9.1, 9.2) for clamping the pressure plate (4.1, 4.2), and in that at least one control unit (11) is provided for controlling the pressure actuators (8.1, 8.2) and the clamping actuators (9.1, 9.2).

8. Crimping apparatus according to Claim 7, characterized in that the pressure plates (4.1, 4.2) can be pressed into in each case one contact position on the front sides (10.1, 10.2) of the rollers (1.1, 1.2) by way of a brief activation of the pressure actuators (8.1, 8.2).

9. Crimping apparatus according to Claim 8, characterized in that the pressure plates (4.1, 4.2) can be held in the contact positions during operation by way of an activation of the clamping actuators (9.1, 9.4).

10. Crimping apparatus according to one of Claims 7 to 9, characterized in that each of the pressure plates (4.1, 4.2) is additionally assigned in each case one rotary drive (22.1, 22.2), which rotary drives are connected to the control unit (11).

11. Crimping apparatus according to one of Claims 7 to 10, characterized in that one of the pressure actuators (8.1, 8.2) acts axially and one of the clamping actuators (9.1, 9.2) acts radially on a support piston (7.1, 7.2) which bears against one of the pressure plates (4.1, 4.2).

12. Crimping apparatus according to Claim 11, characterized in that the support pistons (7.1, 7.2) each have a rotatable shaft portion (23.1, 23.2), which shaft portions are connected fixedly to the pressure plates (4.1, 4.2) for conjoint rotation and are coupled to the rotary drives (22.1, 22.2).

13. Crimping apparatus according to Claim 12, characterized in that the pressure actuator (8.1, 8.2) is connected to a compressed air supply (13), and the clamping actuator (9.1, 9.2) is connected to a hydraulic supply (14).

14. Crimping apparatus according to Claim 13, characterized in that the pressure actuator (8.1, 8.2) and the clamping actuator (9.1, 9.2) are of integrated configuration in a housing (12).