CN113795617A

CN113795617A - Separating roller unit with a device for pressure rollers of a separating roller pair of a combing machine

Info

Publication number: CN113795617A
Application number: CN202080034183.2A
Authority: CN
Inventors: D·博梅尔
Original assignee: Maschinenfabrik Rieter AG
Current assignee: Maschinenfabrik Rieter AG
Priority date: 2019-05-09
Filing date: 2020-04-30
Publication date: 2021-12-14
Anticipated expiration: 2040-04-30
Also published as: EP3966373A1; WO2020225664A1; CN113795617B; CH716167A1; EP3966373B1

Abstract

The invention relates to a separating roller unit with a device for pressure rollers of a separating roller pair of a combing machine, comprising: a roller pair (20 a, 20 b) which is composed of a separating roller (22 a) and a pressure roller (24 a) that can rotate in the combing machine; a pressing device (26 a, 26 b) for pressing a pressure roller (24 a) of the roller pair (20 a) and a separating roller (22 a) against one another, wherein the pressure roller (24 a) is pressurized via the pressing device (26 a) and the pressing device (26 a) is connected to a compressed air connection (52). According to the invention, the compressed air connection (52) is connected to a pressure regulator (54) which is designed in such a way that a corresponding pressure for the pressure drum (24 a) for pressing against the separating drum (22 a) can be set as a function of a predefined rotational speed of the combing machine.

Description

Separating roller unit with a device for pressure rollers of a separating roller pair of a combing machine

Technical Field

The invention relates to a separating roller unit having a device for pressure rollers of a pair of separating rollers of a combing machine, comprising: at least one roller pair consisting of a separation roller and a pressure roller which can rotate in the combing machine by means of a reciprocating step motion; at least one pressing device for pressing the pressure roller and the separating roller of the at least one roller pair against one another, wherein the pressure roller is pressurized by the pressing device and the pressing device is connected to a pressure setting device.

Background

In conventional combing machines, as is known from DE 4039050 a1, a separating roller unit is used, which has a first and a second roller pair. These cylinder pairs consist of a separating cylinder and a pressure cylinder, respectively, which can be rotated in the combing machine by means of a reciprocating step motion. The separator roller unit further comprises a pressing device for pressing the pressure roller and the separator roller of each of said roller pairs against each other. In the known separating drum unit, the separating drum and the pressure drum of each drum pair are pressed against one another by a pressing device with an equally large force, wherein a pressure setting device is provided for this purpose. The known pressure roller is designed to set a pressure of approximately 6.5bar with a pressure setting device in a standardized manner.

With the background that the separating cylinder is usually grooved and made of steel and the pressure cylinder is likewise made of metal and provided with a coating made of a rubber-elastic material, the cylinder is comparatively heavy and has a large moment of inertia. This results in a high load on the drive of the combing machine, which means that the separating cylinders of each cylinder pair must rotate back and forth during each combing cycle of the combing machine with a reciprocating step movement. This situation leads in a disadvantageous manner, in particular at high rotational speeds of the combing machine (greater than 600 KS/min), to inhomogeneities in the combed nonwoven due to the different moments of inertia of the pressure roller and the separating roller during the welding process.

In particular, the different moments of inertia of each roller pair causes slippage between the pressure roller and the separating roller, which has a significant negative effect on the formation of the nonwoven, in particular during the welding of the combed nonwoven. This slippage leads to a tolerance error between the rotational speed of the pressure roller and the rotational speed of the separating roller, which is produced via the tow and which, for example, can be in the range of up to 25% in the case of a combing cycle number of 650KS/min and a pressing pressure of 5bar applied with the pressing device. This tolerance in the rotational speed between the pressure roller and the separating roller is no longer acceptable for the spinning mill owner, since this is directly related to the quality of the carded combed nonwoven.

Disclosure of Invention

The object of the present invention is therefore to provide a separating roller unit with a device for the pressure rollers of a separating roller pair of a combing machine, which allows a welding process with a separating roller pair of a combing machine to be set such that the quality of the combed nonwoven is acceptable even at high numbers of combing cycles.

This object is achieved by a detaching cylinder unit having a device for pressing cylinders of a detaching cylinder pair of a combing machine, having the features of independent claim 1.

A separating roller unit having a device for pressure rollers of a separating roller pair of a combing machine is proposed, having: at least a first roller pair, which is composed of a first separation roller and a first pressure roller that can rotate in the combing machine with reciprocating step motion; at least one pressing device for pressing a first pressure roller and a first separating roller of the at least first roller pair against one another, wherein the first pressure roller is pressurized by the pressing device and the pressing device is connected to a pressure connection. According to the invention, the pressure connection is connected to a pressure regulator, which is designed in such a way that, depending on the predefined rotational speed of the combing machine, a corresponding pressure can be set for the first pressure roller in order to press it against the first separating roller. The use of a pressure regulator for setting the pressure acting on the first pressure roller of the first roller pair relative to the first separating roller has the advantageous effect that the different moments of inertia between the first pressure roller and the first separating roller can be handled as a function of the rotational speed of the combing machine. The settable pressure thus prevents an excessive deviation between the rotational speed of the first pressure roller and the rotational speed of the first separating roller, since the pressure is set via the pressure regulator in such a way that the drag exerted by the first separating roller on the first pressure roller does not lead to a large rotational speed deviation, so that the welding process for producing combed nonwovens is greatly improved compared to separating roller units in which the pressure via the pressure device is constantly maintained at the same pressure level regardless of the set rotational speed of the combing machine. It is generally known in this connection that the welding process is carried out in a combing machine in such a way that: the separating drum executes a reciprocating movement via a transmission of the combing machine, wherein the individual fiber groups combed out via the circular comb are laid on top of each other in a roof-tile-like manner during the welding process via a drum composed of a pressure drum and the separating drum and are welded.

Preferably the pressure regulator comprises at least one electrically controllable pressure valve. The electrically controllable pressure valve is designed to throttle the system pressure of the pressure line and thus to transmit a reduced pressure to the pressure device. The pressure regulator has the task here of controlling the pressure valve such that a stepless pressure setting for the first pressure roller of the first roller pair can be achieved.

It should be mentioned at this point that the pressure regulator according to the invention can of course also be adjusted manually in order to set the desired pressure acting on the pressure roller, wherein such manual use is particularly inaccurate and involves the risk of mechanical overloading of the component.

Furthermore, the pressure regulator preferably sets a corresponding pressure between approximately 210N and approximately 642N as a function of the rotational speed of the combing machine. This preferred pressure for the pressure rollers allows a practically usable adaptation of the pressure ratio of the roller pair to the rotational speed of the combing machine by means of the pressure regulator.

In particular, it is preferred that the predefined rotational speed of the combing machine is at least approximately linearly dependent on the settable pressure for the first pressure roller. The linear correlation of the set rotational speed of the combing machine with the pressure required for the first pressure roller has the advantageous effect that the pressure regulator can set the pressure particularly simply and reproducibly with respect to the actual rotational speed of the combing machine. In this way, it is achieved that the rotational speed deviations of the pressure drum and the separating drum due to different moments of inertia are kept as small as possible.

Furthermore, the rotational speed of the combing machine is preferably between 400KS/min and 700 KS/min. It has proven particularly advantageous if the pressure regulator sets a pressure of between approximately 210N and approximately 214N, particularly preferably approximately 212N, at a combing speed of 400KS/min, a pressure of between approximately 420N and approximately 428N, particularly preferably approximately 424N, at a combing speed of 550KS/min, and a pressure of between approximately 630N and approximately 640N, particularly preferably approximately 636N, at a combing speed of 700 KS/min.

Furthermore, it is preferred that the slip between the first pressure roller and the first separating roller with a maximum tolerance of 3.0% can be set as a function of a predefined rotational speed of the combing machine in conjunction with a corresponding pressure. In this context, slippage represents a rotational speed difference between the first separating cylinder and the first pressure cylinder of the first cylinder pair, which rotational speed difference is caused by the different moments of inertia of the two components of the first cylinder pair in combination with the rotational speed of the combing machine. Thus, the herein mentioned slip is a mechanical interaction of two rotating members, wherein the slip becomes large as soon as the friction or interaction force between the two members becomes too small. Explained physically in this way, with a constant pressing force of 3bar with reference to a pressure roller with a conventional piston diameter of 26mm, the pressing force exerted by the pressure roller on the separating roller is so small with a high number of combing cycles, for example 600KS/min, that the separating roller rotates significantly faster than the pressure roller, as a result of which a considerable speed difference between the two components occurs, which causes slippage. Experiments have shown that the tolerance between the cylinder pairs is 55% at a pressure of 3bar and a combing duty cycle of 600 KS/min. Thus, the higher the pressure onto the pressure roller, the smaller the tolerance for slippage of the roller pair.

In a particularly preferred manner, the control unit is connected to the pressure regulator and has a data memory in which a data set is stored between a predetermined rotational speed of the combing machine and the corresponding pressure for a tolerance of 3.0% for slippage, so that the control unit sets the correct pressure for the first pressure roller via the pressure regulator as a function of the set rotational speed of the combing machine. It has proven to be advantageous if the slip between the pressure roller and the separating roller is in the tolerance range of 0.1% to a maximum of 3.0%, since the quality in the formation of the fibrous nonwoven is still acceptable in this tolerance range. The tolerance increases approximately exponentially as a function of the rotational speed with a constant set pressure, so that this approximately exponential tolerance can be compensated for by the negative influence of the slip only by the variable adaptation of the pressure regulator according to the invention.

Furthermore, a rotational angle sensor is preferably provided, which monitors the rotational speed of the combing machine and transmits it to the control unit in order to set the correct pressure for the first pressure roller via the pressure regulator as a function of a predefined rotational speed of the combing machine. The electrical connection of the rotation angle sensor, the pressure regulator and the control unit enables an optimum regulation of the pressure roller as a function of the rotational speed of the combing machine.

In particular, the pressure device preferably has a first piston, which can be acted upon by a pressure medium, preferably air, for the first pressure drum, wherein the first piston is connected to the compressed air connection via a pressure regulator. The shape of the pressure regulator has the advantageous effect that the control of the pressure can be defined via the cross section of the piston, wherein the control unit controls an electrically controllable pressure valve for the pressure medium via the pressure regulator, which pressure medium is used for loading the piston. The pressure medium is preferably compressed air which is supplied by a compressed air line and is transferred in a controlled manner to the piston via an electrically controllable pressure valve in order to generate the desired pressure.

Furthermore, it is preferred that the first piston has a diameter which is configured such that a pressure of between approximately 210N and approximately 640N for the first pressure drum can be set via the pressure regulator. This has the advantageous effect that the pressure roller has an optimum contact pressure for obtaining a good welded connection of the carded fibre assembly depending on the rotational speed of the combing machine. With reference to the claimed values for the minimum pressure and the maximum pressure according to the rotation speed of the combing machine, a deviation of the pressure value of +/-1.0% is considered as the claimed value range.

Preferably, the first piston has a diameter of about 30mm to about 38mm, preferably about 32 mm. In this way, it is advantageously achieved that the desired pressure acting on the first pressure roller is set, in which case a system pressure range of approximately 6.9bar is not even approached. In this way, using only a small part of the system pressure for the desired pressure is achieved without problems with the claimed embodiment of the piston. Furthermore, this is in contrast to conventional pistons, in which the piston diameter is in the range of 26mm and therefore the first pressure cylinder already requires a system pressure of approximately 7bar at an average number of combing cycles of 550KS/min in order to apply the desired pressure of approximately 500N. It should be mentioned at this point that the manual adjustment of the pressure for a pressure roller with the above-claimed piston geometry entails the risk that a mechanical overload of the piston can occur particularly quickly, since the user is accustomed to setting to 6.5bar according to a conventional procedure, which can lead to a comparatively high pressure on the piston. The use of the above-claimed piston geometry for the pressure roller is thus achieved in a reliable manner and method, in particular with the pressure regulator according to the invention, since a particularly accurate setting of the pressure regulator is achieved in a preferred manner via the control unit in conjunction with the pressure valve.

Preferably, a second cylinder pair is provided, which consists of a second separating cylinder, which can be rotated in a reciprocating movement in the combing machine, and a second pressure cylinder, wherein the second cylinder pair is connected downstream of the first cylinder pair in the transport direction of the fibrous nonwoven. The second pair of rollers is connected downstream of the first pair of rollers, as seen in the transport direction of the fibrous nonwoven, and accordingly guides the fibre groups that have been carded and are welded together there to the transport rollers connected downstream in a known manner.

In particular, the respective pressure device is preferably designed to apply a first pressure to a first pressure roller of the first roller pair and a second pressure to a second pressure roller of the second roller pair via a pressure regulator, the second pressure being greater than the first pressure depending on the rotational speed of the combing machine. The control unit enables the setting of the pressure regulator for a larger second pressure relative to a smaller first pressure in order to obtain a regular combed nonwoven with smooth edges in an advantageous manner. Since the corresponding pressure is set according to the rotating speed of the combing machine, the corresponding high-quality combed non-woven fabric can be set for the combing work circulation times of 400KS/min to 700KS/min of the combing machine without any problem.

Preferably, the second pressure is at least 10% greater than the first pressure. In this way, the difference in acceleration between the two cylinder pairs, which is caused by the different torques between the respective pressure cylinder and the respective separation cylinder of each respective cylinder pair, can be optimally compensated for in order to maintain the quality of the combed nonwoven. It should be mentioned at this point that, in particular, possible causes for different accelerations between two adjacent roller pairs may arise as a result of the fact that the first roller pair facing the pliers has a further or altered acceleration in the interaction with the pressure roller as a result of the reciprocating step movement of the first separating roller, compared to the second roller pair connected downstream.

Alternatively, the setting of different pressures for the first pressure drum and the second pressure drum is also effected by the dimensioning or rather the changed diameter of the first piston relative to the second piston, wherein in this embodiment only one pressure regulator suffices which transmits the same system pressure in the form of air to the respective differently dimensioned pistons and thus generates different first pressures relative to the larger second pressures, which act on the respective pressure drums.

The invention further relates to a combing machine having a separating cylinder unit according to the invention.

Drawings

Wherein:

fig. 1 shows a side view of parts of a combing head with a separating roller unit comprising two roller pairs;

FIG. 2 illustrates a conventional adjustment of a circular comb and separation cylinder unit;

FIG. 3 shows a schematic representation of the roller pair according to FIG. 1 with a separating roller movement and a pressure roller movement at constant nip force and different numbers of combing cycles;

FIG. 4 shows a schematic diagram of the tolerance of the cylinder pair according to FIG. 3 depending on the number of different combing work cycles;

fig. 5 shows the regulation of the contact pressure of the pressure roller according to fig. 1 via a pressure regulator according to the invention and a control unit for monitoring the rotational speed of the circular comb;

FIG. 6 shows a graphical representation of the tolerance of the cylinder pair according to FIG. 1 at different nip forces and different numbers of combing cycles;

FIG. 7 shows a schematic of the tolerance of the cylinder pair with respect to pressure onto the pressure cylinders according to the number of combing work cycles;

FIG. 8 shows a schematic diagram of the pressure onto the pressure rollers according to the number of combing work cycles for a tolerance of 3% of the roller pair according to FIG. 7; and

fig. 9 shows a side view of parts of a combing head with a further separating roller unit.

Detailed Description

Fig. 1 shows a purely schematic enlarged section of parts of a combing head 10 of a combing machine, with an oscillating nipper 12 comprising an upper nipper 14 and a lower nipper 16. The pliers 12 are shown in the forward position with the drum unit 18 separated. The separation roller unit 18 comprises in this example two

roller pairs

20a, 20b arranged parallel to each other. The first cylinder pair 20a adjacent to the nipper 12 is formed by a first separating cylinder 22a and a first pressure cylinder 24a, and the second cylinder pair 22b, which is further away from the nipper 12 in the transport direction of the combed nonwoven, is formed by a second separating cylinder 22b and a second pressure cylinder 24 b.

In operation, the gripper 12 is in the rear position in a known manner and method, wherein the fiber strand is clamped securely at the clamping point between the lower gripper plate 16 and the upper gripper plate 14 and is combed out by a rotating circular comb (not shown).

The nippers 12 are then moved into the forward position as shown in fig. 1 and opened, the separating

cylinders

22a, 22b being rotated by a drive (not shown) contained in the combing machine in the clockwise direction by a predetermined angle, so that the rear end of the previously formed combed nonwoven comes out of the clamping position of the first cylinder pair 20a and the front end of the fiber bundle, which is located on the lower nipper plate 16 and combed out with the circular comb, rests on said rear end in a roof-like or scale-like manner. The separating

rollers

22a, 22b are then rotated through a second predetermined greater angle in the counterclockwise direction to grasp, weld and separate the fiber bundle via the

roller pair

20a, 20 b.

The separating drum unit 18 in this example comprises a separate

pressing device

26a or 26b for each

drum pair

20a, 20b, respectively, for pressing the separating

drum

22a or 22b and the

pressure drum

24a or 24b against one another. Each

pressing device

26a or 26b comprises a

bearing support

28a or 28b for a

respective bearing

30a or 30b of the two

pressure rollers

24a or 24 b. The block 32 comprises for each of the bearing supports 28a or 28b a

separate piston

34a or 34b, respectively, on whose

piston rod

36a or 36b the associated

bearing support

28a or 28b is fastened, wherein the

respective piston

34a or 34b is guided displaceably in the block 32, which is fixed in operation relative to the machine frame. The block 32 comprises, above the upper end of the

respective piston

34a or 34b, a

respective comb

38a or 38b which, in operation, is supplied with compressed air through a duct, not shown, in order to push the

respective piston

34a or 34b and thus the

respective bearing bracket

28a or 28b downwards and thus to press the

respective pressure drum

24a or 24b against the

respective separating drum

22a or 22b with a pressure defined via the diameter 40 of the piston 34. The first piston 34a and the second piston 34b have the same diameter of about 32mm in this embodiment.

Fig. 2 shows a purely schematic conventional control device 42 for the separating drum unit 18 according to fig. 1 for producing a known reciprocating step movement of the separating drum by means of a first drive motor 44 and for the circular comb 46 for producing a rotary movement by means of a second drive motor 48, wherein the two

drive motors

44, 48 are coordinated with one another by means of a control unit 50.

It can also be seen from fig. 2 that the compressed air connection 52 for the pressure drum of the separating drum unit 18 as described in fig. 1 is directly connected to the respective piston (indicated by means of two arrows), so that a system pressure of approximately 7bar acts in the form of compressed air on the piston of the pressure drum unfiltered via the compressed air connection. In the case of the known pressure roller, the diameter of the piston in the known separating roller unit 18 is of the order of magnitude of approximately 26mm, so that a constant pressing force in the sense of a pressure of approximately 495N presses the pressure roller against the separating roller with a system pressure of approximately 7 bar.

Simultaneously with the constant contact pressure of 495N exerted by the pressure roller on the separating roller, a reciprocating step movement is carried out for the separating roller via the first drive motor 44, in order to be able to achieve roof tile-like welding of the fibre groups combed out by the circular comb 46 with the roller pair. What is known as a dragging of the pressure roller by the rotating movement of the separating roller occurs in this case, wherein the separating roller is actively rotated via the drive motor 44 and the pressure roller is passively rotated together. Furthermore, the carded fiber fleece is clamped in a shingled manner between the roller pair and the two rollers are pressed against one another via a constant contact pressure of 495N, wherein in this way the quality of the welded fiber nonwoven is defined in the case of conventional combing machines.

In this connection, it is to be defined that the drag exerted by the separating drum on the pressure drum is generated in that the rotary movement of the separating drum generates a counter force which acts counter to the constant contact pressure of the pressure drum.

Fig. 3 shows the cylinder stroke of the separating cylinder ARZ (bold solid black line) and the cylinder stroke of the pressure cylinder DRZ (solid black line) in each case in relation to the machine index of each combing cycle. Fig. 3 also shows the cylinder stroke of pressure cylinder DRZ as a function of the number of combing work cycles for different settings between 350KS/min and 700 KS/min.

Looking in detail at fig. 3, the first part of the drum stroke of the separation drum ARZ is a predetermined angle in the clockwise direction (see Y-axis from 0mm to-57 mm), then at-57 mm there occurs a reversal of the drum stroke of the separation drum ARZ in the counterclockwise direction by a second, larger angle, which is predetermined, linearly rising to 10mm, and then at 26mm there occurs a plateau. This roller path profile is typically implemented for the separating rollers on a combing machine with a so-called reciprocating step motion, so that the individual fiber groups combed with the circular and fixed combs are shingled on top of each other and can be welded to each other with at least the first roller pair according to fig. 1 with sufficient contact pressure (F = 495N). The cylinder stroke of the pressure cylinder DRZ runs in the circumferential stroke direction, which is exactly reversed for each combing cycle, simultaneously with the cylinder stroke of the separating cylinder ARZ, corresponding to the cylinder stroke curve of the separating cylinder ARZ.

The welding process with the roller pair, as shown in fig. 3, is carried out in the range of 10mm to 26mm and a machine index of 24 to 40, that is to say in the range in which the separating roller is driven in the counterclockwise direction and the pressing force for the stability of the welded fibrous nonwoven is obtained via the pressure roller.

According to the bold solid black line with the mark ARZ, the cylinder stroke of the detaching cylinder ARZ at a combing duty cycle number of about 320KS/min and a constant pressing force of 495N is exactly the cylinder stroke of the reversal of the pressure cylinder DRZ shown as a solid black line. Accordingly, the cylinder stroke of the separation cylinder and the cylinder stroke of the pressure cylinder are equal in value at about 320KS/min and 495N.

At a constant contact pressure of 495N, it is evident from fig. 3 that the roller path covered by the pressure roller decreases appreciably with increasing number of combing cycles. This causes an undesirable mechanical slippage between the pressure roller and the detaching roller, since the roller path of the detaching roller ARZ does not change at higher numbers of combing cycles, but the roller path of the pressure roller DRZ is reduced by a faster supply of the combed fibre group (see different dashed lines and arrow direction in fig. 3). In other words, the cylinder path of the pressure cylinder is shortened at elevated combing cycles and at a constant cylinder path of the separating cylinder, whereby different cylinder paths dependent on the combing cycles greatly influence the welding process, since the constant pressing force exerted by the pressure cylinder on the separating cylinder is no longer sufficient to rotate at the same or at least approximately the same rotational speed as the separating cylinder. The reason for the reduced rotational speed of the pressure roller, which is dependent on a higher number of combing cycles or a higher rotational speed of the circular comb, can be explained by the fact that a faster supply of the combed-out fiber mass is no longer exerted with the rotational movement of the separating roller with a sufficient counter force in the form of a drag on the pressure roller, so that the rotational speed of the pressure roller can no longer be adapted to the rotational speed of the separating roller at a constant contact pressure of 495N, as a result of which different roller strokes are caused for the pressure roller according to fig. 3.

Fig. 4 shows the percentage tolerance of the roller pairs as a function of the number of combing cycles for the roller stroke at a constant contact force F of machine index 40 and 495N, as shown in fig. 3. The effect of the number of combing cycles on the tolerance between the two cylinders of a cylinder pair (ARZ to DRZ) is particularly clearly shown in this figure. The tolerance increases approximately exponentially from the combing cycle number of more than 580KS/min, which leads to a considerable quality loss during the welding process by means of the roller pair. In principle, a tolerance of up to 3% for a qualitative welding process of the cylinder pair is also acceptable, but this is no longer given at a constant contact pressure of 495N and at combing cycles higher than 580KS/min (as shown in fig. 4 by the dashed boundary line).

Fig. 5 shows schematically how the control unit 50 is in connection with the pressure regulator 54 according to the invention in combination with the separating cylinder unit 18 according to fig. 1 and the circular comb 46 of the combing machine.

The compressed air connection 52 is connected via an electrically controllable pressure valve 56 to the respective piston of the separator drum unit 18 depicted in fig. 1, and the pressure regulator 54 controls the electrically controllable pressure valve 56 via the control unit 50. A system pressure of approximately 6.9bar is applied to the compressed air connection 52 and a pressure of between 0.1bar and 6.9bar can be set in a stepless manner via an electrically controllable pressure valve 56 in conjunction with a pressure regulator 54.

In addition to the pressure regulator 54, a rotational angle sensor 58 is connected to the control unit 50, wherein the rotational angle sensor 58 detects the rotational speed of the circular comb 46. The control unit 50 is designed to monitor the rotational speed of the circular comb 46 via a rotational angle sensor 58 and to set a desired pressure acting on the pressure drum of the separator drum unit 18 via a pressure regulator 54. The control unit 50 also comprises a data memory 60 with data about the combing machine rotational speed in combination with the pressure of the pressure roller for the separation roller unit 18 to ensure, via the pressure regulator 54, that a maximum permissible error of not more than 3% between the rotational speed of the pressure roller and the rotational speed of the separation roller is exceeded.

As described above, the electrically controllable pressure valve 56 can be controlled via the pressure regulator 54 according to the invention in conjunction with the control unit 50 in such a way that the system pressure exerted on the compressed air connection 52 can be set steplessly from 0.1bar to a maximum of 6.9bar, wherein the piston of the pressure roller according to fig. 1 is dimensioned in such a way that a pressure between 210N and 610N is already sufficient for achieving a maximum permissible tolerance of 3%, depending on the rotational speed of the combing machine.

According to the invention, it is thus possible to set a pressure according to the number of combing cycles with the pressure regulator, which pressure allows the rotational speed of the pressure roller to be not excessively varied with respect to the rotational speed of the separation roller, whereby the mechanical slippage illustrated in fig. 2 is significantly prevented. In a positive manner, a high quality of the welding process with the roller pairs can thus be maintained according to the combing cycle number.

Fig. 6 shows the tolerance of the roller pair according to fig. 1 as a function of the rotational speed of the combing machine and under different contact pressures which are applied with the pressure regulator according to the invention as explained in connection with fig. 5. The tolerances of the roller pairs shown illustrate the dependence on the number of combing cycles and on the pressure particularly well. The smaller the pressure, the higher the tolerance at elevated combing work cycles and vice versa.

To illustrate the dependence of the tolerance of the roller pair on the applied pressure of the pressure roller and on the number of combing cycles, see fig. 7. The Y-axis is here represented logarithmically, whereby it is clearly shown that the tolerance of the roller pair decreases at least approximately linearly with respect to the increase in pressure. As can be seen from fig. 7, the tolerance of the cylinder pair is four times higher at elevated pressures and high combing duty cycles in the range of 600KS/min to 700KS/min than at low combing duty cycles between 400KS/min and 550 KS/min. It is also shown in fig. 7 by a horizontal broken line at which pressure the tolerance of the roller pair has a maximum tolerance of 3% at different numbers of combing cycles. This situation is correspondingly illustrated in fig. 8, where the X-axis defines the number of combing cycles of 400KS/min to 650KS/min and the Y-axis has the pressure of the pressure cylinder with the maximum 3% tolerance visible from fig. 7. Clearly and clearly shows the at least approximately linear relationship (deviation R) between the increase in the number of combing cycles and the increase in pressure of the pressure roller²= 0.9999) to obtain a maximum allowable error of 3%.

Fig. 9 shows a further alternative embodiment of a separating drum unit 18B, wherein, in contrast to the embodiment according to fig. 1, the two pistons 34a 'and 34B' each have a different first, smaller diameter 40a and a second, larger diameter 40B, respectively. Due to the different sizes of the diameters 40a and 40b of the first piston 34a 'and the second piston 34 b', different pressures can be transmitted at the same pressure via the first piston 34a 'to the first pressure roller 24a and via the second piston 34 b' to the second pressure roller 24 b. The pressure via the second piston 34b 'is greater than the further pressure via the first piston 34 a'. The pressure regulator according to fig. 5 can also be used with this embodiment of the separation cylinder unit 18B to set the respective pressure according to the number of combing work cycles such that the mechanical slip between the respective pressure cylinder 24a, 24B and the respective separation cylinder 22a, 22B has a maximum tolerance of 3%.

It should be mentioned at this point that a pressure regulator for setting the pressing force of the pressure roller can also be used in the case when the quality of the carded fibrous nonwoven after the welding process with the separating roller unit is not in a predetermined quality range. The quality of the carded fibrous nonwoven is defined on the basis of the web uniformity by means of what is known as the CV value, wherein the accuracy of the output web is continuously monitored by means of a movable calendar disk in combination with a contactless induction/turbine sensor. Such quality monitoring systems are known, for example, under the name of Rita Quality Monitoring (RQM). The Lida quality monitoring (RQM) monitors in-line, in particular, the thickness of the fiber fleece, wherein the thickness is an indicator of whether the setting of the pair of separating rollers for the welding process is satisfactory. Accordingly, the sensor for monitoring the rough spot can transmit a data signal to the control unit via a signal line if the quality of the fibrous nonwoven is insufficient, wherein the control unit accordingly controls the pressure regulator in such a way that the pressure roller of the roller pair obtains a sufficient contact pressure for obtaining again an optimum quality of the fibrous nonwoven. Accordingly, the RQM in combination with the pressure regulator is a particularly good quality monitoring system for carded fibrous nonwovens.

It should be mentioned at this point that the pressure regulator can be set as a function of the number of combing cycles and/or as a function of the quality of the carded fibrous nonwoven, wherein the quality of the carded fibrous nonwoven with respect to strength is emphasized by the minimization of the welding process and the thick spots in order to ensure an optimum quality of the yarn in the final spinning process.

List of reference numerals

10	Combing head
		12	Pliers
14	Upper nipper
		16	Lower nipper
18、18B	Separation roller unit
		20a、20b	Roller pair
22a、22b	Separating drum
		24a、24b	Pressure roller
26a、26b	Pressing device
		28a、28b	Bearing support
30a、30b	Bearing assembly
		32	Block
34a、34b	Piston
		36a、36b	Piston rod
38a、38b	Comb
		40a、40a‘、40b‘	Diameter of
42	Control device
		44	First driving motor
46	Round comb
		48	Second driving motor
50	Control unit
		52	Compressed air interface
54	Pressure regulator
		56	Pressure valve
58	Rotation angle sensor
		60	Data storage

Claims

1. A detaching cylinder unit having a device for pressure cylinders of a detaching cylinder pair of a combing machine, the detaching cylinder unit having: at least one first roller pair (20 a, 20 b) consisting of a first separating roller (22 a) and a first pressure roller (24 a) which can be rotated in the combing machine with a reciprocating step movement; at least one first pressing device (26 a) for pressing the first pressure roller (24 a) and the first separating roller (22 a) of the first roller pair (20 a) against one another, wherein the first pressure roller (24 a) is pressurized via the first pressing device (26 a) and the first pressing device (26 a) is connected to a compressed air connection (52), characterized in that the compressed air connection (52) is connected to a pressure regulator (54) which is designed such that a corresponding pressure for the first pressure roller (24 a) for pressing against the first separating roller (22 a) can be set as a function of a predefined rotational speed of the combing machine.

2. The separator roller unit according to claim 1, wherein the pressure regulator (54) comprises at least one electrically controllable pressure valve (56).

3. The separator roller unit according to claim 1 or 2, characterized in that the pressure regulator (54) sets a respective pressure between about 210N and about 640N depending on the rotational speed of the combing machine.

4. The detaching cylinder unit according to any one of claims 1 to 3, characterized in that the predefined rotational speed of the combing machine is at least approximately linearly dependent on the settable pressure for the first pressure cylinder (24 a).

5. The detaching cylinder unit according to one of claims 1 to 4, characterized in that the predefined rotational speed of the combing machine is between 400KS/min and 700 KS/min.

6. The detaching cylinder unit according to any one of claims 1 to 5, characterized in that a slip between the first pressure cylinder (24 a) and the first detaching cylinder (22 a) with a maximum tolerance of 3.0% can be set according to the predefined rotational speed of the combing machine in combination with the respective pressure.

7. The detaching cylinder unit according to claim 6, characterized in that a control unit (50) is connected to the pressure regulator (54) and has a data memory (60), in which a data set of a 3% tolerance error for the slippage between the predefined rotational speed of the combing machine and the respective pressure is saved, so that the control unit (50) sets the correct pressure for the first pressure cylinder (24 a) via the pressure regulator (54) in correspondence with the set rotational speed of the combing machine.

8. The detaching cylinder unit according to claim 7, characterized in that a rotational angle sensor (58) is provided, which monitors the rotational speed of the combing machine and transmits it to the control unit (50) for setting the correct pressure for the first pressure cylinder (24 a) via the pressure regulator (54) according to a predefined rotational speed of the combing machine.

9. The separation drum unit according to any one of claims 1 to 8, characterized in that the pressing device (26) has a first piston (34 a) which can be loaded with a pressure medium, preferably air, for the first pressure drum (24 a), wherein the first piston (34 a) is connected with the compressed air interface (52) via the pressure regulator (54).

10. The separator drum unit according to claim 9, wherein the first piston (34 a) has a diameter (40) configured such that a pressure for the first pressure drum (24 a) of between about 210N and about 640N can be set via the pressure regulator (54).

11. The separator roller unit according to claim 10, wherein the first piston (34 a) has a diameter (40) of between about 30mm to about 38mm, preferably about 32 mm.

12. The detaching cylinder unit according to one of claims 1 to 11, characterized in that a second cylinder pair (20 b) consisting of a second detaching cylinder (22 b) which can be rotated in a reciprocating step movement in the combing machine and a second pressure cylinder (24 b) is provided, wherein the second cylinder pair (20 b) is connected downstream of the first cylinder pair (20 a) in the transport direction of the fibrous fleece.

13. The detaching cylinder unit according to claim 12, characterized in that the respective pressing device (26 a, 26 b) is configured to load a first pressure roller (24 a) of the first roller pair (20 a) and a second pressure roller (24 b) of the second roller pair (20 b) via the pressure regulator (54), wherein the second pressure is greater than the first pressure depending on the rotational speed of the combing machine.

14. Combing machine having a separating roller unit (18) according to one of claims 1 to 13.