Comber Having an Electromotively Driven Feed Cylinder

The invention relates to a feed cylinder for a nipper assembly of a comber, said feed cylinder being connected to an electromotive drive via a gear stage.

The invention further relates to a method for setting the noil extraction level on a comber for forming a combed fibrous web with a feed cylinder designed in accordance with the invention.

The invention further relates to a comber comprising at least one feed cylinder which is designed in accordance with the invention.

A drive device for the feed cylinder of a comber is already known from the published document EP-360 064 A1, wherein an electric motor is installed in the region of a nipper assembly, said electric motor being connected to the feed cylinder via an intermediate gearbox. In this case, the drive pulses of the electric motor are synchronized with the movement of the nipper assembly. In this connection, e.g. the respective rotation angle of a circular comb shaft is tapped via an incremental sensor and is used as the basis for controlling the drive of the feed cylinder.

The use of a special electric motor for the respective feed cylinder of a comber makes it possible to adjust the feed rate and the feed intervals of the feed cylinder in an individualized manner even during ongoing operation. As of the filing date of the application for EP'064, electric motors of the type that would be options for this use were still relatively large and heavy, and therefore additional energy expenditure was required for the mass of the electric motor and the gear unit that also had to be moved during the back and forth movement of the nipper assembly. In addition, the bearing points of the pivot levers for the nipper assembly were additionally loaded and the susceptibility to wear was increased.

In another published document DE-195 06 351, it was proposed to drive the feed roller from a pivot bearing of the nipper shaft such that the electric motor that is used no longer needs to be moved with the nipper assembly. In this connection, an electric motor fastened on the machine frame drives a pulley, for example, which is mounted on the pivot bearing, via which said pulley the drive is transferred via a toothed belt to a pulley, which is connected to the feed cylinder in a rotationally locked manner. This embodiment ensures that the mass or the weight of the electric motor no longer needs to be moved along during the nip. The disadvantage of this embodiment, however, is that relatively long gear elements (e.g., toothed belts) must be used in order to transfer the drive from the electric motor to the respective feed cylinder. In general, it is problematic to install gear elements for transferring drive in the region between the electric motor and the feed cylinder, since said gear elements can become contaminated relatively quickly due to fiber fly. In order to prevent this, these gear elements must be provided with corresponding casings. This, on the one hand, is complicated and expensive and requires additional space. In addition, at least a portion of the weight of the casings must be moved along once more during the nip.

It is therefore an object of the invention to propose a solution such that the feed cylinder can be driven individually via an electric motor and such that the disadvantages of known solutions are avoided.

This object is achieved by proposing that the electromotive drive and the gear stage for the drive of the feed cylinder are installed inside the feed cylinder, which is designed as a hollow body.

The electromotive drive (or the electric motor) as well as the gear elements are therefore located in a sealed space inside the hollow body of the feed cylinder and, therefore, are protected against contamination. In addition, the mass of the electric motor integrated in the feed cylinder is relatively small, and therefore large additional loads (energy, bearing loads) do not occur when the motor is moved along during the nip. Integrating the electromotive drive into the cavity of the feed cylinder results in a compact modular unit, which is not susceptible to contamination and is easy to install and remove.

Moreover, it is proposed that the feed cylinder is rotatably mounted via bearing elements installed on bearing sleeves, which protrude at the ends of the feed cylinder into the cavity thereof.

Advantageously, the electromotive drive and the gear stage are disposed between the bearing sleeves, which protrude into the feed cylinder, wherein the gear stage is connected, on one side, to the motor shaft of the electromotive drive in a rotationally locked manner and, on the other side, is connected to the hollow body of the feed cylinder in a rotationally locked manner.

Moreover, it is proposed that the electromotive drive comprises a control part and is equipped with a sensor unit for detecting the angular position of the motor shaft. The control part is likewise located inside the cavity of the feed cylinder.

Due to the use of bearing sleeves to support the hollow cylinder, it is possible that the the supply leads to the electromotive drive can be fed through the cavity of one of the bearing sleeves.

In order to install the feed cylinder on the nipper assembly, it is proposed that the end of the bearing sleeves protruding from the hollow body of the feed cylinder is fastened on the nipper assembly.

It is proposed that the electromotive drive comprises a servomotor in order to permit the feeding process to be controlled in a positionally accurate manner.

Moreover, a method is proposed for setting the noil extraction level on a comber comprising a feed cylinder of a nipper assembly, said feed cylinder being driven by an electromotive drive, in order to form a combed fibrous web.

In this connection, it is proposed that the ratio of the lengths of the fiber mass protruding from the clamping point of the nipper assembly for the combing process and for the detaching process is determined by means of a controlled movement of the feed cylinder with regard to the rotation angle and the rotation direction.

The ratio of the lengths is determined by: Length of the fiber tuft for the combing process/Length of the fiber tuft for the detaching process.

In known combers, the ecartement (smallest spacing between the lower nipper plate and the clamping point of the downstream detaching roller) is adjusted in order to determine the noil extraction level (percentage portion of the noil). This takes place at an adjusting device in the region of the nipper shaft and can be carried out only when the machine is at a standstill. This setting process is time-consuming and is limited to certain stages. By means of the proposed activation of the electromotive drive, the noil extraction level can be set in a flexible manner, even during ongoing operation, merely by means of the control. It is therefore possible, e.g. by reversing the rotation direction of the feed cylinder, to move a previously fed amount of feed for the detaching process back by a partial amount in order to shorten the length of the fiber material (also referred to as the fiber tuft) protruding from the nipper clamping point for the combing process. The noil extraction level can therefore be reduced without changing the ecartement. In contrast thereto, it is also possible to control the drive of the feed cylinder such that the noil extraction is increased while the ecartement remains the same. In this case, an additional partial amount is fed to the amount of feed of the fiber material shortly before the nipper is closed for the combing process. As a result, a longer fiber tuft is available for the combing process. After completion of the combing process and with the nipper re-opened, the additionally fed partial amount is retracted once more by reversing the rotation direction of the feed cylinder in order restore the original length of the fiber tuft, without the additional partial amount, for the subsequent detaching process.

Moreover, a method is proposed for forming a fibrous web on a comber using the feed cylinder that is claimed according to the invention, wherein, in each case before the clamping point of the nipping unit is closed, the previously fed amount of feed is moved back by a predetermined partial amount such that, when the nipping unit (in short: “nipper”) is dosed, the free end (also referred to as the “fiber tuft”) of the fiber material presented to a comb segment has a length that has been shortened by this partial amount. This partial amount can be determined exactly via the reversing movement of the feed cylinder. By reducing the length of the fiber tuft before extraction, the combed portion (non) can be reduced.

A spinning mill owner is anxious to obtain the highest possible productivity in combination with a required level of quality. That is, the objective is to minimize the waste (nod) on the comber while continuing to obtain the quality of the comber sliver produced on the comber that is desired by the customer.

By means of the corresponding activation of the electromotive drive of the feed cylinder, the retracted partial amount of the amount of feed can continue to be varied, during the machine setup process, until a result is obtained that is optimal for the spinning mill operator.

By means of a corresponding activation of the electromotive drive of the feed cylinder, the length of the fiber tuft to be combed can be varied while the ecartement remains the same, also in the case of feeding in reverse (supplying the amount of feed when the nipper moves in reverse) or in the case of mixed feeding (feeding in forward and reverse movements).

The essential point is that the length of the fiber tuft presented for the combing process is varied by means of a controlled rotational movement (rotation forward and in reverse) of the feed cylinder.

In order to also comb the rear end of the fiber tuft during the detaching process, the clothing of a top comb is engaged into the fiber tuft. That is, the fiber material that is pulled out of the presented fiber tuft by means of the detaching device (e.g., a detaching roller pair) is drawn through the clothing of the top comb at least with the rear end of said fiber material. As a result, in particular, “neps” and other impurities that are still located in this region are retained and discarded.

The feed cylinder designed in accordance with the invention is preferably used in a comber.

In order to ensure synchronization between the electromotive drive of the respective feed cylinder and the remaining units participating in the combing process (e.g., nipper, circular comb, detaching rollers), it is proposed that a control part of the electromotive drive of the at least one feed cylinder is connected to a central control unit, which is connected to a sensor unit, via which the rotation angle of at least one main shaft of the comber is determined.

For the purpose of flexibly adjusting the drive of the feed cylinder, it is proposed that the comber is provided with a central input point, via which the size of the amount of feed, the size of the partial amount of the amount of feed to be moved back, and the time interval of the amount of feed and the partial amount of the amount of feed can be set.

Further advantages of the invention are illustrated and described in greater detail with reference to the following exemplary embodiments, in which:

FIG. 1 shows a schematic side view of a combing head of a comber, in a detaching position,

FIG. 2 shows a schematic side view according to FIG. 1, in a combing position,

FIG. 3 shows a sectional illustration of a feed cylinder designed in accordance with the invention,

FIG. 4 shows a diagram for depicting a possible feed interval.

FIG. 1 shows a schematic side view of a combing head 1 of a comber, in which a plurality of such combing heads is typically disposed so as to lie next to one another.

The combing head comprises a nipper assembly 2 (in short; “nipper”), which swings back and forth and is pivotably mounted on a machine frame of the comber via the pivoting arms S1, S2.

The pivoting arm S1 (there can also be two) is moved back and forth via a nipper shaft ZW, as indicated by a double arrow. Said pivoting arm is pivotably fastened on a nipper frame 3 of the nipper via a pivot axis 22. In a front region of the nipper 2, one (or two) pivoting arm S2 is connected to the nipper frame 3 via a pivot axis 23, wherein the other end thereof is supported on a shaft 9 of a circular comb 8, said shaft being rotatably mounted in the machine frame. For the combing process, the circular comb is provided on its outer circumference with a comb segment 10.

The nipper 2 comprises a lower nipper plate 4, which is fixedly installed on the nipper frame 3. An upper nipper plate 5 (also referred to as a “nipper knife”) is installed above the lower nipper plate 4 so as to be pivotable via a pivot axis 6 and via pivoting arms B1, B2, as indicated by a double arrow. In the example shown in FIG. 1, the nipper 2 is in an open and foremost position.

In this position, the front end of the lower nipper plate 4—where a damping point KS is also located—has a spacing E (ecartement) from a damping line KL of a downstream detaching roller pair 20. As known, a further roller pair, which is not characterized in greater detail, can be disposed downstream of the detaching roller pair in order to support the joining process. An end VE of a previously formed fibrous web V protrudes from the damping line KL, wherein said end is overlapped with the end FB (referred to as the fiber tuft) of a fiber material W that protrudes from the nipper 2. Due to the rotation direction of the detaching rollers 20, which is illustrated by arrows, the end of the fiber tuft FB enters the damping line KL of the detaching roller pair 20, whereby the fibers that are captured are pulled out of the fiber tuft FB and are joined with the fibrous web V. This process is generally known and, therefore, will not be described in greater detail. During the detaching process, the rear ends of the pulled-out fibers, at the least, are drawn through a clothing of a top comb, which is not shown and which is located between the front end of the lower nipper plate 4 and the detaching roller pair 20. The use of such a top comb is also generally known.

A rotatably mounted feed cylinder 12 is installed in the nipper 2, above the lower nipper plate 4, for the purpose of feeding the fiber material W (e.g., a wadding from a lap or slivers from a can) to the damping point KS of the nipper 2 during a nip in a stepwise manner with a predetermined amount of feed. The amount of feed is fed intermittently within a certain time interval during a nip. Modern combers can carry out up to 600 nips per minute. In the present example, the intermittent drive of the feed cylinder 12 is carried out by an electromotive drive M (in short: “motor), which is installed inside the feed cylinder designed as a hollow cylinder, as is apparent from FIG. 3, which will be discussed in greater detail below.

FIG. 2 shows the nipper 2 in a rear position, in which it is dosed, In this connection, the nipper knife 5 (upper nipper plate) is pressed against the lower nipper plate 4 with pressure in the region of the damping point KS under the effect of at least one schematically indicated spring arm FD, thereby damping the fiber material W in this region.

By means of the rotational movement of the circular comb 8, which is indicated by an arrow, the clothing of the comb segment 10 plunges into the end (fiber tuft FB) of the fiber material W protruding from the damping point KS and extracts the fibers and other impurities that are not fixedly held via the damping point. These extracted components are then transported downward via known disposal devices.

In order to enable the movement of the feed cylinder 12 to be coordinated exactly with the movement of the circular comb shaft 9, the respective rotation angle of the circular comb shaft 9 is sensed via a sensor 19 and is transmitted to a control unit ST via a line 19. The control unit ST is connected via the line 25 to a control part S, which is likewise disposed inside the hollow cylinder H of the feed cylinder (FIG. 3), and which is used to control the motor M inside the feed cylinder 12. A rotary encoder is integrated (not shown) in the control part S, via which the respective rotation angle of the motor shaft M1 of the motor M is detected.

In order to supply power to the motor M, the motor is connected to a schematically illustrated current source 30 via a control part S and the line 26.

As indicated by a dashed arrow inside the feed cylinder 12, the amount of feed that was previously fed via the feed cylinder in the forward movement of the nipper (when the nipper moves toward the detaching rollers) was then moved back by a partial amount a, shortly before the nipper 2 dosed. Therefore, the fiber tuft FB protruding from the damping point has a length L1, which is shortened by this partial amount a. That is, a shorter fiber tuft FB (having the length L1) is available for the combing process (FIG. 2) than for the downstream detaching process (having the length L). This is due to the fact that, after completion of the combing process and after initiation of the forward movement of the nipper and with the nipper re-opened, this partial amount a, which was moved back, is fed once more, along with an amount of feed b, through the feed cylinder. This is explained in greater detail below by means of a diagram (FIG. 4).

FIG. 3 schematically shows a cross section of the feed cylinder 12 proposed according to the invention, said feed cylinder comprising a hollow cylinder H, in which an electromotive drive having a motor M, a gear G, and a control part S is installed. Another rotary encoder is connected to the control part 5, wherein said rotation-angle sensor is not shown in greater detail and via which the respective rotation-angle position of the motor shaft is tapped and transmitted to the control part S.

The electromotive drive is located in the cavity HR of the hollow cylinder H between two bearing sleeves 32, 33, on which the hollow cylinder H is rotatably mounted via bearings N. The bearing sleeves 32, 33 are held by bearing elements 14, 15, which are fastened on the nipper frame 3. The bearing sleeves 32, 33 are fastened in the bearing elements 14, 15 via schematically indicated screws R. The bearing elements 14, 15 can also be designed in two parts (not shown) in order to simplify the assembly of the bearing sleeves 32, 33. The bearing sleeves 32, 33 have a central through-opening D for providing access for fastening the electromotive drive inside the cavity H and for introducing lines (power cable, control lines).

The motor M, which forms a unit together with a control part 5, is fixedly connected to the bearing sleeve 14 via fastening means, which are not illustrated. The output shaft M1 of the motor M protrudes into a gear G, in which a rotational speed reduction takes place. The reduced rotational speed is transferred at the output shaft M2 of the gear G to the inner surface of the hollow cylinder H of the feed roller 12. The closed-loop control of the motor rotational speed and the angular movement of the shaft W2 take place via the control part 5, which, in turn, is connected to a central control unit ST via the line 25, which is routed through the bearing sleeve 32. Power is supplied by means of a current source 30 via the line 26 through the bearing sleeve 32.

A coupling 34 is non-rotatably fastened on the shaft M2 via a fastening means, e.g., via a screw 40, for the purpose of transferring the rotational movement of the shaft M2 of the gear G with the hollow body H of the feed cylinder 12. A threaded bore 41 is formed at that end of the coupling (as viewed in the axial direction relative to the rotational axis 11 of the feed cylinder) that is opposite the end in which the receiving bore 37 for the shaft M2 is located. A screw 38, which protrudes through a bore B of a disk 36, is screwed into the threaded bore. A slotted clamping ring 35 is located between the coupling 34 and the disk 36; in the clamped state, the outer circumference U of said slotted clamping ring rests against the inner surface H1 of the hollow body.

The clamping ring 35 is provided on both end faces thereof with slanted clamping surfaces K, against which slanted surfaces rest, each of which are formed on an end face of the coupling 34 and the disk 36 rest.

The disk 36 is clamped against the coupling 34 via a screw 38, which can be tightened through the central opening of the bearing sleeve 33. In so doing, the outer diameter of the slotted clamping ring 35 is enlarged via the clamping surfaces K, whereby the outer circumference U of the clamping ring comes to rest against the inner circumference H1 of the hollow profile and forms a fixed clamped connection.

The control unit ST is connected to an input unit 44 (e.g., a keyboard) and an optical display 45 (e.g., a monitor) via the line 47 in order to permit said control unit to be programmed with desired amounts of feed and feed intervals (depending on the material, no extraction, staple length, etc.) for activating the motor M of the feed cylinder 12 via the control part S. It is therefore possible to specify corresponding values depending on the corresponding material feed and the desired no extraction in order to control the rotational movement of the feed cylinder accordingly via the motor M. In order to ensure a synchronized movement during a nip of the feed cylinder 12 with, e.g., the circular comb shaft 9, the rotation angle of the circular comb shaft 9 is determined exactly via a sensor 18, which transmits its signals to the control unit ST via the line 19. In the control unit ST, the values entered via the keyboard 44 are adjusted according to the rotation-angle position of the circular comb shaft via an available program (software), and the control part S of the motor M is controlled accordingly. As described above, rotation-angle detection, which is not illustrated, is also provided for the shaft M1 of the motor M and can be integrated, e.g. in the control part S.

The method of a “forward feed” claimed according to the invention is illustrated and described in greater detail in the diagram in FIG. 4. In this connection, the movements and time intervals of the nipper, the nipper knife (upper nipper plate) of the feed cylinder (feed) and the combing period (combing) of the comb segment of the circular comb during a nip were illustrated. One nip is subdivided into 40 indices. In the index 0/40 position, the nipper is located in a rearmost position, in which the spacing A between the nipper and the downstream detaching roller 20 is greatest. This position is also referred to as rear dead center HT. The smallest spacing E (also referred to as “ecartement”) between the nipper and the detaching rollers exists at index 24, in which the nipper starts to move back in the reverse direction. This position is referred to as front dead center VT.

Between index 34 to index 10, the nipper knife is located in a clamped position with the lower nipper knife, and therefore the nipper is closed in this time period. As is apparent in the lower part of the diagram, the noil extraction process (combing) by the comb segment 10 of the circular comb 9 also takes place during this period. As is evident from the diagram, the nipper is open furthest at front dead center VT. The closing movement of the nipper then takes place during its movement in reverse, between index 24 and index 34.

The feeding of an amount of feed b for the combing process takes place by means of a forward rotation (FIG. 1) of the feed cylinder, or by a corresponding activation of the motor M via the control part S. This feeding process starts at index 14 and ends at index 24, at which the furthermost position of the nipper has been reached. The detaching process by the detaching rollers takes place even before the foremost position of the nipper is reached. This is generally known (see, e.g. “Die Kurzstapelspinnerei”; volume 3; The Textile Institute; page 31; ISBN 3-908.059-01-1), which will not be discussed in greater detail here. The depiction of the engagement of a top comb before the detaching process is also omitted here.

As is evident from the diagram in FIG. 4, the previously fed amount of feed b is moved back again by the partial amount a during the movement of the nipper in reverse, between index 24 and index 34. This takes place by means of a corresponding activation of the motor M of the feed cylinder via the control unit ST, or via the control part S, whereby the motor M is rotated in reverse, as is indicated schematically, for example, by means of the dashed arrow in FIG. 2. This retraction must always be completed before the nipper is closed completely, at index 34. That is, a fiber tuft FB having the length L1 is available for the extraction process between index 34 and index 6, wherein said fiber tuft is reduced by the partial amount a relative to the length L, which is present in the detaching process at front dead center VT (L1=L−a).

Once the combing process has been completed (index 6), the partial amount a that was previously moved back is fed once more. This feeding of the partial amount a takes place before the feeding of the actual amount of feed b. The feeding of the partial amount a can even take place before the index 10, i.e. even in the closed nipper.

The movement of the feed cylinder can be carried out exactly and rapidly by means of the proposed use of an electromotive drive inside the feed cylinder, wherein the noil extraction level can be easily varied and set. AH that is required is a manual entry at the input device 44 in order to vary and set the mail extraction level accordingly.

That is, the extraction level (noil) can be varied by selecting the length of the retracted partial amount a without the need to adjust the ecartement E. The mass of the electromotive drive integrated inside the feed cylinder 12 is relatively small, and therefore the additional amount of energy required during the pivoting of the nipper is relatively small.

The proposed drive and control device for the feed cylinder also permits corresponding adaptations to be made when a feed in reverse or a mixed feed (combined feeding in forward and reverse) is provided. That is, activating the electromotive drive for the feed cylinder makes it possible for the length of the fiber tuft (FB) in the detaching process (in VT) to be different than the length of the fiber tuft FB in the combing process (in HT) without the need to adjust the ecartement (spacing E).

Comber Having an Electromotively Driven Feed Cylinder

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