EP1587973B1 - Fiber conveying and discarding device to be connected to a carder - Google Patents

Description

The invention relates to a fiber transport and -ablegevorrichtung according to the preamble of patent claim 1

From patent CH 692 349 a device is known, in which the sliver leaving the card first passes into a drafting system and from there into the can stock, which deposits the sliver in the form of loops in the pot. The drafting system is designed as Regulierstreckwerk and arranged directly on the top of the can stock. In this way, which is found to be particularly advantageous in the patent CH 692 349, the distance between the output of Regulierstreckwerks and the band inlet opening of the can can be kept very low.

Control technology, the device according to the Swiss patent is very demanding. The fundamental problem is that the speed of the card on the one hand, drafting on the other hand and finally the can stock must be suitably coordinated with each other. Speed differences must be compensated or regulated. For this purpose, according to the Swiss patent, the way is taken to include in the loop both the Regulierstreckwerk, as well as the drive motor of the card. This assumes that the individual components are linked to each other in terms of control technology. In practice, however, there is often the problem of additionally or subsequently growing a can can with an intermediate drafting device on an existing carding machine. In such cases, it is often not possible or associated with too much technical effort to intervene in the sense of overall control of the system in the speed control of the card.

US 5,774,940 discloses a device in which, for a given carding speed, a regulation of both the roller pairs of the drafting system takes place, as well as a separate control of Kannenstockantriebs. Between the Regulierstreckwerk and the Kannenstock the sliver is guided as a freely sagging loop. A level sensor detects the height of this loop, from this signal is derived via a process computer, a speed adjustment for one hand Regulierstreckwerk and on the other hand, the depositing speed of the can can.

In practice, it has been found that in modern cards, which work with high belt speeds and entertaining control of Regulierstreckwerkes when regulating the depositing speed of Kannenstockes by means of z. As a very fast-working servo drive, the mechanics of the can-head is overwhelmed, the entertaining control of Regulierstreckwerkes sufficiently fast to follow. The reason for this lies in the relatively large moving masses of the can cane, which in the case of a short-term speed adjustment lead to high mechanical forces, in particular to the bearing of the rotating head of the can-can.

From GB1 436 029 A a device is known in which the fiber is deflected to compensate for the sliver length. Serves for this purpose a tube having two sections, which is rotatably mounted about the axis of the first, horizontal portion, wherein the second portion is angled relative to the first. When leaving this second section, the sliver is deflected in the form of a loop, and then passes over another bend to the can-stock. If the tape is lightly loaded, the tube assumes its lowered position. When shortening the fiber passing through the tube, the angled portion of the tube is raised in accordance with the fiber shortening, the resulting angle of rotation of the first tube portion is detected, and the fiber speed is adjusted. The tension exerted by the tube on the fiber depends on the angle of rotation of the tube. However, this tension can have an influence on the strip quality of the fiber.

The invention has for its object to provide a working with simple control means fiber transport and -ablegevorrichtung for connection to a card, which allows the adjustment and the compensation of the belt speed without affecting the tape quality behind the drafting system output.

The solution to this problem is in a generic fiber transport and -ablegevorrichtung characterized by at the free end of a pivotable about a pivot axis and to maintain a certain belt tension a back pressure on the sliver-performing arm arranged deflecting means over which the sliver is guided in a deflection.

By means of simple control technology, such a fiber transport and depositing device makes it possible to adapt and equalize the belt speeds behind the fine-regulating drafting system. According to the invention, the control is based on a local displacement of deflecting means for the sliver, wherein these deflecting means. consist of an arm pivotable about a pivot axis, at the free end of a roller can be freely rotatably supported, over which the sliver is guided and deflected. Therefore, the sliver does not run directly from the last pair of rollers of the drafting to the can stock, but it takes the "detour" on the displaceable deflection. On the one hand, this leads to the automatic maintenance of a certain belt tension and thus to the maintenance of the belt quality leaving the drafting system. On the other hand results in a detection option due to the local displacement of the deflection. For this purpose, discrete signal transmitters are provided for a first and for a second end position of the deflection means. It is therefore not the size of the local displacement of the deflection over the entire possible range of motion, but only discrete end positions or an approximation to such end positions are detected.

Finally, according to the invention means are provided for changing the drive speed of the can stack in the case of a signal output by one of the signal transmitters and in dependence on the time interval which has elapsed since the last signal output. Only when one of the end positions is reached, is an adaptation of the basic ratio by intervention in the operating speed of the can-can stock. The longer the time span between the successive reaching of two end positions, the lower the speed adjustment of the can cane.

An intervention in the often completely independent control of the card is not required, which is why the fiber sliver transport and -ablegevorrichtung invention also suitable for retrofitting and for retrofitting to an existing card. Since only two end positions and not z. B. all intermediate values are detected, the control engineering effort is low despite the achievable high belt speeds.

Of advantage is finally the smooth running of the sliver by this is performed on the arranged at the free end of the arm deflection, which can no longer affect the quality of the sliver, as this leaves the drafting. Especially at the high desired tape speeds, such a tape guide is characterized by a quieter transport of the sliver, as z. B. in the case of a freely sagging loop, as described in connection with a continuously operating level sensor in US 5,774,940. An additional disadvantage of a sagging sliver loop-detecting level sensor is that the undefined sagging of the sliver loop can just lead to such Fehlverletzungen in the sliver, which were previously eliminated consuming by the Regulierstreckwerk.

With a preferred embodiment of the fiber transport and -ablegevorrichtung it is proposed that for the detection of the two end positions each two signal transmitters are arranged slightly offset from one another. In this way, an approach to the end position can already be detected by signal technology, and accordingly the control can be refined. Proximity switches are preferably used as signal transmitters.

For the pivoting arm a particularly lightweight and thus almost inertia-free construction is proposed, in which the arm consists of a thin-walled tube. Particularly suitable for this purpose is a tube made of carbon fiber, which combines the advantage of low weight with high strength and extensive freedom from vibration. Such an arm works with very low moments of inertia and therefore a good response to any elongation or reduction of the deflected over the arm Faserbahdes.

To improve the response of the deflection on each change in length of the sliver further contributes to a stationary on the pivot axis for the arm further role, which serves as a further deflection in this case. Preferably, in this case, the pivot axis is arranged for the arm on the can stock, and the sliver is guided vertically between the other role and the can stock, so that the sliver passes on the shortest path and from above vertically down into the can stock.

In order to achieve an exact response of the deflection, it is advantageous if they are displaceable only against a certain counterforce, for which purpose preferably a damping mechanism is used. Accordingly, an embodiment of the invention is characterized in that the deflection means with a in the direction of displacement acting damping element are provided with progressive damping characteristic, so that unfavorable vibrations are largely avoided for the regulation of Kannenstocks. Preferably, the damping element is arranged in such a way that this acts damping on the pivot axis of the pivotable arm.

Fig. 1

in einer Seitenansicht ein an eine Karde angebautes Streckwerk sowie einen diesem Streckwerk nachgeschalteten Kannenstock, welcher hier zur Aufnahme von insgesamt drei Faserbandkannen vorbereitet ist;

Fig. 2

die Gegenstände nach Fig. 1 in einer Draufsicht;

Fig. 3

in einer Schnittdarstellung einen auf dem Kannenstock angeordneten Arm, über den das Faserband auf dem Weg vom Streckwerk zum Kannenstock umgelenkt wird;

Fig. 4

den Arm nach Fig. 3 in einer gegenüber Fig. 3 um 90° verdrehten Ansicht;

Fig. 5

eine vergrößert dargestellte Einzelheit der Fig. 3 und

Fig. 6

einen Schnitt in der in Fig. 5 eingezeichneten Ebene VI-VI durch die Lagerung des verschwenkbaren Arms.

Further details of the invention will be explained below with reference to an embodiment and with reference to the drawings. Show:

Fig. 1

in a side view of a drafting device attached to a carding machine and a can stock connected downstream of this drafting system, which here is prepared for receiving a total of three sliver cans;

Fig. 2

the objects of Figure 1 in a plan view.

Fig. 3

in a sectional view of an arranged on the cans arm, over which the sliver is deflected on the way from the drafting to Kannenstock;

Fig. 4

the arm of Figure 3 in a relation to Figure 3 rotated by 90 ° view ..;

Fig. 5

an enlarged detail shown in FIG. 3 and

Fig. 6

a section in the drawn in Fig. 5 plane VI-VI by the mounting of the pivotable arm.

The Fign. 1 and 2 show an overall illustration of a carding machine 1, which is shown only partially here, and which is followed by a drafting unit 2 in relation to the strip running direction, to which in turn a can can 3 is connected downstream. In the can stock 3, a pot is turned off in a conventional manner, in which the sliver is stored in controlled loops. In the present case, the can stock 3 is provided with a can changer, which offers space for a total of three sliver cans 4. The sliver is provided with the reference numeral 5.

In the drafting system 2, a controlled stretching of the sliver coming from the carding 1 takes place, so as to improve the structure and in particular the uniformity of the sliver. Such drafting systems are known, for. B. from the Swiss patent CH 692 349. A drafting system often consists of several pairs of rollers, wherein at least the last pair of rollers with a higher, individually adjustable speed is driven. This speed difference causes the stretching and equalization of the sliver.

The drafting system 2 is therefore designed as Regulierstreckwerk and this has a main drive and a separate, fast-reacting regulating drive. The main drive has a fixed, but in size programmable translation to the card 1. The Regulierantrieb has a fixed, but in its size but also programmable basic translation for driving the can stack 3.

To achieve the desired structure of the sliver, the last pair of rollers or possibly the last pairs of rollers of the drafting system 2, which are often referred to as drafting system exit rollers, can accelerate or retard in the short term by the fast-reacting Regulierantrieb compared to the basic translation. By means of a fast-acting servo drive z. B. can be the output rollers with a frequency in the millisecond range up to 25% change in their speed. Such a rapid change in speed can not follow the drafting unit 2 downstream can Stock 3, since its mechanical drive components react too slow. As a result, there are almost permanent differences in speed.

Due to this different dynamics of Regulierstreckwerks one hand, and the Kannenstocks on the other hand, there are also changes in the effective band length of the sliver on the way from the drafting 2 to Kannenstock 3. These changes in length are compensated short term, that the sliver 5 on its way from the drafting 2 to Kannenstock 3 is guided over the free end of a pivotable about a pivot axis 6 arm 7. As a result of its pivoting about the pivot axis 6 of the arm 7 and a freely rotatably mounted at its free end roller 8 forms a correspondingly effective sliver length displaceable deflection means for the sliver. By a defined counterforce, which is preferably generated by a counterweight, the arm 7 is kept under constant counter pressure, so that the sliver 5 remains evenly stretched on its way from the drafting to the can cane. This tension is so low that the structure of the sliver, as this leaves the drafting system 2, is no longer affected.

Based on the Fign. 3 to 6, details of the deflecting means composed primarily of the arm 7 and the roller 8 mounted thereon are explained below.

On the top of the can stock a short stand 11 is fixed, which carries at its upper end the bearing for the pivot axis 6 of the arm 7. The arm 7 is therefore pivotable about the axis 6, wherein damping elements 16 in the region of the pivot axis 6 exert a progressive damping effect on the rotational movement of the arm, d. H. the greater the speed of rotation of the arm 7, the greater the damping. The long lever of the arm 7 consists of a tube 9, at the free end of which the already described roller 8 is freely rotatably mounted. The tube 9 is made of a very light, but low-vibration and high-strength material such. B. carbon fiber.

The short lever of the arm 7 is formed by the weight member 10. The weight element 10 sits as close as possible to the pivot axis 6 of the arm so as to bring the mass inertia forces close to the pivot center. The weight element 10 is screwed via an adjusting thread 12 with lock nut 13 in the arm 7, wherein by adjusting this thread, the leverage of the weight element can be adjusted.

The counterweight for the long arm 7 and the roller 8 serving weight element 10 is so dimensioned and balanced that the arranged at the free end of the tube 9 roller 8 always exerts a certain tension on the guided over this roller 8 sliver 5. It is advantageous if the sliver 5, as shown in FIG. 3 reveals, is guided in the middle position of the arm 7 in a deflection angle of about 90 ° on the roller 8.

Fig. 4 reveals in another view that the deflection means for the sliver except the displaceable roller 8 still another role 14 belongs. The further roller 14 is freely rotatably mounted on the pivot axis 6 of the arm 7. Furthermore, the roller 14 is arranged so that the fiber sliver guided over it 5 then passes vertically into the arranged below Kannenstock 3.

According to FIGS. 5 and 6, the pivoting movement of the roller bearing arm 7 is limited by two end positions, which are each detectable. For this purpose, a first signal transmitter 15a for the first end position of the arm, and a second signal transmitter 15b for the second end position of the arm is integrated into the pivot joint. Preferably belongs to each of the two signal generator 15a, 15b, a local thereto slightly upstream pre-signal generator, so that already approaches to the end positions are detectable. Intermediate layers of the arm 7, however, are not sensory detected, but rather a signal is released only when the arm 7 approaches one of its two end positions at least.

Fig. 6 also shows a damping element 16, which operates progressively and exerts a higher damping force on the pivot axis 6 of the arm, the greater the displacement speed of the arm. This damping leads to a calming of the arm with respect to short-wave oscillation amplitudes.

Due to the particularly lightweight construction of the arm 7, the band tension of the guided over sliver 5 is kept constant, also short and long-wave translation changes are well balanced.

The detection signals of the limit switches 15a, 15b are sent to a central control unit, which calculates therefrom a speed change for the basic setting of the can stack 3. Approaches z. As the arm 7 with its role 8 of the lower end position, which is equivalent to a reduction of the sliver length between drafting and caning, a slowing down of the basic speed of the can stack 3 is calculated by the central control unit. Conversely, the arm 7 increases with its role 8, which is equivalent to an elongation of the sliver section between drafting and Kannenstock, the basic speed of the can stack is increased, and thus the driving speed of the can can. For this purpose, the central control unit is connected to a controller, which gives appropriate drive commands, so as to make an adjustment and thus Einjustierung the basic translation of Regulierstreckwerks to can-can. Furthermore, the time interval which has elapsed since the last signal output by the signal transmitters 15a, 15b enters the control loop. The larger this time interval, the lower the adjustments made by the central control unit to the speed of the fuel can drive. This consideration of time data leads to a significant calming of the control behavior, and in this way automatically the optimal basic translation is found.

LIST OF REFERENCE NUMBERS

1

teasel

2

drafting system

3

can Stock

4

Sliver

5

sliver

6

swivel axis

7

poor

8th

role

9

pipe

10

weight element

11

stand

12

adjustment threads

13

Lock nut for the weight element

14

role

15a

signaler

15b

signaler

16

damping

Claims (10)

1. Fibre conveying and depositing device for connection to a carding machine, in which the fibre strip, after exiting from the carding machine, is passed through a draw frame (2) consisting of at least two driven roller pairs and then reaches a can coiler (3), wherein the draw frame (2) has a main drive and a regulating drive for the last roller pair, comprising:

   a. deflection means (8) for the fibre strip (5) arranged between the last roller pair of the draw frame (2) and the can coiler (3), which deflection means can be displaced in order to compensate for the length of the fibre strip;

   b. signal transducers (15a, 15b) for a first and second end position of the deflection means (8), and

   c. means for changing the speed of the can coiler drive when a signal is output by one of the signal transducers (15a, 15b) and as a function of the time interval that has elapsed since the last signal was output,

   characterised by deflection means (8) arranged at the free end of an arm (7) which can pivot about a pivot axle (6) and which exerts a counter-pressure on the fibre strip (5) so as to maintain a certain strip tension, via which deflection means the fibre strip (5) is guided at a deflection angle.
2. Fibre conveying and depositing device according to Claim 1, characterised in that in each case two signal transducers (15a, 15b) are arranged slightly offset with respect to one another in order to detect the two end positions.
3. Fibre conveying and depositing device according to Claim 1 or 2, characterised by proximity switches as signal transducers (15a, 15b).
4. Fibre conveying and depositing device according to one of Claims 1 to 3, characterised by a roller (8) arranged in a freely rotatable manner on the arm (7) as deflection means.
5. Fibre conveying and depositing device according to Claim 4, characterised in that the roller (8) and the arm (7) are prestressed against the fibre strip (5) by means of a weight element (10) arranged on the arm (7).
6. Fibre conveying and depositing device according to one of Claims 4 or 5, characterised in that the pivotable arm (7) consists of a thin-walled tube (9), preferably made from carbon fibre.
7. Fibre conveying and depositing device according to one of Claims 4 to 6, characterised by a further roller (14) which is mounted in a stationary manner on the pivot axle (6) for the arm as further deflection means.
8. Fibre conveying and depositing device according to Claim 7, characterised in that the pivot axle (6) for the arm (7) is arranged above the can coiler (3), and in that the fibre strip (5) is guided vertically between the further roller (14) and the can coiler (3).
9. Fibre conveying and depositing device according to one of Claims 1 to 8, characterised in that the deflection means are provided with a damping element (16) which has a progressive damping characteristic and acts in the direction of displacement.
10. Fibre conveying and depositing device according to Claim 5 in conjunction with Claim 9, characterised in that the damping element (16) acts on the pivot axle of the pivotable arm (7).

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