EP0275471B1 - Method and appliance for the equalization of the fibre web density at the entrance of a textile machine - Google Patents

Description

The invention relates to a method and a device for compensating the density of a fiber wad fed into a textile machine, as defined in the preamble of the first method and the first device claim.

The homogenization of the fiber wadding at the entrance to a textile machine that processes the wadding - also called a mat - is an essential prerequisite for the uniformity of the product delivered by this machine. With increasing processing speed, this prerequisite becomes even more important, since fewer machines are used for the same amount of fiber wadding to be processed, so that the possibility of duplication from a larger number of machines and the resultant equalization of the product becomes smaller.

There is therefore considerable prior art in order to achieve this object, of which the following patent specifications are cited as examples.

From US-A-4275483 a feed means of a card is known, consisting of a fixedly arranged feed plate and a drivable feed roller movably arranged above it. This feed roller is pressed at both ends by means of springs against the fiber wadding located between the feed roller and the trough plate. A similar arrangement is known from DE-A-32 05 776.

The movements of the feed roller resulting from the unevenness in the fiber wool are emitted by sensors provided at both ends of the feed roller as signals to a control unit which calculates the necessary speed change of the feed roller in order to compensate for these unevenness as far as possible.

The main disadvantage of this system is that the feed roller to be driven is also used to scan the unevenness in the fiber wadding, which inevitably leads to interference in the measurement signals, even if precautions are taken in the arrangement of the drive of the feed roller to the directions of the To obtain driving force of the feed roller drive perpendicular to the direction of movement of this roller during the scanning.

This disadvantage is eliminated by the device of FR-A-23 22 943. This suggests a stationary feed roller and scans the unevenness of the cotton to be fed in using a continuous or a trough plate divided into pedals. The trough plate, respectively. the pedals are pivoted so that they can move against or away from the feed roller, thereby eliminating the unevenness to feel the fiber wadding.

A disadvantage of this system is not the measuring principle, but the type of fiber transfer to a subsequent licker-in roller (also called a beater), in that the fiber transfer point on the trough plate (or pedals) moves due to the swiveling of the trough plate relative to the stationary licker-in roller, which means that the position of the transfer point of the fiber wadding from the trough plate (or pedals) to the licker-in roller also moves alternately in the direction of rotation of the licker-in roller and against it, which creates an unrest in the transfer of the fibers to the licker-in roller.

Another example to remedy the disadvantages mentioned first is shown in DE-A-29 12 576, in that a sensor element provided near or adjacent to the fixed trough plate detects the density of the fiber floss lying on the trough plate and signals it outputs a control device to adjust the speed of the feed roller.

The disadvantage of this system is that the density of the fiber wadding is measured before it is drawn in between the trough plate and the feed cylinder, so that changes in the fiber wadding can occur until it is drawn in between the trough plate and the feed cylinder, which then no longer match the measured values would match.

Basically, it should be mentioned that a trough plate and a feed plate as well as a feed cylinder and a feed roller are each the same Elements.

The invention is therefore based on the object of finding a system which detects and corrects the inequalities in the fiber wad density to be fed in easily and yet with sufficient accuracy.

This object is achieved with the inventions defined in the characteristic of the first method and in the characteristic of the first device claim.

The advantages achieved by the invention are that the density of the fiber wadding to be fed in can be determined without the disadvantages mentioned.

Another advantage is also that the measuring point or the measuring plane, respectively. the measuring direction, can be provided such that the determination of the change in thickness of the fiber mat can be carried out close to the narrowest nip between the feed plate and the feed roller, i.e. essentially close to the point at which the fiber mat is taken over by the licker-in roller. This creates a very small distance between the measuring point and the fiber transfer point, i.e. the time of the measurement is very close to the time of the necessary speed correction.

In the following, the invention is explained in more detail with the aid of drawings which only show execution routes. It shows:
1 shows a longitudinal view of a card with a fiber feed means according to the invention, shown schematically,
2 shows the fiber feed means according to the invention from FIG. 1, shown enlarged,
3 shows a variant of the fiber feed means of FIG. 2,
4 parts of the fiber feed means of FIG. 1, shown enlarged,
5 is a plan view of part of FIG. 4,
6 to 29 each variant of the fiber feed means, in a representation with a longitudinal view and a floor plan analogous to FIGS. 4 and 5.
30 shows a rotor-open-end spinning machine with the fiber feed means according to the invention, shown schematically,
31 shows a friction-open-end spinning machine with the fiber feed means according to the invention, shown schematically,
32 shows a drafting system with the fiber feed means according to the invention, shown schematically.
33 the part of FIG. 4 with further details, shown schematically,
34 shows part of the device of FIG. 4, enlarged and shown in section along lines I of FIG. 35,
Fig. 35 shows part of the device of Fig. 4, enlarged and shown in viewing direction II (Fig. 33).

A card 1 comprises from left to right, as seen in FIG. 1, at the card entry a fiber feed means 2, shown with a dash-dotted line, a licker-in roller 3, also called a beater, a reel 4 with a cover 5, a fiber pile take-off roller 6, also called a doffer roll, and a fibrous web compacting unit 7 for forming a card sliver 8.

The fiber feed means 2 comprises a rotatable and drivable feed roller 9, also called feed cylinder, a feed plate 10, also called trough plate, which cooperates with the feed roller and is pivotally mounted about a pivot axis 11.

The feed roller 9 is arranged stationary, and the pivotability of the feed plate 10 is limited by an adjusting screw 12, in the direction of movement away from the feed roller 9, and by a stop mentioned later in the opposite direction.

The feed roller 9 is driven by a gear motor 13.

In operation, a fiber mat 15 is fed to the fiber feed means 2 on a feed plate 14. By rotating the feed roller 9 in the circumferential direction U, the fiber mat is fed in a manner known per se to the much faster rotating licker-in roller than the compressed fiber mat.

The nonwoven fabric processed between the drum 4 and the lid 5 is removed from the doffer roller 6 and passed on to the nonwoven compression unit 7, in which the nonwoven fabric is compressed into the card sliver 8.

The ratio of the peripheral speed of the doffer roller 6 to the peripheral speed of the feed roller 9 gives the so-called draft ratio of the card.

Furthermore, by inserting the fiber mat 15, the food plate 10 is pivoted away from the feed roller 9 until the food plate contacts the set screw 12. This position of the food plate 10 is referred to as the operating position.

With the aid of this adjusting screw 12, the degree of compression of the fiber mat 15 located between the feed plate 12 and feed roller 9 is accordingly determined.

This clamping effect causes measurable variables described later in the fiber feed means 2, by means of which a signal 16 corresponding to the density of the “pinched” fiber mat 15 is continuously obtained.

To obtain the signal 16, as will be described later with reference to FIG. 5, two signals 16A, 16B from left to right on the pivot axis 11 of the feed plate 10 are attached strain gauges, which sense the transverse force of the bearing journal of the feed trough. These signals 16A, 16B are applied to a measuring amplifier 16C, which first adds the signals and then amplifies them, so that the signal 16 is produced, which represents an amplified mean signal. The measuring amplifier 16C converts the signals from the strain gauge transducers into a DC voltage which is between -10 and +10 V.

The signal 16 is input to a controller 17, together with a control signal 18 for the wad thickness, a speed signal 19 of the doffer roller 6 and a speed signal 20 of the geared motor shaft 21, the control signal 18 and that Speed signal 19 of the doffer roller 6 have a predetermined value. The value of the manipulated variable signal 18 can be selected at a decade switch 18A and finally determines the desired band number.

The controller "processes" the aforementioned signals into an output signal 22, by means of which the speed of the geared motor 13 is corrected in accordance with the deviations in the density of the fiber mat 15 in a clamping gap area 23 such that the density of the fiber mat when leaving the Clamping gap area is substantially balanced.

The controller 17 essentially consists of a microcomputer 17A from Texas Instr. Type 990 / 100MA with the necessary number of EPROMS type TMS 2716, also from Texas Instr., For programming the control functions, as well as a control unit 17B type D 10 AKN RV 419D-R from AREG, Federal Republic of Germany, Gemrigheim. The control unit 17B amplifies a speed signal emitted by the microcomputer to the output signal 22 and receives the signal 20 for checking and regulating the feed roller speed.

The run-in signal 16 is first processed in a stage 17C. At regular, short successive intervals, the mean value of the incoming signal is recalculated from a fixed number of the last read values. In this way, if desired, the long-term deviation of the template can be determined (drift filter). At a very short time interval of approximately 100 ms, the instantaneous value of the incoming signal is compared with the mean value in stage 17C and the deviation is communicated to the microcomputer 17A as the actual value. The latter is programmed as a PI controller and uses the control algorithm specified in the EPROMs and preprogrammed device-specific data to calculate a control value x from the setpoint of the decades, which forms the setpoint for the AREG controller 17B and is supplied to it, as schematically by means of the corresponding one Arrow between blocks 17A and 17B is indicated. It is also possible to perform the functions of stage 17C in the microcomputer when installing the corresponding EPROMS, so that a separate stage 17C is not necessary.

The AREG controller represents independent control electronics upstream of the control motor 13. The setpoint specified by the microcomputer 17A is compared in the control electronics with the tachometer actual value 20, the difference is amplified and fed to the motor via the power circuits. The control electronics 17B works as a voltage metering and only supplies the motor with as much voltage 22 as is required to apply the required torque and maintain the speed.

The processes in the nip area 23 are defined by the interaction of the feed roller 9 and the feed plate 10, in that area the fiber mat 15 is pressed from the original thickness D to a thickness (not shown) which it immediately before leaving the area 23 has. The clamping gap region 23 thus ends at the edge of the food plate 10, referred to as the fiber delivery edge 24, at which the fiber mat 15 is no longer clamped by the food plate 10.

The directions of rotation of the feed roller 9, the breeze 3, the reel 4 and the doffer roller 6 are each identified by the arrows U. The fiber material moves through the card in accordance with these directions of rotation.

With the aid of the speed variations of the feed roller 9 caused by the regulation, inequalities in the density of the fiber mat 15 in the nip area 23 are compensated for when the fiber mat passes from the feed plate 10 to a licker-in roller 3.

FIG. 2 shows the fiber feed means 2 from FIG. 1 in an enlarged representation and in somewhat more detail, for which reason the same elements are provided with the same reference symbols.

It can be seen from this figure that the pivot axis 11 is accommodated in a stationary bearing housing 26 belonging to the machine housing 25 (only indicated with hatching).

Also attached to the machine housing 25 is a stop 27 which prevents the feed plate 10 from resting on the feed roller 9 when there is no fiber mat 15.

Likewise, a carrier 28 receiving the set screw 12 and the gear motor 13 are fastened to the machine housing 25.

FIG. 3 shows a variant 2.1 of the fiber feed means from FIGS. 1 and 2, so that the same elements are provided with the same reference symbols.

This variant has a feed plate 29 arranged below the feed roller 9, as seen in FIG. 3, which is pivotably mounted by means of a pivot axis 31 accommodated in a bearing housing 30 fastened to the machine housing 25.

A set screw 32 limits the pivotal movements of the feed plate 29 in a direction away from the feed roller 9, while a stop 33 prevents the feed plate 29 in a direction of movement against the Feed roller 9 can come into contact with this roller, the latter direction of movement of the feed plate 29 being caused by a compression spring 34.

The set screw 32 is received by means of a carrier 35 and the spring 34 by means of a carrier 36 each from the machine housing 25.

The stop 33 is the end face of a feed plate 37, which is also attached to the machine housing 25.

The clamping gap area 23.1 corresponds to the clamping gap area 23 of FIGS. 1 and 2.

In the following, with the help of the other figures, measuring means are defined which are used to generate the signal 16 emitted by the feed means 2.

4, 8, 12, 16, 20 and 24 show elements of the feed means of FIG. 2, while FIGS. 6, 10, 14, 18 and 22 have elements of the feed means of FIG. 3. Accordingly, the same elements are provided with the same reference numerals in the figures mentioned.

5 shows the feed plate 10, the pivot axis 11 and the bearing housing 26 as well as a second bearing housing 26.1 which also receives the pivot axis 11.

The feed plate 10 has two bearing legs 38, by means of which the feed plate 10 is pivotably mounted on the pivot axis 11.

In the spaces between the bearing legs 38 and the bearing housings 26, respectively. 26.1, the pivot axis 11 each has a surface 39 (FIGS. 34 and 35)) for accommodating one strain gauge 90 each. These strain gauges 90 are arranged in such a way that they each generate a signal corresponding to the magnitude of a force F (FIGS. 4, 33 to 35) produced during operation on the feed plate 10, both signals 16A, 16B in the mean value generator 16C (not shown here) ) are converted into the previously mentioned signal 16.

The force F is determined by two force components together, on the one hand from a force component which is caused by the pressure forces generated by the fiber mat in the wedge gap between the feed plate and the feed roller and on the other hand from a force component which arises from the friction forces occurring in the wedge gap.

The total resulting force F _R (is equal to compressive force + frictional force) can be broken down into two components, namely a horizontal component F _H and a vertical component F _V. The vertical force component is relatively small, since the corresponding contributions of the pressure and friction forces point in opposite directions. This component thus changes only slightly when the density of the fiber template changes. In the case of the horizontal force component, on the other hand, the corresponding contributions of the pressure and friction forces add up, so that there is a pronounced dependency here between F _M and the change in density of the fiber template in the clamping gap area. This dependency is exploited according to the invention in that the strain gauges 90 are also essentially placed in a horizontal plane and thus most sensitively determine changes in density of the fiber template in the nip area.

The optimal direction of the force F is roughly horizontal and can be determined by experiment. However, an approximation to this optimal direction is enough to make a sensitive measurement.

33 shows that the force F acting on the pivot axis 11 should be in approximately the same direction, but not necessarily in the same plane as the force F _H.

However, this type of measurement also represents a significant difference from the prior art, in which a relative movement between the feed plate and feed cylinder is used for the measurement. In the latter case, the compressive forces increase with increasing density of the fiber template, but so do the frictional forces, which work against the compressive forces due to the indispensable curvature of the plate around the feed cylinder, so that the measurement cannot be carried out sensitively. It is also not possible in the prior art to overcome this problem by measuring the relative movement in the horizontal plane; here a relative movement is quite undesirable since the changing width of the clamping gap makes the control of the speed of the rotating feed cylinder much more difficult would.

Of course, the horizontal direction is only the preferred direction for the force measurement if the card is designed as in FIG. 1. With a differently designed angular position between the fiber feed means 2 and the lickerin roller 3 (ie approximately the inclination of a plane that the Axes of rotation of the feed roller 9 of the licker-in roller 3 connects to the horizontal plane), the direction of force would have to be selected accordingly.

With Figures 34 and 35 is enlarged and thus shown in more detail than with Fig. 5 that the surface 39 with the strain gauges 90 is the flat base of a bore 91 and that by means of a further, opposite to the aforementioned, mirror-image arranged bore 92 a web 93 emerges as the weakest point. This measurement practice is known in the art and is used, for example, by the Reglus company in Adliswil, Switzerland.

35 also shows the compensation forces F _K1 and F _K2 arising as a result of the force F. The forces F and F _{K1 act in} such a way that the strain gauges 90 essentially reflect the transverse forces in the web 93.

The aforementioned forces are neither shown in the correct proportion nor in the exact direction.

The force measurement method described above also applies to the elements of FIGS. 6 and 7 to be described.

FIG. 7 shows the feed plate 29, the pivot axis 31 and the bearing housing 30 as well as a second bearing housing 30.1 which also receives the pivot axis 31 as a floor plan of FIG. 6.

The feed plate 29 has two bearing legs 40 which receive the pivot axis 31.

In an analogous manner, as described for FIGS. 4 and 5, the pivot axis 31 in the spaces, between the bearing legs 40 and the bearing housings 30, respectively. 30.1, each have a surface 39 for receiving a strain gauge (not shown).

The strain gauges for this variant are also arranged in such a way that they each generate a signal corresponding to the magnitude of a force F.1 (FIG. 6) generated during operation on the feed plate 29, with both signals in a mean value generator (not shown) in the Signal 16 mentioned earlier can be converted.

The force F.1 builds up in an analogous manner to the force F described for FIGS. 4 and 5.

The optimal direction of the force F.1 is also determined by experiments, an approximation to this optimal direction also being sufficiently precise.

The following FIGS. 8 and 9, 12 and 13, 16 and 17, 20 and 21 as well as 24 and 25 show, with the exception of the measuring means for determining the signal 16, the same elements as were shown with FIGS. 4 and 5, which is why they are the same Reference numerals are used for the same elements. The same applies to the following FIGS. 10 and 11, 14 and 15, 18 and 19 and 22 and 23 with respect to the elements shown in FIGS. 6 and 7.

The measuring means of FIGS. 8 and 9 is a load cell 41 assigned to the adjusting screw 12 such that it outputs a signal 16 corresponding to the size of a force F.2 (FIG. 8). This force F.2 is one of the fiber mat 15 present in operation of the clamping gap region 23 mentioned (not in FIG. 8) shown) generated forces resulting force which acts in the direction of the longitudinal axis (not shown) of the adjusting screw 12. The set screw 12 is arranged in the middle of the length L of the feed plate 10. The horizontal distance H, as seen in FIG. 8, of the above-mentioned longitudinal axis up to the fiber delivery 24 is not particularly critical, nevertheless the smallest possible distance H should be sought.

The same applies to a load cell 41.1 assigned to the set screw 32 (FIG. 10), to which a force F.3 acts analogously to the force F.2 of FIG. 8. Also, the set screw 32 is in the middle of the length L and with a horizontal distance H.1, as viewed in FIG. 10, from a fiber deflecting nose 44 on the feed plate 29 to that in the direction of the longitudinal axis (not shown) Set screw 32 acting force F.3.

Fig. 12 respectively. 13 and 14 resp. 15 each show a variant in the use of load cells to determine the density of the fiber mat in the wedge gap area 23 or. 23.1 (not shown in FIGS. 12 and 14) force generated during operation.

For this purpose, the dining plate 10 of FIGS. 12 and 13 in the end face 42 facing the beater 3 (FIG. 2) has a depth T and a height B (FIG. 12) having groove 43. The height B is selected in such a way that load cells 41.2 can be pushed into the groove 43 without play in a position shown in FIGS. 12 and 13 and held in place (not shown).

In operation, the fiber mat 15 (not shown in FIG. 12) located in the wedge gap between the feed plate 10 and the feed roller 9 generates forces which tend to have a feed plate part 60 located between the groove 43 and the fiber-dispensing edge 24 around an inner groove edge 61 to pivot in a direction R. These forces result in a force F.4 acting over the entire length L, which generates a corresponding signal in the load cells 41.2. The signals of the individual load cells are averaged to signal 16 in an averager (not shown).

The variant shown with FIGS. 14 and 15 functions with respect to the generation of signal 16 essentially the same as described with reference to FIGS. 12 and 13, which is why the elements necessary for generating signal 16 are provided with the same reference numerals as 12 and 13, with the exception of the force F.5, which, because of the different type of fiber transfer via the nose 44 of the feed plate 29 to the briseur 3, has a different size than the force F.4 of FIG. 12, in which the fibers are transferred from the feed roller 9 to the breeze 3 in so-called synchronism. The synchronism arises from the fact that the feed roller 9 and the beater 3 have the same direction of movement at the fiber transfer point (see FIG. 1). However, other factors can play a role in the formation of the force component F.5, such as the shape of the food plate 10 or. 29 in the area 23 resp. 23.1 and the distance of the groove edge 61 from the fiber mat 15 leading surface of the food plate 10, respectively. 29. The same is true The invention is not restricted to the number and arrangement of the load cells shown in FIGS. 13 and 15. It is understood that, for example, depending on the strength of the groove 43 to the fiber release edge 24 (FIG. 12) or. one, two or more load cells 41.2 extending up to the nose 44 (FIG. 14) can be provided.

16 and 17, the measuring means consists of three load cells 41.3 which are arranged in a groove 45 which is embedded in the feed plate 10 and opens into the clamping gap region 23 (FIGS. 1 and 2) in the clamping gap.

In order to transmit the force component F.6 produced by the fiber mat located in the clamping gap and acting over the entire length L to the load cells 41.3, these load cells are covered by a force transmission bar 46 which completely grooves 45 and without any annoying deflection of the shape of the food plate completes completely customized.

The signals emitted by the individual load cells 41.3 are converted into signal 16 in an averager (not shown).

The distribution of the aforementioned load cells in the groove 45 is essentially as shown in FIG. 17. However, it is understood that the number of load cells is not limited to the three shown. For example, in the case of a force transmission beam designed with the corresponding strength, only two load cells can be used, whereas if the force components are determined more precisely over the length L (FIG. 17) the food plate 10 is to be detected, a larger number of load cells can be distributed.

18 and 19 is composed of a membrane 47 inserted into the feed plate 29, a pressure converter 48 and a pressure fluid system 49 connecting the membrane 47 to the pressure converter 48.

A force component F.7 (FIG. 18) analogous to the force F.6 of FIG. 16 causes a pressure on the diaphragm 47, as a result of which a force transmission is transmitted via the hydraulic fluid system 49 to the pressure converter 48, which is a force F. 7 corresponding signal 16 is generated.

20 and 21 is based on the knowledge that when the fiber mat 15 is inserted into the wedge gap between the feed plate 10 and the feed roller 9, i.e. in the wedge gap area 23, due to the increasingly narrowing clamping gap, air is displaced from the fiber mat.

The displacement of this air is opposed by the resistance of the fiber mat itself, so that an increasing overpressure in the fiber mat arises in the fiber mat 15 in the direction of the fiber delivery edge 24, the resistance of the density of the fiber mat and the amount of air to be displaced correspondingly different.

This overpressure is recorded with the measuring means shown in FIGS. 20 and 21, in that a measuring groove 50 is let into the food plate 10, which is inside the feed plate 10 is connected to a pressure transducer 53 via a pressure line 51 and a pressure line 52 connected to the feed plate 10. This pressure converter 53 converts the excess pressure determined in the measurement groove 50 into the signal 16.

21, the measurement groove 50 is not continuous over the entire length L, i.e. the length L.1 of the measuring groove 50 is shorter than the length L of the feed plate 10, so that the measuring groove 50 is a groove located in the clamping gap area 23 and only open against the clamping gap.

As shown in FIG. 20, the measurement groove forms an acute angle α with an imaginary plane E, which includes the mouth edge 54 of the wall 55 of the groove 50 as a tangential plane. This arrangement prevents a fiber jam from occurring in the groove 50. The angle α has a maximum of 30 degrees.

22 and 23 show one of the measurement grooves 50 of FIGS. 20 and 21 analog measurement groove 50.1 with a pressure line 51.1 connected to it and a pressure line 52.1.

In contrast to the measuring means of FIGS. 20 and 21, the measuring means of FIGS. 22 and 23 not only measure the pressure which, as described, arises from the air being pressed out of the fiber mat, but also a constant pressure source 56 The amount of compressed air is pressed into the compacting fiber mat using measuring groove 50.1. The enforcement of this predetermined amount of compressed air the fiber mat occurs against the resistance of the fiber mat, so that a pressure corresponding to this resistance is transmitted from the pressure lines 51.1 and 52.1 to a pressure transducer 53.1 connected to the pressure line 52.1.

Since the resistance changes with the density of the fiber mat in the clamping gap area 23, the pressure in the lines 51.1 and 52.1 also changes. The pressure converter 53.1 converts these pressure variations into the signal 16.

As can be seen from FIG. 22, the measurement groove 50.1 also has the angle α described for FIG. 20.

FIGS. 24 and 25 show a variant of the measuring means of FIGS. 22 and 23, in that the quantity of compressed air which is constant from the compressed air source 56.1 is blown into the fiber mat located in the wedge gap area 23 by means of an injection groove 58. This air travels in this fiber mat in a direction W opposite to the direction of rotation of the feed roller until it can escape into the atmosphere through a ventilation groove 59 and a ventilation line 57 connected to it.

A pressure transducer 53.2 is connected to the pressure line 52.2. This pressure converter 53.2 converts the pressure existing in the pressure line 52.2 into the signal 16. A resistance range can be defined with the distance M between the injection groove 58 and the ventilation groove 59.

FIGS. 26 and 27 show a variant 2.2 of the fiber feed means from FIG. 2, in that the feed plate 10 can not only be pivoted about the pivot axis 11, but that it can also be pivoted about a pivot axis 62, which is coaxial with the axis of rotation of the feed roller 9 lies. This pivotability is shown schematically with the radius arrow S.

In order to enable this pivotability, a holding bracket 63 is provided which has two legs 64 (only one visible in FIG. 26), in which the pivot axis 11 is mounted.

These legs are connected to a web 65 which is continuous under the food plate 10 (viewed with a view of FIG. 26) and serves to receive the stop 27.

Furthermore, the legs 64 each have a guide slot 66, the lower guide surface 67 (seen with a view of FIG. 26) has a curvature with the radius S. The upper guide surface 68 opposite the lower guide surface 67 is provided parallel to the guide surface 67.

These guide slots 66 each serve to receive two guide pins 69, which are fixedly arranged in a machine housing part 70. The distance (not marked) of these two guide pins 69 is selected in relation to the length (not marked) of the guide slot 66 such that the holding bracket 63 can be pivoted about the pivot axis 62 for a given pivot length (not marked).

In order to hold the holding bracket 63 in a selected pivot position, it is held in place by means of two screws 71 screwed into the machine housing part and projecting through the guide slot 66.

Furthermore, the set screw 12 is arranged on an end part 63.1 of the holding bracket 63 directed against the licker-in roller 3.

It goes without saying that this variant can also be used to combine all of the elements shown in FIGS. 4 to 25 in order to generate the signal 16. The application of these elements in connection with this variant is therefore not repeated.

28 and 29 show a variant 2.3 of the feed means of FIG. 3, in that a feed plate 72 is fixedly connected to the machine housing 25, while the feed roller 9 is movable in a given area.

This mobility of the feed roller 9 is given by the fact that the free ends 73 of the feed roller 9 projecting on both sides (only one shown with FIG. 28) of the feed roller 9 are accommodated in a bearing bush 74, which is between two stationary sliding guides 75 and. 76 are guided.

The displacement range of the feed roller 9 is limited on the one hand by a stationary stop 77 and by an adjusting screw 78 which is received in a carrier 79 which in turn is attached to the machine housing 25. The stop 77 has the same function as the stop 27 described earlier.

In operation, the fiber mat 15 on the feed plate 72 is slidably moved from the feed roller 9 into the wedge gap between the feed roller 9 and the feed plate 72, whereby the feed roller 9 from its starting position, in which the bearing bushes 74 each rest on the corresponding stop 77, until they enter the operating position are raised, in which the bearing bushes 74 each abut the adjusting screws 78.

It goes without saying that with the variant shown with these figures, the elements shown with FIGS. 8 to 25 can be used to generate the signal 16.

FIG. 30 shows an application of the feed means of FIG. 1 in a rotor open-end spinning machine.

Since these spinning machines are a method which is known per se, only the essential elements are indicated schematically in order to show the relationship between the feed means and the spinning machine. Accordingly, elements previously described are provided with the same reference numerals.

In operation, the feed roller 9 transfers a fiber sliver 15.1 to an opening roller 80, which transfers these individual fibers to a fiber feed channel 81, which feeds these fibers into a rotor 83 rotating about an axis of rotation 82. In this rotor 83, a yarn 84 is formed in a manner known per se, which is drawn off by a pair of draw-off rollers 85.

The default ratio in the one shown with this figure Spinning machine lies between the peripheral speed of the feed roller 9, given by the speed of the geared motor shaft 21 and by the peripheral speed of the take-off rollers 85, given by the speed of the take-off rollers generating the speed signal 19.1.

Furthermore, it goes without saying that, although the same elements are provided with the same reference numerals, in practice the dimensions of these elements can be of different sizes, since a rotor-open-end spinning machine unit is a substantially smaller textile machine unit than that with Fig 1 card shown schematically.

It is also understood that the feed unit shown with FIG. 3 can be combined with the rotor open-end spinning unit shown with FIG. 30.

Furthermore, it is also self-evident that all the variants shown in FIGS. 4 to 27 in order to generate the signal 16 can be combined with the rotor-open-end spinning machine unit shown in FIG. 30.

FIG. 31 shows a further application variant in which the feed element 2 feeds fibers of an opening roller 80 analogously to the feed element of FIG. 30.

The difference to the textile machine of FIG. 30 in FIG. 31 is that it is not a rotor-open-end spinning machine unit, but a friction-open-end spinning machine unit.

Accordingly, the same elements are provided with the same reference numerals.

In operation, the feed roller 9 feeds the sliver 15.1 to the opening roller 80, which transfers the separated fibers to a fiber feed channel 86 connected to them. With the aid of this fiber conveying channel 86, the free-flying fibers are transferred to a friction spinning drum 87, on which a yarn 88 forms within a yarn formation area G, which yarn is drawn off by a pair of take-off rollers 89.

In FIG. 31, for the sake of simplicity, only one friction spinning drum 87 is shown, but it is known per se that, as a rule, a counter drum is used in this spinning method, which is provided parallel to the drum shown.

Furthermore, analogously to the description for FIG. 30, it goes without saying that the type of feed element shown in FIG. 3 can also be used with such a friction spinning unit and that all variants shown in FIGS. 4 to 27 can be used, to generate signal 16.

FIG. 32 shows a drafting system in which a variant 2.4 of the feed means shown in FIG. 1 is used. In this variant, a counter roller 101 is used instead of the feed plate 10 shown in FIG. 1. This counter roller 101 forms, together with the feed roller 9, the nip.

In contrast to the feed roller 9, the counter roller 101 is not driven, ie is freely rotating and is dragged through the fiber mat 15 lying between the counter roller and the feed roller.

The counter roller 101 is pivotally attached to a pivot lever 102.

The other elements known from the description for FIG. 1, which can be used in an analogous manner in this variant, are accordingly provided with the same reference numerals. It follows that, for example, the pivot lever 102 is pivotally mounted by means of the pivot axis 11 and the bearing housing 26.

The load cell 41 described with FIGS. 8 and 9 is used as the measuring means for generating the signal 16. Reference is therefore made to the description for FIGS. 8 and 9.

The roller pairs identified by reference numerals 103 and 104 are best known from drafting technology and are therefore not described further. It should only be mentioned in connection with the function of the feed means that the two lower rollers (seen with a view of FIG. 32) of the roller pairs 103 and 104 are driven at a fixed speed which results in the draft in the drafting system. The upper rollers of the roller pairs 103 and 104 are also dragged from the fiber mat in an analogous manner to the roller 104.

The draft ratio of the spinning machine shown with this figure lies between the peripheral speed of the feed roller 9, given by the speed of the Geared motor shaft 21 and by the peripheral speed of the lower roller 104, given by their speed generating the speed signal 19.2. The signal 19.2 has the same function as the signals 19.1 in FIGS. 30 and 31 and the signal 19 in FIG. 1.

Accordingly, elements that have the same functions as previously described have the same reference numerals.

An advantage of the inventive setting of the clamping gap to the density of the intermediate fiber mat 15 and. To measure the intermediate sliver 8, in comparison to the known measurement of the clamping gap width changed by said density, lies in the fact that the measurement signals have a correspondingly large amplitude due to the intense force variations.

Another advantage is that the hysteresis inherent in the displacement measurements is eliminated in the force measurement.

Claims (29)

1. Method of evening out the density of a fibre batt (15) or fibre sliver (15.1) fed into a textile machine by a feed means by generation of a signal (16) dependent upon the density of the fibre batt (15) or fibre sliver (15. 1) located in tile feed means (2; 2. 1; 2.2; 2.3; 2.4) and use of this signal (16) to influence the feed speed of the feed means (2; 2. 1; 2.2; 2.3; 2.4), characterised in that the feed means (2; 2. 1; 2. 2; 2. 3; 2. 4) has a predetermined clamping nip which is constant in operation and in that the signal (16) is generated in dependence upon the fibre density in this nip.
2. Method according to claim 1 or 28, characterised in that the feed means (2; 2. 1; 2.2; 2.3; 2.4) comprises a feed roll (9) and a feed element (10,29,63,72, 101) cooperating therewith, and in that the feed speed is the speed of rotation of the feed roll (9).
3. Method according to claim 2, characterised in that the feed element comprises a feed plate (10,29,63,72).
4. Method according to claim 2, characterised in that the feed element includes a freely rotating cooperating roll (101).
5. Method according to claim 1 or 28, characterised in that the signal (16) is generated from the resistance presented to an air stream flowing through the fibre batt (15) or fibre sliver (15. 1) located in the clamping nip.
6. Method according to claim 5, characterised in that the air stream is generated by displacement of air from the fibre batt (15) or fibre sliver (15. 1) moving towards the narrowest point of the clamping nip.
7. Method according to claim 6, characterised in that the air stream is additionally generated by a an air stream blown through the fibre batt (15) or fibre sliver (15.1) moving towards the narrowest point of the clamping nip.
8. Method according to claim 5, characterised in that the signal (16) is generated from the resistance of part of the batt length located in the clamping nip.
9. Method according to claims 3 and 8, characterised in that the batt length is given in the peripheral direction of the feed roll by a predetermined section and by the length of the feed roll.
10. Method according to claim 1 or 28, characterised in that the signal is generated from a force arising from the fibre density in the clamping nip.
11. Method according to claim 10, characterised in that the force is transmitted mechanically to a force measuring means in which an electrical signal is generated.
12. Method according to claim 10, characterised in that the force is transmitted hydraulically to a force measuring means in which an electrical signal is generated.
13. Method according to any one of the preceding claims, characterised in that the signal (16) is evaluated in a control (17) to give a signal (22) controlling the speed of revolution of the feed roll (9).
14. Method according to any one of the preceding claims, characterised in that the textile machine is a staple-fibre card or wool card or an open-end rotor spinning machine or an open-end friction sinning machine.
15. Apparatus for performing the method according to claim 1 or 28, with a feed means (2; 2. 1; 2.2; 2.3; 2.4) comprising at least one drivable feed roll (9) for moving the fibre bait (15) or fibre sliver (15. 1) into the textile machine and a feed element (10, 29,03,101) cooperating with the feed roll to form a clamping nip for the fibre batt, together with

    - a measuring means to determine the density of the fibre batt (15) in the nip and to deliver a measuring signal (16) corresponding to the density, characterised in that,

    - the feed roll (9) or

    - the feed element (10,29,63,72,101) is movable from a starting position into an operating position, which is

    - defined by an adjustable setting element (12,78), while the feed element (10,29,63,72,101) or the feed roll (9) is stationary, to form in operation a constant clamping nip between the feed roll (9) and feed element.
16. Apparatus according to claim 15, characterised in that the feed element (10,29,63) comprises a feed plate (10,29) pivotable around a pivot axis (11,31) and the adjustable setting element comprises at least one set-screw (12) engaged by the feed plate in operation to limit the clamping nip.
17. Apparatus according to claim 15, characterised in that the feed element includes a stationary feed plate (72) and in that the feed roll (9) is movable from a starting position into an operating position which is defined by an adjustable setting element (78).
18. Apparatus according to claim 15, characterised in that the feed element comprises a roll (101) pivotable about a pivot axis (11) and the adjustable setting element comprises at least one set-screw (12) which limits the pivotal movement of the roll (101) to limit the clamping nip.
19. Apparatus according to claim 16, characterised in that the measuring means comprises two elongation measuring strips (not shown) secured at a spacing relative to each other on the pivot axis, which determine the transverse force caused by the feed plate in the pivot axis and emit a corresponding electrical signal (16).
20. Apparatus according to claim 16 or 18, characterised in that the measuring means is at least one force measuring unit (41,41. 1) which as a part of the set-screw (12, 12. 1,32) determines the force generated in the nip and exerted on the set-screw (12, 12. 1, 32) and emits a corresponding electrical signal (16).
21. Apparatus according to claim 16 or 17, characterised in that the measuring means comprises at least one force measuring unit (41.2) so mounted in a play-free manner in a groove (43) provided in the feed plate (10,29) that the force generated in the clamping nip is transmitted at least with a proportional component to the force measuring unit (41.2) and this emits a corresponding electrical signal (16).
22. Apparatus according to claim 16 or 17, characterised in that the measuring means comprises at least two force measuring units (41.3) resting on the base of a groove (45) provided in the feed plate (10) and opening into the nip, the measuring units being convered by a force transmitting beam (46) engaging the force measuring units (41.3) and forming with its face directed towards the nip a port of the surface of the feed plate forming the nip such that the force transmitted by the beam (46) to the measuring units (41.3) causes a corresponding electrical signal (16).
23. Apparatus according to claim 16 or 17, characterised in that the measuring means comprises a membrane (47) substantially integrated into the feed plate (29) over the length thereof and in the surface forming the nip, and also a pressure converter (48) to which force applied to the membrane (47) is transmitted hydraulically and which emits a corresponding electrical signal (16).
24. Apparatus according to claim 16 or 17, characterised in that the measuring means comprises a groove (50) provided in the feed plate (10), opening into the nip, extending substantially over the length (L) of the feed plate and arranged parallel to the pivot axis (11) of the feed plate (10), together with a pressure converter (53) connected to this groove, the groove (50) by way of the groove wall (55) facing the pivot axis including with the clamping nip surface of the feed plate (10) an angle of at most 30°, and in that the pressure converter (53) emits a signal (16) corresponding to the pressure in the groove.
25. Apparatus according to claim 16 or 17, characterised in that the measuring means comprises

    - a groove (5O. 1) provided in the feed plate (29), opening into the nip, extending substantially over the length (L) of the feed plate (29) and arranged parallel to the pivot axis (31) of the feed plate (29) or to the axis of rotation of the feed roll (9),

    - and a pressure converter (53 . 1) connected to this groove (50. 1).

    - and a compressed air source (56) with constant air flow connected to the groove (50. 1),

    - the groove (50. 1) by way of the groove wall (55.1) facing the pivot axis (31) including with the nip surface of the feed plate an angle of at most 30° and

    - the pressure converter (53.1) emitting a signal corresponding to the pressure in the groove (50.1).
26. Apparatus according to claim 16 or 17, characterised in that the measuring means comprises first and second grooves each provided in the feed plate (10), opening onto the nip, extending substantially over the length (L) of the feed plate (10) and arranged parallel to the pivot axis (11) of the feed plate (10), the first groove being a blowing-in groove (58) and the second groove being a venting groove (59), each groove by way of its groove wall facing the pivot axis including with the clamping nip surface of the feed plate an angle of at most 30°, and in that the first groove is located at a predetermined spacing (M) from the second groove, and in that the first groove (58) is connected to a compressed air source (56.1) of constant air flow and to a pressure converter (53.2) which emits a signal (16) corresponding to the pressure, while the second groove (59) is connected to atmosphere.
27. Apparatus according to the preceding claims 15 and 19 to 26, characterised in that the pivot axis (11) of the feed plate (10) is pivotable and retainable within a predetermined range around the pivot axis (62) of the feed roll (9).
28. A method of generating a signal (18) dependent upon the density of a fibre batt (15) or fibre sliver (15.1) fed by a feed means to a textile machine, and the use of the signal (16) to influence the feed speed of the feed means (2: 2.1: 2.2: 2.3: 2.4), characterised in that the feed means (2:2.1:2.2: 2.3: 2.4) has a predetermined clamping nip which Is stationary in operation, and in that the signal (16) is generated in dependence upon the fibre density in this clamping nip.
29. A method according to claim 3, characterised in that the signal is detected close to, but in front of that point at which the feed element transfers the fibre batt to the element which takes the fibre batt over.

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