Method and apparatus for making a uniform, continuous sliver

An apparatus for making a uniform, continuous sliver has a sliver sensor for continuously sensing the throughput quantity of the sliver and generating a continuous main regulating signal x as a function of the throughput quantity and a first regulator connected to the sliver sensor for receiving the signal x and generating a reference signal w.sub.h as a function of the signal x. The apparatus further has a tuft column sensor connected to a tuft shaft of a card for sensing a variable of the tuft column advancing in the tuft shaft. The tuft column sensor has a signal generator for emitting an auxiliary regulating signal x.sub.h as a function of the sensed variable of the tuft column and a desired value setter which receives the signal w.sub.h and varies the signal x.sub.h as a function of the signal w.sub.h. Further, the apparatus has a tuft column altering arrangement including a second, auxiliary regulator which receives the signal x.sub.h and applies a setting signal y to a card feeder for altering the tuft column as a function of the signal x.sub.h.

BACKGROUND OF THE INVENTION 
This invention relates to a method and an apparatus for making a uniform, 
continuous sliver, wherein the tuft column is measured in a tuft shaft as 
a function of a deviation which, in turn, is measured at the running 
sliver supplied by the tuft shaft. 
In a known method of the above-outlined type, a signal representing the 
deviation of the sliver weight from a desired value is applied to a 
regulator which accordingly varies the rpm of a blower generating a 
pressure in a sole tuft shaft. With this method, sliver fluctuations may 
be measured, for example, downstream of the carding machine. The setting 
member and the blower are located externally of the tuft shaft. This 
process has the disadvantage that the regulator output affects a 
continuously operating setting member; consequently, the pressure 
difference prevailing in the tuft shaft varies continuously. Further, in 
the above-outlined method, only in case of a continuously operating 
setting member can the regulation be effected beyond a predetermined 
deviation from a desired value. It is a further disadvantage of the 
above-outlined method that its application is limited to an arrangement of 
the setting member externally of the tuft shaft and thus it is limited to 
a regulation of the pressure drop in a single tuft shaft. 
SUMMARY OF THE INVENTION 
It is an object of the invention to provide an improved method of the 
above-outlined type wherein the regulator output admits a non-continuous 
alteration of the tuft column, wherein the alteration is effected beyond a 
predetermined deviation from a desired value and which may find 
application in a tuft feeding apparatus having an upper and a lower tuft 
shaft. 
This object and others to become apparent as the specification progresses, 
are accomplished by the invention, according to which, briefly stated, the 
method of making a uniform, continuous sliver includes the steps of 
sensing, as a function of a deviation, a variable of an advancing tuft 
column in a tuft shaft of a card feeder; generating a first regulating 
signal x.sub.h as a function of the sensed magnitude of the variable; 
applying the signal x.sub.h to a first regulator; generating a setting 
signal y in the first regulator as a function of the signal x.sub.h ; 
applying the signal y to the card feeder for varying the tuft quantities; 
setting a desired value for the first regulator by a reference signal 
w.sub.h ; continuously sensing a variable of an advancing sliver 
continuously formed of the advancing tuft column; generating a second 
regulating signal x as a function of the magnitude sensed in the preceding 
step; applying the signal x to a second regulator; and generating the 
signal w.sub.h in the second regulator as a function of the signal x. 
By providing that the tuft quantities are altered in the tuft shaft, a 
non-continuous alteration of the tuft column may be effected. Thus, the 
tuft quantities may be regulated by energizing and de-energizing the tuft 
feed devices associated with the tuft shaft, so that the method may find 
application in a tuft feeding apparatus having an upper and a lower tuft 
shaft, wherein the tufts are directly introduced into the lower tuft 
shaft. By setting the desired value of the first regulator (hereafter the 
auxiliary regulator) by means of a varying reference value, it is feasible 
to effect a non-continuous alteration of the tuft column beyond a 
predetermined deviation from the desired value. Thus, the method according 
to the invention makes possible an elimination of long-period sliver 
oscillations by regulation and, at the same time, a regulation of the 
non-continuous alteration of the tuft column may be effected in an 
advantageous manner beyond a predetermined deviation from the desired 
value. 
Expediently, the maximum regulator output is sensed at the lower tuft 
shaft; preferably, as the first regulating signal (hereafter the auxiliary 
regulating signal) there is utilized an electric signal derived from the 
pressure prevailing in the lower tuft shaft. 
The non-continuous alteration of the tuft quantity may be effected in a 
simple manner by generating a digital signal as the setting signal, 
applied to the drive means of the feeding roll associated with the lower 
tuft shaft. 
For eliminating the long-period sliver oscillations by regulation, 
preferably the output rate (quantity/time) of the carding machine is 
utilized. The desired value setting of the auxiliary regulator is 
expediently effected in the zone where the magnitude for the auxiliary 
regulating signal is sensed. 
The invention further relates to an apparatus for performing the 
above-outlined method. The apparatus has an auxiliary measuring member 
operatively connected, by means of an auxiliary regulator, with a setting 
member for altering the tuft column in the tuft shaft and further, a 
sliver quantity measuring member is connected, by means of a regulator, 
with a desired value setting member for controlling a reference signal for 
the auxiliary measuring member. 
Advantageously, the auxiliary measuring member is a pressure-responsive 
precision sensor arranged in the lower tuft shaft. In order to effect a 
non-continuous alteration of the tuft quantities in a structurally simple 
manner, the feeding roll for the lower tuft shaft constitutes itself the 
setting member. In order to eliminate the long-period sliver oscillations, 
the measuring member is arranged preferably downstream of the carding 
machine. 
Expediently, a digital regulator, particularly a three-point regulator is 
used as the regulator; this results in an economical manufacture of the 
apparatus. 
In order to sense deviations from the desired value rapidly and in a simple 
manner, an optical and/or acoustic indicator is connected to the 
regulator. Advantageously, to the regulator there is connected a recorder 
such as a multi-color dot plotter to make possible the observation of the 
sliver control over long periods. 
Expediently, a setting motor is used as the desired value setter. To ensure 
that the reference value for the auxiliary measuring member is 
predetermined in a secure manner, according to a preferred embodiment of 
the invention, the setting motor varies the distance between a diaphragm 
and an inductive switch.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
Turning now to FIG. 1, a fine opening stream introduces textile fiber tufts 
in an upper tuft shaft 1 (material storage shaft) and a lower tuft shaft 2 
(feeding shaft) of a card feeder. The latter introduces the textile fiber 
tufts as a web into the carding machine 3. The web discharged by the 
carding machine 3 is combined into a sliver by a sliver funnel 4. 
An electronic pressure-responsive precision sensor switch 9, functioning as 
an auxiliary measuring member, is mounted on a wall of the lower tuft 
shaft 2. The switch 9 is coupled, by means of an auxiliary regulator 10, 
such as a two-point regulator, with the drive 11a of the feeding roll 11 
provided for the lower tuft shaft 2. 
The sliver funnel 4 arranged downstream of the carding machine 3 
simultaneously functions as a measuring member for the sliver 5. The 
sliver funnel 4 is connected with a regulator 7, such as a three-point 
regulator, by means of a conduit 6 through which signals are applied to 
the regulator 7. The three-point regulator 7 is connected by means of an 
electric conductor with a setting motor 8 which is mechanically directly 
connected with the pressure-responsive precision switch 9. In operation, 
the switch 9 measures the pressure prevailing in the lower tuft shaft 2. A 
digital electric signal is, as an auxiliary regulating signal x.sub.h 
derived from the pressure prevailing in the lower tuft shaft 2. The signal 
x.sub.h is applied to the two-point regulator 10 which, in response, 
generates a setting output signal y. The latter is applied to the drive 
11a of the feeding roll 11. By energizing or de-energizing the feeding 
roll 11, there is achieved a non-continuous alteration of the tuft 
quantities in the lower tuft shaft 2. 
The long-period fluctuations of the running sliver 5 are continuously 
sensed by means of the sliver funnel 4 which emits a pneumatic signal x 
representing the deviation of the actual value. The signal x which is the 
main regulating signal, is the input for the three-point regulator 7 where 
it is compared with the predetermined desired value w. In response to this 
comparison, the three-point regulator 7 emits a digital signal 
constituting the reference output signal w.sub.h which serves for setting 
the desired value at the pressure-responsive precision switch 9 by means 
of the setting motor 8. In this manner, the output of the three-point 
regulator 7 effects the desired value setting of the two-point regulator 
10. 
Turning now to FIG. 2, the setting motor 8 has an output shaft 8a carrying 
a pinion 8b which, in turn, meshes with a spur gear 12 having an axial 
sleeve 12a. The latter has an inner thread which cooperates with a 
complemental outer thread provided on an inductive switch member 13 
(electronic proximity switch) which is situated within the spur gear 
sleeve 12a and which forms part of the pressure-responsive precision 
switch 9. Thus, when the signal w.sub.h is applied to the motor 8, it 
rotates the spur gear 12a which causes the inductive switch 13 to shift, 
thus changing the distance 14 between the right-hand end (as viewed in 
FIG. 2) of the inductive switch 13 and a diaphragm 15 arranged in an 
opening of the wall of the lower tuft shaft 2 and displaceable in response 
to the tuft column pressure in the lower tuft shaft 2. 
The diaphragm 15 which is arranged perpendicularly to the axis of and at a 
distance from the switch member 13, is made of an elastomer and is, on its 
side oriented away from the lower tuft shaft 2, provided with a metal 
plate 16 which serves as the seat for a compression spring 17 (arranged 
coaxially about the switch member 13) and as a control member for varying 
the flux density for the switch member 13. The reference output w.sub.h is 
applied to the pressure-responsive precision switch 9 for causing the 
latter to simultaneously function as the desired value setting means for 
the two-point regulator 10.In case of an increasing pressure exerted on 
the diaphragm 15, the latter, together with the metal plate 16, moves to 
the left (as viewed in FIG. 2) while deforming the compression spring 17. 
Thus, upon reaching a set setting pressure, the metal plate 16 enters into 
the switching zone of the inductive switch member 13. A conventional 
thyristor contained in the switch member 13 fires and generates a voltage 
across the output of the switch member 13. In case the pressure drops 
below the set switch-on pressure, the thyristor opens; as a result, the 
voltage across the output of the switch disappears again. This electronic 
pressure-responsive precision switch 9 constitutes a component of a 
regulator system; the diaphragm 15 is the measuring member of this 
regulator system. By means of the pressure-responsive precision switch 9 a 
two-point regulation can be effected in which thus, upon exceeding a 
predetermined pressure, a switch-on or switch-off operation is performed. 
In this manner a digital electric signal is obtained as the auxiliary 
regulating signal x.sub.h from the pressure in the tuft shaft 2. 
In order to sense deviations from the desired value rapidly and in a simple 
manner, an optical indicator 18 and/or an acoustic indicator 19 is 
connected to the regulator 7. Advantageously, to the regulator 7 there is 
connected a recorder 20, such as a multi-color dot plotter to make 
possible the observation of the sliver control over long periods. 
It will be understood that the above description of the present invention 
is susceptible to various modifications, changes and adaptations, and the 
same are intended to be comprehended within the meaning and range of 
equivalents of the appended claims.