GB2081758A - Regulating Apparatus for Automatically Controlling the Evenness of the Linear Density of a Sliver - Google Patents
Regulating Apparatus for Automatically Controlling the Evenness of the Linear Density of a Sliver Download PDFInfo
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- GB2081758A GB2081758A GB8026266A GB8026266A GB2081758A GB 2081758 A GB2081758 A GB 2081758A GB 8026266 A GB8026266 A GB 8026266A GB 8026266 A GB8026266 A GB 8026266A GB 2081758 A GB2081758 A GB 2081758A
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- pulse
- output
- input
- sliver
- pulses
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- D—TEXTILES; PAPER
- D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
- D01H—SPINNING OR TWISTING
- D01H5/00—Drafting machines or arrangements ; Threading of roving into drafting machine
- D01H5/18—Drafting machines or arrangements without fallers or like pinned bars
- D01H5/32—Regulating or varying draft
- D01H5/38—Regulating or varying draft in response to irregularities in material ; Measuring irregularities
- D01H5/42—Regulating or varying draft in response to irregularities in material ; Measuring irregularities employing electrical time-delay devices
Abstract
A regulating apparatus for automatically controlling the linear density of a sliver comprises a pulse train forming means (18), the number of pulses in the pulse trains depending on the linear density of the sliver (4) fed to a drafting assembly, a disc (14) having transparent and opaque areas, kinematically coupled to the sliver driving means and positioned between a light source (12) and a photoelectric transducer (13). The regulating apparatus further comprises a pulse counter (25) having its counting input (26) connected to the output of the pulse train forming means (18) and its output connected via storage devices (29) to the control means (8) for adjusting the speed of the delivery rollers (6) of the drafting assembly. The output of the photoelectric transducer (13) is connected to the synchronizing input of the pulse train forming means (18) and to the control inputs (31) of the storage devices (29) to delay the application of a signal from the output of the counter (25) to the control means (8) for a time period corresponding to the duration of the pulse at the output of the photoelectric transducer (13). The invention may be used in carding, combing and drawing textile machines. <IMAGE>
Description
SPECIFICATION
Regulating Apparatus for Automatically
Controlling the Evenness of the Linear Density of a Sliver
The present invention relates to regulating means for textile machines, and more particularly to regulating apparatuses for automatically controlling the evenness of the linear density of a sliver.
The present invention can most advantageously be used in carding, combing and drawing texti!e machines provided with a drafting assembly.
The invention provides a regulating apparatus for automatically controlling the evenness of the linear density of a sliver by means of a drafting assembly, comprising a sensing means responsive to the linear density of the sliver and positioned ahead of the feed rollers of the drafting assembly, a control means for adjusting the rotational speed of the delivery rollers of the drafting assembly, and a delay means connected between the sensing means and the control means, wherein the delay means, according to the invention, includes a radiation source, a photoelectric transducing means positioned in the path of the beam produced by the radiation source, a disc rotatably positioned between the radiation source and the photoelectric transducing means and kinematically coupled to the sliver driving means, said disc having transparent and opaque areas alternately disposed along the circumference of the disc for developing at the output of the photoelectric transducing means a sequence of pulses, the duration of the pulses varying according to variation of the movement speed of the sliver, a pulse train forming means having a synchronizing input connected to the output of the photoelectric transducing means for developing a pulse train having a limited number of pulses upon application of a pulse from the output of the photoelectric transducing means to the synchronizing input of the pulse train forming means, the repetition period of the pulses in said pulse train being much smaller than the duration of the pulses developed at the output of the photoelectric transducing means, and connected to the sensing means for varying the number of pulses in the developed pulse trains according to the linear density of the sliver, a pulse counter having its counting input connected to the output of the pulse train forming means, a reset means synchronized with the pulse train forming means and connected to the reset input of the pulse counter for resetting the pulse counter before the pulse train developed by the pulse train forming means is applied to the counting input of the pulse counter, a plurality of controlled storage devices respectively connected to the bit position outputs of the pulse ccunter and having their control inputs connected to the output of the photoelectric means for storing information from the corresponding bit position outputs of the pulse counter at the end of the pulse developed at - the output of the photoelectric transducing means, the outputs of the storage devices being connected via a digital-analogue converter to the input of the control means.
When such a regulating apparatus is used, a variation in the sliver movement speed caused by a change in the rotational speed of the driving means is accompanied by a proportional variation in the rotational speed of the disc and thus in the duration of pulses developed at the output of the photoelectric transducing means, as well as in the time period between the application to the counter of a train of pulses the number of which depends on the linear density and the application of signals from the counter outputs to the control means. As a result, said time period varies according to variation in the time required for movement of the sliver from the sensing means to the drafting zone whereby a high control accuracy is provided irrespective of the sliver movement speed.The development of the control signal in the proposed regulating apparatus is carried out by processing pulse signals with the aid of digital circuits, which ensures good noise-proof properties of the regulating apparatus and thus reliable operation thereof.
According to one embodiment of the invention the pulse train forming means comprises a pulsewidth modulator connected to the sensing means for developing pulses having width varying according to variation of the sliver linear density, the repetition period of said pulses being much smaller than the duration of the pulses developed at the output of the photoelectric transducing means, a pulse generator for developing pulses
having repetition frequency much greater than the
repetition frequency of the pulses developed by the pulse-width modulator, an AND circuit having its one input connected to the output of the pulse generator and its output connected to the counting input of the pulse counter, and a first pulse separating circuit having its one input connected to the output of the pulse-width
modulator, the other input of the first pulse
separating circuit being the synchronizing input of
the pulse train forming means and the output of the first pulse separating circuit being connected to another input of the AND circuit for applying to
the input of the AND circuit the first pulse the
leading edge of which is applied to the input of
the first pulse separating circuit from the output
of the pulse-width modulator during application of a pulse from the output of the photoelectric
transducing means to the other input of the first
pulse separating circuit.
It is expedient in this case that the pulse-width
modulator comprise a differential amplifier, a
resistor connected across the inverting input of
the differential amplifier, another resistor
connected across the non-inverting input of the
differential amplifier, and a capacitor connected
between the non-inverting input and the output of
the differential amplifier, and that the sensing
means comprise a radiation source position on one side of the sliver and a photosensitive device capable of changing its conductance in proportion to the intensity of the radiation incident thereupon, positioned in the path of the beam produced by said radiation source and connected between the inverting input and the output of the differential amplifier.
The pulse-width modulator and the sensing means so designed provide a linear relationship between the variations of the sliver linear density and of the signal at the output of the control means and thus ensure a higher control accuracy.
According to another embodiment of the invention the pulse train forming means comprises a monostable multivibrator, the input of the monostable multivibrator being the synchronizing input of the pulse train forming means, for developing a pulse upon application to the input of the monostable multivibrator of a pulse from the output of the photoelectric transducing means, the duration of the pulse developed by the multivibrator being much smaller than the duration of the pulses developed at the output of the photoelectric transducing means, a pulse-frequency modulator connected to the sensing means for developing pulses having repetition period much smaller than the duration of the pulses developed by the monostable multivibrator and repetition frequency varying according to variation of the sliver linear density, and an AND circuit having its one input connected to the output of the monostable multivibrator, its other input connected to the output of the pulse-width modulator and its output connected to the counting input of the pulse counter.
It is expedient that the delay means comprise a second disc having transparent and opaque areas alternately disposed along the circumference of the disc and being positioned between the radiation source and the photoelectric transducing means, and that both discs be coaxially mounted on a common shaft and adapted to be secured in different positions relative to each other. In that case the transparent and opaque areas of the discs should be positioned so as to provide variation in the overlaps of the transparent areas of one disc and the opaque areas of the other disc for adjusting the duration of the pulses developed at the output of the photoelectric transducing means according to the angular position of one disc relative to the other.
This allows, by adjusting the relative angular position of the discs, to attain such an overlap of their transparent and opaque areas which provides a maximum agreement between the duration of the pulse at the output of the photoelectric transducing means and the time required for movement of the sliver from the sensing means to the drafting zone. As a result, the proper adjustment of the regulating apparatus-is simplified.
The invention is further explained by a detailed description of its preferred embodiments with reference to the accompanying drawings, in which:
Fig. 1 shows a block-diagram of a regulating apparatus for automatically controlling the evenness of the linear density of a sliver, according to the invention;
Fig. 2 shows a possible configuration of the disc kinematically coupled to the sliver driving means;
Fig. 3 shows another possible configuration of the disc;
Fig. 4 shows two discs kinematically coupled to the sliver driving means and adapted to be secured in different positions relative to each other;
Fig. 5 shows possible configuraiions of the discs shown in Fig. 4;
Fig. 6 is a schematic representation of a pulsewidth modulator according to one of the embodiments of the invention;;
Fig. 7 is a block-diagram showing a portion of a regulating apparatus designed according to another embodiment of the invention;
Fig. 8 (a-e) shows signal waveforms obtained at various positions in the circuits shown in Fig. 1;
Fig. 9 (and) shows signal waveforms obtained at various positions in the circuit shown in Fig. 7.
Referring to Fig. 1 , the regulating apparatus for automatically controlling the evenness of the linear density of a sliver comprises a sensing means 1 responsive to the sliver linear density and including a radiation source 2, such as a lightemitting diode, and a photosensitive device 3 positioned on the different sides of the sliver 4.
The sensing means 1 is positioned ahead of the drafting assembly of a carding, combing or drawing textile machine (not shown). The sliver 4 passes through the drafting assembly, which comprises feed rollers 5 and delivery rollers 6. The sliver 4 is moved by a driving motor 7 of the textile machine.
The regulating apparatus further comprises a control means 8 for adjusting the rotational speed of the delivery rollers 6 and consisting of an auxiliary motor 9, an auxiliary motor control means 10 and differential mechanism 11 through which the delivery rollers 6 are coupled to the motors 7 and 9. The input of the auxiliary motor.
control means 10 is the input of the control means 8. The feed rollers 5 are directly coupled the motor 7.
The regulating apparatus further comprises another radiation source, which is a light source
12, a photoelectric transducing means 13 and a rotatable disc 14. The photoelectric transducing means 1 3 comprises a photosensitive device 15, an amplifier 1 6 and a flip-flop 1 7. The disc 14 is positioned between the light source 12 and the photosensitive device 1 5 and is kinematicaily coupled to the motor 7, e.g. is mounted on its shaft. The output of the flip-flop 1 7 is the output of the photoelectric transducing means 13.
The regulating apparatus further comprises a pulse train forming means 1 8 including a pulsewidth modulator 1 9 connected to the photosensitive device 3, a first pulse separating circuit 20 having its one input 21 connected to the output of the pulse-width modulator 19, the other input 22 of the first pulse separating circuit 20 being the synchronizing input of the pulse train forming means 1 8 and connected to the output of the flip-flop 17, a pulse generator 23, and an AND circuit 24 having its one input connected to the output of the first pulse separating circuit 20 and its other input connected to the output of the generator 23, the output of the AND circuit 24 being the output of the pulse train forming means 1 8. The first pulse separating circuit 20 is adapted to pass the first pulse the leading edge of which appears at its input 21 during application of a pulse to its input 22. The first pulse separating circuit 20 may be composed of a number of interconnected R-S flip-flops.
The regulating apparatus further comprises a pulse counter 25 having its counting input 26 connected to the output of the AND circuit 24; a reset means for resetting the counter 25, said reset means being a differentiating circuit 27 connected between the reset input 28 of the counter 25 and the output of the flip-flop 17, and a plurality of controlled storage devices equal in number to the bit position outputs of the counter 25. The controlled storage devices are D flip-flops 29, the D inputs 30 of the D flip-flops 29 being the information inputs of the storage devices, while the clock inputs 31 of the flip-flops 29 are the control inputs of the storage devices. The D inputs 30 of the D flip-flops 29 are respectively connected to the corresponding bit position outputs of the counter 25.The clock inputs 31 of the D flip-flops 29 are connected to the output of the flip-flop 17 via a NOT circuit 32 and a differentiating circuit 33 connected in series. The outputs of the D flip-flops 29 are connected to the input of the auxiliary motor control means 10 via a digital-to-analogue converter 34.
Fig. 2 shows one of possible configurations of the disc 14. Referring to Fig. 2, the disc 14 has apertures 35 arranged in pairs along the circumference of the disc 14. Angular distances a between the apertures of each pair are equal to each other, the angular dimensions of the apertures 35 themselves being small in comparison with the angular distances a. The apertures 35 are arranged at such a distance from the axis of the disc 14 that they cross the path of the light beam falling from the source 12 (Fig. 1) on the photosensitive device 1 5 during rotation of the disc 1 4.
Fig. 3 shows another possible configuration of the disc 14. Referring to Fig. 3, the disc 14 has apertures 36 equally spaced along its circumference, the angular dimensions of the apertures 36 being equal to each other. The apertures 36 are arranged at such a distance from the axis of the disc 1 4 that they cross the path of the light beam falling from the soruce 12 on the photosensitive device 1 5 during rotation of the disc 14. In this case the flip-flop 17 in the photoelectric transducing means 1 3 is not needed, and the input 22 of the first pulse separating circuit 20. the input of the differentiating circuit 27 and the inputs 31 of the
D flip-flops 29 are connected to the output of the amplifier 16 directly or via a pulse shaper (not shown).
According to another embodiment of the invention shown in Figs. 4 and 5 the regulating apparatus comprises a second disc 37 (Fig. 4) mounted coaxially with the disc 14 on a common shaft 38 kinematically coupled to the motor 7 (Fig. 1), e.g. on the shaft of the motor 7. To secure the discs 14 and 37 (Fig. 4) relative to each other there are provided nuts 39 and 40 respectively mounted on the shaft 38 on the sides of the discs 14 and 37.
Referring to Fig. 5, the discs 14 and 37 shown in Fig. 4 have apertures 41 and 42 (Fig. 5), respectively, arranged similarly to the arrangement of the apertures 24 shown in Fig. 3 and at the same distance from the axis of the discs 14 and 37 (Fig. 4) so that, upon a corresponding angular displacement of the discs, the apertures 41 and 42 (Fig. 5) may overlap by an angle y. In this case the flip-flop 1 7 (Fig. 1) also is not used and the input 22 of the first pulse separating circuit 20, the input of the differentiating circuit 27 and the inputs 31 of the
D flip-flops 29 are connected to the output of the amplifier 16 in the same way as in the case of the disc 14 having configuration shown in Fig. 3.
Fig. 6 shows a circuit diagram of the pulsewidth modulator 19 according to one of the embodiments of the invention. Referring to Fig. 6, the pulse-width modulator 1 9 comprises a differential amplifier 43 having an inverting input 44 and a non-inverting input 45, a resistor 46 connected across the inverting 44 of the amplifier 43, a resistor 47 connected across the noninverting input 45 of the amplifier 43, and a capacitor 48 connected between the noninverting input 45 and the output of the amplifier 43. The photosensitive device 3 of the sensing means 1 is a photoresistor connected between the input 44 and the output of the amplifier 43.
The output of the amplifier 43 is the output of the pulse-width modulator 1 9 and is connected to the input 21 of the first pulse separating circuit 20.
Fig. 7 shows a circuit diagram of the pulse train forming means 18 according to still another embodiment of the invention. Referring to Fig. 7, the pulse train forming means 18 comprises a pulse-frequency modulator 49, a monostable multivibrator 50 and an AND circuit 51. The pulse-frequency modulator 49 is connected to the photosensitive device 3 of the sensing means 1, the input of the monostable multivibrator 50 being connected to the output of the photoelectric transducing means 13, while the inputs of the AND circuit 51 are respectively connected to the outputs of the pulse-frequency modulator 49 and of the monostable multivibrator 50. The output of the AND circuit 51 is connected to the counting input 26 of the counter 25.The pulse-frequency modulator 49 may be, for
example, an astable multivibrator, while the
photosensitive device 3 may be a photoresistor
connected into one of the multivibrator circuits
which determine the period of the multivibrator
output voltage.
The regulating apparatus operates as follows.
During operation of the textile machine the
sliver 4 (Fig. 1) moves as shown by the arrow. The
sliver 4 enters the drafting assembly through the
feed rollers 5 driven by the motor 7 and leaves the
drafting assembly through the delivery rollers 6.
Radiation from the radiation source 2 of the
sensing means 1 passes through the sliver 4 and
falls on the photosensitive device 3 bringing
about a change in the duration of the pulses at the
output of the pulse-width modulator 19 in
accordance with the sliver linear density.
If the pulse-width modulator 1 9 is made as
shown in Fig. 6, the development of the signal at
the output of the pulse-width modulator 19 is
accomplished in the following way.
According to the Lambert law, the intensity of
the radiation which has passed through a
material uniformly dissipating this radiation,
such as the sliver 4, varies as a function
of the thickness and of the radiation absorption
factor of the material in conformity with the
exponential law.
The linear density of a fibrous material, such as
the sliver 4, i.e. the weight of the material per unit
of length, is proportional to the thickness of the
material and to the number of the fibres
constituting the material per unit of thickness. The
absorption factor of a fibrous material is
proportional to the number of the fibres per unit of
thickness. Consequently, the intensity of the
radiation which has passed through the sliver 4
varies as a function of the linear density of the
sliver 4 in conformity with the exponential law.
As is well known, a circuit comprising a
differential amplifier, a capacitor connected
between the non-inverting input and the output of
the amplifier, and resistors of which two are
connected across the inputs of the amplifier and
the third is connected between the inverting input
and the output of the amplifier, is a relaxation
oscillator wherein a train of bidirectional
rectangular pulses is developed at the output of
the amplifier, the repetition period of the pulses
being defined by the expression:
2R2 T=2R1Cln ( I+ R3
where T is the repetition period of the pulses at
the output of the amplifier.
R, is the resistance of the. resistor connected
across the non-inverting input of the
amplifier,
C is the capacitance of the capacitor connected
between the non-inverting input and the
output of the amplifier, R2 is the resistance of the resistor connected
between the inverting input and the output
of the amplifier,
R3 is the resistance of the resistor connected
across the inverting input of the amplifier (see, for example, Gutnikov V. L. "Primenenie operatsionnykh usilitelei v izmeritelnoi tekhnike",
Leningrad, 1975, p. 98).
If the resistance of the resistor R3 connected across the inverting input of the amplifier is much smaller than the resistance of the resistor R2 connected between the inverting input and the output of the output of the amplifier, it can be assumed that theArepetition period of the pulses at the output of the amplifier is proportional to the logarithm of the resistance of the resistor connected between the inverting input and the output of the amplifier.
In the circuit shown in Fig. 6 the resistances of the resistors 47 and 46 respectively represent the resistance Rl and R3,the resistance of the photosensitive device 3 represents the resistance
R2, and the capacitance of the capacitor 48 represents the capacitance C.
As is well known, the current-illumination characteristics of a photoresistor has a substantial linear portion within which the current flowing through the photoresistor at a constant voltage thereacross varies in proportion to the intensity of the radiation incident upon the photoresistor.
Therefore, if the photosensitive device 3 is a photoresistor and the source 2 is properly chosen, a linear relationship will be provided between the intensity of the radiation incident upon the photosensitive device 3 and the conductance of the latter in a large range of a sliver linear densities. With the resistor 46 being chosen so that its resistance is much smaller than the minimum value of the resistance of the photosensitive device 3, i.e. of the photoresistor, it can be assumed that the repetition period of the pulses at the output of the amplifier 43 is proportional to the logarithm of the conductance of the photosensitive device 3 and hence, to the logarithm of the radiation incident thereupon.As pointed out above, the intensity of the radiation which has passed through the sliver 4 varies as a function of its linear density in conformity with the exponential law. Consequently, the repetition period of the pulses at the output of the amplifier 43, and hence the duration of said pulses, varies in proportion to the linear density of the sliver 4* To provide a linear relationship between the sliver linear density and the duration of the pulses at the output of the amplifier 43 other photosensitive devices having their conductance varying in proportion to the intensity of the radiation incident thereupon may be used, such as photodiodes. As is well known, the reverse conductance of a photodiode varies in proportion to the intensity of the radiation incident thereupon in a wide range of said intensities.If the photosensitive device 3 is a photodiode, the duration of the pulses of one polarity at the output of the amplifier 43 will be determined by the forward resistance of the photodiode, which is very small so that the duration of said pulses will be also small, whereas the duration of the pulses of the other polarity will vary in proportion to the logarithm of the reverse resistance (and hence, of the reverse conductance) of the photodiode, i.e. in proportion to the linear density of the sliver 4. The polarity of the pulses having variable duration will depend on the direction in which the photodiode is connected.To produce positive pulses at the output of the amplifier 43 having their duration proportional to the sliver linear density the photodiode should be connected so that its cathode is connected to the output of the amplifier 43 and its anode is connected to the inverting input 44 of the amplifier 43.
The pulse train produced at the output of the pulse-width modulator 19 is shown in Fig. 8a.
In the course of operation the motor 7 rotates the disc 1 4 the rotation of which is thus synchronized with the movement of the sliver 4 through the drafting assembly. During rotation of the disc 14 the light beam from the source 12 falls periodically through the apertures in the disc 14 on the photosensitive device 1 5 of the photoelectric transducing means 13.
If the disc 14 has apertures 35 disposed as shown in Fig. 2, the passage of the light beam through each pair of the apertures 35 causes the photosensitive device 1 5 (Fig. I) to develop a pair of pulses which via the amplifier 16 are applied to the input of the flip-flop 17, the first pulse of each pair setting the flip-flop 1 7 to a state at which it develops voltage at its output, while the second pulse of the same pair resets the flip-flop 1 7. As a result of this a rectangular pulse appears at the output of the photoelectric transducing means 13, the duration of the pulse being dependent on the rotational speed of the disc 14 and on the angular distance a between the apertures 35 (Fig.
2).
If the disc 1 4 has the configuration shown in
Fig. 3, the passage of the light beam from the source 12 (Fig. 1) through any of the apertures 36 (Fig. 3) causes a rectangular pulse to appear at the output of the amplifier 1 6 (Fig. 1). The duration of the pulse at the output of the photoelectric transducing means 1 3 depends in this case on the rotational speed of the disc 14 and on the angular dimensions p of the apertures 36 (Fig. 3).
If the regulating device comprises two discs 14 and 37 (Figs. 4 and 5), the duration of the pulses developed at the output of the photoelectric transducing means 13 (Fig. 1) as a result of rotation of the discs 14 and 37 (Fig. 4) depends on the rotational speed of the discs 14 and 37 and on the angular dimensions y of the overlap of the apertures 41 and 42 (Fig. 5).
The pulse developed at the output of the photoelectric transducing means 1 3 (Fig. 1) is shown in Fig. 8b.
This pulse is applied to the input 22 of the first pulse separating circuit 20 (Fig. 1), whose other input 21 is supplied with a pulse train from the pulse-width modulator 19. The first of the pulses produced by the pulse-width modulator 1 9 the leading edge of which arrives at the input 21 of the circuit 20 after the arrival of the leading edge of the pulse from the output of the photoelectric transducing means 13 at the input 22 appears at the output of the circuit 20.The repetition period of the pulses developed by the pulse-width modulator 19 is much smaller than the duration of the pulses developed at the output of the photoelectric transducing means 13 so that the instant of termination of the pulse at the output of the circuit 20 is close to the instant at which the leading edge of the pulse from the photoelectric transducing means 13 appears at the input 22 of the circuit 20. The pulse developed at the output of the circuit 20 is shown in Fig. 8c.
The pulse from the output of the circuit 20 (Fig. 1) is applied to one of the inputs of the AND circuit 24 whose other input is supplied with a train of high-frequency pulses produced by the generator 23 and shown in Fig. Sd. As a result, a pulse train appears at the output of the AND circuit 24 (Fig. 1), the number of the pulses in said pulse train corresponding to the duration of the pulse separated by the circuit 20 and thus varying in accordance with variation of the linear density of the sliver 4.If the pulse-width modulator 19 is made as shown in Fig. 6 and the photosensitive device 3 is made so that its conductance is a
linear function of the intensity of the radiation
incident thereupon, the number of the pulses at the output of the circuit 20 is proportional to the linear density of the sliver 4.
The pulse train from the output of the AND circuit 24 (Fig. 1) is applied to the counting input 26 of the counter 25. This pulse train is shown in Fig. Se.
The counter 25 (Fig. 1) develops at its bit position outputs a binary code corresponding to the number of the pulses applied to the input 26.
The signal from the bit position outputs of the counter 25 are applied to the inputs 30 of the D flip-flops 29. However, the signals at the outputs of the counter 25 have no effect on the D flipflops 29 until their clock inputs 31 are supplied with a clock pulse. At the instant of termination of the pulse at the output of the photoelectric transducing means 13 the voltage at the output of the NOT circuit 32 leaps to a positive level producing a pulse at the output of the differential circuit 33, which is applied to the clock inputs 31 of the D flip-flops 29. As a result, the binary code from the bit position outputs of the counter 25 is stored to the D flip-flops 29 and is delivered from their outputs to the digital-to-analogue converter 34 which converts said binary code to an analogue signal furnished to the auxiliary motor control means 10.
The appearance at the differentiating circuit 27 of the leading edge of the next pulse produced at the output of the photoelectric transducing means 1 3 causes the differentiating circuit 27 to develop a pulse at its output. This pulse is supplied to the reset input 28 of the counter 25 resetting the latter. As this takes place, no change in the states of the D flip-flops 29 occurs.Thereupon the counter 25 again commences counting the pulses delivered to its counting input 26 from the output of the AND circuit 24, as was described above, with the result that the counter 25 develops at its output a binary code corresponding to the density of the portion of the sliver 4 passing through the sensing means 1 at the instant directly following the application of the leading edge of a pulse from the photoelectric transducing means 13 to the input 22 of the first pulse separating circuit 20.
The signal which corresponds to the sliver linear density at said instant will be furnished to the auxiliary motor control means 10 at the time of termination of the pulse at the output of the photoelectric transducing means 13. If the pulsewidth modulator 1 9 shown in Fig. 6 is used and the conductance of the photosensitive device 3 is a linear function of the intensity of the radiation incident thereupon, the signal at the input of the control means 10 will be proportional to the linear density of the sliver 4.
The control means 10 (Fig. 1) with the aid of the differential mechanism 11 alters the rotational speed of the delivery rollers 6 of the drafting assembly in accordance with the deviation of the signal at the output of the converter 34 from a value corresponding to the required linear density of the sliver 4. A reference signal corresponding to the required linear density may be fed to different points of the regulating apparatus, e.g. to the sensing means 1 , to the train pulse forming means 18, to the pulse counter 25 or to the control means 8.
Thus, in the course of operation of the regulating apparatus the instant of altering the speed of the delivery rollers 6 is delayed in relation to the instant of measurement of the linear density for a time period depending on the duration of the pulse produced at the output of the photoelectric transducing means 13. The duration of said pulse should be such as to provide variation of the speed of the delivery rollers 6 with a time delay which is equal to the time period required for movement of the sliver 4 from the sensing means 1 to the drafting zone located between the rollers 5 and 6. Therefore, the choice of the pulse duration depends on the location of the drafting zone which is determined mostly by the length of the fibers constituting the sliver 4.
Besides, in choosing the pulse duration account must be taken of the time lag caused by the inertial properties of different parts of the regulating apparatus, mainly of the control means 8.
As pointed out above, the duration of the pulse at the output of the photoelectric transducing means 13 depends on the rotational speed of the disc 14 and on the angular distance a between the apertures 35 if the disc 14 has the configuration shown in Fig. 2, on the angular dimensions p of the apertures 36 if the disc 14 has the configuration shown in Fig. 3, and on the angular dimensions y of the overlap of the apertures 41 and 42 if the two discs 14 and 37 having configurations shown in Fig. 5 and mounted as shown in Fig. 4 are used.The values of the angles a, p and y may be determined by calculations or experimentally, e.g. by obtaining oscillograms of the sliver linear density at the output of drafting assembly under different angle values and by determining the value ensuring a minimum unevenness of the sliver 4. If two discs 1 4 and 37 (Fig. 4) are used, the correct choice of the angle value is simplified and may be achieved by securing the discs 14 and 37 with the aid of the nuts 39 and 40 in different positions relative to each other corresponding to different of the angular dimension y (Fig. 5) and by finding a relative position of the discs ensuring a minimum unevenness of the sliver 4.
If the pulse train forming means 18 comprises the pulse-frequency modulator 49 as shown in
Fig. 7, the modulator 49 develops at its outputs train of pulses having a repetition frequency varying according to variation of the sliver linear density. The output signal of the pulse-frequency modulator 49 is shown in Fig. 9a. The signal at the output of the photoelectric transducing means 1 3 (Fig. 1), which is shown in Fig. 9b, is applied to the input of the monostable multivibrator 43 (Fig.
1) and by its leading edge causes the multivibrator 49 to develop at its output a pulse of a predetermined duration as shown in Fig. 9c. The parameters of the multivibrator 50 are chosen so that the duration of its output pulse is small in comparison to the duration of the pulse produced at the output of the photoelectric transducing means 1 3 and is large in comparison to the repetition period of the pulses at the output of the pulse-frequency modulator 49.Pulses from the outputs of the pulse-frequency modulator 49 and the multivibrator 50 are fed to the inputs of the
AND circuit 51 whereby a pulse train is developed at the output of the latter, the number of the pulses in said pulse train being dependent on the repetition frequency of the pulses at the output of the pulse-frequency modulator 49, and thus varying according to variation of the sliver linear density. The pulse train from the output of the
AND circuit 51 is applied to the input 26 of the pulse counter 25. Said pulse train is shown in Fig.
9d.
The rest of operation of the regulating apparatus comprising the pulse-frequency modulator 49 does not differ from the operation of the regulating apparatus shown in Fig. 1.
Thus the proposed regulating apparatus
ensures a delay in application of a signal from the
output of the counter 25 to the control means 8 in
relation to the tine of measurement of the sliver
linear density for a time period equal to that
required for movement of the sliver 4 from the
sensing means 1 to the drafting zone.When a
change in the movement speed of the sliver 4
occurs, it automatically brings about a
proportional change in the duration of the pulse at
the output of the photoelectric transducing means
13 so that the time period between the time of
measurement of the sliver linear density and the
time of application of a corresponding signal to the control means 8 always approximately equals the time period required for movement of the sliver 4 from the sensing means 1 to the drafting zone and is practically independent of the rotational speed of the motor of the textile machine.
While the present invention was described herein with the discs 14 and 37 having configurations shown in Figs. 2-5, it will be understood that other discs having transparent and opaque areas alternately disposed along the circumferences of the discs may be used provided that the angular dimensions and the positioning of the transparent areas ensure the development of the pulses at the output of the photoelectric means 13 (Fig. 1) at the required time periods as described above. The transparent areas of the discs may be formed, for example, by radial cutouts. It is also possible to make the regulating apparatus so that the time period between the application of pulses of the counting input 26 of the counter 25 and the application of clock pulses to the D flip-flops 29 will be determined by the angular dimensions of the opaque areas of the discs 14 and 37 (Figs. 2-5).
Claims (7)
1. A regulating apparatus for automatically controlling the evenness of the linear density of a sliver by means of a drafting assembly, comprising a sensing means responsive to the linear density of the sliver and positioned ahead of the feed rollers of the drafting assembly, a control means for adjusting the rotational speed of the delivery rollers of the drafting assembly, and a delay means connected between the sensing means and the control means, wherein the delay means comprises a radiation source, a photoelectric transducing means positioned in the path of the beam produced by the radiation source, a disc rotatably positioned between the radiation source and the photoelectric transducing means and kinematically coupled to the sliver driving means,
Said disc having transparent and opaque areas alternately disposed along the circumference of the disc for developing at the output of the photoelectric transducing means a sequence of pulses, the duration of the pulses varying according to variation of the movement speed of the sliver, a pulse train forming means having a synchronizing input connected to the output of the photoelectric transducing means for developing a pulse train having a limited number of pulses upon application of a pulse from the output of the photoelectric transducing means to the synchronizing input of the pulse train forming means the repetition period of the pulse in said pulse train being much smaller than the duration of the pulses at the output of the photoelectric transducing means, and connected to the sensing means for varying the number of pulses in the developed pulse trains according to the linear density of the sliver, a pulse counter having its counting input connected to the output of the pulse train forming means, a reset means synchronized with the pulse train forming means and connected to the reset input of the pulse counter for resetting the pulse counter before the pulse train developed by the pulse train forming means is applied to the counting input of the pulse counter, a plurality of controlled storage devices respectively connected to the bit position outputs of the pulse counter and having their control inputs connected to the output of the photoelectric transducing means for storing information from the corresponding bit position outputs of the pulse counter at the end of the pulse developed at the output of the photoelectric transducing means, the outputs of the storage devices being connected via a digital-to-analogue converter to the input of the control means.
2. A regulating apparatus according to Claim ), wherein the pulse train forming means comprises a pulse-width modulator connected to the sensing means for developing pulses having width varying according to variation of the sliver linear density, the repetition period of said pulses being much smaller than the duration of the pulses developed at the output of the photoelectric transducing means, a pulse generator for developing pulses having repetition frequency much greater than the repetition frequency of the pulses developed by the pulse-width modulator, an AND circuit having its one input connected to the output of the pulse generator and its output connected to the counting input of the pulse counter, and a first pulse separating circuit having its one input connected to the output of the pulse-width modulator, the other input of the first pulse separating circuit being the synchronizing input of the pulse train forming means and the output of the first pulse separating circuit being connected to another input of the AND circuit for applying to the input of the AND circuit the first pulse the leading edge of which is applied to the input of the first pulse separating circuit from the output of the pulse-width modulator during application of a pulse from the output of the photoelectric transducing means to the other input of the first separating circuit.
3. A regulating apparatus according to Claim 2, wherein the pulse-width modulator comprises a differential amplifier, a resistor connected across the inverting input of the differential amplifier, another resistor connected across the noninverting input of the differential amplifier and a capacitor connected between the non-inverting input and the output of the differential amplifier, and the sensing means includes a radiation source positioned on one side of the sliver and a photosensitive device capable of changing its conductance in proportion to the intensity of the radiation incident thereupon, said photosensitive device being positioned on the other side of the sliver in the path of the beam produced by said radiation source and connected between the inverting input and the output of the differential amplifier.
4. A regulating apparatus according to Claim 1, wherein the pulse train forming means comprises a monostable multivibrator, the input of the monostable multivibrator being the synchronizing input of the pulse train forming means, for developing a pulse upon application to the input of the monostable multivibrator of a pulse from the output of the photoelectric transducing means, the duration of the pulse developed by the multivibrator being much smaller than the duration of the pulses developed at the output of the photoelectric transducing means, a pulsefrequency modulator connected to the sensing means for developing pulses having repetition period much smaller than the duration of the pulses developed by the monostable multivibrator and repetition frequency varying according to variation of the sliver linear density, and an AND circuit having its one input connected to the output of the monostable multivibrator, its other input connected to the output of the pulsefrequency modulator and its output connected to the counting input of the pulse counter.
5. A regulating apparatus according to any one of the Claims 1 4, wherein the delay means further comprises a second disc having transparent and opaque areas alternately disposed along the circumference of the disc and being positioned between the photoelectric transducing means and the radiation source producing the beam in the path of which the photoelectric transducing means is positioned, both discs being coaxially mounted on a common shaft and adapted to be secured in different angular positions relative to each other, the transparent and opaque areas of the discs being positioned so as to provide variation in the overlap of the transparent areas of one disc and the opaque areas of the other disc for adjusting the duration of the pulses developed at the outupt of the photoelectric transducing means according to the angular position of one disc relative to the other disc.
6. A regulating apparatus for automatically controlling the evenness of the linear density of a sliver substantially as hereinabove described with references to and as shown in the accompanying drawings.
7. Apparatus for controlling the linear density of an elongate fibrous material being continuoeusly processed through a drafting assembly comprising spaced apart feed and delivery means, said apparatus including: sensing means, located upstream of said feed means, responsive to the linear density of the fibrous material for producing a first signal representative thereof; control means responsive to said first signal for adjusting the speed of the delivery means to compensate for any deviations in the linear density of the material; means responsive to the speed of the feed means for producing a second signal representative thereof; and means responsive to said second signal for delaying the response of said control means to said first signal for a period commensurate with the time required for the material to be transported from the location of said sensing means into the drafting zone irrespective of the rate of feed of the material.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB8026266A GB2081758B (en) | 1980-08-12 | 1980-08-12 | Regulating apparatus for automatically controlling the evenness of the linear density of a silver |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB8026266A GB2081758B (en) | 1980-08-12 | 1980-08-12 | Regulating apparatus for automatically controlling the evenness of the linear density of a silver |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB2081758A true GB2081758A (en) | 1982-02-24 |
| GB2081758B GB2081758B (en) | 1984-02-22 |
Family
ID=10515404
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB8026266A Expired GB2081758B (en) | 1980-08-12 | 1980-08-12 | Regulating apparatus for automatically controlling the evenness of the linear density of a silver |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB2081758B (en) |
Cited By (13)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0141505A1 (en) * | 1983-09-05 | 1985-05-15 | Chubu Seiko Co. Ltd. | Device for automatically controlling the draft in a spinning machine |
| EP0176661A2 (en) * | 1984-09-25 | 1986-04-09 | Zellweger Luwa Ag | Method and apparatus for optimum drafting in regulating draft frames of the textile industry |
| US4753665A (en) * | 1985-08-23 | 1988-06-28 | James Fahey | Method and apparatus for controlling the suction pressure in a dust collecting duct |
| US4974296A (en) * | 1990-02-23 | 1990-12-04 | Platt Saco Lowell Corporation, Inc. | Apparatus for correcting irregularities in a textile strand |
| US5005262A (en) * | 1988-09-21 | 1991-04-09 | Rieter Machine Works, Ltd. | Comber with electric motor driven intermittent feed roller |
| US5134755A (en) * | 1989-08-11 | 1992-08-04 | Maschinenfabrik Rieter Ag | Method and apparatus for controlling a drafting unit |
| US5152033A (en) * | 1991-07-15 | 1992-10-06 | Myrick-White, Inc. | Textile apparatus/method for reducing variations in silver weight |
| US5230125A (en) * | 1988-12-22 | 1993-07-27 | Rieter Machine Works, Ltd. | Combing machine and process for forming an even combed sliver |
| EP0615181A1 (en) * | 1993-03-12 | 1994-09-14 | Rieter Ingolstadt Spinnereimaschinenbau AG | Method and device for automatically adjusting the speed ratios of a drafting machine |
| US5394591A (en) * | 1990-09-26 | 1995-03-07 | Maschinenfabrik Rieter Ag | Autoleveller drafting arrangement with mass fluctuation control |
| US5490308A (en) * | 1990-06-19 | 1996-02-13 | Hoechst Aktiengesellschaft | Monitoring the uniformity of tows |
| US5509179A (en) * | 1990-06-25 | 1996-04-23 | Mondini; Giancarlo | Autoleveller draw frame having process feed back control system |
| US5815889A (en) * | 1994-07-12 | 1998-10-06 | Csm-Saechsische Spinnereimaschinen Gmbh | Process and device for regulating drafting equipment, in particular in carding machines |
-
1980
- 1980-08-12 GB GB8026266A patent/GB2081758B/en not_active Expired
Cited By (17)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0141505A1 (en) * | 1983-09-05 | 1985-05-15 | Chubu Seiko Co. Ltd. | Device for automatically controlling the draft in a spinning machine |
| US4703431A (en) * | 1983-09-05 | 1987-10-27 | Chuba Seiko Co., Ltd. | Sliver drawing apparatus |
| EP0176661A2 (en) * | 1984-09-25 | 1986-04-09 | Zellweger Luwa Ag | Method and apparatus for optimum drafting in regulating draft frames of the textile industry |
| EP0176661A3 (en) * | 1984-09-25 | 1990-07-04 | Zellweger Uster Ag | Method and apparatus for optimum drafting in regulating draft frames of the textile industry |
| US4753665A (en) * | 1985-08-23 | 1988-06-28 | James Fahey | Method and apparatus for controlling the suction pressure in a dust collecting duct |
| US4820317A (en) * | 1985-08-23 | 1989-04-11 | James Fahey | Method and apparatus for controlling the suction pressure in a dust collecting duct |
| US5005262A (en) * | 1988-09-21 | 1991-04-09 | Rieter Machine Works, Ltd. | Comber with electric motor driven intermittent feed roller |
| US5230125A (en) * | 1988-12-22 | 1993-07-27 | Rieter Machine Works, Ltd. | Combing machine and process for forming an even combed sliver |
| US5134755A (en) * | 1989-08-11 | 1992-08-04 | Maschinenfabrik Rieter Ag | Method and apparatus for controlling a drafting unit |
| US4974296A (en) * | 1990-02-23 | 1990-12-04 | Platt Saco Lowell Corporation, Inc. | Apparatus for correcting irregularities in a textile strand |
| US5490308A (en) * | 1990-06-19 | 1996-02-13 | Hoechst Aktiengesellschaft | Monitoring the uniformity of tows |
| US5509179A (en) * | 1990-06-25 | 1996-04-23 | Mondini; Giancarlo | Autoleveller draw frame having process feed back control system |
| US5394591A (en) * | 1990-09-26 | 1995-03-07 | Maschinenfabrik Rieter Ag | Autoleveller drafting arrangement with mass fluctuation control |
| US5152033A (en) * | 1991-07-15 | 1992-10-06 | Myrick-White, Inc. | Textile apparatus/method for reducing variations in silver weight |
| EP0615181A1 (en) * | 1993-03-12 | 1994-09-14 | Rieter Ingolstadt Spinnereimaschinenbau AG | Method and device for automatically adjusting the speed ratios of a drafting machine |
| US5452626A (en) * | 1993-03-12 | 1995-09-26 | Rieter Ingolstadt Spinnereimaschinenbau Ag | Process and device for the automatic adjustment of rotational speed ratios between operating elements of a draw frame |
| US5815889A (en) * | 1994-07-12 | 1998-10-06 | Csm-Saechsische Spinnereimaschinen Gmbh | Process and device for regulating drafting equipment, in particular in carding machines |
Also Published As
| Publication number | Publication date |
|---|---|
| GB2081758B (en) | 1984-02-22 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PCNP | Patent ceased through non-payment of renewal fee |