US2887620A - Electronic control circuit useful in the manufacture of thick-and-thin yarn - Google Patents

Description

c. w. CROMWELL, JR 2,887,620 ELECTRONIC CONTROL CIRCUIT USEFUL IN THE May 19, 1959 MANUFACTURE OF THICK-AND-THIN YARN v 3 Sheets-Sheet i Filed April 26, 1955 INVENTOR ATTOREY May 19, 1959 T c. w. cRoMWELL, JR 2,887,620 C ELECTRONIC CONTROL CIRCUIT USEFUL 1N THE MANUFACTURE OF THICK-AND-THIN YARN 5 Sheets-Sheet 2 Filed April 26, 1955 um m WH (cf-Tjuuulllulu (Illlulllll INVENTOR ATTORNEY CHIP/WAL X44 WMWEL/ Jl?.

BY (Jo/Jim A INVENTOR 3 Sheets-Sheet 3 I I l CAR/14 WWW/2911 :sa MEQ/4x51@ O ATTORNEY May 19, 1959 c. w. cRoMwELL, JR

f ELECTRONIC CONTROL CIRCUIT USEFUL IN THE MANUFACTURE OF THICK-AND--THIN YARN Filed April 26, 1955 ELECTRONIC CONTROL CIRCUIT USEFUL IN THE MANUFACTURE F THICK-AND-THIN YARN Carroll W. Cromwell, Jr., Asheville, N.C., assignor to American Enka Corporation, Enka, N.C., a corporation of Delaware Application April 26, 1955, Serial No. 504,057 7 Claims. (Cl. 315-204) This invention relates to apparatus and methods for the spinning of viscose nub yarn, and more particularly, to an electronic control circuit for controlling the operation of the pump that feeds the spinnerets for such yarn.

Nub yarn is sometimes referred to as thick and thin yarn, and is characterized by a thin portion called the base denier which is followed by a relatively short thick portion. These thick portions are called the nubs and the Weight per unit length thereof generally exceeds that of the base denier by a substantial amount.

Accordingly, therefore, the primary object of this invention is to provide a new and novel electronic circuit for controlling the apparatus which is used in producing such thick and thin yarn.

Another object of this invention is to provide a circuit for creating electronic pulses to control the closure intervals of an electromagnetic clutch used in applying output torque from a high-speed drive to a spinneret pump.

Another object of this invention is to provide an electronic control system for production spinning of thick and thin yarn.

Still another object of this invention is to provide a system of electronically controlling the pump shaft speed of a yarn spinning machine.

As is `well known to those skilled in the art, viscose yarn is made by extruding the raw material from spinnerets into chemical baths which treat the extruded threads. The denier of these threads can be readily controlled by regulating the speed of operation of the spinneret pump. This pump feeds the viscose from its source of supply to the spinnerets, and is set at a certain speed to produce the base denier. I-f at any time it is desired to increase the denier, the pump' is accelerated. In this manner, the amount of material per unit time fed to the spinneret determines the denier. The means by which this pump control is obtained in accordance with the new and novel electronic control circuit of this invention is broadly as follows.

The pump has two drives, a low-speed drive and a high-speed drive. The low-speed drive operates the pump at the proper speed to produce the base denier, and, conversely the high-speed drive operates it at the proper speed to produce the nubs. If, for example, both drives control the pump alternately and for equal periods of time, a yarn having approximately equal thick and thin portions is produced. Each of the two drives is connected through a clutch to the pump shaft, the pump being of a conventional type such as a gear pump. The low-speed drive is connected to a break away or slip Y type clutch whose faces engage and provide drive to the shaft only when the shaft lspeed is below the speed of the low-speed drive. If the shaft speed is greater than the speed of the low-speed drive, this low-speed clutch slips to provide free-wheeling of the clutch. The shaft speed is greater than the speed of the low-speed drive when the electronic control circuit cuts in the high-speed drive. The high-speed drive is then operatively connected to the pump shaft through a suitable electromagnetic clutch AUnited States Patent 0 ICC whose faces engage, and therefore provide high-speed drive to the shaft when the electronic control so dictates.

The foregoing and other objects of the invention will be apparent from the following detailed description of the accompanying drawings, in which like numerals indicate like objects.

Figure 1 is a block diagram of apparatus utilizing the electronic control circuit of this invention and employing an electromagnetic clutch as the high-speed clutch;

Figure 2 illustrates a front view of the toothed wheel and roller-actuated microswitch utilized in energizing the control circuit of this invention;

Figure 3 illustrates a side view of the toothed wheel and shows the drive mechanism therefor;

Figure 4 illustrates a block diagram of the circuitry and components of the new and novel electronic control circuit of this invention; and

Figure 5 is a schematic wiring diagram of the circuit components of the electronic control circuit.

Referring now to the drawings, and more particularly to Figure 1, there is shown a yarn spinning apparatus which includes a low-speed drive 1, a low-speed clutch Z and a high-speed drive 3. The high-speed drive 3 is effectively separated by means of an electromagnetic clutch 4 from a spinneret gear pump 5. An electronic control circuit 10, to be explained in connection with Figure 5 hereinbelow, is provided with output terminals X and Y conductively connected to supply current to electromagnetic clutch 4 via the slip rings 6-6. While a modified Warner type electromagnetic clutch has been found particularly suitable in this application, it will be appreciated that the invention is by no means limited thereto and that any suitable type of electromagnetic clutch maybe energized by the electronic control circuit of this invention.

Continuing now with the detailed description of the diagram in Figure l, the spinneret pump 5 is operatively connected to the viscose supply unit 7, and receives a supply of viscose therefrom. The output of the spinneret pump is applied to the spinneret units, per se, as indicated diagrarnmatically at 8 on the drawing. In operation, the low-speed drive 2 will normally supply torque to the spinneret pump 5, via the low-speed clutch 2. As earlier stated in the specification, the clutch 2 shown in Figure l is of the break away type and cannot drive the spinneret pump during those intervals when it is rotated by the high-speed drive at an angular velocity greater than that of the low-speed drive.

Turning to Figure 2 and Figure 3 which illustrate the method and means for initiating the switching sequence of the control circuit of this invention, there is illustrated a Wheel 11 provided with a plurality of spaced teeth 12 aiixed to the periphery thereof. Wheel 11 is journalled for rotation on a base member 13, and is mounted to actuate a roller-actuated microswitch S1 when turned. The microswitch Slis bolted or otherwise securely axed to the frame 13, such that the spaced teeth 12 on the periphery of the wheel 11 will engage and deflect the roller member 14 and repetitively open and close the contacts of the microswitch. The application of the rolleractuated microswitch S1 to the control circuit will be developed more fully below.

In Figure 3 there is illustrated a side view of the device shown in Figure 2, showing the drive mechanism therefor. The wheel 11 is securely atiixed to an operating shaft 15 which is journalled in bearing 16. Between the shaft 15 and the electric drive motor 17 there is interposed a suitable speed reducer 18. It will be appreciated that while an exemplary structure for supplying torque `to the toothed wheel has been taught in accordance with the requirement of the patent statute, other suitable types of drive fall equally well within the purview of this invention and the claims thereto. Furthermore, it will also be appreciated that while the utilization of spaced peripheral teeth on a rotating wheel comprises a single eminently practical method and means for actuating the microswitch S1 of this invention, the invention is not strictly limited thereto. More particularly, other types of repetitive energization are suitable and are deemed to fall within the purview of this invention as claimed.

Continuing with the detailed description, and more particularly with the Vexplanation of Figure 4, the numeral indicates generally a block diagram showing the organization of the circuitry and components of the electronic control circuit utilized in actuating the clutch shown in Figure l. While the block diagram of Figure 4 is of the greatest utility in identifying the functions of the various stages and visualizing the intcrrelationship therebetween, the detailed theory of operation requires reference to the complete wiring diagram for the control circuit which is shown in Figure 5.

Turning therefore to Figure 5, and the mode of operation of the circuit shown therein, when the switch S1 is open, capacitor C7 charges from B-plus through R10. When roller-actuated microswitch S1 is closed C7 discharges through R32. A positive potential is then coupled through C10 and R18 onto the control grid of the triode V4 which serves as a trigger tube. Reference to the drawing will show that the anode or plate of V4 is directly connected to the positive terminal of the resistor R26 in the conventional rectifier circuit shown and that the positive plate supply voltage for tube V4 is derived therefrom.

When the grid of V4 is subjected to the positive potential, the tube conducts heavily, its cathode approaches B-plus potential, and a flow of electrons from the cathode yto the plate will occur. However, the cathode of V4 is connected to ground through resistors R22 and R25. Furthermore, the resistor R25 is located in the control grid circuit of the tube V5, and the iiow of electrons through R25 causes a positive voltage to occur between the control grid of V5 and ground, thus enhancing the conductivity of the tube. When V5 conducts heavily, the IR drop across common cathode resistor R23 places a high positive bias on the cathode of V6 thereby cutting V6 off and causing the net plate potential thereof to rise, and to maintain V5 conductive by applying the positive bias across R25 throughRZZ.

The tubes V5 and V6 are interconnected to form a conventional flip-dop circuit. The anode of V5 is coupled through a resistor R to the control grid of V6; conversely, the anode of V6 is coupled through resistor R22 to the control grid of V5. The capacitors C12 and C13 are connected in shunt across R20 and R22 respectively, and the control grids of both tubes are resistor-coupled to ground.

Since the circuit configuration and method of operation of the flip-dop circuit is well known to those skilled in the art, detailed description thereof is deemed unneces.` sary herein.

It is sufiicient for purposes of this specification to state that the flip-flop circuit as illustrated herein includes a pair of triode tubes V5 and V6 respectively and is a trigger circuit possessing two conditions of stable equilibrium. One condition is when V5 is conducting and V6 is cut olf; the other when V6 is conducting and V5 is cut off. The circuit remains in one or the other of these two conditions with no change in plate, grid, or cathode potentials, until some action occurs which causes the nonconductng tube to conduct. The tubes V5 and V6 then reverse their functions and remain in the new condition as long as no plate current ows in the cut-off tube. Because of this sudden reversal `from one-state of-equilibrium to the other, this type of circuit is referred to as a ip-op circuit by those skilled in the art.

Referring again to Figure 5, a flow of electrons takes place between the cathode and plate of V4 when positive voltage is applied through switch S1 to the grid thereof. This dow of electrons traverses R25 and R22 prior to reaching the cathode of V4. The voltage drop across R25 which occurs as a result of this electron flow raises the grid-to-cathode potential of the tube V5, and causes an increase in the plate current passing therethrough.

This increase in plate current through V5 increases the potential drop across the plate-line resistor R19 and decreases the net plate potential applied to V5; since the plate of V5 is coupled to the grid of V6, the voltage applied to said grid decreases correspondingly and reduces the plate current of V6. This decrease in the plate current of V6 gives rise to an increase in the net potential on the plate electrode thereof, and because of being coupled to the grid of V5, causes an increase in the grid potential and in the plate current passing therethrough. This phenomena is cumulative, and continues until the tube V5 conducts its saturation current and tube V6 is completely cut olf.

When the grid of V6 is exposed to a voltage pulse at a later instant, the process reverses itself and the circuit assumes a second stable state in which V6 conducts its saturation current and V5 is cut off. The reversal from one state of equilibrium to the other occurs so rapidly as to be almost instantaneous.

When the flip-flop occupies a state of equilibrium during which V5 conducts heavily, as a result of the conduction through the tubes V4 and V5 which followed thc closure of S1, no plate current flows in the tube V6. Consequently, no potential drop exists across R21 and the plate electrode of V6 is at a high potential. However, the plate electrode of the tube V6 is coupled through capacitor C14 and resistor R8 to the control grids of thc triode V7 and controls the degree of conductivity thereof. The tube V7 may comprise a conventional duplex-triode with a common plate connection, and a common cathode connection, as illustrated.

Whenever V5 conducts heavily, an increased voltage is coupled from the plate of V6 to the tube of V7, which functions as a power amplifier. The high plate potential during the cut-olf period of V6 is coupled to V7 through the long time constant of the RC circuit C14 and R27. The tube V7 normally conducts very little, and the positive pulse coupled thereto causes V7 to conduct heavily and apply a positive pulse between terminals A and B due to the IR drop across R28. The tube V7, as will now be obvious, is connected in a cathode-follower circuit. It will be observed that the plate voltage for V7 is supplied directly from the positive terminal of resistor R26 and that the load impedance R28 is connected in the cathode circuits of the tube. The waveform of the voltage coupled from the plate of V6 to the grid of the cathode-follower V7 will appear, slightly reduced in amplitude, across the said load impedance R28. Thus, amplification of power is obtained, along with the added advantage of low distortion of the input signal. Since the circuitry and mode of operation of the cathode-follower circuit are well known to those skilled in the art, no exhaustive treatment thereof is necessary in this specification. The positive pulse to V7 is terminated with the incidence of the next positive pulse supplied the grid of V6 by arelaxation oscillator to be discused hereinafter. The resultant decrease in the plate potential of V6 continues until the next positive pulse from V4 causes conduction in V6 to cease, as previously explained.

Across the output of the cathode-follower, there is connected a conventional resistor-capacitor differentiating circuit comprising R29 and C15, respectively. VContacts A and B are connected across C15, and contacts B and C are connected between the junction of C15- R29 and ground. y

The voltage across contacts B and C, which represents the differentiated output,.is applied `to the gas tetrode V8.

' In general, the voltage available between contacts B and C, (the latter of which is grounded), will comprise a trigger pulse of very short duration characterized by a sharp leading edge. More particularly, the differentiation accentuates the sudden change in the amplitude of the voltage across R28 which occurs whenever switch S1 and trigger tube V4 actuate the flip-flop circuit, and the positive pulse from the plate of V6 suddenly increases the conduction through the power amplifier tube V7.

The contact B of the differentiating circuit is connectedv to the control grid of the gas tetrode V8, and contact C is connected to the cathode circuit of the tube V8, thus elfectively placing one side of said cathode and filaments at ground potential. The cathodes and filaments of thyratrons V9 and V10 are connected in parallel with" the cathode circuit of V8, and have a similar connection between one side and ground. A filament transformer T1 is provided with a primary winding suitable for connection to a conventional A.C. supply, and a secondary winding to furnish power to the common cathode-iilamentv4 circuits of the tubes V8, V9, and V10.

The gas tetrode V8, which may be of the type known commercially as an FG-l05, operates with a plate potential of about 210 volts D.C. This 210 volts is securedy by means of the selenium rectiliers SR3 in series with re-Y sistors R2 and R9 and the secondary winding of transformer T2. An 80 microfarad capacitor C4 is connected f in shunt across the resistor R2.

voltage pulse from terminal B is applied to the control grid of the gas tetrode V8 the tube will become conductive, and will allow the capacitor C4 to discharge rapidly through the windings of the electromagnetic clutch. Following this, the FG-lOS extinguishes. This eifectively provides the clutch with a very sharp energizing pulse l which quickliy closes it.

Once closed, the clutch is held in that position by the pulsating direct current which is supplied its windings by the thyratrons V9 and V10, until termination of the control pulse which is supplied to the grids thereof as will be explained presently.

The primary windings of transformers T5 and T6 are connected to receive alternating current from a suitable supply. These windings are shown in Figure 5 as being connected in parallel with the primary winding of transformer T2. The secondary windings of transformers T5 and T6 are connected in series and the juncture therebetween is connected tothe contact X. The opposite ends of the joined secondaries, T5 and T6, are connected to V9 and V10, respectively. The voltage available between 1 contacts A and C is simultaneously applied between the control grids and cathodes of both tubes. Resistors R3 and R1 are interposed in the control grid circuits of the tubes V9 and V10, respectively.

Connections are such that when V10 receives a positive plate voltage from the secondary winding of T6 the gas triode V9 will experience a negative plate voltage, and vice-versa. In operation, when the plate electrode of V10 is positive, and the voltage pulse between control grid and cathode is delivered via contacts A and B, a iiow of electrons will migrate to the anodeof V10, from the anode to the secondary windings of T6 and the juncture between T6 and T5, through the windings of the electromagnetic clutch connected across X and Y, and back to the cathode of V10, thus completing the circuit.

Because of the method of connecting transformers T5 and T6, a negative plate potential is impressed upon tube V9 during the conduction period of V10. However, when the polarity Vof the alternating voltage supplied to the primaries of T5 and T6 reversesya positive potential is then impressed upon the anode of the tube V9 and said tube conducts to the exclusion of tube V10. This, it will be seen that once the clutch is closed by the current discharge from capacitor C4, it is held in this position by the pulsating unidirectional current supplied by the two thyratrons V9 and V10. This condition persists until the voltage supplied to the control grids of V9 and V10 from contacts A and B is removed.

It is appropriate at this point to state that only the function of the circuit in switching the gas tubes On had been described and that it is necessary to complete the description by explaining how the thyratrons are switched Off, to de-energize the clutch.

In Figure 5, the primary winding of the transformer T115 is energized by alternating current at commercial amplitude and frequency. The secondary of T115 feeds a regulated power supply. This power supply is of conventional construction and no claim herein is directed thereto. It is sufficient for purposes of this specification to state that said power supply is equipped to receive an alternating current input and deliver a substantially constant unidirectional output of approximately 150 volts. While the regulation of output Voltage may be secured by the type of regulated power supply which utilizes a gaseous regulator tube, such as the type known commercially as an 0A2, it will be understood that other types of regulation are equally suitable and that the invention is not limited to any particular type.

The voltage from the regulated power supply is sup- 'plied to a relaxation oscillator which includes the gas diode V1, the parallel capacitors Cil and C3, and the resistor R31. Charges from the regulated power supply are fed to the common plates of the capacitors C1 and C3, the other common plate of which is connected through resistor R31 to ground.

Tube V1 is of the gaseous type, and is characterized by being non-conductive until a certain critical voltage is applied between its anode and cathode. When the sum of the potential across capacitors C1 and C3 in parallel and the IR drop across R31 reaches the ignition value of V1, the tube tires or becomes conductive and said capac itors are permitted to discharge through resistor R31 and the tube. The action is essentially a repetitive one, and will occur at some readily controllable characteristic frequency. As is well known by those skilled in the art, when charge is reduced so that the voltage across V1 is reduced below the extinguishing potential, V1 becomes non-conductive and capacitors C1 and C3 begin charging. The capacitor C3 is variable, and may comprise a conventional decade-capacitor. The value of capacitor C3 may `be readily altered to increase or decrease the frequency ofthe relaxation oscillator.

The periodic negative pulses appearing across R31 are coupled by means of C8 and R12 to the control grid of tube V2, which serves as a buffer ampliiier. These pulses are amplified by the tube V2, given a phase reversal thereby. The resulting positive pulses are thencoupled to the grid of trigger tube V3 to periodically enhance the conductivity thereof.

The cathode of the trigger tube V3 is connected through resistor R20 and R24 to ground, and the control grid of V6, of the ip-ilop circuit is connected to the juncture between these resistors. When the trigger tube V3 becomes conductive, electrons liow up from ground through R24 and R20 to the cathode thereof and drive the cathode potential sharply positive; this positive pulse raises the grid potential of tube V6 and accordingly enhances the conductivity of this tube.

Tube V6, as a result of this positive voltage on its grid, will begin to draw current, and, in accordance with the well known principles of operation of a ip-op circuit as earlier discussed, will almost instantaneously .begin conducting heavily. Tube VS which previously conducted 11eavily,fnow becomes cutofgtube V6, which :was previously cut offnow conducts its saturation current. This increase in current through R21, the platefload resistor of *V 6, substantially reduces the net positive potentialpresent at the plate thereof to a point below the normal B-plus potential. Since the anode 4of V.6,is coupled to the grid ofthe power amplifier V7, Athis ,diminution in voltage substantially decreases the conductivity of that tube, and

eliminates current conduction through the cathode resistor -supply voltage to the trigger tubes V3, V4, the triodesVS,

V6, and the power amplifier V7.

`It will now be seen that the electromagnetic clutch 4 is repetitively energized and de-energized in response vto vthe changes between the two states of stable equilibrium of the ip-iiop circuit. Accordingly, the high-speed drive during the period in which the clutch is energized, delivers torque to the viscose pump and causes the extrusion of a greater Weight of viscose per unit time, thus effecting a thick portion in the yarn, substantially as described hereinbefore.

It will be apparent from the foregoing that Ihave provided a novel and practical electronic circuit with associated .apparatus for carrying out the several desired objects of the invention.

Itis to be understood that certain changes, alterations and substitutions can be made without departingfrom the spirit and scope of the appended claims.

What is claimed is:

1. An electronic control useful in the-manufacture of thick-and-thin yarn comprising a circuit having tirst and second stable states, means for triggering said circuit aperiodically from thefrst to the second of said stable states, means for triggering said circuit periodically from the second state back to the first state, and means to receive an output signal from said circuit.

2. An electronic control comprising a flip-1iop circuit having iirst and second stable states, means including a mechanically actuated switch for triggering said circuit aperiodically from the iirst to the second of saidstates, electronic means for restoring said circuit periodically to the first state, and electronic means to receive an output signal from said circuit.

3. An electronic control circuit useful in the manufacture of thick-and-thin yarn comprising a` pair of triodes each having iirst and second stable states, means for triggering one of said triodes aperiodically into the first state while maintaining the other of said triodes in the second state, means for triggering said other triode periodically into the first state while maintaining said one triode in the second state, and means to receive an output signal from said circuit.

4. .'Antelectrovnic control useful in themanufactpre of thickfand-thin yarn comprising aipdiop circuit including a 2pair of ytriodes .each having stable conductingand vnon-,cond u cting states, means including a mechanically actuatedswitch fortriggering one of said triodes aperiodically into va conducting state While maintaining the other l,of said triodes in a non-conducting state, electronic means vfor triggering said other triode periodically into a conducting state while maintaining said one triode in a nonconducting state, and means to receive a recurring signal 5 An electronic control comprising a pair of triodes, means interconnecting the anode of one triode to the control grid of the other triode, and vice versa, in order to forni a circuit having bistable states capable of proclucing a-recurring signal, aperiodically actuated means vforftriggering said triodes from a iirst to a sec/ond of saidbistable states, 4periodically actuated means for restoring said triodes to the iirst of said states, and means'to reccivethe recurring signal from said circuit.

6. An electronic control useful in the manufacture of ,thick-andrthin yarn comprising a pair of triodes, means interconnecting vthe anode of one triode to the control grid of theother triode, and vice versa, in order to form a vcircuit having bistable states capable of producing a recurring signal, switch means aperiodically actuatedme- ,chanically Yfor triggering said triodes from a iirst to a second of said bistable states, oscillator means for periodirestoring said triodes to the iirst of said states, and

ymeansforreceiving the recurring signal from said circuit and for. converting the same into useful work.

7. 4Anelectronic control circuit for actuating an .electrically ,responsive device comprising a plurality pf nory mallly nonfconductive gaseous Vspace discharge units adapted to deliverr an output signal when rendered I conlnctivqtirstand second trigger tubes, a switch `connected .to pulse the iirst of saidtrigger tubes and to institute aperiodic vl conduction therethrough, a relaxation osciliator connectedtoipulse the second of said trigger tubes andv to institute periodic conduction therethrough, a fliptiop circuit vhaving a first Itriode connected to conduct heavilyin response-to `conduction through said first trigger tube and a second triode connected to conductheavily in response to conduction through said second trigger tube, means connecting said second triode'to said gaseous space discharge units to institute conduction therethrough inresponse to heavy conduction of said second triode, means connected to receive the output signal delivered by saidvgaseous space discharge units, and means for supplying p oyver to the components of said control circuit.

References Cited in the le of this patent UNITED STATES PATENTS

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