US 3537660 A
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N v- ,1970 HISCHIPPERS ETAL 3,537,660
REGULATING SYSTEM FOR WINDING DEVICES FOR THREADS 0R THREADLIKE STRUCTURES Filed Aug. 17, 1967 2 Sheets-Sheet 1 mvemoas: HEINZ SCHIPPERS HANS LOHEST WOLFGANG WEBER ERICH LENK ATT'YS ,1970 H. SCHIPPERS ETAL 3,537,660
- REGULATING SYSTEM FOR WINDING DEVICES FOR THREADS OR THREADLIKE STRUCTURES Filed Aug. 17, 1967 2 Sheets-Sheet 2 INVENTORS'.
HEINZ SCHIPPERS HANS LOHEST WOLFGANG WEBER- ERICH LENK United States Patent 01 lice 3,537,660 REGULATING SYSTEM FOR WINDING DEVICES FOR THREADS R THREADLIKE STRUCTURES Heinz Schippers and Hans Lohest, Remscheid-Lennep, Wolfgang Weber, Wuppertal-Elberfeld, and Erich Lenk, Remscheid-Lennep, Germany, assignors to Barmag Barmer Maschinenfabrik AG., Wuppertal, Germany Filed Aug. 17, 1967, Ser. No. 661,430 Claims priority, appliclzgltig iyl s(icrmany, Aug. 18, 1966,
Int. (:1. B6511 59/38 U.S. (:1. 242-45 4 Claims ABSTRACT OF THE DISCLOSURE This invention relates to winding devices and, more particularly, to apparatus for suppressing variations in thread tension during winding operations.
In winding operations, it is essential that the thread or other material being wound is maintained at a substantially constant tension in order to achieve a uniform product. It is, therefore, necessary to monitor and control thread tension and to make adjustments when the tension varies from some predetermined value. Obviously, it is most desirable to have the monitoring and regulation of thread tension accomplished automatically during the winding process.
It is a known practice to use a sensing lever to determine thread tension or winding diameter. The sensing lever is used in conjunction with a rotary transformer to regulate or control drive motor speeds. In addition, servo motor control has been proposed for winding drives. The servomotor, operating in conjunction with an inductive pickup, transmits an electrical signal, corresponding to the magnitude of the sensing lever deflection, to the winding drive control circuitry. This system tends, as experience has shown, to pendulate or oscillate, since the inductive pickup has ordinarily not returned to its zero or null position at the time the drive motor has been regulated to the proper speed, and consequently, the drive motor receives further control impulses causing an overcorrection. In order to avoid this pendulation and to achieve a proportional-integral regulation, it has been proposed to control the servomotor over a potentiometer. The con-' trol winding of the servomotor lies in the zero branch of a bridge circuit and is connected to an auxiliary voltage between the inductive pickup and a resistor on the one hand and a potentiometer tap on the other. The use of such a potentiometer continuously operated by a servomotor brings about a severe wear on this element.
It is therefore an object of the present invention to provide a completely contactless, simple, maintenance free system for the regulation of winding or spooling drives as a function of thread tension.
It is a further object of this invention to provide a system for the regulation of winding or spooling drives which is free from pendulation or overcontrolling tendencies.
In general, the present invention consists of apparatus for regulating winding drives to achieve a substantially 3,537,660 Patented Nov. 3, 1970 constant thread tension. In one embodiment of the invention a sensing lever is situated in a thread loop. The thread loop is arranged such that the depth of the loop is a function of the thread tension. Variations in thread tension as indicated by corresponding variations in loop depth are transmitted by means of the sensing lever to a contactless generator. The contactless generator consists of a rotary transformer, one winding of which is connected to the alternating current main; the other winding being connected to the input of an amplifier of conventional design. The displacement of the sensing lever is transformed in the rotary transformer into a proportional or approximately proportional electrical control current. This control current is amplified and passed to the input of a thyristor circuit or other transducer. The output side of the thyristor circuit is connected to the take-up spool drive motor. The thyristor circuit, which is also connected to the alternating current main, rectifies the alternating current and passes the resulting direct current to the drive motor. Variations in control current fed to the input of the thyristor circuit cause corresponding changes in current delivered to the drive motor, and accordingly, in drive motor speed. Consequently, variations in thread tension cause the drive motor speed to be altered such that the thread tension tends to remain constant.
This arrangement presents considerable advantage over the known regulating or controlling devices. For example, the load on the rotary transformer windings is very low, and accordingly the torque associated with displacement of the rotary transformer winding is low. In contrast, displacement of a rotary transformer winding which carries motor feed current, causes a great load on the thread. Similarly, the present invention dispenses with both a servomotor and potentiometer. Moreover, the regulating system, thus simplified, is, because of the use of contactless structural elements, less subject to breakdown. Further, by using the rotary transformer as a contactless generator instead of a regulating transformer, no mechanical wear takes place. In addition, although the contactless generator is specified above as a rotary transformer, a semiconductor, whose electrical conductivity is variable by light or magnetic or electrical fields, can be used instead.
Various modes of regulation may be obtained by providing, in the regulating circuit of the sensing lever or other sensing device, a mechanical-pneumatic damping or regulating member with proportional-integral behavior and/or differentiating rate-time behavior. This damping or regulating member can be coupled or securely connected to the sensing lever or other sensing device. The damping or regulating member is designed in such a way that it brings about a rapid and desired modification of the drive motor speed to compensate for a change in thread tension and automatically regulates the tension back to its normal value.
It is further proposed to use the damping or regulating member with an axially movable feeler prong which is adjustably biased by means of a spring and pneumatic piston and cylinder arrangement. The feeler prong is connected over a hinged lever and rod system to the control member of an inductive generator. In the lever rod system, both spring and adjustable pneumatic forces are powers, it is also possible in accordance with the present invention to utilize an alternating current drive motor in conjunction with two thyristors arranged in an inverse parallel circuit with an alternating current output, or with a triac or transducer with alternating current output. The drive motor is constructed as an alternating current slip rotor motor with raised rotor resistance. The two thyristor circuit, the triac or the transducer, whichever is utilized, is arranged between the amplifier and the drive motor. Here, the use of the triac or transducer is to be peferred over the two thyristors, since the triac and the transducer are supplied as single structural elements.
The invention can be more fully understood by reference to the attached drawings which contain schematic representations of various embodiments of the invention:
FIG. 1 shows the regulating system of a winding device wherein the speed of the direct current drive motor is controlled as a function of thread tension;
FIG. 2 shows the regulating system of a winding device wherein the speed of the alternating current drive motor is controlled as a function of thread tension;
FIG. 3 shows the applications of a damping or regulating member in the system described in connection with FIG. 1;
FIG. 4 shows the application of a damping or regulating member in the system described in connection with FIG. 2; and
FIG. 5 shows an example of the execution of the damping or regulating member.
In FIG. 1, thread 1 passes over deflection rollers 2 and 3 and is wound on spool 4. Dancer roller 5 is arranged to reside on thread 1 between rollers 2 and 3. Dancer roller 5 is mounted on one end of swinging arm 6. The other end of arm 6 is attached to rotor shaft 7. Rotor shaft 7 is turnable only through an angle of about 90. Rotor 8, which is mounted on rotor shaft 7, and stator 9 are the principal components of a contactless rotary transformer, used in known manner as an induction generator (a device for converting position changes to electrical impulses). Stator 9 is connected over terminals 10 and 11 to lines 12 and 13 of the alternating current main. Rotor 8 is electrically connected through spiral springs 14 and 15 and lines 16 and 17 to the input of amplifier 18. Spiral springs 14 and 15 are arranged on rotor shaft 7 such that one spring is situated clockwise about shaft 7 and the other spring is situated counterclockwise about shaft 7. Amplifier 18 is connected to lines 12 and 13 of the alternating current main through lines 19 and 20. The output of amplifier 18 provides control current to thyristor circuit 21 over lines 22 and 23. Thyristor circuit 21 draws energy from lines 12 and 13 of the alternating current main over conductors 24 and 25. The output of thyristor circuit 21 is connected over conductors 26 and 27 to the armature circuit 28 of drive motor 29. Drive motor 29, which provides the rotational power for spool 4, can be a conventional type direct current motor. Preferably, however, a brushless direct current motor is used wherein electronic commutation is employed thereby eliminating the wear points present in a brush type motor. Field winding 30 of the drive motor 29 is externally excited with direct current supplied over leads 31 and 32 from rectifier 33. Rectifier 33 receives its input current from leads 12 and 13 of the alternating current main through conductors 34 and 35. In normal operation, thread 1 is wound on spool 4 driven by motor 29. Thread 1 passes over deflection rollers 2 and 3 and forms a loop under the weight of dancer roller 5. The length of this loop varies according to thread tension. If, for example, the thread tension decreases, then the thread loop lengthens, and the dancer roller 5 follows the bottom of the loop causing swinging arm 6 to turn rotor shaft 7 on its longitudinal axis clockwise through a small angle. Rotor 8 mounted on rotor shaft 7 will turn through a correspondingly small angle with respect to stator 9. The current induced in rotor 8 now changes and flows in correspondingly modified magnitude to amplifier 18. The amplified current passes over conductors 22 and 23 to thyristor circuit 21 which controls the armature current of motor 29. Thyristor circuit 21 rectifies the alternating current fiowing in conductors 24 and 25 and delivers the resulting direct current to armature circuit 28 over conductors 26 and 27. The armature current is therefore modified in accordance with the variation in amplified control current delivered to thyristor circuit 21 causing a corresponding change in drive motor speed. Spool 4, driven more rapidly in this manner, now draws off the thread with a higher tension. The thread loop shortens and the whole process is repeated in the reverse direction. The regulation takes place whenever the position of swinging arm 6, and, simultaneously, rotor 7 deviates from a certain desired value. The corrective regulation continues until the actual value of thread tension agrees with the desired value. It should be noted that while FIG. 1 shows the power source as single phase alternating current, three phase current may also be utilized.
FIG. 2 is a schematic representation of a thread winding system using an alternating current drive motor. Thread 1 passes over deflection rollers 2 and 3 and is wound on spool 4. One end of an axially slidable feeler prong 36 is arranged to contact thread 1 as shown. Semiconductor 38, which is situated generally within the magnetic field of magnet 37, is mounted on the other end of prong 36. Semiconductor 38 which serves as a contactless pickup or sensor, will undergo variations in its electrical conductivity as it is moved into the field of magnet 37. Semiconductor 38 is electrically connected through leads 39, 40, 16 and 17 to the input of amplifier 18. Amplifier 18 obtains its power from leads 12 and 13 of the three phase alternating current main through connections 19 and 20. The output of amplifier 18 provides control current over leads 22 and 23 to the input of control circuit 41. Control circuit 41 may consist of two thyristors connected in inverse parallel circuit to permit bi-directional current fiow. A single triac element can be used instead of the two thyristors to accomplish the same function. Control circuit 41 receives its main current feed from leads 12 and 13 of the three phase alternating current main over conductors 24 and 25. The output of control circuit 41 is connected over leads 26 and 27 to one winding of alternating current motor 42. The other winding of motor 42 is connected to leads 43 and 44 of the three phase alternating current main through conductors 45 and 46. Alternating current motor 42 provides the rotational drive for spool 4. The two coils of motor 42 receive an alternating current displaced in phase by substantially from one another. In normal operation, an increase in thread tension would correspondingly cause semiconductor 38 to plunge deeper into the field of magnet 37. The resulting current modification in semiconductor 38 acts upon amplifier 18 with controlling effect on circuit 41. In the process the feed current to motor 42 would be reduced and the turning rate of spool 4 would decrease. A reduction in thread tension would accordingly bring about an increase in motor current and, thereby, in the turning rate of the spool.
In FIG. 3, a mechanical-pneumatic damping of regulating device 47 is shown interposed between swinging arm 6 and rotor shaft 7 of the system described in connection with FIG. 1. In FIG. 4 a mechanical-pneumatic damping or regulating device 48 is shown interposed between the sensing prong 36 and semiconductor 38 described in connection with FIG. 2. The damping device, which will be described in detail later in connection with FIG. 5, permits rapid reaction to signficant variations in thread tension but prevents reaction to small tension fiucuations which normally occurs.
The damping or regulating device shown in FIG. 5 has an axially slidable feeler prong 36, one end of which is urged against thread 1 by spring 71. The pulling force of spring 71 on feeler prong 36 is adjustable for various thread denicrs by means of screw 49 mounted in casing 72. At the other end of the feeler prong 36 there is situated a piston 50 which moves in a cylinder 51. From the bottom of cylinder 51 lines are connected to two valves 52 and 53. Valve 52 closes on the pressure stroke of piston 50. Valve 53 closes on the suction stroke of piston 50 and is kept closed at the beginning of the pressure stroke by the bias determined by the setting of screw 54 and spring 55. The air forced from cylinder 51 after valve 53 opens is released through line 56. At point 57 on feeler prong 36 there is articulated a lever rod 58. At point 59 on rod 58, there are articulated a pressure spring 60 and a piston rod 61. Piston 62, which is mounted on piston rod 61, is situated in cylinder 63. An outlet 64 which is shown at the bottom of cylinder 63, is provided with adjustable choke 65. The pressure spring 60 is supported on the casing. At point 66, there is articulated a carrier rod 67 holding semiconductor 38 such that semiconductor 38 can be moved into the field of magnet 37. Semiconductor 38 is connected over lines 39, 40, 16 and'17 to the input of amplifier 18 (FIGS. 1 and 3). At the upper end of the lever rod 58 there engages a pressure spring 70, which is supported on the casing.
At normal thread tensions, springs 60' and 70 and the pressure exerted by thread 1 on prong 36 counterbalance the effect of spring 71. Piston 50, cylinder 51 and valves 52 and 53 perform a damping function such that the system does not react to small tension fluctuations, which always occur, for example, during the thread distribution process.
If the thread tension variations exceed a predetermined value, then the damping and regulating member responds. If, for example, a thread tension drop occurs, then the feeler prong 36 is drawn, only slightly damped by the pulling force of spring 71, against the slackening thread to the right. At the first instant of the tension drop, the point 59 is a fixed pivot point for the lever 58, since the piston 62, because of its damping action, will not move quickly. Simultaneously then, semiconductor 38 is rapidly drawn into a weaker zone of the field of magnet 37. Thereby the current flowing through semiconductor 38 is reduced causing the control circuitry to act upon the magnitude of the feed current to the drive motor so as to increase its turning rate. After the thread tension drop has stopped, point 57 on prong 36 becomes a pivot point. The piston 62 slides still somewhat further to the right whereby semiconductor is plunged into the field of magnet 37 causing a reduction in the turning speed of the drive motor.
In the case of an increase in thread tension, the movement of feeler prong 36 can be damped more positively by piston 50 and cylinder 51 than in the case of a thread tension decrease. The further course of the regulating action then corresponds to that described above.
The damping device operates in such a way that the movement of the feeler prong 36 first rapidly displaces the semiconductor 38. The regulating pulse thereby generated changes the turning rate of the drive motor of the machine. The resetting of the impulse generator that takes place, however, is damped by reason of the special attuning of the lever arms and forces. As viewed from the standpoint of regulating technology, the regulator presents a proportionabdifferential behavior, because the initiating command is given proportionally to the displacement of the feeler prong; but the resetting command for'its return is given diflerentiated. With reference to the thread, the device acts as a proportional-integral regulator, since the modification of the excursion of the feeler prong is equal to the difierence between the surface integrals of the triangles made by the deflection rollers 2 and 3 and the thread bend, and because this difference is determined over a proportional member.
The impulse generator described in FIG. 2 consisting primarily of prong 36, magnet 37 and semiconductor 38 can also be employed in place of the rotary transformer described in connection with FIG. 1 for the regulation of the direct current motor 29. Likewise, the rotary transformer described in connect-ion with FIG. 1 may be utilized in place of the impulse generator described in connection with FIG. 2 to control the alternating current motor 42. Furthermore, both the rotary transformer and the sensing prong with its attached semiconductor can be replaced by a photoelectrically controlled impulse generator.
In further development of the present invention, the winding of materials other than thread can also be con trolled. Such materials might include band-type thread structures, film strips, and the like. Similarly, it is possible to use the regulating system described above by sens ing the growing diameter of a winding rather than the thread tension. This type of control is fully suflicient in many cases such as the rewinding and draw-ofl of thread from a resting delivery bobbin. It is also possible, to use a program control of known type instead of sensing the Winding diameter. It is also possible, for example, to use a cam plate control in conjunction with other means of thread tension regulation. The cam plate control would be used for coarse regulation, whereas the fine regulation could be accomplished as a function of thread tension. Such an approach has the advantage that movements of the dancer roller or sensing prong remains very slight and any possible thread tension oscillation is avoided.
Obviously m-any modifications and variations of the invention as hereinbefore set forth may be made without departing from the spirit and scope thereof and therefore only such limitations should be imposed as are indicated in the appended claims.
1. Regulating apparatus for accurately maintaining a predetermined thread tension, said apparatus comprising in combination:
(a) a spool means upon which to wind the thread;
(b) a two winding alternating current drive motor;
(c) control means operatively associated with said drive motor, said control means having an input arranged such that variations in control signal levels appearing at said input will cause corresponding variations in the speed of said motor means, the output side of said control means being connected to one winding of said alternating current motor;
(d) sensing means including an axially movable feeler prong arranged to detect variations in thread tension;
(e) amplifier means having an input and output, the input of said amplifier means being connected to the output of said sensing means, the output of said sensing means being connected to the input of said control means; and
(f) damping means operatively coupled to said sensing means, said damping means comprising in combination with said axially movable feeler prong (1) spring means for holding said feeler prong in contact with the material being wound;
(2) a lever means pivotally connected to said feeler (3) a first piston and cylinder means operatively connected to said lever for providing a damping action on the forward movement of said feeler P .(4) a second piston and cylinder means operatively connected to said feeler prong for providing a damping action on the rearward movement of said feeler prong;
(5) fixed spring means connected to said lever means for positioning and balancing said lever; and
(6) output means connected to said lever for transmitting the regulated excursions of said feeler prong.
2. Regulating apparatus in accordance with claim 1 wherein said control means includes a two thyristor circuit wherein said thyristors are arranged in inverse parallel configuration to permit bi-directional current flow, the output side of said two thyristor circuit being connected to one winding of said alternating current motor.
3. Regulating apparatus in accordance with claim 1 wherein said control means utilizes a triac to achieve bidirectional current flow, the output side of said tri ac being connected to one winding of said alternating current motor.
4. Regulating apparatus in accordance with claim 1 wherein said sensing means includes:
(a) a pair of roller means in axially spaced relationship;
(b) an axially slidable feeler prong means having two ends, one end arranged to contact the thread between said roller means;
(c) adjustable spring means arranged to urge said feeler prong means against said thread;
References Cited UNITED STATES PATENTS Stack 242-45 Dunigan 318-6 X Ash 242-45 Lohest 242-45 X Cohen 242-45 Bonikowski 24245 X STANLEY N. GILREATH, Primary Examiner