Patent Publication Number: US-3878671-A

Title: System for measuring the twist of spun yarn in open-end spinning

Description:
[ Apr. 22, 1975 SYSTEM FOR MEASURING THE TWIST OF SPUN YARN IN OPEN-END SPINNING [75] Inventors: Pavel Seidl; Milos Mladek, both of Usti nad Orlici. Czechoslovakia [73] Assignee: Elitex Zavody textilniho strojirenstvi, generalni reditelstvi, Liberec, Czechoslovakia [22] Filed: Sept. 17, 1973 211 Appl. No.: 397,741  
 [30] Foreign Application Priority Data Sept. 15. 1972 Czechoslovakia 6323-72 [52] U.S. C1 57/34 R; 57.89 [51] Int. Cl. D0lh 13/32; DOlh 1/12 [58] Field ofSearch 57/58.8958.95.  
 [56] References Cited UNITED STATES PATENTS 2.982.083 5/1961 Brcitcnbach 57/97 3.660.972 5/1972 Neill et a1. 57/34 R 3.678.673 7/1972 Prochazka et a1. 57/58.95 3.680.299 8/1972 Lee. Jr. 57/34 R 3.704.579 12/1972 Tooka et a1 57/34 R 3.791.128 2/1974 Landwehrkamp et a1. 57/93 3.803.823 4/1974 Niestron et a1. 57/34 R Primary E.\&#39;anziner.lohn Petrakes Attorney. Agent. or F irmMurray Schaffer [57] ABSTRACT An open end spinning unit having feed means for delivering fibrous material. a rotary twisting means for spinning the fibers into a yarn. and a rotary withdrawing means for taking up the yarn. A first detector is located to sense the revolution of said twist means and providing an output having a value proportional to the number of revolutions. A second detector is located to sense the revolution of the withdrawing means and providing an output having a value proportional to the number of revolutions thereof. The first detector is connected to the output of a first counter between which is interposed a gate means. The second detector means is connected to the input of a second counter. the output of which is connected to the input of the gate. and which provides a signal for controlling the gate. An indicator is connected to the first counter to record the value received by the counter.  
 4 Claims, 2 Drawing Figures RELATED CASES The present invention and disclosure is related to corresponding applications. Ser. No. 397.742 and Ser. No. 397.743, filed on even date hereith. Reference and incorporation of the subject matter disclosed therein is made as if more fully set forth herein.  
 BACKGROUND OF INVENTION The present invention relates to a system for measuring and indicating the twist number of spun yarn and in particular to a system for automatically measuring and detecting the twist imparted to the spun yarn in an open end spinning machine.  
  It has been known to determine the number of twists imparted to a spun yarn per unit length by separately measuring the number of revolutions made by the twist imparting member (i.e. the spinning turbine) and separately measuring the withdrawing speed of the spun yarn from the turbine. After these individual measurements have been made a further computation is manually obtained by dividing the data so as to obtain the theoretical number of twists per unit length. This system of determining the twist number is disadvantageous namely in that it requires two considerably different measurements to be individually taken. Each of these measurements requires the use of special and precise apparatus so that the computation which is later to be made may be as accurate as possible. Furthermore, the determination of the twist number of the yarn so spun is not a direct computation and as a consequence the resultant determination may not be accurate because of a number of factors not related to the actual spinning operation.  
  It has been known to measure the twist number of spun yarn by untwisting a given or predetermined length of the yarn sample. By untwisting such a sample it is possible to determine the actual number of twists in the given sample with respect to the drop in tension between the twisted and untwisted yarn. The measurement of the twist number of yarn in this manner re- I quires an interruption of the spinning process in order that the predetermined sample length may be taken. Thus this system is not suitable for an instantaneous determination of the twist number of the yarn as it is being manufactured and during the actual spinning process. Furthermore. due to the character of the yarn structure an accurate result cannot be expected since many errors can arise during the untwisting of the given length of yarn and during the actual measurement of the tension drop.  
  It is the object of the present invention to provide a system for the automatic measurement and indication of the twist number of spun yarn directly from the spinning unit during the spinning operation.  
  It is a further object of the present invention to provide a simple and reliable apparatus and system enabling the measurement and indication of the twist number during the spinning operation without requiring any additional or manual calculation.  
  It is a further object of the present invention to provide a system for measuring and indicating the twist number of the yarn without the need to interrupt the spinning operation or to shut down the spinning machine.  
 LII  
  The foregoing objects, other objects and numerous advantageous will be seen from the following disclosure of the present invention.  
 SUMMARY OF THE INVENTION According to the present invention there is provided a system for measuring and indicating the twist factor or twist number of the yarn spun in an open end spinning unit. Open end spindleles spinning machines comprise a plurality of units each having feed means for delivering fibrous material. a rotary twisting means for spinning the fibers into a yarn and a rotary withdrawing means for taking up the yarn. In accord with the present invention there is located a first detector means by which the revolution of the twist means is sensed and which provides an output having a value proportional to the number of its revolutions. A second detector means is located sensing the revolution of the withdrawing means and providing also an output having a value proportional to the number of its revolutions. The two sensed values are evaluated in a circuit to which the input from the first detector is connected to a first counter. A gate means is interposed between the first detector and the first counter. The second detecting means has its value output connected to the input of a second counter, the output of which is itself connected to the input of the gate. The second counter is so regulated that it provides a signal operating the gate after a predetermined input value is fed to it. Upon the passage of the signal to the gate. the first counter is blocked from further input and is caused to transmit its received cumulative input to a digital or analog indicator.  
  Preferably. the second counter is provided with a decade number switch by which its input value may be decimally modified so that its input may be provided over a broad range. Further, it is preferable that the det ectors be contactless and comprise preferably. photoelectric cells which are adapted to sense optical indicia or markings placed on the twist means or spinning turbine and the rotary withdrawing means without interference with their operation.  
  Further details of the present invention are described in the following specification and are shown in the form of its exemplary embodiment in the accompanying drawings.  
 BRIEF DESCRIPTION OF THE DRAWINGS In the drawings:  
  FIG. 1 is a perspective view of a spinning machine showing the application of the present invention to at least one of the spinning units therein,  
  FIG. 2 is a circuit diagram of the evaluation unit employed and provided by the present invention.  
 DESCRIPTION OF INVENTION A more or less conventional spinning machine, of which there are many commercial embodiments available is depicted in FIG. 1. The machine comprises a frame 1 on which are aligned a plurality of spinning units, each comprising a rotary turbine 2 mounted to rotate about a horizontal axis 3. A silver 4 of fibrous material is withdrawn from a container 5 and passes through a dissolving and feeding mechanism 7 to be fed to the chamber of the spinning turbine 2 where under the effect of centrifugal action and suction it is spun into a yarn 7. The yarn 7 is withdrawn between a rotary take up beam 8 and a hold down arm 8a over a winding beam 9 to be wound on a bobbin 10.  
  In accordance with the present invention at least one of the spinning units has its twist imparting turbine 2 provided with a detector 11 adapted to sense its rotation. The detector 11 is mounted on the frame of the machine in opposition to the peripheral surface of the spinning turbine 2. which surface is provided with at least one marking indicia 12. The detector 11 and the markings 12 are arranged in such a manner that the output of the detector provides a series of pulse signals having a value proportional to the number of revolutions of the turbine 2. If one marking 12 is used the number in that case represents the number of passages of the marking 12 through the plane of the detector. Preferably, the optical marks 12 are formed on the point of the circumference of the turbine 2 so that light is reflected from the surface in a different manner than the remaining portions of the turbine. Preferably. the marking may be black. The detector is preferably a photoelectric cell sensing the change in light reflection or transmission and having electrical electronic means for producing a series of output pulses in response thereto.  
  The rotary withdrawing beam 8 is also provided with a detector 13 mounted in opposition to its circumferential surface on which is secured tape 14 itself provided with series of spaced optical markings 15. The detector 13 is similar to the detector 11 as are the optical markings 15 to the markings 12 on the turbine 2. Thus the detector 13 is capable of determining the rotation of the withdrawing beam 8 and produce an output signal comprising a series of pulses, the value of which being proportional to the number of revolutions of the withdrawing beam 8. In this instance the number of black marking optical indicia 15 are such that the number of passages they make through the plane of the detector during a single revolution is proportional thereto.  
  The outputs of the detectors l2 and 13 are fed into an evaluation and comparison circuit shown in FIG. 2. This circuit comprises a pair of detector inputs D and D which are adapted to be connected to the detectors 12 and 13 respectively. The detector input D. is connected to a gating means 16 which has its output connected to a first counter 17 which is adapted to transmit upon appropriate signal its accumulated value to a digitronic indicator 18 by which the accumulated value may be read out either in digital or analog form. The detector input D is connected to the input of a decade number switch 19, the outputs of which is connected to a second counter 20, the output of which itself is connected to the gating means 16. In general, the gate 16 is adapted to be normally open allowing passage of the input from the detector input D into the first counter 17 and is closed upon the reaching in the second counter of a predetermined value from the input of the detector input D In order to determine the twist number of the following relationship may be employed:  
 wherein: z is the twist number,  
  0 is the number of revolutions of the twist imparting element or turbine 2 during the withdrawal of a given length of yarn. and  
  L is the given length of yarn withdrawn over the withdrawing beam 8.  
  Preferably. one optical marking 12 is made about the circumference of the turbine 2 and the number of markings 15 made on the tape 14 secured to the withdrawing beam 8 is chosen in such a manner that the detector 13 arranged in opposition to it has a value proportional to the number of revolutions of the withdrawing beam which is I00 pulses after the withdrawing of one meter of spun yarn. In this case the detector 13 is connected by the decade number switch to the last two decades of the second counter 20. Thus the counter 17 and 20 begin to countsimultaneously the pulses from each of the respective detectors 11 and 13. And these pulses are continually accumulated in the respective counters. The initiation of the evaluation operation can be controlled by suitable control means regulating the operation of the gating means 16 either manually or automatically. Such a control unit is shown in the aforementioned co-pending applications. After initiation. the counters l7 and 20 accumulate the pulses delivered through the detectors. After pulses from the detector l3 sensing the rotation of the withdrawing beam 8 the second counter 20 is caused to emit a signal which is passed on to the gate 16. This signal causes the gate 16 to close and thus stopping the passage of pulses from the detector input D (detector 11) to the first counter 17. Thus the counter 17 ceases to count the number of pulses indicative of the revolution of the spinning turbine 2 with respect to one meter of yarn withdrawn over the beam 8. The first counter has thus accumulated the number of revolutions of the turbine 2 per 1 meter of the length of withdrawn yarn and thus provides a number of twists imposed upon the yarn per l meter of the length. This may be directly represented or read out on the indicating unit l8 either as a digital number or in some other analog fashion.  
  If the decade number switch 19 had been placed at some other position then the pulses fed to the second counter 20 would be most applied by a constant 10&#34; where K is an integral number the value of which depends upon the selection or adjustment of the decade number switch 8. As a result the first counter 17 would accumulate the number of revolutions of the spinning turbine per one meter of yarn multiplied by the constant 10&#34; The measurement time and thus also the accuracy of the result can be adjusted and varied by the use of this decade switch. In this connection it is also necessary to insure that the number indicated on the indicating unit 18 would be in proper relationship and accordance with the twist unit per number length, it is necessary to complete the numeric value with a decimal symbol. That is the decimal point must be placed in the read out number in a proper position between the digits on the indicating unit 18 as given by the position of the decade number switch 8 to compensate for the use of the constant factor 10 to the K power.  
  The present invention may also be employed for measuring and indicating the imparting of a false twist to the spun yarn. In this instance the number of false twists may be given by the following relationship:  
 -Continued n l n Z V 17m. l  
  In which n represents the number of revolutions of the twist imparting member of turbine per second.  
  V equals the withdrawing speed in meters per second. D the diameter of the twist imparting turbine in meters and the lambda equals the coefficient of shortening or reduction of the sliver or ribbon.  
  By reducing the complex additivefactor to the constant value K this relationship may be easily determined with the system of the present invention. The value K. in conventional twist imparting turbines. commercially available, approximates plus 5. the sign plus applying to the true or actual character of the yarn. This value varies so slightly between turbine units that it can be respected as a specific constant so that first counter 17 may be set at an initial value of 0005 instead of its initial zero value of 0000. By thus adding the value 5 to the counter 17. the resultant indicated value takes into account the influence of the complex computation of the withdrawing speed. diameter and coefficient as given above for each 1 meter of yarn which is withdrawn over the withdrawing beam 8 from the spinning turbine 2 during the measurement cycle. As a result the computation and indication of the measurement is directed and straightforward as previously described earlier.  
  lt is possible to modify the computation to provide a reading relative to l centimeter of withdrawn yarn rather than through 1 meter of withdrawn yarn. To obtain a pulse reading from the detector 13 for each 1 centimeter of yarn it is possible to provide a rotatable wheel engaging the surface of the withdrawing beam 8 which wheel contains the optical indicia sensed by the detector as a ratio of the rotation of the withdrawing beam 8. Such a system is shown in the aforementioned co-pending applications. In addition the number of revolutions of the withdrawing beam 8 can be obtained by any other suitable means by which the motion is coupled with the motion of the withdrawing beam 8. A simple brush and commutator device may be employed. Analogously the detector 11 which senses the motion of the turbine 8 can be arranged and coupled to the turbine 8 in any other manner than that described.  
  Should the spinning machine be provided with a mechanism by which the withdrawing speed may be automatically changed and adjusted. the use of the repeated measurements made in accordance with the present invention showing the twist number per 1 meter of yarn length, can be employed to continuously make such adjustment. This can be obtained by providing the counter 17 with preselection circuits. the outputs of which being responsive to the read out of the counter 17 so that the outputs may be used to regulate and control the operation of the withdrawing beam 8. Such preselection circuits may be employed for checking and maintaining the accurate spinning of each of the spinning units in the spinning machine.  
  It will be obvious from the foregoing that in accordance with the present invention the operation of each of the spinning units or the operation and adjustment of the entire machine can be easily and automatically checked. regulated and the twist factor determined. The apparatus is simple and does not require a constant attendance by the operator. The apparatus system may LII be manually controlled or it may be automatically operated asdesired. The present invention may be applied toany of the conventionally and commercially available machinery without extensive modification of such machinery. The location of the detectors 11 and 13 are the only mechanical or structural devices that need be installed. These can be installed without modification of either the turbine or the withdrawing beam 8. The operation requires only the selection of the measuring interval length that is whether the pulse is obtained are proportional to the meter of withdrawn spun yarn or to an amount greater or lesser than this. The indication of the result directly in digital form on the digitronic discharge tubes of the indicating device considerably facilitates their recording. This indicating device may be visually read. may contain memory storage and recording circuitry so that the read out can be maintained over periods of time. It has been further found that the accuracy of measurements is quite high since the mechanical adjustment to produce optical markings 12 on the spinning turbine per l unit meter length input upon withdrawal of 1 meter of yarn over the withdrawing beam 8 is approximately plus or minus one twist per meter and upon withdrawing 10 meters of yarn is plus or minus 0.1 twist per meter yarn length.  
  As defined herein a counter is a device or circuit which counts input pulses. accumulates or stores the pulses and provides an output signal directly or proportionally indicative to the number of such pulses received.  
  As used herein a decade switch may be defined as having two or more sections, each having ten times the value of the preceding section and each section being divided into 10 equal parts. Each section has a 10 position selector switch or its equivalent arrangement such that it may be set at any given design value in its range.  
  As used herein gating means may be defined as a circuit or device permitting the selective passage of an input pulse or signal from one unit to another and which is operable on the input of an independent signal to it to either close or open said means to the passage of the first signals.  
  As used herein the indicator may be defined as a read out device for either visual, digital or analog read out of accumulated pulses or pulse signals and may include memory storage and recording means as well as optical discharge tubes showing the read out value.  
  Various changes, modifications and embodiments have been suggested. Others will be apparent to those skilled in the art. Accordingly, it is intended that the present disclosure be taken as illustrative only and not limiting of the scope of the invention.  
 What is claimed is:  
  l. A system for measuring and indicating the twist factor of spun yarn formed in an open end spinning unit having feed means for delivering fibrous material. a rotary twisting means for spinning the fibers into a yarn. and a rotary withdrawing means for taking up the yarn comprising. first detector means located at said twist means for sensing the revolution of said twist means and providing an output having a value proportional to the number of revolutions thereof a second detecting means located at said withdrawing means for sensing the revolution of the withdrawing means and providing an output having a value proportional to the number of revolutions thereof. said first detecting means being connected to the input of a first counter, a gate means 0nd counter includes a decade number switch.  
  3. The system according to claim 1 wherein said detectors are contactless.  
  4. The system according to claim 3 wherein said detectors are photoelectric cells and said withdrawing means and said twisting means are provided with at least one optical marking.