US2565500A

US2565500A - Control of filamentary material

Info

Publication number: US2565500A
Application number: US766738A
Authority: US
Inventors: Jr Robert M Ingham
Original assignee: Milliken Research Corp
Current assignee: Milliken Research Corp
Priority date: 1947-08-06
Filing date: 1947-08-06
Publication date: 1951-08-28
Anticipated expiration: 1968-08-28

Description

Aug; 28, 1951 Filed Aug. 6, 1947 R. M. INGHAM, JR

CONTROL OF FILAMENTARY MATERIAL 2 Sheets-Sheet 1 TO METERING CIRCUI INVENTOR ROBE RT M. INGHAM ORNEY 195l R. M. INGHAM, JR 2,565,500

CONTROL OF FILAMENTARY MATERIAL Filed Aug. 6, 1947 2 Sheets-Sheet 2 M 9,3 INVENTOR ROBERT M. INGHAM Q ORNEY Patented Aug. 28, 1951 CONTROL OF FILAMENTARY MATERIAL Robert M. Ingham, Jr., Clemson, S. 0., assignor to Deering Milliken Research Trust, New York, N. Y., a nonprofit trust of New York Application August 6', 1947, Serial No. 766,738

6 Claims.

The present invention relates to the textile art and more particularly tothe manufacture of yarn and comprises a novel method of, and means for, detecting and signalizing unwanted irregularities in yarn characteristics before the yarn is woven or knitted into fabric.

When a yarn, for example worsted yarn, has a wad orknot of fibers, called a slub, therein, or when a relatively extended length of yarn, say a foot or more, has a relatively large diameter as compared to the average diameter of the yarn, fabric woven or knitted from such yarn is unsatisfactory, and it is important, therefore, that such irregularities be detected and preferably removed from the yarn before production of fabric. With the high speed machinery used at present in textile mills, in the spinning and winding operations, it is impractical, if not impossible, for such defects or irregularities to be detected by visual inspection. Certain mechanical devices, called slub catchers, which have been developed and used in the industry. will detect relatively hard and incompressible slubs. One such known device is a comb between the teeth of which the yarn passes andat which the yarn breaks when a slub wider than the spacing between teeth is caught thereby. Another such known device is a pivoted knife blade which is mounted above a grooved surface; the yarn passing between the blade and surface and slubs on the yarn engaging the blade to swing it into yarn cutting position. Neither of these known devices is effective to detect and to eliminate compressible slubs, such as are apt to occur in worsted or woolen yarns, and neither is effective to cut the yarn when a predetermined length of the yarn is of greater diameter than the desired diameter but less than the diameter of a slu The device of the present invention, on the other hand, detects soit or compressible slubs as well as hard slubs and may be arranged to detect also lengths of yarn of a predetermined diameter less than that of detected slubs but greater than that desired for such length of yarn. In the preferred embodiments of the invention (Figs. 3, 4, the device operates to cut the yarn in the event of failure of any part of the controlling circuit, thereby insuring against imperfect operation of the device and consequent possibility of defective yarn being passed thereby.

The term slub, as used herein, is intended to mean a relatively short length of yarn of excessive diameter, whereas the termfheavy section is intended to mean a relatively long section of yarn of diam ter les than a slub but for the yarn under invention and comprising a photoelectric type of yarn diameter meter arranged for detecting and eliminating slubs in yarn;

Fig. 1a is a diagram showing the device of Fig. 1 arranged for counting slubs in a given length of yarn; v

Figs. 2 and 3 are diagrams similar to Fig. 1 but illustrating a capacitative type and pneumatic type, respectively, of yarn diameter meters;

Fig. 4 is a diagram illustrating the invention as embodied in a device arranged for detection of slubs and of sections of heavy yarn; and

Fig. 5 is a diagram illustrating the invention as embodied in a device arranged for detection of weak sections, that is, sections of less diameter than the desired diameter.

In Fig. l, yarn, the slubs in which are to be detected and eliminated, is indicated at 2'. The

.yarn is moved in the direction of the arrow by at a relatively high rate of speed. In accordance with the invention, the yarn in its travel passes through a yarn diameter responsive device and then beneath a normally inactive cutting means. In the embodiment of the invention illustrated in Fig. 1, the meter or yarn diameter responsive device comprises a pair of balanced photocells 4 and 6 connected in series across a center grounded battery 8, and each positioned to receive light from a source It. A lens and aperture system H is positioned between the light source Ill and the cell 4, and a light valve It is positioned between the source Ill and cell 6. The yarn 2 in its travel passes between the lens system l2 and cell 4 so that the amount of light reaching the cell varies in accordance with variatromagnet or relay 24 and a manually operable switch 25. Relay 24, when energized, attracts a pivoted armature 26 which is normally held in retracted position by a spring 28. Armature 26 has a cutting edge along its free side which engages and cuts the yarn 2'during movement of the armature to attracted position. A suitable flat or slightly curved surface 30 is positioned beneath the knife edged armature 26' for passage and guidance of the yarn thereover.

With the above described circuit, the elements may be so adjusted that the currents through the photoceils'4 and 6 are equal when the yarn is of the desired diameter. Under these conditions, the first grid of tube I8 is at cathode potential as the potential difference across resistor i6 is zero. With increasing diameter of yarn, decreasing current flows through cell 4 and hence, the potential on the first grid of tube I8 become positive with respect to the cathode. When this potential becomes sufliciently high to trigger" tube [3, switch being closed, relay 24 will become energized to move the armature 26 into yarn cutting position. Thus, so long as the yarn diameter remains less than that which causes tube I8 to pass current, the armature 26 remains in retracted position, but when yarn of such diameter, or of greater diameter, passes cell 4, tube ill will pass current and energize relay 24. After the yarn is cut the operator momentarily opens switch 25 to deenergize tube Ill. The apparatus may be adjusted for detection and consequent cutting of yarn of any desired minimum diameter by adjustment of the circuit elements, as for example, of resistor l6 or of battery 20,

Instead of severing the yarn each time a slub is detected, that is, each time the tube I8 is triggered, the circuit could be arranged for providing a count of the total number of slubs in a given length of yarn. For this purpose, as shown in Fig. 1a, a relay 21 in the plate circuit of the tube l8 actuates a mechanical counter 29 each time the tube is triggered; the circuit of the magnet and of tube 18 being opened at contacts 3| following each energization of relay and actuation of the counter. To insure release of the relay and subsequent closure of contacts 3| a condenser 33 is provided. At times, yarn having not more than a predetermined number of slubs in a given length, is specified for a particular purpose. By means of the circuit of Fig. la, the suitability of a given yarn for such p se may be readily determined.

In Fig. 2, the yarn metering device comprises a bridge network of resistive elements 32 and 34 and

capacitative elements

36 and 38; alternatin current being supplied to the input terminals 40 of the bridge network from any suitable source (not shown). The yarn 2 passes between the plate electrodes of element 36 so as to vary the capacity thereof with changes in diameter. and element 38 is preferably adjustable, as indicated, for balance of the network. The input circuit of a gas tube Ila is connected across the bridge network so as to have the potential on its grid increased with'increase in diameter of the yarn. Normally deenergized magnet 24 is in the plate circuit of tube Ila and operates, when energized, to attract armature 26 into yarn cutting position. Thus. as in Fig. 1, when the yarn diameter equals or exceeds a predetermined value, the-gas tube will break down and pass current and the yarn will be severed. In Fig. 2, the tube l8a controlling the relay 24 is shown as a three element tube,

4 but a four element tube, such as tube i8 of Fig. 1, could as well be used.

The slub catcher of Fig. 3 differs from those of I Figs. 1 and 2 in that pneumatic, rather than electrical, means are mployed for determining yarn diameters, and in that the magnet 24a is normally energized and is deenergized when a slub is detected. The meter comprises a casing or enclosure 42, the interior of which is divided into two chambers 44 and 46 by a diaphragm or piston 48 to which a rod 50 is attached; the rod 50 extending through an aperture or sleeve in one wall of the casing 42. Air or other fluid under pressure is delivered from any suitable source (not shown) through restricted orifices 43 into the chambers 44 and 46 and bleeds to the atmosphere from chamber, 46 through an adjustable orifice 52 and by leakage along the rod 50. A tube 54 through which the yarn 2 passes, is connected to chamber 44 to permit bleeding of air therefrom to the atmosphere. Rod 50 is connected to a pivoted switch arm 56 controlling the circuit of relay 24a. The movable end of arm 56 contacts an arcuate member 58. Member 58 has a conducting portion 58a and a non-conducting portion 58b, the conducting portion being connected to the winding of relay 24a. A battery 22a, or other suitable source of power, is connected to the other end of the winding of relay 24a and to the switch arm 56. Relay 24a, when energized, holds pivoted armature 26a out of yarn cutting position in opposition to a spring 28a. With the above described arrangement, the pressure in chamber 44 will vary with the diameter of the yarn passing through tube 54, increasing with increas in yarn diameter and decreasing with decrease in yarn diameter. Consequently, diaphragm 48 and rod 50 will move back and forth in accordance with yarn diameter variations, but movement of rod 56 will not deenergize relay 2411 so long as the diameter variations are insuflicient to move arm 56 beyond the conducting portion 58a of contact member 58. When the diameter of the yarn exceeds such value, switch arm 56 is moved to contact the insulating portion-58b of member 58, thereby openratus may be readily effected by adjustment of the valve 52, of the leverage of the switch arm, of the inlet fluid pressure or of the length or position of the conducting and insulating sections.

The description so far given has been of embodiments of the invention suitable for use when detection and elimination of slubs only is desired. If, in addition to detection and elimination of slubs, it is desired to detect and eliminate relatively long sections of oversized yarn, termed heavy sections," the arrangement of Fig. 4 may be employed. As in Fig. 3, the relay 24a is normally energized to hold the armature 26a out of yarn cutting position. The relay 24a, as shown, is in the plate circuit of a triode 60, which may be a 6J5 and which normally, that is when the yarn 2 has the desired characteristics, passes sufficient current to maintain the relay 24a energized. A photocell 4a is positioned, like photocell 4 of Fig. 1, to respond to variations in diameter of the yarn 2. The anode of cell 4a is connected to a suitable source of energy, indicated as B+, and the cathode of the cell is connected through a high resistance 62 and a low resistance 63 in the cathode circuit of tube 66 to the negative terminal oi the source, symbolized as ground. A second triode 64, which may also be a 6J5. has its grid connected to the cathode of the cell 4a through a condenser 88 and to ground through an integrating circuit including a resistor 68 and bridging capacity 10. The term integrating" is here used to mean a summing up or adding circuit. The cathode of tube 64 is grounded through a biasing resistor I2, and the plate of tube 64 is connected to 3+ through a resistor 14. The anode of tube 64 is connected to ground through a capacity 18 and resistor 18. Th grid of tube 88 is connec to the ungrounded end of resistor 18.

The characteristics of the above described circuit are such that the gain is high for low frequencies, corresponding to long period diameter variations of the yarn and low for high frequencies corresponding to slubs in the yarn.

Thus, when there is a large but relatively transient drop in current through the photoc ll, as would occur when a slub intercepts the light to the cell, or, when there is a drop in photocell current of less magnitude but of relatively longer duration, such as would be caused by a, stretch of heavy yarn, the current through tube 64 is decreased. As a result of such decrease in current, condenser 78 is rapidly charged through the gridcathode circuit of tube 68 and then slowly discharged through the high resistance driving the grid of tube 88 negative with consequent deenergization of the relay 24a and severing of the yarn 2. Thus, because of the higher gain of the amplifier circuit at low frequencies, relatively long stretches of yarn of a diameter that would not releas the relay if of short duration, will be detected. The size of slub to be detected and the I increases due to a decrease in the yarn diameter,

the current through tube 32 likewise increases, tending to decrease the potential applied to the control grid of tube 98. If such increase in photorelation between the length of yarn necessary to minimum diameter and length of heavy or oversized yarn to be detected, are, of course, a matter of choice, and the circuit constants will be selected accordingly.

In the embodiments of the invention so far described, the occurrence of slubs, or of slubs and heavy sections of yarn, has initiated operation of the yarn signifying mechanism. In accordance with the invention the presence of undersized sections of yarn can also be readily detected, if desired. Any one of the devices of Figs. 1 to 4 could be arranged for such detection of undersized yarn by change in th yarn diameter metering device so as to create a control signal varying inversely, instead of directly, with the yarn diameter, as will be apparent to those skilled in the art. Fig. 5 shows a metering circuit of this type which operates to control the yarn severing mechanism whenever a short length of very small diameter yarn, or a longer length of less small diameter yarn passes between the photocell la and light source l8. Cell has its anode connected to the source of high potential, indicated as 13+ and its cathode connected through a resistor 88 with the negative terminal of the source, indicated as ground. The grid of a triode 82, which may be a 6J5, is connected to th cathode of photocell 4a through a condenser 84 and to ground through a resistor 86. The anode of tube 82 is connected to 3+ through a resistor 81, and to ground through a capacity 88 and an integrating circuit inseries therewith; the integrating circuit comprising series connected resistors 90 and 82 and a capacity 88 bridging resistor 92. The anode of tube 8 2 is also connected to ground through a high frequency attenuating capacity 98. The grid of a second triode 98, which may also be a 6J5, is connected to an adjustable tap on resistor 92. The winding of relay 24a, controlling the knife edged armature 28a, is in the plate circuit of tube 98. With the above described circuit, when the current through photocell 4a cause deenergization of the relay for any particular diameter of the yarn depending, of course. upon the rate of travel of the yarn-and upon the constants of the amplifier circuit.

The invention has now been described with reference to several embodiments thereof. In each embodiment of the invention, the means controlled by the detector has been indicated as a pivoted knife operated upon energization or deenergization of a relay, or as. a mechanical counter, but obviously, other means for signifying the occurrence of yarn diameter variations could be employed. Severing the yarn, as herein described, eliminates the unwanted portion from one end only of the yarn. The attendant or operator must then cut the unwanted portion from the other end and tie the ends together. Thus, the detection and identification of location of diameter variations could be efiected without actual severance of the yarn by the device. For example, the device could mark the yarn, or could sound a signal to attract the operator or could apply a brake or otherwise stop the machine which is causing the travel of the yarn. Also, various other types of yarn diameter responsive means could be employed either as part of a simple slub catcher, such as the devices of Figs. 1, 2 and 3,. or as part of a combined slub catcher and heavy yarn detector and identifier such as the device of Fig. 4 or the detector of short and long sections of weak or thin yarn such as the device of Fig.5. Broadly, the invention may be said to comprise a diameter responsive means through or by which filamentary material may be moved and which creates a control signal, and a device controlled by the signal for signifying diameter variations of the material.

The device of the present invention, as heretofore indicated, may be located at any one of several positions in a mill and hence does not require any additional rewinding operation although, of course, such additional stage could be employed if desired. The term slub, as used in the appended claims, is intended to mean a relatively short length of yarn of excessive diameter, whereas the term heavy section in the claims is intended to mean a relatively long section of yarn of diameter less than a slub but greater, than that normal for the yarn under consideration. Preferably, the device would be used in an early stage of yarn production, as for example, between the draft rolls and yarn guide of a yarn spinning mechanism. It could also be used at a still earlier stage, as for example, during the production of roving, or between the stages of a two stage tow to yarn process. The invention, while particularly applicable to yarns produced from staple fibers, may be advantageously employed for detecting excessive diameter sections of filamentary material which comprises continuously measuring the diameter of the with and signifying by the material the location where the departure of the created signal from normal exceeds a predetermined value for a short period of time and exceeds a normal value but is less than the first named departure from the normal value for a longer period of time.

2. A device for detecting diameter variations in textile filamentary material which comprises means positioned adjacent the path of travel of the material and adapted to create a control signal varying in accordance with variations in the diameter of the material, means for integrating said signal over a period of time, and signal means con-trolled by said integrating means whereby short term large departures from normal and long term lesser departures from normal of the diameter of the filamentary material may be signalized.

3. The device according to claim 2 wherein said signal means operates to sever the filamentary material.

4. A slub catcher for textile filamentary ma terial comprising a photoelectric cell positioned adjacent the path of travel of the material for transmitting a current varying with the diameter 8 of the material, an integrating circuit connected to said photoelectric cell for convering current transmitted by said cell into a control signal, a

. material to create a control signal varying therenormally inoperative material severing means and means controlled by said control signal for rendering said severing means operative to sever the material upon occurrence of either short term slubs or long term heavy sections of the material of diameter less that of 1 the slubs.

5. The slub catcher according to claim 4 wherein said last mentioned means includes a gas tube and said control signal is applied to a grid thereof.

6. The slub catcher according to claim 4 including normally energized electromagnetic means for holding said severing means in inoperative position, the last mentioned means of said claim operating to 'deenergize said electromagnetic means to eifect severing when said signal exceeds a predetermined value.

ROBERT M. INGHAM, JR.

REFERENCES CITED -The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,915,204 Scheikli June 20, 1933 2,107,926 Asmussen Feb. 8, 1938 2,199,396 Dubilier May 7, 1940 2,438,365 Hepp Mar. 23, 1948