US3109204A - Device for controlling the uniformity of textile yarns - Google Patents

Description

- Nov. 5, 1963 A. LINNERT ETAL Q DEVICE FOR CONTROLLING THE UNIFORMITY OF TEXTILE YARNS- Filed Oct. 5, 1959 4 Sheets-Sheet 1 INVENTORS; A THUR Lllvwmr IMRfll-D (ATM/V6 BY ALBE T ram/w 055m Nov. 5, 1963 DEVICE FOR CONTROLLING THE UNIFORMITY Filed Oct. 5, 1959 A. LINNERT ETAL OF TEXTILE YARNS 4 Sheets-Sheet 2 Nov. 5, 1963 RT E I I 3,109,204 W DEVICE FOR CONTROLLING THE ,UNIFORMITY QF TEXTILE YARNS Filed Oct. 5, 1959 '4 Sheets-Sheet 3 INVENTORS:

ART/10R L uwvmr lmkvz o [ATl/AIO uasar zen/44w MBA/ 4 ATTO NEY NOV-Q .1963 A. LINNERT ETAL 3,109,

DEVICE FOR CONTROLLING THE UNIFORMITY OF TEXTILE YARNS 4 Sheets-Sheet 4 Filed Oct. 5. 1959 INVENTORS: ARTHUR LINNERT HAROLD CATLING ALBERT EDWARD DE BARR fluctuations in the property to be controlled,

United States Patent O 3,109,294 DEVICE FOR CGNTRGLLING THE UNIFORMITY F TEXTILE YARNS Arthur Linnert, 43 Clyde Road, West Didsbury, Manchester, England, Harold Gatling, 57 Kingston Road, Didsbury, Manchester, England, and Albert Edward De Barr, 11 Dayies Ford Road, Cheadle, England Filed Get. 5, 1959, Ser. No. 344,425 Claims priority, application Great Britain Oct. 7, 1958 Claims. (Cl. 19-241) This invention concerns the spinning of textile yarns from fibrous materials, and is applicable to spinning processes and machines, especially drafting and lap-forming formity of the material issuing from such a machine to be achieved.

According to the present invention a control device in, or for use in, a process for spinning textile yarns :from fibrous materials in which a property of the material is to be modified by a machine at a given treatment stage, comprises means for measuring said property, directly or indirectly, after processing of the material has taken place in the machine, so as to detect fluctuations, which are long-term relative to the processing time, in said property at that stage and adapted, on detecting such fluctuations, to control the action of the machine to give substantial constancy of said property. The device therefore operates on the feed-back or closed loop principle and one advantage of this is that it takes account of fluctuations in the property which occur after the material has en.- tered the machine and before the stage at which the measurement is taken (which fluctuations are ignored by a device which operates in the open-loop system, that is to say, the controlling action thereof is based on a measurement of the regularity of the material fed to the machine and before processing commences, such as a tripod feed regulator, commonly used on a scutcher). Unlike an open-loop device, the closed loop device does not have to be constructed to bring about precise compensatory changes for a given fluctuation in the property of the material to be controlled, because its corrective action will continue until the required value of the propcrty is obtained.

However, a device operating on the closed-loop principle alone must not be sensitive to very short-term in order that the control system shall remain stable.

where the processing time is long compared with the frequencies of the purely short-term fluctuations, such shortterm fluctuations would therefore still be present and may Well be a serious problem. Preferably therefore, and especially in such machines, the invention is further characterised in that the device includes additional means, being means for measuring said property, directly or indirectly, before processing of the material takes place in the machine, so as to detect relatively short-term fluctuations in said property at that stage, and adapted, on

detecting such fluctuations, to control the action of the machine to compensate therefor. Such a device involving a combination of open loop and closed loop control is also self-correcting in cases where the accuracy of the In machines 33W ,Zdl Patented Nov. 5, 1963 2 open loop part thereof deteriorates. Thus, if the open loop part begins to operate for example, as though too much mate-rial Were passing when in fact the amount passing is correct, the resultant decrease will cause the closed loop part to act in a correcting manner to increase the amount.

The invention will now be described further, by way of example, with reference to control devices for a scutcher, and in the accompanying drawings:

FIGURE 1 is a diagrammatic illustration showing the application of the invention to a scrutcher of one such device;

FIGURE 2 is a diagrammatic illustration of an alternative arrangement;

FIGURE 3 is a diagrammatic'illustration showing the application of the device to a drafting machine; and

FIGURES 4, 5 and 6 are diagrammatic illustrations of various arrangements of the mechanisms for detecting the thickness of the .lap leaving the apparatus.

Referring firstly to FIGURE 1, control of the weight per unit length of the web or lap produced by a scutcher is effected.

The main parts of the scutcher comprise the beater l1, the top cage -12, the bottom cage 13, the calender rollers 1d, 15, 16, 1'7, and the laprollers 18, 1'9. Ootton is fed to the beater 11 by a feed lattice 2i) and 'via a pedal roller 21 operatively associated with a pedal assembly 22 supported by a knife rail 23.

The pedal assembly 22 is connected by a link motion 24 to a lever 25 which is itself pivoted to a nut as. The pedal assembly and link motion are of the conventional type which has been used on scutchers for many years. One end of the lever '25 carries counterweight 27 Whilst the other end carries a link 28 for operating the plunger 29 of a valve 39. The link 28 is riveted at both ends to the lever 25. The valve forms part of a control circuit for a variable speed hydraulic motor 31, the other main elements of the circuit being a pump 32 and a tank 33 for hydraulic fluid. The motor 31 drives the pedal roller 21 through a worm 34 and worm-wheel 35.

Above the top calender roll 14 is disposed a detector 36 sensitive to the vertical position of the roll 14 and adapted, by means of an elective-mechanical system 37 to rotate a shaft 38 carrying a worm 39 in mesh with a Wormwheel 40. The electromechanical system 37 consists of thatas cotton 42 is fed to and passes through the scutcher,

is for example a slow the device is operative to control the regularity of the issuing lap very effectively in the manner now to be described.

Short-term fluctuations in. the thickness of the incoming mass of cotton 42 are'detected by the pedal assembly 22 which causes movement of thelink motion 24, lever 25, link 28, and valve plunger 2?. The arrangement is such that when the thickness increases the responsivemovement of the valve plunge-1' causes the hydraulic motor to slowdown by an amount which results in the rate of feed of ,cottonremaining constant (assuming the relationship between thickness and weight per unit area to be unchanged).

The detector 36 is sensitive to the thickness of the lap passing through the calender roll system, and is arrangedrto cause through associated control means, movement of the lead-screw '41 in response to long-term fluctuation of the thickness of the material. Thus when there increase in the mean thickness of the cotton at the calender rolls the lead-screw 41 turns in such sense as to displace the nut 26 and thus the pivot point of lever 25 in a direction which causes the system for correcting short-term fluctuations to operate about a different datum corresponding to a slower motor speed.

in this manner both short-term and long-term fluctuations are dealt with (except, of course, short-term fluctuations which arise after the pedal roller).

In the modified arrangement of FIGURE 2, like parts to parts in FIGURE 1 have been given the same reference numeral. In this embodiment of the invention the hydraulic motor for controlling the speed of the pedal roller 21 is substituted for a purely mechanical system of speed control based on two opposed cone drums 42, 43. The drum 43 is driven at constant speed by means of a gear transmission 44 from the lowest calender roller 17, whilst the drum 42 is adapted to drive the pedal roller 21 through appropriate gears and pulleys and a belt 45. A belt 46 transmits the drive from drum .3 to drum 42. The lever 25, when it moves in response to a fluctuation in the thickness of the material at the pedal roller 2-1, is arranged to adjust the belt 46 in the appropriate direction to cause a compensatory speed adjustment of the pedal roller speed. In the same manner as the previous embodiment, long-term fluctuations at the calender rolls will cause a correcting adjustment of the pivot point of the lever 25 by movement of lead screw 41 and therefore nut 26.

Reference has been made to a detector 36 forming part of the closed loop controlling means. In one arrangement any vertical movement of the uppermost calender roll 14 caused by variation in thickness of the lap is detected at some point along the roll 14, preferably at the centre thereof, and transmitted to one or both ends of the roll l t where the measuring means can more conveniently be accommodated. For example, as shown in FIGURE 4 a bar 137 is rotatably mounted above the roll -14, and carries a feeler 136 which contacts the highest point of the roll 14- at the chosen point along its length. Movement of the feeler 136 in response to ventical movement of the roll 14 causes the bar 137 to rotate, and at one end of the bar is fitted an arm 138, which again converts this rotational movement into translatory movement. One end of the arm 138 extends relative to the bar 137 in a direction opposite to the direction in which the feeler 136 extends and the movement of this end is conveyed to a transducer 139', which is operative to effect the necessary control. The other end of the arm 13-8 relative to its pivot point extends in the same di rection as the feeler 136 and a stop 140 is provided to limit excess movement of this end of the arm 138 towards the transducer 13% which might otherwise damage it. Clearly excess movement of this end of the arm 138 in the other direction must be unrestricted, so that gross variations in the thickness of the lap can be accepted without damage to the transducer 139.

The arrangement just described involves only one measurement across the width of the machine, and since variations in thickness may well take place across the width of the lap, an arrangement which makes a number of measurements at spaced points across the machine, and overlaps them to give a control which responds to the mean transverse thickness, is preferred. In one such arrangement, shown in FIGURE 5, a number of special rollers 141 is provided each of which bears against the lap 42 as it passes in front of one of the calender rollers 15 at each measurement point. Each roller 141 is :mounted at one end of a bell-crank lever 142 between a pair of arms 142a, arm 14% of which at t e other end, in response to variations in lap thickness at the measuring point concerned, transmits movement to a transducer 143 mounted on stationary member 150 and means 144 is provided for combining and averaging the signals from all the transducers and operating the control means ac cordingly. 7

In nother c n enient arrangement, shown in FIGURE 6, a lever 145, pivoted at one end, extends over each hearing cap 146 of the upper calender roller 14. The other end operates a transducer 147 as in the previously described arrangements. In this case vertical movement of the calender roller 14 in response to variations in the lap thickness cause the lever 145 to pivot in a corresponding manner, and the movement is transmitted to the transducer 147. Summation and averaging means are incorporated so that the signal to the control means is equivalent to that which would be given by a measurement taken at the centre of the roll. This is a useful arrangement because it avoids the use of a detection member at the centre, or anywhere across the width of the roller. Micrometer means 149 will usually be associated with each lever for setting purposes.

The invention is, of course, applicable to machines other than scutchers. FIGURE 3 shows a drafting machine. Back rollers 47, 48 are driven at a fixed speed by a conventional drive (not shown) and front rollers 49, 5%) are driven from the back rollers 47, 48 by gears 51, 52, 53, 54, frusto- conical pulleys 55, 56 and belt 57. The fibrous material 58 is fed to the back rollers 47, 48 through measuring rollers 5h, 60 the upper such roller 59 being sensitive to the thickness of the fed material. The upper front roller 49 is likewise sensitive to the thickness of the material issuing from the machine.

A transducer 61 is mounted in contact with roller 59 and provides a signal through a time delay unit 62 and amplifier 63 for controlling the position of an actuator 64 in the manner and for the purpose described here-inafter.

A transducer 65 is mounted in contact with roller 49 and provides a signal through a control unit 66 associated with a reference level 67 and an integrating mechanism 68. The belt 57 is shiftable by a belt for-k 69 mounted on the end of a lever 70 pivoted at its centre point to a linkage 73, 74 and pivotably attached by its other end to a nut 71. The nut is mounted on a lead-screw 72 which is axially fixed and which is rotated by the integrating mechanism 68. To the centre region of the lever 70 is connected the linkage 73, 74, operated by the actuator 64.

In operation, closed loop control of long-term fluctuations is achieved due to the sensitivity of the transducer 65 to the thickness of the issuing material. The control unit 66 gives an output signal representing the difference between reference level 67 and the signal from the transducer 65'. This signal passes to the integrating actuator which has a velocity proportional to this error signal and the position of the nut 71 in the lead screw 72 is adapted to cause a compensatory pivotal movementof lever 70 and thus belt 57 to increase or decrease the speed of the front rollers 49, 50 as required. .Open loop control ofshort-term fluctuations is achieved due to the sensitivity of transducer 61 to thickness of the fed ma terial. The time delay unit 62 gives an output signal to the amplifier 63 and the amplifier 63 passes this on to the position control actuator 64. This actuator 64 is adapted to cause the linkage 73, 74 to move the lever 70 to cause a correcting variation in the speed of the front rollers 49, St} at the appropriate time to correct for the short-term irregularities.

;We claim:

1. In a machine which processes a fibrous material in order to modify a property thereof, a feed roller, a first sensing means so located as to measure said property of the material before it is processed, an adjustable control means including a lever responsive to said first sensing means for varying the speed of said feed roller by virtue of its movement about a fulcrum thereof, a second sensing means so located as to measure said property of the material after it is processed, and means responsive to said second sensing means for altering the position of the fulcrum of said lever.

2. In a machine which processes a fibrous material in order to modify a property thereof, the elements described 5 in claim 1 wherein said first sensing means is a pedal assembly adjacent to said feed roller, and said feed roller is driven by an hydraulic motor forming part of an hydraulic circuit, said control means including a valve in said hydraulic circuit capable of altering the speed of said motor.

3. In a machine, which processes a fibrous material in order to modify a property thereof, the elements described in claim 2 wherein said second sensing means is a transducer, and said responsive means is an electromechanical system associated with said transducer.

4. In a machine which processes a fibrous material in order to modify a property thereof, the elements described in claim 1 wherein said first sensing means is a pedal assembly adjacent to said feed roller, and said feed roller is driven by a transmission including a pair of opposed cone drums connected by a belt, said lever engaging said belt and adapted to move the belt longitudinally of said drums in order to alter the speed of said feed roller.

5. In a machine which processes a fibrous material in order to modify a property thereof a feed roller system, a first transducer associated therewith and so located as to measure said property of the material before it is processed, an adjustable control means including a lever responsive to said first transducer for varying the processing action of the machine by virtue of its movement about a fulcrum thereof, a second transducer so located as to measure said property of the material after it is processed, and means responsive to said second transducer for altering the position of said fulcrum, said control means including a pair of opposed cone drums connected by a belt, and said lever being in engagement with said belt and adapted to move the belt longitudinally of said drums.

References Cited in the file of this patent UNITED STATES PATENTS 2,028,698 Curley et 'al Jan. 21, 1936 2,205,304 Mutter June 18, 1940 2,682,144 Hare June 29, 1954 2,770,843 Strother Nov. 20, 1956 2,805,449 Martin Sept. 10, 1957 2,950,508 Locher Aug. 30, 196 0 2,981,986 Neil May 2, 1961 FOREIGN PATENTS 212,094 Australia Oct. 24, 1957 720,200 Germany Apr. 28, 1942

Claims (1)

1. IN A MACHINE WHICH PROCESSES A FIBROUS MATERIAL IN ORDER TO MODIFY A PROPERTY THEREOF, A FEED ROLLER, A FIRST SENSING MEANS SO LOCATED AS TO MEASURE SAID PROPERTY OF THE MATERIAL BEFORE IT IS PROCESSED, AN ADJUSTABLE CONTROL MEANS INCLUDING A LEVER RESPONSIVE TO SAID FIRST SENSING MEANS FOR VARYING THE SPEED OF SAID FEED ROLLER BY VIRTUE OF ITS MOVEMENT ABOUT A FULCRUM THEREOF, A SECOND SENSING MEANS SO LOCATED AS TO MEASURE SAID PROPERTY OF THE MATERIAL AFTER IT IS PROCESSED, AND MEANS RESPONSIVE TO SAID SECOND SENSING MEANS FOR ALTERING THE POSITION OF THE FULCRUM OF SAID LEVER.

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