US2361217A - Apparatus for producing highly uniform sliver - Google Patents

Description

CROSS REFERENCE Examine? 250-201 AU 252 'Ex FIP8212 XR 2,361,217

Oct. 24, 1944. Ew 2,361,217

APPARATUS FOR PRODUCING HIGHLY UNIFORM SLIVER Filed Jan. 2, 1941 1 w a r I a W I v M q k; o :0; adj o, E il Q X ,2 a

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ifv-FfF-fi Q--::=xa as! permitted the draft rolls to work with greater Patented Oct. 24, 1944 UNITED STATES PATENT OFFICE Arthur 1. Lewis, Fairhaven, Mass., assignor to United States Rubber Company, New York, N. Y., a corporation of New Jersey Application January 2, 1941, Serial No. 372,762

4 Claims. 401. 19-70) This invention relates to yarn production.

'The object of the invention is to produce a yam of more uniform size and strength than has been heretofore possible by producing a highly uniform sliver in a simple, practical and eco- 5 nomical manner.

A further object of the invention is to provide tion, thick edges and the usual departures from the uniform web seem to have no great bearing from the ratio of weight to light passed, when integrated over full width of the web.

In accordance with the present invention, the variations in the amount of light transmitted through a web or sliver being subjected to draftnovel and eflicient apparatus for producing the ing, are utilized to control the speed of a draftpresent superior sliver. ing roll to which the web is fed, to the end that In the accompanying drawing, the single figan increased draft may be exerted upon the heavure is a perspective view illustrating diagramier portions of the web and less draft upon the 'r'natically the apparatus and control mechanism lighter portions of the web. While the invenof a preferred embodiment of the invention. tion may be applied at various stages in prepar- Prior to the present invention, as far as I am ing the yarn wherever a drafting operation is aware, no one has succeeded in commercially being performed, nevertheless, it is preferred toproducing a finished yarn of non-continuous fibers that does not vary in size and strength between wide limits. It is common to find in draw frame and prior to the passage thereof good yarns a size variation of as much as sixty through the last pair of draw rolls. In pracpercent (60%) in the same hank, when the same '20 tice, a source of light may be disposed upon one 'is checked in inch to inch measurement. Simi side of the web or sliver and in a position to larly, strength tests of the hank show large varcause the light beam to be transmitted thereiations from average, varying in many instances through, and a photo-electric cell or other light fifty percent (50%) from the average. sensitive device may be disposed upon the oppo- The variations in uniformity and strength in site side of the web in a position to be acted the finished yarn are brought about by the inaupon by the lighttransmitted through the web. bility to draft evenly, using prior methods and The variations in the amount of light thus prior apparatus, and accordingly, it i the partransmitted through the web as heavier and ticular aim of the present invention to provide lighter p i e f Pass through the light 'a novel apparatus by which drafting operations beam cause proportionate variations in the curmay be conducted and regulated in an eiiicient, rent passing through the photo-electric cell and rapid and practical manner to exert more draftthese variations are, in accordance with the presing upon the thicker, heavier portions of a web ent invention, utilized to control the speed of or sliver and less drafting upon the lighter porthe last draw rolls to the end that increased tions, to the end that in the finished sliver, a drafting may be exerted upon the heavier por- 'minimum of variations in size and strength may ,tions and less drafting upon the lighter portions be present. I a of the web or silver, it being understood that a In studying short pieces of cotton sliver under web or sliver of suilicient weight is fed through the microscope, it has been noted that in the the draw frame to produce a yarn of the desired lightest samples, the fibers were nearly parallel, 40 weight. substantially free of immature and neppy cotton Referring now to the drawing, I have illusand the character of the fibers consequently trated a sufficient portion of a conventional draw frame to enable the present invention to be uneffect, producing a section of reduced weight. derstood. The drafting is accomplished by the On the contrary, the heavier weight samples passageof the web or sliver 8 so that it advances were made up of a large portion of curly neppy to the right through successive sets of draw rolls fibers with long streamers from them which Ill and in accordance with the present invention, tended to nep. This reduced the ability to acthe last pair of draw rolls I2, is arranged to be cept the action of the draft rolls, and as a result, driven by a variable speed motor l4, herein shown a heavier weight section was produced. It has as connected by spiral gears I6, I 8 to the driving been found by careful laboratory experiments shaft 20 for the last pair of draw rolls. The last that the amount of light passing through a web pai of draw rolls I2 is driven independently of or silver and particularly in the condition in the other pairs of draw rolls l0 and at various which it exists on reaching the final draft, is subspeeds relative thereto by the small motor Hi. stantially proportional to its weight, the diifrac- The remaining draw rolls ill may and preferably expose the web to the action of a light beam during the passage of the web through the usual will be of usual construction and driven in the usual manner; that is the back rolls l which first receive the sliver are driven at a constant speed, and the next pair of rolls are driven at a somewhat faster surface speed, while the pair of rolls l0 next to the final drafting rolls l2 are driven at a still higher surface speed. All three Pairs of r lls l0 may. be. operated by the usual. gears, notshown, andthey are all driven through the gearing connection shown and designated by 22. The right hand gea 22 is driven at a con-- stant speed by means, not shown, when the clutch 2| is manually shifted to connect the gear 22 to the source of power.

The arrangement is such that the sliver successively attenuated or drafted. by the actiom of the three pairs of rolls Ill as usual heretofore. but the speed of the final drafting rolls I2 is varied by the motor l4 to vary the drafting action of this pair of rolls upon the thicker. andi thinner portions, so that the gauge of the thick portions will be reduced sufficiently to form a highly uniform sliver which issues from the rolls l2;

The apparatus is provided with mechanism forcontrolling the speed of the drive for the final drafting rolls I2 herein shown as comprising a. photo-electric cell 24 disposed on one sideof the web or sliver 8 and the light source-26 on theother side. The photo-electric cell 24 and light source 2$- are preferably disposed so as to pass the light beam through the web just prior to the operation of the final draft so that variations in thelight thus transmitted through the web- 8 maybe utilized to .control and regulate the speed of the finaldrafting operation. The usual reflectors and lenses (not shown for the photoelectric cell are provided. Thus, when the web is heavier than the normal weight desired, less light will pass through the web and the speed of the final draft rolls is increased to thin out the heavy portion of the web. or sliver. Conversely, in the event that the material is light in weight more light will pass through the web resulting. in-a decrease inthe speed of: rotation oilthe final draft rolls, and exerting. relatively less, but a st ilpositiye draft .on .such portions.

The operation of the motor 44 to effect the desired changein speed of rotation of the final draft rolls." is automatically controlled by means of the. control system illustrated in thesingle figurea The variable speed motor' I4 comprises a direct'current motor having two field windings 3.0, 32.; One .ofthe field windings 3B is energized through lines 345*36 from .a motor generator set indicated generally. at 38' to :drive themotorl4. As herein shown,- alternating current is suppliedto the.- motor. generator set through conductors- 42from the main supply lines 44, 46. The second field .winding32 is arranged to increase or decrease the speed of rotation of the motor 44' in accordance with the variation in the light passing through the web 8 onto the light sensitive device 24.

The light source 28 is indicated as -an incandescent lamp suitably mounted above the web and may be supplied with energy from a suitable source such as fromthe main supply lines 44; 46-through conductors 48, 50-. The circuit to the second field winding 32 includes the leads 52, 54 from the conductors 40, 42 connected to the. main supply line, and a thermionic valve 56 such as a Thyratron tube having an anode 58, cathode 60,; agrid element 62 and a heater 64. The Thyratron LMUDD U muwt vide pulsating direct current to the second field winding 32 in known manner. The heating element 64 in the tube may be supplied with energy from the main supply lines 44, 46 through conductors 66, 68, a transformer 10 and conductors 12, 14, as clearly illustrated in the drawing.

The photo-electric cell 24 is connected to the direct current. leads I6, 18 from the motor generator set 38 and the circuit includes leads 19, 8| from a voltage divider 80 arranged to provide suitable polarity and voltage, the latter also being connected to. the cathode 60 through line 82. In operation, the photo-electric current traverses the resistance 84, and as is well-known, the grid polli; tential of the-thermionic valve is changed to vary tube operates as a rectifier and amplifier to pro: 7.6

the amount of. energy permittedito pass through the tube 56 to the second field,winding 32 of the motor l4 thus controlling the speed thereof as described.

From the description thus far it will be observed that .by the present invention the excessive variations in strength andsize which have heretofore characterizedthe commercial yarns, may

be. substantially reduced and inasmuch as most yarn is commercially sold on a basis of strength and fineness or uniformity tests, it will be apparent that the commercial value of a yarn may be substantially increased. The present apparatus is rapid in operation to efl'ect the correction in the sliver being subjected to the drafting operation before the silver has passed through the last drafting rolls, thus enabling maximum correction to be made.

The term sliver as used in the specification and claimsis to be construed as meaning a web of greater width than thickness and which is thin enough toperrm't an appreciable amount of light topass therethrough and which is formed of noncontinuous fibers.

While thepreferred apparatus for practicing thepresent invention has been illustrated and described, it will 'be understood that the invention may. be embodied in other forms withinthescope of the followingclaima Having thus.described-the invention, what is claimed is:

1. In apparatusfor theproduction of sliver of.

highly uniform weight, two pairs of drafting rolls spaced apart .andthrough which the web being draftedxiscaused .to pass, asource of light disposed on one side. of .-the.webbetw-een .said pairs of. drafting. rolls, .a light sensitive device disposed upon the oppositesideof .the web and in a posi-- tionto be. acted upon .by thelight transmitted through the web,-and electrical means controlled by. said light .sensitivedevice for increasing and decreasing the s eed of one pair of drafting-rolls nearly. instantaneously through .awide range in accordance with the amountofilight transmitted through thefibrous web.

2. In apparatus fonthe production of sliver of hi hly. uniformweight, pairs of. drafting rolls spaced.;near enough togetherto draft the fibers of aweb, driving mechanism for.the rolls including an independent variable speeddrive for one of the. pairs,.a.sourceof light disposed at one side of. the web between the pairof rolls operated bysald variablespaed driveand another pair of said rolls, a light sensitive device disposed upon the opposite side of. theweblin position -to.be. acted upon by.

the light transmitted throughthe web, and electrical means .controlledbysaid light sensitive device andadapted to control said variable speed drive so as to change its speed nearly instantaneouslythrougha wide range to varyv thedraiting txamme:

of the fibers in accordance with the amount of light transmitted between these particular fibers.

3. In apparatus for the production of a cotton sliver of highly uniform weight, pairs of drafting rolls spaced near enough together to draft the fibers of a cotton web, driving mechanism for the rolls including an independent variable speed motor for one of the pairs, a source of light disposed at one side of the web between the pair of rolls operated by said variable speed motor and another pair of said rolls, a light sensitive device disposed upon the opposite side of the web in position to be acted upon by the light transmitted through the web, and electrical means controlled by said light s sitive device and adapted to control said variab e speed motor so as to change its speed nearly instantaneously through a wide range to vary the drafting of the fibers in accordance with the amount of light transmitted between these particular fibers.

4. In apparatus for the production of a sliver of highly uniform weight, pairs of drafting rolls spaced near enough together to draft the fibers of a web, driving mechanism for the rolls including an independent variable speed drive for one of the pairs, light sensitive electrical scanning means adapted to determine the thickness of the web and positioned to scan the width of the web as it travels between the pair of rolls operated by said variable speed drive and another pair of said rolls, and means actuated by said scanning means and adapted to control said variable speed drive so as to change its speed nearly instantaneously through a wide range to vary the drafting of the fibers in accordance with the thickness of the web formed of these particular fibers as determined by the scanning means.

ARTHUR P. LEWIS.

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