US3166821A - Crimping apparatus - Google Patents

Description

1965 'r. F. FURLONG 3,166,821

CRIMPING APPARATUS Filed Nov. 26, 1962 l8 0 2o 26-" D (Q 24 28 32 INVENTOR T. F FURLONG ATTORNEY United States Patent Ofifice 3,lfifi,82l Patented Jan. 26, 1965 3,166,321 (IRIMPING APRARATUS Thomas F. Furlong, Greenville, S.C., assignor to Monsanto Company, a corporation of Delaware Filed Nov. 26, 1962, Ser. No. 240,fitl1 4 Claims. (Cl. 28-1} This invention relates to an improved method and apparatus for treating filamentary materials and more particularly to an improved method and apparatus for treating continuous filamentary material in such a way that its surface characteristics are modified so as to give such material increased mass or bulk per unit length, resulting in an enhanced hand and appearance.

A substantial portion of the textile industry is at present directed towards the preparation and production of yarn and fabric form synthetic filaments and fibers such as those formed from acrylonitrile and polyester polymers and the like. These synthetic filaments have a number of highly desirable characteristics, such as low cost, long wear, high modulus, and the like. However, due to the synthetic nature and their surface characteristics, certain desirable properties common to the natural fibers, such as Wool and cotton, are not present in these synthetic filaments. As an instance, the fibers of wool in their natural form contain a plurality of crimps consisting of waves which are approximately sinusoidal in form with the number of crimps per inch inthe individual fibers varying widely with the different grades ofwool. It has been determined that these crimps are primarily responsible for the softer feel and warmth in wool by virtue of the tendency of the crimps to hold the individual fibers in the wool yarn apart. Furthermore, the peculiar elastic qualities of wool are thought to stem in some degree from these crimps, as when the fibers are stretched, the crimps are more or less straightened and in the straightened condition they have a spring like tension which tends to return to the original wave conformation of the crir'nped fiber. 3

Many methods and devices are known for imparting some of the desirable properties of natural or spun yarn to continuous filament yarn by modifying the texture thereof. 'As a result, numerous end uses formally dominated by spun or natural yarns are now amenable to continuous filament yarn. Continuous filament yarn whichhas been modified in some manner to increase its bulk, stretch, or both or" these properties, has become known as textured yarn. The types of textured yarn are classifiable and characterized by the form taken by the individual filaments after such filaments have been subjected to a texturizing operation. Such forms, resulting from a change in the surface geometry and texture of the otherwise smooth, continuous filaments include rather permanent crimp, loop, coil, and curl shapes. Vastly different methods and apparatus are used to impart one or more of these forms or specific characteristics to continuous yarn.

The present invention has to do particularly with an improved method and apparatus for texturizing continuous filament'yarns whereby the change in surface dimensions or texture is obtained by forming crimps in such yarn. A texturized yarn characterized as a crimped or bulked type yarn and presently having commercial acceptance is produced by forcing continuous filament thermoplastic yarn into what is commonly referred to as a crimper or stuffer box and by effecting a controlled removal therefrom. By compressing the yarn into the stutterbox, the individual filaments are caused to fold or bend sharply upon itself at intervals varying over a controllable range. While in such a crimped condition, the yarn is heat-set yarn while still in a severely crimped configuration. The yarn is then removed from the box in the form of a wavy, irregular, zig-zag crimp that imparts to the yarn a desirable increase in bulkiness, softness of hand, improved elasticity, etc.

Another commercial texturizing operation wherein bulk is accomplished by crimping the yarn also utilizes the stutter or crimper box technique to induce substantially permanent crimps in the yarn. This operation involves crimping a large number of ends in warp form followed by heat-setting in an autoclave or the like, necessitating a batch-type operation. Fabrics produced from this latter method likewise have a smooth and bulky surface texture.

The yarns treatedaccording to the two just described methods are characterized by sharp changes of curvature at more or less regularly spaced intervals. Obviously, there are fiber materialswhich do not lend themselves readily to crimping by such 'a method employing stutter boxes, since some fibers may be too brittle to withstand the strains and crimping pressure when successive lengths thereof are bent or folded upon one another as the fiber is crammed into the stuffer box. Hence, such procedures unfortunately may cause breakageto some extent and adversely aifect the strength and quality of certain yarns.

A further method of crimping heat-settable continuous filament yarn not employing theme of a stutter box involves knitting the yarn into a fibric, heat-setting the fabric, and thence unraveling the yarn. Obviously such an operation is expensive and, hence, it has not been widely accepted commercially save in novelty fabrics, although notable improvement of the yarn texture results.

Present day crimping apparatus conventionally employs a'crimper or stutter box whose operation is characterized by an automatically repeating, batch type cycle; That is, the filamentary material to be crimped is first fed into the stutter box in distinct batches without simultaneous Withdrawal of material therefrom, resulting in a non-uniformity of treatment due, in'part, to the fact'that that portion of each batch which was last forced into the stuffer chamber has been subjected to the-influences thereof for a shorter period than the earlier said portions. As such a stutter box reaches its predesigned capacity, it is rhythmically tripped to expel its contents down stream, which mode of operation renders it most difficult to render any refinements in treatment of the material while'it is in the stutter box when such'treatments are time sensitive. These shortcomings have resulted in a continuouseiiort to contrive some means whereby the action of the stutter boxis rendered more nearlycontinuous whereby the material beingtreated is caused to remain within the stutter box or under its' influence for a preciselyco'ntrollable length of time which may readily be maintained uniform along successive lengths of the material being treated, resulting in a higher quality product. 7

A further problem is encountered in the use of stuffer box type crimping apparatus where it: is desired to set thermoplastic filaments while retained in their highly convoluted condition within the stutter box, This may be accomplished by providing some means of positively cooling the yarn a sufiicient length of time for the internal stresses produced by the crimping'act-ion to ibe relieved so that the tendency of the crimp to open up after the material is removed from the chamber is eliminated. In

1 the case'of thermoplastic filaments, such as acetate rayon,

by the application of well known heating agent which,

- in some instances, is followed by positive cooling of the nylon, Dynel, Orlon, Acrilan, the cooling means is so designed that the material cools to a temperature below that at which there is any tendency for plastic flow'while still packed 'in the chamber. Since the stresses have been relieved by maintaining the material in heated condition in the crimping chamber, the crimp becomes permanently set upon cooling. Of course, suitable moisture conditions may be established within the crimping chamber to Optimize the crimping and setting treatments depending upon the type of material being processed. Provisions for carrying out such after-treatments has entailed the use of additional, sometimes complicated and expensive, equipment. There has, therefore, been a continuing search for some means of accomplishing this after-treatment function that would not involve extensive redesign or replacement of existing equipment.

With these problems and shortcomings in mind, it is therefore one object of my invention to provide a stuffer box type crimping apparatus having novel and improved means for continuously maintaining the material being treated for a constant, controllable period of time within a the crimping chamberto thereby promote uniformity of drawal of the c-rirnped material from the stutter box so as to maintain continuouslyconstant the quantity of material in the crimping chamber. Still another object of this invention is to provide in a stutter box type crimping apparatus an improved means for continuously metering the quantity of material contained within the crimping chamber whereby such quantity is maintained constant, such means comprehending the use of a pneumatically-actuated sensing means. Yet another object is to provide for thesetting of crimped, thermoplastic filamentary material while maintained in its compacted condition within the crimping chamber. Another object is to provide such asetting means which employs the use of a cooling gas exhausted through the interior of the crimping chamber. A still further object of my invention is to provide, in a stuffer box type crimping apparatus, an improved means for continuously maintaining constant the quantity of material within the crimping chamber, which means is of such design as to also accomplish setting of a thermoplastic yarn while maintained in its crimped condition within the chamber. A still further object is to provide an improved method of crimping filamentary material employing the use of stutter box type crimping apparatus, which method results in main taining continuously a constant quantity of material within the crimping chamber. A further object is a method of crimping and setting filamentary material continuously with high uniformity of treatment. Still another object is to provide a method of pneumatically metering the quantity of material within the crimper chamber in a manner to maintain constant the length of time such material is under treatment, while, at the same time, providing for the setting of such materials while in its confined condition.

According to one aspect of the present invention the foregoing and other objects are attained by providing within a stufier box type crimping apparatus an improved means for maintaining constant'the time'and quantity of material contained within the crimping chamber in order to promote greater uniformity of treatment, which meanscomprehends the use of supplying a source of gas under constant pressure into the interior of the crimping chamber, sensing gas pressure fluctuations induced by fluctuations in the degree of compaction of the material within such container, and actuating a withdrawal mechanism in such fashion as to maintain continuously constant the quantity of material confined therein. Such a means may take the form of a conduit communicating with the lower regions of the crimping chamber and a constant source of pressure. The pressure fluctuations Within such a conduit are monitored by any suitable means, such as a spring-biased, pneumatically-actuated piston, which may, in turn regulate a variable speed takeup mechanism.

According to another aspect of this invention, the foregoing and still other objects are accomplished by providing a method of promoting uniformity of treatment within a stuffer box type crimping apparatus, which method employs the steps of pneumatically monitoring the quantity of material confined within the stuffer chamber and regulating a conventional takeup mechanism in such fashion as will maintain the level of material constant therein. A concomitant advantage in pneumatically monitoring the degree of compact-ion, and therefore the quantity, of material within the stuifer box is that of effecting a cooling of the material while it is still confined in its highly convoluted condition within the chamber, thereby effecting a much greater permanence of crimp.

The nature of the invention will be better understood by referring to the following detailed description, taken in connection with the accompanying drawing forming a part thereof, in which a specific embodiment has been set forth for purposes of illustration and not limitation.

Referring now in greater detail to the drawing, there is shown a simplified, partially schematic, partially sectionalized representation of a specific embodiment of my invention in the form of a crimping system employing the use of a crimping chamber or stufler box. Such a system, generally designated by reference numeral 10, would include a source of filamentary tow, represented in the drawing as supply package 12, for supplying tow through suitable supply guides and pulleys 14. The filamentary tow or yarn is introduced into the crimping apparatus by way of feeder rolls guide 16 into the nip of feeder rolls 1%, 2t which in turn force feed the yarn into crimping chamber or stuffer box 22 by way of the saddle block 24. The details of the mounting and drive mechanism for the feeder rolls 18, 20, which do not comprise a part of my invention, or such as to maintain the rolls in face-to-face, rolling contact and to drive same in opposite directions as indicated by the arrows. For reasons later to be discussed, the feed rolls are preferably driven at a constant peripheral speed slightly greater than the average rate of withdrawal of the material from the downstream end of the crimping chamber 22. The saddle block 24, provided with curved surfaces 26 and upstanding ear portions 28 conforming to curvature feeder rolls 18, 2t serves to therefore correct the filaentary material from the feeder rolls in a smooth, nonjamming fashion and to transmit same into the crimping chamber 22 where the material is lapped upon itself into the highly crimped conformation indicated pack 30. Obviously the saddle block may be in the form of a smooth, integral extension of the crimping chamber 22 if manufacturing considerations so suggest.

The crimping chamber 22 may be provided with a suitable heating agent, especially where thermoplastic material is being treated, which heating agent may conveniently take the form of a jacket mounted externally of the chamber and housing the high temperature end of a conventional heat exchanger or a suitable electrical resistance heater. Such a heating jacket may extend over the entire length of the crimping chamber or be limited to a portion thereof, such as the upper portion designated by bracket H in the drawings. A cooling zone, later to be discussed, may occupy the zone designated by the bracket labeled C in the drawing.

The filamentary material to be treated enters the crimping chamber by way of feeder port 32 and is withdrawn therefrom by way of withdrawal port 34. Upon being withdrawn from the crimping chamber, the filamentary material is taken over suitable guides pulleys to a takeup spindle 36 provided with a suitable traversing mechanism 38, these being shown in highly simplified form, any conventional take-up spindle and associated traveling mechanism being suitable for the purposes at hand.

As discussed hereinbefore, a primary object of my invention is to provide a practical means for insuring that successive lengths of the filamentary material are subjected to the influences of the crimper chamber for uniform periods of time, which means will, as an inherent function of its design, effect a cooling and, hence, setting of the material being treated prior to its being released from its highly crimped and compacted condition within the chamber, thereby insuring a more permanent crimp. One possible embodiment of such a means, as depicted in the drawing,'comprehends the use of a pneumaticallyac'tuated monitoring and speed control mechanism. This system or mechanism is seen to comprise a source of gas under constant" pressure, symbolically indicated in the drawing as a constantpressure gas reservoir 40, which is placed in communication with the lower region of crimping. chamber 22 by means of a supply conduit 42. A

monitoring conduit 44 communicates between supply con' cated in the drawing, normally consist of a variable in ductance coil, the setting of. which is controlled in this case by lever 56, connected to disc-like elements to maintain such elements'in clamping engagement with varying degreeslof compression. By this means, a tow or filament trained between such disc-like elements may be subjected torvarying degrees of tension down stream thereof to maintain the take-up package at uniform tension.

A variable speed drive mechanism, symbolically indicatedat 60, which is connected to drive the take-up spindle 36 by means of drive shaft 62, is regulated according to the movements of lever 56 by way of pivoted crank arm 64, which is mounted to pivot about fixed pin 66.

It "may be found desirable to increase the sensitivity of my monitoring system by providing a pair of spacer orifices, a primary orifice 68 and a secondary orifice 70 located adjacent the juncture of the supply conduit 42 with the wall of the crimping chamber 22. In such an instance, the secondary orifice may'conveniently be formed in the wall of the crimping chamber proper and the primary orifice 68 spaced up-stream of the supply conduit 42 a distance sufficient to accommodate the interconnection of the monitoring conduit 44 with the supply conduit.

In operation and with gas under constant pressure exhausted into the crimping chamber, as such chamber becomes filled with the material to be treated and such material is subjected to increased compaction, the air flow will be essentially cut off due to the plugging of the secondary orifice 70 in the wall of the crimping chamber. This will in turn cause a build-up of pressure in the monitoring conduit 44, which build-up is communicated to the piston 46, biasing the piston to the left, as viewed in the drawing to actuate lever 56 in a clockwise direction and crank arm 64 in a counter-clockwise direction about pivot pin 66. The magnetic tension device 54 is so mounted that a clockwise adjustment by lever 56 will effect a decrease in tension applied to the filamentary material passing therethrough. On the other hand, the variable speed drive mechanism 60 is mounted with respect to crank arm 64 so that a counter-clockwise motion of the latter will effect an increase in output speed, thereby increasing the take-up spindle speed. It is therefore seen that an increase in compaction of the material confined within the crimping chamber 22 above a predetermined level will effect an increase in the rate of withdrawal of the material from the crimping chamber by virtue of an increase in the speed of a take-up spindle 36, which is accompanied by a decrease in the tension applied to the material by the magnetic tension device 54, thereby insuring a wind-up at constant tension regardless of the speed of the takeup operation. In similar fashion, should the degree of material compaction within the crimping chamber decrease below a predetermined level, the pressure sensed by the monitoring conduit 44 will decrease, thereby allowing the piston 46 to move to the right, which, in turn, manipulates magnetic tension device to a position of increased tension and the variable speed drive mechanism to a position effecting a lower out-put speed. It will be appreciated that, by making proper adjustments for a given installation, my device may beemployed to regulate the degree of compaction within the crimper chamber, thereby regulating the quantity of material therein within a quite narrow range, with the result that successive lengths of the material subjected to treatment will experience a uniform length of time within the crimping chamber.

The orifices 68, 70 serve to amplify pressure fluctuations within the supply conduit due to their throttling action, thereby providing increased sensitivity of the withdrawal mechanism, whereby fluctuations in the degree of material compaction may be controlled, over a narrower range.

It will be further appreciated that, by use of my crimper regulating mechanism, the 'airstream which is employed as a monitoring medium willhave the concomitant ad vantage of effecting a'cooling of the material under treatment as it passes through the lower regions of the crimping chamber which, especially in the case of thermoplastic yarns or tow, greatly increases the permanence of the crimping treatment. Additional exhaust ports for dissipation of the pressurized air may be provided in the walls of the crimping chamber. In most instances, however, adequate venting is provided by the feeder and withdrawal ports 32, 34, respectively.-

It is to be emphasized that the take-up mechanism to be employed in the practice of my invention is not limited to that described and illustrated but may take any of many varying forms well, known in the-art.- Forexample, ,whereit is not essential to provide a take-up package of constant tension fthroughout, the tension regulating device 54 may be entirely eliminated, wherein any increase in the speed of withdrawal of the material from the chamber will be compensated by the expansionability of the crimps therein. In such an event, it maybe found expedient to interconnect the piston 46 directly with the variable speed drive mechanism. 60. May other such variations may readily be accomplished without departing from the spirit of my invention in that my contribution resides in the coaction between the pneumatically-actuated monitoring or regulating system and any take-up mechanism it may be found desirable to employ.

It is further to be emphasized that the particular motion generating and transmitting means is not limited to the particular spring-biased piston arrangement described and illustrated in that hydraulic or electrical means, such as a variable saturable core reactor could as well be employed.

Obviously numerous modifications and variations of the present invention are possible in the light of the above teachings. It is therefore to be understood that within the scope of the appended claims the invention may be practiced otherwise than as specifically described herein.

What is claimed is:

1. In a crimping apparatus of the type having a stufier box, means for feeding filamentary material into said stutter box and variable speed withdrawing means operative to remove material from said stuflfer box, an improved regulating apparatus for regulating the rate of withdrawal so as to maintain constant the quantity of material within said stuifer box, said regulating apparatus comprising a source of gas under constant pressure, conduit means fluidly interconnecting said gas source with the interior of said stuffer box, spring-biased piston means in fluid communication with said conduit means, and a mechanical linkage interconnecting said piston with said variable speed withdrawing means whereby, upon an incipient change in the degree of compaction of material within said stuffer box, the gas pressure within said conduit changes to move said piston, thereby actuating said linkmeans, said pressure sensitivemeans comprisinga spring- 'biased piston in fluid communication with said conduit,

a variable speed drive drivingly engaging said Withdrawing means, mechanical linkage means interconnecting said piston with said variable speed drive whereby, upon an increase in material compaction within said stutter box, the'gas pressure Within said conduit increases to cause said piston to move against said spring to thereby increase the rate of said variable speed drive to thereby increase the rate of material Withdrawal from said stutter box suiticiently to maintain substantially constant the quality of material contained tlierewithin.

3. A crimping apparatus regulating means for use in obtaining improved uniformity of treatment 'by a crimping apparatus having variable speed means for Withdrawing material from said apparatus, said regulating means. comprisingpneumatically-actuated sensing means fluidly communicable with the interior of said stutter box and operative to continuously indicate the degree of compaction of the material containedtherewithin, motion generating and transmitting means interconnecting'said sensing means with said variable speed drive means, said pneumatically-actuated sensing means comprising a source of gas under constant pressure, a conduit communicating between said gas source and the interior of said stutter box, throttling means mounted interiorly of said conduit biased piston in fluid comniunication with the interior of said conduit at a point" intermediate said throttling means and said stutter box, and mechanical linkage means interconnecting said piston and said variable speed withdrawal means, whereby upon a change in the degree of material compaction within said stuffer box, the rate of said variable speed drive means is regulated to maintain constant the quantity of material contained within said stutter box.

4. An improved method of crimping filamentary material employing crimping apparatus of the type characterized by a stutter box having means to feed and withdraw said material from said box, said method comprising the steps of pneumatically sensing the degree of material compaction Within said stutter box, varying the rate of Withdrawal indirect proportion to any change in the degree of compaction to thereby maintain constant the quantity of material within said stufier box, the pneumatically sensing step being further characterized by exhausting gas under constant pressure into the exit region of said stutter box, whereby the material is set in its crimped condition prior to withdrawal from said box to thereby provide a more permanent crimp.

References Cited in the file of this patent UNITED STATES PATENTS 2,407,100 Richardson Sept. 3, 1946 2,575,839 Rainard Nov. 20, 1951 2,686,339 Holt Aug. 17, 1954 2,758,358 Shattuck Aug. 14, 1956 2,820,988 Wegener Jan. 28, 1958 2,843,882 Lewis et al July 22, 1958 2,922,197 Brown Jan. 26, 1963 2,960,730 Shattuck Nov. 22, 1960 3,022,545 Wylde et al Feb. 27, 1962 3,111,740 Stanley Nov. 26, 1963

Claims (1)

1. IN A CRIMPING APPARATUS OF THE TYPE HAVING A STUFFER BOX, MEANS FOR FEEDING FILAMENTARY MATERIAL INTO SAID STUFFER BOX AND VARIABLE SPEED WITHDRAWING MEANS OPERATIVE TO REMOVE MATERIAL FROM SAID STUFFER BOX, AN IMPROVED REGULATING APPARATUS FOR REGULATING THE RATE OF WITHDRAWAL SO AS TO MAINTAIN CONSTANT THE QUANTITY OF MATERIAL WITHIN SAID STUFFER BOX, SAID REGULATING APPARATUS COMPRISING A SOURCE OF GAS UNDER CONSTANT PRESSURE, CONDUIT MEANS FLUIDLY INTERCONNECTING SAID GAS SOURCE WITH THE INTERIOR OF SAID STUFFER BOX, SPRING-BIASED PISTON MEANS IN FLUID COMMUNICATION WITH SAID CONDUIT MEANS, AND A MECHANICAL LINKAGE INTERCONNECTING SAID PISTON WITH SAID VARIABLE SPEED WITHDRAWING MEANS WHEREBY, UPON AN INCIPIENT CHANGE IN THE DEGREE OF COMPACTING OF MATERIAL WITHIN SAID STUFFER BOX, THE GAS PRESSURE WITHIN SAID CONDUIT CHANGES TO MOVE SAID PISTON, THEREBY ACTUATING SAID LINKAGE-CONTROLLED VARIABLE SPEED WITHDRAWING MEANS TO VARY THE RATE OF WITHDRAWAL.

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