US2012984A

US2012984A - Apparatus for tension spinning

Info

Publication number: US2012984A
Application number: US402591A
Authority: US
Inventors: Bradshaw William Henry
Original assignee: DuPont Rayon Co
Current assignee: DuPont Rayon Co
Priority date: 1929-10-26
Filing date: 1929-10-26
Publication date: 1935-09-03
Anticipated expiration: 1952-09-03

Description

Sept. 3,; E

w. H. BRADSHAW APPARATUS FOR TENSION SPINNING Filed Oct. 26, 1929 2 Sheets-Sheet 1 TORNEY 3, 1?? w. H. BRADSHAW APPARATUS FOR TENSION SPINNING Filed Oct. 26, 1929 2 Sheets-Sheet 2 IN N R ATTORNEY Patented Sept. 3, 1935 stares tartarv earns erris 3 claims. (or. 18--8) This invention relates to the art of producing artificial threads. More particularly, it relates to an apparatus for producing artificial threads from viscose by the so-called tension spinning proc- Inthe manufacture of artificial threads from viscose, threads of high tensile strength can be obtained by the so-called tension spinning process, whereinthe threads are placed under tension and stretched at some stage of their manufactures; One common method of effecting the tension was to arrange guides in the bath or above it, whereby the thread passing therearound-produced friction which resulted in an increase in tension on the thread between the guide and-the collecting .device. This tensionresulted in the thread stretching between the guide and the collecting device, whereby products having improved strength were obtained. These bath guides were made of glass, porcelain or any other suitable material, and they were either stationary or rotating. Those which were stationary depended on sliding friction between the thread and the guide to produce the tension. Such an arrangement of parts had several disadvantages. One of the most serious was the production of thread having a lack of uniformity of physical characteristics. This was dueto the variable slidingfriction between the thread and theguide, whereby a marked lack of uniformity of tension wasobtained. Those bath guides which rotated practically eliminated the sliding friction of the thread on the guide. There was, however, still present the friction between the guide and its shaft. Accordingly, there was-also some evidence of nonuniformity in the physical characteristics of the thread, although it was relatively small;

I have found that a successful way'to secure substantially uniform stretch in the thread" is to stretchit between two positively driven wheels, the second one having a peripheral speed greater than the first. The difference in peripheral speeds may be obtained by employing wheels of difierent sizes, or a second wheel having a diameter equal to the firstwheel may be operated at a greater speed. In the case of a bobbin'machine; the bobbin may be used as a second wheel and a pbsitively driven wheel may be arranged ahead or in front of the bobbin. In the bucket process the usual godet or feed wheel may be used as a second wheel and an auxiliary wheel maybe arranged ahead or in front thereof. By adjustment of the relative peripheral speeds of the two wheels,"the thread may be stretched to any desired degree. Artificial thread so produced will have ahig'h and cautions to make it successful.

- rotating mechanism which reducesto a minimum remarkably uniform tensile strength in both the wet and dry state. Furthermore, the elongation and the dyeing characteristics of the yarn will be.

remarkably uniform. This method of securing substantially uniformstretch requires certain pre 5 It has been found that, when a considerable stretch is applied be-' tween the two wheels, there is a tendency forthe thread to slip on the wheels. This slippage hereafter called feed-wheel-slippage, results in nonuniform stretch which, as was the case with fixed guides, results in the production ofthreads having non-uniform tenacity, denier and dyeing properties.

I have found that this slippage can be substantially decreased or even substantially eliminated by increasing the are of contact of the thread on the feed wheel. In cases where the are of contact is increased to such an extent that the thread forms a complete wrap about the wheel, provision must be made to prevent the thread from riding on itself by providing lateral displacement of the thread on the wheel.

It is therefore an object of this invention to provide an apparatus for tension spinning-which will produce a thread having a relatively high and substantially uniform tensile strength and at the same time substantially uniform elongation, dye index and other physical properties. a

L'Another object of this invention is to provid $3 an apparatus for the production of artificial threads by the stretch spinning process, whereby the threads will be given asubstantially uniform stretch.

Another object of this invention is to provide 7 an apparatus for the production of artificial threads by the stretch spinning process, wherein slippage on the feed wheels is substantially eliminated. v

A further object is to provide a mechanism for producing artificial threads by the stretch spinning process which comprises, among other elements, a plurality of wheels on which. a thread is wrapped one or more times rotating at increasingly greaterfperipheral speeds combined with a suitable, device for preventing riding of the thread on itself. p 7

Another object of this invention is to prevent this riding of the thread on itself by means of a the irregularities caused by sliding friction.

Other objects will appear from the following description; appended claims and accompany}- ing drawings in which;

Figure 1 illustrates a diagrammatic arrangeto reduce or eliminate sliding friction.

Figure 4 is a diagrammatic arrangement of a simple way of stretching the thread between two wheels with a provision for preventing the thread from chafing on itself.

Figure 5 is a diagrammatic arrangement of wheels whereby a progressive stretch may be obtained.

Figure 6 illustrates a set-up wherein a stretch may be obtained between two wheels, one of said wheels being disposed in the bath.

Figure '7 diagrammatically illustrates one embodiment of this invention in which the thread is stretched between two wheels on which feedwheel-slippage is overcome by causing the thread to make more than one wrap around each wheel, and in which a rotary guide is used with each wheel to produce a lateral displacement of the thread on the wheels and so prevent the thread riding on itself without introducing sliding friction as far as the thread is concerned.

Figure 8 is a detail-ed side elevation of one of the wheels shown in Figure '7 and specifically wheel I.

Figure 9 is a detailed side elevation of one of the wheels of Figure 7 and specifically wheel I under which a fixed guide is use-d in place of the rotary guide.

Figure 10 is a side elevation of one embodiment of this invention as applied to a single feed wheel.

In spinning by the bucket process, wherein one feed wheel is used, the stretch is produced as a result of tension applied to the thread by means of suitably disposed thread guides and the thread passes from these to and over a feed wheel and downward into the bucket. When the tension passes a certain value for a given setup, the thread slips on the feed wheel and gives rise to threads of non-uniform characteristics. This slippage can be reduced or eliminated by increasing the arc of contact of the thread on the feed wheel as in Figure 1, wherein the thread T coming to the feed wheel I and leaving said wheel is in the relation shown.

In many cases because of the position of the other parts of the spinning machine, it is rather inconvenient to have the thread pass to the feed wheel, as shown in Figure 1. In these cases the arc of contact between the wheel I and the thread T passing thereover may be increased by the aid of some auxiliary means. In Figure 2 the thread T is illustrated as passing on and around the feed wheel I, the direction of the thread T to the wheel I being in any desired direction. To increase the arc of contact between the thread and the wheel, there is provided a fixed guide 2 suitably mounted on the spinning machine and about which the thread passes after it leaves the wheel I. The guide 2 is so dispose-d and mounted relative to the wheel I, that it causes the thread T to engage a larger portion of the periphery of the wheel, whereby the arc of contact is increased. By proper positioning of the guide 2 beneath and/0r adjacent the wheel, the arc of contact of the thread therewith may be increased or decreased as desired. The guide 2 may be formed of any of the usual materials used, such a sglass, porcelain, hard rubber, phenolic condensation products, etc.

In the set-up just described and illustrated in Figure 2, tension due to the sliding friction of. the thread on the guide 2 will be set up between the guide 2 and the collection device (not shown). In some instances this tension is irregular and non-uniform, resulting in the production of a product having non-uniform physical characteristics. To avoid this, instead of using a fixed guide 2, a rotary guide 3 (Figure 3) suitably mounted on the spinning machine may be used. This rotary guide may be positioned relative to the feed wheel I in the same manner as the fixed guide 2. If desired, it may be positively driven, but preferably it is freely mounted so that the passage of the thread therearound rotates it, whereby substantially no sliding friction between the guide and thread is obtained.

To obtain very good results, it is necessary to spin at relatively high tensions. This, of course, increases the possibility of feed-wheel-slippage. To correct or avoid this, a considerable arc of contact between the thread and the feed wheel is necessary. I have found that wrapping the thread one or more times about the feed wheel produces very satisfactory results. Figure 10 illustrates one manner in which this can be accomplished. As hereinafter described in detail, the thread T coming from the coagulating bath (not shown) passes behind a post guide l, around the feed wheel and down to and around the lateral displacement guide 5 and then up and around the feed wheel again in a plane other than that in which it first passed around the feed wheel and finally down to the spinning bucket.

This invention in its broad aspect relates to a method and apparatus of tension spinning which will produce a thread having a high and uniform tensile strength and at the same time uniform elongation, dyeing and other physical properties. This invention contemplates a uniform stretch on the thread.

One embodiment of my invention comprises, among other steps, passing the thread over two positively driven wheels rotating at increasingly greater peripheral speeds so that a substantially uniform stretch is applied to the threads. In order to secure this uniform stretch when working with high tensions and stretch, the slippage of the thread on the feed wheels must be eliminated or decreased and means are provided for doing this.

In Figure 4 there is illustrated a diagrammatic arrangement including two wheels. The thread T coming from the coagulating bath passes upwardly, in back of the guide 6 and around the wheel I. After contacting with the wheel I, through a large arc, the thread passes in front of the guide 6 on to and around the second wheel I and thence down into the funnel and bucket not'shown. If desired, a guide 6' similar in construction and functioning in the same manner as the guide 6 may be provided to cooperate with the wheel I. In this set-up the large arc of contact is obtained, whereby slippage is prevented. for all but very high tensions. The guides 3 and 6 not only function to direct the thread to and from the wheels but also to prevent chafing thereof. The two wheels I and I are of such diameters or operate in such a manner that the wheel I. Such an arrangement will stretch the thread between the two wheels, any desired.

stretch being obtained by adjusting the relative peripheral "speeds of the wheels. It is apparent that various arrangements of wheels having a more or less complete wrap of thread therearound may be used. In Figure 5 there is illustrated a plurality of positively driven wheels I, 8, and 9 having different peripheral speeds, whereby a progressive stretch may be obtained. Insteadof employing wheels of the same size, the wheels maybe of different diameters but rotating at the same speed. If desired, this set-up may utilize

guides

6 and 6 for the same purposes as above described.

In Figure 6 another modification is illustrated. In this set-up one of the positively driven wheels III is submerged or partly submerged in the coagulating bath, the surface of which is shown at S. Referringto this figure, the reference numeral II designates a nozzle or spinneret diagrammatically illustrated, from which the solution forming the thread T is ejected into the coagulating bath. The coagulated thread then passes to the wheel II) directed, if desirable, by means of a bath guide I2 which may be either fixed or rotary. After a substantially complete wrap around the wheel I I), the thread passes around the fee-d wheel I and thence down into the bucket (not shown). If desired, there may be interposed between the wheels I and I a guide I3. Preferably, the guide I3 is so disposed that it prevents chafing of the thread.

In the above described modifications, referring to Figures 4, and 6, the thread is given a substantially complete wrap around the wheels. It is desirable in some cases to wrap the thread more than once around the Wheels. In such an operation it is necessary to provide means whereby the thread is laterally displaced on the wheels.

If a thread is continuously fed to a wheel and allowed to make more than a complete wrap around it, it will form a circle around the wheel in a plane perpendicular to the axis of the wheel; For this reason, when the wheel has completed one revolution, the oncoming thread will begin to ride on top of the thread already on the wheel and bind it tightly against the face of the wheel. If the thread is removed continuously after it has made more than a complete wrap, it will be injured or even broken by dragging it from under the following portion of the thread which has been laid on top of it. To overcome this difliculty I withdraw the thread from the wheel before it has made a complete wrap, lead it around a guide, preferably a grooved pulley, so placed that, when the thread is returned to the wheel,

it rides in another plane perpendicular to the axis of the wheel.

With this in view the rotating guide mechanism illustrated in Figures 8 and was designed.

The reference numeral I indicates the usual feed wheel, well known in the art, provided with a flange I4 on one end thereof and suitably mounted on a spinning machine in the wellknown manner (not shown). Disposed beneath the wheel I is a guide mechanism which prevents the thread from riding on itself by providing lateral displacement on the wheel. This guide comprises a wheel 5 formed with two flanges I5 and I6, one at each end thereoflforming a groove or channel IT in which the thread passes. Through the center of the guide there is a bore I8 by means of which the guide mechanism is on itself.

freely r'otatably mounted on'a glass axle l9 suitably-and adjustably disposed in a clamp secured on a block 2i, which is fastened to the frame 'of the machine and in such a position that the-wheel 5 is disposed in such relation to the wheel. I that the thread in its second wrap on the wheel I is displaced laterally with respect to the first wrap, so that the thread does not ride If desired, a washer 22 may be positioned between the clamp and the roller.

There may be provided, if desired, a post guide 4 which directs the thread on to the wheel. It isformed, as clearly illustrated in the drawings, on a bracket 723'adjustably secured in any suitable manner, as by screws 24, to the block 2|. The block 2! may be formed with a groove or recess in its upper face and serves as a drip collector.

My preferred modification, shown in Figure 7, also includes the use of the rotary guide mechanism illustrated in Figures 8 and 10. In the operation of this modification the thread T coming from the coagulating bath passes'behind a post guide 25 and is directed on to the wheel I. After making a less than one complete wrap around the wheel I, the thread leaves said wheel and passes beneath the rotating guide mechanism 5 prior to making another wrap on the 'wheel I. Finally, it passes off the wheel I on to the wheel I, as shown in Figure 8 at 26. After having traveled a part of a turn on the wheel I, it leaves the wheel and travels over and around the rotating guide mechanism 5 and then around the Wheel again and finally into the funnel guide 21 and bucket (not shown). It is clear that the guide mechanisms 5 and 5' prevent the thread from riding on itself by providing lateral displacement of the thread on the wheels I and I.

As an alternative to the rotary guide mechanism which I prefer, there can be used a fixed guide mechanism, one specific form of which is shown in Figure 9 as it could be applied to the wheel I in Figure 7.

A fixed pin 28 is formed integrally with a support or bracket 29 and is so located with respect to the wheel I that the thread, after passing around the guide 28, returns to the wheel I in a plane other than that in which it first passed around the wheel I. In this specific form a curved guide mechanism is used, although it is clear that other forms of fixed guides may be used, for example, a straight rod, or in the form of an inverted V suitably disposed could also be used. The bracket 29 is secured to a block 30 suitably mounted on the spinnning machine. If desired, the bracket 29 may be adjustably mounted on the block 30 or said block may be adjustably mounted on the spinnning machine.

It is to be understood that no definite arrangement of the wheels I and I is essential. Though in the preferred modification the wheels are disposed so that the thread travels in a horizontal direction therebetween, the invention is not restricted thereto. The wheels may be disposed in any position relative to each other, so that the direction of travel of the thread therebetween is horizontal, vertical or at any angle thereto. If desired, one of the wheels may be positioned within, near or adjacent the coagulating bath.

I claim:

1. An apparatus for stretching artificial thread comprising a plurality of spaced wheels around each of which a thread is to be wrapped one or more times, means to operate said wheels at different peripheral speeds, whereby the thread passing therebetween is stretched, a guide directing the thread on to at least one of said wheels and a separate guide mechanism for each of said wheels to laterally displace the thread ontsaid wheels, said guide mechanism comprising a freely rotatably mounted roller.

2. An apparatus for stretching artificial thread comprising a plurality of spaced wheels around each of which a thread is to be wrapped one or more times, means to operate said wheels at difierent peripheral speeds, whereby the thread passing therebetween is stretched, a guide directing the thread on to at least one of said wheels and a separate guide mechanism for each of said wheels to laterally displace the thread on said wheels, said guide mechanism comprising a freely rotatably mounted roller having a channel in the periphery thereof.

3. An apparatus for stretching artificial thread comprising a plurality of spaced wheels around each of which a thread is to be wrapped one or more times, means to operate said wheels at different peripheral speeds, whereby the thread passing therebetween is stretched, an adjustable guide directing the thread on to at least one of said wheels and a separate guide mechanism for each of said wheels to laterally displace the thread on said wheels, said guide mechanism comprising a freely rotatably mounted roller having a channel in the periphery thereof.

WILLIAM HENRY BRADSHAW.