US2076273A - Elastic thread - Google Patents

Description

April6,1937. T. HARRIS 2,076,273

ELASTIC THREAD Filed Sept. 30, 1935 INVEN TOR.

A TTORNEYS.

Patented Apr. 6, 1937 UNITED STATES PATENT OFFICE ELASTIC THREAD Application September 30, 1935, Serial No. 42,743

16 Claims.

This invention relates to a covered elastic thread, and has for one of its objects the provision of an elastic thread which will have a complete covering thereabout, which covering will permit more freedom of action in expansion and contraction of the thread than the usual spun and twisted fibrous covering helically wrapped about' the core.

Another object of my invention is to limit the m elongation of the yarn by means of the covering.

Another object of the invention is the provision of an elastic thread which will not kink but rather lie flat when little or no tension is applied thereto.

' Another object of the invention is to provide a 15 thread which will be soft to the touch and extremely flexible and pliant.

Another object of the invention is to provide a core which will assist in retaining a non-twisted covering in position thereon.

Another object of the invention is the provision of a thread in which each of the plurality of coverings will be of untwisted fibers with adjacent layers of the covering wrapped in opposite directions about the central elastic core.

With these and other objects in view, the invention consists of certain novel features of construction, as will be more fully described, and particularly pointed out in the appended claims.

In the accompanying drawing:

Fig. l is an enlarged elevation showing the core and covering layers as positioned on the core and wound in opposite directions;

Fig. 2 shows a yarn with a portion of one wrapping thereabout;

Fig. 3 is an enlarged view illustrating the yarn having a single covering layer as contracted and somewhat kinked by reason of the twist in the core; and

Fig. 4 is a diagrammatic View illustrating the 40 application of the second covering upon the elastic" core covered with one layer.

Fig. 5 is a perspective view of a twisted rubber core with a square cross section.

Commercial elastic yarn at the present time 5 usually consists of a rubber core about which there is helically wrapped a non-elastic twisted fibrous thread of material. This thread is wrapped about the core when the core is stretched and prevents contraction of the thread to its 50 original naked rubber size, thus leaving the core constantly under tension. On the other hand, if this thread was not stretched to its limit when covered, this covering would restrict the thread to a certain amount and prevent it from stretching 55 to the extent it wouldwithout the covering; thus.

the commercial yarn is limited in its contraction and extension, and in order to provide a greater range of extension and contraction for a covered elastic thread I have used a covering of fibers which will be relatively untwisted and I wrap these on the elastic core by their delivery at substantially right angles to the travel of the core and at a speed which will cause the non-elastic fibers to be wrapped upon the core with a very short pitch or at an angle approximating a right angle to the direction of travel of the core; and in order that a second covering may be assembled on the yarn I cause a twisting of the previously covered yarn in the opposite direction but with a smaller number of turns per inch than that first used so that the twist placed in the core and its covering will be partially taken out at the time of the second covering of the yarn.

With reference to the drawing, the core may be a vulcanized rubber elastic thread although any suitable elastic core may be used which is covered by non-elastic fibrous material II which is relatively untwisted and is usually positioned or placed upon the elastic core I!) when the same is in stretched condition by reason of the elastic core being operated upon by an apparatus such as shown diagrammatically in Figure 4. The rubber core is nipped by a pair of rolls I2 and also by a pair of rolls M'which are traveling at a rate faster than the rolls l2 so as to stretch the rubber strand between the nips of the rolls I2 and i4 about 400%. This stretch is maintained between the nip of the rolls l4 and the ring and traveler of thepackaging means, by using a traveler of sufiicient weight while at the same time a twist I is placed in the rubber strand and at a point between the packaging means and the nip of the rolls l4 untwisted fibers approach at right angles to the travel of the core from a drafting mechanism to be delivered at a point Hi to be wrapped about the rubber core, thus placing a covering H upon the core, which covering by reason of its wrapping limits the extension of the core.

It is found, however, that if tension is relaxed on the strand with the single covering thereon such as II that it will contract and kink up or tend to twist about itself giving somewhat the appearanceof the strand shown in Figure 3; in fact the contraction is such that the rubber is under no tendency to further shorten the length which I may term a static condition, and in order that the tendencyto kink may be reduced or eliminated I pass the strand consisting of the core l and its covering ll again through a similar apparatus where the covered nipped by rolls l2 similar to that previously provided. However, in the second passage through a similar apparatus the spindle of the packaging means will be caused to travel in the opposite direction but at a speed to place in the strand substantially half the twists or a sufiicient number of twists to take out the kinks which would otherwise occur as above mentioned and shown in Figure 3; and in this passage I assemble a second covering l1 upon the core and covering I I in the opposite direction as shown more clearly in Figure 1, the second covering being delivered and assembled in a similar manner between the nip of the rolls l4 and the traveler of the packaging means where the stretch is maintained and the twist occurs, as before mentioned. i

In this manner I obtain two coverings l l and I1 upon a rubber core It, the rubber core being twisted in one direction to assemble the first covering thereon which thus is wrapped in the same direction as the twist in the core, while the next covering is wrapped in the opposite direction about the core and its cover at the same time removing some of the twists placed in the core in its first layer of covering, although leaving a suificient number of twists in this first applied core and covering to maintain the same in assembled relation thereon, the delivery in speed at the time of nipping being such that a very short angle is provided which I find enables the coreto have a, large amount of elasticity before being bound by the covering thereon, and in this manner the extension of the thread is greater and also the contraction of the thread is greater, thus providing more freedom of action and a longer range of extendibility and contractibility than that provided in the covered thread having twisted yarns for forming the covering thereon, while by reason of my double covering with these untwisted fibers I may take the kink out of the yarn enabling it to be better handled without tension.

The twisting of the core also assists in holding the non-twisted fibrous covering on the core strand I0 is again especially upon contraction as the surface provided by the twist tends to grip the innermost fibers of the covering and hold them fast upon the core. This is particularly true where a core of rectangular cross section such as shown at IS in Fig. 5, is used. The twisted corners I! of the square core are in somewhat of a corkscrew efi'ect and upon contraction bind the fibers of the covering between them. The rectangular structure when twisted, becomes substantially round for covering purposes. i

The foregoing description is directed solely towards the construction illustrated, but I desire it to be understood that I reserve the privilege of resorting to all the mechanical changes to which the device is susceptible, the invention being defined and limited only by the terms of the appended claims.

I claim:

- 1. An elastic single yarn comprising a twisted core of elastic material covered by a strand wound thereabout in a helical path and in the same direction as the twist of the core, said strand com prising relatively non-twisted fibers arranged sufficiently coherently by reason of them being twisted about the core as to give them sufiicient strength to limit the extension of the core material.

g. An elastic single yarn comprising a core of and I4 and cause a stretch.

elastic material having relatively non-twisted fibers arranged in a generally helical path about the core material and ,with a sufficiently long pitch so that upon contraction the core material of the yarn may return to substantially static condition under substantially no tension and the covering substantially completely covers the core material in any degree of stretch.

3. An elastic yarncomprising a core of elastic material twisted sufiiciently to provide helical ridges along its surface and having relatively non-twisted fibers arranged in a generally helical path about the core material and in a direction to cause the twisted core material to assist in more securely holding the fibers assembled about the core material.

4. An elastic yarn comprising a core of elastic material twisted sufiiciently to provide helical ridges along its surface and having relatively non-twisted fibers arranged in a generally helical path about the core material and in the same direction as the twist of the core whereby the twisted core material assists in more securely holding the fibers assembled about the core material.

5. An elastic yarn comprising a core of substantially rectangular cross section in condition twisted sufiiciently to provide helical ridges along its surface and relatively non-twisted fibers arranged in a generally helical path about the core whereby the twisted core assists in more securely holding the fibers assembled about the core.

6. An elastic single yarn comprising a twisted core of elastic material having relatively nontwisted fibers arranged generally in a helical path about the core material in one direction and another layer of fibers helically disposed in the opposite direction about the first layer of fibers, the twist in the core and the disposition of the fibers in the outer covering being substantially equal and opposite.

7. An elastic single yarn comprising a twisted core of elastic material having relatively nontwisted fibers arranged generally in a helical path about the core material in one direction and another layer of relatively non-twisted fibers helically disposed in the opposite direction about the first layer of fibers, the twist in the core and the disposition of the fibers in the outer covering being substantially equal and opposite.

8. An elastic yarn comprising a twisted core of elastic material having relatively non-twisted fibers arranged in a generally helical path about the core material in the same direction as the twist of the core and another layer of fibers helically disposed in the opposite direction about the first layer of fibers, with the pitch of said helical path sufiiciently long to permit contraction and prevent the core from being held under tension when released.

9. An elastic yarn comprising a twisted core of elastic material having relatively non-twisted fibers arranged in agenerally helical path about the core material and in the same direction as the twist of the core and another layer of fibers helically disposed in the opposite direction about the first layer of fibers.

10. An elastic yarn comprising a twisted core of elastic material having relatively non-twisted fibers arranged in a generally helical path about the core material in one direction and in the same direction as the twist of the core and another layer of non-twisted fibers helically disposed in the opposite direction about the first layer of fibers, the twist in thecore and the disposition of the fibers in the outer covering being substantially equal and opposite.

11. The method of forming elastic yarn which 6 consists in twisting and advancing an elastic strand under tension and wrapping thereabout relatively non-twisted fibers in a helical path by reason of said twisting with the pitch of said helical path sufiiciently long to permit contraction and prevent the core from being held under tension when released.

12. The method of forming a covered elastic thread which consists in feeding an elastic core in stretched condition, twisting it about its path of travel and delivering relatively nontwisted fibers at substantially right angles to the path of travel of said core to wrap the core in a helical path said wrapping of the fibers twisting them sufficiently to give them strength to 2 limit the extension of the core.

13. The method of forming a covered elastic thread; which consists in feeding an elastic core in stretched condition, twisting it about its path of travel by revolving only one of its ends and delivering relatively non-twisted fibers at substantially right angles to the path of travel of said core to wrap the core in a helical path, said wrapping of the fibers twisting them sufficiently to give them strength to limit the ex- 30 tension of the core.

14. The method of forming a covered elastic yarn, which consists in feeding and stretching an elastic core, then maintaining said core in stretched condition and twisting it subse- 35 quently to said stretching, and drafting relative- 1y non-twisted fibers and delivering them to said core without twisting the fibers to wrap the core in a helical path, said wrapping of the fibers twisting them sufiiciently to give them strength to limit the extension of the core and the pitch of said wrapping being sufiiciently long so as to permit contraction to such an extent that the elastic core is under substantially no tension.

15. The method of forming a covered elastic yarn, which consists in feeding and stretching an elastic core, then maintaining said core in stretched condition and twisting it subsequently to said stretching by revolving only its delivery end, and drafting relatively non-twisted fibers and delivering them to said core without twist to wrap the core in a helical path, said wrapping 'of the fibers twisting them sufiiciently to give them strength to limit the extension of the core and the pitch of said wrapping being sufliciently long so as to permit contraction to such an extent that the elastic core is under substantially no tension.

16. The method of forming a covered elastic, yarn, which consists in twisting and advancing an elastic core and delivering relatively non-twisted fibers to said core to wrap about the core in a helical path and subsequently twisting the covered core in the opposite direction by a lesser number of revolutions and advancing the same while simultaneously delivering nontwisted fibers to said covered core" to wrap about the same and form a second layer of covering on the core.

THOMAS HARRIS.

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