US 2912722 A
Description (OCR text may contain errors)
Nov- 17, 1959 HOWELL I 2,912,722
FIBER PROCESSING UNIT Filed May 15, 1957 INVENTOR. EMORY L. HOWELL mww,
ATTORNEY United States Patent FIBERPROCESSING UNIT Emory L. Howell, Greenville,
S.C., assignor to The Dayton Rubber Company,
Dayton, Ohio, a corporation of Application May 15, 1957, Serial No. 659,304 v9 Claims. (Cl. 19-131 individual fibers are tightly compacted and twisted so as to impart considerable tensile strength to the strand. The drawing or drafting of the fibers is generally achieved by passing the same'through a series of pairs of nearly tangentially contacting rollers and/or aprons, the peripheral speeds of which increase successively throughout the series so that those pairs which are forward or in the direction of the travel of the roving will tend to pull and draw out the strand while the rollers and aprons rearwardly thereof will act as a brake thereon.
In most of the drafting systems currently in use such as the Whitin-Casablancas and the Saco Lowell-Roth systems, at least one, apron in the form of a flexible sleeve having an outer fiber contacting surface is employed. Such aprons are motivated by a powered roller in driving contact with the inner surface of the sleeve at the rear thereof. To provide a .planar apron surface for contacting the fiber, a supporting rod often referred to as a nose bar is employed to hold the apron at the front so that the normally cylindrical sleeve is held in elongated position during its travel about the driving roller and the nose bar. The nose bar itself is stationary and is so contoured and polished that the apron will slide readily thereover. In the Saco Lowell-Roth system, the tension of the apron is controlled by an idler or tension roller which usually rotates against the outer, fiber-contacting apron surface and urges it inwardly between the driving,
roller and the nose bar.
Because the outer, fiber-contacting surface of the apron must be of a carefully controlled resilience and modulus of elasticity so as to exert the proper pressure and grip upon the fiber being processed and because the inner surface of the apron must be carefully controlled as to resilience and friction properties so as to be properly driven for smooth operation about the various rollers and apron supporting bars, the material of which these apron surfaces are composed must be carefully selected. In the.
early stages of the development of fiber processing, it was'the common practice to form drafting aprons of leather processed in various ways as by impregnation with oil and the like to control its surface characteristics.
More recently however, it has been found that rubber.
and the various synthetic elastomeric materials such as synthetic rubber and particularly the copolymers of buta- 'diene and acrylonitrile provide improved drafting characteristics over a greatly extended operational life. Other synthetic plastic materials which have been advantageously employed in either the inner or outer apron surfaces have included other synthetic rubbers such as the butadiene-styrene copolymers, 'the polychloroprenes, polysulfides, and other synthetic, elastomeric plastic material such as the polyurethanes, polyamides,polyvinyl chlorides and the like as well as mixtures of these various materials.
in the case of all of the many synthetic materials and mixtures thereof which have been employed in fiber drafting aprons however, there has, for some unexplained reason, been a marked tendency for the accumulation of lint about certain of the drafting machinery parts. In both the Saco Lowell-Roth and Whitin-Casablancas systems for example, the use of a synthetic material on either of the apron surfaces has resulted in an accumulation of lint upon the nose'bar or apron supporting rod at each edge of the apron passing thereover. The individual fibers continue to build up at these points on the nose bar until theiraccumulation. is of sufiicient Weight that they will fall'ofii' "In many instances this mass of loosely assembled fibers falls directly into the strand being processed by the apron; and, since the fibers are so heterogeneously arranged, they cannot be properly drawn and aligned in the drafting process and will be only loosely associated even in the finished yarn.- Because these fibers are not drawn and spun they haveverylittle tensile strength and constitute a weakening defect known as a slub.
Similarly, in systems such as'the Saco Lowell-Roth system employing. atensioning or idler roller in contact With one of the synthetic apron surfaces, loose fibers tend to accumulate upon the surface of such roller at the points where it is' contacted by the apron. As such fibers build up about the tensioning Tor'idler roller, they tend to increase the effective diameter thereof with the result that the apron becomes .even further tensed orstretched; and in time the apron will therebybecome so taut that it cannot slide freely over the nose bar or other supporting components of the fiberdraftingmachinery with the result that the apronlwill Ibreak'or' bind to disrupt the drafting operation long before the aprons would otherwise have failed.-- I T It is accordinglyanobject of the present invention to It is a more specific object of the present invention to provide'an improved apronhaving surfaces of synthetic material for use in drafting. I
It is still a further object of the-present invention to provide a drafting apron for use in drawing machinery wherein the apron slides over a stationary supportingrod or nose bar such as in the Whitin-Casablancas and the Saco Lowell-Roth systems or is contacted by a'tensioning or idler roller as in the Saco Lowell-Roth system;
It is still another object of the present invention to provide a fiber drafting apron which will not result in an accumulation of heterogeneously arranged fibers upon the drafting machinery parts in contact with such apron.
It is still a further object of the'present. invention to provide a fiber drafting apron which will form a thread or yarn wherein all of the fibers are uniformly drawn and aligned. V v
Still another object of the present invention is to provide a method for the manufacture of suchfiber drafting aprons. i I
These and other objects and advantages of the present invention which will beap parent from a reading of the following disclosure are achieved by forming theinwardly disposed surface of the apron of any of the above enumerated synthetic materials to obtainthe advantages, of each and knurling such surface by providing a plurality of protuberances projecting inwardly therefrom. In' the preferred embodiments of this invention hereinafter described, these protuberances are preferably in the form of raised ribs or ridges of relatively small cross section and relatively closely spaced. While such ribs may be according to a variety of patterns, it has been found that definite improvements are achieved where the ribs are in parallel relationship extending transversely, longitudi nally or diagonally of the apron sleeve about its inner surface. An even more pronounced improvement over the prior art devices has been achieved Where the ribs rising from the inwardly disposed apron surface are of two classes, those ribs in each class being in parallel relationship diagonally of the sleeve and intersecting the similarly disposed ribs of the other class. It has been found that this criss-cross arrangement of the parallel ribs of the two classes intersecting to form a diamond-like pattern about the entire inner surface of the apron has been capable of almost completely eliminating any accumulation of loose fibers upon the fiber working machinery where the ribs of both classes of ribs intersect the longitudinal axis or edges of the apron at an angle which is less than 45 whereby the diamonds will be elongated in a direction transversely of the apron sleeve.
The invention thus generally described may be more clearly understood from the following detailed descrip tion of certain preferred embodiments thereof in connection with which reference may be had to the appended drawings.
In the drawings:
Figure l is a diagrammatic view of a fiber drafting apron according to the present invention employed in the Saco Lowell-Roth fiber drafting system.
Figure 2 is a fragmentary perspective in partial cross section of one preferred form of drafting apron according to the present invention.
Figure 3 is a plan view of the inwardly disposed surface of still another preferred apron according to the present invention.
Figure 4 is a similar plan view of the inwardly disposed surface of another apron according to the present invention.
Figure 5 is a perspective of a building mandrel for use in the manufacture of fiber drafting aprons according to the present invention.
Referring now to Figure 1, the strand or sliver 1 1 is shown to be passing through the bite of the rear drawing rollers 11 and 12, along the fiber contacting surface 1.: of the drafting apron 14 and then through the bite or mp of the front drawing rollers 15 and 16. The strand 10 may be held against the drafting surface 13 of the apron by intermediate rollers such as 17 and 18.
The drafting apron 14 forming the subject matter of the present invention is in the form of a flexible sleeve WhlCh would be normally cylindrical but is held in an elongated or extended position by means of the rollers 19 and 20 and the nose bar or forward supporting rod 21, these components being so spaced that the apron assumes the general shape of a triangle in passing around them. In the Saco Lowell-Roth drafting system of which Figure 1 is a diagrammatic illustration, the apron 14 is usually motivated by its contact with the roller 19 which is itself rotatably driven by suitable connection to the power or driving component of the drafting machinery. The guide roll 20 is rotatably mounted to be freely driven by the apron passing thereover, and the nose bar 21 is stationary. The apron slides over the nose bar which is smooth and polished at least at those surfaces which are contacted by the apron. To control the tension of the apron as it is supported by the rollers '19 and 20 and the nose bar 21 is the tension or idler roller 22 which is also mounted to rotate freely with the moving apron. The position of this roller 22 however, is controllably adjustable so that it may displace the apron from its normal path between its supports to achieve the desired tension for enabling the apron to maintain driving contact with the roller 19 and at the same time to pass smoothly over the guide roller 20 and the nose bar 21.
As explained above, it has been the problem in the case of all of the modern aprons of synthetic material that, as the apron continues to operate, loosely associated fibers begin to build up upon the surface of the nose bar 21 adjacent the edges of the apron and upon the parts of the idler roller 22 in contact with the apron. It can be seen that the fibrous mass accumulating on the nose bar is dangerously close to the sliver or roving being processed and could easily be drawn into the same. On the other hand, it can be seen that, as fibers build up upon the idler roller 22, the effective circumference or diameter of this idler roller will be increased so that it will displace the apron more than was desired or contemplated by the selective adjustment of the idler roller. As the apron thereby becomes increasingly tensed or stretched, it will either bind in passing about the rollers 19 and 20 and the nose bar 21 or will actually break. When the apron binds, not only will the drafting operation be disrupted but also the apron will be seriously damaged by the driving roller 19 which will continue to rotate against one portion only of the apron causing excessive wear at such point.
In order to solve these difficulties, the apron of the present invention is provided with a knurled or roughened inwardly disposed surface 23 which is characterized by a plurality of protrusions such as 24 projecting inwardly therefrom. 'Ihese protrusions may be in the form of ribs extending across the inwardly disposed surface 23 of the apron. As best shown in Figure 2, the ribs on the inwardly disposed surface 25 may be divided into two classes respectively designated by the numbers 27 and 28 wherein the ribs in each class are in parallel relationship diagonally of the apron and intersect the ribs of the other class which are similarly disposed. This intersection of the spaced, parallel ribs 27 and 28 respectively, results in the formation of a diamond pattern about the entire inner surface 25. Where the ribs of each class intersect the longitudinal axis or the edges of the apron at an angle which is less than 45, the diamonds 29 formed by their intersection will be flattened or elongated so that their greatest dimension extends substantially transversely of the apron sleeve. It will be noted that the ribs of both classes 27 and 28 intersect the edges or the longitudinal axis of the apron at the same angle so that the diamonds 29 are symmetrical about their longitudinal and transverse axes which are respectively longitudinally and transversely aligned upon the apron sleeve.
The ribs 27 and 28 are formed of the same material as that comprising the inwardly disposed surface 25 of the apron which in turn may be the same as or at least similar to the material of which the rest of the apron is composed. While, for the sake of clarity, the ribs have been shown to be relatively large, they are in fact of small cross section and where, for example, the over all apron thickness is on the order of .032 inch, the ribs themselves may measure approximately .005 inch or less in cross-sectional width and height. In one preferred embodiment of the present invention, it has been found that the ribs in each of the classes 27 and 28 may be spaced by from to of an inch; and in the case of an apron .032 inch thick wherein the ribs are .005 inch in height and width, a rib spacing of of an inch between centers has been found to prevent the above described undesirable formation of loose fibers either on the idler roller such as 22 or along the nose bar 30 at the edges 31 and 32 of the apron shown in Figure 2. One preferred angular disposition of the ribs so arranged has been found to be that which will result in the formation of diamonds which measure approximately 1.75 millimeters in their longer, transverse dimension and approximately l millimeter in their shorter dimension longitu' dinally of the apron.
In lieu of the criss-cross or intersecting ribs illustrated in Figure 2, it has been found that n'bs arranged in parallel and extending generally transversely as are the ribs 33 of the apron 34 in Figure 3 or extending longitudinally as are the ribs 35 of the apron 36 of Figure 4 will also substantially reduce the accumulation of fibers at the objectionable points in the fiber drafting machinery when an apron of synthetic material is employed.
Aprons according to the present invention may be formed in the conventional manner as for example that described in the United States Patent No. 2,341,656 issued February 15, 1944, to Joseph Rockoflf, wherein the layer or layers of synthetic material to form the apron body are wound about a mandrel and then compacted prior to vulcanization and final treatment. The ribs according to the present invention may be conveniently provided in such a method by employing a building mandrel having grooves or depressions therein corresponding to the protrusions or ribs ultimately desired in the finished apron. Such a mandrel is designated by the number 37 in Figure 5 wherein the outer periphery or building surface 38 is shown to have formed thereon a plurality of grooves 39 so arranged that when the grooves are filled with the elastomeric material forming the innermost apron surface, a ribbed surface similar to that illustrated in Figure 3 will result. The pattern of the grooves 39 may of course be altered to achieve either of the rib patterns shown in Figures 2 and 4 or any other desired arrangement of ribs or other protrusions. It will be understood that where a vulcanizable rubber or any other plastic elastomeric material is employed in the apron and particularly upon the innermost surface there of, such material may be brought to a state of plastic flow whereupon it may be molded to assume the surface characteristics of the mandrel and thereafter allowed to set so that such characteristics will be permanently fixed in the finished apron.
While the present invention has been described in considerable detail in connection with certain preferred embodiments, it is to be understood that such particul-arization and detail have been for the purpose of illustration only and do not limit the scope of the present invention as it is defined in the subjoined claims.
1. A fiber drafting apron in the form of a flexible sleeve having an outwardly disposed fiber-contacting surface and an inwardly disposed roller and nose bar contacting surface wherein said inner surface has a plurality of small parallel ribs extending longitudinally of said sleeve and projecting inwardly therefrom.
2. A fiber drafting apron in the form of a flexible sleeve having an outwardly disposed fiber-contacting surface wherein said inner surface has a plurality of small parallel ribs extending diagonally of said sleeve and projecting inwardly therefrom.
3. A fiber drafting apron according to claim 2 wherein said ribs are divided into two classes, the ribs of one class intersecting those of the other class forming a diamond pattern of ribs about said inner surface.
4. A fiber drafting apron according to claim 3 wherein said ribs form angles of less than 45 with the longitudinal axis of said sleeve.
5. A fiber drafting apron according to claim 4 wherein all of said ribs are disposed at an angle which is less than 45 to the longitudinal axis of said sleeve whereby the greatest dimensions of the diamonds formed by such ribs extends transversely of said sleeve.
6. A fiber drafting apron according to claim 5 wherein the ribs are spaced by from to V of an inch.
7. A fiber drafting apron according to claim 6 wherein the ribs in each of said classes of ribs are spaced by a distance of ,6 of an inch.
8. A fiber drafting apron according to claim 6 wherein said ribs are substantially .005 inch in height and width.
9. A fiber drafting apron in the form of a flexible sleeve having an outwardly disposed fiber-contacting surface and an inwardly disposed roller and nose bar contacting surface wherein said inner surface has a plurality of small parallel ribs projecting inwardly therefrom and forming angles of less than 45 degrees with the longitudinal axis of said sleeve.
References Cited in the file of this patent UNITED STATES PATENTS 1,028,783 Von Rabenau June 4, 1912 1,799,448 West Apr. 7, 1931 2,054,619 Freedlander Sept. 15, 1936 2,341,656 Rockoff Feb. 15, 1944 2,362,340 Bacon Nov. 7, 1944 2,686,939 Keyser Aug. 24, 1954