US 2911761 A
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INVENTOR ATTORNEY I Nov. 10, 1959 F. E. ANDERSON APPARATUS FOR CONTINUOUSLY TIPPING AND FLAGGING BRISTLES 2 Sheets-Sheet 1 Filed Oct. 22. 1958 Nov. 10, 1959 F. E. ANDERSON APPARATUS FOR CONTINUOUSLY TIPPING AND FLAGGING BRISTLES- Filed Oct. 22. 1958 2 Sheets-Sheet 2 z a F/ ATTORNEY "cries of the abrasive elements.
United States Patent Q APPARATUS FOR CONTINUOUSLY TIPPING AND FLAGGING BRISTLES Frederick Edwin Anderson, Parkersburg, W. Va, assignorto E. I. du Pont de Nernours and Company, Wilmington, Del., a corporation of Delaware Application October 22, 1958, SerialNo. 768,985 9 Claims. c1; 51- 80 This invention'relates to an apparatus for tipping and rflagging filaments of synthetic materials.
to further manufacturing operations to produce tips which simulate those-of animal bristles. The process of tapering the end of the bristle to a fine point is known in the industry as tipping, while the process of splitting the tips of the bristles to form" a plurality of hairlikepoints .at theend of a bristle is known as flagging.
A'complicating factor in the operations of tipping and flagging synthetic filaments is the diffieulty of handling loose filaments while attempting to perform operations on each filament. In the prior art, synthetic or natural bristles have been handled as a cylindrical bundle of loose bristles held in the form of a bundle by an encircling rubber band. In my earlier patent, US. 2,804,-
972, issued SeptemberB, 1957, there is described and claimed a novel method of packaging filaments by sewing a thin bed of filaments to a web of paper or other material to form a continuous belt of filaments. This novel package can be usefully adapted to the present process of tipping and flagging.
'It is an object of this invention to provide an apparatus capable of receiving a thin bed of filaments, which may or may not be sewn to a'tape in the form of a belt,
and continuously tipping and flagging those filaments for subsequent use as brush bristles. apparent from the detailed description and attached drawings explaining and illustrating this invention;
The above objects are accomplished by providing an apparatus comprising two rotatably mounted shafts supplied with means for rotating these'shafts at high speeds and in opposite directions; a multiplicity of thin abrasive elements mounted on each shaft, the abrasive elements being in the form of solid abrasive wheels, brushes made of abrasive bristles, or other abrasive assemblies ofsimilar configuration; a conveyor adapted to move a thin bed of filaments along a path parallel to, and in a plane substantially midway between, the axes of said shafts; means for clamping the bed of filaments to the moving conveyor, which, in turn, is positioned adjacent to periph- By means of this apparatus a bed of filaments, whether or not sewn to a tape to form a belt, is fed into the conveyor which clamps the midportion of the bed tightly to the conveyor while the flexible tips of the filaments are carried past two coacting, counter-rotating, high speedabrasive assemblies which taper-grind the ends of the filaments and flag the tapered tips. The abrasive elements may be in the form Other objects will be.
. Patented, Nov. 10, -1959 of solid abrasivewheels or discs, flexible abrasive bristles,
substantially inflexible abrasive rods,'or other-such-elements that maybe apparent tothose skilled:in thisv art.
The filaments being tipped may "be syntheticpolymer filaments, e.g. nylon,whether tapered or level, or they may be natural filaments, e.g...horsehair 'or .animal bristles; and furthermore, the filaments to be'itipped may be loose,-'sewn to atape as describedabove; mounted wheels.
" in the ferrule of a'paintbrushror.in.anyother-conceivable arrangement whereby. .thextips 'of the. filaments may be inserted into. the abrasive. elements of this apparatus to be tipped and flagged.
Tapered, synthetic filaments maybe prepared by'form- .ing .a continuous filament. having .regula'rly :zrepeating segments in which the diameter of the filamentchanges from a minimum to amaximum and back to a: minicontinuous filament. at .each :point of minimumLdiam- 'eter, filamentsegments are formed. By cuttingone of these segments at its midpointpwherethe:maximumrdrameter occurs, two individualatapered, synthetic bristles are formed. It may be seen that,:,as an alternative :ar-
'rangement of this apparatus; twopairs of abrasive wheels may be-positioned so asto :face each other, and may tip and flag, at the same time, each end of the filament segments in a-bed travelling past the abrasive wheels, after which those segments may be cut in halfhto form. two beds of individual bristles. "It is, of course, to be understood that this apparatus may be employed .totip and flag level filaments as well as tapered filaments. -:In' the attached drawings, Figure l-is a front elevation of one embodiment of the apparatus; Figure2 isacross-sectional view taken at A-A on Figure 1; Figure 3 isa top plan viewof-the apparatus .shown in Figure 1;- Figure 4 is a viewsimilar to that of Figure 2 except that the abrasive Wheels are substituted by brushes made of abrasive bristles; and Figure 5 is an isometric view of a sparsely populated brush which'may be used in place of the brushes shown in Figure 4.
Specifically referring to Figure 1, it may be seenthat the apparatus comprises two shafts, 1 and Zydrivenat high speed by a means which is not'shown so as to rotate in opposite directions with respect to each other. One suitable driving method would be to attach a motor'to shaft 2, turning the shaft in the direction indicated at=l-3, and transmitting the opposite rotation to shaft 1 th-ru spur gears 4. A series of thin abrasive wheels 5 are mounted on each shaft with a spacing between adjacent One suitable alternative for an abrasive 'wheel is a thin wheel brush with abrasive bristles or abrasive ma.- terials cemented to the bristles of the brush. The proper spacing may be supplied by the use of spacers 6. "Wheels 5 are afiixed to shafts 1 or2 and rotate with said shafts. The spacing between adjacent wheels 5 on a shaft is greater than the'thickne ss of a wheel so as to permit the wheels mounted on one shaft to extend into the spaces between wheels on the other shaft (shown generally at 7). The'mounting and spacing of wheels 5 are such that there is no contact between wheels. The spacing may be regular, asshown in Figure 1, or irregular. Any number of abrasive wheels 5 may be placed in series along shafts 1 and 2, limited only by the size of the apparatus. Another suitable alternative is to provide a cylindrical brush for each of the two shafts, 1.and'2, rather than a series of thin, wheel'brushes; and,.in the case of this alternative arrangement, the outer peripheries'of the two brushe-s'normally are substantiallytangent as shown in Fig. 4, rather than the overlapping arrangement of Fig. 2, although as described below some overlapping may beem ployed when using brushes as the abrasive assembly. Shafts 1 and 2 are, of course, mounted in suitable bearings shown schematically at 8 and 9.
By cutting the The foregoing part of the apparatus of Figure 1 comprises the grinding and flagging mechanism. The remainder of the apparatus is the conveyor system which moves the bristles or filaments, in the form of a continuous or intermittent bed, past abrasive wheels 5 in order to permit those bristles or filaments to be tipped and flagged. A continuous bed of filaments may be seen entering the apparatus from the right in Figures 1 and 3. This bed of filaments comprises, in its preferable form, a thin (not more than about inch thick) layer of filaments, oriented and aligned with each other in a direction which is generally perpendicular to the long axis of the bed and to the direction of travel through the apparatus for tipping and flagging. In the embodiment shown in Figures 1 and 3 the bed of filaments is attached to a paper tape by some form of stitching, e.g. by two rows of single-thread chain stitching. Such an article of filaments sewn to a tape is referred to herein as a belt, and it can be subjected to rather rough handling without disturbing the relationship of the filaments to the paper tape. It, of course, is not necessary to the operation of this apparatus that the tape be present since it merely affords a convenient way of handling the filaments entering and leaving this apparatus. Belt 10 is fed into a moving conveyor, such as that formed by the combination of chains 11 and chains 12. Other types of continuous or intermittent conveyors are useful in certain embodiments of this invention. Chains 11 and 12, in their movement from right to left, pass between clamping angles 13 and 14, which causes chains 11 and 12 to clamp belt 10 tightly between the chains as the filaments of belt 10 are passed into contact with wheels 5. Chains 11 and 12 are mounted on sprockets 15, which are driven in the directions indicated by arrows 16, such that the chains move in the same direction and at the same speed. Belt 10 leaves the apparatus at the left side of Figure l with one end of each filament having been subjected to the tipping and flagging action of wheels 5. Belt conveyors, or other known alternatives, may be used in place of chains 11 and 12.
The cross-sectional view shown in Figure 2 illustrates the positioning of the filaments and the abrasive wheels. The direction of rotation of wheels 5 is shown by arrows 17. Belt 10 is clamped tightly in place by chains 11 and 12, leaving the tips 18 of the filaments to be contacted by wheels 5 rotating at high speed. Clamping angles 13 and 14, preferably covered with a rubber-like strip 19, provide the force necessary to clamp belt 10 firmly to the moving chains 11 and 12. Support 20 provides a base onto which clamping angles 13 and 14 and sprocket shafts 21 and 22 may be attached. Driving means for rotating shafts 21 and 22 in the indicated directions are not shown. There does not appear to be any critical limit to the amount of overlapping of wheels 5 as viewed in Figure 2. The geometry and space requirements of chains 11 and 12, strips 19, and clamping angles 13 and 14 will determine the amount of overlap to be tolerated. As shafts 1 and 2 are moved apart, the distance between the top of angle 13 and the bottom of angle 14 must be made less and less in order that tips 18 may be placed in contact with wheels 5. Generally, about /2 to inch of the tip of the filaments in belt 10 should be placed in contact with wheels 5. If a greater amount of the filament tip is placed in contact with the wheels, the filament receives an excessive amount of grinding at some point above the tip. On the other hand, if a lesser amount of the filament tip is placed in contact with the wheels, the filament tip is ground to a rather blunt point.
All of wheels 5 may be replaced, in one embodiment of this invention with a cylindrical brush 25 on each of shafts 1 and 2, as shown in Figure 4. In such a case there is no overlapping as shown in Figure 2, but instead, the peripheries of the two brushes 25 just barely tong! or are separated by a very small clearance. The best filaments 18 which are being ground thereby may extend into the interior of the abrasive brushes.
In one particularly desirable embodiment there is employed a cylindrical brush which is sparsely populated with bristles as shown in Figure 5. The bristles are posit'ioned radially and spaced at equal angles from each other around the brush core, adjacent bristles being spaced apart from about 2 to about 45 as shown at 28. In the axial direction, adjacent bristles may be spaced any convenient distance, 29, depending upon the total length of the cylindrical brush. The bristles are preferably arranged in rows parallel to, and perpendicular to, the axis of the brush, thus forming a rectangular pattern, the distance between adjacent perpendicular rows normally being about the same as the distance between adjacent parallel rows. As an illustrative example, the brush core may be 2-3 inches in diameter with bristles extending 1-2 inches outward from the surface of the brush core. The spacing between adjacent bristles in a circumferential direction may be approximately 10 (measured at the center of the brush) while the axial spacing may be from about A; inch to 6 inch for brushes which are of a convenient length of about /2 to 2 feet. The brush bristles are generally rod-like in shape and may be wires; synthetic polymer filaments, e.g. nylon; natural animal hairs or bristles; reeds; rods; or the like. The abrasive character of the brush bristles may be achieved by coating a bristle with an adhesive and applying abrasive particles to the coating. The distance between the shafts on which these brushes are mounted is substantially the same as the outside diameter of the brushes, although a small amount'of overlapping, e.g. up to about inch, may be usefully employed by indexing the two coacting brushes so that, like the meshing of gears, the bristles of one brush mesh with the space between bristles of the other brush at the plane midway between the two shafts 1 and 2.
Figure 3 indicates the general arrangement of belt 10, wheels 5, and chains 11 and 12. Belt 10, moving in the direction of arrow 23, is moved by chains 11 and 12, clamped tightly by angles 13 and subjected to the opposed, intermeshing coaction of wheels 5. The tips 18 of the filaments are free to bend and flex, and are, therefore, subject to the abrasive action and the impact of each of wheels 5 as the conveyor chains carry belt 10 from right to left. The clearance 24 between adjacent intermeshing wheels should be as small as possible in order to conserve space, but clearance 24 should not be as small as the diameter of a single filament. Normally, if clearance 24 is about A; inch, both purposes will be adequately served. Wheels 5 are preferably made of a fine grade of abrasive material, such as carborundum. The abrasive particles are somewhat loosely bonded so that, as abrasive particles are torn loose, new, sharp particles. are exposed for further grinding.
As an illustration of the effectiveness of the apparatus of this invention, a belt of tapered nylon filaments approximately 6 inches long tapering from an average diameter of about 0.012 inch at the large end to about 0.008 inch at the small end was passed through an apparatus such as that shown on the attached drawings. The abrasive wheels were /1, inch thick by 7 inches in diameter. The spacing between wheels on the same shaft was about /2 inch, which, therefore, provided a clearance of about A: inch between adjacent intermeshed wheels, one from each shaft. The wheels were driven at'a speed of 3470 rpm. The belt of filamentswas driven at a linear spced of 15 inches per minute. After the filaments were subjected to approximately 5 minutes of such treatment, the tips of the filaments were examined by a microphotograph, which revealed that the taper differed from filament to filament, some being finished to a hair-like tip while other tips were not quite so finely ground. All filaments, however, exhibited the effects of being reduced in diameter by the taper-grinding, and substantially all of the filaments were split or flagged at the tip for a length of about one-sixteenth of an inch or less.
Even better results have been obtained using a pair of sparsely populated brushes as shown in Figure 5, as the abrasive elements for tipping and flagging tapered nylon filaments. The bristles of the brushes in one instance were nylon filaments, 1% inches long and 0.040 inch in diameter, coated with an epoxy adhesive and carborundum particles. In another instance wires, some what smaller in diameter than the nylon bristlw mentioned above, were employed with the same type of abrasive coating.
Many variations may be introducedinto the apparatus of this invention without departing from the spirit thereof, and this inventioon is not intended to be limited other than by the terms of the appended claims.
1. An apparatus for taper-grinding and flagging of filaments for subsequent use as brush bristles, which comprises two rotatably mounted shafts; means for rotating said shafts at high speeds in directions opposite to each other; each of said shafts having mounted thereon a multiplicity of thin abrasive elements such that all of the said elements on one shaft combine to form an abrasive assembly which is substantially cylindrical in shape; a conveyor adapted to move a thin bed of filaments along a path which is parallel to, and lies in a plane substantially midway between, said shafts; means for tightly clamping said filaments against movement with respect to said conveyor while leaving the filament tips which are to be ground free to flex and to bend, the individual filaments being aligned substantially perpendicular to the path of said conveyor; the distance between said shafts, the diameter of said abrasive assembly and the positioning of said conveyor being such that said filament tips are brought into contact with at least one of said abrasive assemblies throughout the movement of said bed along the entire length of said abrasive assembly.
2. The apparatus of claim 1 in which said abrasive assembly comprises a series of spaced, disc-like units having a diameter greater than the distance between said shafts; the units on one shaft extending into the spaces between, but not in contact with, the units on the other shaft.
3. The apparatus of claim 1 in which said abrasive elements are rod-like units extending radially from a cylindrical core to form a cylindrical abrasive assembly having an outside diameter substantially the same as the distance between said shafts.
4. The apparatus of claim 2 in which said units are I solid abrasive wheels.
5. The apparatus of claim 2 in which said units are brushes made of bristles comprising abrasive material.
6. An apparatus for taper-grinding and flagging of filaments for subsequent use as brush bristles, which comprises two rotatably mounted shafts, means for rotating said shafts at high speeds in directions opposite to each other, a multiplicity of thin abrasive wheels regularly spaced along each of said shafts, the wheels of one shaft being staggered with respect to the wheels of the other shaft and being positioned such that the wheels of one shaft extend into the spaces between, and not in contact with, adjacent wheels of the other shaft, a continuous conveyor adapted to move a thin bed of filaments along a path which is parallel to, and lies in a plane passing midway between, said shafts, means for tightly clamping the central portion of said filaments against movement with respect to said conveyor, while leaving the tips of said filaments free to be bent, said conveyor being positioned sutficiently close to the periphery of said wheels so that the tips of the filaments being held by said conveyor are in contact with said abrasive wheels.
7. An apparatus for taper-grinding and flagging brush bristles assembled in the form of a continuous belt comprising a thin bed of bristles placed in side-by-side alignment and sewn to a narrow continuous tape positioned along the longitudinal axis of said beltgsaid apparatus comprising two opposed, continuous conveyors adapted to press against opposite sides of the central portion of said belt of bristles and to transport said belt in a longitudinal direction; means for driving said conveyors in the same direction and at the same speed; two rotatably mounted shafts driven so as to rotate in opposite directions with respect to each other; a multiplicity of thin abrasive disc-like wheels aifixed to, and regularly spaced along, each of said shafts, the spacing between adjacent wheels being approximately twice the thickness of one of said wheels; the peripheries of the wheels of one shaft extending into the spaces between adjacent wheels on the other shaft; said belt and the conveyors transporting said belt being positioned midway between, and parallel to, said shafts and in close proximity to the peripheries of said abrasive wheels whereby the tips of said bristles brush into contact with each of said wheels while being transported by said conveyors; said wheels being driven at a high speed in a direction toward said bristles.
8. An apparatus for taper-grinding and flagging syn thetic polymer filaments assembled in the form of a continuous belt comprising a thin bed of filaments placed in side-by-side alignment and sewn to a narrow continuous tape positioned along the longitudinal axis of said belt; said apparatus comprising two opposed, continuous conveyors adapted to press against opposite sides of the central portion of said belt of filaments and to transport said belt in a longitudinal direction; means for driving said conveyors in the'same direction and at the same speed; two rotatably mounted shafts driven so as to rotate in opposite directions with respect to each other; a cylindrical brush fixedly mounted on each of said shafts and being made of abrasive bristles, the diameter of each of said brushes being substantially the same as the distance between said shafts; said belt and the conveyors transporting said belt being positioned midway between, and parallel to, said shafts and sufficiently close to the perpiheries of said cylindrical brushes that the tips of said filaments are contacted by said abrasive bristles; said cylindrical brushes being driven at high speed in a direction toward said filaments.
9. The apparatus of claim 8 in which said abrasive bristles are lengths of metallic wire coated with abrasive particles, and in which those bristles are arranged in a regular pattern of rows such that, in any cross section perpendicular to the axis of the said brush, the bristles are equally spaced around the brush at an angle between adjacent bristles of 2-45, measured at the center of the brush.
References Cited in the file of this patent UNITED STATES PATENTS 1,078,507 Loomis Nov. 11, 1913 1,495,747 Izawa May 27, 1924 1,627,704 Izawa May 10, 1927 1,888,675 Izawa Nov. 22, 1932 2,017,487 Elliot Oct. 15, 1935 2,227,126 Cooke Dec. 31, 1940 2,365,396 Cunningham Dec. l9, 1944 2,854,797 Van Clief Oct. 7, 1958