US2035521A - Granular coated web and method of making same - Google Patents

Description

March 1936. R. c. BENNER ET AL A 2,035,521

GRANULAR COATED WEB AND METHOD OF MAKING SAME Filed Oct. 26, 1932 2 Sheets-Sheet l O IF 13 O i J INVENTORS RAYMOND G, BENNER QOVHE L. MELTON y HENRY 9 K\RGHNER ATTORNEY GRANULAR COATED WEB AND METHOD OF MAKING SAME Filed Oct. 26, 19:52 2 Sheets-Sheet 2 INVENTORS RAYMOND QBENNER ROMHi L MELTON BY HENRY P KlRCHNER ATTORNEY Patented Mar. 3,1, 1936 UNITED STATES PATENT OFFICE GRANULAR COATED wan AND METHOD F MAKINGYSAME Application October 26, 1932, Serial No. 639,598

4 Claims.

This invention relates to the manufacture of granular coated webs, such as abrasive paper and cloth and various nonabrasive granular coated Products.

Granular coated webs, as they have been made in the past, have had surface coatings of granular material without particular order in position or orientation. In other words, the granules have not been arranged on'the web but have been haphazardly deposited thereon. The granular material was fed by gravity'onto the adhesive coating and, as a result, the particles assumed positions flat on the web. With such arrangement, or rather lack of arrangement, it has not been possible to secure the-maximum efficiency of abrasion because a great many of the particles were so positioned that their sharper edges were not in positions whereby they could engage the Work.

20 v More recently it has been proposed to make abrasive coated webs by arranging the particles on the web in such fashion that the major axes of a substantial proportion, of the particles are normal to the surface of the web. ,An abrasive faster than the previously known abrasive webs because a large proportion of the particles of the formerly known type of web were embedded fiatwise in the adhesive and consequently were of limited use in abrading, whereas particles arranged in such a, manner that their major axes are normal to the surface of the web are also so positioned that they presentsharp cutting points or edges to the material undergoing abrasion;

We have found that superior coated webs can be produced by so positioning the granular material that a substantial proportion of grains are individually oriented and inclined with their longer dimensions at an oblique angle with respect to the surface of the web. Such an inclination of the grain causes each particle to dig into the surface of the substance being abraded, when the abrasive articleis moved with respect to the work, or vice versa, in somewhat the same general manner as the inclined teeth of a saw dig in and turn up a chip. This tendency of the abrasive particles to dig into the work surface causes faster abrading action, yet the abrasive particles are so positioned that-they are not readily torn from the web as is the case when they are arranged normal to the surface of the web.

One method by which coated webs having the abrasive granules arranged on the surface at an oblique angle to the surface of the web can be made consists essentially in so positioning the coated web of this nature has'a tendency to cut web after it has received a coating of adhesive and a coating of granular particles arranged with their major axes normal to the surface of the web, that the granular particles hang downward while the web itself is inclined at an oblique angle 5,

with respect to the vertical. The adhesive, being freshly applied and therefore not hardened or set, permits gravitational attraction to cause the particles to rotate about their attached ends until they hang downward in a vertical direction. 10 By causing the coated web to remain in this position until the adhesive has acquired at least a partial set, whereby the granular particles become fixed in position, the particles can be arranged on the web so that substantially all of i5 them are at an oblique angle with respect to the surface of the web.

Arrangement of the particles normal to the surface of the web can be accomplished by blowing them with a blast of high velocity,low volume air from a screen upwardly to a web having its adhesive coated side downward. The particles, as they move upwardly with the assistance of the air blast, orient themselves so thatthey strike. the adhesive coated web in endwise fashion and therefore project substantially normally from the adhesive coated web; Our copending application, Serial No. 647,241 filed December 14, 1932, discloses and-claims this method of projecting the particles upwardly by means of, a blast of high velocity, low volume air.

Another way in which the particles can be caused to be arranged at an oblique angle with respect to the surface of the web consists in moving a web with a fresh coating of adhesive and granular particles arranged substantially normal to the surface thereof into contact with a roller rod so positioned that it gently tips the particles over to the desired angle with respect to the surface of the web. Inasmuch as this step 40 must be carried out while the adhesive still is soft and unset, it is desirable to position the web after the particles have been'tipped over in such a manner that the particles hang down vertically while the web is at anoblique angle with respect to the vertical, and to hold it in such a position until the adhesive has acquired at least a fitmness suflicient to-prevent further movement of the particles with respect to the surface of the web.

While the previously mentioned methods of positioning the granules on the surface of the web have involved as a first step 'thedeposition of the grains normal to the surface of the web, the same resu t can .be accomplished by depositing the grains on the adhesive coated web at the angle desired without first orienting them normal to the web. This can be done by so positioning the means for holding the adhesive coated web and the means for projecting the granular material that the particles are deposited on the adhesive coated web at the desired angle. A better understanding of this phase of our invention can be had by reference to the accompanying drawings, in which:

Fig. 1 is an enlarged side view of the usual granular coated article,

Fig. 2 is an enlarged side view of a granular coated article made in accordance with this invention,

Fig. 3 is a diagrammatic side elevation of a sanding device utilizing an abrasive belt made in accordance with the present invention,

Fig. 4 is an enlarged sectional view of a portion of Fig. 3,

Fig. 5 is a diagrammatic side elevation of one form of apparatus, and

' Fig. 6 is a section along. the line II-II of Fig. 5.

the usual method of coating abrasive webs and that of articles made according to our invention, is illustrated in Figs. 1 and 2, respectively. The grains 2 in the previously known articles, as shown in Fig. 1, do not have their sharpest surfaces projecting at an angle with respect to the plane of the web, and therefore, are not free for the abrading action. On the other hand, as shown by the side view of an abrasive coated web made in accordance with our invention, as illustrated in Figs. 2 and 4, thegrains 4 are oriented and inclined so that their sharpest or needle-like points form the abrading surface, and when moved in the direction indicated by thearrow 6, dig into the work surface and therefore out faster than the previously known abrasive paper.

Abrasive coated webs made in accordance with our invention have been found to possess excellent abrading characteristics. When the granular particles are uniformly inclined in the direction of movement of the web, they readily dig into the surface of the work piece and thus increase the cutting rate of the abrasive.

Abrasive coated webs of widely different characteristics can be secured by making articles having different degrees of angularity between the granular particles and the backing. Those coated webs with the grains at a small angle of inclination tend to penetrate the Work surface. to a greater degree than those with a larger angularity. It usually is advisable to make the angle of inclination of the granular particles from about to about 75 with respect to the surface of the web.

The cutting action of an abrasive coated web. made in accordance with the present invention. is illustrated in Figs. 3 and 4. Referring to Fig. 3, an abrasive belt 8 having an inclined granular coating is carried by the driving roll or pulley l0 and the idler roll II. This abrasive belt is held in contact with the work piece I2 by themember 13, which also provides a means for applying pressure indicated by the arrow F, to the back of said belt. The work piece I2 is supported on a table I4, which is vertically adjustable to compensate for varying thicknesses of the work piece.

When the abrasive belt 8 is moved in the direction-indicated by thearrow 6, the points of thegranular particles 4 engage the surface of the work piece l2 at an angle and more readily penetrate the surface thereof. As illustrated by the enlarged view in Fig. 4, the inclinedgranular particles 4 cut or dig into the surface somewhat in the fashion of a farmer's plow making a furrow in the surface of the earth, since the long granular particles are relatively sharp at the points.

A further advantage lies in the fact that the twisting or turning movement of the particles about their bases, which is produced by the resistance of the work surface to abrasion, is greatly reduced because the particles penetrate more easily. This is a marked improvement over other types of abrasive web, such as those recently proposed, in which the granular particles are oriented perpendicularly to the plane of the work surface.

Since abrasive webs with the grains arranged at an oblique angle, as described above, possess different cutting properties, depending upon the relative direction of motion between the abrasive coated web and the work surface, we have found that certain desirable results can be obtained by causing relative motion in a direction opposite to that by which the particles dig into the work. When the motion is in a direction opposite to that illustrated in Figs. 3 and 4, the inclined granular particles make an angle less than 90 with respect to the unabraded surface, and polish the work surface rather than rapidly abrade it. Less stock is removed from the material being abraded by this method, but the resulting surface is smoother and approaches that of a polished surface. Thus, by reversing the relative direction of movement of the abrasive belt, illustrated in Fig. 3, the same rapid cutting abrasive belt can be used for a finishing operation in which it is desired to remove a very small amount of material and produce a polish or high finish.

Referring to Fig. 5, which illustrates apparatus for producing coated webs embodying our in vention, there are shown means A for holding and dispensing a roll l6 of the web P which may be of paper, cloth or the like, and which, for

purposes of brevity, will herein be referred to as the web; means B for applying adhesive to one side of the web P; means C for applying granular material to the adhesive side of the web P at a predetermined angle thereto; means D for caus- &

ing a preliminary set of the adhesive; and means E for drawing the web through the coating apparatus and into a drying chamber.

The means A for holding and dispensing the web P comprises, as shown in the drawings, a

frame I! that supports the roll l6 of web P; an idler roll l8 for guiding the web; printing rolls l9 and for marking the web with any desired legend or identification; and an idler roll 2| for guiding the web.

The adhesive applying means B comprises, as shown in the drawings, idler rolls 23 and 24 for guiding the web; a roll 26 positioned to dip into apan 21 of adhesive; a roll 25 for maintaining contact between the web P and the roll 26; adrum 28 and an adhesive distributing brush 29 positioned above the saiddrum 28; and anidler roll 30 for guiding the web as it is brought from the adhesive distributing brush.

Means C for applying granular material to the web P comprises, as shown in the drawings, an idler roll 32 which is both horizontally and vertically adjustable, as shown, for guiding and positioning the web; agrain hopper 33 with anadjustable gate 34 and a, roll 35 for dispensing the (ill the web P. The combination of the grain projecting means and web positioning meansis representative of apparatus herein referred to as orienting means-.

The means D for causing the adhesive to acquire a preliminary set comprises, as shown in the drawings, an adjustable idler roll and asource 4| for supplying a large volume of air at a low velocity to the adhesive and granular coated side of the web P.

The means E for drawing the web, P from the coating apparatus into the drying chamber comprises, as shown in the drawings; one or more suction drums 43 and 44; an idler roll a rack 41 for supporting the web P; and an endless conveyor 46 for transporting loops of the web P tothe rack 41. u

" In the normal operation of the apparatus illustrated in Fig.5, a roll of the uncoated, web P, such as paper or cloth,- is rotatably mounted on the frame I1 and the web is threaded over the roll I8 and between the printing rolls l9 and 20,

thence in contact with the idler rolls 2|, 23 and 24 to the pressure roll 25 and the adhesive roll 26. The adhesive roll dips into liquid adhesive contained in theadhesive tank 21, and on the upward-movement of travel of the roll 26, a layer of adhesive is applied to .the web. I i

The adhesively coated web P passes betweenth brush drum '28 and a vibrating brush 29 which evenly distributes the adhesiveand smoothes out any ridges. It is then guided by theidler roll 30 and adjustable roll 32 past the grain projecting apparatus 31. t

Granular particles are distributed from thegrain hopper 33 onto the grain projecting means 31, shown in section in Fig. 6, and upon traveling down this chute, the elongated particles are oriented by the channels so that their longer axes are parallel to the direction of motion. After leaving the end of the grainprojecting means 31, the particles strike the adhesive coated surface of the web P and become embedded therein.

Immediately after being coated with granular material, the web P is made to turn upward past the roll 32, over thefan blower 4|, and toward roll 40, the angularity' of the web being so adjusted by the positioning of the roll 40 that the granular particles are substantially vertical. The web is maintained in this position until the adhesive has acquired at least a partial set by the action of the air from theblower 4|, whereupon it may be moved in any direction desired without disturbing the orientation of the granular particles. By positioning the web at an angle whereby the grains hang downward, the force of gravity not only operates to preserve orientation, but to promote orientation by causing the particles to turn to a vertical position.

Orienting means, one form of which is illustrated in the drawings, consist essentially of a combination of means whereby the grains and the web are brought toegther in such fashion I and has no axis susceptible to orientation. "Such grain, of course, can not be oriented advantageously, but it does contribute to fast cutting characteristics of the web because it is projected onto the web at an oblique angle and therefore becomes positioned on the web in much the same manner as those grains that are of the elongated type. r

, Abrasive granular-material as received usually consists ofa mixture of elongated and blocky grains, the proportions of which will vary depending upon the composition of the grain and also on the kind of apparatus used in reducing the crude material to smaller sizes. While our apparatus will, orient the elongated particles that occur in the usual granular material, andwill position the blocky type in somewhat the same way, we usually find it desirable to separate the two types, selecting grains, containing at least a 7 Whonabrasive coated webs embodying our 7 invention are moved in contact-with the material undergoing abrasion in such manner, that the particles dig into the material, or in other words, so that the angle between the unabradedsurface of the. material and the major axes oi the granular material is greater than 90, the abrading process can be carried on with a greater efliciency than has been known heretofore. Each particle acts in a manner similar to the blade of a carpenter's plane and thus disengages from the mass of the material being abraded, a portion more like a shaving than the usual particle which resembles and is called;dust. The plane-like action of each grain on a web embodying ourv invention increases the eiiiciency of the abrading operation because the arrangement of the grains and the direction that the grains are moved with respect to the material being abraded permit ing a fibre or a group of fibres from the main body of the wood, and since the arrangement of the grains and the direction that they move with respect to the material being abraded permits each abrasive grain to penetrate more deeply into the wood with the same expenditure of energy, it becomes obvious that a group of fibres can be removed from the main body with no greater expenditure of energy as is required to remove a fibre or a portion of a fibre by the use of the abrasive coated webs known heretofore. Thus, the amount of work required to remove a unit volume of material is less when done with an abrasive coated web embodying our invention in the mannerdescribed herein.

usual dragging action inherent in the use of the previously known abrasive coated webs. Another advantage that contributes tothe greater efficiency in the use of abrasive coated webs embodying our invention results from the fact that the abrasive particles are not subjected to the same tearing out action that is inherent in the use of the abrasive coated webs heretofore known. Since theparticles on the surface of a web embodying our invention penetrate the work and remove a portion thereof with less expenditure of energy, it is obvious that they will remain attached to the web for a longer period of time than will the grains on the coated abrasive webs known heretofore.

When the abrasive particles are arranged on the web so that their major axes are at an oblique angle with respect to the, surface of the web, they abrade with less chattering than when the particles are arranged with their major axes normalto the web. This is brought about by the fact that the oblique particles penetrate the work more readily, whereas the particles arranged perpendicular to the web have more of a tendency to drag across the surface and as they drag they intermittently penetrate the work. This intermittent penetration has the tendency to set up vibrations or chattering, which causes the particles to become loosened, and therefore easily removed from the web.

Other advantages will be apparent from the foregoing disclosure to those skilled in the art and while specific embodiments have been used to illustrate our invention, it is to be understood that the invention is not limited to those embodiments but is defined by the appended claims.

We claim:

1. In the manufacture of granular coated webs, the method comprising positioning elongated granular particles upon an adhesive coated web, with the major axes of the particles at an angle of less than 180 with respect to the surface of the web, and supporting the freshly coated web at an oblique angle with respect to the horizontal and with the coated side down until the adhesive has acquired at least a preliminary set.

2. In the manufacture of granular coated webs, the method comprising positioning elongated granular particles upon an adhesive coated-web, with the major axes of the particles at an angle of less than 180' with respect to the surface of the web, orienting substantially all of the particles with their axes parallel and at an oblique angle with respect to the surface of the web, and supporting the freshly coated web at such an angle with respect to the horizontal that the oriented particles hang vertically downward until the adhesive has acquired at least a preliminary set.

3. As a new article of manufacture, a granular coated web in which a substantial proportion of the granular particles are uniformly oriented with their longer dimensions inclined at an oblique angle with respect to the plane of the web.

4. As a new article of manufacture, a granular coated web, a substantial proportion of the;

granular particles of which are of an elongated character, said elongated particles being so oriented that their longest dimensions are inclined at an oblique angle with respect to the surface of the web.

RAYMOND C. BENNER. ROMIE L. MELTON. HENRY P. KIRCHNER.

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