US3281882A - Brush type rotary tools and the like - Google Patents

Description

Nov. 1, 1966 v. K. CHARVAT 281,882

BRUSH TYPE ROTARY TOOLS AND THE LIKE Filed Feb. 27, 1964 2 Sheets-Sheet 1 INVENTOR. VZ RNM/KT ('HARVA T BY Nov. 1, 1966 v. K. CHARVAT 3,281,882

BRUSH TYPE ROTARY TOOLS AND THE LIKE Filed Feb. 27, 1964 2 Sheets-Sheet 2 INVENTOR. Vlmmom KT 611,412 VA T 3,281,882 BRUSH TYPE ROTARY TOOLS AND THE LIKE Vernon K. Charvat, Bay Village, ()hio, assignor to The Osborn Manufacturing Company, Cleveland, Ohio, a corporation of Ohio Filed Feb. 27, 1964, Ser. No. 347,754 6 Claims. (Cl. 15-479) This application is a continuation-in-part or my prior co-pending application Serial No. 834,091, filed August 17, 1959, now Patent No. 3,129,269.

The present invention relates generally to brush type rotary tools, and more particularly to power driven rotary brushes having plastic intruded into the body of brush material to support and regulate the action of the latter, 'but the product may also find utility for other purposes including use as a supporting or traction wheel for various types of vehicles.

As shown in Peterson Patent No. 2,826,776 and Stingley Patent 2,950,495, it has heretofore been proposed to make brushing tools of various types by combining with brush bristle material a body of plastic or resilient elastomeric material, and a number of such plastic materials have been employed including natural rubber and various kinds of artificial rubber, and synthetic resins such as polychloroprene which may be afforded a cellular structure by incorporation of suitable gas forming ingredients therein. Particularly suitable plastic materials for the purpose are the polyurethanes, including polyurethane rubber, these being relatively liquid when incorporated while the constituents are yet incompletely reacted. However, in all cases there has remained the difficult problem of introducing the selected material between the brush bristles so as uniformly to coat the latter and fill the spaces therebetween. The problem is particularly acute where the brush bristle are of relatively fine filamentous form or lack sufi'lcient stiffness so that they may become easily disarranged and tangled.

One of the principal objects of the present invention is accordingly to provide brush type rotary tools and like articles wherein centrifugal force is utilized to distribute the plastic material between the brush bristles while at the same time the latter are effectively maintained in desired position and spaced apart relationship. As a result of employing this method, a product is obtained of exceptionally uniform and balanced construction with a brushing face of uniform density and bristle tip concentration.

Another object of the invention is initially to distribute the plastic material in a region adjacent the outer working ends of the brush bristles and then to cause such plastic material to foam not only to produce a cellular structure in the finished article but also to cause such plastic material to expand inwardly toward the basal ends of the brush bristles in a direction generally longitudinally of the latter, thereby etfecting thorough and uniform intrusion of the plastic material without any tendency laterally to compact the body of brush bristle material.

Still another object is to intrude plastic or other material into the body of brush material of a power driven rotary wheel type brush wherein such intruded material is caused to flow radially inwardly from an outer annular region encompassing the brush face so that such material is intruded substantially longitudinally of the radially disposed bristle or like elements.

A further object is to provide a novel brushing tool in which the brushing elements such as hard straight wire bristles or soft flexible cord, for example, extend substantially directly radially in a uniformly spaced manner with a resin or plastic material, usually foamed, therebetween.

ited States Patent Other objects of the invention will appear as the description proceeds.

To the accomplishment of the foregoing and related ends, said invention then comprises the features hereinafter fully described and particularly pointed out in the claims, the following description and the annexed drawing setting forth in detail certain illustrative embodiments of the invention, these being indicative, however, of but a few of the various ways in which the principle of the invention may be employed.

In said annexed drawing:

FIG. 1 is a semi-diagrammatic axial end view of a brush type rotary tool or wheel made in accordance with my invention;

FIG. 2 is a diametral transverse section of such tool or wheel taken on the line 22 on FIG. 1;

FIG. 3 is a diagrammatic elevation partly in vertical cross-section of a circular mold mounted upon a turntable or centrifuge adapted for the production of a rotary tool or wheel of the type generally illustrated in FIGS. 1 and 2, the brush component of such wheel being shown properly located in the mold.

FIGS. 4-9 inclusive are diagrammatic detail views similar to FIG. 3 illustrating successive operative stages in the production of the new composite brushing tool or wheel;

FIG. 10 is a transverse section similar to FIG. 9 but showing the tool as formed with a non-foaming plastic composition; and

FIG. ll is an axial detail view on an enlarged scale of the spider or adapter which I may employ to center an annular rotary brush element within the mold during the centrifuging operation.

The brush type rotary tool or wheel illustrated in FIGS. 1 and 2 of the drawing is illustrative of the various products of this invention. In such illustrative embodiment, the tool or wheel comprises an annular rotary brush section which may, for example, be of the type disclosed in Whittle Patent 2,288,337 having an annular channel back 1 in which radially outwardly extending bristles 2 are secured, and an annular body 3 of plastic intruded between and embedding such bristles. The plastic may preferably but not necessarily be a resiliently dcformable cellular composition and foamed polyurethane is a preferred material for the purpose.

One or more of such annular brush sections may be assembled in axially aligned relationship within an appropriate mold (FIG. 3), or, for example, helically wound brush strip such as that shown in Peterson Patent 2,363,386 may similarly be employed. Such mold may desirably comprise an annular outer ring 4 adapted to be centered and clamped bttween lower and upper face plates 5 and 6 respectively, the assembly being thus clamped together by means of nut 7 on central threaded stud 8.

The annular brush section may be centered within the mold thus formed by means of a spider 9 which may be sheet metal stamping of the form illustrated in FIG. 11 having a central opening 10 and a plurality of radially outwardly extending legs such as 11 terminating in axially ofiset portions such as 12 which serve to engage the inner periphery of the annular channel back 1, opening 10 fitting over central stud 8. The over-all diameter of the brush section will preferably be somewhat less than the inner diameter of mold ring 4 so as to provide an annular space between the ends of the bristles and the mold. When a foamable plastic material is to be used to fill the brush, the stud 8 will also desirably be provided with a central vent passage 13 therethrough communicating with the interior of the mold.

In a typical operation, a foamable fiowable plastic material may be discharged in predetermined quantity from container 14 into the open mold wherein the annular brush section has been centered, such mold being mounted on a turntable or centrifuge 15 for rotation about the vertical axis of stud 8. After such measured charge 16 has been thus deposited in the mold generally centrally thereof as shown in FIG. 4, the cover plate 6 is placed in position and secured by means of nut 7. The mold may thereupon be rotated at sufficiently high speed to produce effective centrifuging action, e.g. at 3,000 r.p.rn. for 45 seconds when employing the preferred polyurethane composition to cause the plastic charge 16 to flow radially outwardly of the end faces of the annular brush section to the annular space between the brush bristle ends and the inner peripheral surface of mold ring 4, the plastic material thereupon flowing radially inwardly between the bristles until a condition of substantially dynamic balance is achieved as shown in FIG. 6. As the polyurethane constituents continue to react, the plastic charge 16 gradually becomes less liquid and more viscous and at this stage rotation of the mold will be stopped or very substantially reduced to encourage foaming of the plastic charge in this condition as shown in FIG. 7. Such foaming action, of course, serves to expand such plastic charge radially inwardly of the mold with further intrusion of the plastic material between the brush bristles, the direction of such expansion being such that the proper uniform spacing of the bristles remains substantially unaffected thereby. Air and other gases may escape from the mold through the aforesaid vent passage 13 in central stud 8. The charge may be of such precisely predetermined volume that it will fill the mold only to the extent illustrated in FIG. 8 and after proper curing, the finished article may be removed therefrom and separated from the spider or adapter 9. More generally, the foaming plastic material will be employed in such quantity as to fill the mold completely as shown in FIG. 9. When the molded article is then removed, it may be mounted upon an arbor or mandrel of the same diameter as stud 8 for use, or the center portion including the spider 9 may be punched out and the resultant article (as shown in FIG. 1, for example) mounted upon an appropriate arbor or adapter of the same diameter as that of the inner periphery of the annular channel brush back 1.

Now referring more specifically to FIGS. 1 and 2 of the drawing, the embodiment of the invention there illustrated also includes annular ribs 17 and 18 of plastic material integral with the plastic material with which the brush is filled, such ribs being molded on the respective end faces of the tool and spaced inwardly from the working face of such tool a substantial distance which may be on the order of about one-third of the radial extent of the annular body of the tool. Such ribs strengthen the wheel and assist in limiting deep radial tearing of the cellular plastic or resin between the bristles in use. Such ribs are, however, ordinarily not essential. In view of the fact that the outer ends of the brush bristles 2 were spaced inwardly from the inner peripheral surface of the mold, there will be an outer circumferential layer of foamed plastic material on the working face of the tool. Such layer will, however, promptly be eliminated upon placing the tool in operation or may desirably previously be removed by engagement with an appropriate power driven rotary wire brush.

When a non-foaming resin is employed to fill the brush, a larger charge will, of course, ordinarily be deposited in the mold which may be rotated to facilitate filling of the mold. The cover plate 6 may then be applied and the mold rotated at high speed to cause the plastic material to flow radially outwardly across the respective end faces of the brush element to the annular space between the bristle ends and the inner peripheral surface of ring 4 and then radially inwardly between such bristles until a condition of dynamic equilibrium is reached. The plastic material will ordinarily be caused at least partially to gel, as by application of heat, before removal of the composite tool from the mold, although when employing some relatively viscous fluid filler materials which adhere tenaciously to the brush bristles and do not tend to drain rapidly from the latter, the treated brush section may sometimes be promptly removed from the mold for drying, curing or setting.

When the brush material is highly flexible or even limp in character, as in the case of certain types of cord, fine wire, glass fiber and the like, it will ordinarily be important at least partially to set the plastic material prior to cessation of the centrifuging operation, this for the reason that the centrifugal action is relied upon to hold such brush material in proper radially extended condition during intrusion and setting of the filler material. Even when using rather stiffer bristle material such as a mixture of steel wire and tampico fiber, for example, such centrifugal action is highly advantageous in maintaining proper desired orientation of the bristles during intrusion of the plastic material and until the latter has at least partially set. As will thus be seen, the centrifugal action brings the bristles into rotary dynamically oriented relationship in substantially true radial positions, and the plastic material intruded between the bristles maintains them spaced apart in such dynamically oriented positions.

As may be deduced from the foregoing, a wide variety of brush material may be utilized in accordance with the present invention, depending upon the characteristics of the resultant brushing tool desired. Thus, relatively hard brittle steel wire bristles having a Knoop hardness in excess of 600 and even in excess of 800 may desirably be employed to produce a composite tool having rapid cutting action on the work, a foamed e-lastomeric polyurethane composition being intruded between such bristles to damp vibration and support the same. The brush material may, on the other hand, comprise vegetable fiber such as tampico fiber and sisal, glass fiber which may be either in the form of relatively stiff hard monofilaments or relatively soft fine stranded cords, plastic filaments such as nylon monofilaments, copper wire, stainless steel wire and the like. The brushing material may also be in the form of a porous fibrous batt comprising a mass of filamentous or fibrous material such as chopped tampico fiber bonded together by a suitable adhesive, the foamed plastic filler material being intruded therein in the same manner described above in the case of a more conventional rotary brush section.

Suitable granular abrasives such as aluminum oxide, silicon carbide, pumice and rouge may be incorporated in the plastic filler material and thereby intruded into the brush for application to the work as the brush face wears back in use. Such granular abrasive thus incorporated in a cellular plastic structure is made available at the working face of the tool when needed, but in the meantime is held in a manner which prevents destructive action of the abrasive upon the brush filaments themselves.

As well shown in FIG. 2, the method of manufacture above described also usually results in the formation of a thin plastic skin on the axial end faces of the resultant composite tool which considerably reinforces the latter. Even when a foaming plastic composition is employed, such skin will ordinarily be relatively smooth and impervious. It is generally preferred that the cells formed by the foaming operation not be in communication with one another, but rather that the product be of the closed cell type as there will then be little or no tendency of the tool to absorb liquids under conditions of use which might deleteriously aflfect the structure and cause undesirable imbalance of the wheel when rotated at high operating speeds. While rotary brush sections having annular metal backs may frequently constitute a preferred component of the new composite tool, it is not essential that such annular back-s be employed and the brush material may simply be doubled about an annular ring in wellknown manner, or no retaining element at all may be utilized as in the case of the porous batt of fibrous material mentioned above. Similarly, the brush bristle material may simply be distributed radially within the mold with the inner ends thereof being bonded together by means of a suitable adhesive or by interfusion of such ends as when plastic bristles such as nylon are employed. Particularly good results are obtained when practicing the method of this invention and utilizing beaded bristle material of the type disclosed and claimed in my copending application Serial No. 86,378, filed February 1, 1961, for Brush and Brush Material, now Patent No. 3,090,061.

While the hereinafter described polyurethanes are ordinarily preferred for my purpose, certain other plastic compositions or resins may be utilized in achieving some of the benefits of my invention; for example, phenolic, epoxy, natural rubber, polyisoprene, butadiene-styrene, butadieneacrylonitriile, and polyvinyl chloride resins, especially foams. Abrading wheels of epoxy resin foam and abrasive, and wheels of vinyl plastisol and abrasive are especially useful for some purposes.

Among presently available compositions, I prefer to employ as the elastomeric material to form the body one of the isocyanate resins, known as polyurethanes, which are formed by the reaction of the diisocyanate (usually toluene diisocyanate) with a polyester and/or polyether, the result of the reaction being the formation of a long chain polyurethane. The addition of water (and/ or acid) to the reaction mixture causes cross-linking of the polyurethane chains, releasing carbon dioxide which serves as a foaming agent.

The reagents, and in particular the polyester, employed in making the foamed polyurethane elastomeric body will vary depending upon the degree of resiliency or rigidity and other characteristics which it is desired such body should possess. For the polyester, one of the series currently marketed by American Latex Products Corporation, of Hawthorne, California, under the trade name Stafoam has been found satisfactory. One of the 300 Series products under this trade name, more specifically one of such series containing at least one or more benzene rings, will produce a relatively rigid body. The following is another formulation using a resin sold by Nopco Chemical Company under the trade name Lockfoam which will produce a resilient wheel:

189 grams A-516-R Lockfoam resin manufactured by The Nopco Chemical Company 11 grams A-S 1 6C foaming agent also manufactured by The Nopco Chemical Company Another formulation including a polyester selected according to the degree of resilience desired is as follows:

Parts by weight Polyester 100.0 Toluene diisocyanate 35.0 Water 2.4 N-methylmorpholine 1.3 Glycerol monoricinoleate 1.0

The urethane polymers have been found to provide a high degree of adhesion to abrasive grains and the like, permitting dense concentration of such abrasive grains in the working portion of the abrading tool, the amount of polyurethane in the interstices between such grains and serving to bond the same together being further reduced by the inherent foaming reaction (due to presence of water) or by inclusion of a conventional blowing compound which serves to produce a multitude of small cells Within such interstices. The centrifugal action employed in the production of the composite tool also assists in concentrating the abrasive grains in the outer peripheral portion of such tool where they may be effectively utilized.

While the articles with which the present invention is concerned will generally include a yielding resiliently deformable body, which may be of polyurethane rubber for example, such body will ordinarily preferably be of resiliently deformable cellular composition such as foamed polyurethane to afford the desired degree of support and control for the radially extending brush bristles. Where a substantial degree of true brushing action is not required or desired, however, as in the case of certain abrading tools having a high concentration of granular abrasive in the outer peripheral portions thereof, a relatively rigid plastic body comprising, for example, one of the more rigid polyurethane compositions may instead be employed, but such relatively rigid body will also normally desirably he of cellular structure. Tools of these several types are adapted to a variety of different uses including surface finishing, burr removal and the like. They may also be employed in certain quite unrelated fields as, for example, wheels for supporting or propelling various vehicles.

Other modes of applying the principle of the invention may be employed, change being made as regards the details described, provided the features stated in any of the following claims or the equivalent of such be employed.

I therefore particularly point out and distinctly claim as my invention:

1. A brush type rotary tool comprising a rotatable central support and a large number of elongated brushing elements extending substantially directly radially outwardly therefrom with a body of plastic interposed between said elements and maintaining the same substantially uniformly spaced apart to ensure uniform brushing element tip spacing at the Working face of the tool, said plastic body including an integral annular rib on each respective end face of said tool spaced inwardly from the working face of the tool to strengthen the latter.

2. A new rotary brush-like product comprising a central support with bristles secured thereto and extending generally radially outwardly therefrom, said bristles being in rotary dynamically oriented relationship in substantially true radial positions with substantially uniform spacing therebetween, and a body of plastic material between said bristles maintaining said bristles spaced apart in their dynamically oriented positions.

3. The product of claim 2, wherein said bristles comprise fine filaments which are normally somewhat limp.

4. The product of claim 2, wherein said bristle-s are flexible and thus spaced apart and supported by a resiliently deformable cellular plastic composition.

5. The product of claim 2, wherein said bristles are thus spaced apart and supported by a polyurethane plastic.

6. The product of claim 2, wherein said bristles are thus spaced apart and supported by a foamed polyurethane plastic.

References Cited by the Examiner UNITED STATES PATENTS 1,038,682 9/1912 Thompson 2265 2,648,084 8/1953' Swart 15-198 2,680,335 6/1954 Hurst 51504 2,785,442 3/1957 Boggs 264- 311 X 2,862,806 12/1958 Nestor 264 -311 X 2,950,495 8/ 1960 Stingley 15-179 2,972,527 2/1961 Upton 51296 X 2,995,401 8/ 1961 Peterson 300-21 3,076,219 2/1963 Peterson 15-179 FOREIGN PATENTS 1,006,829 4/1957 Germany.

CHARLES A. WI-LLM-UTH, Primary Examiner.

PETER FEDDMAN, Assistant Examiner.

Claims (1)

1. 2. A NEW ROTARY BRUSH-LIKE PRODUCT COMPRISING A CENTRAL SUPPORT WITH BRISTLE SECURED THERETO AND EXTENDING GENERALLY RADIALLY OUTWARDLY THEREFROM, SAID BRISTLES BEING IN ROTARY DYNAMICALLY ORIENTED RELATIONSHIP INSUBSTANTIALLY TRUE RADIAL POSITIONS WITH SUBSTANTIALLY UNIFORM SPACING THEREBETWEEN, AND A BODY OF PLASTIC MATERIAL BETWEEN SAID BRISTLES MAINTAINING SAID BRISTLES SPACED APART IN THEIR DYNAMICALLY ORIENTED POSITIONS.

Images