US 3134122 A
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May 26, 1964 V. K. CHARVAT SELF-REGULATING BRUSHING TOOL Filed May 51, 1961 INVENTOR.
VERNON K. CHARVAT Qberlimmnk OMEHH ATTORNEYS United States Patent 3,134,122 SELF REGULATING BRUSHING TOOL Vernon K. Char-vat, Bay Village, Ohio, assignor to The @sborn Manufacturing Company, Cleveland, Ohio, a corporation of ()hio Fiied May 31, 1951, Ser. No. 113,838 11 Claims. (Cl. 15-179) This invention relates as indicated to a self-regulating brushing tool, and more particularly to a power driven rotary brush, the bristles of which are assembled and treated in a novel manner to enhance the effectiveness of the tool.
By assembling a plurality of generally parallel brush bristles such as wire monofilaments in slightly spaced sideby-side relationship and interconnecting the same by means of a generally continuous layer of flexible plastic, brushing fingers may be produced which when assembled into an annular back, for example, provide a rotary brush having certain very desirable characteristics. In the first place, by thus embedding the bristles in the flexible plastic, it becomes feasible to employ quite hard bristle materials such as steel wire having a Knoop hardness of 700, without danger of excessive long fracture of the bristles and consequent rapid disintegration of the brush in use. Such hard bristle material, of course, is capable of much more rapid cutting action on the work than are bristle materials conventionally employed.
Furthermore, by thus incorporating the bristles in relatively thin, generally flat flexible plastic fingers, such bristles may still be permitted to fiex substantially throughout their length in contrast to certain other brushing tools wherein the bristles may be substantially entirely embedded in a large body of elastomeric material.
It is preferred to employ straight bristle material rather than the commonly employed crimped wire for several reasons including the fact that very hard wire bristles are not capable of being satisfactorily crimped. It is also preferred that the bristles extend substantially radially outward from a central rotatable hub in the case of wheel brushes, for example, and when crimped Wire bristles are employed, the working ends of certain of the bristles will be inclined in the direction of rotation of the tool and will therefore gouge the work, whereas the Working ends of certain of the other bristles will be rearwardly inclined and will simply drag across the work surface.
When very hard brush bristles are embedded in relatively thin flexible plastic fingers, they may nevertheless occasionally break at points substantially spaced from their outer working ends but the plastic material may still suflice to retain the broken portions in the brush. When operating at high speeds of rotation and when a number of the hard bristles break, however, there may be danger of a substantial portion of a brushing finger breaking out of the brush, and it is an object of the present invention so to modify such fingers as to reinforce the same for retention in the brush in the event of long fracture of the hard bristles contained within such fingers.
Another object is to provide modified flexible brushing fingers having straight parallel brush filaments embedded therein, which fingers have modified surface contours assisting in securing such fingers together in a central assembly and also in affording an improved brushing action.
Still another object is to provide a brushing tool wherein the bristles and especially hard monofilaments are mounted in a manner facilitating their controlled flexing in the direction of rotation of the brushing tool while at the same time greatly limiting lateral movement of such filaments.
A further object is to provide an annular rotary brush section having a support portion and brush material extending radially outwardly therefrom so formed and proportioned that when a plurality of such brush sections are assembled in closely packed axial alignment there will be no appreciable regions of reduced bristle density in the resultant cylindrical brush face corresponding to the regions of lateral interface contact of the annular supports.
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 an end view of a power driven rotary brush representing a preferred embodiment of the principles of this invention;
FIG. 2 is an enlarged fragmentary semi-diagrammatic View of a modified brush bristle adapted to be employed in forming the brushing fingers of this invention;
FIG. 3 is a transverse section taken on the line 33 on FIG. 2;
FIG. 4 is a plan view of an array of parallel filaments in accordance with FIG. 2 bonded together by a thin layer of additional plastic to form elongated generally flat flexible strips suitable for employment in the production of brushing fingers, such additional plastic being indicated as transparent better to disclose the beaded filaments bonded thereby;
FIG. 5 is a fragmentary transverse section taken on the line 55 of FIG. 4, on an enlarged scale;
FIG. 6 is a transverse section through the brushing tool of FIG. 1, on an enlarged scale;
FIG. 7 is a further enlarged fragmentary semi-diagrammatic view of a brushing element of this invention showing a portion of the work-engaging end thereof; and
FIG. 8 is a fragmentary cross-section on an enlarged scale taken on the line 8-8 on FIG. 7.
Referring now more particularly to said drawing and especially FIGS. 2-5, thereof, I prefer to utilize beaded wire bristle material of the type disclosed in my prior copending application Serial No. 86,378, filed February 1, 1961, for Brush and Brush Material, now Patent No. 3,090,061 dated May 21, 1963, in preparing the brushing fingers of the present invention. Thus, the hard wire monofilament 1 may have plastic heads 2 adhered thereto at intervals therealong with the intervening portion of the filament coated with a much thinner layer 3 of the plastic, or, if desired, the surface of the monofilament may be exposed intermediate such beads. As explained more in detail in my aforesaid application Serial No. 86,378, a wide variety of brush bristle material may be utilized including steel Wire having a Knoop hardness in excess of 600 and preferably in excess of 700 or even 800, other metal wire such as stainless steel wire, glass monofilaments and the like. A wide variety of plastic materials may be utilized to form the beads 2 and the intervening coatings 3 including nylon, polyurethane, neoprene (polychloroprene), and polyvinyl chloride. Foamed polyurethane and polyurethane rubber have been found especially satisfactory. Such plastic may be further bonded to the bristle 1 by means of various well-known bonding agents such as Ty-PlyS for bonding rubber and rubber-like materials, and epoxy resins for bonding nylon.
Abrasive granules may, if desired, be incorporated in the plastic heads 2, to be released at the brush face as the bristles Wear back in use. Such granular abrasive may, for example, include aluminum oxide (Alundum or Aloxite), silicon carbide (Carborundum, Corun- 3 dum), chrome oxide, natural abrasives (e.g., pumice, emery), and mixtures of these.
:Uniform spacing of the beads 2 along the filament is not necessary, and some irregularity of spacing is, in fact, preferred. In a typical preferred embodiment, the bristles 1 may be .0118 diameter carbon steel wire coated with polyvinyl chloride and provided with beads of the same material, such beads being about 7 in length and occurring at a frequency 'of from about three to about six per linear inch of the bristle length.
A plurality of such beaded bristles may be arranged in parallel array but one bristle in thickness and then bonded together as shown in FIG. 4 by addition of a small amount of plastic which may be of the same type as that already previously employed to form such heads 2 although it will generally be preferred to employ plastic material for this purpose which will separate between the outer working ends of the bristles in use. A continuous elongated substantially fiat plastic band or strip 4 may thus be produced in which the parallel brush filaments :1 are embedded and extend. longitudinally, insuificient additional plastic being employed to submerge the beads 2 which persist as small protuberances or surface rugosities as shown in FIG. 5 in enlarged cross-section. This band or strip 4 may now be cut into desired lengths to form the flexible brushing fingers 5 of this invention.
In the preferred embodiment of the invention illustrated in FIGS. 1 and 6 of the drawing, a large number of such brushing fingers are arranged to form an annulus with such fingers lying in radial planes parallel to the axis of such annulus and with the radial-1y inner ends of such fingers closely packed together in order that a maximum number of fingers may thus be employed. The inner end portions of the fingers are then bonded together with a compatible plastic or cement to form a continuous inner annular support 6. Thus, for example, if the plastic fingers are formed of nylon, such inner annular support may be produced by bonding the closely packed inner end portions of the fingers together with an epoxy resin. As shown, the hard straight wires are thus supported and secured in the finished annular brush section without local bending which would tend to produce concentrations of stress and early fracture when repeatedly rapidly flexed in use.
Now referring more particularly to FIGS. 7 and 8, a generally flat flexible plastic finger 5 is shown comprised of a single row of straight bristle filaments 1 having plastic beads 2 securely adhered thereto, such beaded filaments being joined together by and embedded in plastic material 4 to form thin generally flat flexible fingers 5. Such plastic 4 is sufficiently thin Where it interconnects adjacent filaments (FIG. 8) and/or has relatively low toughness and tensile strength so that it will tend to erode away and separate from between the outer end portions of the bristles in use to expose the latter with their heads 2 still bonded thereon. As best shown in FIG. 8, such thin plastic regions interconnecting adjacent parallel filaments result in the formation of grooves extending longitudinally of the fingers parallel to such filaments, with corresponding ridges where such filaments are embedded. The working ends of the fingers may be initially prepared in this manner, if desired, by subjecting the same to the action of an appropriate power driven rotary brush. Thus, the beads 2 may be of polyurethane firmly bonded to the bristles which may be hard straight wire bristles having a Knoop hardness of at least 700, and the plastic material 4 forming the flexible plastic finger in which the bristles are embedded may be of sponge neoprene (polyohloroprene) which may further contain filling material enhancing the erodability of the sponge neoprene upon engagement with the work under operating conditions. it will be appreciated that the term beads as used herein and in the claims is not intended to be limited to apertured bodies threaded on the bristles but rather includes spaced globules and protuberances adhered to the bristles and which are not necessarily concentric therewith. With flexible brushing fingers of the type shown in FIG. 7, for example, it is possible to achieve very superior brushing characteristics; hard straight bristle wire is suitable for employment, since the disadvantage of long fracture may be largely avoided; the protruding bristle end portions are adapted to operate upon the work in the manner of a true brush in view of the fact that they are capable of individual fiexure in directions circumferential of the tool (FIG. 1); and yet lateral movement of such protruding bristle end portions is very much limited by the beads 2 thereon so that when any bristle end encounters a surface rugosity on the work as the brushing tool rotates thereagainst, it will pass directly over such rugosity with consequent abrading action thereon rather than tending to deviate around such rugosity as has otherwise been the case in the past. This latter feature is of especial importance when brushing to produce a radius on the edge of a metal work-piece, for example. Prior brushing tools having a fast and eificient cutting action have tended to produce something of a saw-tooth effect under such circumstances. It might be said that the brushing tool of this invention as exemplified in FIG. 7 is one having a long trim effect circumferentially of the brush (inasmuch as the brushing fingers are capable of flexing in such direction for substantially their entire length) and a short trim effect laterally of the brush (inasmuch as such fingers are capable of very little flexing in their own plane and the protruding bristle end portions are likewise limited by heads 2 so far as lateral flexing is concerned). It will be appreciated that FIG. 7 of the drawing is semi-diagrammatic in character and that portions of the plastic material 4 may also adhere to the bristle end portions even though the plastic material 4 has separated between such end portions.
As shown in FIG. 5 of the drawing, the bristles 1 em bedded in the flexible plastic fingers may desirably be slightly offset one from another in a generally zigzag manner rather than forming a perfectly straight alignment. Such relative oifsetting of the brush bristle filaments (in a direction circumferentially of the tool as shown in the FIG. 1 embodiment) may ordinarily be in an amount approximately equal to the diameter of such filaments and even a little more, up to about .01 inch in the case of the typical preferred embodiment in which the bristles are .0118 inch diameter carbon steel wire. Even a very small offset such as .005 inch is appreciably advantageous in effecting improved operating results, the faces of the finger having a corresponding zigzag conformation in cross-section as indicated in FIG. 5. More particularly, such arrangement of the bristles assists in snubbing flexure of the fingers in a circumferential direction when the PEG. 1 embodiment of the invention is rotated at high speed in engagement with the work, and the working ends of the individual bristles are prevented from skipping and bouncing upon impact against the work surface. Consequently, a controlled brushing action is obtained wherein each bristle tip is caused to travel in a substantially straight line across the work surface to produce a finish more nearly similar to that obtained with other types of abrading tools such as conventional abrasive belts, for example. This type of action is much preferred in certain commercial abrading operations such as the removal of solder from automobile bodies and the like. The brushing tool of this invention accordingly has a high degree of lateral stability and yet the brush material is enabled to flex in a circumferential direction with such latter flexibility, however, diminishing in increments toward the central support.
In view of the foregoing, it is now possible to provide high speed rotary brushing tools utilizing hard and therefore very effective bristle materials without decreased brush life due to long fracture thereof and without production of a non-uniform and inferior surface finish which would normally be anticipated when employing such materials. Certain subject matter disclosed but not claimed herein is disclosed and claimed in my co-pending application Serial No. 347,881 entitled Self-Regulating Composite Brushing Tool, filed February 27, 1964.
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 brushing tool comprising a support, thin flexible plastic fingers secured thereto and extending therefrom, and a single row of parallel brush bristle filaments embedded in said fingers extending longitudinally thereof, said plastic fingers having a multitude of small local plastic protuberances on their faces, said protuberances being spaced from each other both laterally and longitudinally of said fingers, and said protuberances being thereby adapted to space adjacent fingers somewhat apart and regulate interaction of said fingers.
2. The tool of claim 1, wherein said brush material comprises a single row of parallel brush bristle filaments extending longitudinally of said fingers, and the surfaces of said fingers have longitudinally extending grooves between and parallel to said filaments with said protuberances projecting from the corresponding ridges intermediate such grooves.
3. A rotary brushing tool comprising a rotatable support and brushing elements secured thereto and extending generally radially outwardly therefrom, said elements comprising thin generally flat flexible fingers disposed in planes parallel to the axis of rotation of said tool and closely compacted in the region of said support, hard wire bristles embedded in said fingers longitudinally thereof with said wire bristles in any one finger extending parallel to one another in a single row, and a multitude of small local plastic protuberances on the faces of said fingers, said protuberances being spaced from each other both laterally and longitudinally of said fingers, and said protuberances being thereby adapted to regulate interaction of the latter.
4. A rotary brushing tool comprising a rotatable annular plastic support of rectangular cross-section and brushing elements embedded in said support and extending radially outwardly therefrom, said elements comprising thin, flexible, generally fiat rectangular plastic fingers formed of plastic beaded metal wires bonded together by plastic and extending parallel to one another longitudinally of said fingers and radially outwardly from said support, the diameter of said annular support being substantially greater than the length of said fingers protruding therefrom, and the width of said fingers being the same as the width of said support, said plastic fingers having a multitude of small local plastic protuberances on their faces spaced from each other both laterally and longitudinally of said fingers.
5. A brushing tool comprising a support, thin generally flat flexible plastic fingers secured thereto and extending therefrom, a single row of brush bristles embedded in each of said fingers and extending longitudinally thereof, and a multitude of small longitudinally spaced protuberances on said individual bristles, the plastic being sulficiently thin that the outer end portions of said bristles are adapted to separate one from another by progressive separation of the plastic of said fingers therebetween upon operative engagement with the work and said protuberances appear on the faces of said fingers.
6. A rotary brushing tool comprising a rotatable support portion and a plurality of generally flat thin flexible plastic fingers extending therefrom, said fingers having a single row of parallel bristle elements embedded therein, and said bristle elements having small beads secured thereto at closely spaced intervals therealong, the plastic material of said fingers being adapted to separate between the outer end portions of said bristle elements in use to cause said end portions to extend therefrom with the individual movements of said end portions regulated and limited by said beads thereon, said beads producing corresponding protuberances on the faces of said fingers.
-7. A rotary brushing tool comprising a rotatable support portion and a plurality of closely packed generally flat thin flexible polyurethane plastic fingers extending therefrom in radial planes relative to the axis of rotation of said support portion, said fingers each having a single zigzag row of straight parallel slightly spaced wire bristles embedded therein and extending longitudinally thereof, said bristles having a Knoop hardness of at least 700, and small plastic beads securely adhered to said bristles at closely spaced intervals therealong, said beaded bristles protruding a short distance from the outer working ends of said fingers.
8. A brushing tool having a number of adjacent thin generally fiat flexible plastic fingers, each said finger having a single zigzag row of parallel brush bristle filaments embedded therein and extending longitudinally thereof, the faces of said finger having a corresponding zigzag conformation in cross-section.
9. The tool of claim 8, wherein said individual filaments have a multitude of small protuberances thereon.
10. A rotary brushing tool comprising an assemblage of thin generally fiat flexible plastic fingers, each said finger having a single zigzag row of brush bristle filaments embedded therein and extending longitudinally thereof, with the faces of said finger having a corresponding zigzag conformation in cross-section, said fingers lying in radial planes relative to the axis of rotation of said tool, and a multitude of small protuberances on said individual filaments, said bristle filaments with said protuberances thereon protruding a short distance from the outer working ends of said fingers.
11. A rotary brushing tool comprising a rotatable support portion and a plurality of generally fiat thin flexible plastic fingers closely packed around the entire circumference of said support portion and extending therefrom in radial planes relative to the axis of rotation of said support portion, said fingers each having a plurality of parallel longitudinally extending bristles embedded therein, and a large number of small random plastic protuberances on the opposed generally flat faces of said fingers spaced both longitudinally and laterally of said fingers to regulate the interaction of said fingers.
References Cited in the file of this patent UNITED STATES PATENTS 205,374 Foss June 25, 1878 2,171,805 Picard Sept. 5, 1953 2,642,705 Jensen June 23, 1953 2,807,825 Gardner Oct. 1, 1957 2,818,691 Leggett Jan. 7, 1958 2,917,779 Kurzke Dec. 22, 1959 2,984,053 Peterson May 16, 1961
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