US2789302A - Balanced rotary brush - Google Patents

Description

April 23, 1957 A. T. scHoFlELD 2,789,302

BALANCED ROTARY BRUSH Filed June 29, 1954 2 Sheets-Sme# 1 Hlm" R INVENTOR. ART/Me scanf/Lp MMM April 23, 1957 A. T. scHoFlELD L BALANCED ROTARY BRUSH Filed June 29, 1954 2 Sheets-Sheet 2 A INVENTOR. ARTHUR 7: SCHOf/ELD A TTo/Q/veys Osborn Manufacturing Company, Ceveiand, Ohio, a corporation -of Ohio Application June 29, 1954, Serial No. 440,083

14 Claims. k(Cl. 15-17i-9) This invention relates as indicated to a rotary brush, and more particularly to an annular ,rotary brush having a back member and a retaining member operative to secure and retain the brush material 'in such back.

While not 'limited thereto, my invention is particularly suitable and advantageous when employed in conjunction with the form of brush construction disclosed and claimed in Whittle Patent 2,288,337. It may also be utilized, however, in other forms of brush construction having annular channelform backs and retaining elements such as wire loops and sheet metal washers for holding the brush material in place.

Of recent years there has been Yan increasing tendency to utilize power driven rotary brushes vgenerally as precision tools for the ,performance of many very delicate brushing operations, and 'it has vconsequently become ymore and more important that 'the density of brush material ll he uniform, that the brush trim be uniform and to precise specications, and that the brush .be very accurately balanced especially for high speed operation. Despite improvements 'in the measuring .of the brush bristle material and finishing of the brush surfaces, .it has been found that under conditions of :use and particularly when operated at high speeds for considerable periods of time, annular rotary brushes tend to become .out of balance, if this is not already the case. This militates against their efficient use .in many types of applications. After 'much investigation, it was determined Vthat the principal -cause .of this ditculty ,is the shifting vof the retainhig element eccentricallytof the brush .axisand brush back. Such shifting not only serves to throw the brush oit balance but also .permits loosening of 4a portion ofthe brush material with consequent shifting of such material circumferentia'lly and also, `in .some cases, shedding. This situation is particularly likely to .be prevalent when employing brush bristle material such as crimped wire, bundles of .the latter frequently :being very dissimilar in their compressibility `even when ,of Valmost exactly the same weight. In the Whittle .type of brush construction above referred to, if several .of the more compressible bundles of Vbrush material 4are distributed ontone side of the brush back, Vthe retaining :member will shift eccentrically while being shrunk down upon :the .brush material in accordance with the Whittle teaching.

It is accordingly a l,plincipal object ofgmy invention to provide a rotary brush wherein the brush -bristle material is retained ,in place by .a retaining element positively located .and spaced to prevent-development-of eccentrici'ty and imbalance.

Another -object is to provide ysuch brush .in .the form of an annular section such tas that taught in Whittle Pa-tent 2,288,337.

Still Ianother object is to provide means in Aconjunction with such retaining element positioning means :adapted to assist in seating the brush element :upon an appropriate hub -or adapter.

A further object is to provide such brush in lwhich `2 the `brush material is rmly held against shedding and also against shifting circumferentially of the brush.

Other objects of the invention will appear as the description proceeds.

VTo 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.

ln said annexed drawing:

Fig. l is an end View of a rotary brush of the vgeneral type taught in A'Whittle 'Patent 2,288,337 modified in accordance with my invention;

Fig. 2 is a transverse radial section taken on the line 2-2 on Fig. l;

Figs. 3 and 4 are two fragmentary transverse sections illustrating stages in the manufacture of my new brush;

Fig. '5 is a fragmentary section circumferentially of the brush back taken on the line 5 5 on Fig. l;

Figs. 6 and 7 are enlarged Vtransverse sections generally similar to Fig. 2 but showing ,steps in the production of a somewhat modified ,form Vofbrush assembly utilizing a sheet metal Washer as the brush material retaining elcment;

Fig. 8 resembles Fig. 7 but with a wire retaining element;

Fig. 9 is a fragmentary view of .an annular brush element as shown in Fig. l mounted von ,a special hub or adapter;

Fig. l0 is a transverse Asection .taken on Vthe line ill-dii on Fig. 9; and

Fig. ll is a 'fragmentary View of a backing strip having special yteeth or supporting elements welded thereto.

Now referring `more particularly `to said annexed drawing, the embodiment illustrated -in Figs. Vl, 2 and 5 comprises a sheet metal channelform annulus the sides 2 and 3 of which extend radially outwardly. Such annulus may desirably be formed by circularizing a strip of sheet metal and joining vthe opposed ends by means of a weld 4, such weld being of substantially .the same thickness as the remainder of Vthe strip .so vas vnot to afford Va source of unbalance. Brush material such as bristles 5 are doubled about `an annular retaining .element -6 -within `the brush back channel with the slightly Yflaring brush material extending generally radially from the latter. y[he back i' and retaining element t6 are preferably :assembled in the general manner taught in Whittle Patent 2,288,337, modified however Vby the tact that transverse teeth or projections 7 4are Astruck up at intervals from the center portion of the backing strip 1, such teeth extending radially outwardly `and leaving corresponding holes or apertures 8 in the inner peripheij, of the circularized strip. The crowns of such teeth will preferably 'be somewhat concave or notched las shown in order Vto assist in centering the retaining element L6.

In Vassembling the brush, the annulus 1 `with the `series of radially projecting .teeth '7 is :somewhat dared Yat one end 9 and a somewhat narrower sheet metal Aanmrlus 6 of outwardly concave cross-section is `centered over such teeth-as show-nin Fig. The measured bundles of `brush bristle material are next inserted between the -two annali, such teeth serving to .assist in .maintaining accurate uniform circumferential distribution of Athe bristle material. The other `edge 10 of strip 1 is now also dared .as Vshown in `Fig. 4 and a sufficiently stable assemblt is thereby .produced to permit handling and placing upon an appropriate press whereby such flared edge portions 9 and lll are forced toward each lother to "orm the' annular channel- 'form brush back of general -U-shap'ed cross-section as 3 shown in Fig. 2. Such forming operation serves also laterally to compress the concave retaining element 6 to collapse the same as shown in Fig. 2. As explained in Whittle Patent 2,288,337, such lateral compression of.-1`etaining element 6 is effective to produce radially inward shrinking of such annulus irmly to compress and secure the brush bristles 5 within the channel back 1. The density of brush bristle ll and the height of the projections 7 are selected so that upon such vshrinking of annular retaining elernent 6 Vthe latter is exceedingly firmly seated against such projections and the brush bristle material is very densely and firmly compacted intermediate element 6 and channel back 1. It will, of course, at once be apparent that projections 7 serve to prevent any shifting of annulus 6 eccentrically of back 1, and this major cause of brush unbalance is accordingly eliminated.

As also taught in Whittle Patent 2,288,3 37, the sides 2 and 3 of the annular back may be locally compressed to form radial grooves 11 extending from the outer edges of the channel sides to the inner periphery of the back and thereby affording Ventilating passages when a plurality of the annular sections are assembled side by side upon appropriate hubs or adapters.

Now referring to Figs. 6 and 7 of the drawing, a soniewhat modified form of assembly is illustrated. The teeth 7 are notched as at 12 to receive and center a fiat sheet metal washer 13, the inner diameter of which is sufficiently large to clear the crowns of the radially extending projections 7 during initial assembly (Fig. 6). The annular channelform back 1 is then expanded over an appropriate forming die to seat washer 13 rmly in notches 12 (Fig. 7), thereby finally compacting the brush bristle material 5 between such retaining element 13 and the back 1 and Valso permanently centering retaining element 13 both radially and laterally of the assembly.

In the Fig. 8 embodiment of my invention, I utilize a wire retaining element 14 which may be seated in notches 15 of teeth or projections 7 in the same manner as washer 13 or which may alternatively be thus seated simply by tensioning the wire and then securing the ends of the same together as by welding or twisting. In other words, this type of retaining element may either be shrunk down upon the projection 7 or the channel back 1 may be expanded toV engage the same. When the'wire retaining element 14 is employed, it may be desirable somewhat to compress the radially outward opening of back 1 to atford a constricted pressure neck.

As shown in Fig. l1, teeth or projections 18 generally equivalent to projections 7 may be formed in various ways other than by punching them up from the inner periphery of annulus 1. Thus, as shown in Fig. 11, such teeth may be spot welded as at 19 to such annulus.

When the teeth or projections 7 are punched up from strip 1 as described above, leaving equally circumferentially spaced openings 8 in the inner periphery of the annular channelform back 1, such openings may be utilized to assist in the seating of the annular brush section on an appropriate hub or adapted as illustrated in Figs. 9 and 10, for example. In the form illustrated, such adapter comprises an annular portion 20 adapted to lit on an appropriate arbor or mandrel and having spokes 21 extending radially therefrom. Such spokes have arcuate end portions 22 adapted to bear against and support the inner periphery of channel back 1 and are also provided with radially outwardly protruding buttons 23 adapted to be pressed into the openings 8 and thereby to assist in securing the annular brush section against rotation relative to the adapter on which it is mounted. Such adapters may be of cardboard, vulcanized ber, synthetic plastic, and other suitable materials. When formed as shown, they may be snapped in place with relatively little effort and yet atord means for proper driving of the brush as well as seating and centering the same. An adapter having a roughened outer periphery adapted to seat the annular brush section may similarly be employed, such roughened periphery drivingly engaging the openings 8.

Any of the well-known brush bristle materials may be utilized such as, for example, horsehair, tampico fiber, crimped wire, nylon, plastic coated wire, and plastic coated glass iiber strands. The channel back and retaining element will usually be of sheet metal such as steel but other appropriate materials may obviously be employed depending on the use intended.

When forming the teeth or projections 7, it is desirable to use a double die to score the bristle side of the annulus 1 before punching up the teeth, thereby to avoid sharp edges on the teeth and the holes 8 which might otherwise eventually tend to cut some of the adjacent brush bristles. By rounding the corners of such teeth or projections, the development of undesirable stress concentrations is also avoided.

It will be apparent that not only have I provided a balanced rotary brush suitable for high speed operation, but also such brush construction serves to prevent circumferential shifting of the brush bristle material. Accordingly, brushes of this type may be produced to very precise and accurate specifications and will maintain the desired characteristics through long periods of use.

When inserting the brush bristle material it is desirable to select bundles of bristles of a size to permit achieving the required density by insertion of an evenV number of bundles between adjacent projections 7. This much facilitates the obtaining of uniform circumferential bristle distribution and even balance.

Other modes of yapplying 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.

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

l. ln an annular rotary brush section comprising an annular sheet metal continuous channel back opening radially outwardly, an annular retaining element within said channel, and brush material secured beneath said retaining element in said channel and extending generally radially therefrom in a substantially uninterrupted layer; a plurality of thin transverse radial projections on said back within said channel substantially uniformly distributed about the circumference thereof penetrating said brush material and engaging the inner periphery of said retaining yelement to maintain the latter con-centric with said back.

2. in an annular rotary brush section comprising an annular sheet metal channel back opening radially outwardly, an annular retaining element Within said channel, and brush material secured beneath said retaining element in said channel and extending vgenerally radially therefrom; a plurality of thin transverse radial projections on said back Within said channel substantially uniformly distributed about the circumference thereof, said projections having concave radially outer transverse edge portions with the inner periphery of said retaining element firmly seated Ithereon to maintain said retaining element concentric with said back.

3. In an annular rotary brush section comprising an annular sheet metal channel back opening radially outwardly, an annular retaining element within said channel, and brush material secured beneath said retaining element in said channel 'and extending generally radially therefrom; a plurality of thin transverse radial projections on said back within said channel substantially uniformly distributed about the circumference thereof, said projections wardly, an annular retaining element within said channel, and brush material secured beneath said retaining element in said channel and extending generally radially therefrom; a plurality of thin transverse radial projections on said back within said channel substantially uniformly distributed about the circumference thereof, said projections having notched radially outer transverse edge portions With the inner periphery of said retaining element firmly seated thereon to maintain said retaining element concentric with said back, said retaining element comprising la flat sheet metal ring engaged in such notches.

5. In an annular rotary brush section comprising an annular sheet metal channel back opening radially ontwardly, an annular retaining element within said channel, and brush material secured beneath said retaining element in said channel and extending generally radially therefrom; a plurality of thin transverse radial projections on said back Within said channel substantially uniformly distributed about the circumference thereof, said projections having notched radially outer transverse edge portions with the inner periphery of said retaining ele- -ment rmly seated thereon to maintain said retaining element concentric with said back, said retaining element comprising a Wire ring engaged in such notches.

6. In an annular rotary brush section comprising an annular sheet metal channel back opening radially outwardly, an annular retaining element within said channel, and brush material secured beneath said retaining element in said channel and extending generally radially therefrom; a plurality of thin transverse radial projections on said back within said channel substantially uniformly distributed about the circumference thereof, said projections having concave radially outer transverse edge portions with the inner periphery of said retaining element firmly seated thereon to maintain said retaining element concentric with said back, said retaining element comprising a sheet metal ring of collapsed U-shaped cross-section, the base of such U projecting inwardly and engaging such concave edges of said projections.

7. In an annular rotary brush section comprising an annular sheet metal channel back opening radially outwardly, fan annular retaining element within said channel, and brush material secured beneath said retaining element in said 4channel and extending generally radially therefrom; a plurality of thin transverse projections punched up from the inner periphery of said back and extending radially within said channel, said projections being substantially uniformly distributed about such back `and Ermly engaging the inner periphery of said retaining element to maintain the latter concentric with said back.

8. In an annular rotary brush section comprising an annular sheet metal channel back opening radially outwardly', an annular retaining element within said channel, and brush material secured beneath said retaining element in said channel and extending generally radially therefrom; a plurality of thin transverse projections punched up from the inner periphery of said back and extending radially within said channel, said projections being substantially uniformly distributed labout such back and firmly engaging the inner periphery of said retaining element to maintain the latter concentric with said back, and an annular adapter seating such inner periphery of said back having protuberances lengaged in the openings left in said back by said punched-up projections.

9. In an annular rotary brush section comprising an annular sheet metal channel back opening radially outwardiy, an annular retaining element Within said channel, and brush material secured beneath said retaining element in said channel and extending generally radially therefrom; a plurality of thin transverse projections punched up from the inner periphery of said back and extending radially within said channel, said projections being substantially uniformly distributed about such back and firmly engaging the inner periphery of said retaining element to maintain the latter concentric With said back, and a rotatable hub having an outer periphery seating such inner periphery of said back and engaging in the openings left in said back by said punched-up projections.

10. The method of forming an annular rotary brush section which comprises forming a cylindrical sheet metal ring, punching up a plurality of radially outwardly protruding thin transverse teeth on such ring, said teeth being uniformly distributed circumferentially of such ring, placing uniform quantities of brush material intermediate such teeth generally parallel to the axis of such ring, fitting a second cylindrical sheet metal ring over such teeth and brush material -co-axially with such first ring, forming both such rings to radially outward U-shaped :cross-section to retain su-ch brush material within such first ring by such second ring, and `collapsing the sides of such second U-shaped ring to shrink such ring down on such teeth in rigid concentricity with such first ring, such teeth penetrating such brush material.

11. The method of forming an annular rotary brush section which comprises forming a ycylindrical sheet metal ring, forming a plurality of radially outwardly protruding thin transverse teeth on such ring distributed circumferentially thereof, placing brush material intermediate such teeth generally parallel to the axis of such ring, tting a second cylindrical sheet metal ring of shallow U-shape cross-section over such teeth and brush material co-axially with such first ring, forming such first ring to radially outward U-shape cross-section with such second ring retaining such brush material therewithin, and ycompressing the sides of such second ring toward each other to shrink such ring down on such teeth in rigid concentricity with such first ring, such teeth penetrating such brush material.

12. The method of forming a rotary brush which comprises interposing compressible brush material between a central circular support and an outer ring, providing circumferentially distributed thin rigid spacing elements between such support and ring, and shrinking such ring down on such elements in rigid concentricity with such central support, such thin rigid elements penetrating such brush material.

13. The method of forming a rotary brush which cornprises interposing compressible brush material between a central circular support and an outer ring, providing circumferentially distributed thin rigid spacing elements between such support and ring, and expanding such support rigidly to engage such elements with the inner periphery of such ring to hold the latter concentric with such support, such thin rigid elements penetrating such brush material.

14. In an annular rotary brush section comprising an annular sheet metal channel back opening radially outwardly, an annular retaining element within said channel, and brush material secured beneath said retaining element in said channel and extending generally radially therefrom; a plurality of thin transverse projections punched up from the inner periphery of said back and each extending radially within said channel an equal distance outwardly therefrom toward said retaining element, said projection being substantially uniformly distributed about said back accurately to tix by their outermost edges the radially innermost distance to which said retaining element may contract during the assembly of said brush.

References Cited in the file of this patent UNITED STATES PATENTS 1,800,376 Cornell Apr. 14, 1931 2,288,337 Whittle June 30, 1942 2,409,309 Peterson Oct. 15, 1946 2,616,111 Vose Nov. 4, 1952

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