US2286972A - Renovating of paint brushes - Google Patents

Description

June 16, 1942. w. E. NASH, JR

RENovATING oF PAINT BRUSHES Filed Nov. 1o, 1959 Nash/J.o i

Patented June 16', 1942 UNITEDA STATES "PA'iEN'ry oFFlcE 2,286,972 RNOVATING F PAINT BRUSHES Will E. Nash, Jr., Lincoln, Nebr.

Application November 10, 1939, Serial No. 303,850

Claims.

- tion of a particular paint or painted surface is concerned, by particles of oil or a previously used y paint remaining in the brush, the importance of proper brush-cleaning is, of course, obvious. It is also Well `known that the finish obtained in a particular painted surface varies with the effective length of the bristles of the paint brush, and where inefficient cleaning of the brush has allower paint to harden in the base of' the bristles of the brush, the effective length of the bristles is reduced so that it often produc/es an undesirable effect on the paint finish.

In prior practice it has been customary for the painter, after soaking a brush in a solvent, such as turpentine,to endeavor to work the paint and the solvent out of the bristles by rubbing the brush back and forth over a waste board or other surface in amanner generally similar to a painting stroke, but with a greater flexure of the bristles; or by beating the brush over an edge of some solid structure such as a fence or post. Such manipulation of the brush tends to loosen and remove the accumulated paint particles and the excess solvent from the base of the brush, but the operation is a tedious, laborious and timeconsuming one which at its best does not remove all of the oil, dissolved paint or encrusted paint from the brush base." Furthermore, the use of the beating method causes breaking of the bristles. and often results in breakage of the metal ferrule whichholds the brush tuft in place on the handle. One of the major .difficulties experienced with a brush thus treated arises in subsequent use of the brush in overhead painting.

of paint, so that there is danger .of producing undesired variation in the finished surface. 'I'his In such overhead use the solvent vor oil remainv ing in the brush base tends to run down the brush handle onto the painters arms and hands, carrying with it the paint which has been dissolved therein. This causes great inconvenience to the painter and necessitatesl frequent descent from the ladder or scaffold for the purpose of removing the paint from the painters arms, hands and clothes. Such retained solvent in the brush trouble is quite serious where a brush which has been kept in linseed oil overnight is used to apply fiat wall paint. In such use the oil, which cannot be completely removed by prior methods, causes glossy spots to be formed on the otherwise dull or fiat coated surface. l

With respect: to the paint which `cannot be removed by prior cleaning methods, it is well known that there is a gradual hardening and stiffening within the base of the brush and that a crust of thick paint is formed about and within the base of the brush. This crust of paint becomes relatively hard in the outer layers of thel bristles adjacent to the base of the brush and it is common practice for painters, in an endeavor to remove the stiffness thus imparted to the brush, to cut off the stiffened outer layer of bristles, thereby reducing the thickness and width oi.' the brush and resulting in an early discard of the brush. This hardened paint within the base or heel of the brush also reduces the, effective length of the bristles so as to have an adverse effect upon the quality of the painted surface.

Since good quality long bristle brushes are relatively expensive, this gradual cutting away of the bristles and the gradual and sometimes uneven reduction in the effective length of the bristles is objectionable and costly.

The aforementioned prior methods of cleaning brushes are such as to require considerable expenditure of time, for example, ten to twenty minutes per brush, and the results of such cleaning are quite unsatisfactory, as above pointed out.

' An important object, therefore, of the present vent used for rinsing is saved for use as a soakingA solution for other brushes.

Another object is r,to enable paint brushes to be thoroughly cleaned by simple and easily performed operation in which the slight exertion required upon`the part of the painter differs radically from the exertion required in normal painting operation, thereby to avoid fatigue which might tend to reduce the painters efficiency in base also tends to thin out the first few brushfuls 55/ his normal painting work.

A further object is to enable the painter to clean his brushes rapidly and effectively within the building in which he is performing his work.

Another object is to enable a painter to change from one color, or type of paint, or surface coating to another without the necessity ofl having a different brush for each type or color which he intends to use, thereby reducing the investment heretofore required in brushes.

Other objects and advantages will become apparent from the following description, taken in connection with the accompanying drawing, in which:

Fig. 1 is an elevational view showing a paint brush cleaning and renovating device embodyingV the invention, the view being such as to show the device in a sectionally illustrated container in the position employed in the practice of my novel method.

Fig. 2 is a sectional view showing the brush holder of the device of Fig. 1.

Fig. 3 is a sectional view takenthrough the device on the line 3-3 of Fig. 2.

Fig. 4 is a fragmental sectional view taken along the line 4-4 of Fig. 2.

Figs. 5 and 6 are side views of different types of brushes which may be renovated in accordance .with the present invention. f

Fig. 7 is a bottom view of the brush shown in Fig. 1 showing the bristles in similar extended positions. Y

'I'his application is a continuation in part of my co-pending application, Serial No. 263,937

led March 24, 1939, and abandoned Feb. 28,

1940. In accordance with the present invention paint brushes such as the large brush 33 of Fig. 5 or the relatively small brush 3l of Fig. 6, or brushes of intermediate or smaller sizes, may becleaned thoroughly and quickly even though long periods of improper cleaning have' produced a crust of hardened paint' therein. -Brushes such as the brushes 33 and 3i have their bristles 32 secured to and projecting in parallel relation to each other from a wideflat brush head 33, there being a metallic ferrule 34a surrounding a part of the head 33 and base portion of the bristles 32. The bristles are secured within the ferrule 34 by various methods, such as by vulcanizing the base of the brush tuft into a hard rubber body I brush handle, and at a rapid rate such that the or block, which block is interlocked or nailed to the ferrule; From the opposite side of the head 33 an elongated handle 34 projects parallel to the normal positioning of the bristles 32 and substantially centered with relation to the side and end surfaces of the head 33. The handle 34 is conventionally formed to provide a grip p0rtion 35, adapted to be conveniently grasped by the worker, and in the form shown in Fig'. 6 this grip portion tapers outwardly or toward a large diameter as at 33 from a narrow neck portion 31 vadjacent -the head 33 to an `enlarged cen-` tral portion and then inwardly toward the end 33 remote from the head 33. The end 33 may be rounded as shown in Fig. 1 or may take a 65 more pointed form of Fig. 6, or in some cases may be relatively broad and flat. In such conventional brushes the shape and length of the handles may vary .to some extent but in most cases such variation is slight, and the tapered r book and forth with the reversal of the painting stroke causes an accumulation of paint 'to occur in the base' of the bristles. This accumulation is generally confined to that portion or zone (generally triangular in cross section) of the base of the bristles defined by the dotted lines 43 in Fig. 2, this portion of the bristles being subject to the least amount of fiexure in the painting operation. Moreover, when the usual cleaning methods or operations are used upon such a brush, this same lack of appreciable flexure in the zone 43 permits this accumulation of paint to remain in a large measure within the brush. If this encrusted paint in the .zone 43 is allowed to harden, there is, of course, a corresponding reduction in the possible flexure of the base portion of the bristles with the result that in subsequent painting operations the zone 43 tends to4 enlarge in the same manner and for the same reasons as caused its original formation.`

In accordance with the present invention paint brushes are cleaned through a series of soaking and rinsing operations in connection with which I apply centrifugal force to the bristles of the brush, and to the paint and solvent in the brush, in such a manner as to loosen and break up the hardened or stiff paint and discharge such paint and solvent from the bristles thereof; and in attaining this result, the brush is preferably so mounted and is rotated at such a spoed that fiexure of the bristles under the influence of cenftrifugal force induces a breaking up of the paint in zone 43 and facilitates the discharge of, dissolved paint as well as encrusted paint particles from the brush. 'I'his desired ilexure .of the bristles is preferably such as tobe, in a measure. the reverse of the nexure which takes place during the building up of the encrusted ox' hardened paint zone 43 in the base, thereby to cause such ilexure of the bristles in my improved cleaning method to break up or tend to break up the encrusted paint in'zone 43 and thereby facilitate its removal or discharge from the brush.

Thus, in the practice of my .improved method of cleaning paint brushes, in its preferred mode, I soak the brush in a suitable solvent such as turpentine until the paint in the brush has been softened and dissolved at least in part; and thereafter the brush is rotated within a protective enclosure substantially about the axis of the increases, the bristles most remote from the rotative axis will rst be bent or flexed, and that the flexure of the bristles `will progress toward the axis as the speed increases. Thus the first flexed bristles will tend to separate from the still unfiexed or less flexed bristles which are closer to the rotative axis, thereby to separate or tend to separate `from the main body of encrusted paint any paint whichis attached to such first flexed bristles. As a consequence there is "a pro= gressive separating or breaking up of the encrusted paint, and during such progressive action the discharge o f the paint particles, or solvent carried by or attached to the progressively vflexed bristles is facilitated by the separation of q central bristles Varies with the effective length of the bristles, theV speed required to properly flex a long bristle brush being considerably less than the ultimate speed required withashort bristle brush. As the speed of rotation of a brush is increased, it will be observed that there will be a hollow cone-sh-aped void formed centrally of the brush tuft, indicating fiexure of all of the bristlesJ away from the rotative axis. Thus, when the paint within the brush has been sufiiciently softened, a large part of such paint will be dis- /charged from the bristles by rotation at a speed suiiicient to produce such a conical void in the brush tuft. At this speed, however, a considerable period of rotation is required; and the separating or breaking force applied to the central portion of any encrusted paint in the zonel 40 is practically negligible, so that the desired breaking up of the paint in zone 40 will not ,be attained; and since it is desirable to reduce the time required both as to soaking and as to the rotative operation, and since the destruction of the stiflening paint mass in zone Il! is desired, I prefer to employ speeds considerably in excess of the speed defined by the initial formation of a conical void in the brush tuft, or defined by flexure of all the bristles Where other axes of rotation are employed. By the use of such higher speed of rotation, the outwardly flexed bristles are caused to exert a substantial lateral pull on vany encrusted paint in the zone 40, thereby causing quick and effective destruction and removal of this objectionable brush-stiiening mass. Moreover, the added centrifugal force causes quicker and more complete discharge of the paint and solvent from the brush. `In practice it has been found that where a properly soaked brush of a ve inch bristle length is rotated about the axis of its handle from zero speed up to 780 revolutions per minute, substantially all of the solvent and most of the encrusted or hardened paint from the zoneMl will be discharged during ing operation. If an ultimate speed of less than 780 revolutions per minute is employed with a brush of this bristle length, the time allowed for each operation, including the preliminary soaking of the brush, must be considerably lengthened in order to attain the desired degree of paint removal. Similarly, an increase in the ultimate speed of rotation of the brush about its handle axis makes it possible to reduce the/operating periods to a slight extent, but I prefer to avoid undue speed because of the accompanying necessity for increased accuracy of mounting and balancing of the brush with relation to the rotative axis.

, tion, 'say 5 to 15 seconds, as in the initial clean- The minimum speed required for various brush or bristle lengths varies in substantially predeit is possible that in some cases the portion of the bristles within the stiifened zone 4l may be so firmly held in place as to introduce a slight variation in the required minimum speed. This variation is most noticeable, of course, in brushes having relatively short bristles, such for example as a lbrush having bristles two inches long, where a half inch of stifened bristle in the zone ll will reduce the eiective or initially ,bendabie length of the bristles to one and one-half inches. Theoretically this relatively large reduction in the initially bendable length of the bristles would require arconsiderable increase in the minimum speed, but in practice, this is not necessary since those brushes which are in a badly caked or still.'- ened condition may be soaked for longer periods and in more active solvents than are usually used.

The caked or stiffened portion is thereby removed in the'rotation of the brush as above described, and after the brush has thus been restored to a substantially normal degree of ilexibility, substantially the full bristle length will become effective in the cleaning operation.

From various tests to determine the minimum operating speed for several bristle lengths, an approximate algebraic formula for the minimum effective speed may be derived from the fundamental formula for centrifugal force. In deriving this `formula I have taken the minimum effective speed to be that speed which attains the desired flexure of the most central ones of the bristles of a brush. The formula for centrifugal force is: W (A) CF equals '(21rN)2.r

Upon the assumption that )the same centrifugal force or outward-pull on the central bristles is required for any bristle length, we may equate a known and satisfactory set of conditions in the above-formula against a second set of conditions where all factors are known except the required minimum speed. In setting up such an equation, the varying stiffness of various types oi' bristles is disregarded, and the weight of the bristles per unit of length is taken as uniform and equal Iin the two brushes under consideration; and the term W is therefore replacedby the term KI, representing the bristle length in units, such as inches, multiplied by a constant K representing the weight per unit of length. Thus we have the following equation: K'L,(2N,)2

as a constant C multiplied by the bristle length,

the formula becomes:

and cancelling,

(LNNOZ equals (L2)2(N2) (E) I N2 equals 2 By use of the foregoing formula, a speed known to be satisfactory for a particular bristle length may be used to derive a constant, which, when substituted for the quantity LiNi will define the approximate minimum speed in terms of bristle length.

termined relation to such bristle length, although Thus, it has been found that a speed of 1300 of the output shaft 54.

R. P. M. is satisfactory for a bristle length of 2% inches, and substituting these values, we have (F) N equals :Big5

- the efficiency of paint removal falls off very rapidly as the constant varies from about 3300 down to 3000. 'I'hus it is `desirable to maintain this constant above 3300.

It has also been found that as the speed for a particular bristle length is increased so that this constant increases above 3700, very little added eihciency of paint removal is attained; while the danger due to high speed rotation with a slight eccentricity in the mounted brush is materially increased. `This danger is relatively slight so long as the speed for each particular bristle length is maintained at such 'a figure that the constant in the above formula is relatively close to 3500.

Therefore, I prefer to maintain the constant at between 3300 and 4000; although there may be some variation from these figures. Thus the preferred speed for brushes of different bristle lengths may be defined as (G) N equals By maintaining the speed relatively close to the minimum for each particular bristle length, danger due to improper centering or clamping of the brush is minimized. In the tool 49 a universal motor 50 of elongated narrow form is provided, having a pistol grip 5I and control switch 52 at one end, and a reduction gear mechanism 53 at the other end with a terminal or output shaft 54. On the output shaft 54 is a brush holder 55, as shown in Figs. 1 to 4, being constructed to receive and clamp anyone of the usual size paint brushes with the longitudinal axis of the handle thereof centered on the axis In attaining such centered mounting ofA a brush, such as the brush 30a of Fig. 1, th brush holder 55 is provided with a first centering means 55 (Fig. 2) adjacent to the end of the shaft 54 and operatively engageable with the end 38 of the brush handle 34 to center the same'on the shaft axis, and a cooperating centering and clamping means 51 spaced axially from the centering means 56 and adapted to clamp and center the portion of the brush handle adjacent to the neck 31'or the head 33. The centering meansASB is such that it may be engaged by the handle 34 in an endwise approaching movement of the handle, and in the form shown in Fig. 2 constitutes a substantially conical recess 58 centered on the axis of the shaft 54 and facing away from said shaft. With such a conical surface, the ends of various handles may be readily and easilyv engaged to attain the desired centering action. The centering recess 55, as shown in Figs. 2 and 3. is formed in one end of a generally conical hub 55, the other end of which is reduced. as at 55, and has an axial bore 5| formed therein to embrace the end of the shaft 54. The hub is secured to the shaft 54 by means such as a radial set screw 52 passing through the reduced portion 55 ,of the hub 55.

'I'he clamping andv centering means 51 is also mounted on the shaft 54, for rotation therewith, and where a relatively large body such as the hub 55 is used in the centering means 55. the clamping and centering means 51- is mounted thereon. Thus as shown in Figs. l to 4, the clamping and centering means 51 comprises a pair o'f similar arms 55 secured as by screws 55 on flattened opposite sides ofthe hub 55 so as to extend along opposite sides of the shaft axis. At a considerable distance from the hub 55 the arms 55 have inwardly bent Jaws 55 with Ihandle-engaging arcuate ends 55 at their ends adapted to embrace and properly center a brush handle adjacent to the neck thereof. Preferably these arcuate ends 55 are toothed as at 55'. As herein shown the jaws 55 are bent to an acute angle relation with the main body of the arms 55, and the arms 55 as well as the jaws are formed from a resilient metal such as strips of spring steel. 'I'he arms 55 normally diverge from their clamped positions shown 'in Fig. 1, so that the jaws 55 are separated by a distance suillcient to allow insertion of a brush handle therebetween. Means is provided for urging the Jaws 55 to clamped relation to a brush handle, and in the form shown in Figs. l to 3, this means comprises a clamping ring 15 embracing the two arms 55 and adapted to be slid away from the hub 55 and toward the extreme ends of the arms 55. In this movement, the ring 15 forces the diverging arms toward eachother to engage the jaws with the handle thereby centering the brush inthe holder. It has been found that the Jaws 55 then act with a resilient force to hold the brush handle in the desired endwise engagement with conical centering means 55.

In theform shown in Figs. l to 4, the arms 55 have leal' springs 1I secured thereto adjacent their free ends of the arms, as by rivets 1I', and

the free ends of these leaf springs 1I are located relatively close to each other near the recess 55.

When the end of a brush handle is moved into the recess 55, this handle is ilrst gripped or held between the leaf springs 1I so as to aid in holding the brush in place while the arms 55 are moved to their clamping positions. The springs 1I also aid in centering the end of the brush handle in the event that the user does not properly seat the handle in the recess 55.` If desired, the inner surface of the ring I5 may be cruciform in shape so as to provide interengagement with the arms and thereby prevent rotation of the ring. With this form-the inwardly projecting corners4 15' engage the end of the hub 55 to limit the retraction of the ring 15. Preferably the arms 55 are inwardly flanged as at 12 along the maior portion of their side edges, as shown in Figs. 1 to 3, thereby stiifening the arms and assuring proper and emcient application of the clamping force when the ring 15 is advanced toward the ends of the arms 55. It will be noted. however, that the arms 55 are unfianged immediately adjacent to their point of connection with the hub 55, and it is in this unilanged portion that the exure of the arms takes place.

'I'he arms E5 and the jaws il are so proportioned that the clamping faces CI are relatively close together when the ring is advanced the full length of the arms. thereby to clamp brushes with slender handles while in various intermediate positions of the ring 1l, thicker brush handles are clamped between the jaws. To prevent rearward displacement of the ring 10 in case its forward clamping movement has been insufficient, I provide a series of three or more outward projections or buttons 65' disposed at spaced points along the arms 05 so as to have a slight engagement with the ring I as it is moved along the arms i5. These projections or buttons 65' may be formed in the same stamping operation as the flanges 12 of the arms 55.

The clamping and centering means 51 and the conical centering recess I of the tool shown in Figs. 1 to 4 are so spaced axially of the shaft 54 that they may be operatively engaged with brush handles of various commercial shapes, the operative ends of the jaws Il preferably being spaced from the bottom of the recess 5l a distance of approximately 5 inches. This spacing is of course related to the steepness of the angle of the sides of the recess, and the dimension herein given is predicated upon the use of the angle or proportioning herein shown for the recess 58.

Where a high speed universal motor such as the motor 50 of Fig. 1 is employed, I prefer in the commercial application of the invention, to

use a gear reduction which produces an unloaded speed of substantially 1400 revolutions per minute ln the shaft 54. Such speed is somewhat less than would be indicated as a minimum for short 'bristlel brushes, say 2 inch, and is used advisedly `er and more expansive brushes. Even with a tool having an initial o`r unloaded speed of 1400 R. P. M., the smaller brushes are cleaned quite thoroughly, and by reducing the initial or unloaded speed of thetool as above suggested the problems of properly clamping andwcentering the brushes are materially simplified.

In practice, which a. gearing which gives an output shaft speed of.1400 R. P. M. from an unloaded motor speed of 20,000 R. P. M., the placing of a brush vin the holder causes a reduction in speed which is dependent upon the weight and size of the brush. With such a gearing and such an unloaded motor speed, a relatively small and inexpensive motor may be used, and this reduction in speed is such that'the various larger sizes of brushes, such as those having 3, 4 and 5 inch bristles, are in every instance rotated at a speed exceeding that indicated by the formula as the minimum speed for proper cleaning.

By employing, with the gearing above described, a series wound universal motor known commercially as Type 69, having an unloaded speed of 20,000 R...P. M., and made by Speedway Manufacturing Co., of Cicero; Illinois, I have found that with the various sizes of commercial paint brushes between 21/2 and 5 inch bristle length, the

to said vsatisfactory minimumto avoid danger due to improper centering of the brush. v

It must be contemplated tl .t thebrush will in many cases be mounted with its center of gravity slightly eccentric with respect to the axis of rotation of' the brush holder, but so long as the speed of rotation is maintained relatively close to the figure indicated by the foregoing formula, such v slight eccentricity will be found vto be immaterial.

Such eccentricity will, of course, cause a slight wobbling of the tool, and this wobbling would, in a stationary mounting of the shaft 54 cause a constantly increasing vibration to be set up which -would eventually cause breaking of the brush handle, or displacement ofthe brush. In the portable tool of the present invention, this is avoided, since the .energy of such wobbling of the brush is dissipated by producing a wobbling of the entire tool. In practice it is found that the painters normally grasp and support the tool at the gear casing 53, and that any wobbling of the.

tool is thereby rendered unobjectionable. Thus, with the present tool, absolute accuracy of mounting of thebrush is rendered immaterial, and its use is rendered practical.

In the practice of my invention, with the tool herein shown, the several brushes to be cleaned are first soaked in-a solvent such as turpentlne for a. period depending on the stiffness or hardness of the paint in the brush. A brush is then mounted in the brush holder and the tool is positioned as shown as Fig. 1 of the drawing within a shield or container 90. This container may be of the size or type usually sold as garbage receptacles, the width of the can being sufficient to allow the bristles of a large size brush to be thrown to radial positions as shown in Fig. 1 without touching the sides of the container. The motor 50 is then started so as to rotate the brush about its axis at high speed within the receptacle, and in such rotation the paint and solvent are thrown outwardly from the brush against the side wall of the container, so that the discharged solvent is collected at 9| in the bottom of the container. This collected solvent may then be re-used for subsequent brush soaking operations. f

After a period of rotation of about 30 seconds at the proper speed, as hereinbefore indicated,

it will be found that the brush will be practically dry and that most of the paint will have been removed therefrom. The brush is then rinsed by a similar operation, and to facilitate such rinsing I place a multiple compartment receptacle 92 centrally in the bottom of the container 90. In the compartments of the receptacle 92 a suitable rinse solution such as turpentine is contained, and after the initial cleaning operation the brush is dipped into the relatively clear solvent of the rinse receptacle, and is then rotated within the container 90 as before for a period of from 5 to 20 seconds. Thus the rinse solution is also collected and conserved in the bottom of the large container for subsequent brush soaking operations. After from one to three rinsing operations the brush is found to be clean and relativelyvv dry so as to be ready for use with another type or color of surface coating.

I have found in practice that in normal commercial painting work the brushes canl be cleaned in from 90 seconds to two minutes each, includmg the time required to load andunload the brush, and thatinevery instance thebrushesare in far better condition than when from l0 to 20 minutes has been spent in endeavoring to clean them by prior methods. In fact. with the pres-- ent method, a brush used with green paint may be so thoroughly cleaned. within'less than two minutes. that it may be used immediately and satisfactorily with clear lacquer or clear varnish,

a result which has heretofore been impossible.

Prom the foregoing it will be apparent that the present invention provides a method and means for cleaning paint brushes whereby higher qualvbeused.'

'nimm the use of the presnt invention n marked economy of solventis also efi'ected since thesolventusedasarinseiscollectedasaninci- 'denttothecleaningoperationsothatitmay ity work is assured in the painting operations performed with such brushes. Buch higher quality performance is due in part to the fact that through the use of the present invention all of the encrusted paint from the brush is efectually removed thereby preventing the deposit of such particles on the painted surface. Moreover. the thorough removal of the hardened paint at the base of the brush also restores the bristles of the brush to their full effective length so as to cause a more even and desirable application of the paint.

In addition to the foregoing advantages the present invention prevents the formatlonof undesired blemishes in the painted surface such as are often caused by the retention of paint of an undesired color in the base of the brush. Where brushes are cleaned in accordance with the present invention substantially all of the solvent is removed from -the brush, thereby preventing thinning of the paint and also avoiding the marked inconvenience which often results when such solvent runs down the handle of -a paint brush used in overhead work on to the workers hands and clothes. The present invention is particularly valuable in enamel and varnish work where abwlute cleanliness of the brush is desirable; and it makes it unnecessary for the painter to carry special brushes for each color of enamel and for each type of varnish.

It will also be apparent that the .present lnvention results in a great economy of time inso; far as the cleaning operation perse is concerned, for the present invention enables the brushes to be cleaned much faster than has heretofore been possible. The cleaning operation of the present invention is particularly advantageous by reason of the fact that it may be carried on within the building in which the painting operation is being performed thereby saving the time usually requirediwhen the painter performs the cleaning operation outside of the building. 'I'he economy effected by the present invention also extends to the brushes themselves since it is apparent that cleaning of the brushes by the method and apparatus herein described does not damage the bristles. In addition the present invention obviates the need for trimming the outer layer of bristles to remove the encrusted paint, and by its use prevents dried or stiffened paint from accumulating in the heel or base of the brush. The life of the brush is thereby materially increased and the brushes are maintained in their maximum state of usefulness with the maximum bristle length available at` all times. In many instances the present invention has been, and may be,k utilized to restore old and discarded brushes to a useful state through the removal of stiifened and hardened paint from the heel thereof.

In addition to the foregoing features of' economy with relation to the brushes it will be noted that the present invention also reduces the inof substantially serve as a soaking solution for further cleaning Hence, while I have illustrated and described a preferred embodiment of tool for the practice of my invention, and while I have described the preferred mode of practice of my invention in considerabk detail. it is to be understood that these are capable ofl variation and modincation andlthereforedonotwishtobelimitedtothe precise details set forth, but desire to avail myself of such changes, alterations and variations as fall withintbe purview ofthe following claims:

Iclaimasmyinvention:

l. The method of cleaning accumulated paint or like surface coating material 'from a paint brush having an elongated `handle carrying bristles normally extending substantially parallel to the longitudinal axis of the handle which consista in soaking the brush in a suitable solvent until the paint in said brush has been'softened and dissolved at least in part and rotating said ibrush about substantially the axis of its handle so that the bristles assume positions approximating a radial relation to the axis of such rotation and at such a speed that the dissolved paint and the solvent will move along the bristles and be discharged from the ends thereof.

2. The method of cleaning paint brushes which consists in soaking the brush in a suitable solvent until tlm paint or other surface coating material has been softened and dissolved at least in part and rotating said brush about substantially the longitudinal axis of its handle at a rotative speed revolutions per minute, where L equals the length of the bristles in inches. l

3. The method of cleaning and removing accurmulated paint or like surface coating material from a paint brush which consists in'soaking the brush in a suitable solvent until the paint in said brush has been softened and dissolved at least in part and rotating said brush about substantially thelongitudinalaxisofitshandleatarateof rotation sufficient to bend all of the bristles outwardly away from said axis.

4. The method of cleaning accumulated paint or like surface coating material from a paint brush having an elongated handle carrying bristles normally extending substantially parallel to the longitudinal axis of said handle which consists in soaking'the bristles of the brushin a suitable solvent until the paint in said brush has been softened and dissolved at least in part, and rotating said brush about substantially the axis ofitshandlefromazerospeedu to s f su D a Deedo revolutions per minute, where so that as the rotative speed of the brush increases the bristles adjacent the outer edge of the brush are rst bent outwardly so as to break up the paint about such bent bristles and whereby the bristles are successively bent outwardly away from said axis until finally all of the bristles including the bristles located at said axis are bent outwardly so as to progressively break up the paint in the brush and discharge the solvent and paint from the brush.

5. The method of cleaning paint brushes as defined in claim 4 wherein said rotation of the brush is terminated after a short period and the 5 brush is again dipped in a solvent and again ro tated as defined in claim 4.

WILL E. NASH, JR.

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