US3323162A

US3323162A - Plastic paint brushes

Info

Publication number: US3323162A
Application number: US400395A
Authority: US
Inventors: Laurizio Jeromiah
Original assignee: American Flange and Manufacturing Co Inc
Current assignee: American Flange and Manufacturing Co Inc
Priority date: 1964-09-30
Filing date: 1964-09-30
Publication date: 1967-06-06
Anticipated expiration: 1984-06-06

Description

June 6, 1967 J. LAURIZIO PLASTIC PAINT BRUSHES 2 Sheets-Sheet 1 Filed Sept. 30, 1964 II/IA? l/lfl'lfi'lm l E m INVENTOH 1 (/EEZM/flfl Laue/2m BY C a ATTORNEY June 1967 J. LAURIZIO PLASTIC PAINT BRUSHES 2 Sheets-Sheet S Filed Sept. 30, .1964

INVENTOR ATTORNEY United States Patent M 3,323,162 PLASTIC PAINT BRUSHES Jeremiah Laurizio, New Providence, NJ., assignor to American Flange & Manufacturing Co., Inc., New York, N.Y., a corporation of Delaware Filed Sept. 30, 1964, Ser. No. 400,395 4 Ciairns. (Cl. 15-193) This invention relates to an improvement in the manufacture of brushes and is particularly concerned with an improved construction for paint brushes of the type in which the handle and ferrule component parts thereof are molded ofa synthetic plastic material.

In the manufacture of paint brushes it has been the practice for many years for the bristles to have their inner ends held in what is commonly termed a knot, and for this knot to be mounted in a sheet metal ferrule which, in turn, is fastened to a wooden handle by nails, pins or equivalent fastening means. The ever increasing popularity of using synthetic plastic material for manufacturing a wide variety of products has prompted a number of manufacturers to attempt to develop a paint brush constructed in its entirety from synthetic plastic materials. However, none of these previous efforts has developed such a paint brush that can successfully compete with the prior wooden handle paint brushes. A number of problems present themselves in the development of a successful all plastic brush construction. First of all, an acceptable brush must satisfactorily withstand the severe abuse imposed by the rigorous mechanical action of normal handling. Perhaps just as important, an acceptable brush must not be adversely effected in any way by prolonged submersion in any of a wide range of commercial solvents, cleaners, thinners, and the like, commonly employed in the painting field. Even occasional partial failure in either of the above mentioned respects, such as might be indicated by bristles coming out or loosening of the brush parts, would completely preclude acceptance by the trade. Also not to be overlooked is the fact that in order for an all plastic brush to compete economically with existing wood and metal constructions, it must lend itself to a simple, relatively high speed, injection molding operation. The brush construction of this invention has overcome the problems encountered in the prior efforts to produce an all plastic paint brush and is believed to be a substantial improvement thereover.

A significant obstacle that has heretofore presented itself in attempts to manufacture an all plastic brush construction is the absence of some simple effective means for permanently securing the ferrule to the brush handle. Improved structural qualities have been found to reside in a brush construction wherein a rigid interlocking connection is formed between the handle and the bristles by means of a mass of thermosetting plastic resin. The manufacture of this construction is carried out by covering the inner ends of the bristles, supported within the ferrule, with a mass of semi-liquid synthetic resin. Upon insertion of the handle end within the ferrule, means suitably formed thereon are embedded in the resin, thereby providing a mechanical interlock between the handle and the bristle knot upon the subsequent curing and hardening of the resin. In the prior efforts to produce an all plastic paint brush the ferrule is secured to the handle and to the bristle knot by reliance upon the adhesion of the synthetic resin between the knot and the interior surface of the ferrule. However, extensive testing has proven this bond to be inadequate particularly under severe use conditions where the brush is subjected to the swelling and other deleterious effects of common commercial solvents used in the painting field.

The all plastic brush of this invention successfully overcomes this and other problems in providing an improved construction wherein the brush ferrule is so formed as to be securely and permanently held in interlocking engage- 3,323,162 Patented June 6, 1967 ment with the handle and with the bristle knot. This has been accomplished without reliance upon either the adhesive quality of the synthetic resin or upon separately formed and applied fasteners. Furthermore this interlocking engagement is such as to prevent movement of the ferrule away from the handle and bristle knot not only in a longitudinal direction but also in a lateral direction hence preventing separation of the brush parts by forces causing expansion of the ferrule such as those exerted by the swelling action on the parts caused by solvents and like substances.

Another improved feature of the brush construction of the invention is the manner in which the handle itself is formed so that insertion of the handle into the previously assembled ferrule and bristle knot can be readily and quickly effected without causing the liquid resin to be forced out around the joining surfaces of the handle and the ferrule. The joining end of the handle is provided with a novel venting means for relieving the compression created during this assembly operation which is formed in a simple and economical manner without adding to the number of parts or manufacturing operations.

It is accordingly a principal object of the invention to provide new and improved paint brushes.

Another object is to provide a new and improved brush construction having the handle and ferrule component parts thereof formed from synthetic plastic material.

Still another object is to provide a new and improved plastic brush wherein the detrimental swelling effect of solvents thereupon has been minimized.

A further object is to provide a plastic paint brush construction wherein the ferrule is permanently held in tight interlocking engagement with the handle and bristles.

A further object is to provide improved plastic handles for paint brushes.

A still further object is to provide improved plastic ferrules for paint brushes.

A still further object is to provide a hollow handle brush construction wherein improved means are provided for venting the interior of such handle upon insertion thereof into the bristle knot and ferrule subassernbly.

Other and different objects will in part be obvious and in part pointed out as the description, taken in conjunction with the accompanying drawing, proceeds.

In that drawing:

FIG. 1 is a perspective view of the paint brush in accordance with the invention;

FIG. 2 is a perspective exploded view showing the handle and ferrule with portions of the same cut away for purposes of clear illustration;

FIG. 3 is an end elevational view of the handle portion as shown in FIG. 2;

FIG. 4 is a longitudinal cross-sectional view taken on the longitudinal plane 4-4 in FIG. 1 and looking in the direction of the arrows;

FIG. 5 is a cross-sectional view taken on line 5-5 of FIG. 4 and looking in the direction of the arrows;

FIG. 6 is a detail view, on an enlarged scale, of an end portion of the brush as viewed in FIG. 5;

FIG. 7 is a cross-section view taken of line 77 of FIG. 6 and looking in the direction of the arrows;

FIG. 8 is a cross-sectional view of a modified form of the ferrule taken on line 88 of FIG. 9 and looking in the direction of the arrows;

FIG. 9 is a cross-sectional view taken on line 9-9 of FIG. 8 and looking in the direction of the arrows;

FIG. 10 is a cross-sectional view of a further ferrule modification taken on line 1010 of FIG. 11 and looking in the direction of the arrows;

FIG. 11 is a sectional view taken on line 1111 of FIG. 10 and looking in the direction of the arrows;

FIG. 12 is a cross-sectional view of still another modified form of the ferrule taken on line 12-12 of FIG. 13 and looking in the direction of the arrows; and

FIG. 13 is a sectional view taken on line 13-13 of FIG. 12.

The complete brush assembly as shown in FIGS. 1 and 4 has as its principal parts a handle 1, a ferrule 2, and a bristle knot 3. The handle 1 is formed of a synthetic plastic material and comprises an elongated hollow hand grip 4 flaring outwardly at one end into a curved base wall 5, which, in turn, has extending longitudinally outwardly therefrom a rectangular sleeve 6 having sidewalls 8 and endwalls 7. For additional strength and rigidity, a pair of

cross members

9 and 10 extend outwardly from the base 5 and are secured to and interconnect opposing sidewalls 8. The outermost edge of the sleeve 6 has a slight inward bevel 11, and has a plurality of spaced apart and inwardly formed

lugs

12 and 13 integrally formed on the end walls 7 and on the sidewalls 8. These lugs are initially molded as straight longitudinal continuations of the sleeve walls 7 and 8, and are subsequently bent over so as to extend laterally inwardly as shown. To facilitate this bending operation, the lugs are formed with a lesser cross sectional thickness than the sleeve walls with the outer surface of the lugs extending flush with the outer surface of the sleeve to form ledges 17 when the lugs are bent inwardly as shown in FIGS. 6 and 7. The junction of the sleeve 6 and the curved base wall 5 is surrounded by a longitudinally outwardly opening channel 14 which has a bottom 15 formed by a portion of said base wall 5, and inner and outer sides formed by the outer surface of sleeve 6 and a lip 16 laterally spaced from said sleeve and secured atone end to the base wall 5. For purposes more fully explained hereafter a wall of the sleeve 6 has formed therein a slot 23 extending longitudinally inwardly from the free edge 11 to a point spaced from the lip 16 of channel 14.

The ferrule 2 is preferably molded of a synthetic plastic material and is shown in detail in FIGS. 2 through 7 as being a hollow member having both ends open and having opposing pairs of

side walls

18 and 19. The ferrule 2 has a rectangular cross sectional configuration corresponding to the cross sectional configuration of the handle sleeve 6 and has an interior surface so dimensioned so as to snugly surround the outer surface of that sleeve. The ferrule is substantially longer than the sleeve 6 and terminates at its outer or bristle end in a cross sectionally thickened lip 20, which has an end surface 21 and an elongated interior surface 22. The inner surface 24 of the lip adjacent to the inner surface of

sides

18 and 19 is beveled as clearly shown in FIGS. 6 and 7 and forms a relatively sharp inner edge 25 at the point of intersection of

surfaces

22 and 24. Also formed on the interior surface of the ferrule 2 is a pair of opposed longitudinally extending ribs 26, preferably centrally positioned on the interior surfaces of the ferrule walls 19. Although the lateral inward extent to which the ribs 26 protrude, many vary within limits, it is desirable from a manufacturing view point, that the ribs not extend beyond the lateral interior lip surface 22.

The assemblying of the various components into a finished brush construction is carried out by first inserting the bristle knot 3, which is suitably performed and provided with spacer strips as shown at 27 in FIG. 7, into the ferrule 2 in such a manner that the ends 28 of the bristles are positioned in alignment with the edge 25 of the lip 20. The enlarged gripping area presented by the lip surface 22 acts to hold the bristles firmly during this stage of the manufacturing process. This particular feature has overcome what has become a problem in the prior art constructions since the bristles now commonly made from nylon are not effectively frictionally held by a narrow relatively smooth plastic surface. For this reason the surface 22 has been elongated, this presenting a greater holding area for the bristle end portions. Also the lengthened surface 22 helps to prevent the bristles from flaring laterally outwardly at the ferrule end 21. Such outward flaring is undesirable in the paint brush art both in terms of functions and appearance.

The next step is to inject into the open end of the ferrule a quantity of semi-liquid adhesive, a non-limiting ex ample of which is an epoxy resin. The usual amount of adhesive applied is just enough to cover the ends 28 of the bristle so that the end portions of the bristles are firmly bonded within the ferrule. After the initial adhesive application has cured, this subassembly is then subjected to a further bristle trimming and finishing operation.

A second application of the semi-liquid mass 29 is then inserted in the open end of the ferrule on top of the previous application filling the ferrule to a level substantially above the lugs 26. The sleeve 6, of the handle 1 is then inserted in the ferrule, fitting snugly therewithin, and the respective parts moved longitudinally together until the inner end 32 of the ferrule abuts the bottom wall 15 of channefl 14 on the handle end portion. The inner end 32 of the ferrule is beveled to facilitate the insertion of the ferrule onto sleeve 6. As the sleeve 6 slides into the ferrule 2, the air confined within the sleeve and the ferrule is com pressed and unless released would force the adhesive out around the bristles and create undesirable pressure on the ferrule. However this confined air is vented through the slot 23 as the parts are moved together. Continued movement of the sleeve into the ferrule embeds the

lugs

12 and 13 in the adhesive mass 29 when the ferrule end 32 is fully seated against the bottom 15 of the channel 14. It is to be noted here that the two applications of adhesive above described could be consolidated into a single applica tion without departing from the scope of the invention. This would simply mean that the bristle finishing operation would be performed on the completed brush rather than on the ferrule and bristle subassembly. Upon final curing of the second application of adhesive mass 29 a very strong hard mass is formed as shown in FIGS. 4, 6 and 7. In order to form a permanent, rigid, interlocking engagement between the bristle knot 3 and the handle 1, it is important that the adhesive mass 29 extend above and completely cover the inturned lugs 12 and 13 thus insuring against any possibility of the lugs breaking out of the adhesive mass. This engagement is further strengthened by the particular configuration assumed by the surface of the adhesive mass upon curing. That configuration comprises a depressed central portion 30 bordered by a raised peripheral portion 31 providing added strength above the lugs where it is most meeded and decreasing in thickness toward the less critical center area where the volume of the mass can be reduced without adversely affecting the structural qualities of the brush.

In addition to securely joining the handle 1 and the bristle knot 3, it is essential that the ferrule 2 be permanently secured to the handle in tight relationship and at the same time to be securely interlocked to the bristle knot so that lateral outward movement of any portion of the walls of the ferrule is prevented. It is this part of the brush 1 assembly which is most susceptible to the damaging effects of the ordinary solvents to which the brush is ultimately subjected. The resulting reaction of the plastic ferrule when submerged in ordinary solvents is to swell to a greater internal dimension thus pulling laterally away from the sides of the adhesive mass 29. Subsequent use of the brush when the ferrule portion is in this swelled condition causes the ferrule to be worked away from the handle in a longitudinal direction and of course eventually to be completely separated therefrom. Thus it can be seen that the problem is to secure the ferrule to the handle and to the bristle knot in such a manner that both lateral and longitudinal movement of the ferrule with respect to the handle sleeve will be effectively precluded. It has by now become recognized that the degree of adhesion which exists between the mass 29 and the interior surface of the ferrule 2 is wholly inadequate for this purpose. The solution to this problem lies in the novel construction disclosed in this invention as illustrated particularly in FIGS. 6 and 7 encases the

lugs

12 and 13 but also completely encases the ribs 26. The result is a portion of the permanently hardened mass as indicated at 33 in FIG. 7 abutting the interior surface of the ferrule 2 and lying between the upper surface of the rib 26 and the downwardly facing surface of the

lugs

12 and 13. Also abutting the interior surface of the ferrule is a portion 34 of the adhesive mass lying below the lower surface of the lug 26 and extending at 35 into and filling the V-shaped groove formed by the beveled surface 24.

From the foregoing it can be readily seen that lateral outward expansion of the ferrule is prevented throughout its inner peripherial edge by the lip 16 and throughout its outer periphcrial edge by the adhesive mass portion 35 which is interlocked against the beveled surface 24. So long as the side walls of the ferrule are restrained from moving laterally away from the handle sleeve 6, longitudinal movement of the ferrule away from the handle is effectively prevented by the lower surface of rib 26 which bears against the adhesive mass portion 34. This mechanical interlock between the hardened adhesive mass 29 and the ferrule 22 prevents separation of the brush assembly and the ferrule in both lateral and longitudinal directions. At the same time this improved construction is brought about without complicating to any material exent the simple manufacturing process normally employed in molding the respective plastic parts.

The ferrule may be molded of the same synthetic plastic material as that from which the handle is molded if desired, without departing from the scope of the invention. However, to further enhance the solvent resistant characteristic of the brush of the invention it has been found that an improved construction results from molding the ferrule of a plastic material having somewhat greater solvent resistance than the handle. A nonlimiting example is the combination of an acetal ferrule and a polypropylene handle. The improved results in this respect flow from the fact that the more solvent resistance acetal material from which the ferrule is molded is characterized by superior dimensional stability and hence less susceptible to severe swelling upon submersion in chemically active organic solvents, cleaners, thinners and the like. The handle, however, is not subjected to quite the same abuse as is the ferrule in this respect. Swelling of the handle component within reasonable limits does not adversely effect the overall brush construction as does swelling of the ferrule. When a brush so constructed is submerged in an organic solvent for a prolonged period this difference is dimensional stability of the handle and ferrule has an advantage. Since the handle end portion swells or expands more than the ferrule 2, the engagement between the two parts actually becomes tighter upon swelling, thus further insuring against their separation. The polypropylene material from which the handle is formed also results in both a cost and a manufacturing advantage in that it is easier to mold and the operation of bending over the

lugs

12 and 13 is facilitated by the use of the somewhat softer material.

A modified ferrule 40 is shown in FIGS. 8 and 9 which is similar in all respects to the ferrule 2 of the preferred embodiment with the exception that a peripheral groove 41 is formed in the interior surface of the walls 7 and 8 slightly above the beveled surface 24 for receiving a portion of the adhesive mass to provide an additional interlocking joint between the adhesive mass and the side walls of the ferrule. It is to be noted that the V-shaped groove formed by the beveled surface 24 is also shown as extending peripherally in this embodiment.

FIGS. and 11 depict another modification wherein the ferrule 51 is formed with a plurality of spaced recesses 51 formed in the interior surface of the side walls and ex tending peripherally of said ferrule which provide the required mechanical interlock.

In FIGS. 12 and 13 a still further modified ferrule 60 is shown having a plurality of spaced projections 61 which extend from the interior surface of the side walls and which serve to lock the ferrule to the handle.

Since further variations and modifications in the brush construction as described in the foregoing specification and shown in the accompanying drawing may readily suggest themselves to those skilled in the art, it is to be understood that the same can be made without departing from the spirit and scope of the invention. It is accordingly intended that all matter contained in the above description or shown in the accompanying drawing shall be interpreted in an illustrative and not a limiting sense.

Having described my invention what I claim as new and desire to secure by Letters Patent is:

1. In brush construction, a hollow, one-piece handle molded of synthetic plastic material having an elongated hand grip portion terminating at one end in a laterally out- Wandly flared base wall, a hollow substantially rectangular sleeve extending longitudinally outwardly from said base wall and terminating in a free end, said sleeve including opposed side walls and opposed end walls, a laterally extending shoulder surrounding said sleeve, bristles adhesively bound together adjacent one end in an adhesive mass and extending longitudinally outwardly of said sleeve, a plurality of laterally extending adhesive engaging surfaces provided on said sleeve for effecting interlocking engagement between said sleeve and said adhesive mass, a portion of said adhesive mass interposed between said one end of said bristles and said free end of said sleeve, a hollow tubular ferrule having an inner end and an outer end and including opposed side walls and opposed end walls engaged about said sleeve, said ferrule extending longitudinally outwardly of said sleeve so as to surround said adhesive mass and said bound end of said bristles and structural interlocking means including two separate ferrule surfaces integrally formed on the inner surface of said ferrule side walls positioned longitudinally outwardly of said sleeve end to effect lateral and longitudinal interlocking engagement with said adhesive mass whereby said ferrule inner end is held against displacement away from said shoulder and said ferrule outer end is held in contact with said bristles.

2. In brush construction as in claim 1, wherein a portion of said adhesive mass extends laterally outwardly between said two surfaces.

3. In brush construction, a hollow, one-piece handle molded of synthetic plastic material having an elongated hand grip portion terminating at one end in a laterally outwardly flared base wall, a hollow substantially rectangular sleeve extending longitudinally outwardly from said base wall and terminating in a free end, said sleeve including opposed side walls and opposed end walls, a laterally extending shoulder surrounding said sleeve bristles adhesively bound together adjacent one end in an adhesive mass and extending longitudinally outwardly of said sleeve, a plurality of laterally extending adhesive engaging surfaces provided on said sleeve for effecting interlocking engagement between said sleeve and said adhesive rnass, a portion of said adhesive mass interposed between said one end of said bristles and said free end of said sleeve, a hollow tubular ferrule having an inner end and an outer end and including opposed side walls and opposed end walls engaged about said sleeve, said ferrule extending longitudinally outwardly of said sleeve, so as to surround said adhesive mass and said bound end of said bristles, first structural interlocking means integrally formed on the inner surface of said ferrule side walls posi tioned longitudinally outwardly of said sleeve end and longitudinally inwardly of said ferrule outer end to effect lateral interlocking engagement with a first portion of said adhesive mass and second structural interlocking means integrally formed on the inner surface of said ferrule side walls positioned longitudinally outwardly of said sleeve end and longitudinally inwardly of said ferrule outer end to effect longitudinal interlocking engagement with a second portion of said adhesive mass whereby said ferrule inner end is held against longitudinal displacement away from said shoulder and said ferrule outer end is laterally held in contact with said bristles.

4. In brush construction as in claim 3, wherein said first adhesive portion has a ferrule engaging surface angularly disposed with respect to a ferrule engaging surface on said second adhesive portion.

References Cited UNITED '8 10/1958 Hardman et 'al. -15193 4/1964 Daw 15192 11/1964 Hardman et al. 15192 7/1965 Weiss et al. 15-192 2/1966 Malpas 15--193 FOREIGN PATENTS 3/ 1964 Australia. 12/ 1955 Belgium.

6/1962 Ger-many. 2/ 1962 Great Britain. 7/ 1963 Great Britain.

CHARLES A. WlLLMUTI-I, Primary Examiner.

' PETER FELDMAN, Assistant Examiner.

Claims

1. IN BRUSH CONSTRUCTION, A HOLLOW, ONE-PIECE HANDLE MOLDED OF SYNTHETIC PLASTIC MATERIAL HAVING AN ELONGATED HAND GRIP PORTION TERMINATING AT ONE END IN A LATERALLY OUTWARDLY FLARED BASE WALL, A HOLLOW SUBSTANTIALLY RECTANGULAR SLEEVE EXTENDING LONGITUDINALLY OUTWARDLY FROM SAID BASE WALL AND TERMINATING IN A FREE END, SAID SLEEVE INCLUDING OPPOSED SIDE WALLS AND OPPOSED END WALLS, A LATERALLY EXTENDING SHOULDER SURROUNDING SAID SLEEVE, BRISTLES ADHESIVELY BOUND TOGETHER ADJACENT ONE END IN AN ADHESIVE MASS AND EXTENDING LONGITUDINALLY OUTWARDLY OF SAID SLEEVE, A PLURALITY OF LATERALLY EXTENDING ADHESIVE ENGAGING SURFACES PROVIDED ON SAID SLEEVE FOR EFFECTING INTERLOCKING ENGAGEMENT BETWEEN SAID SLEEVE AND SAID ADHESIVE MASS, A PORTION OF SAID ADHESIVE MASS INTERPOSED BETWEEN SAID ONE END OF SAID BRISTLES AND SAID FREE END OF SAID SLEEVE, A HOLLOW TUBULAR FERRULE HAVING AN INNER END AND AN OUTER END AND INCLUDING OPPOSED SIDE WALLS AND OPPOSED END WALLS ENGAGED ABOUT SAID SLEEVE, SAID FERRULE EXTENDING LONGITUDINALLY OUTWARDLY OF SAID SLEEVE SO AS TO SURROUND SAID ADHESIVE MASS AND SAID BOUND END OF SAID BRISTILES AND STRUCTURAL INTERLOCKING MEANS INCLUDING TWO SEPARATE FERRULE SURFACES INTEGRALLY FORMED ON THE INNER SURFACE OF SAID FERRULE SIDE WALLS POSITIONED LONGITUDINALLY OUTWARDLY OF SAID SLEEVE END TO EFFECT LATERAL AND LONGITUDINAL INTERLOCKING ENGAGEMENT WITH SAID ADHESIVE MASS WHEREBY SAID FERRULE INNER END IS HELD AGAINST DISPLACEMENT AWAY FROM SAID SHOULDER AND SAID FERRULE OUTER END IS HELD IN CONTACT WITH SAID BRISTLES.