US3276063A

US3276063A - Paint brush

Info

Publication number: US3276063A
Application number: US507753A
Authority: US
Inventors: Richard S Harrison
Original assignee: TS Simms and Co Ltd
Current assignee: TS Simms and Co Ltd
Priority date: 1965-11-15
Filing date: 1965-11-15
Publication date: 1966-10-04
Anticipated expiration: 1983-10-04

Description

Oct. 4, 1966 R38. HARRISON 3,276,063

PAINT BRUS H Filed Nov. 15 1965 FIGS INVENTOR. RICHARD S. HARRISON ATTORNEYS United States Patent 3,276,063 PAINT BRUSH Richard S. Harrison, Lancaster, New Brunswick, Canada, assignor to T. S. Simms & Co. Limited, New Brunswick, Canada Filed Nov. 15, 1965, Ser. No. 507,753 4 Claims. (Cl. -171) This invention relates to the manufacture of paint brushes and is particularly concerned with a method of attaching brush ferrules to plastic handles.

A recent trend in the manufacture of paint brushes has been to employ plastic rather than wooden handles. This trend has recently received impetus through the promotion of polypropylene as handle material. The price of this particular plastic has made the plastic handle competitive in price with the wooden handle. However, due to the incompressibility of polypropylene and other plastics, certain manufacturing difficulties have been encountered in attaching brush ferrules to the handles. As is well known to those in the trade, the term ferrule is applied to the mild steel band which is used to hold the bristle knot at one end and the handle at the other. The two common methods of holding the handle within the ferrule has been to drive short nails through the flat faces of the ferrule and into the handle or to use a crimper as to displace portions of the fiat faces of the ferrule into the body of the handle. It has been found that while the nailing of ferrules to plastic handles has given a good tensile and bonding strength, the nails cannot be made to remain completely submerged in the plastic. The plastic displaced by the nail causes a ridge of plastic to build up under the ferrule whereby to lift the ferrule away from the handle and expose the sharp edges of the ferrule. This effect not only endangers the user, but is detrimental to the appearance of the brush as well.

Crimping also causes plastic displacement and in this case, the lifting of the ferrule by the upwelled plastic reduces the holding strength of the crimps. For this reason, the crimping of ferrules into plastic handles has been limited to smaller brushes up to two inches in width. With larger brushes the greater width of the ferrules across the flats of the brush has caused the centremost crimps to lift entirely free from the depressions in the plastic. Even with the smaller brushes, the holding strength of the crimps has been marginal.

As suggested above, the manufacturing difficulties encountered in using plastic handles have been largely due to the incompressibility of plastic. Where nails are used, the resultant upward bulging of the plastic, while not always interfering with the holding strength of the nails, raises the edges of the ferrule to present a hazard to the user and to make the brush unattractive in appearance. In the case of crimping, the bulging of the plastic reduces the holding strength of the crimps so that brushes wider than two inches cannot be crimped at all and crimping of the smaller brushes has not been entirely satisfactory.

It is, therefore, an object of this invention to provide an improved method of manufacturing paint brushes with plastic handles.

It is a more specific object of the invention to provide a method of crimping ferrules to plastic brush handles which avoids the difficulties .previously encountered in crimping operations due to the incompressibility of the plastic.

It is a further and related object of the invention to provide a method of crimping ferrules to brush handles which is adapted to the manufacture of brushes of any size.

Patented Oct. 4, 1966 "ice It is a still further object of the invention to provide a paint brush in which the ferrule is attached to the plastic handle by crimps of particular type and location.

The above and further objects of the invention are gained by crimping ferrules to plastic handles along the side edges of the brushes. In a preferred embodiment of the invention the crimping is carried out at the corners of the ferrule.

The above and further objects of the invention and the method in which these objects are achieved will be more thoroughly understood from the following description of preferred embodiments of the invention as read in conjunction with the accompanying drawings.

In the drawings,

FIG. 1 is a perspective view of a paint brush having a plastic handle and manufactured in accord with a first preferred embodiment of the invention;

FIG. 2 is an enlarged view of a portion of FIG. 1 to illustrate in greater detail the location and nature of the crimps holding the ferrule to the handle;

FIG. 3 is an enlarged vertical cross-sectional view taken along the line 33 of FIG. 1 and further showing a crimping die in the action of forming a crimp in the ferrule;

FIG. 4 is an enlarged view of a portion of FIG. 3; and

FIG. 5 is a view similar to the right-hand end of FIG. 3 but showing an alternative form and position of crimp.

Referring to FIG. 1, the paint brush illustrated essentially consists of a knot of bristles or other filling material 10, a mild steel ferrule 12, and a handle 14. In this regard, it will be appreciated that these three items are the normal components in any paint brush and that the present invention relates to the particular manner illustrated for attaching the ferrule to the handle.

Prior to the present invention, the common methods of fixing the ferrule to the handle have been to drive nails or form crimps in the

flat faces

12a and 12b of the ferrule. Either of these methods has served well in fixing ferrules to wooden handles but with the recent introduction of plastic handles, both methods have disadvantages. More particularly, the crimping operation which is now preferred by most brush manufacturers has proved to be quite inadequate in fixing ferrules to plastic handles, particularly with the larger brushes.

The difiiculties met heretofore have been due to two factors, namely, the practice of forming the crimps in the flat faces of the ferrule and the incompressibility of plastic. It has been found that when the crimps are formed in the ferrule as to drive small areas of the ferrule material downwardly into the brush handle, the incompressibility of the plastic has caused the latter to flow upwardly around the downwardly displaced ferrule material. This upward welling of the plastic has, in turn, tended to lift the ferrule away from the handle body, therefore reducing the actual bite effected by the crimps. This effect has been found to be most serious in brushes over two inches in width as the greater flexibility of the wider ferrule has resulted in a complete lifting away of the ferrule, particularly at the centre thereof. Even in the case of the smaller brushes, the strength with which the handle is gripped by the crimped ferrule has been so poor that it has been possible to very easily tear the ferrule off the handle when painting in the normal manner.

In accord with the present invention, the above noted difficulties are overcome by forming crimps along the side edges of the brush. By so doing, not only are the detrimental effects due to the incompressiblity of the plastic avoided but this same feature is actually used to good advantage. The upward welling of the plastic is used as a means of stretching the fiat faces of the 3 ferrule as to pull them down tightly against the handle body. This stretching of the flat faces of the ferrule in turn tends to hold the crimps formed in the ferrule material within the detents formed in the plastic as the crimps are developed. Apart from the surprisingly much greater holding strength in the crimps, the appearance of the brush is improved because there are no crimps on the flat main faces of the ferrule and these flat areas lie tightly against the handle body. This has the further beneficial effect of avoiding the exposure of ferrule edges which might endanger the brush user.

In accord with the preferred embodiment of the invention as shown in FIGS. 1 to 4, the crimps the crimps 16 are formed at the corners of the ferrule. This is a preferred expedient for two reasons. Firstly, almost all ferrules are formed with an overlap at one side edge of the brush so that crimps formed along the centre line of the side edge would have to penetrate two thicknesses of material. Secondly, centre line crimps offer points around which the ferrule might pivot during the normal painting action. However, it should be clearly understood that the present invention contemplates crimps effected anywhere in the side edges of the ferrule as in all cases the desired stretching of the flat faces of the ferrule is achieved.

In forming the crimps at the preferred corner locations, the crimping operation is carried out with vertical travelling dies as shown in FIG. 3. Where the corners are round, which is the normal configuration, the dies contact the corners at the points where the radiants which extend at 45 to the plane of the handle contact the corners. This is shown in FIG. 4. As also shown in FIG. 4, the resultant Welling up of the plastic takes place largely at point 18, i.e. below the crimp, and tends to push the side edge of the ferrule slightly outward which contributes to the stretching of the

flat faces

12a and 12b of the ferrule. Ideally, the vertical travelling die is driven to a depth in the plastic which will cause the majority of the rebounding plastic to push outwardly along those radiants which extend approximately at 30 to the plane of the handle which lie closest to the midplane of the handle so that the horizontal component of the force exerted by this upwelling plastic will be suf- Iicient to stretch the flat faces of the ferrule but not so great as to push the side edges of the ferrule out of the recesses formed in the plastic by the crimps. The crimp 16a shown in FIG. '5 is made on the approximate centre line of the side edge of the ferrule and adequately serves to stretch the flat faces of the ferrule to gain the advantages of the present invention. As mentioned above, however, this centre line crimp will on one side of the brush have to be passed through two thickenesses of ferrule material and it also tends to set up points about which the ferrule might pivot when the brush is used in the normal fashion. :Further, the centre line crimp must be formed with horizontal travelling dies and as most brush manufacturing machines move brushes along the flat faces of the ferrule with the length of the brush at right angles to the direction of motion, the horizontal travelling dies would be more cumbersome than vertical travelling dies. It will be appreciated that it is within the scope of this invention that side edge crimps may be formed positioned at other than the corners or centre line of the side edges as in all cases the desired stretching of the flat faces of the ferrule would be achieved. The invention resides in the concept of effecting the crimps anywhere in the side edges although the preferred embodiment consists of effecting the crimps at the corners.

What I claim as my invention is:

1. A paint brush comprising a plastic handle having an elongated handle grip portion and terminating inan integral ferrule receiving body portion, said body portion having opposed elongated flat faced parallel side Wall surfaces and shorter curved end wall surfaces, thereby affording four curved corners substantially located at the points where the flat side wall surfaces meet the curved end wall surfaces, a tubular metal ferrule tightly engaged about the surfaces of said side walls and said end walls, and means for holding said ferrule on said handle, said holding means consisting of four crimps, one at each of said curved corners, each of said crimps being of a depth in said body portion suflicient to cause outward Welling of plastic material adjacent to each of said crimps whereby said outward Welling tends to push the end wall portions of the ferrule slightly outward thereby resulting in a stretching of the ferrule along the flat faces of said side wall surfaces.

2. A paint brush comprising a plastic handle having an elongated handle grip portion and terminating in an integral ferrule receiving body portion, said body portion having opposed elongated flat faced parallel side wall surfaces and shorter rounded end wall surfaces, thereby affording four curved corners substantially located at the points where the flat side wall surfaces meet the rounded end wall surfaces, a tubular metal ferrule tightly engaged about the surfaces of said side walls and said end walls, and means for holding said ferrule on said handle, said holding means consisting of four crimps, one at each of said curved corners, each of said crimps being of a depth in said body portion sufiicient to cause outward Welling of plastic material adjacent to each of said crimps whereby said outward Welling tends to push the end wall portions of the ferrule slightly outward thereby resulting in a stretching of the ferrule along the fiat faces of said side wall surfaces, said crimps being formed in said curved corners at points located by radiants commencing at the centre about which said rounded end walls are generated and extending at 45 to said fiat parallel side wall surfaces.

3. A method of attaching a tubular metal ferrule to a plastic paint brush handle having an elongated handle grip portion and terminating in an integral ferrule receiving body portion, said body portion having opposed elongated flat faced parallel side wall surfaces and shorter curved end wall surfaces, thereby affording four curved corners substantially located at the points where the flat side wall surfaces meet the curved end wall surfaces, said method comprising the steps of sliding said ferrule onto said ferrule receiving body portion and fixing said ferrule to said body portion by crimping said ferrule at each of said four curved corners to a suifioient depth to cause outward Welling of plastic material adjacent to each of said crimps whereby said outward Welling tends to push the end wall portions of the ferrule slightly outward thereby resulting in .a stretching of the ferrule along the flat faces of said side wall surfaces.

4. A method of attaching a tubular metal ferrule to a plastic paint brush handle having an elongated handle grip portion and terminating in an integral ferrule receiving body portion, said body portion having opposed I elongated flat faced parallel side wall surfaces and shorter rounded end wall surfaces, thereby affording four curved corners substantially located at the points where the flat side wall surfaces meet the rounded end wall surfaces, said method comprising the steps of sliding said ferrule onto said ferrule receiving body portion and fixing said ferrule to said body portion by crimping said ferrule at each of said four curved corners to a suflicient depth to cause outward Welling of plastic material adjacent to each of said crimps whereby said outward Welling tends to'push the end wall portions of the ferrule slightly outward thereby resulting in a stretching of the ferrule along the flat faces of said side wall surfaces, said crimps being formed in said curved corners at points located by radiants commencing at the centre about which said rounded end walls are generated and extending at 45 to the said fiat parallel side wall surfaces.

(References on following page) 6 References Cited by the Examiner FOREIGN PATENTS U I STATES PATENTS 1,311,937 11/1962 France.

582,657 11/19'4 6 Great Britain. 1,436,916 11/1922 Shulman et a1. 300-21 1,767,349 /1930 Cross 15--143 5 CHARLES A. WI LLMU'IH, Primary Examiner, 2,854,684 10/1958 Hardman et a1. 15193 PETER FELDIMAN, Assistant Examiner.

Claims

1. A PAINT BRUSH COMPRISING A PLASTIC HANDLE HAVING AN ELONGATED HANDLE GRIP PORTION AND TERMINATING IN AN INTEGRAL FERRULE RECEIVING BODY PORTION, SAID BODY PORTION HAVING OPPOSED ELONGATED FLAT FACED PARALLEL SIDE WALL SURFACES AND SHORTER CURVED END WALL SURFACES, THEREBY AFFORDING FOUR CURVED CORNERS SUBSTANTIALLY LOCATED THEREBY THE POINTS WHERE THE FLAT SIDE WALL SURFACES MEET THE CURVED END WALL SURFACES, A TUBULAR METAL FERRULE TIGHTLY ENGAGED ABOUT THE SURFACES OF SAID SIDE WALLS AND SAID END WALLS, AND MEANS FOR HOLDING SAID FERRULE ON SAID HANDLE, SAID HOLDING MEANS CONSISTING OF FOUR CRIMPS, ONE AT EACH OF SAID CURVED CORNERS, EACH OF SAID CRIMPS BEING OF A DEPTH IN SAID BODY PORTION SUFFICIENT TO CAUSE OUTWARD WELLING OF PLASTIC MATERIAL ADJACENT TO EACH OF SAID CRIMPS WHEREBY SAID OUTWARD WELLING TENDS TO PUSH THE END WALL PORTIONS OF THE FERRULE SLIGHTLY OUTWARD THEREBY RESULTING IN A STRETCHING OF THE FERRULE OUTWARD FLAT FACES OF SAID SIDE WALL SURFACES.