US3357038A

US3357038A - Brush apparatus

Info

Publication number: US3357038A
Application number: US573575A
Authority: US
Inventors: Williamson Burr; Jr John L Voellmicke; Vello H Ebrok
Original assignee: Danline Manufacturing Co
Current assignee: Danline Manufacturing Co
Priority date: 1966-08-19
Filing date: 1966-08-19
Publication date: 1967-12-12
Anticipated expiration: 1984-12-12

Description

Dec. 12, 1967 B. WlLLlAMSON ET AL 3,357,038

BRUSH APPARATUS 2 Sheets-Sheet 1 Filed Aug. 19, 1966 INVENTORS' Ve/lo H. Ebrok /o W ATTORNEYJ Dec. 12, 1967 B, AMS N ET AL 3,357,038

BRUSH APPARATUS 2 Sheets-Sheet 2 Filed Aug. l9, 1966 INVENTORS Burr WI'I/Ibmson John L l/oel/mfcke, J1:

l/el/o H. Ebrok ATTORNEYS United States Patent ABSTRACT OF THE DISCLOSURE Rotary brushes having rotatable bases, strips having bristle tuft receiving apertures and collars mounted on the bases, capped tuft plugs squeezed tightly within the apertures and collars, and bristles welded within the plugs and the method of welding plugs and bristles are described herein.

This invention concerns bristle tufts, brushes, and brush assemblies and methods for their construction. The articles described herein are primarily intended for use in rotary brushes, which are conventionally used in pick-up brooms or street sweepers, and which are widely used for cleaning industrial areas, urban streets and airport runways and for removing snow.

In rotary brushes for cleaning industrial floors, runways and streets, there have been developed many improvements, which facilitate maintenance of sweeping equipment, which improve the quality of operations and results, and which increase brush life. One example of recent developments in this field is United States Patent No. 3,228,053, which was issued on Jan. 11, 1966. The quest goes on for better, stronger, easier to assemble, and more economical rotary sweepers; and the present invention offers improvements in bristles, in grouping of bristles, in brushes, and in brush assemblies, which meet demands for improved products and for more economical methods of assembly.

The present brush employs oriented plastic bristles which are stretched after they are formed. The oriented bristles are tough and resilient, and the bristles maintain their alignment in tufts to create a desirable increased snap or propulsive thrust as the grouped bristles are rotated upward out of contact with a runway or street. The oriented plastic bristles have a good tensile strength and a desirable modulus of elasticity; moreover, the bristles are neither prone nor subject to fatigue.

In order to achieve optimum sweeping performance, it is important that the plastic bristles have a stifl'ness characteristic sufficient to impart a flipping action to debris on the surface being swept. Normally, when plastic bristles are dispersed uniformly around a broom, each bristle acts individually and does not achieve its maximum effectiveness. However, it has been found that when the bristles are grouped in tufts and are tightly confined at the tuft base, each bristle mutually supports other bristles in the tuft and imparts a much superior stiffness without dilatoriously effecting the fatigue resistance of the bristles. Actual tests have shown that plastic bristles so grouped and tufted will leave only about half the amount of debris on the road as the same quantity of bristles uniformly distributed throughout the broom. For instance, in one test, using identical pressure on the surface being swept and identical broom speeds, the tufted plastic bristles left a residue of 11.95%, while the uniformly dispersed plastic bristles in a spirally wound strip left a residue of 20.80%. Tufted wire bristles mounted in exactly the same manner left 17.10% residue.

It is, therefore, desirable and important in order to obtain maximum results from the bristles to group them and hold them tightly in a holding means. The central core structure, for instance, as shown in the aforementioned United States Patent No. 3,228,053, must be fabricated of steel or some other rigid material in order to transmit the proper forces. At some point the plastic bristles must be fastened to the central core structure. Again, at this point, it is desirable and important that there be no relative motion between the plastic bristles and the metallic structure, or both the plastic and the metal would be subject to excessive wear, which eventually would loosen the hold of the metal on the tuft of plastic bristles and, consequently, would decrease the effective stiffness which is so desirable.

It has been found that if the plastic bristles are inserted in a metallic holding means in such a fashion that the metal is stretched within its elastic limit as the bristle is inserted therein, or the bristles themselves are looped in a well-rounded bend and held so that the elastic limit of the bristle is not exceeded, then a retaining force is developed by the properties of the material in such a fashion that the tuft is held firmly throughout the life of the broom. The co-action between the metallic holding means and the plastic bristle is similar whether the holding force is developed through a slight stretching of the metal or the bending of the plastic bristle.

In one embodiment of this principle, the plastic bristles are fused or connected to plastic plugs or holding means, and these plugs are used to stretch metal collars which hold the plugs. In this case, it is beneficial to construct bristles and holding means or plugs from similar or identical materials. Oriented plastics are extremely useful. A suggested material for construction of the bristles and bristle holders is polypropylene, although other alpha olefin homopolymers or copolymers may be used less advantageously. Use may be made of other elastomeric plastic bristles such as nylon, polyvinyl chloride, and polyurethane bristles, etc.

Since it is important that neither bristle segments nor bristles be thrown on streets, floors or runways, it is necessary that bristle holding means or joints between bristles and holding means be as strong as individual bristles. Airport sweepers particularly require strong joints, since they rotate at 600 r.p.m. By using similar materials in the holding means and bristles, joint strength is enhanced. Bristles are welded in their holders by friction melting, through relatively spinning the elements. The successive steps are aligning the bristles in tufts, forcing the ends of the bristles into the holders and spinning the holders or tufts to create frictional heat, thereby melting the interior of the holders and ends of the bristles, flowing the two elements together and welding them.

Alternatively, the holders may be molded about the bristles, or the bristles and plug may be heated and fused. Bonding is another method available for joining plugs and bristles. Since in a preferable form materials of the plugs and bristles are similar, the bonding material will have the same effect upon all elements of the joint.

The bristle holders or plugs may take any form, for example, cylindrical, rectangular or elliptical, providing that the mounting strips are configured to receive the plugs. Although bristles usually extend perpendicularly from mounting strips, some bristles, notably end tufts may be disposed angularly from the strips. The latter form is particularly useful with edge shoes, which conventionally are employed in rotary brushes.

As discussed in United States Patent No. 3,228,053, tufts of bristles may be mounted in metallic strips, and the strips may he slid into permanent cores of rotary sweeping machines, so that worn brush sections may be replaced. In order that the replaceable strips wear before the core, the strips usually are made of aluminum. While 0 manufacturing the strips, it is convenient and desirable to extrude perpendicular collars about holes which are punched in the strips to receive bristle tufts. As part of the subject matter of that patent, damper collars are added between the aluminum collars and the bristles. These damper collars fulfill their purpose by being resilient and by extending outward from the collars in order to curve wire bristles and to prevent their failure by fatigue from bending adjacent the collars.

It is extremely important in the present invention that bristles be held tightly within the collars to prevent hammering and wearing away of the aluminum. If free play were permitted, impact of the bristles would enlarge the collars and would wear away the holders, which further would result in increased momentums and impacts, which finally would destroy the apparatus or at least would destroy the effectiveness of the brush. In a preferable form of the present invention, plugs in which bristles are mounted are relatively rigid. The plugs have an outside throat diameter slightly larger than the inner diameter of the collars of the mounting strips. The plugs are forced through the strips, and the aluminum collars are forced open within the limits of their elasticity. The aluminum collars, elastically seeking to contract, firmly hold the plugs in place. The hoop strength of the aluminum collars is so great that, once inserted, the plugs are held fast through the life of the brush. Known elastomeric damper collars, which are made of rubber or of neoprene, have been made identical in size or smaller than the metal collars in which the damper collars fit. Consequently, the elastomeric collars do not enlarge the metallic collars within their elastic limits. Therefore, previously known damper collars do not take advantage of the elasticity and hoop strength of the collars.

Aluminum mounting strips have been tested and have been found to possess good operational characteristics. Mounting strips may be made of other materials which are economical and which are readily deformable; carbon steel and plastics are suitable.

As disclosed herein, mounting strips may be made of material similar to the bristles, and mounting strips and plugs may be manufactured integrally. In the latter case, groups or tufts of bristles are inserted in the plugs, and the bristles are spun to create sufficient heat to cause mutual flowing of the plugs and bristles, which produces welded joints. Variations in strength, resiliency and hardness of the materials may be controlled conventionally by adding pigments to the raw materials. Made in but a single form, plastic strips may be mounted longitudinally in keyways as shown in FIGURE 6, or the strips may be circularly bent as shown in FIGURE to fit rotary brushes made up of adjacent circular elements. The latter form has an advantage of providing universal refills for brushes of uniform diameter and of varying lengths.

One objective of this invention is the providing of improved tufts of bristles for street sweeping machines.

This invention has as another important purpose, the providing of improved bristle mountings for brushes.

This invention has as another objective, the provision of novel brush assemblies.

Another important purpose of this invention is the provision of novel mounting strips and tuft assemblies.

This invention has as a further objective, the provision of methods for joining bristles and holders.

Further objectives of this invention will be apparent from the specification and from the drawings in which:

FIGURE 1 is a perspective view of a rotary street sweeper of a type described herein;

FIGURE 2 is a perspective view of bristles assembled in a plug;

FIGURE 3 is a perspective view of a mounting strip in which a tuft of bristles has been mounted, and from which a section has been removed to reveal details of the punched holes and extruded collars;

FIGURE 4 is a perspective view of a mounting strip having integrally formed bristle holding means;

FIGURE 5 is a side elevation detailing one form of suggested use for the integrally formed mounting strip shown in FIGURE 4;

FIGURE 6 is an end elevation of a mounting strip core mounting device which may be bolted or otherwise fixed on the core or drum of a cylindrical brush;

FIGURE 7 is a schematic detail of steps in an assembly process for securing bristles in holding means or plugs;

FIGURE 8 is an alternate form of the assembly process.

Referring to the drawings, FIGURE 1 reveals one type of runway and street cleaning rotary brushes discussed herein. Pickup brush 1 sweeps dirt into hopper 2; the process conventionally employs conveyors to lift dirt and sweepings into the hopper. Extremely beneficial to the sweeping process is the flicking or snapping of the ends of bristles as they leave the ground. The preferred oriented polypropylene bristles disclosed herein have suflicient resiliency and strength and tendency to remain in tufts to provide good flicking or snapping characteristics.

A bristle mounting means of plug 30, as illustrated in FIGURE 2, has a throat 32 and a cap 34. A circular opening at the base of throat 32 reveals a hollow cylindrical wall which receives a tuft of bristles 10. Ends 12 of bristles 10 are forced into cylindrical opening 32 in plug 30, and the bristles are clamped while plug 30 is spun, creating frictional heat, melting and fusing the materials, and welding bristles 10 to plug 30, as shown in FIGURE 7. Alternatively, the plugs may be clamped, and the tufts may be spun.

In FIGURE 3, aluminum tuft mounting strip 40 is cut away to illustrate the formation of tuft mounting holes and collars which are made with an internal diameter equal to or slightly less than the outer diameter of plug throat 32, to ensure a tight fit. Differences in the diameters are held within the elastic limit of aluminum so that when collar 44 is stretched upon the insertion of throat 32, the aluminum annulus is expanded elastically. The hoop strength of collar 44 is brought to bear in its contraction, effecting a tight hold on throat 32. The throat must be larger than the collar, or at least must be the same size to prevent hammering of bristles 10 and plug 30 against the aluminum collar 44.

FIGURE 4 illustrates another embodiment of the invention in which bristle holders or plugs 50 and mounting strip 60 are constructed as an integral piece. Friction welding of bristles 10 in plugs 50 may be accomplished by clamping mounting strip 60, forcing tufts of bristles 10 into plugs 50, and spinning the tufts to create heat and fuse the materials, as shown in FIGURE 7. Polypropylene strips 60 may be attached to rotary brush cores of varying length by bending strips 60 into circular sections 70 as shown in FIGURE 5. If variations in hardness and resiliency are desired between the strips, plugs, and bristles, plastic compositions may be varied.

Strips 40 having tufts of bristles 10 mounted therein may be held on the core of a cylindrical brush assembly 1 by a plurality of mounting channels 80, as illustrated in FIGURE 6. Central ridges 82 of channels are fastened to the brush core with fasteners 90. Lobes 84 of channel 80 hold strip 40 firmly in place. Although this invention has been described with specif- 1c embodiments, many modifications and variations will be obvious to those skilled in the art. The invention is not limited to the disclosed examples; rather, the limits of the invention are precisely defined only in the following claims.

What is claimed is:

1. Rotary brush apparatus comprising a brush base mounted for rotation on a vehicle; a plurality of bristletuft elongated mounting strips having first and second opposite sides mounted on said base with the second sides facing the base, said strips defining a plurality of apertures aligned longitudinally in said strips, said strips further comprising right oriented collars integrally extending from first sides of the strips and surrounding the apertures; a plurality of bristle holders mounted in the strips, said bristle holders defining integral throat and cap portions, said throat portions defining central bristle receiving recesses and being forcefully positioned within the apertures and collars of the mounting strips, external dimensions of the throat portions being slightly greater than corresponding internal dimensions of the apertures and collars of the mounting strips, whereby residual opposing stresses remain in said throat portions and in said apertures and collars, said cap portions overlying areas of said second sides of said strips adjacent the apertures, and a plurality of bristles anchored within said holders.

2. Rotary brush apparatus of claim 1 wherein said bristles comprise hairpin bristles having bends tightly wedged within the holders.

3. Rotary brush apparatus of claim 1 wherein said bristles are tightly welded within the holders.

4. Rotary brush apparatus of claim 1 wherein the elongated mounting strips and integral collars are aluminum.

5. Rotary brush apparatus comprising a brush base mounted for rotation on a vehicle, a plurality of bristletuft elongated mounting strips having first and second opposite sides mounted on said base with the second sides facing the base, said strips defining apertures aligned longitudinally in said strips, said strips further comprising right oriented collars extending from the first sides of the strips and surrounding the apertures and a plurality of bristle tufts welded in the collars and apertures.

6. Rotary brush apparatus comprising a brush base mounted for rotation on a vehicle; a plurality of bristle tuft elongated aluminum mounting strips having first and second opposite fiat sides mounted on said base with said second side facing said base, said strips defining a plurality of stamped apertures aligned longitudinally in said strips, said strips further comprising a plurality of integral extruded right oriented collars surrounding the apertures on the first side of said strips; a plurality of thermoplastic bristle holders mounted in the strips, said holders comprising integral cap and throat portions, said throat portion defining bristle receiving recesses extending from walls of said throat portions opposite said cap portions to said cap portions, said throat portions being forcefully positioned within the apertures and collars of said strips, external dimensions of the throat portions being slightly greater than corresponding internal diameters of the apertures and collars, and the cap portions overlying areas of the second sides of the strips adjacent the apertures, whereby opposing stresses remain in the holders and in the apertures and collars; and a plurality of like thermoplastic bristles disposed in the recesses of the holders and Welded to the holders, thermoplastic material of the holders and bristles being interspersed.

7. Rotary brush apparatus comprising elements which are a cylindrical bristle holder having a cap and throat, and a tuft of bristles inserted in the throat, wherein said elements comprise like materials, and wherein each of said elements is fused into the other.

References Cited UNITED STATES PATENTS 347,048 8/1886 Kane 15-191 846,003 3/1907 Brantley 15-190 X 2,672,640 3/1954 Peterson 61; a1 15160 2,878,069 3/1959 Wessel 15-192 X 3,029,456 4/ 1962 Pharo 15-480 3,216,038 11/1965 Gould et al. 15--159.1 3,228,053 1/1966 Horton et a1 15-183 FOREIGN PATENTS 348,750 5/1937 Italy.

CHARLES A. WILLMUTH, Primary Examiner. P. FELDMAN, Assistant Examiner.