Brushing – scrubbing – and general cleaning – Implements – Brush or broom
Reexamination Certificate
1997-12-31
2001-01-16
Graham, Gary K. (Department: 1744)
Brushing, scrubbing, and general cleaning
Implements
Brush or broom
C015S179000, C451S508000, C451S521000
Reexamination Certificate
active
06173470
ABSTRACT:
TECHNICAL FIELD OF THE INVENTION
This invention relates to the field of rotatable tools of the type having projecting bristles such as wire brushes intended for surface cleaning and to some extent shaping purposes, optionally also having manufactured edges or teeth, for shaping and forming materials. In particular this invention relates to brushes characterized by the way—and positions—at which the bristles are fixed or joined in or on the brush body or carrier and the shape of the carrier.
BACKGROUND
Grinders such angle grinders equipped with wire brush-like spinning attachments are widely used in trade for the removal of paint, rust, and other coatings from engineering structures, vehicles, ships, and the like. Wire brush attachments have some disadvantages, such as providing a greater torque on the spinning angle grinder than the torque from an abrasive disk. The tools described in this specification are developments of tools suitable for use with grinders as described in our earlier patent applications such as PCT/NZ95/00035 and PCT/US96/16511, the contents of which are incorporated by way of reference. The tools described therein provide advantages over prior-art tools, the advantages including better control of the “bite” by varying the angle of attack; the tool having a non-cutting rest surface (which may spin), also visibility of the work surface at or about the cutting edge, and forced cooling of the work surface.
STATEMENT OF THE INVENTION
The invention comprises an accessory for a grinder comprising a rotatable disc-shaped tool having a first surface and a second surface, an axis of rotation and being adapted to be mounted on an arbor of an angle grinder and being provided with a working zone extending inwardly from the perimeter of the tool; and the working zone of the rotatable tool is provided with a plurality of brush-like bristles, wherein the bristles are mounted to project outwards from a surface in two or more spaced-apart groups around the working zone, and the edge of the disc in the portions of the disc between the groups is modified by removal of segments of the body of the disc. In use the work surface experiences an intermittent cutting or abrading action interspersed with non-abrading or non-cutting periods the spaced-apart groups being capable in use of aiding the movement of air about the working surface. In addition the removal of segments of the disc periphery aids in viewing the surface of a workpiece being abraded as the disc rotates.
The invention also comprises an abrasive tool provided with brush-like bristles which has a cup-shaped support with the bristles projecting in at least two spaced groups from around the rim of the cup.
Preferably the bristles are formed from metallic wire or the like, although optionally they may be made of some other substance such as hair, plastics, or the like. Also preferably the bristles are mounted in at least three spaced-apart groups. In some cases the bristles can be mounted in groups having a spiraling arrangement on the surface of a disc-shaped accessory, capable in use of aiding the movement of air over the surface of the accessory.
The tool is adapted for mounting upon the spindle or arbor of an angle grinder tool and for this purpose it is preferably provided with an optionally threaded central mounting aperture. The accessory may be a flat disc, or it may be a disc that is curved in cross-section like a saucer (and generally be used with the convex surface against the work), or it may have a deep, cup-like cross-section with the bristles extending substantially from the edge of the cup—and is used with the concave side toward the work.
In a preferred embodiment of the invention the tool is provided with a rest means having less effective abrading or cutting properties, located in fixed relation to the working zone of the tool and displaced from the working zone along the line of the axis of rotation of the tool and away from the grinder, so that in use an operator can rest the less effective rest means of the tool upon the work surface and then tilt the grinder about the tool so varying the angle of attack and thereby either increase or decrease the amount by which the working zone is impressed upon the work surface.
The working zone comprises a plurality of bristles capable of performing a cutting or abrading action when in rotational motion, the bristles projecting from the accessory in the working zone and the length of the bristles being such that at least a portion of the rest means can be contacted with a work surface with substantially no contact occurring between the bristles and the work surface. Preferably the bristles are located in a working zone which extends from the outer perimeter of the disk-shaped tool to a point that is up to two thirds, and more preferably up to one third, of the distance from the perimeter to the axis of rotation.
The tool preferably has a convex surface with the working zone provided by an outer peripheral portion of the convex surface of the disk having groups of bristles located thereon and in which the rest means is provided by a portion of the convex surface of the disc located radially inward of the working zone. However the rest means can be provided by an inner rest zone or protrusion that is not part of the disc such as a separately rotatable protrusion mounted by means of a bearing onto the tool or grinder spindle or a central protrusion built out from the body of the tool. Where the disc has a deep cup shape with the bristles projecting from the rim of the cup the rest means can be provided by a projection within the cup extending beyond the rim thereof. In use the bristles are moved outwardly by centrifugal force and by contact with the workpiece such that the rest means allows an abrasive contact of the bristles with the workpiece that is less effective than when the tool is rocked about the rest means to increase the pressure of contact between the bristles and the workpiece surface.
The tool is preferably provided with at least one aperture surrounded by the material of the disk between its first surface and its second surface, capable, when the tool is rotating, of admitting light so that a view of the work surface may be obtained, and of assisting in the admission of air into the region beneath the tool then over the work surface.
The segments of the body of the disc that are removed between the groups of bristles can have the form of chords removed from the periphery of the disc or alternatively they may be apertures open towards the periphery of the disk and forming a throat or an inwards digression of the edge of the disk. Optionally the or each such aperture can be formed with at least one edge of a substantially hard material thereby forming a cutting edge.
DESCRIPTION OF PREFERRED EMBODIMENTS
In the following passage a number of modified wire brushes that include one or more of the principles of the present invention. These are of course a set of non-limiting examples or preferred embodiments of the invention, and do not specify all possible variations.
REFERENCES:
patent: 1497921 (1924-06-01), Levedahl
patent: 1564226 (1925-12-01), Finnel
patent: 1606821 (1926-11-01), Anderson
patent: 2153207 (1939-04-01), Petty
patent: 2480877 (1949-09-01), Peterson
patent: 2930056 (1960-03-01), Lappin
patent: 4771498 (1988-09-01), Torta
patent: 21648 (1978-02-01), None
Bennett David
Graham Gary K.
Norton Company
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