Abrading – Frame or mount – Portable abrader
Reexamination Certificate
1998-05-20
2001-06-12
Rose, Robert A. (Department: 3723)
Abrading
Frame or mount
Portable abrader
C015S141200
Reexamination Certificate
active
06244947
ABSTRACT:
TECHNICAL FIELD OF THE INVENTION
This invention relates to the field of disc-shaped rotating abrading tools of the type having manufactured surfaces for abrading and forming materials, and in particular this invention relates to a wire brush accessory which is adapted for use with a hand-held angle grinder.
BACKGROUND
A number of applications in the construction or repair of solid articles involve the selective removal of material from a bulk in order to produce a desired conformation or shape. For example a builder may remove some wood from a beam in order to produce a neat fit—more likely if the house being built is non-rectangular; a foundry removes surplus metal from sprues or joints between mould parts when producing a casting; a wood carver selectively removes wood in order to produce a carving; a panel beater frequently removes surplus plastic filler which was placed within a defect in an automotive panel to build it up, so that the outline conforms with the original outline of the panel; or a boat builder may have to remove kilograms of material, such as lead-filled fibreglass when shaping or repairing a hull.
The act of selective removal, particularly if carried out by abrasive means, involves the expenditure of considerable effort and abrasive materials. The work can be quite slow. There is also a number of problems and health risks associated with the consequent fine dust, having potentially toxic, carcinogenic, or explosive properties. Moreover, dust containing glass fibre is particularly dangerous to the lungs.
One form of tool used for removal of loosely adhered material is a cup-shaped wire brush rotating on a spindle. One such device is described in German OLS 25 02 698.
STATEMENT OF THE INVENTION
In a previous Application published as WO 95/29788 on Nov. 9, 1995, Applicant described an invention in which a first aspect comprised an accessory for a grinder including a rotatable tool having a shape substantially that of a disk, having an axis of rotation and capable of being mounted on an arbor of an angle grinder, characterised in that the rotatable tool is provided with at least one working zone within an active zone extending inwardly from the perimeter of the tool; and rest means extending substantially inwardly from the working zone of the tool, which rest means is displaced from the working zone along the line of the axis of rotation. In some cases the working zone is co-extensive with the active zone.
In a related aspect the previous Aplication comprises an accessory for a grinder characterised in that the rest means is concentric with and supported on the rotatable tool.
In a related aspect the previous Application comprises an accessory for a grinder characterised in that the rest means comprises a portion of a convex working surface of the rotatable tool and the rest means includes at least one rubbing surface located between the active zone and the axis of rotation.
In a related aspect the previous Application comprises an accessory for a grinder characterised in that the rest means comprises a fixed rubbing surface or nose supported on the angle grinder and displaced so as to be supported beyond the rotatable tool. (By “beyond” we mean beyond the end of the arbor, or below the tool as it is normally held).
In a further related aspect the previous Application comprises an accessory for a grinder comprising a rotable tool characterised in that the working zone comprises at least one area within the active zone of the rotatable tool, and the active zone surface extends radially inward over the working surface from the perimeter for up to two thirds and preferably one third of the radius of the rotatable tool.
The present invention provides a further extension of the general concepts embodied in the previous Application described above. In one aspect of this extension the invention provides an accessory for a grinder comprising a rotatable disk-shaped tool, having an axis of rotation and adapted to be mounted on an arbor of an angle grinder, the accessory being provided with a working zone located on the rotatable disk-shaped tool and extending inwardly from the perimeter of the tool; and rest means extending substantially inwardly from the working zone of the tool, which rest means is located radially inward from the working zone and displaced by a fixed distance along the line of the axis of rotation of the tool and away from the grinder, wherein the working zone of the rotatable tool is provided with a plurality of stiff bristles capable of performing a cutting or abrading action when in rotational motion, the bristles projecting from the surface of the working zone and the length of the bristles being such that a portion of the rest means can be contacted with a work surface without contact occurring between the bristles and the work surface.
In a preferred aspect of the invention at least one viewing aperture is provided through the disk of the rotatable tool and at least one viewing aperture may, when the tool is rotating, also serve to cause air movement.
Preferably the grinder has a central recessed mounting aperture provided with gripping means or clutch means capable of disengagement substantially as long as a torque applied between the rotatable spindle and the tool exceeds a predetermined amount and optionally a resilient mounting means capable of reducing vibration.
In use the preferred disk-shaped rotatable abrading tool is mounted on a rotatable spindle, and comprises an active zone on said rotatable abrading tool, which active zone comprises a least one working zone comprising stiff bristles capable of removing material from the work surface, and rest means (a rest zone) dispaced along the axis of rotation by a fixed amount from the working zone, which rest means, in use, permits control of the shaping action of the grinder system by first contacting the rest means with the work surface and then tilting the grinder system to cause or increase engagement of the bristles in the working zone with the work surface.
In a further preferred aspect the invention the rest means comprises a rubbing surface provided with rotational bearing means, which preferably moves on the same axis as the disk-shaped tool, so that in use the rubbing surface may rotate independently of the rotatable tool.
Preferably at least one viewing aperture is provided through the tool and in which at least one viewing aperture may when the tool is rotating also serve as to cause air movement.
The rotatable abrading tool of the invention preferably has a central mounting aperture adapted for attachment to a rotatable spindle.
Preferably the rotatable tool has a central recessed mounting aperture adapted for attachment to a rotatable spindle and is provided with clutch means capable of disengagement while a torque applied between the rotatable spindle and the tool exceeds a predetermined amount.
Preferably the central recessed mounting aperture is also provided with resilient mounting means capable of reducing vibration caused by eccentricity.
Preferably the means for attachment of the tool comprises a shaped depression, shaped to match the profile of an arbor and nut. Preferably the nut includes means to impose a grip on the tool using static friction, and preferably the static friction is overcome at a torque less than that which can damage a means for driving the rotary shaft. Preferably the tool is adapted for use with an ordinary angle grinder. Optionally it may be adapted for use with other rotatable powered machines. Optionally the angle grinder may be fitted with a guard, in order to control swarf.
In use the tool of the invention provides a method for shaping material, comprising the steps of (a) causing a tool according to the above description having viewing apertures therein to be affixed to an angle grinder or the like, (b) applying power to the angle grinder motor, (c) holding the tool against the work while tilted at a low angle to it (so that the rest means contacts the surface but the working surface is not engaged) and raising the tilt to a higher angle so
Bennett David
Norton Company
Rose Robert A.
LandOfFree
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