Power brush

Abstract

A power-brush apparatus has a housing and a brush rotatable on the housing about a brush axis and having bristles extending generally radially of the axis and having tips defining on rotation of the brush a circular orbit centered on the axis. The tips are engageable at a location with a workpiece surface. In accordance with the invention a blocking element is positioned radially inside the orbit immediately upstream from the location in a normal rotation direction of the brush. A drive rotates the brush in a working direction about the axis relative to-the housing at a predetermined angular speed in the direction and thereby orbits the tips of the bristles about the axis such that the bristles engage the blocking element, are slowed thereby, and when released thereby snap back to accelerate forward and strike the workpiece at an augmented speed.

Description

BRIEF DESCRIPTION OF THE DRAWING

The above and other objects, features, and advantages will become more readily apparent from the following description, reference being made to the accompanying drawing in which:

FIG. 1 is a perspective view of the power-brush apparatus according to the invention;

FIG. 2 is a largely schematic side view of the power brush;

FIG. 3 is another side view;

FIG. 4 is an exploded sectional end view of the brush assembly; and

FIG.. 4A is a large-scale view of the detail indicated at IVA in FIG. 4.

Claims

1. A power-brush apparatus comprising: a housing;a brush rotatable on the housing about a brush axis and having bristles extending generally radially of the axis and having tips defining on rotation of the brush a circular orbit centered on the axis, the tips being engageable at a location with a workpiece surface;a blocking element positioned radially inside the orbit immediately upstream from the location in a normal rotation direction of the brush; anddrive means for rotating the brush in a working direction about the axis relative to the housing at a predetermined angular speed in the direction and thereby orbiting the tips of the bristles about the axis such that the bristles engage the blocking element, are slowed thereby, and when released thereby snap back to engage the workpiece surface at a greater peripheral speed than the angular speed.

2. The power-brush apparatus defined in claim 1 wherein the blocking element is fixed on the housing.

3. The power-brush apparatus defined in claim 2 wherein the blocking element has a radial outermost edge generally lying on the orbit.

4. The power-brush apparatus defined in claim 1 wherein the blocking element is spaced at most 70° upstream in the direction from the location where the tips engage the workpiece.

5. The power-brush apparatus defined in claim 1 wherein the blocking element is spaced between 25° and 45° upstream in the direction from the location where the tips engage the workpiece.

6. The power-brush apparatus defined in claim 1 wherein the brush comprises a core sleeve from which the bristles extend.

7. The power-brush apparatus defined in claim 6, further comprising: a pair of axially spaced holder disks flanking the core sleeve, rotatable about the axis on the housing, and connected to the drive means.

8. The power-brush apparatus defined in claim 1 wherein the bristle tips are bent forward in the direction.

9. The power-brush apparatus defined in claim 1 wherein the bristles are provided at density of at most 16 bristles per cm2.

10. A method of abrading a workpiece, the method comprising the steps of: rotating a brush on a housing about an axis in a direction at a predetermined angular speed such that tips of bristles extending generally radially of the axis define a circular orbit centered on the axis;engaging the tips radially at a location with a workpiece surface to abrade the surface at the location; andpositioning a blocking element radially inside the orbit immediately upstream from the location in the direction and thereby temporarily slowing angular movement of the bristle tips such that when released they snap back to engage the workpiece surface at a greater peripheral speed than the angular speed.