Corner grout cutter guide

An apparatus and method are provided for guiding the bit of a rotary hand tool along a corner of a work surface formed by two or more abutting surfaces, through use of a corner cutting apparatus which includes a corner cutting guide having a housing, defining an axis of the housing, and adapted for attachment of the rotary tool with the axis of the rotary tool extending through the housing along the axis of the housing. The housing also includes first and second guide walls, for engaging abutting walls at a corner of the work surface. The first and second guide walls are disposed substantially perpendicular to one another, and have respective outer surfaces which, if projected, would intersect to form a line lying in a common plane with the axis of the housing and oriented at an acute angle to the axis of the housing.

FIELD OF THE INVENTION

This invention relates to rotary hand tools, and more particularly to a corner cutting apparatus having removable corner cutting guide attachment apparatus for use with a rotary tool, that allows a bit of the rotary tool to be accurately guided along a corner for performing tasks such as removing grout from a corner of a tiled wall or floor.

BACKGROUND OF THE INVENTION

It is known to use a rotary hand tool for removing grout between tiles, and for providing a guide attachment to facilitate guiding the bit of the tool along grout lines on flat surfaces. U.S. Pat. No. 6,244,796, to Schuebel, discloses such a device.

Prior guide attachments, such as those disclosed by Schuebel, are configured only for use on flat surfaces, however, and cannot be used for removing grout from a corner. It is desirable to provide an apparatus and method for guiding a rotary hand tool along a corner of a work surface, during tasks such as removing grout from a corner joint formed by tiles on abutting walls of the work surface.

BRIEF SUMMARY OF THE INVENTION

The invention provides an improved apparatus and method for guiding the bit of a rotary hand tool along a corner of a work surface, through use of a corner cutting guide. The corner cutting guide may be configured for guiding the bit into a corner of the work surface formed by three abutting planar surfaces, such as might be encountered at the common juncture of two walls with a floor or a ceiling.

In one form of the invention, a corner cutting guide is provided for a rotary hand tool that includes an outer enclosure and a collet that is rotatable about an axis of the rotary tool and adapted for receiving a bit for engaging a work surface. The corner cutting guide includes a housing, defining an axis of the housing, and adapted for attachment of the rotary tool with the axis of the rotary tool extending through the housing along the axis of the housing. The housing also includes first and second guide walls, for engaging abutting walls at a corner of the work surface. The first and second guide walls of the housing are disposed substantially perpendicular to one another, and have respective outer surfaces which, if they were projected, would intersect to form a line lying in a common plane with the axis of the housing and oriented at an acute angle to the axis of the housing. A forwardmost surface of the corner cutting guide may be configured so that it does not extend forward of an intersection formed by the axis of the housing and the line formed by the intersections of the projected outer surfaces of the first and second guide walls of the housing.

The included angle formed by the outer surfaces of the guide walls may be bisected by the common plane including the axis of the housing and the line formed by the intersection of the outer surfaces of the guide walls of the housing. The outer surfaces of the guide walls may be perpendicular to one another, or disposed at some other angle with respect to one another. The included angle formed by the outer surfaces of the guide walls may also be slightly less than perpendicular. The intersection of the guide wall outer surfaces may also be blunted along a portion of the intersection.

In another form of the invention, a corner cutting apparatus includes a rotary hand tool including a corner cutting guide, according to the invention.

Other aspects, objectives and advantages of the invention will be apparent from the following detailed description and the accompanying drawings.

DETAILED DESCRIPTION OF THE INVENTION

FIGS. 1–11show an exemplary embodiment of a corner cutting apparatus10, and a corner cutting guide12, according to the invention. Referring toFIG. 11, the corner cutting apparatus10includes a rotary hand tool14and the corner cutting guide12.

In the exemplary embodiment of the corner cutting apparatus10, the corner cutting guide12takes the form of a corner grout cutter guide, as shown in the drawings that can be releasably mounted to the rotary tool14. In the exemplary embodiment, the rotary tool14is shown in a well known form of a typical, so called, Dremelt® rotary tool.

Such rotary tools14typically comprise a chuck or collet16that drives a rotary bit18. In the exemplary embodiment, the rotary hand tool14also includes threading20at one end of an outer enclosure22, or handle, of the rotary tool14, that is adapted to connect the rotary tool14to cutter guides, such as the corner grout cutter guide12of the exemplary embodiment.

Referring the drawings generally, the exemplary embodiment of the corner grout cutter guide12includes a housing24and a plastic molded mounting sleeve26. As shown inFIGS. 8 and 10, the housing24of the exemplary embodiment is formed from two parts, an outer shell23of molded plastic, which defines a central cylindrical opening28of the housing, and a clear plastic insert25that is inserted into a lower end of the central cylindrical opening28in the housing24, and locked in place by a spring catch. The insert25defines a hole27, for passage of the bit18through the insert25. The sleeve26is slidably mounted in the upper end of the central cylindrical opening28of the housing24to provide for linear depth adjustment of the bit18.

The corner cutting guide12also includes a thumb screw30can be tightened and loosened to thereby act as a clamp for releasably securing the mounting sleeve26to the housing24of the corner cutting guide12at desired depths. A nut32, supported in a groove34of the housing24, secures the thumb screw30.

The mounting sleeve26includes a threaded hole36that is adapted to receive the threads20of the outer enclosure22of the rotary tool14, as shown inFIG. 11. The central opening28in the housing24and the threaded hole36in the sleeve26, in combination with the hole27in the insert25, form a central through hole that extends through the entire corner cutting guide12, for allowing the bit18of the rotary tool14to contact the desired working surface in a corner formed by two or more abutting walls of the work surface. The housing24is configured to position the surface engaging bit18into corners, and can be used for such tasks as engaging, cleaning and/or removing grout from such corners.

As shown inFIGS. 3–5, the housing24of the corner cutting guide12includes a pair of guide walls38,40that are oriented approximately perpendicular to one another, and more preferably slightly less than perpendicular to one another, which are adapted to slide against generally perpendicular wall surfaces which define a corner to be worked. By being slightly less than perpendicular, the guide walls38,40of the housing24more easily fit into tight corners and better accommodate situations where walls are not perfectly perpendicular or have shifted over time.

As shown inFIG. 11, the collet16of the rotary hand tool14is rotatable about an axis42of the rotary tool14. As shown inFIGS. 3,5, and9–11, the housing24of the corner cutting guide12also defines an axis44which, when the rotary tool14is installed in the corner cutting guide12, is nominally and essentially coincident with the axis42of the rotary hand tool14. The housing24is adapted, by virtue of the threaded hole36in the sleeve26, for attachment of the rotary tool14with the axis42of the rotary tool14extending through the housing24along the axis44of the housing24.

As best seen inFIGS. 3–6, and8, the housing24also defines first and second guide walls38,40, which are adapted for engaging abutting walls at a corner of the work surface. As shown inFIG. 6, the first and second guide walls38,40of the housing24are disposed substantially perpendicular to one another, and have respective outer surfaces46,48thereof which, if projected, would intersect to form a line50, as shown inFIGS. 5 and 6, lying in a common plane52(as shown inFIG. 6) with the axis44of the housing24and oriented at an acute angle54to the axis44of the housing24.

As shown inFIG. 6, in the exemplary embodiment of the corner cutting guide12, the included angle56formed by the outer surfaces46,48of the guide walls38,40is bisected by the common plane52that includes the axis44of the housing24and the line50formed by the intersection of the projections of the outer surfaces46,48of the guide walls38,40of the housing24, but in other embodiments of the invention, the common plane52need not bisect the included angle56.

The outer surfaces46,48of the guide walls46,48of the housing24may be made perpendicular to one another, in some embodiments of the invention. In the exemplary embodiment of the corner cutting guide12, however, the included angle56formed by the outer surfaces46,48of the guide walls38,40is slightly less than perpendicular to allow the corner cutting guide12to fit into corners of walls that are less than perpendicular to one another.

As will also be noted, the housing24is blunted, as shown by surface58inFIGS. 2–4and8, to provide clearance between the corner cutting guide and irregularities in the corner of the work surface, such as a bead of grout to be removed or repaired. In the exemplary embodiment, the blunting is formed by a flat surface58, but other embodiments of the invention may use other forms of blunting, such as curved surfaces, concave surfaces, grooves, etc., to provide clearance for irregularities in the corner.

As shown inFIGS. 3–5and10, the housing24further defines a forwardmost surface60, thereof that does not extend forward of an intersection62formed by the axis44of the housing24and the line50formed by the intersections of the projected outer surfaces46,48of the first and second guide walls38,40of the housing24. As illustrated inFIG. 5, by virtue of having the housing24configured in this manner, a bit extending along the axis44of the housing24can be guided into a common corner formed by three walls, with the first and second guide walls38,40of the housing24abutting or closely adjacent to respective first and second walls of the corner, and the forwardmost surface60of the housing24abutting or closely adjacent to a third wall of the corner, as represented by line64inFIG. 5.

Those having skill in the art will also recognize that, although invention has been described herein with reference to several exemplary embodiments, many other embodiments of the invention are possible. For example, a corner cutting guide according to the invention, can be made from materials other than plastic, such as metal. The corner cutting guide, in a corner cutting apparatus, according to the invention, may also be incorporated integrally into the outer enclosure of a rotary tool of the corner cutting apparatus.