Handheld power tools are used for many applications. For instance, they can be used to cut a workpiece. Cutting a workpiece can include cutting across the surface of a generally planar workpiece, cutting off an end of a length of workpiece, and so forth. Workpieces may comprise materials such as wood, metal, plastic, glass, and so forth.
Handheld power tools can also be used to grind a workpiece. Grinding involves the removal of material from a workpiece surface by abrasion. Grinding a workpiece can produce smooth or fine surface finishes. Another application of grinding includes producing channels, slots, and grooves in a surface of a workpiece.
A prior art angle grinder is one example of a handheld power tool that is used for cutting and grinding. An angle grinder includes an abrasive rotatable implement rotatably mounted to a powerhead assembly at the end of a motive source. The housing of the motive source often serves as a handle. Typically, the abrasive rotatable implement is coupled to a gearbox and driven by an electric motor, AC or DC, or compressed air. Electric motors can be supplied with electric energy via either an external power source or a battery, such as a rechargeable battery.
In typical prior art angle grinders, the abrasive rotatable implement is offset from a longitudinal axis of the motive source and/or set at an angle to a longitudinal axis of the motive source. The axis of rotation of the implement does not intersect the longitudinal axis. The offset can disadvantageously limit the inherent stability of an angle grinder and, as a result, its functionality. For example, the offset and/or angle of the abrasive rotatable implement makes cutting or grinding along a straight line unstable. Further, the offset and/or angle of the abrasive rotatable implement makes aligning the rotatable implement with an intended location of a cut, cutoff, or grinding area difficult. Thus, the accuracy and precision of machining a workpiece can be diminished by an abrasive rotatable implement that is offset or angled. Additionally, offset grinders are generally bulky and hard to maneuver in smaller confined spaces.
The following U.S. Patent and U.S. Patent Publication references provide examples of grinding tools and are expressly incorporated herein by reference for all purposes: U.S. Pat. Nos. D330496, D333766, 5,384,985, 6,669,542, 6,860,260, 6,981,907, 6,386,961, 7,0145,48, and 2006/0276114.