Abrasive coated fluted bit with recesses

#This invention relates to the field of hand held rotary tools and related accessories.

#Hand held rotary tools are widely used by many people, including craftspeople, homeowners, and artists. These rotary tools typically include an outer housing designed to be easily held within a human hand. The housing retains an electric motor which is operable to drive a rotatable chuck of the rotary tool. An accessory may be releasably secured to the chuck thereby enabling the rotary tool to rotatably drive the accessory.

#The widespread use of hand held rotary tools is a result, in part, of the wide variety of accessories that may be used with the tools. The accessories include cut-off wheels, polishing wheels, grinding wheels, sanding discs and other cutting bits. In addition to the availability of specialized types of shaping accessories, shaping accessories may further be specifically designed for the particular type of material that is to be shaped. For example, U.S. Pat. No. 6,758,639 assigned to Credo Technology Corporation discloses a bit that is designed for use with drywall.

#FIG. 1 shows a partial perspective view of a hand held rotary tool holding a bit with an interrupted leading edge including an abrasive layer in accordance with principles of the present invention;

#FIG. 2 shows a perspective view of the bit of FIG. 1;

#FIG. 3 shows a cross-sectional view of the bit of FIG. 1 showing multiple flutes on the bit in accordance with principles of the present invention;

#For the purposes of promoting an understanding of the principles of the invention, reference will now be made to the embodiments illustrated in the drawings and described in the following written specification. It is understood that no limitation to the scope of the invention is thereby intended. It is further understood that the present invention includes any alterations and modifications to the illustrated embodiments and includes further applications of the principles of the invention as would normally occur to one skilled in the art to which this invention pertains.

#FIG. 1 shows a partial perspective view of a hand held rotary tool 100. The rotary tool 100 includes a motor (not shown) for providing rotational movement to a chuck 102. A bit 104 is releasably coupled to the chuck 102. Operation of the motor in the rotary tool 100 rotates the chuck 102 which in turn rotates the bit 104.

#As shown in FIG. 2, the bit 104 includes a tool-engaging portion 106 that is configured for being gripped within the chuck 102 of the rotary tool 100. The opposite end of the bit 104 is a work section 108. The work section 108 includes two flutes 110 and 112 seen most clearly in FIG. 3 which is a cross-sectional view of the bit 104 taken along the line A-A of FIG. 1. The flutes 110 and 112 extend helically about the bit 104 in a clockwise direction from the end 114 of the working section 108 towards the tool-engaging portion 106. The flutes 110 and 112 terminate at the leading edges 116 and 118. The leading edges 116 and 118 are defined by the flutes 110 and 112 on one side and the lands 120 and 122, respectively, on the opposite side. In alternative embodiments, a single flute or more than two flutes may be used, such flutes extending in either a clockwise or counter-clockwise direction about the bit.