Cutlery – Cutting tools – Saw
Reexamination Certificate
2001-11-13
2004-04-20
Watts, Douglas D. (Department: 3724)
Cutlery
Cutting tools
Saw
C125S013030
Reexamination Certificate
active
06722047
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention generally relates to attachments for rotary hand tools and more particularly to a tool guard attachment for a flat circular tool implement that is to be used in connection with a powered rotary hand tool.
Small rotary hand tools have been marketed for many years for use in carrying out woodworking and metal working tasks by hobbyists as well as commercial artisans. Such small rotary hand tools generally have a motor unit with a rotary output shaft that extends from a nose portion of the tool housing. The output shaft typically includes an attachment mechanism for attaching various kinds of tool bits or implements such can be used to perform such tasks as grinding, carving, sawing, sanding and polishing, for example.
Various types of attachments are also currently available for use with rotary hand tools (such as those marketed under the Dremel brand made by the S-B Power Tool Company of Chicago, Ill.) to aid the user in performing specialized tasks more accurately or more efficiently. Such attachments include various guide attachments for controlling the tool while performing various tasks that relate to woodworking or other hobbies, as well as various commercial activities. Such attachments often significantly improve the accuracy and effectiveness of tool implements that are available for use in such rotary hand tools.
SUMMARY OF THE INVENTION
The present invention is a tool guard attachment for attachment to a rotary hand tool of the type which has a housing with a nose portion from which an output shaft protrudes and which typically has a mechanism for holding tool bits or implements. The tool guard attachment, which mounts to the nose portion of the rotary hand tool, has a guard housing with an enlarged guard portion at the outer end thereof which provides a shield or guard for a flat circular tool implement, preferably a saw blade, that is mounted on an arbor shaft assembly that in turn is connected by a U-joint to a drive shaft assembly at an acute angle relative to the arbor shaft assembly. The drive shaft assembly engages a driver nut or the like that is mounted to the output shaft of the rotary hand tool. The angle between the drive shaft and the arbor shaft is offset about 10 to 30° so that the rotary hand tool itself does not interfere with the cutting blade engaging a work surface at a perpendicular angle during operation. A lower guard that is retractable in the enlarged guard portion of the housing is normally biased away from the enlarged guard portion for protecting a user from injury. When a user positions the tool guard attachment for cutting, the user merely needs to press the attachment into contact with the work surface and the lower guard will retract into the enlarged guard portion and enable the saw blade to engage and penetrate into the work surface.
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Baber Brad M.
Ennis Ed
Hirschburger Wolfgang
Greer Burns & Crain Ltd.
S-B Power Tool Company
Watts Douglas D.
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