Cutting by use of rotating axially moving tool – With work-engaging structure other than tool or tool-support – Frictionally engaging sides of opening in work
Reexamination Certificate
1999-06-14
2001-10-09
Bishop, Steven C. (Department: 3722)
Cutting by use of rotating axially moving tool
With work-engaging structure other than tool or tool-support
Frictionally engaging sides of opening in work
C408S057000, C408S705000
Reexamination Certificate
active
06299391
ABSTRACT:
TECHNICAL FIELD
The subject invention relates generally to a boring tool that is typically used to bore deep holes and more particularly to a boring tool assembly that has guides to aid in assuring that the boring tool continues to bore in a straight line even when the outer diameter of the cutting tool reduces in size due to wear or re-sharpening.
BACKGROUND ART
Boring tools are well known in the art. Many of these known boring tools have a cutting tool disposed on one end thereof for boring a hole in a material, such as steel, aluminum or cast iron. In long bored holes, the boring tool has a tendency to “wander” as opposed to cutting in a straight line. This may be attributed to the material being cut varying in toughness or hardness causing the boring tool to take the path of least resistance. Many times the hole to be bored has been partially defined by the casting or forging process to form a cored hole. These cored holes are not always disposed in the proper location or there are interrupted surfaces that the cutting tool must cut. In these situations, the cutting tool may “wander” and not cut in a straight line, especially if the boring bar is long. In order to offset this “wandering” of the cutting tool, it is known to provide a pilot stem on the forward end of the boring tool that is positioned in a pilot hole. With the pilot stem in the pilot hole, the cutting tool is maintained in its proper location. This type of tool requires boring a pilot bore hole first to receive the pilot stem. Additionally, it is known to provide separate bearing assemblies that are mounted on the boring tool behind the cutting tool. This also works to keep the cutting tool aligned properly. These bearing assemblies are normally more bulky in size and also are separate elements that must be mounted on the boring tool. It is also known to provide individual guides within the bearing assembly that can be replaced. Additionally, springs or other resilient members may be placed behind the individual guides of the bearing assembly in order to allow the bearing member to fit into holes of varying sizes and/or to compensate for wear of the cutting tool. Since these known bearing members are short in length, they are not practical when boring holes that are interrupted by cavities, such as is present when boring cored holes in a valve body for a valve spool. It is also known to use a boring tool mounted on a boring bar with rigidly attached guides to enlarge previously machined holes. It is desirable to provide a boring tool that can be rebuilt without having to apply heat, such as that needed when removing and installing brazed in guides. In known boring bars having a length to cutting tool diameter of 6:1 or greater, the known boring bars have poor cutting performance due to chatter caused by the boring bar not being properly supported.
The present invention is directed to overcoming one or more of the problems as set forth above.
DISCLOSURE OF THE INVENTION
In one aspect of the present invention, a boring tool assembly is provided and adapted to have a cutting tool disposed on one end thereof to cut or bore a hole of a predetermined size in a member. The boring tool assembly includes a longitudinal extending boring bar having a plurality of slots defined therein about its circumference along its longitudinal length. Each of the slots has a top portion of a predetermined width, a bottom portion and opposed side walls. A hardened guide member having a predetermined width that is substantially the same as the width of the upper portion of the respective slots and is disposed in the top portion of each of the respective slots of the plurality of slots. A resilient member is also disposed in the bottom portion of each of the respective slots. Each of the respective resilient members is mechanically connected within the bottom portion of the associated slot and secured to the associated hardened guide member.
REFERENCES:
patent: 2283497 (1942-05-01), Fields et al.
patent: 2334795 (1943-11-01), Smith
patent: 4666350 (1987-05-01), Nicholas
patent: 5150496 (1992-09-01), Bromley
patent: 5957630 (1999-09-01), Endsley et al.
patent: 1315155-A (1987-06-01), None
Endsley John C.
Hinrichsen Michael H.
Bishop Steven C.
Burrows J. W.
Caterpillar Inc.
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