Abrading – Machine – Combined
Reexamination Certificate
1999-09-17
2001-06-12
Rose, Robert A. (Department: 3723)
Abrading
Machine
Combined
C451S375000
Reexamination Certificate
active
06244938
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to a drill grinder, and, more particularly, to a portable drill grinder useful for sharpening a drill point.
Portable drill grinders useful in machine shops and the like have been available for decades. One of the original basic disclosures relating to such grinders is found in U.S. Pat. No. 2,109,308 for a drill grinder issued Feb. 22, 1938, incorporated herewith by reference. A companion patent disclosing a portable drill grinder and setting forth information regarding the technology of grinding drill points on drill bits is U.S. Pat. No. 2,124,093 for a grinding machine issued Jul. 19, 1938. Subsequent patents relating to drill grinder constructions include U.S. Pat. No. 4,001,975 and U.S. Pat. No. 4,093,247. Other patents relating to this general technology include U.S. Pat. No. 4,485,596 and U.S. Pat. No. 4,471,581.
Typically, drill grinders of this type include a grinding wheel, which is mounted on a platform. A collet or chuck is provided to receive and hold a drill bit. A bracket is provided to support the collet in opposition to the grinding wheel. The collet is manipulated in the bracket to engage the point of the drill bit against the grinding wheel and thereby grind or sharpen the drill bit in accord with the manner in which the collet is manipulated within the bracket. Collet manipulation is controlled by compatible cams and followers on the collet and bracket. Nonetheless, adjustment of the collet and manipulation of the drill bit within the collet to effect proper forming of the point of the drill have long been challenging problems.
The present invention relates to a drill grinder which addresses the manner in which the bracket that supports the collet or chuck may be moved with respect to the grinding wheel to effectively grind the drill point. The invention also is directed to the collet construction as well as mechanisms for properly aligning a drill bit within a collet in order to enhance the point forming operation, including split point forming and thin web formation on a drill point.
SUMMARY OF THE INVENTION
Briefly, the present invention comprises a drill grinder which includes a mounting platform with a grinding wheel fixed on the mounting platform. A subplatform or assembly plate is slidably mounted on the mounting platform for translational movement in a direction parallel to the rotation axis of the grinding wheel. A bracket or fixture on the subplatform is mounted in a manner which permits feeding or movement of a collet or chuck which holds the drill bit in a direction perpendicular to the rotational axis of the grinding wheel. Feed mechanisms for the plate and bracket are provided. The collet or chuck is adapted to receive a drill bit of any one of multiple sizes and includes a removable conical front portion or section which enables conversion of the collet for acceptance of large size drill bits and smaller size drill bits.
A special drill bit orientation fixture or bracket is provided to facilitate orientation of the drill bit in the collet or chuck so that the point of the drill bit will be properly oriented in the collet or chuck with respect to the grinding surface of the grinding wheel in order to grind and sharpen the drill bit point in an effective manner when the collet is properly placed in the bracket mounted on the subplatform.
A further fixture or bracket is provided for supporting the collet or chuck in proper juxtaposition to a grinding wheel to form a split point or a thin web on the drill bit point.
Thus, it is an object of the invention to provide an improved drill grinder which includes a mounting platform assembly that enables positioning of the point of a drill bit against the surface of a grinding wheel in a manner that is highly adjustable.
It is a further object of the invention to provide an improved drill grinder assembly or construction which includes a unique collet for holding a drill bit and which permits adjustment of the collet for multiple sizes of drill bits.
Another object of the invention is to provide a drill grinder which includes a fixture that will ensure proper orientation of the drill bit in a collet or chuck for grinding of the point of the drill bit.
Another object of the invention is to provide a drill grinder which is economical, rugged, easy to transport and highly reliable.
These and other objects, advantages and features of the invention will be set forth in the detailed description which follows.
REFERENCES:
patent: 2109308 (1938-02-01), Adams
patent: 2124093 (1938-07-01), Wells
patent: 2536823 (1951-01-01), Smith
patent: 2556073 (1951-06-01), Dixon
patent: 4001975 (1977-01-01), Bernard et al.
patent: 4093247 (1978-06-01), Bernard et al.
patent: 4471581 (1984-09-01), Bernard et al.
patent: 4485596 (1984-12-01), Bernard et al.
patent: 5649853 (1997-07-01), Kuo
Banner & Witcoff , Ltd.
Lisle Corporation
Rose Robert A.
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