US Patent: 4,595,322
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| Spade drill bit
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Patentee:
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| Burke Clement (exact or similar names) - Knoxville, TN |
| Manufacturer: |
| Not known to have been produced |
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Patent Dates:
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| Applied: |
Jul. 06, 1984 |
| Granted: |
Jun. 17, 1986 |
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Joel Havens
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Description: |
| Pitts and Brittian - patent attorneys
Abstract
An improved spade type bit for use in drilling metal, masonry and the like. This bit has a replaceable transverse bar of hardened material in the tip thereof with symmetrical end surfaces sloping away from a central chisel point located on the axis of the bit. One of these surfaces is provided along its length with a groove extending from a cutting lip to the trailing edge, with the groove width and depth at the trailing edge having at least the same dimensions as at the cutting edge. Preferably the dimensions of the groove at the trailing edge are slightly greater than those at the cutting edge. The second of the surfaces has an outer portion with a reduced angle with respect to the axis of the bit as compared to the angle of the inner portion. This construction provides for the accurate drilling of holes in metal, masonry and the like and further accomplishes the drilling at increased penetration rates with the same or lower axial force applied to the bit. The replaceable feature facilitates accurate resharpening of the cutting edges as well as selecting a particular configuration and material for a given drilling operation.
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