Countersink core drill assembly and method of utilizing same
First Claim
1. A countersink core drill for use in drilling a stepped bore in a concrete slab, wall or the like comprising:
- concentric inner and outer core drills including a relatively long smaller diameter inner core drill having its forward end projecting substantially beyond the forward end of said larger diameter outer core drill;
a cutting ring attached to the forward end of each of said core drills;
means for detachably securing the rear ends of said inner and outer drills as a unit to the rotary shank of a power unit;
the main body of said inner drill having outlet openings in the wall thereof for a chip flushing fluid positioned rearwardly of the forward end of said outer drill; and
closure means for said outlet openings movably supported between the ends of said outer drill and movable between positions to control flow from said openings.
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Accused Products
Abstract
Disclosed is a core drill assembly and method of using the same to drill a countersunk hole through a concrete slab, wall or the like masonary member. The assembly utilizes concentric inner and outer core drills, the longer smaller one of which is provided with flushing fluid outlets rearwardly of the front end of the outer or countersink drill and provided with closure means for confining fluid flow to the inner drill when that drill is in use, and for diverting the flow to the outer drill while performing the countersink operation. The two drills have separate coupling facilities thereby permitting the substitution of drills of any selected relative sizes.
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Citations
9 Claims
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1. A countersink core drill for use in drilling a stepped bore in a concrete slab, wall or the like comprising:
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concentric inner and outer core drills including a relatively long smaller diameter inner core drill having its forward end projecting substantially beyond the forward end of said larger diameter outer core drill; a cutting ring attached to the forward end of each of said core drills; means for detachably securing the rear ends of said inner and outer drills as a unit to the rotary shank of a power unit; the main body of said inner drill having outlet openings in the wall thereof for a chip flushing fluid positioned rearwardly of the forward end of said outer drill; and closure means for said outlet openings movably supported between the ends of said outer drill and movable between positions to control flow from said openings. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. That method of drilling a countersunk hole in a concrete slab or wall, or the like which comprises:
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utilizing a pair of concentric inner and outer core drills wherein said inner drill is longer and smaller in diameter and protrudes forwardly beyond the front cutting end of said outer drill; providing means for holding said inner and outer drills detachably assembled to a rotatary power unit equipped with means supplying flushing fluid to said drills; utilizing said power unit to drive said inner drill and supply the same with flushing fluid while boring a hole through a concrete slab or wall; and substantially cutting off the flow of flushing fluid from the forward end of said inner drill and diverting the flow of flushing fluid into the interior of said outer drill while utilizing said power unit and said outer drill to drill a larger diameter countersunk bore centered about the inlet of said first drilled bore. - View Dependent Claims (9)
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Specification