Core drill

A bit-removal assembly configured to be coupled to an output shaft of a power tool, the bit-removal assembly comprising:

• a first ring configured to be coupled to the output shaft for co-rotation therewith;
• a second ring supported on a retaining ring, the retaining ring coupled to the output shaft;
• a frusto-conical surface on at least one of the first or second rings;
• a wedge positioned between the first and second rings, the wedge being engaged with the frusto-conical surface;
• a collar defining a cam surface located radially outward of the wedge, the collar being movable between a locked position, in which the cam surface is in direct contact with the wedge to displace the wedge radially inward on the frusto-conical surface to separate the second ring from the first ring, and a released position, in which the cam surface is misaligned with the wedge to permit the wedge to move radially outward on the frusto-conical surface;
• a biasing member configured to urge the collar towards the locked position;
• and
• a washer coupled to the collar for co-rotation therewith,
• wherein the biasing member extends between a first protrusion formed on the first ring and a second protrusion formed on the washer, and
• moving the collar toward the released position moves the first protrusion toward the second protrusion to compress the biasing member.

A core drill comprising:

• a housing;
• an output shaft configured to rotate about a rotational axis, the output shaft having a threaded connection to which a core bit is threaded;
• and
• a bit-removal assembly removably coupled to the output shaft between a lower retaining ring and an upper retaining shoulder, the bit-removal assembly including:
• a first ring removably coupled to the output shaft for co-rotation therewith,
• a second ring selectively supported on the lower retaining ring,
• a frusto-conical surface on at least one of the first or second rings,
• a wedge positioned between the first and second rings, the wedge being engaged with the frusto-conical surface,
• a collar defining a cam surface located radially outward of the wedge, the collar being movable between a locked position, in which the cam surface is in direct contact with the wedge to displace the wedge radially inward on the frusto-conical surface to separate the second ring from the first ring, and a released position, in which the cam surface is misaligned with the wedge to permit the wedge to move radially outward on the frusto-conical surface,
• a washer disposed within the collar and coupled to the collar for co-rotation therewith, and
• a biasing member positioned between the washer and the first ring, the biasing member configured to urge the collar towards the locked position,
• wherein the biasing member extends between a first protrusion formed on the first ring and a second protrusion formed on the washer, and
• moving the collar toward the released position moves the first protrusion toward the second protrusion to compress the biasing member.