PURPOSE: To prevent the biting of a finishing tap at the start of the work by providing a spring supporting a tap support body on a tapping holder and with a spring force equal to the total weight of the tap support body and a tap.
CONSTITUTION: The second cylinder 6 holding a tap 7 through a tap collet 8 is rotatably and slidably supported by the first cylinder 1 provided with a tapered section 1A connected to a main shaft. A spring 17 having a spring force equal to the total weight of the second cylinder 6, tap collet 8, and tap 7 is provided between a support shaft 3 fixed to the first cylinder 1 and second cylinder 6. Roller pins 22 and balls 21 are coupled in a groove 20 around the second cylinder 2 and a groove 19 on the inner periphery of the first cylinder 1, thus transmitting rotations to the second cylinder 6, which is energized by ring springs with ribs 13, 15 in contact with the step section 10 of the second cylinder 6, thus a thrust force is applied to the second cylinder during cutting.
KOMURA AKIO
TAKADA TOMIJI
KOBAYASHI MASAOMI
NIKKEN KOSAKUSHO KK