Patent Number: 6,250,856

Title: Quick attachment structure for drill shank

Abstract: A shank fitting structure simple in structure and easy to machine and assemble. A shank (20) has an external diameter large enough to allow it passage in a state where a detent member (5) is moved bach radially outward, and includes a stepped portion (21) for butting by providing a small diameter portion on the end side an d a recess (23) for housing the projecting part of the detent member (5) formed in the tip part. On the internal circumferential face of an opening part (2) of an arbor A, a first sleeve (6) is provided and pressed by an elastic member (8) toward the edge of the opening in such a way that its tip comes into contact with the stepped portion (21) of the shank (20) and its external circumferential face can keep the detent member (6) back toward the external circumference. A holding hole (9) for holding the detent member (5) within the range of its sliding movement is made in the wall of the arbor A, and a second sleeve (3) capable of being moved back toward the base end and pressing the detent member radially inward by the inner circumferential face when the second member is moved back toward the base end is disposed on the external circumferential face of the arbor.

Inventors: Miyanaga; Masaaki (Miki, JP)

Assignee: Kabushiki Kaisha Miyanaga

International Classification: B23B 31/10 (20060101); B23B 31/107 (20060101); B23B 51/04 (20060101); B23B 031/22 (); B23B 051/00 ()

Expiration Date: 06/26/2018