SHANK ATTACHING STRUCTURE

摘要

A shank attaching structure enabling supply of a coolant even if a drill without a center pin is attached and the quick attachment and detachment of a shank (30) into and from a shank attaching hole (2) in one operation. The outer diameter of the shank (30) is so set that the shank can be inserted into the shank attaching hole (2). A chamfered part (33) is formed along the base end periphery the shank, and recesses (31) are formed in the distal end of the shank in the form of a slot. A coolant supply hole (3) is formed in a body part (1B) of the base end of the shank attaching hole (2), a valve element (5) is disposed in the hole (3), and a seal member (4) is disposed nearer to the distal end than the valve element (5) is. A first sleeve (20) is so disposed in the shank attaching hole that the first sleeve can be separated from the seal member when the base end of the shank abuts on the distal end of the first sleeve and is moved until its base end abuts on the valve element and that its peripheral surface having an outer diameter approximately equal to the diameter of the shank attaching hole can bring about a state that a locking member (15) is apart from the inner peripheral surface of the shank attaching hole (2) toward the outer diameter when the shank does not abut on the distal end of the first sleeve.