Abstract: Disclosed is a claw unit with paired separably connected claw elements, which comprises a chuck body, a master jaw, a top jaw, position-limiting members, a locking member, and an engaging member. When the engaging member is rotated, the locking member which is in engagement with the engaging member is retreated into the master jaw from a front surface thereof. Thereafter, the top jaw is forced into the front surface of the master jaw. When the top jaw has been thus brought into engagement with the position-limiting members and further into contact with the front surface of the master jaw, the top jaw is moved somewhat in a radial direction of the chuck body. When, in this state, the engaging member is rotated, the locking member which has been elastically urged is allowed to rush into a positioning hole of the top jaw to lock the top jaw. Thus, the top jaw is made integral with the master jaw.

Abstract: A replaceable tool is comprised of a tool holder forming a hole providing an engageable ditch on the insert end of the shank, a fitted hole for detachably fitting the shank of this tool holder therein and a sleeve providing a plurality of locking balls to be engaged and removed from the fitted ditch of the tool holder in the fitted hole. In the interior of the fitted hole of the sleeve, the locking balls are pressed on the engageable ditch and the draw collar for applying attraction in the axial direction of the sleeve is slidably provided. When the shank of the tool holder is fitted in the fitted hole of the sleeve, the head portion end of the tool holder is designed to be pressed on the end flange portion of the fitted hole of the sleeve, and when the draw collar is pulled in the axial direction of the sleeve, the shank portion is expanded through locking balls so as to be pressed on the inner wall surface of the fitted hole of the sleeve.