A clamping module for a machine tool is proposed. The clamping module includes: a body having a mount hole that a pull stud enters; a plunger configured to clamp or unclamp the pull stud by sliding forward or backward radially from a center of the mount hole; a plunger pin protruding from a side of the plunger and configured to freely rotate; and a clamp plunger having a guide groove configured to move the plunger forward and backward by interfering with the plunger pin while moving up and down inside the body, in which the guide groove has a first guide face for moving forward the plunger to a clamping position and a second guide face for moving backward the plunger to an unclamping position; and the first guide face is an arc-shaped curved shape having a uniform radius of curvature.

Hollow shank tool holders including stress reduction features that result in a more reliable stronger tool holder are disclosed. The tool holders include an elliptical undercut contoured relief surface adjacent to the clamping surface to substantially reduce or eliminate a stress point. The elliptical undercut allows for no changes to be made to the clamping surfaces of the tool holder.

Hollow shank tool holders including stress reduction features that result in a more reliable stronger tool holder are disclosed. The tool holders include an elliptical undercut contoured relief surface adjacent to the clamping surface to substantially reduce or eliminate a stress point. The elliptical undercut allows for no changes to be made to the clamping surfaces of the tool holder.

An automatic device for locking of tool holders (12) on lathes and machinery performing machining by chip removal, particularly suitable to be used on multi-spindle and single spindle CNC lathes, on transfer machines, milling centres of any kind and, in general, on all types of machine tools which perform machining by chip removal, comprises a support body (14) anchored to the machine tool and surmounted by a plate (16), said device comprises, for each of said tool-holders (12), a pawl (18) provided with a female truncated-cone recess (24), cooperating with a nut screw (36) and moved automatically vertically to engage in contact with a truncated cone collar appendage (40) made in a recess (38) in the rear (12). The movement in the vertical direction of the pawls (18) is produced by means of individual motors (46), equipped with a shaft (48) which protrudes from their lower face and engages to the upper end of said nut screw (36).

An automatic device for locking of tool holders (12) on lathes and machinery performing machining by chip removal, particularly suitable to be used on multi-spindle and single spindle CNC lathes, on transfer machines, milling centres of any kind and, in general, on all types of machine tools which perform machining by chip removal, comprises a support body (14) anchored to the machine tool and surmounted by a plate (16), said device comprises, for each of said tool-holders (12), a pawl (18) provided with a female truncated-cone recess (24), cooperating with a nut screw (36) and moved automatically vertically to engage in contact with a truncated cone collar appendage (40) made in a recess (38) in the rear (12). The movement in the vertical direction of the pawls (18) is produced by means of individual motors (46), equipped with a shaft (48) which protrudes from their lower face and engages to the upper end of said nut screw (36).