A high-speed tool holder includes: a tool shaft for accommodating a tool at its first end, and a machine clamping part which is integrally connected to the tool shaft and forms an interface for clamping in the machine; with the tool shaft being substantially truncated circular cone-shaped, a first diameter at the first end with the tool insertion opening being smaller than a fifth diameter at the second end at the machine clamping part; and a portion of the substantially truncated circular cone-shaped tool shaft having an outwardly bulging, preferably spherical, shape between the tool insertion opening and the machine clamping part.

A cutting tool holding mechanism for detachably holding a cutting tool includes: a collet chuck configured to clamp and unclamp the cutting tool; a piston disposed deeper on the proximal side of the spindle than the collet chuck and configured to urge the collet chuck by the pressure of a fluid supplied from the proximal side of the spindle in the direction from the proximal side toward the distal end side of the spindle so that the collet chuck unclamps the cutting tool; a spool valve provided in the piston and configured to open thanks to centrifugal force at the time when the spindle is turned, so as to supply the fluid fed from the spindle side to the cutting tool.

A collet includes an axially rearward end and an axially forward end; a nose portion; a body portion having an outer surface and an inner surface for engaging a shank of a tool; a plurality of slots extending from the inner surface to the outer surface; and a plurality of coolant channels disposed within the collet between the plurality of longitudinally extending slots and extending entirely from the axially rearward end to the axially forward end of the collet. The slots include a first slot extending from the axial forward end to within an intermediary zone, a second slot extending from the axial rearward end to at least the tool holder engagement zone such that the second slot does not intersect the first slot, and a third slot from within the tool engagement zone to within the intermediary zone such that the third slot circumferentially overlaps the first and second slots.

A tool holder is provided comprising a base body for coupling with a drive spindle that can be driven rotatingly, whereon a clamping chuck for clamping a tool is provided, further comprising a damping element arranged between the base body and the clamping chuck, wherein the damping element is made of an elastomeric material or of a shape memory alloy, and wherein the clamping chuck is solely connected to the base body by means of the damping element.

A tool holder assembly includes a holder body, a pull stud and a flow adjustment unit. The holder body has a holder coolant channel extending through a first end and a second end thereof. The pull stud has an insertion potion, a grip portion, and a longitudinal passage extending through the insertion portion and the grip portion, and fluidly communicating with the holder coolant channel. The flow adjustment unit includes a connection tube that extends into the longitudinal passage and projects outwardly from the grip portion, a resilient member urging the connection tube to project outwardly from the grip portion, and a flow guide channel extending through the connection tube and fluidly communicating with the holder coolant channel.

A tool holder assembly includes a holder body, a pull stud and a flow adjustment unit. The holder body has a holder coolant channel extending through a first end and a second end thereof. The pull stud has an insertion portion, a grip portion, and a longitudinal passage extending through the insertion portion and the grip portion, and fluidly communicating with the holder coolant channel. The flow adjustment unit includes a connection tube that extends into the longitudinal passage and projects outwardly from the grip portion, a resilient member urging the connection tube to project outwardly from the grip portion, and a flow guide channel extending through the connection tube and fluidly communicating with the holder coolant channel.

In one aspect, expansion sleeves for pressure-activated tool holder apparatus are described herein. An expansion sleeve, for example, comprises a first end, a second end and a longitudinal axis extending between the first end and the second end. A first set of fluid chambers are proximate the first end of the sleeve and a second set of fluid chambers are proximate the second end, wherein fluid channels extend along the longitudinal axis to connect radially offset fluid chambers of the first and second sets.

A coolant discharger includes a rotator, a fluid passage, and a nozzle. The rotator is rotatable about a rotation axis together with a workpiece and has a through hole extending along the rotation axis. The fluid passage is provided in the through hole to supply a coolant toward the workpiece. The nozzle is connected to the rotator to be connected to the fluid passage to discharge the coolant from the nozzle toward the workpiece in a discharging direction away from the rotation axis. At least a part of the nozzle is movable along the rotation axis.

A machining toolholder including a body, a horn and a piezoelectric actuator is disclosed. The body includes a center through hole extending in the axial direction therein. The center through hole includes a first hole section and a second hole section. The horn includes a first section and a second section which are disposed coaxially and connected with each other. Part of the first section is slidably inserted into the first hole section. The second section is connected to the body and engaged with a tool. Part of the surface of the second section contacts with a wall surface of the second hole section. The piezoelectric actuator fits around the horn and is controllable to drive the tool to vibrate. With this design, the machining toolholder could have good stiffness and connection stability, and could resist to the stress effectively.

A cutting insert comprising a cutting tip and a base insert on which the cutting tip is mounted, the cutting insert being provided with a passage PA which is formed along a boundary surface between the cutting tip and the base insert so as to extend from a boundary part, in an upper surface of the cutting insert, between the cutting tip and the base insert to another boundary part, in a lower surface of the cutting insert, between the cutting tip and the base insert.