Nut runner system which includes holder table having tightening point at one end and coupling part at other end, and configured to hold plurality of bits, and nut runner main body including carrier coupled to wrist part of robotic arm, spindle supported by carrier, and bit changer coupled to spindle and which one of plurality of bits is attached. Coupling part of each of plurality of bits has an engaging hole coaxial with tightening point, and annular protrusion that continues in circumferential directions is formed in inner circumferential surface of engaging hole. Bit changer includes actuator, actuator made of engaging shaft to be inserted into engaging hole and operating pieces formed in engaging shaft, operating pieces moving between engaging position wherein operating pieces protrude radially outward from inner circumferential edge of annular protrusion and retracted position wherein operating pieces are retracted radially inward from inner circumferential edge of annular protrusion.

Electric spindle for numerical control machines structured to lock and rotationally drive a tool about a predetermined reference axis locally coinciding with the longitudinal axis of the tool; the electric spindle comprising: an outer structural casing that is structured to be rigidly attachable to a generic numerical control machine; an electric motor that is housed within the structural casing and is provided with a drive shaft, which projects/emerges with its front end outside the structural casing while remaining locally coaxial to the reference axis of the electric spindle; a rotating thrust-bearing bushing or sleeve, which is fitted in an axially rotatable manner on the front end of the drive shaft via interposition of a first set of annular rolling bearings, and is maintained coaxial to the reference axis of the electric spindle by a second set of annular rolling bearings, which are interposed between the rotating bushing or sleeve and the structural casing; and at least one disassemblable tool-holder head that is structured to be attachable, in a rigid and stable though easily releasable manner, to the front end of the drive shaft, is structured so as to accommodate and retain, in a rigid and stable though easily releasable manner, the shank of a generic tool for numerical control machines, and is provided with a peripheral crown that is dimensioned/structured to stably abut, selectively and alternatively, on the front end of the drive shaft or on the rotating thrust-bearing bushing or sleeve.

A toolholder assembly includes a toolholder having a toolholder shank with a non-circular cross-section, a base member having a bore with a non-circular cross-section that receives the toolholder shank, a canister positioned in the base member, a lock rod positioned in the canister, a locking ball for cooperating with the lock rod, the canister and/or the toolholder shank and an actuating element configured for cooperation with the lock rod for moving the lock rod between a locked position and an unlocked position.

According to a tool clamping device for a machine tool, when a draw bar is moved in the axial direction of the main shaft of the tool clamping device, a steel ball moves in the radial direction of the main shaft so as to press the inner wall of the main shaft, forming an impression on the inner wall of the main shaft. This forms an inclined surface for generating a magnification effect for magnifying a spring force.

In one aspect tool holder assemblies are described herein. Such tool holder assemblies can employ outer and inner spring-like members. For example, a tool holder assembly described herein comprises a drawbar having an outer diameter surface and an inner diameter surface defining an interior of the drawbar. The drawbar is movable or actuatable along a longitudinal axis between a locked position and an unlocked position. The tool holder assembly can further comprise a first spring-like member positioned around the outer diameter surface of the drawbar and a second spring-like member positioned in the drawbar interior.

[Object] To provide a spindle device capable of clamping two positions at the inside and the outside of a multifunctional holder with one driving means, a machine tool having the spindle device mounted thereon, and the like.

[Solution Means] In a spindle device to be used by mounting a holder having a first clamped part and a second clamped part arranged doubly on a spindle leading end, a first draw bar 8 and a second draw bar 9 overlap each other and are arranged in series in a spindle cylinder. As the first draw bar 8 is pushed and advanced by a striking metal 17, the first draw bar 8 is advanced against a biasing force of a first disc spring assembly 10 and a first clamping mechanism is released, and along with this, the second draw bar 7 is also advanced against a biasing force of a second disc spring assembly 11, and a second clamping mechanism is also released. As the striking metal 17 is retreated, the first and second clamping mechanisms of the first and second draw bars 8 and 9 are activated by the biasing forces of the first and second disc spring assemblies 10 and 11.

A tooling exchange mechanism and a machine tool having the tooling exchange mechanism, in which a load applied to a turret is reduced when exchanging a tooling in the machine tool, are provided with a pressing member 210 of a tooling detachment unit 200 that presses the rear end of a tooling holding unit 100 to be able to release the retracted state of a tool holder Th of a tooling T by a tool holder holding portion 150 of the tooling holding unit 100, and a locking lever 220 of the tooling detachment unit 200 engageable with an engaging projection 112a formed on the rear end side of the tooling holding unit 100.