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.

The main spindle device for a machine tool is provided with: a bearing for rotatably supporting the main spindle; a bearing case for holding the bearing; a housing inside which the bearing case is disposed; and a stiffness-switching device, which supports the bearing case with respect to the housing and is able to switch the stiffness of the bearing case support between multiple levels. When the stiffness-switching device is supporting the bearing case at a low stiffness, the main spindle device is formed so that the bearing case slides with respect to the housing. A friction member is disposed on the area where the bearing case slides with respect to the housing.

To provide a clamp device which is designed to shorten a spindle than before, thus enabling the downsizing of a spindle device.

In a clamp device for removably mounting a tool holder to a spindle of a rotary spindle device, a clamp mechanism is placed in a clamp state by a reciprocation drive mechanism producing a rearward movement in which a draw-in sleeve (9) engaged therewith via steel balls (13) is moved rearward to bring through-holes (12) thereof to rearward large diameter portion (4d) in a bore region of a spindle body (4) and further rearward to a position where the steel balls (13) are retained between the rearward large diameter portion (4d) and a jig large diameter portion (14a), while the retreated draw-in sleeve (9) moves rearward a draw-in bolt (8) and a clamp sleeve (5) by means of a biasing force of an elastic member (10).

A spindle apparatus according to the present disclosure includes a housing, a spindle rotatably installed in the housing, a tool releasably engaged with one end of the spindle and having an insert tip movable in a radial direction of the tool, a first draw-bar movably mounted in the spindle, and a second draw-bar movably mounted in the first draw-bar. The tool and one end of the first draw-bar are releasably engaged with the one end of the spindle by a movement of the first draw-bar, and the insert tip is configured to move in the radial direction by a movement of the second draw-bar.

A clamping assembly for a clamping device for clamping of a workpiece or tool or a toolholder on machine component with a clamping cone movable axially via a tension rod and several clamping elements arranged spaced from each other in the peripheral direction on the outside of the clamping cone, which can be moved between a radially outer clamped position and a radially inner released position by axial movement of the tension rod. The clamping cone includes two parts movable opposite each other in the axial direction.

The invention relates to an axle arrangement (10) for mounting a tool or a workpiece. The axle arrangement (10) comprises a receiving unit (12) that is supported by a swivel bearing assembly (13) in a base body (11) so as to be rotatable about a longitudinal axis L. The receiving unit (12) has a receiving sleeve (18) that is supported so as to be immovable in longitudinal direction R parallel to the longitudinal axis L and has a gripper actuating element (23) that is supported so as to be slidable in the receiving sleeve (18) along the longitudinal axis L. On one end of the gripper actuating element (23) associated with the front end (18a) of the receiving sleeve (18), there is seated a gripper unit (24) for gripping the tool or the workpiece. The gripper unit (24) is pretensioned by a pretension unit (30) in a clamping position I. An actuatable release unit (34) can move the gripper unitcounter the pretension force FV of the pretension unit (30)into a release position II. By means of a support unit (48), an auxiliary bearing (49) that, in particular, is configured as an axial bearing, can be pressed against the receiving sleeve (18) in order to achieve an improved axial force support of the receiving unit (12) on the base body (11) and to reduce the load on the swivel bearing assembly (13) due to axial forces.

In one aspect, cam bolts are described herein employing a dual cam surface architecture. In some embodiments, a cam bolt described herein defines a longitudinal axis and comprises a first end, a second end, at least one engagement member disposed on at least one of the first end and the second end, at least two first cam surfaces, and at least one second cam surface. The engagement member is configured to engage a torque implement to rotate the cam bolt about the longitudinal axis when torque is applied by the torque implement. The first cam surfaces are disposed about the longitudinal axis and have a first cam profile. The second cam surface is disposed about the longitudinal axis between the first cam surfaces and has a second cam profile differing from the first cam profile. At least one of the first and second cam profiles can be non-circular.

An electrospindle device includes at least one electrospindle extending about a vertical axis, the electrospindle including a motor, a shaft that rotates for transmitting motion, and an engagement portion for a toolholder in which a tool rotatably actuated by the shaft is mounted, the tool being actuated directly by the shaft; at least one toolholder support element including at least two toolholders; and at least one device for rotating the at least one toolholder support element, wherein operation of the at least one device for rotating the at least one toolholder support element brings a selected one of said at least two toolholders into vertical alignment with the engagement portion and extending in the vertical axis.

A clamping device for clamping a workpiece or a tool or, more specifically, a tool holding fixture in a machine part of a machine tool includes a tension rod slidably mounted within the machine part; a clamping set movable by the tension rod between clamped and released positions; a tension spring dedicated to the tension rod so as to generate the pull-in force of the clamping set; and a release mechanism, by which the clamping set can be moved against the force of the tension spring into the released position by the tension rod. To make possible effective clamping at optimum force, the tension spring is clamped between first and second rod parts of the tension rod. The second rod part can move relative to the first rod part, and, as the clamping set moves into the released position, is compressed on both ends by the release mechanism by moving the two rod parts in opposite directions.

A machine tool includes: a column; a spindle head supported by the column; a spindle in the spindle head; a draw bar moved upward to clamp a tool to the lower end portion of the spindle and moved downward to release the tool therefrom; a biasing portion biasing the draw bar upward; a cam mechanism including a cam in the column and an arm whose one end slides on a cam surface such that the other end pushes down the draw bar; a measurement portion measuring the position of the draw bar; a storage portion storing a position relationship between the spindle head and the draw bar when the cam mechanism is normal; and an abnormality determination portion determining an abnormality in the cam mechanism based on the position of the draw bar measured with the measurement portion and the relationship stored in the storage portion.