A clamping device for clamping a workpiece or a tool or a tool holder to a machine component of a machine tool, having an axially movable tension rod, a clamping assembly which can be moved by the tension rod between a clamped position and a released position, a spring assembly dedicated to the tension rod with a plurality of series-connected spring units for generating the clamping and draw-in force of the clamping assembly, and a releasing unit by which the clamping assembly can be moved by the tension rod against the force of the spring assembly into the released position. To ensure the most uniform load possible, the axial spring deflection of the spring units is limited by a stop when the spring assembly is compressed.

A collet adaptor (10) including a body (11, 12) having forward and rear ends and an axial bore (17) extending through the forward and rear ends. A drawbar (13) disposed at least partly within the bore (17) for connection to a collet (14). The drawbar (13) is secured within the bore (17) and a biasing arrangement (42) acts on the drawbar (13) in a direction tending to shift the drawbar (13) rearwardly within the bore (17). The drawbar (13) is displaceable within the bore (17) against the biasing influence of the biasing arrangement (42) to shift forwardly within the bore (17).

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.

A clamping device for releasably holding a tool holder shank includes a spindle rotatably mounted inside a housing. A drawbar is axially moveable in a bore in the housing between an advanced releasing position and a retracted locking position. A plurality of engagement members are moveable under the effect of the drawbar into locking engagement with the tool holder shank. An actuating sleeve is arranged around a peripheral wall of the spindle and axially moveable in relation to it. A motion transferring mechanism is arranged for transferring an axial movement of the actuating sleeve into a movement of the drawbar. A hydraulic cylinder arrangement is arranged for moving the actuating sleeve. The hydraulic cylinder arrangement includes a cylinder casing fixed to spindle and an annular piston head, which is fixed to or fixedly connected to the actuating sleeve and slidably received in an annular space inside the cylinder casing.

A clamping device for releasably holding a tool holder shank includes a spindle rotatably mounted inside a housing. A drawbar is axially moveable in a bore in the housing between an advanced releasing position and a retracted locking position. A plurality of engagement members are moveable under the effect of the drawbar into locking engagement with the tool holder shank. An actuating member is slidably mounted to the spindle. A motion transferring mechanism is arranged for transferring an axial movement of the actuating member into a movement of the drawbar. Two or more hydraulic actuators are arranged in or mounted on the housing on different sides of the spindle and configured to move the actuating member in relation to the spindle. A connecting element forms a connection in radial direction between the actuating member and piston members of the hydraulic actuators.

Disclosed is a machine tool ELECTRICAL DRIVING SYSTEM capable of selectively transmitting power of a motor for driving a spindle in a lathe which machines a workpiece to a rotation system including a drawbar and a spindle for driving a chuck, using a clutch mechanism. The machine tool ELECTRICAL DRIVING SYSTEM includes a housing, a hollow tubular spindle rotatably installed inside the housing, a drive pulley rotatably installed with respect to the spindle outside the spindle, a spindle motor, a drawbar installed to be linearly movable with respect to the spindle but non-rotatable relative to the spindle, a motion conversion unit configured to convert a rotary motion of the drive pulley into a forward-rearward linear motion of the drawbar, a clutch unit, a position detection unit configured to the drive pulley to detect an amount of rotation and a rotation position of the drive pulley, and a controller.

A clamping device for releasably holding a tool holder shank includes a housing, a drawbar axially moveable in a bore in the housing, engagement members moveable under the effect of the drawbar into locking engagement with the tool holder shank, and an actuating member rotatably arranged in the bore. Upon rotation of the actuating member, a contact surface on a motion transferring element fixedly connected to the actuating member achieves an axial movement of the drawbar by pressing against a contact surface on another motion transferring element fixedly connected to the drawbar. At least one of the contact surfaces includes two sections with mutually different pitch, such that the same angular displacement of the actuating member, when rotated in a first rotary direction, results in a longer axial movement of the drawbar in a first phase of the rotary movement than in a final phase thereof.

A machine tool electrical driving system includes a housing, a hollow tubular spindle rotatably installed inside the housing, a drive pulley rotatably installed with respect to the spindle outside the spindle, a spindle motor, a drawbar installed to be linearly movable with respect to the spindle but non-rotatable relative to the spindle, a motion conversion unit configured to convert a rotary motion of the drive pulley into a forward-rearward linear motion of the drawbar, a clutch unit, a position detection unit configured to the drive pulley to detect an amount of rotation and a rotation position of the drive pulley, and a controller.

[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.

Provided is ram clamping system (100) comprising a rotationally symmetrical main body (110), which has an opening that passes through the rotationally symmetrical main body (110) along its axis of symmetry, in which opening a drawbar (140) extends, comprising a collet (120) which can be clamped by means of the drawbar (140) for fixing a ram (190) associated with the ram clamping system (100), and comprising an exchangeable holder (180), through the interior (181) of which the ram (190) passes before entering the collet (120), wherein at least one portion of the collet (120) projects in the direction of extension of the drawbar (140) beyond the end face of the main body (110), on which end face the exchangeable holder (180) is arranged, and enters the interior (181) of the exchangeable holder (180).