The present invention provides a fluidic clamping device (100) comprising a sleeve (110) for clamping and holding a movable part (200). The sleeve (110) comprises a central element (111) having a cross-section in a longitudinal direction of the central element (111), comprising a cavity configured to receive the movable part (200). The fluidic clamping device (100) is characterized in that the sleeve (110) further comprises at least one chamber (112) disposed on an outer periphery of the central element (111) and extending along a longitudinal direction of the central element (111), the at least one chamber (112) configured to containing a fluid, wherein the fluidic clamping device (100) is configured to pressurize an interior of the at least one chamber (112) with a first predetermined fluidic pressure or a second predetermined fluidic pressure, wherein the first predetermined fluidic pressure is lower than the second predetermined fluidic pressure, and wherein the central element (111) is configured to be in frictional contact with the movable part (200) at at least a portion of an inner periphery of the central element (111) and to clamp and hold the movable part (200) in a first state in which the interior of the at least one chamber (112) is pressurized with the first fluidic pressure, and wherein the central element (111) is configured not to be in frictional contact with the movable part (200) at any portion of the inner periphery of the central element (111) in a second state in which the interior of the at least one chamber (112) is pressurized with the second fluidic pressure.

A cylinder case includes a first main path communicating first port with an end surface, a second main path communicating a second port with the end surface, first and second front chamber paths respectively communicating a front chamber with the end surface, and first and second rear chamber paths respectively communicating a rear chamber with the end surface. A manifold block includes a first intermediate path communicating first and second manifold holes opened in an abutting surface with each other and a second intermediate path communicating third and fourth manifold holes opened in the abutting surface. The manifold block configured to be attached and fixed to the cylinder case such that the abutting surface is abutted against the end surface and a relative position of the abutting surface with respect to the end surface portion is capable of being selected from a first position and a second position.

A pulling device for generating a pulling movement in a clamping device has a pull-acting hydraulic working cylinder with a pull piston displaceable therein and a pull rod connected to the pull piston. In order to make the pulling device particularly compact and easy to maintain, the pulling device also has a push-acting hydraulic pump cylinder with a pump piston displaceable therein and a fluidic connection between the pump cylinder and the working cylinder. A movement of the pump piston in a pushing direction causes the hydraulic fluid to flow from the pump cylinder into the working cylinder, where it causes a pulling movement of the pull piston in a pulling direction. The pulling direction is opposite to the pushing direction, and the pump cylinder and the working cylinder are arranged coaxially to each other.

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 chuck assembly comprising a mandrel portion including an extending member sized and shaped to hold a workpiece; and a piston including a bore receiving the extending member, the piston mounted for supported movement on and relative to the extending member, the piston moving between a first position and a second position, the first position providing for insertion and removal of the workpiece to and from the extending member, the second position causing gripping force to be applied to the workpiece in at least two locations that are spaced longitudinally along the workpiece to inhibit relative movement between the mandrel and the workpiece.

A main spindle device includes: a main spindle; a rod accommodated in the main spindle, the rod being capable of moving to an unclamp position in a direction toward the first end, and when the main spindle is holding a tool, being capable of moving to a clamp position in a direction toward a second end; a biasing unit that biases the rod in the direction toward the second end with respect to the main spindle and that biases the rod to the clamp position when a collet is holding the tool; and a biasing force detector that detects a biasing force of the biasing unit which biases the rod in the direction toward the second end after the rod is moved in the direction toward the first end with respect to the main spindle to the unclamp position by force larger than the biasing force of the biasing unit.

A hydraulic chuck device includes a cylinder portion operated by pressure oil, a chuck opened and closed by operation of the cylinder portion, a pressure oil supply controlling pressure of pressure oil supplied to the cylinder portion, and a chuck controller controlling the pressure oil supply. When controlling the pressure oil supply to cause a jaw portion to perform a clamping operation, during movement of the jaw portion from an unclamping position to a preliminary position situated before a clamping position, the chuck controller supplies pressure oil set at a first pressure into a cylinder chamber for clamping to move the jaw portion quickly, and during movement of the jaw portion from the preliminary position to the clamping positon, the chuck controller supplies pressure oil set at a second pressure lower than the first pressure into the cylinder chamber for clamping to move the jaw portion slowly.

A control method of controlling a chuck device in a drive system for driving the chuck device, comprising opening or closing fingers by opening a switching valve at a first degree of valve opening to supply the fluid to a first cylinder chamber of the chuck device and to discharge the fluid from a second cylinder chamber of the chuck device so that a piston moves in one direction, and stopping the fingers in an intermediate position between a fully open position and a fully closed position by opening the switching valve at a second degree of valve opening to stop supplying the fluid to the first cylinder chamber and to stop discharging the fluid from the second cylinder chamber when the axial position of the piston reaches a target position set in advance while the fingers are being opened or closed.

A drive system for driving a chuck device includes a controller and a switching valve, which is a 5-port servo valve, switching the state of supply of compressed air to the chuck device based on a valve command signal from the controller. During switching of first and second fingers from a closed position to an open position, when the axial position of a piston reaches a switch point, which is a predetermined distance short of a target position corresponding to a freely selected intermediate position of the first and second fingers, the switching valve is opened at a third opening for a predetermined period and then switched to be opened at a fourth opening so that supply and discharge of compressed air are stopped. As a result, the first and second fingers stop in the intermediate position.

A clamping device for releasably holding a tool holder shank includes a spindle rotatably mounted inside 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, an actuating member slidably mounted to the spindle, a motion transferring mechanism for transferring an axial movement of the actuating member into a movement of the drawbar, and a hydraulic actuator with a piston unit for moving the actuating member. A valve assembly with two parallel and oppositely directed check valves provides a residual hydraulic pressure in a hydraulic chamber of the hydraulic actuator that will affect an automatic return movement of the piston unit after a movement of the drawbar to a retracted locking position.