Provided is a lathe capable of elongating the life of a shifter mechanism. A lathe comprises a spindle, a chucking unit, a power transmitting unit, a shifter, a claw, and a driving unit. The shape of an outer circumference of the shifter in a contact range and a first end of the claw in longitudinal section along the spindle axis is such shape as the acceleration “a” of the first end in the diameter direction with respect to the moving distance of the shifter moving in the direction of the spindle axis (Z-axis direction) at a constant speed is continuous both in a positive range and in a negative range where the contact range is a range of the outer circumference of the shifter in contact with the first end of the claw.

The present disclosure provides a spindle structure including a base, a spindle, a sliding member, a restoring mechanism, and a restriction member. The spindle is rotatably received in the base and forms a receiving room. An end of the receiving room is a blind end communicating exterior via a gas channel. The sliding member is slidably received in the receiving room, and two ends thereof are a piston and a driving portion respectively. A gas cavity is defined between the piston and the blind end. The sliding member tends to move toward the blind end due to the restoring mechanism. The restriction member is connected to the driving portion and radially deforms when the sliding member slides so as to fix or to release the tool-holder. The sliding member slides outward when the gas cavity is injected with gas via the gas channel.

A clamping device for releasably holding a tool holder shank is formed with an engagement bore in a rear end, and includes a housing having a bore in a forward end for receiving the tool holder shank, a drawbar reciprocally movable inside the housing and which in a forward end is provided with engagement means arranged to engage with an engagement formation inside the engagement bore of the tool holder shank, and which is formed with a drawbar aperture extending through the drawbar in a transverse direction of the same, and a cam shaft extending through the drawbar aperture. The cam shaft includes three cam formations and more precisely first and second spaced apart cam formations, which are journalled in seating apertures in the housing on opposite sides of the drawbar, and an intermediate third cam formation located between the first and second cam formations and positioned within the aperture of the drawbar. The drawbar is insertable into the bore from the forward end.

An apparatus and a system comprise a collet comprising a top portion and a bottom portion. The top portion comprises a threading means. The bottom portion at least comprises means for holding the collet from rotating and means for retaining an end mill. A master comprises a top portion and a bottom portion. The top portion is configured for engagement with a spindle of a milling machine. The bottom portion comprises a threading means for engagement with the threading means of the collet, wherein the master is retained by the spindle and the collet engages and disengages the master by rotation of the spindle. The milling machine operates under computer control during engagement and disengagement of the collet from the master.

A method of monitoring a tool clamping device mounted on a machine spindle, the clamping force of which tool clamping device is generated by a spring assembly which exerts a force in the direction of the clamping position on an actuating element actuating the clamping or the release of a tool or tool holder. In the method, the spring force and the displacement of the actuating element are continuously measured during the release and/or clamping of a tool or tool holder and recorded as functions of the time. These recorded functions are used to identify at least one parameter characteristic for the status of the tool clamping device. Based on the spring force and the displacement over time, a spring characteristic curve is plotted in the form of the spring force as a function of displacement, the analysis of which spring characteristic curve provides information about a number of characteristic parameters.

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 workholding apparatus (10) wherein a draw bar (22) effects chucking and de-chucking of a workpiece (W) and wherein un-seating of the workholding apparatus is effected by piston-like mechanisms (30) located in a machine spindle (2).

A machine tool clamping device for releasably holding a tool holder having a tapered shank and a knob protruding from the tapered shank, the clamping device having: a spindle, rotatable about an axis, and having a tapered socket at a lower end thereof and an axial passage, the tapered socket being complementary in shape to the shank of a tool holder. Clamping members are pinned to the spindle and extend into the axial passage, the clamping members being pivotal between a clamped position in which the clamping members clamp the tool holder knob, and an unclamped position in which the clamping members release the tool holder knob. A drawbar is slidable within the spindle axial passage between the clamping members, the drawbar having a surface that acts to pivot the clamping members between the clamped and unclamped positions depending on the position of the drawbar within the axial passage. A spring is arranged between the drawbar and the spindle to bias the drawbar to the clamped position.

The present disclosure provides a spindle structure including a base, a spindle, a sliding member, a restoring mechanism, and a restriction member. The spindle is rotatably received in the base and forms a receiving room. An end of the receiving room is a blind end communicating exterior via a gas channel. The sliding member is slidably received in the receiving room, and two ends thereof are a piston and a driving portion respectively. A gas cavity is defined between the piston and the blind end. The sliding member tends to move toward the blind end due to the restoring mechanism. The restriction member is connected to the driving portion and radially deforms when the sliding member slides so as to fix or to release the tool-holder. The sliding member slides outward when the gas cavity is injected with gas via the gas channel.

A rotating-tool main shaft includes a hollow ram, a hollow main shaft, a collet, a draw bar that moves the collet in the axial direction, a hydraulic cylinder that moves forwardly the draw bar, and a disc spring that moves backwardly the draw bar. The draw bar includes a spring catch which is retained in the hollow main shaft so as to be movable, and which catches the disc spring. The disc spring is placed in the hollow main shaft, and is placed within a distance that is at least a half of a distance from a tip of the draw bar to the spring catch in the axial direction.