The present disclosure provides a jaw assembly for mounting to a lathe spindle. The jaw assembly comprises a first jaw set with at least one axially extending jaw portion which comprises a channel extending in the same axial direction as the jaw portion, and a second jaw set locatable within and releasably attached to the first jaw set via at least one fastener locatable in the channel.

A chuck for a machine tool includes a body rotatable about a rotation axis and defining a plurality of slots extending radially in the body, a plurality of jaws received in corresponding ones of the plurality of slots, the jaws being radially movable relative to the body between an inward position and an outward position, and for at least one of the plurality of jaws, a sealing layer disposed in the slot receiving the at least one of the plurality of jaws and sealing an interface between opposed lateral sides of the at least one jaw and a surface of the body defining the slot receiving the at least one of the plurality of jaws. A method of sealing an interface between a surface defining a slot of a chuck is also described.

A horizontal lathe for manufacturing a porous optical fiber preform, the horizontal lathe being configured to hold and fix two opposite ends of a target in such a manner that a longitudinal direction of the target is a substantially horizontal direction, and cause the target to be rotated around an axis parallel to the longitudinal direction thereof as a rotation axis. The horizontal lathe includes a thermal expansion absorbing mechanism configured to absorb a change in dimension of the target, the change being due to thermal expansion of the target in a direction of the rotation axis.

In the case of a clamping device (1) for holding a workpiece (3) to be machined by a machine tool (2), which is used in particular as a clamping chuck, vice or zero point clamping system, consisting of a housing (4), a supporting element (6), which is a component of the housing (4) or is fastened thereto, and thereby forms a supporting surface (6'), on which the respective workpiece (3) rests during the machining process, at least one clamping jaw (7) that is mounted in the housing (4) so it is axially movable and a counter-stop formed by the housing (4) or an axially movable clamping jaw (8), between which the workpiece (3) is clamped in the region of the supporting surface (6') or at least three clamping jaws (7, 8, 9) mounted in the housing (4) so they are axially movable, between which the workpiece (3) is clamped in the region of the supporting surface (6'), a reliable and verifiable monitoring of the distance between the workpiece (3) and the supporting surface (6') and/or the clamping jaws (7, 8, 9) is supposed to take place at the clamping device (1) before and during the entire machining process, without extensive constructional measures being required for this. This is achieved in that at least one free space (11) is integrated in the housing (4), the axis of symmetry of which runs perpendicular to the supporting surface (6') and which faces the clamped workpiece (3) with the open front side, and/or that at least one free space (11) is integrated in one of the clamping jaws (7, 8, 9), which free space leads to the respective clamping surface (7', 8', 9') of the clamping jaws (7, 8, 9), that a proximity sensor (12) is inserted in the respective free space (11), that, via the proximity sensor (12), a monitoring area (13) is formed between the supporting surface (6') and the workpiece (3), which is monitored by an analysis unit (14) with respect to the presence of the workpiece (3).

A chuck jaw stopping mechanism is disclosed for forming a soft jaw for a lathe. An example of the chuck jaw stopping mechanism includes a stopping device. The example chuck jaw stopping mechanism also includes a securement device configured to connect the stopping device on a master jaw of a chuck of the lathe. The example chuck jaw stopping mechanism also includes a lower surface of the stopping device that moves against a portion of an outer circumference of the chuck in a closed position. The lower surface also moves away from the portion of the outer circumference of the chuck in an open position to form a gap between the lower surface of the stopping device and the portion of the outside circumference of the chuck.

A method for determining the clamping force of a force-actuated, rotationally drivable clamping device of a machine tool. An object is clamped with an actuation force F. Model-based calculation of the clamping force F.sub.calc to be expected is performed based on the actuation force F and the operating parameters of the machine tool in a control unit of the machine tool. Performing clocked measurement of the clamping force F.sub.real acting upon the object in the clamping device within the time span of a measurement interval I. Wireless transming the measured value F.sub.real to the control unit of the machine tool, and comparison of the measured value F.sub.real with the calculated clamping force F.sub.calc. The measurement interval is adapted if the comparison reveals a deviation which reaches a threshold value.

A tool holder has a holder body, a first clamping member, and a first fastening member. The holder body includes a fixation portion and a mounting portion located rearward of the fixation portion. The fixation portion has a front fixation surface facing in a forward direction, a cylindrical fixation bore opening out to the front fixation surface and extending rearwardly therefrom, and a longitudinally extending primary slot connecting the fixation bore to a fixation envelope surface. The first clamping member occupies a first clamping bore and traverses the primary slot. The first fastening member occupies a first fastening bore which intersects the first clamping bore and opens out to the front fixation surface. The fixation bore has a fixation bore first primary diameter which decreases and increases when the first fastening member is rotated in first fastening and first unfastening directions about the first fastening member axis, respectively.

A device according to the present disclosure is a workpiece retaining device 10 that retains a retained portion 110 of an axial-directional end portion of a workpiece 100 that is cylindrical. The workpiece retaining device 10 includes a core member 32 that is round and that comes into contact an inner perimeter face of the retained portion 110 of the workpiece 100, a pressing member 33 that presses an outer perimeter face of the retained portion 110 of the workpiece 100 to an inner side in a radial direction, and an aligning member 44 that, upon a pressing force from the pressing member 33 acting thereupon, allows the core member 32 to move in the radial direction, in accordance with a magnitude and a direction of the pressing force.

An object of the present invention is to obtain information corresponding to information, which is readable by sight, but no longer visible. The present invention provides a chuck mechanism comprising: a chuck body including an installation surface and a side surface; and a master jaw provided on the installation surface of the chuck body and configured to move in a radial direction of the chuck body, wherein a first marking is provided on the installation surface of the chuck body, the first marking is product information of the chuck mechanism, the product information has a readable form by sight, and at least one second marking is provided on the installation surface or the side surface of the chuck body, the second marking is information including at least the product information of the first marking, and the information of the second marking has a coded form.

An object of the present invention is to obtain information corresponding to information, which is readable by sight, but no longer visible. The present invention provides a chuck mechanism comprising: a chuck body including an installation surface and a side surface; and a master jaw provided on the installation surface of the chuck body and configured to move in a radial direction of the chuck body, wherein a first marking is provided on the installation surface of the chuck body, the first marking is product information of the chuck mechanism, the product information has a readable form by sight, and at least one second marking is provided on the installation surface or the side surface of the chuck body, the second marking is information including at least the product information of the first marking, and the information of the second marking has a coded form.