A clamping device includes a first clamping segment which has a first mounting flange and a tubular member extending axially away therefrom. A first bore extends through the first mounting flange and the tubular member. The first mounting flange is configured for attachment to a rotatable spindle of a machine tool. The clamping device includes a draw bar assembly which has an axially extending elongate shaft. The elongate shaft extends through the first bore of the first clamping segment. A biasing unit is mounted on or in the tubular member. A locking member is removably secured to the elongate shaft such that the biasing unit is compressed between the locking member and a portion of the first clamping segment. The biasing member remains compressed when the first clamping segment is separated from the spindle of the machine tool.

A clamping device includes a first clamping segment which has a first mounting flange and a tubular member extending axially away therefrom. A first bore extends through the first mounting flange and the tubular member. The first mounting flange is configured for attachment to a rotatable spindle of a machine tool. The clamping device includes a draw bar assembly which has an axially extending elongate shaft. The elongate shaft extends through the first bore of the first clamping segment. A biasing unit is mounted on or in the tubular member. A locking member is removably secured to the elongate shaft such that the biasing unit is compressed between the locking member and a portion of the first clamping segment. The biasing member remains compressed when the first clamping segment is separated from the spindle of the machine tool.

A gripper device (100) for maintaining, centring, and/or clamping a micromechanical or horological component (200) in a clamping chamber defined by a clamp including at least one mobile jaw (2). At least a part of the mobile jaws (2) includes a reference surface (20) for frontal bearing of a component (200), and the gripper device (100) includes a vacuum generator (60) for creating the vacuum in the clamping chamber. Also, a method for fastening a micromechanical or horological component (200) in the clamping chamber of such a gripper device (100) according to which the component (200) is disposed on the reference surface (20), then a first maintaining by vacuum is carried out, then a second maintaining having a torque greater than that of the first maintaining by pivoting of the mobile jaws (2).