| 摘要 |
Device for rotation of disc-shaped elements of different diameter, such as matrices for manufacturing audio and video discs. The device comprises a rotatable chuck (10) in which three arms (20) distributed evenly in the peripheral direction are pivotably mounted, the said arms having a radially outer stop element (22) for contact with an outer peripheral edge of a disc element inserted in the chuck. The chuck has a rotatably mounted central gearwheel (18) which is preloaded by means of tension spring elements (28) towards a rotational position in which the central gearwheel (18) tends to hold the arms (20) and their stop elements (22) in a pivoted-in position in the chuck. The arms (20) are synchronously pivotable towards a pivoted-out position counter to the action of the tension spring elements (28). The device comprises a retaining mechanism (30-40) which is designed to lock the rotation of the central gearwheel (18) relative to the base plate (16) when a predetermined speed of the chuck (10) is reached. <IMAGE> |
