Retaining device for a block or suction element

A retaining device for a block or suction element (10) in a centering device for spectacle lenses, having

• a support (1), which has a longitudinal axis (2),
• a spherically dome-shaped bearing surface (3) on the support (1),
• a spherical dome (5), which is mounted on the support (1) and is complementary to the bearing surface (3),
• a holding element (6) in the spherical dome (5) for the block or suction element (10) with a contact surface (11) for an unprocessed lens (12), and
• a radius (R) of the bearing surface (3) and of the spherical dome (5), the mid-point (M) of which is located on the longitudinal axis (2) of the support (1), on the contact surface (11) for the unprocessed lens (12),
• characterized by cardanic mounting of the spherical dome (3) on the support (1) by means of a first slotted guide (4) for a sliding block (13), said guide extending perpendicularly to the longitudinal axis (2) in the support (1), and by means of a further, second slotted guide (14) in the spherical dome (5) for a second sliding block (15), said guide extending perpendicularly to the first slotted guide (4), the sliding blocks (13, 15) forming a nonrotatable connection between the spherical dome (5) and the support (1).