Abstract: A bearing unloading mechanism for a disc clamping unit utilized in rigid disc certifiers or testers comprises a hollow spindle (12) containing a pulling rod (20) which slides in the spindle. The upper end of the pulling rod carries a clamping element (26) for clamping a disc (D) to be tested or certified. There is a first compression spring (32) arranged between a flange (30) at the lower end of rod (20) and second compression springs (56) between stationary casing (18) and a moveable casing (48) which is attached to a pneumatic cylinder (40), solenoid, or any other linear actuator. When the actuator is energized, the moveable casing moves down, compressing the second springs until the moveable casing comes into contact with an abutment flange (58) of the spindle. At this point the device continues to move the rod connected to the clamp up to the unclamped position.