Arrangement for centering an information disc

DETAILED DESCRIPTION It is the object of the invention to provide a system of the type mentioned in the preamble, which system is suitable for the storage and the reproduction of substantially larger amounts of information on readily interchangeable information discs.
The invention is characterized in that the information disc has a substantially rigid carrier; the inner wall of the central opening in the information disc has an accurate finish; and the centering element engages at least one of the two inner walls, namely, the inner wall of the central opening of the information disc and the inner wall of the central recess in the turntable, via elastically deformable compensation means for elastically compensating for differences in diameter through elastic radial deformation.
The invention is based on the recognition that in order to accomplish the desired object a combination of the three aforementioned elements is necessary.
By the use of a rigid information disc, it has become possible to exert pressure forces on the inner wall of the central opening of the information disc for the purpose of centering the disc.
This is not practical in the case of flexible information discs.
It is also necessary that the central opening in the disc have a good quality finish and the centering element may, for example, form a unitary centering.
This means that the tolerance range for permissible differences in diameter can be reduced.
Because neither the central opening in the information disc nor the recess in the turntable can be manufactured with absolute accuracy, slight dimensional variations will occur, even in the case of tight tolerance ranges.
However, by the use of elastically deformable compensation means, the slight differences in diameter can be compensated for elastically.
These elastically deformable compensation means can be integrally manufactured from an elastic material with a comparatively high modulus of elasticity, so that when sufficiently high pressure is exerted, they are capable of compensating for the differences in diameter and, moreover, capable of offering sufficient resistance to the centrifugal forces which are exerted on the information disc during rotation