Centring device for optical video disc - provides more accurate centring by providing thin metal plate with precision drilled hole

摘要

Compact video discs which have very narrow data tracks (a,b,c,d) must be accurately centred on the rotation spindle of the player. If the perspex disc itself is drilled, the hole may be ragged, oval or otherwise distorted. The present device is a small thin metal plate (3) which can be attached to a disc over an oversize opening (2) in the centre. The plate which has an accurately drilled round hole (4) is positioned precisely and attached to the perspex disc. The plate, which is thicker than 0.1 mm and may be produced by electrolytic processes, is glued to the disc surface, set into a rebate or attached to the disc by pressing claws into the perspex. An alternative version uses a thicker tapered collar.