Rotary disc loading mechanism

A rotary disc loading mechanism comprising:

• a base plate;
• right and left guide arms rotatably mounted on said base plate in a plane parallel thereto and symmetrically with respect to its center line, for guiding and holding the peripheral margin of a disc in cooperation with each other, each of said right and left guide arms having a small-diametered disc holding portion for holding a small-diametered disc and a large-diametered disc holding portion for holding a large-diametered disc;
• a disc detect arm rotatably mounted on each of said right and left guide arms in a plane parallel to said base plate, said disc detect arm having a guide boss for controlling the rotational movement of said each guide arm and a projection for contact with the marginal edge of said large-diametered disc in said large-diametered disc holding portion;
• a bias spring connected between each of said right and left guide arm and said guide arm corresponding thereto, for biasing said projection of said disc detect arm toward said large-diametered disc holding portion at all times;
• and
• a toggle spring connected between each of said right and left guide arms and said base plate, for applying to said each guide arm a moment which reverses its direction when said each guide arm passes its predetermined rotational angular position relative to said base plate;
• wherein said base plate has a substantially L-shaped guide slot composed of a slot substantially extending along an arc coaxial with a rotary shaft of said each guide arm and a lock slot extending from one end of said arc-shaped slot almost at right angles thereto;
• said guide boss of said each disc detect arm is slidingly guide in said guide slot;
• and said projection of said each disc detect arm lies outside or inside said large-diametered disc holding portion of said each guide arm depending on whether said guide boss of said each disc detect arm stays in said arc-shaped slot or said lock slot of said guide slot.