A 45 rpm record adaptor body is positioned at the center of the turntable and has a record supporting shelf on one side and a shoulder opposite said shelf. The distance from the inner edge of said shelf to the bottom of said shoulder is slightly greater than the hole diameter of a 45 rpm record so that...http://www.google.com/patents/US4559623?utm_source=gb-gplus-sharePatent US4559623 - 45 RPM Automatic play adaptor
