Rotatable platform assembly

A rotatable platform assembly comprising:

• upper and lower horizontal frames, said lower frame being wider than said upper frame and said upper frame being longer than said lower frame,
• a vertical post fixed to the lower of said frames and extending upwardly through the upper of said frames, said upper frame being journaled on said post for rotation in a horizontal plane about the axis of said post, said post being situated at a substantial distance from the lengthwise center of the upper of said frames,
• a ring member fixed to said lower frame, said ring member having an outer cylindrical surface coaxial with said post and an annular horizontal track surface coaxial with said post, said ring member having a diameter greater than the width of said upper frame,
• a plurality of rollers mounted on the upper frame and in rolling engagement with said track surface of said ring member,
• a chain sprocket mounted on said upper frame for rotation about a vertical axis,
• an endless roller chain trained around said outer cylindrical surface of said ring member and said chain sprocket,
• means engageable with said roller chain at spaced apart points lengthwise of said chain for holding said roller chain against lengthwise movement relative to said outer cylindrical surface of said ring member,
• manually controllable drive means mounted on said upper frame for rotating said chain sprocket about its axis.

In a chain drive system:

• a ring member having a cylindrical outer surface,
• a plurality of pin members on and projecting outwardly from said cylindrical outer surface of said ring member, said pin members being spaced around said ring member,
• a plurality of pad members mounted on and spaced around said cylindrical outer surface of said ring member, with at least one pad member being disposed between each two adjacent pin members, each pad member having a pad head spaced outwardly from said cylindrical outer surfaces of said ring member,
• a chain sprocket spaced outwardly from said ring member and having an axis parallel to the axis of said ring member,
• an endless roller chain trained around said cylindrical outer surface of said ring member and said sprocket, said roller chain being engaged by a plurality of said pin members and in abutment with said pad heads of a plurality of said pad members.