Acoustic damping turntable and adapter

Claim 1

In a turntable for recording discs: a. a turntable having a record bearing surface thereon; b. means supporting said turntable for rotation about its axis; c. a spindle pin carried by the turntable extending axially upwardly of the bearing surface for centering recording discs on said turntable; d. a sleeve guidingly mounted on said spindle pin for slidable movement thereon; e. means determining an upward limit to the movement of said sleeve; f. spring means carried by the turntable for urging said sleeve towards its said upper limit; g. a composite integral adapter ring of acoustic damping material and secured to said sleeve for mounting thereby and movement as a unit therewith, said adapter ring having an upper small diameter part and a lower large diameter part adapted respectively to engage the spindle holes of larger and smaller diameter recording discs; h. said composite adapter ring also having a substantially flat pad part at the base of said small diameter part and extending to the top of said large diameter part; i. means forming a recess in said turntable for receiving said adapter ring with said pad part coplanar with said bearing surface when said pad part is engaged by a recording disc with a smaller spindle hole; j. said spring yielding upon application of the weight of said smaller spindle hole recording disc; k. the coupling between said spindle pin and said recording discs for centering thereof being dependent upon the acoustic camping material of said adapter ring; l. said record bearing surface comprising a pad of foam rubber-like acoustic damping material, said pad having a plurality of surface separated contiguous interfitted annular sections, the innermost annular section forming at least the upper part of said turntable recess, acoustic vibrations from the turntable to a recording disc mounted on said bearing surface being dependent for their transmission either upon said pad or said composite adapter ring.