Tone arm assembly

A phonograph assembly comprising:

• (a) a pivotable tone-arm sub-assembly comprising an elongated tone arm, a counterweight positioned toward one end of said tone arm, and a head shell adapted for mounting a cartridge in an operative position toward the opposite end of said tone arm, said cartridge comprising a stylus fixed to a stylus cantilever, said catridge cantilever having a longitudinal axis;
• (b) a unipivot bearing for supporting said sub-assembly for pivotal movement about a pivot point, said pivot point being positioned with respect to the center of gravity of said sub-assembly such that displacing said tone arm sub-assembly and operably positioned cartridge from any given position by pivoting it generates no appreciable force tending to restore said tone arm to said given position;
• and
• (c) lateral balancing means comprising two balancing members extending outwardly from opposite sides of said tone arm sub-assembly, said members being positioned so that an axis running from one said member to the other said member is perpendicular to said stylus cantilever axis and intersects a vertical line through said pivot point slightly below said pivot point;
• whereby said assembly is in a balanced condition such that (1) said counterweight can be adjusted to create a desired tracking force, (2) said lateral balancing means defines a preferred vertical pivoting plane perpendicular to said axis running between said lateral balancing members, thus providing a beam balance force resisting rotation of said elongated tone arm about its longitudinal axis and maintaining said stylus cantilever in said preferred pivoting plane during vertical pivoting of said tone arm, and (3) vertical pivoting of the tone arm over a warped record does not generate appreciable restoring force, thus maintaining said tracking force substantially constant during said vertical pivoting.