Tone arm system for record turntable
US4127274A · kind A · utility
Inventor
Key dates
| Filing date | Jan 12, 1978 |
| Grant date | Nov 28, 1978 |
| Priority date | — |
| Expiry date | Jan 12, 1998 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B3/091
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
For use with a turntable structure for rotating a sound-recorded disc, an elongated tone arm is mounted pivotally intermediate its ends by a gimbal structure in which concentric rings are pivoted at right angles to each other by means of resilient torsion members which allow the tone arm to pivot, substantially without friction, both horizontally and vertically. The outer end of the arm mounts a cartridge stylus and the inner end mounts a longitudinally adjustable counterbalancing weight. Cooperating magnets are mounted on the tone arm and turntable base and are arranged to provide repelling magnetic forces to effect insertion of the stylus in the starting groove of a recorded disc and to effect removal of the stylus from the ending groove of the disc and return of the tone arm to a rest position. Energy absorbing material is contained on the tone arm to prevent the latter from resonating.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.