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US 4,138,121 AGranted
Tone arm assembly
AssigneeSony Corporation
InventorsHeitaro Nakajima, Yoshimoto Omura, Isao Kawashima
Life of this patent
Estimating the term…
Abstract
A tone arm assembly for record players having a first motor for rotating a tone arm in the vertical direction, a second motor for rotating the tone arm in the horizontal direction with respect to a record disc, respectively, a detector for detecting low frequency vertical and horizontal vibrations of the tone arm during the reproduction of a record disc and feeding back an output signal of the detector to the motors so as to cancel the vibrations, whereby high fidelity reproduction of sounds can be performed. Further, the stylus pressure adjustment and elevation angle adjustment of the tone arm are also performed.
Claims23
A tone arm assembly for controlling the tracing of a tone arm across a record disc and for preventing resonance of said tone arm, comprising a tone arm having a cartridge at one end thereof;
- first motor means mechanically coupled to said tone arm for moving said tone arm in the vertical direction with respect to said record disc;
- second motor means mechanically coupled to said tone arm for moving said tone arm in the horizontal direction with respect to said record disc;
- detecting means for detecting low frequency resonance in said tone arm in the vertical and horizontal directions as said tone arm traces said record disc;
- drive means coupled to said first and second motor means for supplying drive signals to said motor means to control the movements of said tone arm;
- and feedback means coupled to said detecting means for feeding back a vertical compensating signal to said drive means so as to compensatingly drive said first motor means in opposition to said detected low frequency resonance and thereby cancel said resonance in the vertical direction in said tone arm, and for feeding back a horizontal compensating signal to said drive means so as to compensatingly drive said second motor means in opposition to said detected low frequency resonance and thereby cancel said resonance in the horizontal direction in said tone arm.
2 more elements
A tone arm assembly comprising:
- a tone arm having a cartridge at one end thereof and movable in vertical and horizontal directions with respect to a record disc;
- a shaft rotated together with the movement of said tone arm in the horizontal direction;
- lever means moved together with said shaft;
- first and second motors provided on said lever means, said first motor serving to move said tone arm in the vertical direction, said second motor serving to move said tone arm in the horizontal direction and comprising a permanent magnet and a coil which is mechanically connected to said lever means and positioned in a magnetic field of said permanent magnet;
- detecting means for detecting low frequency vibrations generated by said tone arm during reproduction of said record disc and for generating output signals in response to said vibrations, said detecting means comprising first and second detectors, said first detector having a first member moved together with said tone arm in the vertical direction and a second member moved together with said shaft, said second detector having a coil mechanically connected to said lever means and a magnetic piece which is connected to said shaft through a mechanical low pass filter, said mechanical low pass filter comprising a spring whose one end is fixed to said shaft and whose other end is fixed to said magnetic piece through an arm lever and feedback means for feeding back said output signals generated by said first and second detectors to control said first and second motors.
2 more elements
A tone arm assembly comprising:
- a tone arm having a cartridge at one end thereof;
- electro-magnet means for moving said tone arm in the vertical and horizontal directions with respect to a record disc, said electro-magnet means comprising a first motor for moving said tone arm in the vertical direction with respect to the record disc and a second motor for moving said tone arm in the horizontal direction with respect to the record disc;
- detecting means for detecting low frequency vibrations generated by said tone arm during reproduction of said record disc and for generating output signals in response to said vibrations, said detecting means comprising a first detector for detecting a low frequency vertical vibration of said tone arm and for generating a first output signal in response to said vertical vibration and a second detector for detecting a low frequency horizontal vibration of said tone arm and for generating a second output signal in response to said horizontal vibration, and each of said first and second motors including a drive circuit, and said first and second output signals being applied to the respective drive circuit so as to cancel each vibration.
A tone arm assembly comprising a tone arm having a cartridge at one end thereof;
- a first motor coupled to said tone arm for moving said tone arm in the vertical direction with respect to a record disc;
- a second motor coupled to said tone arm for moving said tone arm in the horizontal direction with respect to said record disc;
- a first motor drive circuit connected to said first motor;
- a second motor drive circuit connected to said second motor;
- a first detector having a first element fixed in the vertical direction and a second element cooperable with said first element and mechanically coupled to and vertically movable with said tone arm for detecting the vertical position of said tone arm and for generating a corresponding control signal supplied to said first motor drive circuit so as to position said tone arm at a predetermined vertical angle;
- and a second detector having a first element fixed in the horizontal direction and a second element mechanically coupled to said tone arm and movable therewith in said horizontal direction, said last-mentioned first and second elements cooperating with each other to establish lead-in and lead-out sensing positions for detecting the respective lead-in and lead-out positions of said tone arm and for generating a corresponding control signal supplied to said second motor drive circuit so as to control the movement of said tone arm in the horizontal direction.
3 more elements
Dependencies are inferred from the claim text.