Disc record player

Claim 2

A disc record player including a pickup arm for tracking a disc record, said record player comprising feedback means responsive to at least one of velocity and acceleration of the pickup arm for producing a motor control signal, and means including a linear type electric actuating motor responsive to said motor control signal for causing said pickup arm to tangentially track said record.

Claim 3

A disc record player as claimed in claim 1 in which the feedback means is responsive to both said velocity and acceleration of said pickup arm to provide the motor control signal.

Claim 4

A disc record player as claimed in claim 1 in which the feed back means for providing the motor control comprises electrical position responsive means for providing a signal representative of a position of the pick up arm and differentiation means for differentiating the signal provided by the position responsive means.

Claim 5

A disc record player as claimed in claim 3 in which the electrical position responsive means is a wiper movable along a resistive track.

Claim 6

A disc record player as claimed in claim 1 in which the motor comprises movable coil means for moving along a path adjacent strip magnet means arranged between opposed magnetisable members which are magnetically linked at least part of the coil means being disposed between the strip magnet means and one of the magnetisable members so that when energised relative movement between the coil means and the strip magnet means is obtained.

Claim 7

A disc record player as claimed in claim 5 in which the strip magnet means has similarly poled ends and the coil means includes at least one turn arranged around one of the members.

Claim 8

A disc record player as claimed in claim 5 in which the strip magnet means is magnetic rubber strip.

Claim 9

A disc record player as claimed in claim 5 in which the coil means is carried by a movable carriage upon which the pick up arm is mounted.

Claim 10

A disc record player as claimed in claim 8 in which the movable carriage is provided with wheels which run on guide rods.

Claim 11

A disc record player as claimed in claim 9 in which at least one wheel has a grooved rim which engages a respective guide rod.

Claim 12

A disc record player as claimed in claim 9 in which each wheel has a central axle which is supported by a pair of bearing members each having a generally V-shaped cut out portion to accommodate the axle.

Claim 13

A disc record player including a pickup arm for tracking a disc record, said record player comprising feedback means, responsive to at least one of the velocity or acceleration of said pickup arm, for producing a motor control signal, and means including a linear type electric motor, responsive to said motor control signal, for causing said pickup arm to tangentially track said record, the motor comprising a pair of opposed magnetizable members which are magnetically linked, a strip magnet arranged between the members and carried by one of them, said magnet having opposite ends of the same polarity, coil means provided around one of the opposed members, a wheeled carriage arranged to bridge the pair of members and to carry upon opposite surface portions the coil means and the pickup arm, a pair of wheels mounted on the carriage and having grooved rims arranged to engage a first guide rod positioned to one side of the pair of members, a third wheel mounted on the carriage opposed to the pair of wheels and arranged to run along a second guide rod positioned to a side of the pair of members opposite to the said one side.

Claim 14

A disc record player including a pickup arm for tracking a disc record, said record player comprising feedback means, responsive to at least one of the velocity or acceleration of said pickup arm, for producing a motor control signal, and means including a linear type electric motor, responsive to said motor control signal, for causing said pickup arm to tangentially track said record, the motor comprising a pair of opposed magnetizable members which are magnetically linked, a strip magnet arranged between the members and carried by one of them, said magnet having opposite ends of the same polarity, coil means provided around one of the opposed members, a wheeled carriage arranged to bridge the pair of members and to carry upon opposite surface portions the coil means and the pickup arm, a pair of wheels mounted on the carriage and having grooved rims arranged to engage a first guide rod positioned to one side of the pair of members, a third wheel mounted on the carriage opposed to the pair of wheels and arranged to run along a second guide rod positioned to a side of the pair of members opposite to the said one side.

Claim 15

A disc record player as claimed in claim 12 in which each of said pair of wheels and the said third wheel has a central axle supported by a pair of bearing members each having a V-shaped cut out portion to accommodate the axle.

Claim 16

A disc record player as claimed in claim 12 in which the feed back means includes potentiometer means formed by a resistive track positioned substantially parallel to the first and second guide rods and a wiper extending from the carriage to contact the track, the potentiometer means providing a signal representative of the position of the carriage and there is provided differentiation means for differentiating the said signal.