Track skipper for a video disc player

In a system for recovering prerecorded information from a disc record having a spiral information track by a track-following stylus when stylus/record relative velocity is established;

• wherein normal operation of said system involves sensing of said prerecorded information along successive convolutions of said spiral track in a regular progression toward one extremity;
• a combination comprising:
• (A) a stylus arm having a longitudinal axis and carrying said track-following stylus at one end thereof;
• (B) means for yieldably supporting the end of said stylus arm remote from said one end;
• (C) selectively actuated means for twisting said stylus arm about said longitudial axis thereof to cause a shift in the radial location of said track-following stylus;
• said selectively actuated twisting means including a permanent magnet secured to said stylus arm adjacent to said remote end thereof and an electromagnet for providing a controllable magnetic field of a given polarity when energized;
• said electromagnet being located such that an interaction can take place between said permanent magnet and said controllable magnetic filed;
• wherein said securing of said permanent magnet to said stylus arm is such that said energization causes said twisting of said stylus arm about said longitudinal axis thereof to effect said radial shift in the location of said track-following stylus;
• (D) means for developing an error signal indicative of a disruption in said regular progression by an undesired shift in the radial location of said track-following stylus;
• (E) means, responsive to the development of said error signal, for selectively actuating said selectively actuated twisting means to cause a shift in the radial location of said track-following stylus in a manner that offsets said disruption of said regular progression;
• said selectively acutating means including means responsive to the development of said error signal of a given sense and an amplitude exceeding a given threshold for developing a standard correction pulse for application to said electromagnet;
• and
• (F) means responsive to said error signal for substantially restraining said one end of said stylus arm in a direction radially disposed relative to said disc record, while allowing said twisting of said stylus arm about said longitudinal axis thereof.

A pickup cartridge comprising:

• (A) a cartridge body;
• (B) a stylus;
• (C) a stylus arm having a longitudinal axis and carrying said stylus at one end thereof;
• (D) means for yieldably supporting the end of said stylus arm remote from said one end in said cartridge body;
• (E) means for selectively retaining said stylus arm within the confines of said cartridge body;
• (F) said cartridge body having an opening near said one end of said stylus arm for allowing said stylus to protrude therethrough for playback;
• p1 (G) a first permanent magnet having an axis and secured to said stylus arm near said remote end thereof;
• and
• (H) a second permanent magnet also having an axis and secured to said stylus arm near said one end thereof such that said axes of said permanent magnets are mutually orthogonal.