Setting mechanism for the pickup head of a disc storage system, especially for teaching purposes

Claim 1

In a disc storage apparatus for recording or reproducing electric signals from a disc carrying said signals in a spiral track, said storage apparatus having a recording or reproducing head mounted on a support for radial movement in selective contact with a revolution of the track on said recording disc, a turntable upon which the disc may be placed and a drive means for rotating said turntable and said disc, the improvement which comprises: a spindle threaded along its length and rotatably mounted adjacent to said turntable, said threaded spindle having a thread pitch equal to the distance between two revolutions at the track on the disc; rotation transmitting means interposed between the drive means and said threaded spindle for simultaneously and synchronously rotating the turntable and said threaded spindle; a threaded guide element arranged on said head support for engagement with said threaded spindle; a guide means arranged parallel to the threaded spindle whereon the recording head support is translationally and pivotally mounted, said translational movement being along the axis of said guide means, said pivotal movement being about the axis of said guide means, said pivotal movement resulting in the disengaging of said threaded guide element and simultaneously moving the head out of contact with the disc; a rack on the recording head support, said rack being arranged parallel to said guide means, said rack having teeth of a given size and pitch; a pinion having teeth of said given size and pitch carried by an actuating member, said pinion being arranged for continuous engagement with said rack, said actuating member being connected to the recording head support and being manually operable in two different modes, in the first of said modes the turning of said actuating member effecting rotational movement of the pinion and lateral movement of the rack and head support, while the said movement is guided via the said threaded guide element which cooperates with the said threaded spindle and thereby ensures a movement of the head for selectively accurate contact with a desired one of the tracks and in the second of said modes the depressing and subsequent turning of said actuating member pivoting the support to move the head out of contact with the disc and simultaneously disengaging the threaded guide element from the threaded spindle for free lateral movement of the rack and head support upon turning of said actuating member.