Disc-record players

A device for applying, to a phonograph pickup arm mounted on an arm support arranged for joint pivotal movement about a vertical axis relative to a base member, torque about said axis said phonograph pickup arm also being mounted for vertical movement between a playing position and a raised position, said device comprising a permanent magnet means mounted for joint movement with the arm support about said axis and constructed and magnetized to provide two pole faces of opposite polarities, angularly spaced about said axis, both arranged substantially in a common surface of revolution about said vertical axis with each said pole face extending over an angle about said axis at least equal to the angle of operative movement of the pickup arm about said axis with the two pole faces angularly spaced about said axis, said magnetic means being magnetized to produce magnetic flux at right angles to each pole face;

• a winding of conductor wire, mounted to be stationary relative to said base member and having two portions arranged in close proximity to said pole faces, said two portions being arranged for respective electrodynamic co-operation with the flux from each of said pole faces, yoke means of magnetizable material which are mounted for joint movement with said magnet means and arranged to provide a yoke surface facing each said pole surface at such a distance therefrom as to provide a gap sufficient to accommodate said winding portions and form a low-reluctance magnetic circuit for the magnetix flux that extends between each pole face and the yoke surface facing such pole face, the lengths of conductor wire in each said portion extending substantially parallel to said surface of revolution and transversely to the velocity vector of that element of said surface which directly faces the respective portion, said winding portions being electrically connected in series in such manner that when the winding is energized, the electric current flow in each of said winding portions produces, with the magnet flux passing said portion from the magnet means, torque about said axis in the same direction;
• electric circuit means incorporating said winding, switch means forming part of said circuit means and operable, when said circuit means are connected to a suitable source of direct current, to selectively pass, when the pickup arm is in such raised position, motor current from such source through said winding selectively in one or other of two opposite directions and at such strength as to produce, by its electrodynamic co-operation with the flux from the said pole faces, a torque about the said vertical axis in one or other direction according to the selected direction of the current, the device also including damping means for controlling the speed of such movement.