Abstract: A head positioning device for positioning a magnetic head of a tape drive wherein the positioning device has a base mounted stationary with respect to a tape circulating past the magnetic head. The positioning device further has a magnet assembly extending upward from the base. The magnet assembly is surrounded by a motor coil which receives electrical current to cause the motor coil to move up and down under influence of the magnet assembly. The device also has a magnet housing substantially enclosing the magnet assembly and the motor coil therein. The magnet housing has a vertical slot arranged on the side of the magnet housing opposite the magnetic head for pass through of a coil holder connected to the coil. Vertical force is transmitted from the coil to the coil holder outside of the magnet housing wherein the coil holder is connected to the magnetic head for vertically positioning the head with respect to the base.

Abstract: A head positioning assembly having a magnet housing and fixed suspension vertically positionable by a worm gear/screw shaft arrangement and further positionable for fine tuning by a magnet mounted within the magnet housing and an electrical coil surrounding the magnet and attached to a head mount structure holding the magnetic head. The head mount structure is fine-tuned, vertically positionable with respect to the magnet housing by magnetic force on the coil induced by select and varying electrical current through the coil.

Abstract: A loud speaker of the oscillating coil type including a voice coil associated with a loud speaker membrane and a magnetic circuit having an annular air gap in which the coil is located in such a manner that in its neutral, non-energized condition the coil projects axially from the air gap substantially uniformly to both sides thereof so as to be able to oscillate substantially symmetrically about the middle plane of the air gap, a cylindric element of an electrically conducting material being rigidly associated with the magnetic circuit concentrically with the coil and extending into the air gap from one side thereof, characterised in that the cylindric element is extended so as to additionally project outwardly from the air gap to the other side thereof. It is obtained hereby that the voice coil is inductively short circuited in all working positions thereof, whereby it responds rapidly to changes of the input voltage and thus causes the sound to be reproduced with a minimum of distortion.