Abstract: The MRI apparatus includes an actively shielded gradient system (40) with primary gradient coils and shielding coils (56). Despite the active shielding, such a system inevitably causes a magnetic field to some extent outside the shielding, so that eddy currents are generated in the conductive structures of the main magnet, said eddy currents causing heat dissipation and annoying noise. According to the invention, the gradient system also includes an eddy current shield (48) which consists of an electrically conductive, substantially closed plate; furthermore, the primary gradient coil (60) and the shielding coil (56) are arranged within the eddy current shield (48) and these three elements together constitute a mechanically rigid unit. As a result, eddy currents are avoided in the main magnet and annoying noise is strongly reduced.

Abstract: An apparatus having a read/write head for reading and/or writing information on an information carrier which may be in the form of a tape or disc. The head is mounted on a drum which is supported on a shaft which axially rotates the drum so as to move the head relative to the information carrier, which in the case of a tape winds around the drum. The drum is supported in the axial direction by a thrust bearing and in the radial direction by fluid bearings (25) and (26). The thrust bearing has adjoining surfaces of which at least one is made of cemented tungsten carbine, the other possibly being of steel. Thus, there is low friction and low wear. During operation of the apparatus the bearing surfaces remain in contact, thereby forming an electrical coupling to a grounding frame of the apparatus so as to limit static charging of the rotating drum.

Abstract: Deflection unit for a display tube, comprising a coil support (8) with a saddle-type field deflection coil (12) and a yoke ring (14) surrounding this coil. A form-filling adhesive material (extending between the open portions of the field deflection coil as far as the support) is provided in the free space between the support (8) and the yoke ring (14), with which material the support and the field deflection coil are rigidly connected to the inner surface of the yoke ring. Vibrations of the yoke ring, and noise generated by the coil support due to transmission of these vibrations to the support, are substantially prevented, particularly if the adhesive material also has a damping effect, or if a thin layer of visco-elastic material preferably realizing a detachable connection between the adhesive material and the yoke ring is provided between this adhesive material and the yoke ring.

Abstract: A method of manufacturing magnetic head cores is provided in which a plurality of separate magnetic head cores is cut from a one-piece ferrite core block. A winding aperture is provided in each magnetic head core. A fracture in the cross-section of the material of the head core is generated by the winding aperture and the future tape contact face during or after the winding aperture is provided. A non-magnetic material in a liquid form is provided between the fracture faces and is converted to the solid form.

Abstract: A magnetic head (1) includes a core of a magnetic material having two parts (2, 3) spaced apart from each other to form a non-magnetic transducing gap (4) which is bounded on one side by a winding aperture (5) extending in the gap-bounding surface of at least one of the core parts and narrowing towards the transducing gap. To produce an accurate gap dimension the part of the winding aperture (5) immediately adjoining the transducing gap (4) is formed by a channel (6, 13, 20, 21, 32, 33) of a defined depth. The channel is formed in the gap-bounding surface of the core parts by means of an etching process. During the etching of the channels polishing marks may be simultaneously produced, the polishing marks serving as guides for subsequent grinding/polishing stages in the production of the magnetic head.

Abstract: Magnetic core, suitable for use in a magnetic head or in a transformer. The magnetic core is composed of lamellar core parts of amorphous, ferromagnetic material coated with a thin film of an oxidic material chosen from the group comprising SiO.sub.2, Al.sub.2 O.sub.3, TiO.sub.2 and Si.sub.3 N.sub.4. The core parts are bonded together by means of an epoxy adhesive.