Abstract: The invention relates to denture-supporting permanent magnet assemblies each using a magnetic attractive force, and provides denture-supporting permanent magnet assemblies, denture-supporting keepers, and denture-supporting magnetic attachments each of which uses a magnetic material with a high saturation magnetic flux density, i.e., a magnetic material comprising 15.5-18.5 wt % Cr and balance Fe as magnetic materials used for the permanent magnet assembly and the keeper in order to provide a magnetic attachment which keeps an excellent attractive force even if miniaturized.

Abstract: A permanent magnet assembly for stably fixing a denture comprising a permanent magnet, a casing made of a corrosion-resistant, magnetic material having a cavity for receiving the permanent magnet, and a seal plate for covering an opening of the casing to prevent the permanent magnet from exposing outside, the seal plate consisting of a seal ring member made of a corrosion-resistant, non-magnetic material and a disc plate made of a corrosion-resistant, soft-magnetic material and having substantially the same outer diameter as the inner diameter of the seal ring member, the seal ring member and the disc plate being concentrically arranged in the same plane, the disc plate being welded to the seal ring member in their abutment, and the seal ring member being welded to the casing. Laser welding is utilized.

Abstract: A wire dot printer head comprising a leaf spring welded to an armature and biased by a permanent magnet, and a magnetic coil adapted to erase the magnetic field of the permanent magnet so as to release the leaf spring and to drive a print wire. The leaf spring is made of an alloy which consists essentially of 13-14 wt % Cr, 0.37-0.43 wt % C, 0.25-0.5 wt % Si, 0.3-0.5 wt % Mn, 1.15-1.35 wt % Mo and the balance Fe. The alloy makes the width of the weld metal of the leaf spring wide and its depth of weld penetration deep and thus minimizes the generation of micro-cracking.

Abstract: A magnetic direction sensor having a head constituted by a magnetic wound core composed of a ferromagnetic metal ribbon; a winding for exciting the magnetic wound core; a first output winding wound around the core such that it encircles two opposite portions of the core and a second output winding wound around the core at a certain angle with the first output winding such that it encircles two other opposite portions of the core; the first and second output windings providing output signals for determining the direction of the external magnetic field with respect to the head, and the inner and outer ends of the ribbon overlapping each other circumferentially by a certain angle .theta. may be between 0.5 and .theta..sub.max satisfying the equation: .theta..sub.max =1/4D+1.5.alpha.+1 wherein D represents the outer diameter of the core and .theta. represents a desired direction accuracy. This structure of the sensor head enables it to obtain a high direction accuracy.