Abstract: An induction heating device for surface treating the teeth (11) of a mechanical part on which each tooth (111) has a projecting tip (111s) and a tooth root linking the tooth to an adjacent tooth, wherein an in duction coil (12, 12') is spaced from the tooth tips and powered by at least one high-frequency current source. The coil consists of a set of conductive segments (24, 24') individually orthogonal to the generatrix (d, d') of the teeth, located above respective tooth tips and interconnected via connecting segments (25, 25').

Abstract: The apparatus is used for writing on and/or reading two magnetic discs of flexible type each one contained for rotation in a protective cover provided with transducer apertures. The apparatus comprises two insertion devices on which the protective covers of the discs are inserted in manner that the discs lie substantially in two parallel planes, having the corresponding magnetizable surfaces oppositely faced therebetween. The insertion devices through corresponding counter-mandrels, causes the discs to engage a pair of driving mandrels for the rotation of the two discs. The driving mandrels and the discs are rotated in opposite senses and, between the two discs, are disposed two transducers which are jointly positioned with respect to the magnetizable surfaces of the discs along the transducer apertures.