Abstract: This invention relates to a coil unit of coreless armatures. Inner and outer cylindrical coils formed of parallelly arranged coil element wires of an equal length are fitted and combined with each other and overlapping parts thereof are joined sequentially to form electrically closed loops. The thickness in the radial direction of the coil unit is made uniform by means of the foregoing formation. Also, as the length per turn of the coil element wires becomes uniform, a coil unit excellent in the dynamic balance can be obtained and, further, the shape of the cross-section of the coil element wires can be made proper with the cross-sectional area made constant, so that motors of different numbers of turns can be easily designed.

Abstract: Actuation of a prefatiguing lamp is selectively controlled in accordance with the measured time interval between successive copying operations. In substantially continuous copying where the measured interval is less than a first predetermined time period, no prefatiguing illumination is provided. Where the measured interval exceeds a second, longer predetermined time period, full illumination is provided. When the measured interval is between the first and second predetermined periods, partial illumination is provided by appropriate reduction in the operating voltage impressed upon the prefatiguing lamp.

Abstract: A method of making cylindrical rotor coil for use in coreless motors is provided whereby the coil is of a reduced thickness with compressed coil turns enabling the stator magnetic gap distance to be reduced, thus enabling a higher flux density to be utilized highly efficiently in the gap. A radially inward force is applied to a cylindrically wound coil of an insulation coated wire so as to act against the outer periphery of the cylindrical coil, whereby respective turns of the wire are compressed together and flattened on their portions defining the respective peripheries. The force application is preferably repeated while varying the relative position of the cylindrical coil in its peripheral directions to the applied force. A mandrel is inserted into the coil before the coil is compressed. The outer diameter of the mandrel is less than the inner diameter of the coil so that the inner and outer diameters of the coil is compressed radially inwardly against the mandrel.

Abstract: A cylindrically-shaped multilayered coil structure comprises a plurality of diagonally wound coil sections extending circumferentially around the coil. Each section includes inner and outer layers. Each such layer includes initial and final turns. During winding of the coil, after the final turn of an inner layer is wound, the coil wire is wound to form a crossing part which extends back to the initial turn of the inner layer of that same section. Winding of the outer layer of that section is then performed. Subsequent coil sections are wound in a similar manner. The crossing parts are sandwiched between the respective inner and outer layers and comprise continuous unbroken sections of the coil wire.

Abstract: An improved method of manufacturing coreless armatures typically for coreless motors, according to which a coreless cylindrical coil and an insulative disk member carrying commutator segments and rotary shaft are mechanically strongly coupled together without any adhesive agent, is provided. A radially inward compressive force is applied to the outer periphery of the coil within which the disk member is inserted at position for the coupling until coil windings partly bulge inwardly to clamp the peripheral edge of the disk member whereas a substantial part of the windings is compressed dense and into a smooth cylindrical shape.

Abstract: A method of making cylindrical rotor coil for use in coreless motors is provided whereby the coil is of a reduced thickness with compressed coil turns enabling the stator magnetic gap distance to be reduced, thus enabling a higher flux density to be utilized highly efficiently in the gap. A force is applied to a cylindrically wound coil of an insulation coated wire so as to act in its radial directions and against at least one of the inner and outer peripheries of the cylindrical coil, whereby respective turns of the wire are compressed together and flattened on the plane defining the respective peripheries. The force application is preferably repeated while varying the relative position of the cylindrical coil in its peripheral directions to the applied force.

Abstract: A method of fabricating cylindrical rotor coil for use in coreless motors is provided, wherein coated insulation film on coil wire at a plurality of positions to be located at an axial end edge of the rotor coil cylindrically wound is removed for connection with commutator segments during winding operation of the wire into cylindrical shape. The winding operation is preferably intermittently interrupted for performing the insulation film removal. Advantageously, the removal is performed by dipping the particular positions into a molten state solder, whereby the film is thermally fused and removed and exposed conductor parts are simultaneously coated with the solder. The film may be removed, alternatively, by means of high frequency induction heat or high voltage discharge arc.

Abstract: A method of making outer blades for electric shavers wherein a metal sheet in which many hair inlet holes are made by punching or coining process is subjected to grinding process performed on the side at which the blade is to engage inner blade of the shaver and then to pressing process with a soft ram pressed against a rigid body on which the sheet is placed, so that any grinding fins remaining on peripheral edges of the respective holes will be thereby removed.