Abstract: A character-carrying disc comprises, arranged on its front face, a circular arc-shaped wire spring ended by two branches, which are rectilinear and bent inwardly constituting a small fork adapted to grip the shaft of a printing machine in which the disc is used and to engage an annular groove of this shaft. This disc carries a slidable pin on a shoulder of which the central portion of the arc-shaped part of the spring bears so as to maintain the pin in an axial position in which it co-operates with a member of the machine to provide a drive connection for rotation of the disc. Thus, the spring performs a double function, ensuring on the one hand the return of the pin to its working position and on the other hand the securing of the disc on the shaft of the machine.

Abstract: A needle-carrying head for a printing machine has needles controlled by electro-magnets. The coils of the electro-magnets are soldered to pins carried by support ears for the coils. The pins pass through printed circuit boards to which they are soldered. The coils are engaged on cores constituted by limbs of respective fork-shaped members the second limb of which serves to complete the magnetic circuit. The two limbs of each fork-shaped member are interconnected by means of a transverse portion constituting a yoke, secured by setting into one or the other of two plates forming, with a central plate made of plastics material, a cage-shaped frame of the needle-carrying head. The printed circuit boards are thus interposed between the electro-magnets and the front plate of the frame on the one hand, and between the electro-magnets and the rear plate on the other hand.

Abstract: A character-carrying disc for a printing machine has a central hole surmounted by a circular portion which is situated out of the plane of a body of the disc and supported at a distance from the body of the disc by two diametrically opposed pillars. This circular portion is provided with two diametrically opposed ears enabling the disc to be gripped. The circular portion of the disc is provided with two small tongues which are elastically deformable and are directed axially, with free ends of the tongues being movable in two openings provided in the body of the disc. The small tongues are adapted to press resiliently on the shaft of the printing machine on which the disc is mounted for the purpose of retaining the disc in place on this shaft.

Abstract: The disc, made of plastic material, is provided with a circular collar coaxial with its central hole and which is provided, diametrically opposed, with two arms bent at 90.degree., each arm terminating with a small tongue the end of which extends beyond the said central hole. These small tongues are intended to engage an annular groove provided in the shaft of the machine at the vicinity of its end. The radial displacements of the small tongues are effected during the deformations of the arms which, due to their elasticity, return the small tongues into position.

Abstract: A character-carrying disc made of plastic material is provided, on its front face, with four protrusions each provided with a circular-arc shaped blade, coaxial with a central mounting hole of the disc. Each blade is itself provided with a projection protruding radially inwardly of the central hole of the disc. These rolls are adapted to engage, by resilient deformation of the blades, in an annular groove provided in the end of a shaft of the machine on which the disc is mounted.

Abstract: A needle-carrying head for a printing machine has needles which are short and rectilinear, the distance separating them being greater than the distance which must separate the printed points produced in the printing operation. Hence, the needles do not have to be bent to enable electro-magnets which drive them to act thereon. The needle-carrying head is mounted in the printing machine in such a way that the plane of the needles is inclined with respect to the writing direction, which compensates for the effect of the distance separating the needles and permits, by appropriate choice of the said inclination, an overlapping of the printed points.

Abstract: A radially displaceable coupling between a printing disc and the drive shaft of a printing machine. A bracket having a planar surface is secured to the drive shaft, the bracket having a planar face. Clamps are provided on one of the disc and bracket faces for engagement with the other of said disc and face. A resilient arm, including a zig-zag configured portion terminating in a blade having an inclined lateral surface, is formed on one of the disc and bracket and a recess is provided in the other of the disc and bracket for receiving the resilient arm to effect securement therein in a wedgelike engagement. A lateral surface borders the recess and coacts with the lateral blade surface. The lateral surfaces are convergent relatively coacting when the arm is engaged within the recess to prevent angular movement of the disc and to cause the disc to bear against the drive shaft at a location diametrically opposite to the location of the recess.

Abstract: A hairpin type spring is mounted on the body of a print wheel disc provided with an upstanding post of generally cylindrical configuration and having an overhang and a pair of second posts spaced longitudinally from the first post. The second posts are each being provided with laterally opening facing recesses defined as ninety degree sectors, each having perpendicular lateral walls. The spring includes a bend and a pair of branch arms. The spring is mounted with its bend bearing on the post beneath the overhang and its arms within the recesses in the second posts bearing laterally against the recess walls with the free ends bearing axially against said recess walls. The first post and the upstanding second posts are formed unitary with the disc.

Abstract: A character-bearing disc operable with a printing machine having a central hub with radially extending flexible arm members, each arm member having a character disposed on an outer portion thereof. The arm members are reinforced at the inner ends thereof by means of longitudinally extending reinforcing ribs, the arm members thus having increased strength at their inner ends without sacrifice of the flexibility necessary to proper function of the disc.

Abstract: A characters carrying aggregate or assembly for a printing machine includes a characters carrying disk carrying the characters on the outer ends of radial arms extending from the disk. The disk is mounted on a hub and may include a crown mounted opposite the hub. The assembly is manufactured on a base plate having at least two positioning pins corresponding to two positioning holes in the disk. The base-plate includes a central hole or protrusion for aligning with a central protrusion or hole in the hub. The base-plate further includes an alignment finger which extends through an orientation hole in the disk into a specific oriented alignment with an orientation hole in the hub. The aligned hub and disk are then secured together.