Abstract: A dot matrix print head wherein each printing device comprises a pin fitted to one end of the anchor of a respective electromagnet. The electromagnet presents an E-shaped core, the center bar of which forms a first pole piece, and the other two bars of which form the other pole piece coplanar with the first. The anchor consists of a plate having a flat surface designed to rest on the first pole piece and defined by two parallel steps. The first step is located on a portion opposite the end fitted with the pin, and rests on the other pole piece. The other step is adjacent to the aforementioned end, and corresponds with the gap between the center bar and a lateral bar of the core, so as to enable overtravel of the plate and the pin for effecting a ballistic print stroke.

Abstract: A dot matrix printing head on which the tips of the printing pins are supported on a matrix, in turn supported on a body designed to travel in the printing plane, in two side by side, parallel offset rows; mainly characterized by the fact that the matrix is supported in idle manner on the supporting body; the printing head presenting means for selectively turning the matrix into two angular positions, in a first of which, the rows of pins are substantially perpendicular to the printing plane for enabling high-definition printing, and in a second of which, both rows of pins are arranged obliquely in relation to the printing plane, and at such an angle that the tips of the pins in both rows are coplanar, thus enabling high-speed printing. (FIGS. 2 and 4).

Abstract: A ballistic type wire printing head comprises a metal front support (11) for guiding the printing wires (23) and supporting a group of actuating electromagnetic units (37, 39, 41) associated with the wires. The armatures (41) of the electromagnetic units are pre-assembled on a disc (40) of plastics material. A rear cover (59) which is also of metal encloses the electromagnetic units and in its interior supports spring spider (58) which co-operates with all the armatures of the electromagnetic units. The electromagnetic units have a common internal, ferromagnetic support (35) from which heat is conducted to the front support (11) and cooling fins (25). In a second embodiment, the printing head also comprises a second group of electromagnetic units associated with another series of printing wires. In that case, an intermediate metal member acts as a cover member for the first group of electromagnetic units and as a support for the second group of electromagnetic units.

Abstract: A striker mechanism for a high speed serial printer, for example of the daisy wheel type, includes a hammer movable axially towards the platen under the action of an electro-magnet whose armature carries a striker, and against the action of a return spring. Two lubricating felt pads are arranged on opposite sides with respect to the striker hammer and are pressed against the hammer by the grip of a spring for damping the hammer vibrations during the printing cycle. The armature comprises a pivoted lever which is damped with respect to its pivot by means of a felt washer and the lever is damped on return by a helical spring on a rod with a reduced diameter center section where it is struck by a pad on the lever.

Abstract: A wire printing head of ballistic type comprises a front guide fixed to a carriage and in which the printing wires are mounted in an axially slidable manner. The electromagnets for actuating the wires have their respective cores mounted inside a tube of non-magnetic material. In order to obtain high heat dissipation, the electromagnet cores and windings are embedded in a resin block which fills the interior of the tube. The exterior of the tube is also provided with a set of cooling fins.The electromagnet armatures are mounted on a rear cover which is connected by a screw to a part of the front guide, which in its turn is housed in a compartment in the resin block. Shims are disposed between the front guide and group of electromagnets, and their number can be varied in order to modify the distance of the ends of the printing wires from the platen.

Abstract: A wire printing device comprises a plurality of printing wires, each one associated with a corresponding driving electromagnet and a frame which is constituted by a plate folded in order to have a central portion, on which are mounted the electromagnets, and a pair of tongues which support guide elements for the printing wires. The gap between armature and core of each electromagnet can be regulated by a screwable element which determines the stroke of the armature and of the associated wire.

Abstract: A hammer assembly for a serial typing device which comprises a character bearing disk having a central hub and a plurality of flexible laminae radiating therefrom each carrying a particular character. The hammer assembly comprises a hammer which is actuatable for selectively causing the lamina of the selected character to strike against a sheet bearing platen for typing. The hammer is directly fixed to the armature of a plunger electromagnet which is energizable with a substantially constant current. The fixed pole pieces of the electromagnet and the armature connected to the hammer have pole surfaces inclined with respect to the longitudinal axis of the hammer, so that the impact force of the hammer varies directly as the energization time of the electromagnet while it remains substantially constant during the entire stroke of the hammer.

Abstract: A wire printing device comprises a plurality of printing wires, each one associated with a corresponding driving electromagnet and a frame which is constituted by a plate folded in order to have a central portion, on which are mounted the electromagnets, and a pair of tongues which support guide elements for the printing wires. The gap between armature and core of each electromagnet can be regulated by a screwable element which determines the stroke of the armature and of the associated wire.