US 3,982,622 A · Actuator mechanisms for wire matrix printers

Abstract

A wire matrix printer includes a print head having one or more banks of a plurality of generally horizontal, vertically spaced print wires arranged parallel to each other for linear reciprocation toward and away from a recording surface by associated actuators. The print wires in each bank are of progressively varying length so that the wire associated with the actuator furthest from the recording surface is the longest and each adjacent wire is a predetermined amount shorter than the preceding wire. Outer or actuator ends of the wires define a vertically spaced and stepped array. The actuators in each bank are also in an array vertically spaced and stepped and are respectively coupled to the outer print wire ends by armatures. The inner or printing ends of the wires define a vertically spaced, nearly planar array near the recording surface, and a spaced, planar array at such surface. If there is more than one bank of print wires, the banks are angularly spaced from a line extending perpendicularly from the recording surface, and the inner ends of the wires in each bank are alternately interleaved near the recording surface. The actuators in each bank include the armatures, as well as torsion springs, a pair of pole pieces, a permanent magnet and an electrical coil. The armatures are mounted to the pole pieces by both the torsion member and the magnetic attraction of the permanent magnet for generally horizontal, pivoting movement. The pole pieces are magnetized by the permanent magnet to normally attract and hold each armature adjacent thereto against the action of its associated torsion spring thereby storing potential energy therein. The flux of the permanent magnet is selectively counteracted, or neutralized or cancelled for a selected armature by energization of its associated coil to rotate the armature on and about one of its pole pieces for impacting the inner end of the print wire coupled thereto against the recording surface due to conversion of the potential energy stored in the torsion spring to kinetic energy of the armature. Further details relate to the positioning and geometry of the print wires, the armatures, the pole pieces, the permanent magnets, and the coils in certain environments, such as in print heads of a wire matrix printers.

Claims41

Dependent claims

In a wire matrix printer, an actuator for selectively impacting an end of a print wire on a recording medium, comprising:

a. an armature of ferromagnetic material having an elongated body to which the print wire is mounted at a first end thereof, the armature being rotatable in a circular arc about an axis of rotation adjacent to a second end thereof and perpendicular to the body, for moving the print wire end toward and away from the recording medium;
b. a rotatable torsion rod attached to the second end of the armature and extending parallel to the axis of rotation of the armature, the armature assuming a neutral position when the torsion rod is free of torsional stress;
c. means for normally magnetically attracting the armature to a rest position by rotating the armature on the axis away from the neutral position to move the wire end away from the recording medium and to twist the torsion rod to torsionally stress the torsion rod;
and
d. means for neutralizing the magnetic attraction so that the torsionally stressed rod rotates the armature toward the neutral position to drive the print wire end toward the recording medium for impacting the wire end

2 more elements

In a matrix printer, an actuator for selectively impacting an end of a print wire on a recording medium, comprising:

a. an armature to which the print wire is mounted, the armature being pivotable about an axis for moving the print wire end toward and away from the recording medium;
b. a torsion spring attached to the armature, the armature assuming a neutral position when the spring is free of torsional stress;
c. means for normally magnetically attracting the armature to a rest position by pivoting the armature on the axis away from the neutral position to move the wire end away from the recording medium and to torsionally stress the spring;
d. means for neutralizing the magnetic attraction thus permitting the torsionally stressed spring to pivot the armature toward the neutral position and to move the wire end toward the recording medium for impacting the wire end thereon;
e. means for momentarily energizing the neutralizing means to impact the wire end on the recording medium, deenergization of the neutralizing means permitting the attracting means to return the armature to the rest position;
and
f. means for mounting the wire to the armature to impact the wire end on the recording medium as the armature reaches the neutral position upon energization of the neutralizing means;
the neutralizing means comprising (d.sub.1) an electrical coil positioned about and surrounding, but not mechanically loading, the armature which is

5 more elements

An improved print wire-actuator bank for a matrix print head of a matrix printer of the type in which:

a. the ends of a plurality of elongated print wires are respectively, selectively impacted by a plurality of actuators against a record medium in a matrix;
b. the print wires and their respective actuators are mounted to the head which is traversed across the medium to print lines of alpha-numeric characters thereon in accordance with the selective wire end impaction;
c. each actuator includes a movable armature for moving an associated wire therewith, each armature being attracted to a first position by associated magnet means against the action of an associated resilient member, thereby storing in the member potential energy biasing each armature toward a second position, each wire end impacting on the medium only at the second armature position, and means associated with each armature for selectively, momentarily neutralizing the magnetic attraction of the magnet means for that armature to permit the stored energy of such armature's resilient member to move the armature from the first to second position and to impact the end of its print wire against the medium, wherein the improvement comprises:
I. the resilient members are torsion springs on which each armature is respectively mounted for rotation on a rotational axis of the armature and about a torsional axis of the spring;
Ii. each neutralizing means comprises an electric coil surrounding but not mechanically loading its respective armature;
Iii. the magnet means associated with each armature comprises;
a pair of pole pieces both of which contact the armature in its first position, a first one of which pole pieces coincides with the rotational axis of, and remains in contact with, the armature during its movement to the second position, a second one of which pole pieces becomes spaced from the armature in its second position;
and
a permanent magnet, opposite poles of which are respectively adjacent the pole pieces;
Iv. each print wire includes a U-shaped loop remote from the print end thereof;
V. each armature includes a portion contained within the U-shaped loop and engaged by the legs thereof;
and
wherein the improvement further comprises:
Vi. a first ferromagnetic plate attached to all of the first pole pieces and contacting one pole of the magnet;
Vii. a second ferromagnetic plate attached to all of the second pole pieces and contacting the other pole of the magnet;
Viii. means on each torsion spring for respectively mounting each spring to the first and second plates, the spring mounting means including:
an arm fixed to the spring;
and
means for applying flux from the magnet to the arm to maintain the arm stationary during armature movement;
and
Ix. guide means for ensuring movement of the wires toward the medium along the major axes thereof and for preventing bending of the wires during impact, the guide means including:
a plurality of guide members spaced along the wires and having apertures therethrough for receiving and periodically supporting the wires;
and
a guide block having a channel therein for receiving the U-shaped loops to prevent rotation and movement of the wires in directions transverse to

21 more elements

Dependencies are inferred from the claim text.

Actuator mechanisms for wire matrix printers

Life of this patent

Actuator mechanisms for wire matrix printers

Life of this patent

Abstract

Claims41