International Business Machines Corporation

William A Patterson

William D Thorne

Douglas Stuart Brown

James R Wooden

Dien H Tong

This invention relates to printing elements for use in a serial wire matrix printer having a plurality of driven wire printing elements. Each printing element has actuating means associated therewith to drive the elements against a ribbon from a retracted position to an actuated position and returned. Each actuating means includes an elongated drive element anchored at opposite ends thereof to piezoelectric crystal stacks. The piezoelectric stacks have electrical supply means for causing expansion of the crystal stacks responsive to an electric signal. The drive element is normally maintained in a taut bowed position and is secured to the piezoelectric crystal stacks so as to be driven toward a straightened condition upon actuation to the piezoelectrical crystal stacks to thereby drive the printing element axially to the printing or actuated position from the retracted position upon actuation of the crystal assembly. Spring biasing means are provided which coact with the printing element to return the printing element to its retracted position when the electrical signal is removed or reversed in polarity.

Taut band piezoelectric actuator for wire matrix printing elements

The present invention relates to an assembly of electromagnetic actuators for the hammers of an impact printer arranged side by side and extending along a line. Each actuator comprises a first stator part formed with at least one pole piece, a second stator part formed with at least one pole piece and positioned relative to the first stator part so that the pole pieces are spaced apart so as to form a gap therebetween. A single coil is associated with one of the stator parts. Each actuator also includes an armature member formed with a body of non-magnetizable material, at least one armature element of magnetizable material and a hammer head. The armature member is supported between the stator parts so that the armature element is located adjacent to the gap. Energization of the coil causes the generation of a flux which passes across the gap and through the armature element tending to move the armature element into the gap and to cause the hammer head to move into a print position. According to the invention the components of adjacent actuators are complementary in shape so that projecting components of each actuator engage in recessed components of the adjacent actuators whereby the overall length of the assembly along the line is less than the sum of the overall widths of the individual actuators.

Electromagnetic hammer actuator for impact printer

An improved print hammer and actuator mechanism therefor are described. The hammer mechanism comprises a solenoid plunger and push wire or push rod which is directly affixed to one end of the hammer. The opposite end of the hammer is flexibly or pivotably mounted by a spring. The spring is rigidly affixed to the bottom portion of the hammer. It is flexed or twisted to enable the hammer top portion to be deflected. A shock absorbing connector connects the push wire to the print hammer. The position of the solenoid plunger can be adjusted by adjustable abutments at either end of its throw. This adjusts the flight time and the impact force, as well as the relative rest position of the hammer face, since the push wire is firmly connected to both the plunger and to the top of the hammer mechanism. The shock absorbing connector between the end of the push wire and the hammer mechanism controls the amount of force applied at impact.

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Charlotte, NC, United States of America

William A Patterson