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Print Hammer Unit

IP.com Disclosure Number: IPCOM000077515D
Original Publication Date: 1972-Aug-01
Included in the Prior Art Database: 2005-Feb-25
Document File: 2 page(s) / 55K

Publishing Venue

IBM

Related People

McCarty, VD: AUTHOR

Abstract

This print hammer unit lends itself to high energy and high repetition rate applications, providing a long life with a high-duty cycle and relatively small type spacing.

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Print Hammer Unit

This print hammer unit lends itself to high energy and high repetition rate applications, providing a long life with a high-duty cycle and relatively small type spacing.

A magnetic yoke structure 1 is energized by a holding coil 3, the yoke and holding coil being common to all of the hammers in the unit. The magnetic circuit is subdivided and a branch thereof along with a separate bucking coil 5 is provided for each of the individual hammers. Each hammer unit comprises an armature element 7, welded or otherwise affixed to the hammer structure 9, which bears a type element 11 that is either engraved or otherwise formed as an integral portion of the element 9, or is a type slug which is welded in place.

Alternatively, the hammer could have a flat face with either fixed or movable type on the opposite side of the paper.

Two flexural elements 15 and 17 serve to support the hammer and to provide the force to propel the hammer. The force, and hence the flight time, can be adjusted by changing the amount of interference between the fulcrum 13 and the flexural element 15. A screw 23 is provided to adjust the amount of interference. As an alternate approach, the fulcrum could be replaced with a flat spring which is long enough to contact the hammer 9 near the armature 7. The hammer is normally drawn against the fulcrum and away from the platen 19 and paper 21, by the energy exerted by the holding coil 3. To fire the hammer, bucking coil 5 is energized, w...