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Electro-Magnetic Straightening Device and Method of Operation

IP.com Disclosure Number: IPCOM000113665D
Original Publication Date: 1994-Sep-01
Included in the Prior Art Database: 2005-Mar-27
Document File: 4 page(s) / 95K

Publishing Venue

IBM

Related People

Helinski, EF: AUTHOR

Abstract

This is an improved method of adjustment to a magnetic criteria which pertains to stored energy print actuators using permanent magnets. The magnets which attract spring suspended armatures requiring an adjustable balanced force relationship between the spring force and the magnetic force.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 52% of the total text.

Electro-Magnetic Straightening Device and Method of Operation

      This is an improved method of adjustment to a magnetic criteria
which pertains to stored energy print actuators using permanent
magnets.  The magnets which attract spring suspended armatures
requiring an adjustable balanced force relationship between the
spring force and the magnetic force.

      This force balance is difficult to achieve because of
dimensional variations affecting both the spring rate of the flexure
and the cross section of the armature as well as variations in
magnetic characteristics resulting from material composition and heat
treatment.

      Fig. 1 is a side view of a stored energy print actuator having
integrally formed armatures (1) which are attracted to stator poles
(2) by the magnetic flux produced by permanent magnet (3).  The print
hammer has a flexural region (4) which controls the spring rate of
the cantilevered beam like structure.

      The pull-in force is influenced by the magnetic properties of
the beam and any variation in it's geometry especially those
variations which influence its initial position.  The spring rate of
flexure (4) also influences pull in force.  Fig. 2 illustrates the
balance between the spring force and the magnetic force.  The spring
force acts in the opposite direction to the magnetic force and the
spring force characteristic is shown translated to the positive axis
to illustrate the difference in force between the magnetic and spring
force, more particularly the "Pull-in Force".  It can readily be seen
that geometric straightening alone does not result in uniform pull in
force.  This is because of variations in spring rate and cross
sectional armature area variations as well as beam straightness
variations due to tolerances.

      Fig. 3 illustrates the embodiment of the invention applicable
to production tooling where beam holder (11) is fastened to a
mounting fixture (12) which can be positioned on a Z axis to locate
any beam in front of a stator assembly which is accurately positioned
to a reference-location (14) on mounting fixture.  The stator
assembly (10) con...