Browse Prior Art Database

Magnet Armature Noise Control

IP.com Disclosure Number: IPCOM000119978D
Original Publication Date: 1991-Mar-01
Included in the Prior Art Database: 2005-Apr-02
Document File: 2 page(s) / 48K

Publishing Venue

IBM

Related People

Hughes, FM: AUTHOR [+2]

Abstract

Disclosed is a design that reduces the impact noise of the armature of an electro-magnet such as is used to control the motion of the "D-roller" used on the 4019 printer. At least two types of impacts can exist when operating the magnet: When the magnet seals during actuation When the D-roller gear completes its rotation, a ledge on it hits the armature axially

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Magnet Armature Noise Control

      Disclosed is a design that reduces the impact noise of
the armature of an electro-magnet such as is used to control the
motion of the "D-roller" used on the 4019 printer.  At least two
types of impacts can exist when operating the magnet:
         When the magnet seals during actuation
         When the D-roller gear completes its rotation, a
         ledge on it hits the armature axially

      Magnet 1 serves to control the motion of the "D-roller" gear 3
used on the 4019 printer.  When not active, gear 3 is at rest,
prevented from rotating by armature 2 at the detent edge 7 on the
gear.  When a sheet of paper is to be launched from the paper drawer,
magnet 1 is energized for approximately 35 milliseconds so that the
armature moves away from edge 7 allowing spring 4 to accelerate the
gear clockwise.  The motion of the armature tends to close gap 6.  A
piece 8 made from closed cell polyolefin foam prevents metal to metal
contact between armature 2 and yoke 9.  This effect is the most
important sound reduction measure of this design.

      When the D-roller gear 3 comes to the end of one revolution, it
again accelerates due to leaf spring 4, causing edge 7 to impact the
corresponding edge on the armature.  This impact then reverses the
backlash existing between notch 5 of the armature and bracket 10.
The sound of this impact is muffled by insert molding the metal
armature in plastic.  The heavy...