Browse Prior Art Database

Eddy Current Damper

IP.com Disclosure Number: IPCOM000073543D
Original Publication Date: 1971-Jan-01
Included in the Prior Art Database: 2005-Feb-22
Document File: 2 page(s) / 41K

Publishing Venue

IBM

Related People

Sakmann, WH: AUTHOR

Abstract

The speed at which printing can occur is increased by this magnetic damper which controls the settle-out time of the hammers.

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 100% of the total text.

Page 1 of 2

Eddy Current Damper

The speed at which printing can occur is increased by this magnetic damper which controls the settle-out time of the hammers.

Pivoted print hammers 2 are shown at A and B as operated by pushrods 2a, and as moving between pole shoes 4 and 5 of a magnetic core having energizing winding 6. Sides 1 of hammers 2 are copper plated. Hammer guide comb 3 is arranged to provide upper and lower pole shoes 4 and 5. Common coil 6, which provides magnetic flux to all the upper and lower pole shoes, is pulsed during nonprint times to produce eddy currents in the plated surfaces of hammers 2 for damping.

An alternate method of magnet damping of the print hammers is shown at C. The steady flux from generator coil 7 is normally shunted through bypass 10 as shown by the solid lines. To activate the damper, the reluctance of bypass 10 is increased by pulsing bypass coil 8. As shown by the dotted lines, the majority of the total flux now passes through hammer area 9 due to the increased reluctance of the shunt bypass. The use of continuously energized generator coil 7 with a high number of turns serves to reduce the heat. Bypass coil 8 has a low number of turns and hence a low inductance for fast response. The ampere-turns of bypass coil 8 can be much smaller than those of generator coil 7 and yet readily control the flux of such larger generator coil.

1

Page 2 of 2

2

[This page contains 3 pictures or other non-text objects]