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Inventor

Douglas J. Hennenfent

Inventor
Minneapolis, MN, US

Overview

15→
Patents
1976–1996
Patent span
Performing operations
Primary field (CPC B)

Patents· 15 as inventor

Public. Assignee & technology derived from the patent record. Each patent links to its LexDana page.

G11Bprimary
G11BInformation storage based on relative movement between record carrier and transducer25%
Y10TTechnical subjects covered by former us classification25%
B23QDetails, components, or accessories for machine tools, e.g. arrangements for copying or controlling9%
B23PMetal-working not otherwise provided for6%
B24DTools for grinding, buffing or sharpening6%
B25BTools or bench devices not otherwise provided for, for fastening, connecting, disengaging, or holding6%
Y10STechnical subjects covered by former uspc cross-reference art collections [xracs] and digests6%
B02CCrushing, pulverising, or disintegrating in general3%
B23DPlaning3%
B24BMachines, devices, or processes for grinding or polishing3%
PatentTitleYear
5,580,006'Sprocket crusher'19964,942,658'Method for manufacturing a magnetic head core with a flux gap having a precisely controlled length'19904,874,922'Granule vise for manufacturing a magnetic head core with a glass fillet adjacent the inner edge of the gap'19894,559,743'Method for calibrating a machining sensor'19854,536,992'Precision lapping system'19854,517,041'Method for attaching a workpiece to a workpiece carrier'19854,457,114'Workpiece carrier'19844,297,781'Method of aligning a precision grinding wheel assembly'19814,279,102'Method of manufacturing narrow track ferrite head cores'19814,236,355'Precision grinding wheel mount'19804,182,643'Method of forming gaps in magnetic heads'19804,006,525'Method of machining vise jaw face'19773,986,209'Magnetic read head with offset flux gaps'19763,982,318'Magnetic transducer head core manufacturing method'19763,951,395'Resilient vise jaw'1976

Career & activity timeline

Assembled from patent assignee/location history and declaration credentials.

1976–1980Patents assigned to CONTROL DATA CORP (6)· patent assignee history
1976–1990Based in Minneapolis, MN, US· patent location history
1981–1990Patents assigned to MAGNETIC PERIPHERALS INC (6)· patent assignee history
1984–1996Based in New Hope, MN, US· patent location history
1985Patents assigned to MAGNETIC PERIPHERALS (1)· patent assignee history
1989Patents assigned to IMPRIS TECHNOLOGY INC (1)· patent assignee history
1996Patents assigned to RECYCLIGHTS INC (1)· patent assignee history

Inventor activity

Assignee and location history derived from the patent record.

Assignees
AssigneePatentsSpan
CONTROL DATA CORP61976–1980
MAGNETIC PERIPHERALS INC61981–1990
IMPRIS TECHNOLOGY INC11989
MAGNETIC PERIPHERALS11985
RECYCLIGHTS INC11996
Locations
LocationPatentsSpan
Minneapolis, Minnesota, US101976–1990
New Hope, Minnesota, US51984–1996