Inventor

John D. Campbell

Inventor

Rochester Hills, MI, US

Overview

1977–2019

Patent span

Electricity

Primary field (CPC H)

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

H02Kprimary

H02KDynamo-electric machines33%

Y10TTechnical subjects covered by former us classification25%

B64DEquipment for fitting in or to aircraft8%

F04DNon-positive-displacement pumps8%

G01RMeasuring electric variables8%

LOC088%

LOCD08%

PatentTitleYear

Assembled from patent assignee/location history and declaration credentials.

1977–2013Patents assigned to CAMPBELL JOHN D (3)· patent assignee history

1977Based in Los Angeles, CA, US· patent location history

1980Patents assigned to ALLIS CHALMERS (1)· patent assignee history

1980Based in Northport, NY, US· patent location history

1980Based in Cincinnati, OH, US· patent location history

2013Patents assigned to GM GLOBAL TECH OPERATIONS INC (2)· patent assignee history

2013Patents assigned to RHOADS FREDERICK W (2)· patent assignee history

2013–2019Based in Rochester Hills, MI, US· patent location history

2015Based in Muncie, IN, US· patent location history

2016–2019Patents assigned to GM GLOBAL TECH OPERATIONS LLC (2)· patent assignee history

Assignee and location history derived from the patent record.

Assignees

Assignee	Patents	Span
CAMPBELL JOHN Dself	3	1977–2013
GM GLOBAL TECH OPERATIONS INC	2	2013
GM GLOBAL TECH OPERATIONS LLC	2	2016–2019
RHOADS FREDERICK W	2	2013
ALLIS CHALMERS	1	1980

Locations