IP Library › Granted Patent US 4,333,155
Granted Patent Utility
US 4,333,155 · App. 06/040,131

Calculator having a modular keyboard

Inventor: John N. Johnston
Patented Case View Patent ↗
Granted: Jun 1, 1982 Filed: May 18, 1979
Inventor
John N. Johnston
Assignee (at issue)
Litton Business Systems, Inc.

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Quick Facts
Patent No.
US 4,333,155
App. No.
06/040,131
Filed
1979-05-18
Granted
1982-06-01
Kind
A