IP Library › Granted Patent US 4,240,522
Granted Patent Utility
US 4,240,522 · App. 05/968,210

Extension trestle ladder

Inventors: Kenneth J. Spear, Donald L. Shawkey
Patented Case View Patent ↗
Granted: Dec 23, 1980 Filed: Dec 11, 1978
Inventors
Kenneth J. Spear
Donald L. Shawkey
Assignee (at issue)
R. D. Werner Co., Inc.

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Quick Facts
Patent No.
US 4,240,522
App. No.
05/968,210
Filed
1978-12-11
Granted
1980-12-23
Kind
A