Portfolio comparison
DUAL PARKING METER Co vs William F. Semple
Side-by-side portfolio analysis — patents indexed, year ranges, and activity timeline.
Top Patents1 enriched
US 2118318· 1938
How the First Coin-Operated Parking Meter Works
Activity by Decade
1930s1
Top Patents1 enriched
US 98304· 1869
William Semple's 1869 Patent for Improved Chewing Gum
Activity by Decade
1860s1
How to use
Bookmark a comparison URL to save it. Format: /compare/companies?a=[slug]&b=[slug]. Also see patent-level comparison.