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