I am curious about this product and wondering if this patent is still valid even though it is over a hundred years old.
In reference to the patent: US621888
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Both patents have expired. The US5653413 "Patent Expired Due to NonPayment of Maintenance Fees Under 37 CFR " as is indicated in public PAIR. The US621888 has expired a long time ago. Haven't found any specific indication of that but according to wiki the longest period for patent validity was 21 years and it's way beyond that now.