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SELECT DISTINCT patent.*, YEAR(date) as year FROM patent LEFT JOIN category ON category.patent = patent.patent AND category.type = patent.type WHERE (category.class = '221') AND (category.subclass = '293') ORDER BY date ASC, patent, type

Total of 1 patents found where: Class is '221'; Subclass is '293';

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T / S Patent Date Description Patentee Category Assigned To
 1923
U 1,471,907 October 23, 1923 Machine for Heading Porcelain Tubes and the Like
Machine to make porcelain wall tubes		 MASON, Albert G.
BUCKLEY, Lorenzo C.
 Wall Tube The R. Thomas & Sons Co.

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