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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 = '156') AND (category.subclass = '89.11') ORDER BY date ASC, patent, type

Total of 2 patents found where: Class is '156'; Subclass is '89.11';

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T / S Patent Date Description Patentee Category Assigned To
 1926
U 1,590,457 June 29, 1926 Method of Testing Insulators
Manufacturing method of cutting a plastic insulator body to inspect it internally then put the parts back together before drying and firing		 VAUPEL, Albert
 Manufacturing Westinghouse Electric & Mfg. Co.
 1941
U 2,261,583 November 4, 1941 Method of Making Hollow Forms
Method of casting hollow forms		 HEMPHILL, James R.
 Manufacturing The Colonial Insulator Co.

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