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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 = '142') AND (category.subclass = '20') ORDER BY date ASC, patent, type

Total of 3 patents found where: Class is '142'; Subclass is '20';

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T / S Patent Date Description Patentee Category Assigned To
 1883
U 278,619 May 29, 1883 Machine for Making Telegraph Insulator Pins
Machine to turn wooden insulator pins		 SMITH, John B.
 Pin Charles N. Freeman & David W. O'Neil
 1886
U 350,843 October 12, 1886 Machine for Manufacturing Insulator Pins for Telegraphic Purposes
Machine for turning wooden insulator pins		 ROGERS, Charles
 Pin  
 1887
U 360,215 March 29, 1887 Automatic Lathe
Insulator pin threading device		 FISHER, Frank E.
 Pin  

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