Unusual Pittsburg Hewlett Type Strain Disk

By Elton Gish; posted November 3, 2015

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In 1918, General Electric offered licenses to Locke and Ohio Brass for their Hewlett patents. Apparently they also offered them to Pittsburg H-V Insulator Co., too. This unusual 8-inch disk was intended to be a strain insulator. It was only offered in the Pittsburg Export Catalog No. 20 (circa 1920). It is characterized by the unusual design and a mold line around the center of the outside band. The Hewlett patents expired in 1931, which is about the time that type of suspension insulator fell out of favor because the issues that plagued cap and pin suspension disks were soon resolved.