Design patent #D4,117June 7, 1870 by Joseph A. Ruff. Assigned to Metallic Compression Casting Co. assignor to Russell & Erwin.  Shown in the 1875 R&E catalog pg. 386, 2.5 inches $4.50 a pair, 2.25 inches $3.50 a pair. Click on each photo below to view additional images and information