Hart-Parr Tractor Works, Oliver Chilled Plow works, Nichols &amp; Shepard (threshing machinery) and the American Seeding Company (Superior Grain Drills) were merged into the Oliver Farm Machinery Equipment Company in 1928 or 29 to form a company which would be a one stop source for farm equipment as Deere and McCormick-Deering (International Harvester Corp.) had become single source competition across the spectrum of having power, tillage, harvesting, and planting equipment at a single dealer serving the farmer. Your Cockshutt/Hart-Parr tractors would have been contracted by Cockshutt from Hart-Parr prior to the merger of the companies and have the company names.  After the merger they used OLIVER with Hart-Parr underneath until the mid 1930's as they blended the names which were known to gain cross acceptance of their products. In 1944 the Oliver Corporation was organized and most of the old names completely dropped.