Must be Sears bought them from HD Smith?

AJUN 641 by Skip Albright, on Flickr

More likely Irwin, since Dunlap wasn't used until after H D Smith went out of business.
From Vintage Machinery- Dunlap-

QuoteA brand of Sears, Roebuck & Co., made by Atlas Press, Central Specialty (later King-Seeley), Double A Products, and others. The Dunlap brand was first used in 1941, replacing the earlier Companion brand. It was reportedly named after the head buyer in the hardware department of Sears Roebuck.

http://vintagemachinery.org/mfgindex/detail.aspx?id=269