I'm not that old (but I may be a codger). That DP would have been sold in the mid-30's to maybe early 40's. Companion was the "economy" brand for Sears, with Craftsman being the "quality" brand. They were both essentially the same machine but one had less expensive components. Sears started replacing the Companion label with The Dunlap label around 1940, but there was some overlap as stock parts and inventory was used up.
The Companion name still pops up every now and then for short times every few years or so, I suspect it's only to keep the trademark active.
It's just a guess, but I'd bet that DP was made by Atlas.