Hi Richie,
I've got a small brace with the same logo, in a similar position to yours, no other marking visible. But when I removed the head to repair a crack in the wood I found on the underside of the quill "D.R.G.M. AUROWA". Why anyone would put their branding out of sight like that is beyond me.
The DRGM is indicative of German registration used between 1891 and 1945. Google gives quite a few references to Aurowa braces and hand drills, but I've not found Aurowa and the logo together, which could mean that the quill on my brace has been replaced in an earlier life.
If you are contemplating removing the head to investigate, here's how I'd do it. It looks like there may be three screws holding the head to the quill on yours, remove the screws. Clamp the quill between two bits of wood in the jaws of the vise then grip the head in your hand and try to unscrew it. If it won't budge by hand it's probably time to give up. You want to continue, ok, wrap a leather belt around the head and grip it with a pipe wrench and gently try turning it. If it still won't budge then it's definitely time to throw in the towel.
Cheers,
Geoff.