The online community of knife collectors, A Knife Family Forged in Steel
That is a PRESTO knife made by George Schrade company. It was awarded a patent Jan 30, 1940 if I am reading the tang stamp correctly. IIRC, the patent had something to do with the guards built into the bolster.
<edit> NOPE! it was for the locking mechanism. See the link below for the actual patent.
George Schrade was purchased by Boker in 1956, and closed in 1958 due to the anti-switchblade laws enacted that year in the U.S. So if you are looking for a manufacture date, it certainly lies between 1940-1958.