Milton Bradley, which was established in 1860, did not adopt a logo until 1941.
Milton Bradley's first version of their classic logo was adopted in 1943 and was used as their primary logo until 1963. It was still used in the "Key to Fun" logo until 1964. It could also be found on Operation money until 2008.
This variant appeared on some of MB's "Big Ben" puzzles from 1962 to 1963.
"Key to Fun" logo
The Key to Fun logo first appeared on the front of Milton Bradley games and puzzles circa 1950 and was used until 1986.
Action Man | Baby Alive | Blythe | Easy-Bake Oven | Furby | Glitter Force | Glitter Force Doki Doki | G.I. Joe | Jem | Kre-O | Littlest Pet Shop | Mr. Potato Head | My Little Pony | Nerf (Nerf Rebelle | Nerf Rival) | Play-Doh | Pound Puppies | Power Rangers | Tinkertoy | Tonka | Transformers | Weeble