'Bumper' was the first machine to have bumpers on the playfield.
Patent No. 1,802,521 (GAME APPARATUS) was filed Aug 14, 1928 and issued April 28, 1931 to George H. Miner. Patent No. 2,109,678 (CONTACT SWITCH FOR BALL ROLLING GAMES) application was made on January 12, 1937 after the game was already in full production, and issued March 1, 1938 to Nils A. Nelson, a staff draftsman.
Bally's Bumper production began in 1936 and ran into 1937 with approximately 15,000 machines produced.