US patent application 2203569, Laurens Hammond, "Musical Instrument", published 1940-06-04 , filed 1940-03-08 Figures 15, 16, 17 and 18 show the positions of the player's hands on the keyboards of the combina More
US patent application 2203569, Laurens Hammond, "Musical Instrument", published 1940-06-04 , filed 1940-03-08 Figure 6 is a fragmentary plan view of the keyboards of the instrument; Figure 7 is a fragmentary More