Complex sentence: Laurens Hammond graduated from Cornell University with a mechanical engineering degree in 1916, and by the start of the 1920s he had designed a spring-driven clock, which provided enough sales for him to start his own business, the Hammond Clock Company, in 1928.
Split into simpler sentences: Laurens Hammond graduated from Cornell University with a mechanical engineering degree in 1916. By the start of the 1920s he had designed a spring-driven clock, which provided enough sales for him to start his own business, the Hammond Clock Company, in 1928.