Stephen Stepanian -
Stephen Stepanian Stephen Stepanian (February 28, 1882 - October 1964) (Armenian: Ստեփան Ստեփանեան) was an Armenian American inventor and owner of numerous patents including the Elevator and Conveyor, Compound Tool, and the Wrench. He is also accredited as the inventor of a self-discharging motorized transit mixer that was the predecessor of the concrete mixer truck. [1][2][3