Hugh S. Knowles
Hugh S . Knowles ( September 23 , 1904 in Hynes Iowa – April 22 , 1988 ) was an American acoustical engineer , inventor , and manufacturer in the hearing aids field . 
<triplet> Hugh S. Knowles <subj> September 23, 1904 <obj> date of birth <subj> April 22, 1988 <obj> date of death