Drawing of a bump gate, taken from US Patent <a rel="nofollow" class="external text" href="https://patents.google.com/patent/US2693653A/">US 2693653</a>, published Nov. 9, 1954.
A. Dean, jr.
<span><a rel="nofollow" class="external text" href="https://patents.google.com/patent/US2693653">U.S. Patent 2,693,653</a></span>