Sub miniature transformers

Patent:
US2949591
https://worldwide.espacenet.com/publicationDetails/originalDocument?CC=US&NR=2949591A&KC=A&FT=D&ND=3&date=19600816&DB=EPODOC&locale=en_EP


Used in UTC subminiature DO-T transformers:
http://www.steampoweredradio.com/pdf/utc%20transformers/utc%20transformer%20catalog%20circa%201970.pdf