In 1949 RCA Victor introduced the 45 rpm record. They did not invent the 45 adapter. major oversight. I've covered this previously in the broader context of vinyl. But the adapter has an interesting lineage that really allowed it to carry forward form novelty to standard. More here.
The Adapter didn't take long though. It's patent was filed September 1949; granted February 12th 1952. As you can see by the two above, they were in use long before the patent was granted. They were invented by Paul K. Bridenbaugh and Frank A Jansen for the Webster Chicago Corporation. I don't know another damn thing about them.
The design was simple, even elegant. It converted the 1.5" spindle hole to a 9/32nd spindle hole. It also added a small amount of weight, a tad more than 7 grams. This had the added benefit of increasing frictional contact between records in a stack. This allowed a stack of 45s so sit in an automatic record changer with the 9/32nd spindle. The patent refers to a few other patents, mostly phonograph related. But one single reference indicates a derivation. It's for a flexible bushing that is inserted into a worn spindle hole and bent outward to conform and adhere to the record allowing regular play. That is patent #1755743. Later revisions produced the more similar lightweight plastic adapters.