In the 1940s and 1950s, Marx became the greatest toy manufacturer in the world, the most innovative and influential toy makers of the 20th century, but this is the first I've learned of the roller skates they patented

 

for the post about the toys: https://justacarguy.blogspot.com/2023/11/the-louis-marx-company-of-new-york-city.html 

https://patentroom.com/node/643