Philip Adelbert Friedell.
United States Patent 1,730,270.
October 1, 1929.
Because this is a very old patent some technical terminology in the patent may be different from what is commonly used today. The gear arrangement of this invention can be practical only on high ratio so today it would be more appropriate to call this design a compound planetary rotary gear actuator.
We have rendered the ring gear 5 and the ring gear housing 12. As we can see, in 1929 the inventor has considered two different design concepts for mechanical rotary gear actuators: "said ring gear being integral with or fixed to said support or housing".
The inventor realized value of assembling the ring gear out of two different parts.
The inventor proposed a solution to fix the cylindrical ring gear inside the ring gear: "The planetary gears 3 mesh with the internal gear 5, which is pressed into the housing cover 12"