Stiffen the rubber suit on the outside of the sheet metal protected trunk, by adding a number of circular rings around the arms and legs.
Joseph L. Boucher and Emery H. Brault and Romuald Filteau’s patent can be read here: Boucher Brault Filteau’s patent
https://patentimages.storage.googleapis.com/84/51/21/9071d51b71d7bd/US463477.pdf
Joseph L. Boucher and Emery H. Brault and Romuald Filteau took out a patent for an improved diving-dress in 1891. They do not seem to have hampered by any previous acquaintances with practical diving operations, for they calmly state;
“… With the ordinary diving suit the pressure of the water on the body and limbs increases in such ratio as the diver descends that it is not practical to work at a greater depth than about forty feet…”
After this, it is scarcely surprising to find that the invention itself is typical of the amateur dabbler. It consists of three pieces of armour, interlocking in the manner of a jig-saw puzzle, and covering the diver’s head and trunk. Over this an ordinary diving-dress is to be worn. As in the case of Don Quixote’s helmet, cardboard armour would look just as well and be equally useful.
R.H. Davis “Deep Diving and Submarine Operations” page 590
Therebreathersite was founded by Jan Willem Bech in 1999. After a diving career of many years, he decided to start technical diving in 1999. He immediately noticed that at that time there was almost no website that contained the history of closed breathing systems. The start for the website led to a huge collection that offered about 1,300 pages of information until 2019. In 2019, a fresh start was made with the website now freely available online for everyone. Therebreathersite is a source of information for divers, researchers, technicians and students. I hope you enjoy browsing the content!