Houdini's Diving Suit patent was granted U.S. Patent Number 1,370,316 on March 1, 1921. The improved construction of the suit was a direct result of Houdini's interest in underwater escapes.
The patent reads: "The invention relates to deep sea diving suits or armors, and its object is to provide a new and improved diver's suit arranged to permit the diver, in case of danger for any cause whatever, to quickly divest himself of the suit while being submerged and to safely escape and reach the surface of the water. Another object is to enable the diver to put on or take off the suit without requiring assistance."
The trick to the suit was that it was constructed of two separate parts, with a latch for locking the two parts together in the middle. The diver simply had to reach this latch and the two pieces came apart. Obviously this type of suit would have been very useful to Houdini in performing one of his underwater escapes.
Houdini never used such a suit, though, in any public performance.