But it was his younger brother George, a major at the time, who was credited with the name on the S&W. He improved the design by making the action opening/closing wear parts replaceable, and by doing so, received a royalty on each gun sold. His older brother at that time was in charge of army ordinance, so it's thought the army dropped the S&W contract they had for political reasons related to the royalties. Sadly, George also used one to take his own life.
The latch parts of all the Smith and Wesson Top Break revolvers could be replaced. That was not the reason Schofield was able to obtain a patent on his redesign of the latch.
Schofield liked the early 44 caliber Smith & Wesson American design, the first Top Break revolver S&W made, but he thought the latch could be improved. The barrel latch was mounted to the barrel extension. In order to open the gun for reloading it required two hands. The shooter would reach over the top of the gun with the left hand while holding onto the gun with the right hand and lift the latch. With the latch lifted, the barrel could then be rotated down for loading.
Schofield was a cavalry officer. His idea was to mount the latch on the frame, so that the thumb of the right hand could pull it back. Then a mounted trooper could brush the barrel across his leg to open the gun. It only took one hand. He had a working model made up, then applied for and recieved a patent for his latch design.
Schofield then approached Smith and Wesson with his idea and the Schofield model was born. Because he owned a patent on the latch design, S&W had to pay him a royalty for every revolver they made using this type of latch. But Daniel Wesson, always the crafty old New Englander, set his engineers to work to try and find a way around Schofield's patent. But he didn't have to bother. The Schofield was only manufactured for a short time, from 1875 until 1877. Only about 9,000 were manufactured. After that, S&W went back to their older design for all the latches for all the Top Break revolvers they made, right up until the early years of the 20th Century.
Here is a close up of the latch of the Schofield. It is mounted to the frame by the pin near its bottom. Pulling the latch back with the thumb freed the barrel to be rotated down.
Here is a view of the gun partially open to show the two parts of the latch. The part on the frame is the part that gets pulled back by the thumb, the part above is the mating part, screwed to the barrel extension. Notice the rear sight is incorporated into the latch, and there is a matching groove on the other part to provide a clear sight line to the front sight.
This is the latch on a New Model #3. This is similar to the latch on the American and Russian models. It is mounted to the barrel extension. The knurled part is what rotates up to free the latch. Notice there is a cutout on the hammer. This clears a ledge on the latch. Unless the hammer is pulled back slightly to the 'half cock' position, the latch cannot be opened.
Pulling the latch up clears the two lugs on the frame, allowing the barrel to be rotated down for loading. Smith and Wesson went on to use this basic latch design for all their Top Break revolvers, including the smaller pocket models. It is actually possible to open the latch by pushing up with the thumb of the hand holding the gun, but it is awkward and difficult. Two hands are required to open the gun easily.
It is often speculated that Schofield used one of his revolvers to take his own life, but there is no proof of that.