Safety coffins were a big thing in the 1800’s. The fear of premature burial was not entirely without merit. The wiki link mentions that during the cholera epidemic, they didn’t put a very fine point on the difference between “dead”, and “not dead, but we think you will be pretty soon.” Poe has entered the chat.
There was even a London Association for the Prevention of Premature Burial, who agitated for requiring a physician examination before someone was declared dead.
Lots of these contraptions were made, often with bell mechanisms and fresh air tubes for the prematurely interred.
The rise of cremation and embalming more or less ended the risk of premature burial.
According to the Internet, there is no record of anyone being saved by a safety coffin (false positives, on the other hand…)
False positives sound like an unpleasant process to discover. I wonder how many times those happened.
Edit. Also, though there are no recorded cases of a true positive, I wonder if there were false negatives, like someone really was alive, but nobody noticed the bell, or the mechanism failed in some way. Wikipedia does mention,