This would be a piggy bank that looks a lot like a small safe. Inside there would be a tray that the coins fall onto. It is held up by springs so that when enough
change is inserted, the tray will push down on the springs until it reaches a specified level which deactivates the locking mechanism and opens the box.
I think this would be exciting for kids because they wont know exactly when it will open, at some point they will just be putting some
coins in as usual, and suddenly it just pops open and the change spills out everywhere, almost like they won the jackpot or something.
I also imagine that the spring(s) could have some kind of tension adjustment which will allow some control over the amount of weight
that would be needed in order to disengage the lock
-----MORE TO COME-----