Back in July of 2011, I did a post about a William Tell cast iron mechanical bank. At the time, all I could offer you were a picture and description. I've seen them in person at antique stores and shows, but because they seem to be worth a fair amount, I've never asked to see it work. There is currently another one for sale on eBay and this one comes with a video, which you see above.
The bank itself is an antique cast iron William Tell Mechanical Bank dating late 1800's. This model was patented in 1896 by Russell Frisbie and manufactured for 7 years by J&E Stevens Co.
From the eBay description:
To operate, the user cocks the launcher and places a coin in front of it. This "loading" of the mechanism also causes William Tell's head to lower into a position that makes it appear as if he is taking aim at the apple. Next, the boy’s right arm is pulled down bringing the apple to the top of his head. When ready to fire, the operator presses William Tell's right foot, the gun fires, and the coin shoots forward, knocking the apple from his son’s head as the boy simultaneously raises his right arm. The coin is deposited inside the castle tower, rings a bell, and William Tell's head falls backwards as if in relief.
Of the cast iron mechanical banks, this model is one of the most sought after variations. The original paint is in good shape, and this bank works great as you can see. Best of all, the seller warrants is not a reproduction because ownership can be traced back through her family. Beware of any "original" mechanical bank you find that seems like it is a deal too good to be true; I've spotted a lot of reproductions being presented as antiques. Here's a book about still and mechanical banks which features the William Tell bank on the cover.
I recommend the eBay listing itself. It is informative, contains 14 full of color photographs and is good reading. Here is where you can see the listing for this antique cast iron William Tell mechanical bank.