Here are some drawings of the mechanism I used to pop-up the corpse in the Kitchen Sink Coffin. It's a real simple mechanism and if done correctly, the tots cannot see any of the working mechanism. The pneumatic cylinder is housed in the bottom portion of the coffin under the lid that doesn't open. Most of the rest of the mechanism is under the corpse or can be hidden with flat black spray paint.
 

   

   

  Halloween Home last update 5/2004