1) The Foldable bed has a wide linkage which allows it to fold so that the bed can be folded into a sofa
2) The Bicycle has gears so that it can allow further distance travelled with less force.
3) The peg is a First class lever, which changes the direction of the load with less force required
When a foldable bed is pulled out, it does not pull out completely and requires effort to pull out completely. The additional part would be a tight spring, so that when the bed is unfolded, it will unfold completely and automatically