Roll Knife / kitchen Knife

Many of accidents in kitchen are cutting skin by blade of un-organized knife. People are aware of danger of blade but these accidents are frequently happened.
This idea kitchen knife was inspired by danger of a knife's blade, Normally(Stocked), the blade is folded as roll, and un-folded when user try to use.
This idea is based on principle of shape-momory alloy. When user put a knife into cold water, blade of a knife is un-folded. To store knife, user can fold blade back by putting into hot water.
This process might be inconvenience , however this will prevent the future accidents by blade.