The electric carving knife is a modern invention. In the home it is often seen as a `lazy luxury', although in a similar vain to the electric corkscrew it can be a great boon to those who suffer from such conditions as arthritis.
The electric knife operates by sliding two serrated blades past each other at high speed. These blades are so close together that they actually look and cut like a single blade.
To produce the oscillating cutting motion an electric motor in the handle rotates a rod worm gear. This in turn rotates a helical gear which has a blade attached to a pin on each side. Because the blades are attached 180 degrees out of phase (ie. if one blade is at the back position of the helical gear, the other is at the front), as the helical gear rotates it causes the blades to oscillate, as one moves out the other moves in and vice versa. This action takes place at very high speed, and because of the nature of the electric knife (ie. cutting meat), it is advisable to handle this kitchen appliance with extreme care!
