Each key of the keyboard is connected to a jack by means of a pivoted lever. When a key is pressed down, the jack is raised and its plectrum (or quill) plucks the string. As the key is released, the jack falls back down and the string is free to vibrate.
Each jack carries a square block of wood known as a tongue, with a quill glued near its distal end. The other end of the tongue sits in a hole in a wooden rail, which transmits its movement to the jack at its distal end. The quill plucks the string, and as the jack moves away, the quill passes through a hole in the jack rail, allowing it to swing to one side to avoid catching on the string