Raise the green beam to bring the dartboard to far position (position for throwing the darts).
Lower the green beam to bring the dartboard to near position for taking back the darts.
Red arrows represent forces applied to the beam.
The blue cart moves due to gravity.
According to the game rules the distance between the front of the dartboard and the toeline is rather short (7 feet 9.25 inches, around 2.4 m), so is this idea really necessary? However the mechanism may find applications in other fields.