Bellcrank
![Illustration from 1908 Chambers's Twentieth Century Dictionary. Bell-crank, n. a rectangular lever in the form of a crank, used for changing the direction of bell-wires.](/Images/godic/202412/23/Chambers_1908_Bell_Crank3517.png")
A bellcrank is a type of crank that changes motion through an angle. The angle can be any angle from 0 to 360 degrees, but 90 degrees and 180 degrees are most common. The name comes from its first use, changing the vertical pull on a rope to a horizontal pull on the striker of a bell, used for calling staff in large houses or commercial establishments.