bell crank 钟锤杠杆
钟形曲柄
直角杠杆
双臂曲柄
Bell crank \Bell" crank`\
A lever whose two arms form a right angle, or nearly a right
angle, having its fulcrum at the apex of the angle. It is
used in bell pulls and in changing the direction of bell
wires at angles of rooms, etc., and also in machinery.