The lengths of the links comply with the conditions: A͞B=D͞C and A͞D=B͞C. When cranks 2 and 2' turn about fixed axes D and A, link 3, carrying rotary knife 6 descends and enters a slot of carriage 9, thereby cutting off a cigarette from string a-a. Rotation is transmitted to knife 6 through bevel gears 4 and 5. Grindstone b is mounted on lever 8 which is connected by turning pair E to eccentric 7. Eccentric 7 is rigidly secured to crank 2'. In its upper position, rotating knife 6 contacts grindstone b and is sharpened.
$906$LW,FD$