CHAPTER XX.

LAYING OUT LINK-MOTION 257

Preliminary Explanations.--Definition of Terms used.-- Conditions.--Problems Involved in Laying Out Link-motion.--To find the Position of Crank when the Piston is at Full and Half Stroke.--To find the Center Line of Motion and the Amount of Offset in the Lower Rocker-arm.--To find the Relative Positions of Crank-pin and Eccentrics when the Piston is at Full and Half Stroke.--To determine the Correct Length of the Eccentric-rods.--To find the Position of the Center of Saddle-pin.--To Find the Position of the Center of Lifting-shaft and the Length of its Arms.--Dimensions of Locomotives.