DESCRIPTION OF MOTION.
In this form of valve-gear, eccentrics and their equivalents are entirely dispensed with. The motion for the valve is taken direct from the connecting rod; and by utilizing independently the backward and forward action of the rod, due to the reciprocation of the piston, and combining this with the vibrating action of the rod up and down, a movement results which is employed to actuate the valves of engines using any combination of lap and lead desired, and giving an almost mathematically correct cut-off for both sides of the piston for forward and backward motion, and for all points of expansion intermediately. The general outline of the motion can be understood by an examination of [Fig. 28], which gives three views of the gear. The sub-figures 1, 2, and 3 show the motion in elevation, plan, and transverse section respectively.
Fig. 28.