REGULATION OF STEAM.

103

resulted, at this date, in the universal application of the link-motion,with double eccentrics, as first practically introduced by the Stephen-sons.

However, there are a variety of link-motions; with some the linksare curved, while others have them quite straight. Referring tothose 'most in use, namely, ’those with the curved link, attentionmust be drawn to the various plans adopted for connecting theeccentric rods to the link. Some arrangements have lugs forged on

a,

' -4

Fig. 52.—Locomotive Link-motion.w, Weigh-shaft.

the link, within, and others without, the centre line of the link for con-necting the eccentric rods (Fig. 52); other arrangements have no lugswhatever, but merely a plain link, having the eccentric rods connectedto the ends, on the radius line of the link (Fig. 53), this plan neces-sitating the eccentrics to have a greater throw than in either of thetwo former arrangements. Some links are constructed of two sideplates, with distance pieces, the eccentric rods being placed betweenthem; while in other arrangements the link is a solid bar of iron,

Fig. 53.—Locomotive Link-motion.w, Weigh-shaft.

with the eccentric rods at the top qnd bottom on the centre line of arc,described by the link. Then, again, the mode of lifting and suspend-ing the link is by a lever and rod, the point of Suspension on thelink is on the arc described by the radius line, and placed half waybetween the centres of the pins for the eccentric rods; thus the linkand eccentric rods are raised or lowered simultaneously. With otherarrangements the link is not lifted, but merely oscillates to and fro