. The railroad and engineering journal . inks are suspended from a point halfwaybetween the points of coimection of the eccentric rods and fromi to J in. back of the center line of the slot in the link. A some-what better distribution can be secured by suspending them about Question 3S3. fV/mt is the effect upon the admission of in-creasing the thmu of the eccentrics with the same lap ? Answer. As already , the effect is to increase theperiod of admission, or, in other words, to cut off later in thestroke, and also to increase the width of the opening of thesteam-port or the distance
. The railroad and engineering journal . inks are suspended from a point halfwaybetween the points of coimection of the eccentric rods and fromi to J in. back of the center line of the slot in the link. A some-what better distribution can be secured by suspending them about Question 3S3. fV/mt is the effect upon the admission of in-creasing the thmu of the eccentrics with the same lap ? Answer. As already , the effect is to increase theperiod of admission, or, in other words, to cut off later in thestroke, and also to increase the width of the opening of thesteam-port or the distance which the valve throws over the has an important inHuence upon the admission, when thelink-motion is used. 3S4. IVhal is meant by the angular advance of theeccentrics ? Answer. It is the angle which a line, e f, fig. 245, drawnthrough the center/of the axle and the center^ of the eccentricmakes with a vertical line, a b, also drawn through the center ofthe axle when the crank is on one of the dead-points or f[J\ o\-^f-stb\\ Fig. 246. 3 in. above the center, but the suspending-links must then bemade so short that they are subjected to very great strains by themotion of the link, and this evil is usually considered muchgreater than the advantage which is gained thereby in the moreequal distribution. The point at which the upper end of thesuspension-link is hung also influences the relative amount ofadmission front and back. This point, of course, varies as theend of the lifting-arm is raised or lowered. The best positionfor the lifting-shaft and the length of its arm can be determined,perhaps, most satisfactorily by placing the link in full gear for-ward, then moving the point of suspension of the upper end ofthe link-hanger horizontally, so that the front and back admis-sion will be alike, and then marking this position. The sameprocess should then be repeated for half-gear and for the short-est point of cut-off. If the position of the lifting-s
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Keywords: ., bookcentury1800, bookdecade1880, bookidrailroadengi, bookyear1887
