. Locomotive engineering : a practical journal of railway motive power and rolling stock . eccentrics aresupposed to be keyed on the axle, and ifthe cut and try method is followed it ne-cessitates the removal of the eccentricsfrom the keys in order to get them out ofthe axle and then the replacing of the ec-centrics and straps and the coupling ofblades to the links. Then follows the ex-asperating experience of the fellow in the of the axle outside of the travel line of theeccentric center. Diameter of axle being 8 inches, radiusequals 4 inches; throw of eccentric being5J4 inches, radius of ecc
. Locomotive engineering : a practical journal of railway motive power and rolling stock . eccentrics aresupposed to be keyed on the axle, and ifthe cut and try method is followed it ne-cessitates the removal of the eccentricsfrom the keys in order to get them out ofthe axle and then the replacing of the ec-centrics and straps and the coupling ofblades to the links. Then follows the ex-asperating experience of the fellow in the of the axle outside of the travel line of theeccentric center. Diameter of axle being 8 inches, radiusequals 4 inches; throw of eccentric being5J4 inches, radius of eccentric path equals2% inches. So the offset will be multiplied by the ratio of .A., or Si. Therefore we have Ja X H X §f = practically J| inch offset. For convenience the diameter of theaxle and the throw of the eccentric canbe used instead of their radii, which givesus the following simple formula: O = A L DU Tin which 0 = Amount of offset. A = Amount valve is to be moved. L = Length lower rocker arm. D = Diameter of the axle. l/= Length upper rocker arm. T = Throw of Locomotive Engineering Fig. 2 Fig. 1 CHANGING LEAD. pit endeavoring to move an eccentric athirty-second of an inch, and not have itdraw back in the old set screw who has been in such a non-get-at-able and trying place can appreciatethe following method of getting theamount of offset to be given the keys with-out the laborious way described and with-out the errors caused by lost motion. In Fig. 1 we have a diagram of a valve,rocker, strap and eccentric. Assumingthat the valves of this engine have ^-inchlap and it is desired to reduce it to 54-inch, it is necessary to reduce the linearadvance an amount corresponding to thereduction of lap, planed from steam edgeof the valves, or yi inch. The upper rockeris 12 inches long and the lower one IIinches long from center to center, throwof eccentric $%, inches, diameter of axle8 inches. Now if the valve is moved %of an inch the center of the
Size: 2387px × 1047px
Photo credit: © Reading Room 2020 / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, bookdecade1890, bookidlocomotiveen, bookyear1892
