. The Street railway journal . of shoesbut little worn with others on the same truck more nearlyworn out. To avoid this effect, all release springs are so at-tached as to act only at the tops of the live levers. All of these trucks can be provided with automatic turn-buckles, which will hold the shoes about 3-32 in. from thewheels till the shoes are worn out. This turnbuckle is soconstructed that when the brakes are applied, and also whenthey are released, it automatically lengthens itself, but it willnot change its length when the shoes are nearer than 3-32in. from the wheels. The distance at
. The Street railway journal . of shoesbut little worn with others on the same truck more nearlyworn out. To avoid this effect, all release springs are so at-tached as to act only at the tops of the live levers. All of these trucks can be provided with automatic turn-buckles, which will hold the shoes about 3-32 in. from thewheels till the shoes are worn out. This turnbuckle is soconstructed that when the brakes are applied, and also whenthey are released, it automatically lengthens itself, but it willnot change its length when the shoes are nearer than 3-32in. from the wheels. The distance at which the shoes are tobe carried from the wheels can be made more than 3-32 desired. The turnbuckle has a screw in a threaded screw pushes out a piston which carries one jaw whilethe pipe carries the other jaw. The screw is turned by thelongitudinal movement of the piston when the brake is appliedand released. Ratchet teeth, which are cut on the ends ofthe screw and piston and which fit into each other, do the. ELECTRIC MOTOR TRUCKS, TYPES O-50 AND C-60 action sufficiently for the journal box jaws to come in contactwith the pedestal part of the frame, so as to wear away thoseparts. It was found that the damping effect of an elliptic springhaving three or four leaves in contact gave the easiest ridingeffect, and when a larger number of leaves in contact witheach other was used the riding was not as good. For thisreason, when more than four leaves are required to carrythe load the springs are made with sets of three or fourleaves under the same bands, but independent of each other. By carrying the brakes on the equalizer bars the vibrationcaused by the brake application was eliminated from thetruck frame and the car body, and the shoes were always thesame height on the wheels, so that the brakes were as effi-cient with a full load as with no load. By locating the brake shoes at the M. C. B. standardheight, and by placing stiff compression coil springs on thebolts
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Keywords: ., bookcentury1800, bookdecade1880, booksubjectstreetr, bookyear1884
