. The railroad and engineering journal . erealter^ Question 145. What effect does the angiilatity of the connect-ing-rod have on the cross-head and slides ? Ans-tver. When the crank is revolving in the direction repre-sented by the dart /in fig. 81, the connecting-rod is plainlysubjected to a compressive strain while the piston is movingbackward or toward the shaft, and during the first half of therevolution of the crank. The pressure on the cross-head andguides due to the angle of the rod is therefore upward. Whenthe piston is moving from the shaft, or making its forwardstroke, and the crank
. The railroad and engineering journal . erealter^ Question 145. What effect does the angiilatity of the connect-ing-rod have on the cross-head and slides ? Ans-tver. When the crank is revolving in the direction repre-sented by the dart /in fig. 81, the connecting-rod is plainlysubjected to a compressive strain while the piston is movingbackward or toward the shaft, and during the first half of therevolution of the crank. The pressure on the cross-head andguides due to the angle of the rod is therefore upward. Whenthe piston is moving from the shaft, or making its forwardstroke, and the crank is passing from , the connecting-rod is then in tension, and the pressure on the cross-head andguides is again upward. If, however, the crank should revolvein the opposite direction from that represented by the dart, thepressure on the cross-head and guides would be downward^that is, the direction of the pressure on the guides is reversedwhen the direction of the revolution of the crank is reversed,or when the engine runs tions of the center of the cross-head pin when the crank is at itsdead-points and when the piston is at the ends of its explained before, the cross-head and the piston are rigidlyconnected together, so that the motion of the one representsthat of the other. The movement of the center of the cross-head pin may therefore be regarded as the same as that of thepiston. If now. with a pair of dividers, we take a distanceequal to i I, or the length of the connecting-rod, and from 5 asa center a short arc, E, is described so as to intersect the center-line ABC. the point of intersection will represent the positionof the center of the cross-head pin when the crank is at 5, orwhen it has turned one-quarter of a whole revolution. If wesubdivide the distance i 9, which represents the stroke of thepiston, into two equal parts, i a and a g, then it will be foundthat the distance from i to E is somewhat more than i a, orthan half the stroke of the p
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Keywords: ., bookcentury1800, bookdecade1880, bookidrailroadengi, bookyear1887
