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accelerating force angular velocity axis balance weight balancing masses balancing the reciprocating centrifugal couple centrifugal force connecting-rod corresponding couple polygon crank angles crank radius crank-pin crank-shaft cross-head curve cylinder centre lines cylinder engine direction distance drawing driving-wheel effect equal and opposite equation Equivalent mass expression feet fixed foot-lbs force acting force and couple force due force polygon frame given masses instantaneous value line of stroke magnitude main bearing main crank mass centre maximum value measured miles per hour motion pair parallel piston planes of revolution position poundals pounds problem radii rail-load ratio reciprocating masses reference plane represents respectively resultant revolutions per minute revolving masses right angles rotation Schedule secondary couple secondary forces shaft sheave shown in Fig sides simple harmonic motion speed tons trailing wheels triangle turning effort unbalanced couple unbalanced force valve-gear variables vector sum vertical vibration wheel zero
Page iii - Railways, and many cases of undue wear and tear and hot bearings in Mills and Factories undoubtedly arise from unbalanced machinery, though the actual vibration produced may not be great. In general, the running of an unbalanced engine or machine provokes its supports to elastic oscillations, and adds a grinding pressure on the bearings, and the obvious way to prevent these undesirable effects from happening is to remove the cause of them, that is to say, balance the moving parts from which the unbalanced...
Page 2 - Wvl 9 is the angular momentum relatively to the given point. Angular momenta are compounded and resolved like forces, each angular momentum being represented by a line whose length is proportional to the magnitude of the angular momentum, and whose direction is perpendicular to the plane of the motion of the body and of the fixed point, and such, that when the motion of the body is viewed from the extremity of the line, the radius vector of the body seems to have right-handed rotation. The direction...
Page 22 - DIGRESSION ON THE PROPERTIES OF COUPLES. 19. A Couple. — A couple is the name given to a pair of equal and opposite forces acting in parallel lines. The perpendicular distance between the lines of action of the forces is called the arm of the couple. In Fig. 20 the pair of equal and opposite forces F, acting in parallel lines a feet apart, form a couple whose arm is a feet long.
Page 177 - FIG. 126. scale of the drawing at the points where these parallels cut the line XR. The curve is properly calibrated by drawing horizontals through these points, repeating them and subdividing the intervals as much as may be required. The curve shows that the force at the top, dead centre, is about 51 tons, and on the bottom centre 31 tons, that when the crank is at right angles to the line of stroke it is 10 tons ; in fact, the disturbing force for this particular cylinder is known for any assigned...
Page 211 - K — the radius of gyration of the section about an axis perpendicular to the plane of bending — and inversely as the square of the length.
Page 213 - From the linearity of the equations it follows that the motion resulting from the simultaneous action of any number of forces is the simple sum of the motions due to the forces taken separately. Each force causes the vibration proper to itself, without regard to the presence or absence of any others. The peculiarities of a force are thus in a manner transmitted into the system.
Page 214 - For example, if the force be periodic in time r, so will be the resulting vibration. Each harmonic element of the force will call forth a corresponding harmonic vibration in the system. But since the retardation of phase e, and the ratio of amplitudes a : E, is not the same for the different components, the resulting vibration, though periodic in the same time, is different in character from the force. It may happen, for instance, that one of the components is isochronous, or nearly so, with the...