Pocketbook of Useful Formulæ and Memoranda
for Civil and Mechanical Engineers

497 OK ENGINEERING FOBMULÆ. Joy’s Valve Motion. The essential features of the motion are a vibrating link V to which motion is given by a point in the connecting rod; and a lever L, one end of which is moved by a point in V, and the other end is connected with the slide-valve, whilst its fulcrum is forced by a radius-rod to travel through a curved path. The reversing is effected by moving the end of the radius-rod from C to D so as to alter the curved path of the fulcrum to the dotted line A B. A movable slotted link may be substituted for the radius- rod. The dotted lines show another position of the motion. PEAUCELLIER PARALLEL MOTION. The distance apart of the fixed points A and B must always — the length of the spare link BD ; C is the point that moves in a straight line; DE = FC = DF = EC; AF = AE; HL - JK; KH = LJ; HA »HIL; JD = iJL; HC =iHK. peaucelliek’s. hart’s modification. has fewer links it has mote K Though Hart’s modification joints than Peaucellier’s. 2