Page:The Kinematics of Machinery.djvu/421

 AXOIDS OF THE CONIC CRANK CHAIN.

From these centroids we can, without any great difficulty, obtain the axoids which we require. 51 These are shown in Fig. 277. The two axoids ABC and A t B O l are similar and equal ; in the position shown, however, homologous points in them are 90 apart. We do not, of course, propose that the figures thus found should be used as piston and chamber profiles in the disc-engine, they simply enable us to obtain a representation of the amount of sliding which takes place between 5 and d when formed in the

FIG. 270.

FIG. -277.

usual way. This" may be gathered from the figure when it is remembered that in the common disc-engine b is made a flat disc and rZa cone whose vertex angle is 90 a. The determination of the axoids for the links a and c forms a further interesting problem ; their profiles are analogous to the pair of Cardanic circles forming the centroids of the double-slider chain