How to extend Roberts' Law for eccentrically driven, inverted slider-cranks

The extension of Roberts' Law concerns inverted slider-cranks with an eccentricity and a general tracing-point attached to the moving plane of the slider. As both curve-cognates degenerate in this case, the infinite turning-joint has first been replaced by a finite far-away joint, but such that the coupler-plane also meets two accuracy-positions of the erstwhile slider. One of the curve-cognates may then be adapted or modified until up to six accuracy positions are met. They seem to be sufficient to attain an extraordinary good approximation of the entire branch of the original curve. Besides, even the transmission-angle attains a value about twice as large as the one obtained with the auxiliary four-bar representing the first approximation. Cases, where the inverted slider-crank turns into a crank-and-rocker, into a double crank or even into a stretchable four-bar, are shown. The latter corresponds with one of Grashofs border cases for the inverted slider-crank. Roberts' Law then ensures that each inverted slider-crank, having a fully revolving crank, possesses three four-bar branchcognates this way