Page:The Kinematics of Machinery.djvu/348

 326 KINEMATICS OF MACHINERY.

E. Skew double slider-crank chain

22. (Turning) skew double slider, or swinging skew cross- block. ..

23. (Turning) skew cross-block

24. Swinging skew double slider

F. Single crossed-slide chain (GP*

25. to 28. Four mechanisms.

G-. Double crossed-slide chain (CP+) 2.

29 & 30. Two mechanisms.

This recapitulation furnishes the best possible proof of the necessity of our previous kinematic analysis to acquaint ourselves even with chains apparently so simple as (C") and those derived from it. We also see how absolutely necessary it was to choose definite names for those of the mechanisms found by our analysis which occur most frequently. These names have been chosen with care and systematically, and they can be easily remembered, especially in connection with their foimulse. The removal of unessentials, which they greatly promote, is an enormous help to the recognition of the real kinematic nature of the construc- tively complex forms which occur in actual machinery. "We shall also see immediately that we have in no way exhausted the list of mechanisms which can be formed from the four cylinder-pairs, notwithstanding its necessary limitations ; indeed that we have yet to examine another great family of them, quite different from those we have been considering.