Page:The Kinematics of Machinery.djvu/341

 CROSSED SLIDER-CRANK.

310

mechanisms crossed slider-cranks, and their uncontracted for- mula will be

C+...\\...CC-...\\...C-C+..._L...P+P-... + ...Cz (Fig. 250) or

C+...\\...C+C-...\\...C-C+... + ...P+P-......CE (Fig. 251) In place of one of the former symbols for normal we have here, either in the" link c or in d, the symbol for normally crossed, or crossed at right angles.

FIG. 249.

FIG. 250.

FIG. 251.

In its contracted shape the formula will run (C" 3 P+). The chain, like the more simple one (C^P- 1 ), gives us four mechanisms, corresponding to its four positions on d, b, a, and c. We may use for them the same names as before, prefixing the word crossed in each case. We have thus the crossed turning slider-crank, (C;P+) A the crossed swinging block (CP+) b, and so on. The motions occurring in these chains are more complex than in the