Modern instruments and methods of calculation : a handbook of the Napier Tercentenary Exhibition (1914)
Horsburg, E. M. (Ellice Martin), Napier Tercentenary Exhibition (1914 : Edinburgh, Scotalnd) · London : G. Bell · leaf 354
ate straight line. Watts Parallel Motion This simple four-bar mechanism, fig. 8, is the most important of thoseapproximate parallel motions which are formed by four turning pairs.It consists in its simplest form of two cranks, with the crank-pins joined by acoupler. In the mid-position, if the… … 326 SECTION I straight line is near the node of the closed path. See How to Draw a StraightLine, by Kempe. The importance of parallel motions in the early days of mechanicalengineering was due to the difficulty of cutting straight guides for the cross-head, valve spindle, and pump rods of the…
