452
KINEMATICS OF MACHINERY.
114 -
Friction- wheels ; Belt and Rope-gearing.
.Friction-wheels are kinematic elements in force-closed pairs. Two corresponding wheels, such as those of Fig. 313, arranged so as to work in gear with each other, form a higher pair of elements of the form JB+,.R+ or R+ t E~ .
FIG. 313.
FIG. 314.
A pulley which guides a cord or belt, or by its rotation sets such an organ into motion, forms with it the pair R + > T> as in Fig. 314. Two such pairs (which are, as we know, force-closed), when suitably united, give us the belt.- or rope-train (as the case may be) shown in
Fiu. 315.
Fig. 315, if the shafts of the pullies and the connecting frame be added (cf. 44). The single rope-wheel or belt-pulley or drum forms with its shaft a link of the chain represented in the figure, the " endless " tension organ being itself another link.
