534
�KINEMATICS OF MACHINERY.
�The pair C, G results from a further simplification of form in
the same class, and it again takes several definite but general forms.
We may use for the symbol of these pairs, as we have done for former ones, a single letter. This presents no difficulty, as the
��FIG. 365.
two elements always have the same name-symbol. We have only to provide means for distinguishing them from the lower pairs, (the name-symbol being sometimes the same), and this can easily be done by adding a comma to the name-symbol. We have therefore the class
H, H or (T,) the general pair of hyperboloids, and within this the following subdivisions :
K, K or (K,) the pair of non-circular cones, C, C or (&,) the pair of non-circular cylinders, as well as the three special cases of greatest simplicity :
H, H or (H,) the pair of hyperboloids of revolution, K, K or (K,) the pair of circular cones, C, (7 or ( (7,) the pair of circular cylinders.
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