Definify.com
Webster 1913 Edition
Rock shaft
Rock′ shaftˊ
.[Cf.
Rock
, v. i.
] (Mach.)
A shaft that oscillates on its journals, instead of revolving, – usually carrying levers by means of which it receives and communicates reciprocating motion, as in the valve gear of some steam engines; – called also
rocker
, rocking shaft
, and way shaft
.