(under the class definition) Apparatus having a vane or abutment which moves incident to the expansion and contraction of the expansion chamber, said vane or abutment having primary means and separate and distinct supplemental means to move the vane or abutment.
(1) Note. Neither centrifugal force nor the weight of a vane or abutment is considered to be either a primary or a supplementary moving means.
(2) Note. The supplementary moving means may concurrently with the primary moving means move the vane or abutment or it may move idly in its prescribed path of movement in lagging relationship with the primary moving means to move the vane or abutment only when the primary moving means fails.
