Abstract: A device for translating linear to rotary motion comprising a housing member, a rack member disposed in the housing member for longitudinal movement therein and having a starting position, a shaft in the housing having a pinion thereon engaged by the rack, the shaft being journalled in the housing and being disposed generally perpendicular to movement of the rack member, the shaft extends outwardly of the housing and has a rotative driving member thereon, the rack member has a longitudinal opening therein at one end thereof receiving the cylinder of gas cylinder-piston assembly, the piston of the gas cylinder piston assembly engages an end wall of the housing whereby upon movement of the rack member the gas in the cylinder is compressed and energy is stored therein, a slave cylinder in the housing member is adapted to receive fluid under pressure from an external source, a floating piston in the slave cylinder is arranged to act upon and linearly drive the rack and thereby rotate the pinion, the shaft and the