Inline gearboxes have coaxial input and output shafts - the input shaft and output shaft share the same centreline or are offset on parallel centrelines in helical designs. This coaxial arrangement is mechanically the simplest gear drive configuration, minimising the number of gear stages needed for a given ratio and maximising power transmission efficiency. Single and multi-stage helical gear trains deliver ratios from 1.25:1 to approximately 100:1 in standard inline configurations. The shaft-aligned layout simplifies coupling to prime movers and driven machines - both shafts point in the same direction, enabling direct flexible coupling connection without angular misalignment concerns. Inline gearboxes are available with foot, flange, and torque arm mounting, and with hollow bore output shafts for direct shaft-mounted installation on driven equipment. For applications requiring a speed increaser (output faster than input), inline configurations are directly applicable by connecting the motor to the normally designated output shaft. This is relevant for testing applications, speed multiplier drives, and generator step-up requirements where the same gearbox model serves both reduction and increasing functions. Inline gearboxes are specified for pump and compressor direct coupling where coaxial shaft alignment simplifies installation, inline conveyor drives in packaging and food processing lines, fan and blower direct coupling in HVAC and industrial ventilation, and mixer direct drive systems. Their simplicity, efficiency, and coaxial shaft arrangement make them the lowest-cost, most maintainable choice whenever a right-angle drive change is not required.
