Helical Gear Speed Reducers
Provide high-efficiency speed right angle worm gearbox reduction through 1, 2, 3, or 4 sets of gears. Power is transmitted from a high-rate pinion to a slower-speed gear. Helical gears generally operate with their shafts parallel to each other. Both most common types will be the concentric (input and output shafts are in range) and parallel shaft (input and result shafts are offset). Single-stage helical gear reducers are usually used for equipment ratios up to about 8:1. Where reduced speeds and higher ratios are necessary, double, triple, and quadruple gear reduction stages can be used.
Worm Gear Speed Reducers
A single reduction acceleration reducer can achieve up to 100:1 reduction ratio in a little package. 
Known as right angle drives, these consist of a cylindrical worm with screw threads and a worm. With a single start worm, the worm equipment advances only 1 tooth for each 360-degree convert of the worm. So, whatever the worm’s size, the gear ratio is the ‘size of the worm gear to 1′. Higher decrease ratios could be created by using double and triple reduction ratios.
Basic Types of Gearboxes
The purpose of a gearbox is to improve or reduce speed. As a result, torque output would be the inverse of the function. If the enclosed drive can be a velocity reducer, the torque output increase; if the drive increases speed, the torque result will decrease. Gear drive selection elements include: shaft orientation, quickness ratio, design type, nature of load, gear ranking, environment, mounting position, operating temperature range, and lubrication.