Though one may not think of gears as being versatile, gear couplings are extremely much considered to be a versatile coupling. A equipment coupling is usually a mechanical gadget designed to transmit torque between two shafts that aren’t collinear. The coupling typically consists of two versatile joints, one fixed to each shaft. These joints are often connected by a third shaft known as the spindle.
Each joint generally consists of a 1:1 equipment ratio internal/external gear set. The tooth flanks and external size of the exterior gear are crowned to allow for angular displacement between your two gears. Mechanically, the gears are equal to rotating splines with altered profiles. They are called gears because of the relatively huge size of one’s teeth. Gear couplings are generally limited by angular misalignments of 4 to 5°.
Equipment couplings ordinarily can be found in two variations, flanged sleeve and continuous sleeve. Flanged gear couplings consist of short sleeves surrounded by a perpendicular flange. One sleeve is usually placed on each shaft so the two flanges line up face to face. A number of screws or bolts in the flanges hold them together. Continuous sleeve gear couplings feature shaft ends 
coupled together and abutted against each other, which are then enveloped by a sleeve. Generally, these sleeves are constructed with metal, but they may also be manufactured from Nylon.
Single joint gear couplings are used to connect two nominally coaxial shafts. In this application these devices is called a gear-type flexible, or versatile coupling. The one joint allows for small misalignments such as installation errors and adjustments in shaft alignment because of operating conditions. These kinds of equipment couplings are usually limited to angular misalignments of 1/4 to 1/2°.