Though one might not think of gears to be flexible, gear couplings are very much regarded as a versatile coupling. A gear coupling is definitely a mechanical device made to transmit torque between two shafts that are not collinear. The coupling typically includes two versatile joints, one fixed to each shaft. These joints tend to be connected by a third shaft known as the spindle.
Each joint generally consists of a 1:1 equipment ratio internal/external equipment set. The tooth flanks and outer diameter of the exterior gear are crowned to permit for angular displacement between the two gears. Mechanically, the gears are equivalent to rotating splines with modified profiles. They are called gears due to the relatively large size of the teeth. Gear couplings are generally limited to angular misalignments of 4 to 5°.
Gear couplings ordinarily can be found in two variations, flanged sleeve and continuous sleeve. Flanged equipment couplings consist of short sleeves surrounded by a perpendicular flange. One sleeve is placed on each shaft so the two flanges line up face to encounter. A series of screws or bolts in the flanges hold them jointly. Continuous sleeve equipment couplings feature shaft ends coupled jointly and abutted against each other, which are after that enveloped by a sleeve. Generally, these sleeves are constructed with metal, but they can also be made of Nylon.
Single joint gear couplings are accustomed to connect two nominally coaxial shafts. In this program the device is called a gear-type versatile, or flexible coupling. The one joint allows for minor misalignments such as for example installation errors and changes in shaft alignment due to operating conditions. These types of gear couplings are usually limited to angular misalignments of 1/4 to 1/2°.

Gear couplings are torsionally rigid and are supplied to two styles – completely flexible and flexible/rigid. A completely flexible coupling comprises two hubs with an exterior gear and two external sleeves with an interior gear. It’s a common coupling for all sorts of applications and accommodates all possible misalignments (angular, offset and combined) and also large axial moments. Machines, bearings, seals, and shafts are therefore not put through the additional forces, sometimes of substantial magnitude, which arise from unavoidable misalignment usually connected with rigid shaft couplings.

A flexible/rigid coupling comprises one flexible geared half and one rigid half. It does not accommodate parallel displacement of shafts but does support angular misalignment. This type of couplings are primarily utilized for “floating shaft” applications.
Sizes 010 – 070 all have crowned teeth with a 20°pressure contact. This enables to accommodate up to 1 1,5° static angular misalignment per equipment mesh. However, minimizing the operational misalignment will maximize the life of the coupling and also the life of additional machinery components such as bearings etc.