Though one may not think of gears to be flexible, gear couplings are very much regarded as a flexible coupling. A equipment coupling can be a mechanical device made 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 linked by a third shaft called the spindle.
Each joint generally includes a 1:1 equipment ratio internal/external gear set. The tooth flanks and outer diameter of the exterior gear are crowned to allow for angular displacement between the two gears. Mechanically, the gears are equal to rotating splines with modified profiles. They are called gears because of the relatively large size of one’s teeth. Gear couplings are usually limited by angular misalignments of 4 to 5°.
Gear couplings ordinarily can be found in two variations, flanged sleeve and continuous sleeve. Flanged gear couplings consist of short sleeves encircled by a perpendicular flange. One sleeve is positioned on each shaft so the two flanges fall into line face to encounter. A number of screws or bolts in the flanges keep them jointly. Continuous sleeve equipment couplings feature shaft ends coupled together and abutted against one another, which are then enveloped by a sleeve. Generally, these sleeves are made of metal, but they may also be made of Nylon.
Single joint equipment couplings are used to connect two nominally coaxial shafts. In this program the device is named a gear-type flexible, or flexible coupling. The one joint allows for minor misalignments such as installation errors and changes in shaft alignment due to operating conditions. These types of gear couplings are generally limited by angular misalignments of 1/4 to 1/2°.
Gear couplings are torsionally rigid and so 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 internal gear. It’s a general coupling for all sorts of applications and accommodates all feasible misalignments (angular, offset and combined) in addition to large axial moments. Devices, bearings, seals, and shafts are therefore not subjected to the additional forces, sometimes of significant magnitude, which arise from unavoidable misalignment usually associated with rigid shaft couplings.
A flexible/rigid coupling comprises one flexible geared fifty percent and one rigid half. It does not accommodate parallel displacement of shafts but does accommodate angular misalignment. This kind 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 at least one 1,5° static angular misalignment per gear mesh. However, reducing the operational misalignment will maximize the life span of the coupling as well as the life of other machinery components such as bearings etc.
SERIES H Features & Benefits
Higher Misalignment Capability
Sizes 1-7 compensate for up to ±1 1/2° static angular misalignment per gear mesh.
Minimizing operating misalignment will maximize the life span of the coupling. Refer to the Set up and Alignment Guidelines for alignment recommendations.
Larger Bore Capabilities allow the most economical size selection for shafts up to 10 5/8″.
Higher Torque Ratings due to bigger tooth pitch diameters than additional couplings.
Versatility in that Series H’s are interchangeable by fifty percent coupling with competitive coupling styles.
1 1/2° Curved-Face Teeth are a prime feature of the Series H coupling, sizes 1-7. The crowned hub teeth are a 20° full-depth involute tooth type with flank, tip, and root curvature. When
used in combination with the straight faced sleeve teeth, these 1 1/2° curved face hubs offer elevated shaft misalignment capability
CENTER FLANGE BOLTING
All couplings feature precision-drilled flange bolt holes, and tight tolerance Grade 5 flange bolts to assure a long-lasting flange to flange and fastener fit. Exposed bolt flanges are
regular. Shrouded 
bolt flanges can be supplied through size 5. Size #5 1/2 and larger couplings are only obtainable with uncovered bolt flanges.
LUBRICATION
Each sleeve flange comes with two pipe plugs 180° apart. This permits assembly of a complete flex coupling with four lube plugs positioned every 90°, facilitating lubrication. The lube seal is normally a Buna-N O-ring to greatly help retain grease and exclude contaminants. KHP or KSG coupling greases are recommended in order to obtain maximum operating life.
Ever-power COUPLING Features & Benefits
The Ever-power equipment coupling comes in two basic product lines:
Ever-powercoupling for medium to heavy-duty applications
Sizes 1 1/2 through 7 with integral end ring.
Sizes 8 through 30 with bolt-on end band.