Flexible couplings,

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With a medium speed system an number of engines and other devices are connected together. Flexible couplings are required to account for the slight misalignment which can exist. The claw type coupling as used with steam turbines allows for this misalignment and provides for a large area of contact which keeps he stress limited.

The diesel engine drive is pulsating and normal face to face contact cannot be allowed. Rubber blocks are therefore fitted between the claws. When the dive takes place the leading blocks are compressed allowing clearance at the trailing blocks which are hammered because of the pulsating drive. This results in wear. Blocks must there fore be pre compressed so that trailing blocks can expand and maintain normal contact with the drive.

Importance of precompression