INDICATOR 1W7551 - Caterpillar

Most torsional couplings use one or more torsional elements that are formed from rubber or from other polymers with similar physical characteristics. The torsional couplings are placed in series to achieve exact stiffness for reducing torsional vibration. The torsional couplings are also used for adding tolerance to parallel offset. These types of rubber couplings are used in generator sets.General Care
The following factors will accelerate deterioration of rubber:
Age
Heat
Ultraviolet light (UV light)
Petroleum products
Solvents
Anaerobic adhesives (thread lock compound)
OzoneAnaerobic adhesives can also deteriorate the bond between rubber elements and the steel flange or the hub.In an environment that is free of aggressive chemicals and free of light, the main cause of any acceleration of deterioration of the rubber is heat.There are five causes of heat buildup in rubber coupling elements:
High ambient temperature
Damping of torsional vibrations
Compensation for angular misalignment
Compensation for radial misalignment or for offset
Compensation for axial misalignment or for movementIn a controlled environment, the destructive conditions can be minimized. The rubber couplings can have a long useful life.
Illustration 1 g01322929
Flexible coupling
(1) Outer coupling
(2) Rubber element
(3) Hardness stampPreventive Maintenance Schedule
For torque specifications, refer to Specifications, RENR4952, "Flexible Coupling".Maintenance for the Rubber Flexible Coupling consists of four activities:
Keep the coupling free of excessive heat, UV light, petroleum products, solvents, anaerobic adhesives, and ozone.
Periodically inspect the rubber and the metal components for any imperfections, for stress, and for wear.
Check the torque for the fasteners periodically.
Check the alignment periodically.
Illustration 2 g01323258
(1) Rubber areas that are peeling away from the steel hub
(2) Wear at the loaded side of the teeth
Illustration 3 g01323319
Detail A
Cracks in the rubber
During visual inspection of the rubber element, note any rubber areas that are peeling away from the steel hub. 3 to 4 mm (0.118 to 0.157 inch) wear at the loaded side of the teeth is allowable. Refer to Illustration 2.During visual inspection of the rubber element, note any tears or cracks in the center of the rubber element. Refer to Illustration 3.