The AGB barrel couplings for drums are used in the holsting gear of cranes to join the cable drum and the output shaft of the gearbox.
When the output shaft of the gearbox is rigidly fixed to the drum a statically indeterminate situation is produced, and it is difficult to obtain perfect alignment and levelling in assembly. Inexactitudes in the assembly, distortions in the structure, wear in the bearings, etc., all create additional forces which, jointly with the alternating bending forces, produce breakages due to fatigue and damage in the bearings and gear.
The AGB barrel couplings for drums are intented to avoid the presence of high bending moments and to compensate alignment defects. They are also intented to absorb axial displacement, an oscillanting bearing at the other end of the drum shaft being fitted for this purpose.
A barrel coupling consists of a sleeve and a hub fitted with semi-circular cogs, with a series of cylindrical hardened steel barrel sandwiched into the cog housings. The covers with their respective retainers, preventing dust from getting in and guaranteeing the continuity of the necessary lubrication. Spring rings guide barrels axially.
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