Construction The 300 SERIES BASIC UNIT comprises a backplate (9) to which is bolted the catcher assembly, consisting of load rings (1) and an index ring (2), each with a series of ramps. The auxiliary plate (6) encircles the index ring and is located in a recess in the wheel assembly (3, 4, 5) which in turn is attached to the rotating shaft. Indexing pins (7) are located between the index ring of the catcher and recesses on the inner diameter of the auxiliary plates. Load pins (8) are held between the angled slots in the auxiliary plate and teeth in the wheel rings.			Operation When the conveyor starts, the indexing pins and load pins ride up the ramps on the stationary catcher into the wheel recesses and to the top of the slots in the auxiliary plate. As speed increases they are held clear of the catcher jointly by centrifugal force and the auxiliary plate. When the drive shaft stops rotating the indexing pins locate on the ramps around the index ring of the catcher and hold the auxiliary plate stationary. Reverse movement of the rotating shaft, resulting from gravitational movement of the conveyor, drives the load pins down their angled slots to locate with the ramps on the load rings of the catcher assembly and the opposing ramps on the wheel. This creates a mechanical lock with the load pins carrying the reverse torque between these ramps, eliminating any frictional wedging action.
Where the Backstop is to be installed on the final output shaft, please consult Bibby Transmissions in order to ensure correct product selection. For other applications, please contact Bibby Transmissions for further discussion. Standard units have a safety factor of 2.0 included in the maximum torque settings.