January 2020

36 n GEARS AND GEARBOXES January 2020 www.drivesncontrols.com Speedy repair overcomes crushing failure at brickworks W hen a key gearbox failed on a crusher at one of the UK’s largest brick manufacturers, the company called in experts from Dana SAC to repair it and to get the machine up and running again as quickly as possible. “The equipment consisted of a conventional gearbox with a specialist crusher frame consisting of a pair of contra-rotating shafts clad with picks,”explains Dana’s aftermarket manager, Andrew Baggaley. “When functioning correctly, material is fed into the in-running gap, and is broken down into smaller pieces. The gearbox drives the lead shaft, and two spur gears synchronise the pair sharing the power.” When the gearbox was inspected, several major parts were found to have been destroyed. “The driven crusher shaft had lost the splined interface with its timing gear,” Baggaley reports. “The shaft itself is a large piece of steel with a lot of machined features – an expensive item to replace, and so we were keen to save what was an otherwise- serviceable part. The repairers opted for a keyed fit with three keys 120 degrees apart, and an interference fit. “The timing gears were worn, but we were able to take the secondary item and turn it to its better flank and re-use it,” Baggaley recalls. “The replacement for the scrapped item was made to suit the centre distance and modified to limit the backlash that would be caused by wearing it in with its mate. The whole interface between the output shaft and the crusher was badly worn, requiring re-boring and new oversize bearing cassettes to the driven end of the crusher frame.” The repair team wanted to minimise disruption to the brick-crushing process, so they re-used parts where this was possible, thus cutting costs and avoiding unnecessary delays to produce new parts. Similarly, where replacement parts were needed, bespoke parts were tooled and supplied quickly. “With this project, there were a range of issues with the original parts – due to wear and to age – and some of these were potentially very expensive for the customer,” Baggaley concludes. “The outcome we achieved – a mix of refurb and replacement – gave the customer the best possible solution with minimal disruption.” n After a gearbox failed on a crusher used by a UK brick manufacturer, the race was on to get it back into service as quickly as possible. An inspection of the failed crusher gearbox revealed that the splines to the driven crusher shaft had been destroyed The repair work included boring of the timing gear casing to realign the main bearing and cassette assemblies