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Excel Expertise: Increase Run Time with Overpitched Tumblers

Many operations have likely experienced misalignment and interference between the track shoe drive lugs and the drive tumbler contact faces on Hitachi® EX5500™ undercarriages. This type of misalignment can cause unnecessary wear on replacement drive tumblers and induce excess downtime for the operation. Excel design engineer, Aaron Henry and Senior Mining Product Engineer, Ryan Henry, have been working with a collection of operations around the world to create a custom innovation to fix the problem of misalignment between the track shoe drive lugs and the drive tumbler contact faces, thereby minimizing component wear and maximizing operation time.

We should first understand how and why misalignment happens and the resultant effect.  As an undercarriage continuously operates, all of the components begin to wear. As the track shoes wear, one critical area in particular involves wear in the pin bores. Wear in the pin bores will cause the track chain to elongate. Wear on other components such as the OD of the drive tumbler, idler and rollers, as well as wear on the track shoe roll path creates a situation in which the elongated track chain is mismatched compared to the reduced length about which the chain wraps. As a result, this will cause the track shoe drive lugs to become misaligned and interfere with the drive tumbler contact faces. This misaligned engagement results in greatly decreased component wear life.

Many times, shovel maintenance teams will only replace the drive tumblers when the wear on the drive tumbler contact faces becomes too great rather than replacing the dozens of expensive track shoes. This however, will only exacerbate the misalignment and interference problem as the track shoes are still elongated and will interfere with the new drive tumbler contact faces, rapidly wearing the new drive tumbler as soon as it is installed.

Excel’s solution to this problem is to replace the OEM drive tumbler with an Excel Overpitch Tumbler instead. When a drive tumbler with worn contact faces due to an elongated track chain is replaced with an overpitched tumbler, the resulting performance will simulate like-new pitch conditions because of the larger diameter of the tumbler. Essentially, with the Excel Overpitch Tumbler, track shoes can run effectively and safely for an extra 50% of their normal lifespan.


EX5500 Tumbler Wear Gif Excel Expertise: Increase Run Time with Overpitched Tumblers


For more information on how this solution can save your operation valuable time and resources, contact Aaron Henry (AaronH@ExcelFoundry.com) or Ryan Henry (RyanH@ExcelFoundry.com).


EFM Eblast Henry Brothers Web1 Excel Expertise: Increase Run Time with Overpitched Tumblers




Hitachi® is a mark of Hitachi Construction Machinery Co., Ltd. Excel Foundry & Machine is not an authorized repair facility of nor does it have an affiliation with Hitachi. These terms are used for identification purposes only and are not intended to indicate affiliation with or approval by Hitachi of Excel. All parts are manufactured by, for and warranted by Excel Foundry & Machine and are not manufactured by, purchased from or warranted by the original equipment manufacturer.

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