Step Chain Tensioner

Overview

The step chain tensioner, or tension carriage, keeps the step chain at the correct tension and absorbs chain elongation over the life of the escalator. It is a sliding assembly, so it has to move freely after years in a dusty, oily pit. One Elevator supplies complete tension carriages, slide blocks, springs and the adjustment hardware that keeps the chain running true.

Applications

Tensioners are replaced in metro stations, airports, shopping malls and industrial escalators on OTIS, KONE, Schindler, Mitsubishi, ThyssenKrupp and Hyundai equipment. A seized carriage is a frequent cause of step band sag, noise and chain derailment at the lower landing. Once the carriage reaches the end of its travel, the chain has to be shortened or replaced, so the remaining adjustment range is worth recording at every service. Pit access is usually the hardest part of the job, so we ship the carriage pre-assembled with the spring already compressed and pinned.

Types and Range

• Complete tension carriage assemblies with frame and shaft
• Slide blocks, guide shoes and wear strips
• Compression springs and spring packs
• Adjustment screws, locknuts and indicator plates
• Tension sprockets and bearings
• Grease nipples, seals and retaining hardware

Travel is measured and marked so the technician can see the remaining adjustment range.

Selection Guide

Choose by confirming three things: the frame mounting pattern, the sprocket and bore size, and the total adjustment travel. Inspect the slide faces at the same time — a carriage that cannot slide will not compensate for chain wear. Springs lose rate with age, so we recommend replacing them with the carriage rather than reusing the old set. All assemblies are checked for free movement, spring rate and weld quality before dispatch.

Ordering and Lead Time

Most sizes ship within 10-15 days. Send us a photo of your existing carriage with the mounting dimensions, and we will confirm compatibility and quote within one business day.

Frequently asked questions

How do I confirm the tensioner fits?

Send a photo of the existing carriage with the mounting dimensions and the spring rating. A seized carriage is what usually breaks the chain.

When should the tensioner be replaced?

When the carriage no longer slides freely, the springs have taken a set, or the chain cannot be brought to the correct tension.

Do you supply the springs separately?

Yes – springs, slide blocks and the complete carriage. If the frame is sound, the wear parts alone are usually the cheaper route.