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2020 / 2021 Edition

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Renold release conveyor safety video

Screen shot from Renold's safety video

New video demonstrates the dangers stalled inclined conveyors pose to employees and plant

A SHORT video produced by Renold Clutches & Couplings has been launched to demonstrate the dangers posed to employees and plant when an inclined conveyor stalls due to an obstruction between the bottom belt and return end roller. It also demonstrates how fitting a tension-release mechanism eliminates the danger and provides a solution that protects both employees and expensive plant.

For many years backstop sprag clutches have been fitted on inclined conveyors to stop them from running backwards, out of control, when stopped in a loaded condition. The same safety components are fitted to theme park rides to prevent cars from running downhill in the event of power loss.

The sprags in the backstop allow a shaft to rotate in one direction by slipping, but stand up and lock immediately if it tries to turn the other way.

With inclined conveyors carrying heavy loads, problems can arise if a blockage occurs between the lower belt and the return end shaft. The backstop sprag clutch will only allow the drive to turn in one direction, thereby tension builds in the upper belt as the slack in the lower belt cannot feed back through the drive.

Fatal accidents have occurred when this obstruction is removed, as the sudden release of tension in the top belt pulls the lower belt rapidly and with extreme force around the end drum. The massive, uncontrolled force it releases have, in the past, pulled workers removing blockages into conveyors and has caused the load on the top belt to explode in all directions.

A solution to this problem is to fit a Renold tension-release and torque-limiting backstop clutch to the gearbox. The range has been designed to allow the extreme tension in the upper belt to be safely released in a controlled way. This is achieved through the controlled friction slippage of the sprag clutch element of the backstop.

Renold’s safety tension-release and torque-limiting backstop clutch range not only protects employees from dangerous accidents, but also protects plant and equipment, and guards against costly downtime.

To view the video visit: (then scroll down for the video titled: Renold Tension Release Backstops).

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