For many years standard sprag clutch backstops have been successfully used as safety devices to prevent inclined conveyor belts from running back when stopped in a loaded condition.

However, when conveyors stall because of an obstruction between the bottom belt and the return end drum extreme tension is caused in the top belt as standard sprag clutch holdbacks do not allow the slack bottom belt to ease through the drive.

The release of these obstructions has caused fatal accidents, when the uncontrolled release of tension in the top of the belt rapidly pulls the bottom of the belt around the end drum with a sudden surge of extreme force.

Renold have designed a range of Tension Release Backstops to deal with this potentially fatal force.

Fitting a Renold Tension Release Backstop to the gearbox drive shaft will ensure safe controlled release of the built up tension in the top belt.  This is achieved through controlled friction slippage of the sprag clutch element of the backstop.

The Renold Tension Release and Torque Limiting Backstops are a valuable additional safety device designed, not only to increase operational safety for your workforce, but also protects expensive plant against costly repairs and production downtime.

TYPICAL APPLICATIONS:

	Overland Conveying Renold Torque limiting backstops fitted to gearboxes on multi-drive overland conveyors to protect the gearbox and backstop clutch against overload and costly premature failure.  SH1051 Torque Limiting backstops fitted on to the gearbox output shafts of an overland conveyor handling iron ore protect the drives against damaging overload torques.  Instantaneous automatically controlled friction slippage of the sprag clutch element on the torque limiting backstops ensures total torque overload protection where it is most needed, on the gearbox output shaft of each drive.
	Mining Renold Tension Release backstops have been fitted to gearbox output shafts on conveyors in coal mines around the world.  A typical example of such conveyors is shown here employing Renold WA  or TRM backstop types fitted to the drive gearbox output shaft.  When the conveyor stalls or jams and the Renold SO or DM backstop sprag clutch element prevents any form of runback, which results in possible extreme and damaging tension in the conveyor belt, the tension release mechanism of the backstop is employed to ease out the tension in the belt.  This action safely protects both plant against damaging overloads, with resultant failure and downtime and the workforce against possible fatal accidents.
	Steel Mills Renold Tension Release backstops have been fitted to gearboxes on inclined material handling conveyors in steel mills around the world.  A typical example of such conveyors is shown here moving coking coal employing Renold WA or TRM backstop types fitted to the drive gearbox output shaft  with the torque arm fitted to gearbox housing.  When the conveyor stalls or jams and the SO backstop sprag clutch element prevents any form of runback. which results in possible extreme and damaging tension in the belt, the tension release mechanism of the backstop is employed to ease out the tension in the conveyor belt.  This action safely protects both plant against damaging overloads, with resultant failure and downtime and the workforce against possible fatal accidents.

Please click on the link below to view a short video showing how Tension Release Backstops can prevent fatal accidents when conveyor belt jams are removed.

 Tension Release Backstop Video

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