RINGSPANN high speed, low speed backstops for conveyor applications

High speed backstop (L) and low speed backstop (R)

RINGSPANN Australia, part of the global RINGSPANN group and an Australian subsidiary of RINGSPANN GmbH of Germany, is a leader in the world of mechanical power transmission equipment.

Not only are we the leading choice for many of our major customers, we also deliver excellent product and technical support and unparalleled customer service to our region.

In this article, we showcase why RINGSPANN is such a powerhouse of information when it comes to application guidelines. Our USA-based colleagues from RINGSPANN Corporation have compiled a ready reckoner for commissioning and selection of backstops for customer applications.

Taking the focus to customers at the installation level means that at RINGSPANN, we value the importance of our customer interaction at every step of the product life-cycle.

This translates to best practices in product usage and thereby ensures that our products don’t suffer from premature failure or unplanned downtime.

In the end, our customer satisfaction results in repeat business and RINGSPANN’s credibility as a serious participant in the mechanical power transmission industry.

Please contact us for any technical assistance and requirements for our other products. We are also leading manufacturers of freewheels, brakes, shaft-hub-connections (i.e., locking assemblies, shrink discs, rigid shaft couplings, locking elements), overload clutches, couplings, precision clamping fixtures and remote control systems.

With has nine manufacturing facilities in Germany and other countries spread across the globe. RINGSPANN’s service portfolio ranges from consultation and design and development, right through to the production of ready-to-install components.

Best practices for commissioning of integrated and external backstops

CONVEYOR EQUIPMENT MANUFACTURERS ASSOCIATION

BULK SAFETY COMMITTEE

Written by Rich Collins, RINGSPANN Corporation vice president

The purpose of this document is to serve as a guideline of best practices as it pertains to commissioning of integrated and external backstops that are used in bulk or unit handling conveyor applications.

One should always refer to instructions from backstop manufacturer, but the following checklists may be used for general reference in situations of installation, general inspection, or troubleshooting of backstops.

Backstops, also referred to as holdbacks, are mechanical devices used to prevent reversal of a loaded conveyor under action of gravity when forward travel is interrupted.

Backstops may be integrated to the gearbox or mounted externally, they may be high-speed or low-speed and they may be of the positive-locking (ratchet/pawl) or friction (sprag/roller-ramp) variety.

Integrated backstops

Integrated backstops are commonly located on the high or intermediate speed shaft of the gearbox where the torque loads are less than the output torque of the drive. Integrated backstops are bolted directly to the gearbox housing, operate up to motor speed and typically feature a centrifugal lift-off mechanism to reduce wear and heat during normal running operation. Integrated backstops are lubricated by the oil within the gearbox and are generally considered to be maintenance-free (unless otherwise specified by the manufacturer). The following checklist may be referenced for the purposes listed above:

Prior to start-up:

  • Verify direction of rotation is correct
  • Verify run-out of backstop (TIR) is within manufacturer’s specified limits
  • Verify backstop inner ring is axially secured and keyed to shaft, with key fully engaged
  • Verify gasket material is used on both faces of backstop outer ring
  • Verify all backstop fasteners are tightened to specified limits
Figure 1: General arrangement of conveyor drive with high speed integrated backstop on an intermediate shaft.

 

During operation:

  • At initial start-up, monitor motor amperage and conveyor take-up movement for any overload that could cause excessive tension buildup in the system and backstop
  • Shortly after start-up, determine baseline operating temperature of backstop and monitor for anomalies
  • Look for any indication of oil leak around backstop
  • Listen for any unusual noise coming from backstop
  • Note any localised temperature rise in backstop

External backstops

External backstops for low-speed applications are commonly located on the on the head pulley shaft of the conveyor (opposite of the drive) or on a double extended output shaft of the gearbox. External backstops are self-contained, meaning that they have their own bearings, seals, lubrication and torque arm. External backstops are typically used for low-speed applications, but some may also be suitable for high-speed applications. The following checklist may be referenced for the purposes listed above:

Prior to start-up:

  • Verify direction of rotation is correct
  • Verify backstop inner ring is axially secured and keyed to shaft, with key fully engaged
  • Verify torque arm is properly fitted to support bracket with adequate clearance to prevent binding
  • Verify torque arm support bracket is sturdy enough to support the load specified by the backstop manufacturer
  • Verify breather and other lubrication piping is properly installed onto backstop
  • Verify proper lubrication type/ quantity is being used in compliance with manufacturer’s specifications
Figure 2: General arrangement of conveyor drive with low speed external backstop on the pulley shaft, opposite of the drive.

 

During operation:

  • At initial start-up, monitor motor amperage and conveyor take-up for any overload that could cause excessive tension buildup in the system and backstop
  • Shortly after start-up, determine baseline operating temperature of backstop and monitor for anomalies
  • Check oil level and look for any indication of oil leak around backstop
  • Make sure backstop inner ring remains axially secured to shaft
  • Make sure clearance between torque arm and support bracket remains free of debris
  • Verify regular lubrication maintenance and periodic oil sampling is being performed
  • Verify that possible movement of torque arm (due to shaft orbit) is not binding the torque arm
  • Listen for any unusual noise coming from backstop
  • Note any localised temperature rise in backstop
  • Verify that any wash-down operation of backstop will not compromise lubrication or seals

Other backstop configurations

There are many other backstop types and configurations for conveyor applications (especially multi-drive applications). Refer to conveyor original equipment manufacturer (OEM) or backstop manufacturer for specific information not shown in this document.

Troubleshooting

If backstop integrity ever comes into question, be sure to safely unload conveyor and contact conveyor OEM or backstop manufacturer for guidance.

For additional information on Backstops, CEMA’s 7th ed. Belt Conveyors for Bulk Materials has several chapters with information and CEMA’s Bulk Safety Committee is working on additional information.

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