Tru-Trac Rollers is a leader in providing solutions to problems experienced with tracking and aligning of conveyor belts. Since the invention of the Tru-Trac conveyor belt tracker by John Cumberlege in 1993, the company has developed a full range of trackers for tracking the return and load-carrying side, from slow belts all the way through to high-speed, high load belts.

With the current global trend of downscaling employees and yet trying to increase production there is a growing need for a maintenance-free, reliable Tracker that really works. Tru-Trac, as one of the few companies in the world which specializes only in conveyor belt tracking, has gained unique knowledge and expertise in this field.

One of the challenges in tracking conveyor belts is that each belt has its own characteristics, and therefore there is no one answer to track every type of conveyor belt. Yet, for the most part the industry is using conveyor tracking technology that is 25 - 50 years old. These self-aligning idlers do work in some applications but have their problems, such as damaging the edge of the belt, damaging the belt carcass, not working on wet applications and center pivot seizures.

Features of a good tracker

After identifying the need in the market for a better tracker, Tru-Trac initiated an international patent search, examined the problems with existing belt trainers and combining that with company experience, engineers set out to design a tracker. It was agreed that a good tracker system:

• must operate in both dry and wet conditions
• requires a minimum force to activate the tracking mechanism
• does not rely on the edge of the belt to activate the tracking mechanism
• is maintenance free
• has vibration free rolling action
• has minimum working parts
• is simple to install
• has good traction with belt
• is of durable design

Conveyor belt tracking equipment - Tru-Trac Flat Return tracking roller

As a result the Tru-Trac Flat-Return Tracker was designed, one of its achievements in that it has been judged a winner by the South African Bureau of Standards Design Awards for Engineering design. This invention has been patented in South Africa, U.S.A., Europe, U.K., Australia and corresponding patent applications are pending in a number of other countries.

Principles of Operation

The Tru-Trac employs a unique and highly effective tracking action, which is non-damaging to the belt and kicks-in immediately if the belt begins to track off-line. Because it does not rely on contact with the belt edge in order to guide the belt, belt edge damage, which occurs frequently with other tracking systems, is avoided. The Tru-Trac has special tapers (similar to a crown pulley) on opposite sides of the tracker which causes the drum of the Tru-Trac to pivot about an internal, vertical pivot axis. The internal central pivot is perpendicular to the belt and this results in the tracking action always being on the same horizontal plane as the belt. For this reason the Tru-Trac works equally well with uni-direction / shuttle conveyors.

As the belt starts to move off center it will contact the taper section of the roller on that side of the belt. The difference between the peripheral rotational speeds of the tapered portion of the drum and the centre causes the drum to pivot about its internal pivot. The extent to which the roller will pivot, will depend on the extent to which the belt has moved off its central position. Since the roller is no longer perpendicular to the direction of the belt travel, the skew roller immediately steers the belt back to its central position.

Once the Tru-Trac has steered the belt back to the center, the opposite side of the belt will contact the taper on the opposite side of the drum and this will cause the Tru-Trac to realign itself perpendicularly to the belt.

Since the surface of the belt remains in contact with the Tru-Trac over the entire width of the belt, the tracking action is far more effective and immediate than those types of trackers that pivot away from contact with the underside of the belt.

Features

The bearings are mounted in the bearing housings in both ends of the drum, to provide support for the roller drum over its full length. This ensures concentric vibration-free rotation. Each Tru-Trac uses a pair of 6017 2RS Bearings to facilitate the design (internal movement of the shaft within the inner sleave) and therefore are well within their rpm and load specifications. This allows conveyor belts with speeds exceeding 7 m/s to be tracked.

The center pivot is unique and simple, consisting of a stainless steel pin within a solid mild steel center shaft. This combination of the dis-similar materials overcomes any possibility of seizure. As an added precaution graphite anti-seize compound is added and the whole unit is seal welded for life.

The drum of the Tru-Trac is rubberised in Natural Rubber (or specific coatings as per clients' requirements) which ensures good contact and traction between the surface of the belt and roller. The bearing housing, front and back seal have been specifically developed for entire Tru-Trac product range, to ensure effective sealing in adverse conditions.

A special adjustable mounting bracket has been developed which can be easily adapted to most stringer configurations. This bracket enables the tension and, if necessary, the tracking angle to be adjusted easily.

Tru-Trac Trough Tracker

For the load-carrying side the Tru-Trac Trough tracking roller was developed. Due to the fact that the load carrying side is in a trough formation a different tracking configuration was needed. Applying Tru-Trac Flat Return principles of tracking in the horizontal plane, wing rollers were incorporated into the design to activate our standard central pivot system. Appreciating the potential damage caused by wing rolls intercepting the belt at 90°. The activating wing rolls are set to have a maximum effective contact between the belt edge and the wing roller of 25° -55° and are compatible with all troughed belts from 15° - 45°. These wing rolls are set to miss the edge of the existing troughed conveyor belt by between 5mm - 10mm on either side.

As the belt moves off-center the belt slides up the wing roll and thus causes the Tru-Trac to pivot on its internal pivot and steer the belt back to center with minimum force. The unique aspect of the Tru-Trac Trough tracker is that the center roll does all the steering and not the wing rolls, as this is where the most effective steering forces are exerted.

Tru-Trac Dual Return Tracker

For extremely wide or heavy belts the Tru-Trac Dual Return tracking roller was developed to accommodate the excessive forces encountered in these applications. An external central pivot mechanism was designed instead of using a single cumbersome large drum, enabling a concentric and balanced rotation to be achieved. This results in an extended bearing life. Two separate tapered rolls are mounted onto the pivot mechanism, which can be individually replaced as wear occurs. The operating principle is identical to the Tru-Trac Flat Return tracking roller, the advantage of the split configuration has resulted in a highly sensitive tracking action.

Success Stories

The Tru-Trac product range has been extensively tested and has proven itself successful throughout the South African mining and material handling industry. It has been selected by ESKOM the South African power generation company from all the trackers on the market for long term testing and is being used on their plants. Potgietersrus Platinum is currently using the Tru-Trac to eliminate their spillage problems and belt damage. At Richards Bay Coal Terminal the Tru-Trac Dual Return tracker is being used on their 1800mm - 2500mm steel cord conveyors running at 6.5m/s, to help reduce belt mis-alignment, which was their primary cause of downtime.

De Beers Finch Mine were using conventional tracking devices, which were rendered ineffective whenever it rained or the belts were washed down. The installation of the Tru-Trac Flat Return has eliminated belt stoppages. Our latest achievement has been at Rapid Loading Terminal where the Tru-Trac is being used to correct the drifting and misalignment on both the return and troughing side of a 3km overland curved conveyor.

" TRU TRAC makes belt misalignment a thing of the past! "