earthmoving dozer ripper arm frame cover - dozer maintenance

NEW PRODUCT: Dozer Ripper Frame Cover

March 15, 2023

National Plastics & Rubber are proud to launch our new Dozer Ripper Frame Cover

dozer ripper frame arm cover - lightweightOEMs, mine site maintenance crews, and workshop employees face the risky task of dozer maintenance on the daily. Safety managers are continuously seeking new ways to reduce hazards and the severity of the risks they present. Our new Ripper Frame Cover aims to create a safe work platform on the ripper arm.

Take the risk out of dozer maintenance with our load rated and lightweight Dozer Ripper Frame Cover. The ripper cover sits over the hole in the ripper frame and allows workers to perform all maintenance tasks without the hazard of falling through the hole.

Maintenance teams are currently using timber blocks and steel coverings to plug the hole. These “quick fixes” create additional risks for employees – they are heavy to manoeuvre, become a hazard for hand and finger injuries, as well as, crushing incidents.

earthmoving dozer ripper arm frame cover - dozer maintenanceAs a result, we developed a lightweight polyurethane Ripper Frame Cover designed to suit both Caterpillar (CAT) D10 and D11 dozers. Our cover allows you to perform all maintenance tasks without worrying about dodging the hole. Safely reach any overhead areas, hydraulics, and engine systems without risking a serious injury – crouch, lay, sit, or stand – it’s got you.

The cover features a number of benefits making it the superior choice for a safer workplace. Extra grip is provided with our patented high traction surface on the top of the cover. Independent and field tested, the cover is load rated up to 120kg – remaining stable with you and your tools on it.

Eliminating the risks associated with using steel coverings, our polyurethane cover is light enough (14kg) to be lifted overhead and slid into position by the maintenance crew before climbing on the ripper arm.

earthmoving dozer ripper arm cover



Lead the way for safety across your site – inquire today about our Dozer Ripper Frame Cover! Give us a call on 07 3279 3066 or email

PART NO: NPR08051-00

Lightweight wheel chocks for haul trucks & large vehicles

Chocks that stop!

February 17, 2023

National Plastics and Rubber wheel chocks have evolved to meet changing industry demands. An increase in regulation and mine site safety requirements drove the innovation of our range of lightweight wheel chocks. 15 years ago, NPR used to manufacture and supply a heavy range of chocks to national and international mining companies. Due to the desire for companies to embrace safety and an incident free culture – we replaced this range with polyurethane lightweight wheel chocks. Plastic and rubber wheel chocks do not present the same safety features as our innovatively designed wheel stoppers. The aim of our chocks is to directly address the health and safety risks associated with manual lifting on site.  Our entire range of wheel chock sizes from light vehicles (size 1.5) to even the heaviest of mining trucks (size 7) can be stopped with NPR’s Australian made wheel chocks.

Our chocks feature a unique design unlike any other chock on the market. All wheel chocks in our lightweight range, except size 4/3, incorporate the “toe” design. This design ensures the tire engages with the toe of the chock before it engages with the face of the chock; locking the chock and preventing it from slipping in extreme conditions. The success of this design is demonstrated by its adaption to our range of aviation wheel chocks – AerochockTM.


To compliment our wide range of wheel chock products, we have developed a size 4/3 wheel chock. This chock features the angled design of the size 3 on one side and size 4 on the other. We anticipated the different operational areas that chocks will be used across mine sites -from workshops to extreme remote locations. The 4/3 wheel chock was designed for service trucks to take with them when going out to service vehicle breakdowns. Instead of carrying multiple sized chocks, the mechanic will only need to take one chock with them. The chock may appear “double sided”, however you are only required to use one side or the other depending on vehicle and tire size. The chock covers all vehicles that wheel chock size 3 and 4 suit – this is the widest range of commonly used mine trucks.

How to use wheel chocks

All company and site specific safety requirements, policies, and procedures must be adhered to. Users are reminded to consider the number of variables that could affect a wheel chock’s performance.

Before using your heavy duty wheel chocks, it is important to check the chock for damage or missing components – like handles or cracks on the face of the chock. If you identify any kind of damage, discard the chock as it will be unsafe for use.

When chocking a vehicle on level ground, whether loaded or unloaded, we recommend using a minimum of two wheel chocks. Place one wheel chock in front, and one behind, of the front tire of the vehicle.

Where a vehicle is parked on a gradient, mine safety authorities have indicated that wheel stoppers are only required to be placed on the downhill side of the tire only. Chocks placed on the uphill side of a tire have no effect on securing, stabilising, or preventing unwanted movement of a large vehicle. If a haul truck is loaded on a gradient, four chocks placed on the downhill side, front and rear tires. When chocking an unloaded vehicle, we recommend using a minimum of two chocks depending on chock size. Place a chock on the downhill side of the left and right side tires on the downhill side of the vehicle.

Importantly, you must always ensure that the chock is fitted square in the centre of the tire.

Only remove a wheel chock it is safe to do so.

What is the workshop wheel chock?

We were recently approached by a large mining company to develop a purpose designed wheel chock product for the workshop environment. The features of our standard range of lightweight wheel chocks are reflective of the harsh conditions chocks face on site, including up to a 10% gradient. This conditions simply do not exist in a workshop environment, therefore altering the product requirements of a workshop chock. NPR’s workshop wheel chock features a unique design with wheels and handles to easily manoeuvre the chock around the workshop – reducing manual handling risks and eliminating the need to go under the footprint of the truck. Tilt the chock onto its back wheels to push chock to vehicle – when you get to the vehicle simply tip onto front wheel and use handles to help position chock square against the tire. Watch our instructional video.

Recognising its contribution to safety in the mining industry, the workshop wheel chock won both the Innovation Award and Peoples Choice Award at the QLD Mining Health & Safety Conference 2022.


Bearingless rollers

December 9, 2022

National Plastics & Rubber are the proud manufacturer of bearingless roller systems used across draglines, shovels and other mining equipment. Our innovative system was created in response to the numerous disadvantages presented by traditional roller systems.

Traditional roller systems consist of polyurethane bonded to a solid shaft that rotates on bearings. There are many disadvantages to this system:

  1. Wear out easily

The systems can wear out easily due to rope wear patterns, requiring consistent maintenance. As the polyurethane is bonded to the shaft along the whole length – and the rope generally wears on one section – the whole system needs to be restriped and lagging replaced, although wear has only occurred to one section.

  1. Cost of replacement

The cost of replacing a traditional roller system is unnecessary and unsafe. As the polyurethane is bonded to the shaft, when a segment needs replacing due to wear, the entire roller system must be removed and replaced. This is an expensive task requiring a crane or other lifting equipment to get the system out.

  1. Cost of having spares in stock

To keep machine downtime low, the system needs to be replaced almost immediately after it has been removed. That means numerous spare roller systems, in different sizes, need to be held in stock. There is also often a long turnaround time and lead time if you have stock and need to wait for a replacement roller system.

  1. Bearings can seize up

The bearings can seize up and the roller will then stop turning – causing the rope to wear through.

In response to these concerns, National Plastics & Rubber designed, tested and manufactured our now globally trusted bearingless roller systems. These systems pose many benefits to the mining community – improving safety, machine uptime and site productivity:

  1. Easy replacement

Our bearingless roller segments are manufactured from lightweight polyurethane and can be handled by hand (avg. 8kg) – eliminating the need for a crane or other lifting equipment. To replace a segment, undo the nut, the shaft spins out, and the segment can be changed.

  1. Standardisation

We encourage you to have the same segment across all areas of your machines. This will eliminate the need to store and stock multiple segment sizes and roller systems – a problem encountered when using traditional roller systems. Here, if you are using the same segment, no matter what length shaft or aperture you encounter, you only need to stock one segment – no need for different bearingless roller segments.

  1. Segment rotation

Bearingless roller systems provide you with the ability to rotate out segments that are experiencing wear. The worn segment can be rotated out and used as a spacer – and a new (unworn) segment can be shifted into the wear area. As a result, all of the material can be used, compared to a standard roller where if one section is worn out the whole roller system will need replacing.

  1. Bearing free

Of course one of the main benefits of our bearingless roller systems is that they are bearing free! Therefore eliminating the need for maintenance of the bearings as the segments simply rotate on the shaft. The bearingless roller system comes greased as well to ensure smooth rotation.

At National Plastics & Rubber we strive for continuous improvement, always seeking new innovation opportunities to meet customer inquiries and challenges. We possess state-of-the-art product design facilities to advance our current product range through customisation. Recently we designed a specific roller system to ensure continuous movement and free flowing spin of segment rollers.

National Plastics & Rubber looks forward to the opportunity to supply your site with bearingless roller systems. Give us a call on (07) 3279 3066 or email for more information or to arrange a shovel or dragline inspection Australia.

NEW PRODUCT: workshop chock

July 19, 2022

National Plastics & Rubber have expanded our trusted wheel chock range to include a NEW ergonomically designed workshop wheel chock. Complementing our range of quality tested mining products, this chock is purpose designed for the workshop environment.

What is the function of a wheel chock?

The function of a wheel chock is to prevent unwanted movement of vehicles by stopping wheels from being able to roll and move. Chocks can also be referred to as wheel stoppers, stop blocks, and tyre wedge.

For more information and to answer the question of “do wheel chocks actually work” – read our blog on NPR’s range wheel chocks and how they can benefit your family car or heavy duty mining truck fleet. Check out our range of light vehicle chocks and other vehicle, including 4WD wheel chocks.

At NPR we are also proud to offer a range of aviation wheel chocks. Our AerochockTM’s are lightweight aircraft wheel chocks suited for narrow and wide body aircrafts. View the range here.

INTRODUCING THE WORKSHOP WHEEL CHOCK – the easily-manoeuvrable, lightweight and durable solution

Designed in conjunction with Anglo Dawson, the workshop chock was created in response to an incident they experienced where a traditional wheel chock was installed incorrectly, driven over, and as a result became a projectile.

As these incidents were occurring in a workshop environment, we a designed a chock better suited to these conditions. Standard wheel chocks are made to secure a truck on a 10% gradient on the mine site, however these conditions are not present in a workshop. As such, the features present on our standard truck chocks could be removed from the workshop chock.

Featuring a handle and wheels, the workshop chock also eliminates numerous WHS risks – including back strain caused by repeat bending and chocking, as well as removing the need to go under the footprint of the truck.

As the workshop chock is not designed to suit extreme gradients, one size chock will suit all trucks – no need to purchase numerous sizes. One workshop chock will can be used all mining trucks, including CAT dump trucks, Komatsu miming trucks to even the biggest mining truck!

When should you chock the wheels?

NPR’s workshop wheel chock can be used in any workshop operations requiring the truck to be secured. During maintenance, for example, it is important to ensure large mining trucks do not have the ability to roll and move.

Do I need to chock both sides of the wheel?

Yes. Both sides of the tyre should be chocked with workshop wheel chocks. This will ensure the truck cannot roll either way.

Where should a wheel chock be placed?

Using the handles and wheels, manoeuvre the chock into position, this should be flush against the tyre with the handle against the sidewall. Watch our instructional video for more information.

National Plastics & Rubber’s workshop wheel chock for trucks is the ultimate wheel stopper for the workshop environment – preventing projectile chocks and ergonomically designed – a winner!

For more information or a quote get in contact with us – click here.

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