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Before
self-propelled haulage vehicles, operators transported aggregates, ore, waste and fill by traditional means and repetitive standards. This format included loading the material into a box supported by a single axle drawn by a mule or horse and led by a driver using a short harness. Through repetition, the animals quite often learned to make the journey to and from the load and dump locations without a driver, however a driver needed to turn the cart around for dumping and positioning the cart for loading. Over the years, the internal combustion engine driving the rear axle replaced the horse and mule.


While the performance advantages of speed and payload have grown with the development of larger and larger engines, transmissions and tires, the basic design of the haulage vehicle remains the same. A loader puts material into a box largely supported by a single axle that is driven by a power plant and guided by a driver. The vehicle backs into its loading position, travels to the dump area where it turns around and dumps its load, then travels back to the loading area where it turns around and starts the next cycle.

The haulage cycle:

Today’s large haulage vehicles have grown into behemoths with payloads of hundreds of tons,driven by power plants of thousands of horsepower. But despite their huge size and capability, they still follow the path of the horse-drawn cart. Be it overburden and ore at a mine site,aggregate and fill for road building, or one of the many other applications of the large capacity haulage truck, the haulage cycle is the same. There is no escaping the fact that the truck must make two 180-degree turnarounds per cycle. In addition, today’s haul trucks must also reverse into position for dumping and depending on the loading procedure, must also stop and reverse into position for loading.

The patented vector-neutral truck eliminates the turnaround and back-up sections of the haulage cycle offering a performance advantage. The driver sits amidships (between the two axles) facing perpendicular to the line of travel.He drives by watching a multiple- screen display that is fed by multiple redundant cameras that produce a virtual view of the vehicle’s travel path. The truck drives directly to the load pick-up area without turning around. The payload is deposited into a dump bucket that is hinged on the main frame to discharge the load.The truck then drives toward the unloading site, again without turning around.Once at the site, the bucket unloads and the whole process is repeated. There is no differentiation in driver control and operation of the vehicle with respect to the direction of travel. It is insensitive to direction; hence its name, vector neutral. The major performance advantage of the vector-neutral truck is in the timesavings gained by not having to turn around and reverse with every haulage cycle. There are many more benefits flowing from the vector-neutral truck’s haul cycle in addition to the straight time and distance advantages. Fewer brake and steering applications mean reduced wear on the entire drive train, including less scrub and wear on tires. There’s less road maintenance because of the elimination of the turnaround area and it is simple to adapt remote and automated vehicle control. In addition, there is a reduced effect on the environment and the conservation of energy that results from travelling a shorter distance.

THE COMPARISON:

The two conventional trucks, a 60-ton capacity mechanical-drive Terex TR-60, and the multi hundred-ton capacity, electric-drive truck, the Liebherr T282, have the following common design. A power plant drives a rear axle with four tires either through a mechanical transmission or through electric wheel motors. The front axle, made up of two independently suspended tires and wheels largely supports the power plant. A driver sitting above the axle facing forward steers the truck. The payload is deposited into a dump box that is then hinged to discharge the load.

60-ton conventional carrier:

The TR-60 (Terex, 1998) has a 650 hp engine, located above the front axle, driving a single rear axle through a mechanical transmission. Four tires on the drive axle carry half of the vehicle weight when the vehicle is empty and two-thirds of the vehicle weight when it is fully loaded. The drive axle is connected to the main frame by a variable rate nitrogen/oil cylinder, with “A-frame” linkage and lateral stabilizer bar. The front axle is comprised of steerable Kingpin type suspensions, steerable rubber-tired wheels that combined carry half of the vehicle weight when the vehicle is empty and one-third the vehicle weight when the vehicle is fully loaded. Overall dimensions for the TR-60 are: 9.2 m long, 4.4 m wide, 4.4 m high, with a minimum outside turning radius of about 9.9 m. The driver sits above one of the front wheels facing forward. The payload is loaded into a dump bucket with a heaped capacity of 35 m3 that is hinged on the main frame.

400-ton conventional carrier:

The Liebherr T282 has a 2700 hp engine located over the front axle, driving a single rear axle through an electrical drive system. The rear drive axle is connected to the main frame with a three-bar linkage that is suspended on nitrogen/oil cylinders. Four tires on the drive axle carry slightly more than half the vehicle weight when the vehicle is empty and two-thirds of the vehicle weight when it is fully loaded. The front axle is comprised of two steerable, independently suspended Kingpin-type structures that combined carry just less than half the vehicle weight when the vehicle is empty and one-third of the vehicle weight when it is fully loaded. The Liebherr T282 dimensions are: 14.8 m long, 8.8 m wide, 7.5 m high, with an outside estimated turning radius of 16.2 m. The driver sits above one of the front wheels facing forward. The payload is loaded into a dump bucket with a heaped capacity of 183m3 that is hinged on the main frame.

Vector-Neutral Truck:

The vector-neutral truck has the same power plant as the conventional trucks. It is mounted amidships in the main frame, driving two axles through a mechanical transmission or electric wheel motors. Each of the two axles has four tires, which carry half the total vehicle weight, both when the truck is loaded and empty. The suspension members for the two axles are the same type of suspension components found on the rear suspension of the conventional truck, a three-bar linkage that is suspended on nitrogen/oil cylinders. These suspension members are fixed to a slew bearing that allows rotation of the axle and suspension about a vertical centerline. Rotating the axles equally and opposite to each other on the slew bearings steers the truck. The vector-neutral truck design has a horizontal pivot added to one of the two axles to accommodate roadway irregularities without transferring torsion loads into the main frame.

Today’s large haulage vehicles have grown into behemoths with payloads of hundreds of tons, driven by power plants with thousands of horsepower. But despite their huge size and capability, they still follow the path of the horse-drawn cart.

There is no new technology needed to build the vector neutral truck; the novelty and innovation are in the arrangement and combination of the components.

60-ton vector-neutral truck

A 650-hp engine drives through a mechanical transmission transfer case and drive shaft to two axles with four tires each. The fully enclosed operator’s compartment is located amidships, facing inward perpendicular to the line of travel. The 60-ton vector-neutral truck is 10.6 m long,5.2 m wide and 3.9 m high with an outside turning radius of 9.5 m.The dump box has a heaped capacity of 35 cubic metres and is hinged on the main frame.

400-ton vector-neutral truck

The vehicle has a 2700-hp power plant that drives through an electrical drive system to two axles with four tires each.The fully enclosed operator’s compartment is located amidships, facing inward perpendicular to the line of travel.The 400-ton vector-neutral truck is 19.9-m long, 9.1-m wide, and 7.5 m high, with an outside turning radius of 17 m.The dump box has a heaped capacity of 183 cubic meters and is hinged on the main frame. The calculated time required to stop the 400-ton or the 60-ton vector-neutral truck from a speed of 12.8 km/hr, and again from a speed of 8 km/hr results in a time of 0.13 min per haul cycle required to position for loading and dumping. The distance and estimated time required for a conventional truck to make two 180-degree turns, stop and reverse into position for loading or dumping is longer.One turn manoeuvre starts at 12.8 km/hr,the second manoeuvre starts at 8 km/hr.The time to complete these manoeuvres is 1.6 minutes per haul cycle for the 60-ton Terex, and 2.4 minutes per cycle for the 400-ton Liebherr. The biggest dimensional differences between vector-neutral and conventional trucks appear in overall length: 4.6 m for the 400-ton truck and 1.4 m for the 60-ton truck.This is caused by a slightly longer wheelbase on the vector-neutral trucks and a dump box that is longer than the conventional dump box.

The loading height of the 400-ton vector-neutral truck is one metre higher than the conventional truck,but the two trucks do have the same overall height. Loading heights on the 60-ton trucks differ by only 0.2 m. There is a slight difference in the turning radiuses, less than one metre for the 400-ton size, and 0.4 metres on the 60-ton version.Overall road width is the same for both the 400-ton vector-neutral and conventional trucks. The 60-ton vector-neutral truck is three-quarters of a metre wider than the conventional truck. There is also a difference in weight between the vector-neutral truck and the conventional truck due to the addition of two slew bearings to the major component list.This is partially offset by the deletion of the Kingpin and front suspensions, not needed on the vector-neutral truck. The vector-neutral truck’s,eight tires share the same payload and similar vehicle weight carried by only six tires on a conventional truck.This means either smaller tires or a larger payload when compared to the same sized conventional truck. From a physical standpoint,the vector-neutral truck is able to work alongside conventional trucks of the same capacity,with little or no changes to ancillary equipment or roadways. The vector-neutral truck uses the same major components (i.e. engines, transmissions, tires and wheels) as conventional equipment and thus would not require any special maintenance services. The comparison between the two different-sized conventional haulage trucks and their haulage cycles and the vectorneutral haulage trucks and their performances demonstrates the advantages of this new design.

Mike Parsons, C.E.T., is proprietor of Parsons Design.
Readers may contact him at 705-673-1232, e-mail: parsons@vianet.on.ca.
Web site: www.mikeparsons.ca.

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