Rigid dump trucks vs. articulated dump trucks
All dump trucks are not created equal, but most can be divided into two groups: rigid dump trucks and articulated dump trucks. Rigid dump trucks are characterized by a rigid or fixed chassis on which both the cab and the dump body sit. Articulated dump trucks have an articulated chassis. The truck's cab (tractor) and the rear dump or tipping body (trailer) meet at an articulation point that sits directly behind the cab. Instead of the traditional rack-and-pinion steering used by rigid dump trucks, articulated dump trucks turn by pivoting at the articulation point, more commonly referred to as articulated steering.
Advantages of articulated dump trucks
With articulated steering, all-wheel drive and differential locks, today's articulated dump trucks offer many advantages over traditional rigid dump trucks.4 A tighter turning radius makes articulated dump trucks much more maneuverable than rigid dump trucks in confined mines and in cramped construction sites. Large tires, a wider frame and a lower centre of gravity make articulated dump trucks ideal for extreme off-road conditions, including inclines and soft, muddy, frozen or uneven ground. And, unlike the fixed chassis of its rigid counterpart, the articulating frame of an articulated dump truck is less likely to twist when negotiating uneven ground. Sized between 25-40 tons, articulated dump trucks are the best option for navigating soft ground when compared to heavier rigid dump trucks.
Articulated dump trucks are suited for a wide range of mining, quarry and construction projects, including underground mining and tunnel construction. Articulated dump truck operators at these projects can put in anywhere from 8-16 hour days. As a result of these long operating hours, articulated dump truck manufacturers have made rider comfort a primary concern. Most of today's articulated dump trucks come with heated seats, air conditioning systems, user friendly controls and, in the case of the newer Volvo articulated dump trucks, the industry's first actively controlled ride-suspension system to reduce in-cab vibrations.9
The first articulated dump truck: the DR631
The origin of the first rigid dump truck can be traced back to Saint John's, New Brunswick. In 1920, Canadian inventor Robert T. Mawhinney patented his dump box for a truck. A mast between the cab and the dump box was powered by a winch and cable system in order to raise and lower the dump box.1
By the 1950s, early articulated dump truck prototypes consisted of tractors with attached reinforced wagons.2 But it wasn't until the construction boom of the 1960s that articulated dump trucks became popular. It was during this time that Lihnell, a Swedish manufacturer of drive chassis for tractors, introduced the first series-manufactured articulated hauler, the DR631.
After introducing the DR631, nicknamed Gravel Charlie3, Lihnell signed a marketing agreement with Volvo in 1966 and merged with Volvo in 1974. Soon thereafter, Volvo emerged as an articulated dump truck market leader.4
Other articulated dump truck manufacturers
Not to be outdone by its Swedish neighbours, Norwegian manufacturer Moxy Industries introduced a 6x6 articulated dump truck (the Viking D15) in 1972. From 1986-2000 it continued to produce articulated dump trucks under the Komatsu brand. After 2000, Moxy changed ownership a few times until it was taken over by Doosan in 2008.5 Moxy is known for introducing design features that optimized driver visibility, such as sloping engine covers and wide windscreens.6
Latecomers Bell Equipment and Caterpillar entered the articulated dump truck market in the late 80s. Bell entered the market in 1985 after introducing its B25, a 25-ton articulated dump truck. The Bell B50D (pictured above) is known as one of the finest models in the 50-ton class (you can find Bell B50D specs on RitchieSpecs). Besides its B50D, Bell is known for its many innovations, including standard on board weighing, keyless ignition, HillAssist, skip tip prevention, auto park application (APA) and standard turbo spin protection.7
Caterpillar entered the market in 1986 after purchasing design rights from DJB Engineering based in Peterlee, England. Almost a decade earlier in 1974, DJB Engineering had introduced its D250, an articulated dump truck featuring a Caterpillar engine and drivetrain components.5 Making up for lost time, Caterpillar introduced its own innovative articulated dump truck design feature in 1996: the D400e, the first ejector truck.5 The D400e uses a blade to push material out from the back of the body, eliminating the need for the operator to reduce the truck's speed or to raise the body in order to release a load. Like other manufacturers today, Caterpillar also offers articulated dump trucks buyers the option of an exhaust heated body very helpful when trying to cleanly release material from the body in wet or cold environments.
If you are looking to buy an articulated dump truck, search our current inventory to search all articulated dump trucks for sale at upcoming Ritchie Bros. auctions.