Material management is critical to an efficient asphalt plant. Those who focus attention on the efficiency of their loader operations can achieve significant gains in productivity and profitability.
While manufacturers have done their share to boost efficiency with electronic controls, new hydraulic technologies and ergonomically designed cabs, decisions made at the jobsite will be the primary factor in how quickly and safely the work gets done. Properly preparing the site is an essential first step.
"Too often, operators don't take the time to prepare a place to load and unload, and then time is wasted dealing with uneven ground surface, resetting loads and poorly placed trucks," says Dan Snedecor, product manager for Volvo wheel loaders.
Provide room to maneuver
Snedecor says there should be sufficient space for trucks to enter and exit the site. In addition, the storage and loading/unloading areas should be carefully positioned to ensure the loaders have adequate space to move about efficiently.
"Operators shouldn't have to maneuver around several piles or bundles of material when moving between locations," adds Mike Keery, marketing representative for small wheel loaders at Caterpillar Inc.
The loading/unloading path should be designed so that trucks can back up to the pile at a 45-degree angle on the left side of the loader. This will minimize the distance between the pile and the truck, and will allow the truck's driver to maintain visual contact with both the loader and the loader operator.
"The loader operator should then position the machine in the dumping position and direct the truck to back under the bucket, parallel to the loader pins," says Keery. "This will create a pattern that minimizes loader movement and maximizes loading efficiency."
Once the path has been established, it should be "groomed" and maintained. Muddy or soft conditions can consume a lot of the machine's rim pull, slowing down production and increasing fuel consumption.
"Keep the work area clear of debris because rocks and ruts can affect the balance of the wheel loader, especially with the arms lifted," says David Wolf, marketing manager for Case CE loaders.
"While waiting for a truck, operators should use the loader to keep the working area clean," Keery says. "A smooth, firm working area can dramatically improve your loader's efficiency and reduce tire wear."
The right attachment
Matching equipment to jobsite requirements is also key to efficiency. While new bracket designs have made it much easier to change attachments, many operators still try to do everything with one tool.
And while most contractors are familiar with forks and buckets, many are not aware of the other tools they can use to improve efficiency. These include brooms, material-handling arms, grading buckets, barrel handlers and boom suspension systems that can reduce material spillage and increase travel speed.
Efficiency gains can also be realized with new loader designs and technologies. For example, load-sensing hydraulics give the operator complete hydraulic control at low engine speeds, eliminating the need to rev the engine to complete tasks in close quarters.
Hydrostatic transmissions also allow operators to precisely match engine speed to the work being done. One of Komatsu's new wheel loaders, for example, is equipped with a variable shift control switch that allows the operator to set a maximum speed of up to 8.1 mph.
On its larger wheel loaders, Liebherr Construction Equipment Co. has added two hydraulic motors, each with a separate clutch, to the transmission. "We use various combinations of these motors to achieve optimal operational and fuel efficiency," says George Seyrlehner, Liebherr's product manager for wheel loaders. "At least one motor is in operation when the machine is accelerated or braked, resulting in continuous power flow."
Hydraulically driven fans on loaders can lower fuel consumption and make more engine power available for primary functions. In addition, the fan flow can be reversed, which is useful for purging debris from the cooling system area.