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Loaders
Published in John E. Schaufelberger, Giovanni C. Migliaccio, Construction Equipment Management, 2019
John E. Schaufelberger, Giovanni C. Migliaccio
A loader is a self-propelled machine with a bucket mounted on the front end. As with dozers, loaders are mounted either on tracks or on wheels. They are used to dig soil or other material, carry it, and dump it into trucks, stockpiles, or containers. A typical tracked loader is illustrated in Figure 8.1. Wheeled loaders may have either a straight frame or an articulated frame with a pivot point between the front and rear axle. Articulated loaders can turn in a shorter radius than straight-frame loaders of the same size. An articulated wheeled loader is illustrated in Figure 8.2. A straight-frame loader costs less to purchase and maintain per hour, but the productivity of an articulated loader is greater for truck-loading operations, because of its shorter turning radius. As with dozers, tracked loaders have better traction than do wheeled loaders, but they have slower travel speeds and generally require truck transportation to move them from one project site to another. Some manufacturers also offer rubber tracked loaders as illustrated in Figure 8.3.
Surface Coal Mining with Reclamation
Published in M. Sengupta, Environmental Impacts of Mining, 2018
After a sufficient length of pit has been opened, the haulback operation begins. In a full haulback situation, in which spoil cannot be placed downslope, a dozer works on the shot overburden, pushing it down to an end loader. Typical loader capacity is 12 cubic yards (9.17 m3). According to one engineer, with the exception of only the largest loader built, dozers must push to the loader because the loader does not have breakout force sufficient to excavate the sandstone overburden without the dozer assist. This is but one of the factors that makes haulback mining more costly than conventional contour mining.
Surface Coal Mining with Reclamation
Published in Mritunjoy Sengupta, Environmental Impacts of Mining, 2021
After a sufficient length of the pit has been opened, the haulback operation begins. In a full-haulback situation, in which spoil cannot be placed downslope, a dozer works on the shot overburden, pushing it down to an end loader. Typical loader capacity is 12 cubic yards (9.17 m3). According to one engineer, with the exception of only the largest loader built, dozers must push to the loader because the loader does not have breakout force sufficient to excavate the sandstone overburden without the dozer assist. This is but one of the factors that makes haulback mining more costly than conventional contour mining.
Harvesting forest biomass in the US southern Rocky Mountains: cost and production rates of five ground-based forest operations
Published in International Journal of Forest Engineering, 2019
Lucas Townsend, Elizabeth Dodson, Nathaniel Anderson, Graham Worley-Hood, John Goodburn
Loading was the least expensive function in operations when a loader was used. For knuckle-boom loaders the average observed loading cost was $3.62 per tonne. Operations ranged from 70% to 129% of this observed average cost per tonne (Table 13). Operation 3 which used a processor to load, cost 259% of the observed average cost per tonne for knuckle-boom loaders. Under modeled conditions, the average loading cost for knuckle-boom loaders was $3.68 per tonne. Operations ranged from 89% to 127% of the modeled average cost per tonne (Table 13). The processor loading on operation 3 maintained a high relative cost to knuckle-boom loaders, costing 198% of the average modeled cost per tonne.
Determining the environmental impact of material hauling with wheel loaders during earthmoving operations
Published in Journal of the Air & Waste Management Association, 2019
Hassanean S.H. Jassim, Weizhuo Lu, Thomas Olofsson
The first stage of the framework focused on data extraction and analysis. Data were gathered for the 29 Caterpillar wheel loader models listed in editions 42 and 44 of the Caterpillar performance handbook (Caterpillar [Cat.], 2012; Cat., 2014). A database was extracted from these handbooks containing the range of cycle times (i.e. the minimum and maximum cycle times, Ct, in minutes) for each wheel loader model together with each model’s bucket capacity (Bc) in m3, dump clearance at maximum raise (HI) in m, engine horsepower (Hp) in kW, hourly fuel consumption range (R) in L/h, and intervals of load factor relative to hourly fuel consumption (Hf), expressed as percentages for different earth types and work conditions. The wheel loaders’ cycle times for loading materials onto body haulers are specified in the performance handbooks for each model. In addition, haulage capacities (HC) in m3 were extracted for different wheel loader models to compute their loading times (Lt) in minutes, which were needed to develop simulation scenarios for earthmoving operations. The bucket payload (Bp, m3) is computed using data on the loose densities (Ld) in kg/m3 for each earth type or material loaded by the wheel loader, together with a fill factor (Bf, decimal) (see Eq. 1) and the wheel loader’s load factor (Lf, decimal) (see Eq. 2). Therefore, a load factor range was estimated for each material type considered in the study using a second degree exponential expression (see Eq. 2).
Dynamic simulation analysis on loader’s working device
Published in Australian Journal of Mechanical Engineering, 2018
Construction machinery plays an important role in the construction of modern buildings and undertakes the important task of providing various manufacturing equipment and production tools for economic construction. Loader is an important equipment in the field of construction machinery with the advantages of fast working speed, high efficiency, good mobility and light operation. There is a big gap between domestic loader technology development level and western developed countries, along with poor product R&D ability as well as difficultly adapting to the market demand. Thus, it is of great engineering application value to study the working device of loader by using modern design method. Since the early 1980s, a large number of experts and scholars at home and abroad have done a lot research work on loaders’ working devices by using modern advanced methods such as dynamic simulation analysis. In literature (Yang, Shen, and Li 2010; Yuan and Niu 2013), ZL50 and ZL80 wheel loaders are chosen as the research objects, and the virtual prototype models of the two types of loaders’ working devices are created in ADAMS. The kinematics analysis module in the software is used to study the working performance of the working device, including bucket translation, automatic flattening and so on. At the same time, the optimal design module in ADAMS is used. The performance of the above work is optimised reasonably and the result is satisfactory. In the literature (Zhang, Zhang, and Zang et al. 2010), by taking the working device of ZL50C wheel loader as the research object, the ADAMS software is selected as the research tool, and the simulation model of the working mechanism is established in the software. These working performance parameters are optimised and the overall performance of the optimised working device is greatly improved. In the literature (Bo, Zhu, and Ye 2014), the key technologies of modelling and simulation of rigid-flexible coupling system are studied, and the joint use of UG is put forward. ADAMS and ANSYS are the three softwares to establish the rigid-flexible coupling model of the mechanism, which enhances the interoperability when using the three softwares to optimise the design of the working device, accuracy and reliability. In this paper, the common domestic ZL50 wheel loader was taken as the research object.