Analysis of harvester’s operation time utilization – mathematical model. Economic effects of application of large-productivity machines is closely related to organization of the harvesting process. The time losses on additional, unconnected with production phases of that process are especially important. Under Polish conditions, such phase includes e.g. machine passages to a night parking place, as well as passages between particular tasks resulted from splitting of these tasks. The undertaken investigations aim at explaining of the effect of selected organization factors on operating productivity of multifunctional machines. The dependences that determine duration of particular phases have been formulated together with the balance indices of working shift time. The presented model enables to learn the working day structure and can be useful in the process of undertaking decisions to improve organization of large-productivity machines’ operation in Polish forests.
Achievement of beneficial economic results of timber harvesting with the use of harvesters is greatly determined by appropriate organization of their operation. It is important to find the solutions that could maximally reduce the share of working day phases that are unconnected with production. The carried out simulation calculations enabled to determine the working time structure under most favourable conditions, without preparation of bases and making passages to them and under conditions similar to the real ones. The experiments were executed for various number of tasks; therefore, the effect of passages between bases on working day structure was investigated also. The obtained results showed a very strong effect of mentioned factors working day utilization. In most favourable conditions and 100 tasks, about 50% of total time is taken by operating time that is directly devoted to execution of tasks, while in less favourable conditions and 600 tasks only 5% of time is spent on timber harvesting with the machine; the remaining part of time can be regarded as the lost time.