Articles containing the keyword 'traktori'

The condition of forest road pavements was studied in spring, one week after maintenance and in autumn. The effect of vibrating blade was slightly better than that of pulled drag. Large loose stones couldn’t be pressed into pavement with either of the implements. The use of the vibrating blade was three times as expensive as the use of the pulled drag, however, the blade is suitable for other purposes as well.

The PDF includes an abstract in Finnish.

• Rummukainen, E-mail: ar@mm.unknown

The aim of this concise interview survey was to collect information about the servicing properties of forest tractors. Ten interviewees gave grades (in a scale from 4 to 10) concerning two servicing properties of various types of forest tractor. The rating covered the general safety during servicing (structural serviceability) and work postures during the work. Four types of forest tractor widely-used in Finland were chosen. The forwarders were of different size and structure.

According to the rating, the lightest forwarder was clearly superior to the other types. This machine was also the smallest in size and the most modern. Differences between the other three forwarders were not quite so clear. The variation between the machines as regards both so-called easy and troublesome tasks was considerable. Lubrication of the articulated shafts and supporting bearings was, however, very troublesome regardless the machine type. The heaviest tractor was considered the most difficult to service.

The PDF includes a summary in English.

• Rieppo, E-mail: kr@mm.unknown
• Väyrynen, E-mail: sv@mm.unknown

The mobility of logging tractors was tested in the winter 1969 on difficult snow conditions to gather information for planning of logging operations and for logging machinery design. The tractors tested were Clark Ranger 666, Timberjack C, Valmet Terra, Ford Brunett 5000, Fiskars 510, BM-Volvo SM 660, BM Volvo SM 661, Ford Country 6, MF-Robur I and BM-Boxer T-350.

According to the results, there is a preference of tracked vehicles in difficult snow conditions compared to wheeled tractors. Ford Country with long and bearing full-tracks proved to have the best mobility. On downhill grades it was found significant differences between three-quarter-track-tractors and skidders, although the performance on level ground and uphill grades was relatively similar. The tracked vehicles can easier move on the packed snow layer and reach a higher speed.

The driving speed does not increase significantly until the density of snow has entirely changed through getting wet. Wet top layer of snow affects positively on driving, because it increases packing of the snow. Increasing density of the snow improves especially the mobility of broad-tired wheeled tractors. To be able to predict the driving speed of a tractor in winter working conditions one must know the depth of the snow layer and the density of the snow and the grade of the slope. In addition, the passages on the same route and the packing of the snow must be regarded.

The PDF includes a summary in English.

• Silvennoinen, E-mail: us@mm.unknown
• Haarlaa, E-mail: rh@mm.unknown

Forest transport of timber in Finland has been arranged as horse haulage during winter time using horses vacant from farm work. Tractors have now begun to replace horses in agriculture, which will lead to shortage of horses for timber harvesting in future. The aim of this investigation was to find a method of mechanized forest transport suitable for Finnish conditions. The method should be provided by an agricultural wheel tractor that is shared with agriculture. It should also be applicable to timber transport of relatively small forest holdings.

A method for time studies of tractor driven timber harvesting was developed. The competitivity of tractor transport of timber against the traditional method was studied in four pulpwood harvesting sites. The results suggest that if the tractor forest transport method in question is to be applied in practice, conditions should first be chosen which favour it most. A tractor forest transport method evolved on the basis of experiments presupposes certain conditions to be successful. These include snow for the construction of the packed-snow driveway, frost to harden the driveway, the location of strip roads in relatively easy topography, and of the main haulage road that is gently sloping in the haulage-loaded direction. The optimal transport distance for this method are about 3-10 km.

The PDF includes a summary in English.

• Putkisto, E-mail: kp@mm.unknown