Some issues of logging truck and pole semitrailer hitch strength

Nowadays logging trucks feature high operational parameters. Their carrier capacity and engine power increase while the specific ratio of truck weight decreases. This leads to constructional tensions growth. Logging trucks with pole semitrailers have been used in the Russian forest industry for more than 80 years. During this period the technology of timber harvesting and hauling has changed several times. At the same time, the pole semitrailer construction remained almost the same. As a rule, the carrier appears to be a jolt wagon equipped with a swiveling log bunk with winged poles. This article contains some results of our research of the pole semitrailers' tow bar strength which seems to be insufficient. We studied the tow bar load bearing capacity together with its basic technical parameters and its behavior in different unfavorable combinations of external loads.