Forest tractor - LKT

This weekend my family met in the woods this machine. My four year old son very much wanted to buy this tractor (real tractor :-)). He talked about perhaps another three hours. So I created, at least in this simplified model this type of tractor. ¨
This is a "forest tractor LKT", which is still in production in the Slovak Republic ( http://www.lkttrstena.sk ). This particular piece can be produced in 1980 (but this is a guess). Central axis is really rotatable only in one direction (one axis