The present invention relates to a tree handling apparatus whose tree handling element is articulated relative to the body of said tree handling apparatus.

When handling a felled tree as a whole trunk it is pre¬ ferable that one end of the tree trunk be free to rest on the ground with the other end e.g. in the gap of a lopping machine. Thus, the entire weight of a tree trunk cannot stress the machine or apparatus handling it.

As the tree handling element, e.g. the lopping mechanism of a tree handling apparatus is pulling a tree trunk threthrough, the orientation of a trunk, particularly its angle of inclination relative to the ground, tends to fluctuate depending on ground irregularities, the branches and the remaining trunk length. Accordingly, it is preferable that the tree handling element of such apparatus be able to adapt itself to the changes of di¬ rection of a tree to be handled. This is to avoid the unnecessarily great loads on the body of a tree handling apparatus, caused by fully supporting a tree trunk. At the same time, the work result, i.e. the lopping, will be improved with the tree finding its way more accurat¬ ely through the lopping mechanism.

Free swaying of a tree trunk as it is being handled is in principle achieved in a quite simple manner e.g. by articulating the tree handling element of a tree handling apparatus relative to the body of such tree handling apparatus. On the other hand, however, the forces re¬ sulting from tree handling, e.g. from pulling the tree, bear upon this articulation or linkage, so it must be capable of withstanding considerable loading.

A solution of the invention is characterized in that the tree handling element is pivotably mounted in a manner that the fulcrum of said tree handling element is posit¬ ioned on a line of traction defined, by the tree lopping and pulling equipment.

According to one preferred embodiment of the invention, the linkage is provided by articulating the tree handl¬ ing element relative to the body of a tree handling apparatus by means of link rods in a manner that the interΞ'ecting line of the planes extending through the pivot axles of said link rods intersects a tree to be handled substantially at a line of traction defined by the tree lopping and pulling equipment.

In a solution of the invention, the linkage allows the tree handling element to find its way freely to the di¬ rection of a tree. Neither do the forces caused by tree handling result in substantially undesired wrenching between the tree handling element and the body of a tree handling apparatus, since the forces caused by the pull¬ ing of a tree divide into said link rods as tensile and compressive forces without the effect that feeding forces would tend to alter the orientation of said tree handling element.

In a solution according to another embodiment of the invention, the linkage is provided by articulating the tree handling element relative to the body of a tree handling apparatus by means of a circular arc shaped guideway, the centre of the radius of curvature of said guideway being positioned substantially on a line of traction defined by the equipment for lopping and pull¬ ing a tree to be handled.

The invention will now be described in detail with re-

ference made to the accompanying drawing, in which:

fig. 1 is a diagrammatic side view of the tree handling element of a tree handling apparatus, depicting the articulated mounting of the tree handling element relative to the body of a tree handling apparatus.

Fig. 2 illustrates the solution according to a second embodiment of the invention.

Referring to fig. 1 , the element generally designated by reference numeral 1 for handling a tree 12 comprises a lopping unit which is linked to the body 2 of a tree handling apparatus by means of a support arm 13. The body of a tree handling apparatus may be some working machine e.g. an agricultural tractor (not shown) .

The lopjjing unit 1 comprises a base designated by refer¬ ence numeral 16, to which are adjustably fastened lopping tools 14, surrounding a tree on either side thereof for effecting the lopping. The body 16 is also adjustably fitted with two drive gears 15 for squeezing a tree trunk therebetween and pulling it in axial direction, said lopping tools 14 cutting off the branches. A cut¬ off unit 21 finally chops the tree into logs of desired length.

The articulation of said element 1 for handling a tree 12 relative to said body 2 of a tree handling apparatus is effected by means of link rods 3, 4, the lopping unit being able to adapt itself to the* changes of direction of a tree being handled. Each link rod 3, 4 may comprise e.g. two parallel link rods fitted with common pivot axles or it may be a single wide link rod.

The positions and dimensioning of link rods 3, 4 are arranged in a manner that an intersecting' line 11 of planes 9, 10 extending- through pivot, axles 5, 7; 6, 8 intersects a handled tree 12 essentially: at ^' a line of traction defined, by the tree lopiing and pulling equipment 14, 15. Thus, a force, parallel to the tree and caused by the feed-in of a tree 12 by means of drive ^' gears 15, and the supporting forces transmitted by rods 3, 4, in the present case a compressive force in rod 3 and a tensile force in rod 4, intersect each other es¬ sentially at the same point 11 with the result that these forces do not tend to alter the direction of lopping unit 1.

In the embodiment of fig. 2, the same elements are given the same reference numerals as in fig. 1.

In the embodiment of fig. 2, the body 16 of a lopping unit 1 is fitted with a circular arc shaped guideway 17, the centre 19 of whose radius of curvature 18 lies es¬ sentially on a line of traction defined by the equipment 14, 15 for lopping and pulling a handled tree 12. Said guideway 17 is controlled by rollers 20 mounted on a support arm 13. Thus, the lopping unit 1 is able to find its way freely in the direction of a tree, nor do the forces caused by the pulling of a tree create sub¬ stantially undesired wresting between lopping unit 1 and body 2 of a tree handling apparatus.

Said circular arc shaped guideway 17 can of course be also fastened to support arm 13 and rollers 20 can be replaced e.g. by sliding surfaces. If absolutely necess¬ ary _/ such guideway 17 can also be provided by having perforated surfaces on either side of the mechanism at centre 19.

The invention has only been described above with refer¬ ence to two preferred embodiments thereof. However, this is by no means to limit the invention to just these two examples but a lot of modifications can be made with¬ in the scope of an inventive conception defined in the annexed claims. Hence, for example, a line of traction defined by lopping and pulling equipment varies with varying tree diameters, nor do minor deviations from the optimum intersection of axial planes or from the centre of the radius of curvature prevent utilization of the invention.