The present invention relates to a chipper machine, . particularly a mobile chipper machine for whole tree chipping, especially for chipping of first thinning stands, where it is desired to directly cut into chips one row of the regeneration stand.

Mobile chippers for whole tree chipping have been proposed already previously. To the extent these are designed as disc chippers they are too bulky, at least as far as the continent is concerned, where the spacings of the plants are normally very small. When these mobile chippers are instead designed as drum chippers the problem arises that such chippers often give a chip quality that ^' is only reluctantly accepted by particle board manufactur- ers and the like, to which should be added that the drum chippers normally demand considerably more energy per cubic meter of produced chips than what is the case with a disc chipper.

The present invention aims at providing a chipper machine which is less space demanding and has a low energy consumption, and which is easily adjustable in adaptation to the conditions in each particular case.

To the just mentioned end the chipper machine accord¬ ing to the invention has been designed so as is defined in principle in the characterizing clause of claim 1.

The invention will be disclosed in more details below with reference to the accompanying drawings.

Figure 1 is a side view of a chipper according to the invention, mounted on the front end of a tractor; Figure 2 is a side view of the chipper, shown in an enlarged scale.

In the drawings there is shown one embodiment of a mobile chipper, generally denoted 10, which is mounted on the front end of a tractor 11 which is coupled to a transport carriage with a storage hopper 12 to which the chips is fed through a channel 13. The chipper is design¬ ed for cutting up whole trees 14 into chips, with the trees normally being fed into the chipper with the root

end foremost and the top sliding along the ground as is shown in figure 1.

The chipper has a housing 15 wherein a rotary chipper disc 16 is journalled. The rotary shaft 17 of the chipper 5 disc 16 is journalled with a certain inclination to the horizontal plane, in the example shown with an angle of inclination of 40°, but this angle may vary, as will be disclosed in more details below. The chipper disc 16 is equipped with chipper knives 18 "of any commercially

10 normally available type and the disc is preferably with throughgoing openings for the chips, which is blown out through the channel 13. Adjacent the infeed opening of the chipper which is disposed on the "nearest" side of the rotary shaft 17 with the chipper disc 16 running clockwise

15 the chipper is provided with a counter knife 19 which has an angle of inclination of 10 to the horizontal in the illustrated position of the cutter to form an angle of inclination of 40 to the horizontal. At normally occur- ing lengths and bending down of the trees the inclination

20 of 10° of the counter knife 19 to the horizontal will correspond to the infeed direction of the trees.

It, should realized that the chipper knives 18 by the chipping will lift the trees into abutment with the counter knife 19. The enhance this lifting of the trees

25. and to simultaneously ensure a smooth feeding the lower¬ most portion 20 of the infeed chute is pivotally suspended and biased by a spring 21 to pivot upwardly, the bias force of the spring being such that "big trees are able to depress the lowermost portion of the infeed chute to the

30 bottom position.

The uppermost portion of the infeed chute is fully open to permit the trees to be easily placed into the infeed chute by means of a crane, not shown. When the trees are fed into chipper by means of the crane they are

35 placed against a stationary upper infeed roller 22 which guides the trees to the counter knife with a speed which is adapted to the desired chip length. The cutting angle and the mounting angles of the chipper knives are such that the chipper knives at the chipping pulls the trees

forwardly and lupwardly for which reason the feeding takes place very easily without need for any special feeding mechanism on the chipper or in connection therewith.

The chipper is designed for suspension from a three- point suspension by means of the struts 23, of which two are shown in figure 1. The correct angle of inclination for the infeeding (above supposed to be 10 ) may be adjusted by means of the struts 23 in such a manner that the stand in which the chipping is carried out will naturally be parallel to the counter knife 19 when the trees are placed in the infeed opening with the top ends sliding along the ground. The said angle is dependent on the.mounting height of the chipper above the ground level and the length as well as the diameter of the trees. In some case splints cannot be avoided at the chip¬ ping. As the splints normally stay on the front side of the chipper disc (the uppermost side as seen in figure 2) this side is not connected to the channel 13 for the outfeed of the chips but the splints pass a "throw in" plate 24 inside the chipper housing 15 where the infeed opening begins, so as to return the splints for chipping between the counterknife 19 and the chipper knives 18. As compared to previously known chippers the above described chipper has the following advantages: The infeed mechanism comprising the chipper disc 16 itself, the infeed roller 22 and the infeed chute 20 "holds" the trees and controls the movements thereof entirely up to the counter knife 19.

The chipper knives 18 tend to lift the wood from the lowermost portionf 20 of the infeed chute which means that the resistance to the feeding of the wood becomes very low. -

The chipper as a whole may be built very short which means that the center of gravity will be disposed very close to the supporting vehicle which is advantageous to the stability of the whole equipage at the same time as the operator gets a very good sight over the infeeding.

The chips is thrown out in the normally desired direction in a natural way, and furthermore along one side

of the equipage, for which reason e.g. a mounting of a crane on the tractor cabin does not mean an obstacle.

Due to the oblique position of the cutter disc 16 with the feed direction of the wood splints may be returned to the infeed chute at the counter knife 19 without risk for these splints to block the feeding mechanism or being thrown out therefrom.

A plurality of modifications and alterations as to details may be carried out within the scope of the invention.