The present invention relates to a root chipper , which re¬ moves root swellings from a log, of that kind which is set forth in the preamble of the following claim 1.

Saw logs having root swellings and a large root portion coni city must be trimmed before they are sawn into deals in fram saws, band saws or the like, or the capacity of the saws wil be reduced. Also, root portions may get stuck between the saw blades , which results in a shut down.

By laid out Swedish Patent Application 8203956-1, there is known a machine, which removes root swellings from a log. Th machine comprises a support device having support members, which retain the log in a fixed position, as well as carryin members able to lower the root portion of the log towards a rotating milling unit, while the log is rotated by means mounted in said support members, the result being that the root end assumes a cylindrical shape.

The German Offenlegungschrift 2 920 579 also relates to a root chipper, which comprises an annular rotor having a pair of milling tools, through which rotor a log having root swel lings is pushed in order to give the root end a cylindrical shape. Furthermore, the allowed Norwegian patent application no. 129 668 relates to a rotor having cutters mounted inter- nally.

The above-described well-known root chippers are rather comp licated , expensive, power-consuming, noisy as well as not v ry economical as to wood material. Hence, one object of the present invention is to suggest a simple, less expensive, less power-consuming and more silent root chipper. Another object of the invention is to suggest a root chipper, which does not throw chips around and yet allows the operator an ample visual survey of the machining process. A third object

of the invention is to suggest a root chipper, which removes the least amount possible of root swelling material to make the log acceptable as a sawing object.

These objects are attained in accordance with the present invention, namely by means of the characterizing features set forth in the characterizing clause of the following claim 1.

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A log is preferably fed into the root chipper according to the invention by lowering it laterally towards its support device using a crane.

Brief Description of the Drawings

A more detailed description of an exemplary embodiment of the present invention is set forth as follows, reference being made to the accompanying drawings: 0

Figure 1 is a perspective view of the root chipper of the present invention having some portions removed in order to elucidate its construction;

Figure 2 is a vertical longitudinal section along line A-A 5 in Figure 1;

Figure 3 is a vertical cross section along line B-B in

Figure 2.

Detailed Description of a Preferred Embodiment of the 0 Present Invention

The root chipper presented in the drawings is used to trim root portions from logs, the swellings of which must be re¬ moved before the logs are to be sawed. This root chipper 5 comprises a support device 1, which is mainly horizontally disposed, rests on legs la, has a rectangular shape and is made of U-shaped steel beams. Three V-shaped support members 2 for a root log 8 are fastened to the upper face of support

device 1 and are designed to let root log 8 rest in a de¬ finite position. One of support members 2 is provided with 8 rolls 3, which are driven by an electric motor 3a and are provided with sharp axially oriented surface elevations. When electric motor 3a rotates rolls 3, a root log placed on support members 2 starts rotating in its fixed position. Also, root portion 9 of the root log abuts a stop 4, which by means of legs 4a is fastened to the left end of support device 1 (Figure 2) .

10

Furthermore, support device 1 is provided with a frame 5, which is movably disposed in support device 1 in its plane. Two beams of the frame are movably disposed in the U-shaped portions of the beams of support device 1. Frame 5 can be 15 moved to and fro between two end positions, roughly between support 2, which is provided with rolls 3, and stop 4, by means of a hydraulic device 7 having a piston 7a fastened to frame 5.

20 Frame 5 is provided with a knife 6 at its left end. Knife 6 has a parallellepiped cross section and is elevated above frame 5 by means of legs 6a fastened to the frame and thus upper plane surface 6b of knife 6 is parallell with the ax¬ ial planes through root log 8 as well as support device 1

25 and frame 5 but is situated below root log 8, when it is adjacent support member 2, which is provided with rolls 3.

When the root chipper is used, knife• 6 initially is placed close to support member 2, provided with rolls 3, and a

30 root log 8,9 is lowered onto support members 2 by means of a crane (not shown) or the like, its root portion 9 abutting said stop 4. Electric motor 3a is started and drives rolls 3 in ordarto tarn a major root swelling portion of root por¬ tion 9 downwards and below plane 6 b of knife 6, which plane

35 is parallell 'to the axis of log 8. Piston 7 a of hydraulic device 7 pushes forwards frame 5 and knife 6, which is fas¬ tened to frame 5 by means of members 6 a, and against stop

4, and consequently knife 6 removes that root swelling por¬ tion, which is situated below plane 6b. Subsequently, frame 5 with knife 6 is retracted to support member 2 and rolls 3 and electric motor 3a causes root log 8 to rotate into a new angular position in order to make another major root swel- ling portion project downwards to a position below said plane 6b and subsequently, a new second cutting is performed. Two, three or four such cuttings ordinarily are sufficient to make the root log acceptably trimmed for the above-de¬ scribed sawing operations.. This means that relatively small amounts of root swelling portion material must be removed from root portion 8 of the log.

The present invention is of course not limited to the root chipper described and depicted in the drawings. Claim 1 sets forth the general area of protection for the invention.