This invention relates to a device for extracting and/or disintegrating piece materials, the device comprisin a -base with two or three arms, one or two of which are movable, one movable arm cooperating with one fixed or one movable arm and at least one of the cooperating arms being arcuate with its concave portion facing the other coopera¬ ting arm- Such piece ^' materials which can be treated by means of the device of the invention include materials which can be recovered, such as big objects on refuse or scrap dumps, e.g. refrigerators and the like,, but specifically wood waste, and above all stumps. At stump extracting on a large scale for utilization of stump wood it is of a great im¬ portance that the stumps are _. disintegrated to minor parts in connection with their being pulled out of the ground. A better transport economy .is then obtained i-n continued handling and at the same time a considerable part of adherent material, such as stone, sand and earth, will be - freed and comes loose. A number of different methods and devices have been used and suggested for extracting and splitting stump-s. The only equipment used at present to a large extent in Sweden is the so-called "Pallari"-stump-harvester (Swedish patent 7201217-53- This known device consists substantially of a combined gripping and splitting means suspended in a conventional crane jib (boom) and provided with digging teeth, which makes it possible to use it also for breaking loose stumps from the ground. The gripping and splitting device consists of a hydrpulically operated, very thick and relatively blunt steel plate _. , which is pressed in between two counter supports to carry out splitting. The steel plate is very thick to resist the lateral breaking effects normally occuring when splitting stumps. • The most essential disadvantages if this known devic ³ is, - except that it is very heavy and works too slowly - that the splitting device requires very- great forces

when splitting stump wood and that the bluntness of the splitting device also causes considerable wood losses in the form of splintered and crushed wood which is lost in a following wood cleaning process. Now it has been found possible to reduce wood losses to a considerable extent and to reduce the force required for the splitting. This is achieved by the device of the invention which is characterized in that two cooperating arms are provided w ^τ ith fixed or replaceable knives cooper- ating with each other and fixed during the disintegration in a plane of motion in such a way that at least one of them is provided with a groove adapted to receive a por¬ tion of the other cooperating arm intended for this in order to guide the arms and the knives, respectively. relative to each other.

The device can be suspended on the front of a forest engine running on wheels nr bands or in a crane jib(b om) of such a wood engine. ϊ.Then carrying ^" ut splitting Cdisint.e- gration)it is of a great importance that the splitting means (knives) are as sharp as possible so that smooth section surfaces are obtained and wood losses are mini¬ mized in this way. When splitting stumps it is suitable to cam- out the cut through the central υortion nf the stump parallelly to the direction of the fibers; thanks to thi-^ essentially less force is required for cleaving (splitting) the stump wood.

The arms are usually hydraulically operated and one arm is preferably shaped as a hook with an extended and reinforced outer portion (lower portion) on the very hook to achieve a contact surface to the ground intended for use in stump extraction. The hook end can be shaped as a fork but is preferably made in the form of a tip which can be removed or replaced. It is suitable that either, or above all., both these tips are made in the fcrm of a wedge (axe) so that these tips can be used in cleaving (breaking) .

Thus, this device can comprise a base, on which a hydrauli- cally operated knife is movably attached, which knife works against another knife (counter knife) . The extension of the movable knife (knife nose) slides into a guide at the movement of the knife, the edge of the knife being retained after the knife nose has entered the guide, in a plane of motion common to the counter knife independently of the fact if the material to be split lies perpendicularly to the knives or not. For breaking (cleaving) stumps the knife nose is thus preferably formed like a wedge penetrating the stump before the knives are brought into engagement.

If a hook-shaped arm (the lower leg) is projected as a tip to facilitate penetration of the arm under a stump, this tip is also preferably formed like a wedge, both wed¬ ges penetrating into the stump from each their direction, which facilitates breaking (cleaving) of the stump.

It is suitable that both arms_ar.e movable, i.e. also the counter knife is movable. The knives (knife and counter knife) are preferably straight, their grinding (sharpening) being easier. In order to achieve a suitable cutting angle the knives can be. divided into .two or more straight lengths which form angles between themselves. They are preferably arranged so that the knife edges-form a concave line against the knife edges of a cooperating arm. In principle _. , there is ho ever nothing that prevents the knives from being curved, and also in this case ^' the curvature is arranged so that the indicated concavity is provided. In another aspect the invention provides for a device for extracting and disintegrating a piece material; particularly stumps, compri≤-i-ng a base with two cooperating pivotable arms, movable substantially in the same, common plane of motion, the end of each arm being provided with ah wedge-shaped tip adapted to cleave the stump.

The invention is described more in detail in the attached drawings, in which Fig. 1 is a view of an

embodiment of the device according to the invention as seen laterally. Fig. 2 shows the device according to Fig. 1 as seen from above. Figs. 3 and 4 are side views of _. another embodiment of the present device, the device ^' . being shown in different positions; in Fig. 3 immediately before starting extraction and splitting and in Fig. 4 in the final phase of extraction and splitting. Fig. 5 is . a view of the device according to Figs. 3 and 4 as seen from above. Figs 6 and 7 are views of another device according to the present invention illustrating arms projected to tips having wedge shape.

In Fig. 4 the present device shown comprising a base 1 , a hydraulically operated driving rod 2 and a movable arm 3. The arm 3 is also hydraulically operated at 4. The base 1 is here provided with a fixed hook-shaped arm 11 with a tip 10 and a breaker plate 8. The arm 3 is provided with a straight knife 9 and the arm 11 also is provided with a straight knife (counter-knife) 7.

The device shown in Fig. 1 is illustrated in'Fig. 2 ^' as seen from above. The arm is here arranged in the form of a fork and terminates in two points 10 arranged on two legs 14. Between the fork legs 14 of the arm 11 a guide 6 is formed into which the nose portion 5 of the arm 3 enters and is guided. When the counter knife 7 is fixed relative to the groove 6 and the arm 3 is guided in this groove 6 the knives 7 and 9 will work in the same plane of motion and a sharp splitting (cutting, shearing) process ^■ will take place. The broader breaker plate 8 which is in contact with the ground in extraction, is also apparent from Fig. 2. This breaker plate is designed so that it can be preferably adapted between two root branches in the very extraction process.

The device shown in Figs. 3 and 4 for extracting and/or disintegration especially stumps comprises a base 1 _j hydraulically operated (4., 12) arms 5, 11 ncvably attached to the base 1 , one arm 5 being somewhat curved and carrying knives 9 λvorking against counter knives 7

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arranged on the other arm 11, which is arcuate like a hook and has an extended and reinforced outer portion in the outer part of the very hook, which reinforced portion forms a breaker plate 8. Both arms are drawn out to replaceable, wedge-shaped tips 13 and 10, respectively. The knives 9 and 7 are also replaceably arranged and shown here as two straight knives on each arm perpendi¬ cularly to each other. From a functional point of view the knives can be arcuate which a equally good result but in view of maintenance (grinding) they are preferably straight. It is apparent from Fig. 5 how the arm nose 5 with the tip 13 passes into a guide 6 in the hook-shaped arm 11. The arms 3 and 11 are then guided so that the knives 9 and 7 a.nd the tips 13 and 10 cooperate in a way correct for cutting.

When used at extracting and/or splitting stumps the device can either be operated in a direction away from th<* supporting device (wood engine or the-like) against the stump or towards the supporting device and the stump. At extraction the tip 10 of the arm 11 is first pressed in under the stump, which can be facilitated by the pressure plate S being alternatively pressed against the ground so that a leverage is obtained. The introduction of the device under the stump is also facilitated hy the nose 5 of the am 3 being pressed against the stuπp by the hydraulic means 4.

After the arm 11 has been pressed sufficiently far under the stump the arm 3 is activated by the hydraulic means 4 _. , the nose portion 5 being introduced into the guide 6. The knives 9 are then fixed in their plane of motion and the splitting (cleaving) of the stump can be finished without the knives 9 being guided out of their plane of motion cue to the shape of the stump. The movement of the knives 9 is carried on until they overlap the counter knife 7.

At splitting and extracting big stumps it may be suitable and sometimes necessary to- split then into two

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or more parts before they are pulled out of the ground. The device can then be operated by the hydraulic means so that the tip 10 is entered almost horizontally to the stump from one of its sides, after w ^r hich the stump is split by means of the wedge of the nose tip 13 and the knives 9. Finally the stump parts are broken up from the ground in the manner described- After extracting the stump portions or the whole stump the extracted parts can be further split by the aid of the knives 9 and 7.

The essential parts of the device illustrated in Figs. 6 and 7 are the base 1 with the pivotically movable arms 5, 11 having wedge shaped tips 10, 13 which can be replaceable. The tips are provided with sharp edges to cleave the stumps. The tip are preferably made of steel. It is possible to dispense with the guiding groove 6 and the knives on the concave portion of the arms.

For the time being the device shown in Figs. 3 and 4 is considered the most suitable embodiment of the inven¬ tion.