WO2006052182A1

WO2006052182A1 - A feed wheel

Info

Publication number: WO2006052182A1
Application number: PCT/SE2005/001597
Authority: WO
Inventors: Villgot Eriksson
Original assignee: Villgot Eriksson
Priority date: 2004-11-10
Filing date: 2005-10-25
Publication date: 2006-05-18
Also published as: SE0402761L; EP1809451A1; SE0402761D0; EP1809451A4; SE527833C2

Abstract

The invention relates to a feed wheel for longitudinal feeding of elongated objects, such as tree trunks, which feed wheel com- prises a hub (2), a shock-absorbing layer (3) of elastic material arranged around the hub, and a mantle (4) attached to the shock-absorbing layer. The mantle (4) is provided with gripping members (5) on the outside for gripping an object fed by means of the feed wheel. The mantle (4) is secured to the hub (2) by means of fastening members (6), each of which extending between the hub and the mantle through or at the side of the shock-absorbing layer (3). The respective fastening member (6) is bendable or compressible so as to allow the mantle (4) to be pressed down towards the hub (2).

Description

A feed wheel

FIELD OF THE INVENTION AND PRIOR ART

The present invention relates to a feed wheel for longitudinal feeding of elongated objects, such as tree trunks, which feed wheel comprises a hub, a shock-absorbing layer of elastic mate¬ rial arranged around the hub, and a mantle attached to the shock-absorbing layer, the mantle being provided with gripping members on the outside for gripping an object fed by means of the feed wheel.

The feed wheel according to the invention is mainly intended to be used in a harvesting arrangement, for instance in the form of a so-called grip harvester, in order to feed a fallen tree trunk through a branching device for branching of the tree trunk and up to a cutting device for cross-cutting of the tree trunk into indi¬ vidual logs.

The feeding of a tree trunk in a harvesting arrangement has to be carried out with a feed force that is sufficient in order to overcome the resistance from the branching device. A harvest¬ ing arrangement is usually provided with two rotationally driven feed wheels arranged to grip a tree trunk on opposite sides thereof. The rotational driving of the respective feed wheel is for instance effectuated by means of a hydraulic motor. The feed wheels are pivotable towards each other, for instance by being mounted on a respective swinging arm, so as to be pressable against the tree trunk with such a press force that sufficient frictional forces are exerted between the feed wheels and the tree trunk to make possible a feeding of the tree trunk with the required feed force.

A feed wheel provided with a shock-absorbing rubber layer be¬ tween an inner hub and an outer rigid metal mantle is previously known from the Swedish patent document SE 509 395 C2. The metal mantle is provided with gripping members on the outside in order to obtain a good contact with a fed tree trunk. The rub¬ ber layer is intended to damp for instance impacts and vibra¬ tions that the feed wheel is subjected to from a tree trunk which is being fed and processed, so as to thereby reduce the strain on the driving shaft of the feed wheel and the parts of the har¬ vesting arrangement connected thereto. The metal mantle is in¬ tended to protect the rubber layer against mechanical strain from fed tree trunks and is simultaneously intended to give the required grip with fed tree trunks via its gripping members.

OBJECT OF THE INVENTION

The object of the present invention is to achieve a further de¬ velopment of the above-mentioned feed wheel so as to provide a feed wheel with characteristics improved in at least some re¬ spect.

SUMMARY OF THE INVENTION

According to the invention, said object is achieved by means of a feed wheel having the features defined in claim 1.

According to the invention, the mantle is secured to the hub by means of fastening members, each of which extending between the hub and the mantle through or at the side of the shock-ab¬ sorbing layer, the respective fastening member being bendable or compressible so as to allow the mantle to be pressed down towards the hub.

In the feed wheel according to the above-mentioned SE 509 395 C2, the feed force is transferred from the hub of the feed wheel to a fed tree trunk via the shock-absorbing rubber layer and the outer mantle. The feed force is transferred from the hub to the rubber layer by friction between the hub and the rubber layer and further on from the rubber layer to the outer mantle via fric- tion between the rubber layer and the outer mantle. When oper¬ ating with a high feed force, there is a risk that the rubber layer will come loose from the hub, which will cause the rubber layer and the outer mantle to slip in relation to the hub and thereby make it impossible to transfer a required feed force to a tree trunk that is intended to be fed through the branching device of the harvesting arrangement. With a feed wheel according to the present invention, this problem can be avoided or at least essentially reduced, since the feed force in the inventive feed wheel is transferred from the hub to the outer mantle partly via the shock-absorbing layer and partly via the fastening members extending between the hub and the mantle. Said fastening members relieve the pressure on the shock-absorbing layer with respect to torsional forces, thereby reducing the risk that this layer will come loose from the hub.

According to a preferred embodiment of the invention, the mantle is flexible. Owing to the fact that the mantle is flexible, a more effective contact with the fed object is obtained as com¬ pared with the case when the feed wheel is provided with a rigid mantle. Hereby, the clamping force that has to be applied via the feed wheel against a tree trunk for clamping thereof is re¬ duced as compared with the case when the feed wheel is pro¬ vided with a rigid mantle. The reduced clamping force results in reduced timber damages and also entails a reduced fuel con- sumption of a machine provided with a harvesting arrangement having feed wheels of the type in question. By using a flexible mantle instead of a rigid mantle, the ability of the shock- absorbing layer to absorb impacts caused by protuberances and crookednesses of a fed tree trunk is also improved, which results in reduced strains on the other parts of the harvesting arrangement.

According to another preferred embodiment of the invention, the mantle is divided into two or more mantle parts which are mutu¬ ally separated from each other in the circumferential direction of the feed wheel, the respective mantle part being secured to the hub by means of fastening members, each of which extending between the hub and the associated mantle part through or at the side of the shock-absorbing layer, the respective fastening member being bendable or compressible so as to allow the mantle parts to be pressed down towards the hub. By the divid- ing-up of the mantle into separate parts, a good flexibility of the mantle is obtained in a simple manner, which will give the above-mentioned advantages. As indicated above, the fastening members relieve the pressure on the shock-absorbing layer with respect to torsional forces, whereby the risk that this layer will come loose from the hub is reduced. The fastening members will at the same time prevent an individual mantle part from being thrown away and causing personal injuries or material damages if the interconnection between the mantle part and the shock- absorbing layer would get lost.

Further preferred embodiments of the inventive feed wheel will appear from the dependent claims and the subsequent descrip¬ tion.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will in the following be more closely described by means of embodiment examples with reference to the appended drawings. It is shown in: Fig 1 a schematic, partly cut lateral view of a feed wheel ac¬ cording to a first embodiment of the present invention,

Fig 2 a cut according to U-Il in Fig 1 ,

Fig 3 a schematic perspective view of the feed wheel accord¬ ing to Figs 1 and 2,

Fig 4 a schematic perspective view of a feed wheel according to a second embodiment of the invention,

Fig 5 a schematic, partly cut lateral view of a feed wheel ac¬ cording to a third embodiment of the invention, and

Fig 6 a schematic perspective view of the feed wheel accord- ^" ing to Fig 5.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

A feed wheel 1 according to an embodiment of the invention is illustrated in Fig 1. This feed wheel 1 is intended for longitudinal feeding of elongated objects, such as tree trunks. The feed wheel comprises a hub 2, which in the illustrated example has the form of a circular cylindrical tube. The hub 2 is suitably made of metal, for instance in the form of sheet metal. A shock- absorbing layer 3 of elastic material is arranged around the hub 2, which layer has the form of a preferably circular cylindrical tube with a sufficient wall thickness to provide an efficient shock-absorbing function. This layer 3 is attached to the hub 2 and is with advantage formed of solid rubber. A mantle 4 is at¬ tached on the outside of the shock-absorbing layer 3. The mantle 4 and the shock-absorbing layer 3 are joined together. The mantle 4 extends essentially coaxially in relation to the hub 2 and is provided with several gripping members 5 on the out¬ side for gripping an object fed by means of the feed wheel. According to the invention, the mantle 4 is secured to the hub 2 by means of several fastening members 6, each of which ex¬ tending between the hub 2 and the mantle 4 through or at the side of the shock-absorbing layer 3. The fastening members 6 are distributed in the circumferential direction of the hub as well as in the axial direction of the hub. The fastening members 6 are arranged to allow the mantle 4 to be pressed down towards the hub 2 but to resist a parting of the mantle from the hub in radial direction. The respective fastening member 6 is bendable or compressible so as to allow the mantle 4 to be pressed down towards the hub 2 under compression of the intermediate shock- absorbing layer 3, i.e. against the action of the elastic force of the shock-absorbing layer. The respective fastening member 6 further has a sufficient tensile rigidity to prevent a parting of the mantle 4 from the hub 2 in radial direction. The respective fas¬ tening member 6 is fastened to the hub 2 and to the mantle 4, for instance by welding or via loops 11 arranged on the outside of the hub and on the inside of the mantle. The respective fas- tening members 6 could also be fastened to the mantle 4 via a hole or recess in the mantle.

In the embodiment illustrated in Figs 1 and 2, the feed wheel is provided with sixteen fastening members 6 of said type, which here extend through the shock-absorbing layer 3. Eight of these fastening members 6 are distributed around the hub 2 at a first axial end 8a of the hub and the remaining eight fastening mem¬ bers are distributed around the hub at the other axial end 8b of the hub.

In the embodiment illustrated in Figs 1-3, the mantle 4 has the shape of an essentially rigid tube. However, the mantle 4 is with advantage flexible. The desired flexibility of the mantle may for instance be achieved in that the mantle 4 has one or more parti- tion gaps 7 extending across the mantle in its axial direction. In this description and the subsequent claims, the expression "a partition gap extending across the mantle in its axial direction" refers to a gap which as seen in the circumferential direction of the mantle partitions off a mantle part from an adjacent mantle part by extending from one axial end 8a of the mantle to the other axial end 8b of the mantle. The two mantle parts which are adjacent to a partition gap have movability in relation to each other. The partition gap 7 may extend axially right across the mantle 4 in parallel with the centre axis of the feed wheel, as illustrated in Fig 4, but may also have another extension be¬ tween the axial ends 8a, 8b of the mantle.

In the embodiment illustrated in Fig 4, the mantle 4 is formed in one piece and has a partition gap 7 arranged between two ends 9a, 9b of the mantle facing each other. In this case, the mantle consequently has the shape of a tube which is split open in its axial direction. In this case, the mantle 4 is secured to the hub 2 in the manner described above with reference to Figs 1 and 2.

According to a particularly preferred embodiment, the mantle 4 is divided into two or more mantle parts 4a-4d mutually sepa¬ rated from each other in the circumferential direction of the feed wheel, for instance via partition gaps 7 of the above-indicated type. The respective mantle part 4a-4d is secured to the hub 2 by means of fastening members 6 in the manner described above with reference to Figs 1 and 2. Thus, the respective fas¬ tening member 6 extends between the hub 2 and the associated mantle part 4a-4d through or at the side of the shock-absorbing layer 3 and is bendable or compressible so as to allow the mantle parts 4a-4d to be pressed down towards the hub under compression of the intermediate shock-absorbing layer 3. Fur¬ thermore, the respective fastening member 6 has a sufficient tensile rigidity to prevent a parting of the associated mantel part 4a-4d from the hub 2 in radial direction. The respective fasten- ing member 6 is fastened to the hub 2 and to the associated mantle part 4a-4d, for instance by welding or via loops 11 ar- ranged on the outside of the hub and on the inside of the mantle part. The respective fastening member 6 could also be fastened to the associated mantle part 4a-4d via a hole or recess in the mantle part.

In the example illustrated in Figs 5 and 6, the mantle is divided into four mantle parts 4a-4d covering a respective sector of the cylinder-shaped envelop surface of the shock-absorbing layer. Fastening members 6 should be fastened at least to the four corner areas 10 of the respective mantle part 4a-4d. With ad¬ vantage, also further fastening members 6 are fastened to the respective mantle part in the area between these corner areas.

The individual mantle parts 4a-4d are with advantage mutually interconnected in the circumferential direction of the feed wheel by means of bendable holding members, not shown, each of which extending between two mantle parts 4a-4d located adja¬ cent to each other. The respective holding member may for instance be arranged to span the partition gap 7 between two mantle parts located adjacent to each other. The respective holding member is suitably an elongated and bendable element, such as a chain, a cord or a wire. The respective holding member is fastened to the associated mantle parts, for instance by welding, via loops arranged on the mantle parts or via holes or recesses in the mantle parts. The holding members help to prevent an individual mantle part 4a-4d from being thrown away and causing personal injuries or material damages if the interconnection between a mantle part and the shock-absorbing layer 3 would get lost. The holding members will also make possible a temporary continued use of the feed wheel if the interconnection between an individual mantle part and the shock-absorbing layer would get lost.

The shock-absorbing layer 3 is preferably made of rubber vul- canized to the hub 2 and to the mantle 4. Furthermore, the fas¬ tening members 6 are suitably vulcanized into this rubber. The in- ventive feed wheel is suitably produced by first assembling the hub 2, the mantle 4 and the fastening members 6, whereupon rubber dough is injected into the space between the hub and the mantle and thereafter vulcanized.

The respective fastening member 6 is suitably an elongated and bendable element, such as a chain, a cord or a wire. Alterna¬ tively, fastening members in the form of compressible telescopic rods could be used.

The mantle 4 is suitably made of metal, preferably in the form of sheet metal.

The hub 2 is suitably designed in such a manner that the feed wheel can be mounted onto the intended driving shaft by press¬ ing the hub onto the driving shaft, in which case the feed wheel when necessary can be removed from the driving shaft by pressing the hub away from the driving shaft. Alternatively, the hub may on the inside be provided with fastening members al- lowing the feed wheel to be screwed onto the driving shaft.

The gripping members 5 arranged on the mantle 4 may be of any suitable type. They are intended to give the mantle a grip, which is sufficient for the feeding, in the surface of the object, for instance in the envelop surface of a tree trunk, which is in¬ tended to be fed by means of the feed wheel, without causing unacceptable damages to the object. In the embodiment illus¬ trated in Figs 1-3, the feed wheel is provided with gripping members 5 in the form of ribs with sharp edges extending axially over the mantle. In the embodiments illustrated in Figs 4-6, the feed wheel is provided with gripping members 5 in the form of pins with sharp points distributed over the mantle. The gripping members 5 may of course also have other designs than those here illustrated. The invention is of course not in any way restricted to the pre¬ ferred embodiments described above. On the contrary, several possibilities to modifications thereof should be apparent to a person skilled in the art without departing from the basic idea of the invention as defined in the appended claims.

Claims

1. A feed wheel for longitudinal feeding of elongated objects, such as tree trunks, which feed wheel comprises a hub (2), a shock-absorbing layer (3) of elastic material arranged around the hub, and a mantle (4) attached to the shock-absorbing layer, the mantle (4) being provided with gripping members (5) on the outside for gripping an object fed by means of the feed wheel, characterized in that the mantle (4) is secured to the hub (2) by means of fastening members (6), each of which extending be¬ tween the hub and the mantle through or at the side of the shock-absorbing layer (3), the respective fastening member (6) being bendable or compressible so as to allow the mantle (4) to be pressed down towards the hub (2).

2. A feed wheel according to claim 1 , characterized in that the respective fastening member (6) is an elongated and bendable element, such as a chain, a cord or a wire.

3. A feed wheel according to claim 1 or 2, characterized in that the mantle (4) has the form of an essentially rigid tube.

4. A feed wheel according to claim 1 or 2, characterized in that the mantle (4) is flexible.

5. A feed wheel according to claim 4, characterized in that the mantle (4) has one or several partition gaps (7) extending across the mantle in its axial direction.

6. A feed wheel according to claim 5, characterized in that the mantle (4) is formed in one piece and has a partition gap (7) ar¬ ranged between two ends (9a, 9b) of the mantle facing each other.

7. A feed wheel according to claim 4 or 5, characterized in that the mantle (4) is divided into two or more mantle parts (4a-4d) which are mutually separated from each other in the circumfer¬ ential direction of the feed wheel, the respective mantle part (4a-4d) being secured to the hub (2) by means of fastening members (6), each of which extending between the hub and the associated mantle part (4a-4d) through or at the side of the shock-absorbing layer (3), the respective fastening member (6) being bendable or compressible so as to allow the mantle parts (4a-4d) to be pressed down towards the hub (2).

8. A feed wheel according to claim 7, characterized in that the mantle parts (4a-4d) are mutually interconnected in the circum¬ ferential direction of the feed wheel by means of bendable holding members, each of which extending between two mantle parts (4a-4d) located adjacent to each other.

9. A feed wheel according to claim 8, characterized in that the respective holding member is an elongated and bendable ele¬ ment, such as a chain, a cord or a wire.

10. A feed wheel according to any of the preceding claims, characterized in that the shock-absorbing layer (3) is of rubber.

1 1. A feed wheel according to claim 10, characterized in that the shock-absorbing layer (3) is vulcanized to the hub (2) and to the mantle (4).

12. A feed wheel according to claim 10 or 1 1 , characterized in that the fastening members (6) are vulcanized into the shock- absorbing layer (3).