Milling body

Abstract

The invention relates to a milling body (1) for milling wood, having a rotary body (2) that is assigned an axis of rotation (3) and has a lateral surface (5) extending around the axis of rotation (3), wherein a saw chain (6) extending around the axis of rotation (3) is arranged on the lateral surface (5), said saw chain having a plurality of chain links (7) with saw teeth (8), wherein the lateral surface (5) has a guide device (9) via which the saw chain (6) is guided on the lateral surface (5).

Description

[0001] Milling body

[0002] The invention relates to a milling body for milling wood, with a rotating body to which an axis of rotation is assigned and which has a shell surface running around the axis of rotation.

[0003] Milling machines driven by a motor for milling wood, for example for cutting off branches from a tree trunk, are known.

[0004] DE 38 18 174 C2 discloses a branch cutter with a support rod, which has a drive motor at one end and a cutter body coupled to it for cutting off branches. The cutter body has a small diameter in order to produce only a low moment of resistance when cutting through the branches. However, the document does not disclose any details on the construction of the cutter body.

[0005] A disadvantage of known milling bodies for milling wood, for example branches, is that their coarsely structured milling surface can result in an unclean cut and great resistance when cutting into a piece of wood, such as a branch, whereas a finely structured milling surface increases the time required to remove large quantities of wood, such as when removing a branch, to an undesirable level. A further disadvantage of known milling bodies is that they have blades which have to be mounted in complex and heavy (steel) supports, which makes the entire milling body very heavy. The blades are expensive to purchase and increase maintenance costs. Other known milling bodies have to be replaced after a certain period of use due to wear.

[0006] It is an object of the invention to create a milling body as initially stated which avoids or at least reduces the disadvantages of the prior art. In particular, the milling body should enable efficient milling of a piece of wood, for example branch stumps. In addition, the milling body should be simple, cost-effective, and robust. Furthermore, the milling body should be designed to be durable. This object is achieved by a milling body according to claim 1. Advantageous embodiments and further developments are specified in the dependent claims.

[0007] The invention is characterized in that a saw chain which runs around the axis of rotation and has a large number of chain links with saw teeth is arranged on the outer surface, the outer surface having a guide device by means of which the saw chain is guided on the outer surface. The milling body is thus provided for milling wood. For example, a tree can be worked on by milling using the milling body. In particular, the milling body can be provided for milling off branch stumps from a tree trunk as completely as possible. For this purpose, the milling body has a rotating body which is assigned a rotating axis. For milling wood, the milling body and thus also the rotating body are set in rotation. For this purpose, the rotating body can have a rotating shaft or be connected to at least one rotating shaft or have a receptacle, for example a recess or a through-opening, into which a rotating shaft can be inserted.The rotating shaft generally coincides with the axis of rotation. The rotating body also has a circumferential surface running around the axis of rotation. The circumferential surface is generally rotationally symmetrical about the axis of rotation. In order to be able to carry out an efficient milling process with the milling body and to make the milling body durable, a saw chain running around the axis of rotation is arranged on the circumferential surface. The saw chain has a large number of chain links with saw teeth. The saw chain is arranged on the circumferential surface in such a way that the saw teeth protrude from the circumferential surface. In particular, the saw teeth can protrude from the circumferential surface at a right angle to the axis of rotation. A saw chain designed for commercially available chainsaws can be used as the saw chain for the milling body, for example.In order to be able to replace worn saw chains or to regrind blunt saw chains, the saw chain is preferably arranged on the outer surface in a removable manner. This means that after a large number of milling operations, in particular in the case of damaged or blunt saw teeth, the entire milling body does not have to be replaced. The outer surface also has a guide device via which the saw chain is guided on the outer surface. The guide device can be designed to fix the saw chain in a predetermined, essentially rigid position with respect to the outer surface. For this purpose, the guide device can have a clamping device, for example. The guide device can further be designed to provide the saw chain with a degree of freedom for movement relative to the outer surface. The degree of freedom preferably runs in the direction of the longitudinal extent of the saw chain.For this purpose, the guide device can, for example, comprise a sliding device in which the saw chain is adjustably accommodated. The saw chain, once brought into a preferred position, can then be releasably or permanently fixed in this position. The guide device can extend at least along a longitudinal section, in particular along at least 50%, particularly preferably along at least 90%, of the length of the saw chain.

[0008] When reference is made in the course of the description to location and direction specifications such as "top", "bottom", "front", "back" or "side", these specifications refer to the intended use of the milling body, in which it engages a piece of wood. The term "vertical" means in the direction of gravity, from "top" to "bottom", or vice versa. If the milling body is to be used in a different position, the location and direction specifications must be transferred accordingly.

[0009] According to a preferred embodiment of the invention, a groove is formed as a guide device in the lateral surface, in which groove the chain links are at least partially received. Thus, the position of the saw chain can be predetermined by the groove and the saw chain can be held in place by the groove in at least one direction. The saw chain can be held in the groove in a fixed position with respect to the groove or displaceable along the groove. For example, the chain links can have an extension which is received in the groove.

[0010] In particular, if the extension of the rotating body in the longitudinal direction of the rotational axis is at least twice the width of the saw chain, it can be provided that the saw chain is guided helically around the rotational axis via the guide device on the outer surface and in particular the groove is helical. In general, the guide device can also be helically designed around the rotational axis. The helical course requires at least half a rotation around the rotational axis, but preferably at least one rotation around the rotational axis. The helical course of the saw chain ensures, at least in sections, a continuous, i.e. gap-free milling process between the ends of the saw chain, wherein at any time during the rotation of the rotating body at least one saw tooth of the saw chain can engage in the part of the wood to be milled off, for example a branch stub.

[0011] If the guide device, in particular the groove, has a substantially constant pitch, the rotating body can be manufactured particularly cost-effectively and lightweight, for example, from plastic. Furthermore, this enables a consistent milling performance, i.e., a consistent amount of material removal per unit of time, along the rotation axis. The pitch of the guide device, in particular the groove, is the distance traveled by the guide device or groove with exactly one rotation in the direction of the rotation axis.

[0012] Preferably, the pitch of the guide device, in particular of the groove, is in the range of 1.2 to 2 times the width of the saw chain. Such a constant or varying pitch enables the saw chain, which is arranged helically around the rotation axis on the outer surface, to be deflected in the longitudinal direction of the rotation axis using commercially available chainsaw chains. Special saw chains with joints for larger deflections in the lateral direction, i.e., in the longitudinal direction of the rotation axis, are therefore unnecessary. Furthermore, the pitch in the aforementioned range enables efficient material removal.

[0013] The rotating body preferably has two end faces facing away from one another and spaced apart from one another, between which the lateral surface is arranged. The end faces facing away from one another, or opposite one another, and spaced apart from one another can be partially open and, for example, have openings which form an outer end of a receptacle for the rotating shaft. The end faces are preferably formed with a circular circumference. The lateral surface which supports the saw chain is provided between the end faces. Further components of the milling body can be mounted on the end faces.

[0014] If the guide device, in particular the groove, viewed in a longitudinal section, extends along at least 50%, preferably at least 70%, particularly preferably at least 90% of the distance between the two end faces in the direction of the axis of rotation and if in particular the guide device, in particular the groove, begins at one of the end faces and ends at the other end face, the saw chain can be guided particularly reliably by the guide device, in particular the groove. In addition, such a wide arrangement of the guide device, in particular the groove, and in particular the saw chain accommodated therein, enables a correspondingly wide milling surface. If the guide device or groove begins at one of the end faces and ends at the other end face, the saw chain can be attached to the end faces in a simple manner.

[0015] Furthermore, it can be provided that the outer surface is curved inwards towards the axis of rotation or outwards away from the axis of rotation. The outer surface provided between the end faces can thus be curved inwards towards the axis of rotation / outwards away from the axis of rotation or, if the rotating body has a rotating shaft or is connected to it, in particular can be curved inwards towards the rotating shaft coinciding with the axis of rotation / away from the rotating shaft. The curvature of the outer surface can have the shape of a section of a circular circumference or a section of a circumference of an ellipse. The shape of the curvature can be suitably determined depending on the shape of the piece of wood to be milled.

[0016] In order to orient the saw teeth in the same direction, it is advantageous if, in a state with a horizontal axis of rotation, the curved outer surface, viewed in a longitudinal section, has a step-shaped contour with horizontal step surfaces and vertical step surfaces, and the groove is formed in the horizontal step surfaces. Preferably, this means that all of the saw teeth accommodated in the groove are arranged at a right angle to the longitudinal extent of the axis of rotation. The saw teeth can therefore engage in the piece of wood to be milled in their intended orientation. In addition, a force occurring during milling acts on the saw teeth in the direction of the groove and the axis of rotation, thereby preventing the saw teeth from tilting in the groove. The said longitudinal section is understood to mean a section with a plane in which the axis of rotation runs.

[0017] According to a further embodiment, a tensioning device connected to the rotating body can be provided, which is connected to the saw chain. By means of the tensioning device, the saw chain arranged on the outer surface can be tensioned and held in a tensioned state, thereby preventing movements of the saw chain that could cause damage to the saw chain itself or to the rotating body during operation of the milling body. During tensioning, the saw chain is subjected, in particular, to tensile stress.

[0018] The tensioning device preferably has at least one tensioning lever which can be pivoted about a pivot axis and has two lever ends on either side of the pivot axis, one lever end engaging the saw chain and the other lever end engaging an adjusting element, in particular a tensioning screw. In the case of two tensioning levers, one lever end of each of the tensioning levers can engage the saw chain and the other lever end of each of the tensioning levers can engage one of two adjusting elements. If the at least one adjusting element is actuated, for example the tensioning screw is turned, the tensioning lever can be pivoted about its pivot axis, as a result of which the lever end connected to the saw chain is also pivoted and the saw chain is tensioned or released.The adjustable clamping screw can, for example, be screwed into a through hole having an internal thread and connected to the rotating body.

[0019] For a particularly stable construction of the milling body, it can be provided that a preferably annular outer wall is mounted on at least one of the end faces, preferably on both end faces of the rotating body. The outer wall can be made of plastic or metal and preferably prevents breakage of the rotating body, in particular of the end faces, even in the event of high mechanical stress on the milling body. The outer wall can be non-destructively detachable or permanently connected to the end face, for example glued to the end face, snapped onto the end face, or screwed to the end face. If the outer wall is annular, a rotary shaft can be inserted through the annular opening in the outer wall.

[0020] For a particularly stable construction of the milling body, it can further be provided that the at least one tensioning lever of the tensioning device and preferably also the adjusting element, in particular the tensioning screw, are mounted on the at least one annular outer wall. In this way, the front side of the rotating body is not or only slightly stressed by the forces acting on the tensioning lever and the adjusting element during tensioning of the saw chain and in the tensioned state of the saw chain.

[0021] The invention is further explained below with reference to preferred embodiments, to which it is not intended to be limited. The drawings show:

[0022] Fig. 1 shows a section of a milling body which is designed as a milling drum, without an annular outer wall, in a perspective view, with a saw chain shown only in sections;

[0023] Fig. 2 shows a milling body which is designed as a milling drum, with annular outer walls, in a side view looking at one of the outer walls, with a clamping lever of the clamping device in a first position;

[0024] Fig. 3 shows the milling drum from Fig. 2 in a front view, with a saw chain shown only in sections; Fig. 4 shows the milling drum from Fig. 3 in a sectional view along the section line AA;

[0025] Fig. 5 is an enlarged view of detail C from Fig. 4;

[0026] Fig. 6 shows the milling drum with annular outer walls, in a side view looking at one of the outer walls, with the clamping lever in a second position which is different from the illustration in Fig. 2;

[0027] Fig. 7 shows a section through the clamping device shown in Fig. 6 along the section line DD;

[0028] Fig. 8 is an enlarged view of detail E from Fig. 7;

[0029] Fig. 9 shows a section of an interior view of one of the outer walls, without the saw chain;

[0030] Fig. 10 shows the section of the interior view of one of the outer walls according to Fig. 9, with the saw chain;

[0031] Fig. 11 shows a milling body which has a disk as a rotating body with a saw chain on the peripheral edge of the disk, in a simplified representation;

[0032] Fig. 12 shows a milling body which has a roller-shaped rotating body with a cylindrical outer surface and with a saw chain thereon, in a simplified representation;

[0033] Fig. 13 shows a milling body which has a cylindrical rotating body with an outwardly curved surface and with a saw chain thereon, in a simplified representation; and

[0034] Fig. 14 a milling body which has a cylindrical rotating body with a truncated cone-shaped outer surface and with a saw chain thereon, in a simplified representation.

[0035] It should be noted that Figures 1 to 14 are not necessarily drawn to scale. Fig. 1 shows part of a milling body 1, which is designed, by way of example, as a milling drum for milling wood, for example branch stumps (not shown) or other parts of a tree trunk. The milling body 1 has a rotating body 2, which is assigned a rotation axis 3 (see also Fig. 4). The rotating body 2 also has a circumferential surface 5 running around the rotation axis 3. In the example shown, the rotating body 2 also has two end faces 4, 4a, 4b facing away from and spaced from one another, between which the circumferential surface 5 is arranged, in the example shown a circumferential surface 5 curved inwards towards the rotation axis 3. Arranged on the circumferential surface 5 is a saw chain 6 which runs around the rotation axis 3 and has a plurality of interconnected chain links 7 with saw teeth 8.For example, the saw chain 6 is arranged in a helical configuration on the outer surface 5. In Fig. 1, the saw chain 6 is only shown in sections, and the chain links 7 are only shown connected to one another in a small section in order to provide a view of the underlying outer surface 5 in the larger section. Of course, however, all chain links 7 of the saw chain 6 are connected to one another. The outer surface 5 has a guide device 9 (see, for example, Figures 1, 3, 4, and 5), via which the saw chain 6 is guided on the outer surface 5. In particular, the guide device 9 is designed as a groove 10 in the outer surface 5, in which groove 10 the chain links 7 are at least partially received and guided. For this purpose, an extension 11 of the chain links 7 can be received in the groove 10 (see Figs. 5 and 8).By means of the guide device 9, in particular groove 10, the saw chain 6 is protected from slipping sideways in the axial direction of the rotation axis 3, i.e., in the longitudinal direction L of the rotation axis 3. The chain links 7 preferably rest on the outer surface 5 on both sides of the groove 10 in order to be able to transfer the forces occurring when milling wood to the outer surface 5 over as large an area as possible. The depth of the groove 10 can be, for example, 2 mm to 10 mm, and the width of the groove 10 can be, for example, 1 mm to 5 mm.

[0036] In particular, Figs. 1 and 3 show that the saw chain 6 is guided helically around the rotation axis 3 via the guide device 9 on the outer surface 5 and in particular the groove 10 is helically formed.

[0037] In Figs. 1, 3 to 5, 7, and 8, the rotating body 2 is shown with a lateral surface 5 that is curved inward toward the rotation axis 3. In the example according to Fig. 13, however, the rotating body 2 is shown with a lateral surface 5 that is curved outward away from the rotation axis 3.

[0038] 1 and 3, among others, show the rotating body 2 with a horizontally arranged axis of rotation 3. It can be seen that in this state with a horizontal axis of rotation 3, the curved outer surface 5, viewed in a longitudinal section, has a stepped contour with horizontal stepped surfaces 12 and vertical stepped surfaces 13, and the groove 10 is formed in the horizontal stepped surfaces 12, see also Fig. 8. Although no longitudinal section of the curved outer surface 5 with a vertical plane is shown in Figs. 1 to 10, the stepped contour with horizontal stepped surfaces 12 and vertical stepped surfaces 13 can be easily understood from Figs. 1 and 3. Since the groove 10 is formed in the horizontal stepped surfaces 12, the saw chain 6 can be prevented from lateral tilting, which could otherwise occur due to the forces acting when milling wood.

[0039] In particular, it can be clearly seen from Figs. 3, 4, and 5 that the guide device 9, in particular the groove 10, has a substantially constant pitch 14, at least along an axial section between the end faces 4. Preferably, the pitch 14 of the guide device 9, in particular of the groove 10, is in the range of 1.2 to 2 times the width B of the saw chain 6, in particular of the chain links 7.

[0040] It is particularly preferred that the guide device 9, in particular the groove 10, viewed in a longitudinal section of the rotating body 2, extends along at least 50%, preferably at least 70%, particularly preferably at least 90% of the distance X between the two end faces 4 in the direction of the axis of rotation 3. In the illustrations according to Figs. 1, 3, and 4, the guide device 9, in particular the groove 10, begins at one of the end faces 4, 4a and ends at the other end face 4, 4b.

[0041] Figs. 2 and 6 to 10 each show a part of a tensioning device 15 connected to the rotating body 2, which is connected to the saw chain 6. The tensioning device 15 serves to tension the saw chain 6. Figs. 2 and 6 clearly show that the tensioning device 15 has at least one tensioning lever 17 pivotable about a pivot axis 16, with two lever ends 18, 18a, 18b on either side of the pivot axis 16. In Figs. 2 and 6, only one tensioning lever 17 is visible. One of the lever ends 18, 18a engages the saw chain 6, in particular with a chain link 7, see Fig. 8. The other of the lever ends

[0042] 18, 18b engages with an adjusting element 19, in particular with a clamping screw 19a, shown only symbolically. In the example according to Fig. 2, the clamping screw 19a is screwed into an internally threaded through-hole 20 of a web 21 of the clamping device 15. In the example according to Fig. 6, the clamping lever 17 was pivoted by turning the clamping screw 19a, compared to the example according to Fig. 2.

[0043] While Fig. 1 shows the milling body 1 without an outer wall connected to the end faces 4, in the examples according to Figs. 2 to 10, a preferably annular outer wall 22 is mounted on at least one of the end faces 4, preferably on both end faces 4 of the rotating body 2. The outer wall 22 serves to reinforce the milling body 1 and preferably has a central opening 23 through which a rotary shaft (not shown) can be inserted. The at least one clamping lever 17 of the clamping device 15 and preferably also the adjusting element

[0044] 19, in particular the tensioning screw 19a, are mounted on the at least one annular outer wall 22. The outer wall 22 also has, for example, a wall opening 24 through which a pin 25 protrudes, which is arranged on the lever end 18, 18a connected to the saw chain 6. The pin 25 preferably engages in the saw chain 6, in particular in a chain link 7 or a saw tooth 8, see in particular Figs. 8 and 10. By means of the pin 25, the force from the tensioning lever 17 can thus be transmitted to the saw chain 6. Fig. 9 shows an interior view of a section of the annular outer wall 22, with the pin 25 protruding through the wall opening 24 at the lever end 18, 18a, wherein the saw chain 6 is not shown for the sake of clarity. In Fig. 10, the saw chain 6 is shown in comparison to Fig. 9.The inner side 26 of the outer wall 22 can have a ramp-shaped recess 27 in the region of the wall opening 24, the depth of which continuously decreases in the longitudinal direction of the saw chain 6. In this way, the saw chain 6 can be continuously guided from the wall opening 24 out of the outer wall 22 onto the lateral surface 5.

[0045] For the sake of clarity, adjacent chain links 7 and saw teeth 8 are shown connected to each other only in a small section in Figs. 1 and 10; see the hatched connecting elements. Furthermore, the saw chain 6 is shown only in a simplified form in Figs. 1, 3 to 5, 7, 8, and 10 to 14, e.g., without the joints connecting the chain links 7.

[0046] Fig. 11 symbolically shows an example of a rotating body 2, which is designed as a disk, with the saw chain 6 arranged on the peripheral edge of the disk, which forms the lateral surface 5. In this example, the saw chain 6 does not run helically, i.e., without a pitch, around the rotation axis 3.

[0047] Fig. 12 symbolically shows an example of a rotating body 2, which is designed as a roller with a cylindrical outer surface 5. The saw chain 6 arranged on the outer surface 5 runs helically around the rotation axis 3.

[0048] Fig. 13 symbolically shows an example of a rotating body 2, which is designed as a roller with a circumferential surface 5 curved outwardly away from the rotation axis 3. The saw chain 6 arranged on the circumferential surface 5 runs helically around the rotation axis 3.

[0049] Fig. 14 symbolically shows an example of a rotating body 2 which is designed as a roller with a truncated cone-shaped outer surface 5, ie the diameter of the rotating body 2 decreases in the longitudinal direction L of the axis of rotation 3. The saw chain 6 arranged on the outer surface 5 runs helically around the axis of rotation 3. The rotating body 2 designed as a roller can, for example, have a length in the direction of the axis of rotation 3 in the range from 5 cm to 40 cm, a largest diameter in the range from 10 cm to 20 cm and a smallest diameter in the range from 5 cm to 15 cm.

[0050] The distance between adjacent saw teeth 8 arranged one behind the other along the saw chain 6 can be, for example, 1 mm to 5 mm.

[0051] In an embodiment not shown, the rotating body 2 can also be designed without flat end faces 4, 4a, 4b, for example as a sphere, a rotational ellipsoid, or generally with curved end surfaces emanating from the axis of rotation 3.

[0052] The milling body 1 can also have more than one saw chain 6 on the outer surface 5, for example two or three saw chains 6.

Claims

Patent claims:

1. Milling body (1) for milling wood, with a rotating body (2) which is assigned a rotation axis (3) and which has a casing surface (5) running around the rotation axis (3), characterized in that a saw chain (6) running around the rotation axis (3) is arranged on the casing surface (5), which saw chain has a plurality of chain links (7) with saw teeth (8), the casing surface (5) having a guide device (9) via which the saw chain (6) is guided on the casing surface (5).

2. Milling body (1) according to claim 1, characterized in that a groove (10) is formed as a guide device (9) in the lateral surface (5), in which the chain links (7) are at least partially received.

3. Milling body (1) according to claim 1 or 2, characterized in that the saw chain (6) is guided helically around the axis of rotation (3) via the guide device (9) on the lateral surface (5) and in particular the groove (10) is helically formed.

4. Milling body (1) according to claim 3, characterized in that the guide device (9), in particular the groove (10), has a substantially constant pitch (14).

5. Milling body (1) according to claim 3 or 4, characterized in that the pitch (14) of the guide device (9), in particular of the groove (10), is in the range from 1.2 times to 2 times the width (B) of the saw chain (6).

6. Milling body (1) according to one of claims 1 to 5, characterized in that the rotating body (2) has two end faces (4, 4a, 4b) facing away from one another and spaced apart from one another, between which the lateral surface (5) is arranged.

7. Milling body (1) according to claim 6, characterized in that the guide device (9), in particular the groove (10), viewed in a longitudinal section, extends along at least 50% of the preferably at least 70%, particularly preferably at least 90% of the distance (X) between the two end faces (4, 4a, 4b) extends in the direction of the axis of rotation (3) and in particular the guide device (9), in particular groove (10), begins at one of the end faces (4, 4a, 4b) and ends at the other end face (4, 4a, 4b).

8. Milling body (1) according to one of claims 1 to 7, characterized in that the outer surface (5) is curved inwards towards the axis of rotation (3) or outwards away from the axis of rotation (3).

9. Milling body (1) according to claim 2 and 8, characterized in that in a state with a horizontal axis of rotation (3), the curved outer surface, viewed in a longitudinal section, has a step-shaped contour with horizontal step surfaces (12) and vertical step surfaces (13), and the groove (10) is formed in the horizontal step surfaces (12).

10. Milling body (1) according to one of claims 1 to 9, characterized in that a clamping device (15) connected to the rotating body (2) is provided, which is connected to the saw chain (6).

11. Milling body (1) according to claim 10, characterized in that the clamping device (15) has at least one clamping lever (17) pivotable about a pivot axis (16) with two lever ends (18, 18a, 18b) on either side of the pivot axis (16), wherein one lever end (18, 18a) is in engagement with the saw chain (6) and the other lever end (18, 18b) is in engagement with an adjusting element (19), in particular with a clamping screw (19a).

12. Milling body (1) according to claim 6, characterized in that a preferably annular outer wall (22) is mounted on at least one of the end faces (4, 4a, 4b), preferably on both end faces (4, 4a, 4b) of the rotary body (2).

13. Milling body (1) according to claim 11 and 12, characterized in that the at least one clamping lever (17) of the clamping device device (15) and preferably also the adjusting element (19), in particular the clamping screw (19a), on which at least one annular outer wall (22) is mounted.

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