EP0744255A2 - Device for cutting up logs and milling head for such a device - Google Patents

Abstract

The machine has one or more pairs of opposite driven cutter heads (6), each with two rings of chopping blades, and associated cutting saws. The rotation diameters of the chopping blades (14,18) of the two rings (12,16) are relatively adjustable. The active width of the blades in the rings with smaller diameters, is adjustable for side definition of the outer, more narrow of the two side planks to be cut. The rotary axis (10) of the cutter heads extends parallel to the cutting planes of the associated saws. The chopping blades in one ring are offset relative to those in the other ring.

Description

The invention relates to a device for cutting logs into wood products according to the preamble of claim 1 and a milling head suitable for this.

A generic device is described for example in DE-C-29 28 949. This device has i.a. Milling heads with chopping knives, the cutting edges of which produce a cylinder jacket when rotating and which therefore run parallel to the rotational axis of the head. The milling heads are intended to cut out tree-edged corner areas from a tree trunk, which already delimit side boards on the trunk, which are then cut off using a separating saw. In a particular embodiment, step milling cutters can also be used as milling heads according to the cited document, with which two parallel corner folds can be milled out at the same time, which then delimit two side boards in a paired arrangement and are separated by means of separating strips.

According to DE-C-29 28 949, the width and depth of the corner folds to be worked out is determined exclusively by the position of the milling head in relation to the tree trunk to be processed. When using a step mill, one of the corners to be milled can be determined by the depth of the tool, but the dimensions of the second corner are determined in relation to the first corner by the dimensions of the tool, ie by the dimensions of its chopping knife ring of smaller diameter. Should the width and thickness of the narrower, outer side board regardless of the limitation of the wider, inner one Side board can be changed, so this is only possible with two separate milling heads working in series, each carrying a cleaver and the depth of immersion in the workpiece can be adjusted independently.

The invention has for its object to provide a device of the type mentioned that has two mirror-image milling heads for the narrow-sided limitation of side boards to be separated on one side of a tree trunk, each of which is adjustable so that the thickness and width of the outer side board to be separated independently are adjustable from the dimensions of the inner side board.

This object is achieved in principle by the characterizing features of claim 1.

If the device is to be used to produce side boards that have roughly the same finishing condition on all sides, then the cleaver knives must each be assigned finishing tools that can be reworked on the surface of the worked corner that is exposed from the side end of the cleaver and forms an angle with the cutting edges of the cleaver. Such a procedure is described in DE-C-29 18 622. If the method explained there is to be used optimally in the subject matter of the invention, the drive shafts of the corner milling cutters are to be aligned in such a way that they run parallel to the cutting planes of the cutting saws.

In particular, the invention also relates to a step milling head for the claimed device, as described in claim 3 and in a special, further embodiment in the subclaims following claim 3.

Even if other arrangements are fundamentally possible, the claimed device is to be described in the following with reference to an embodiment in which the cutter head pairs rotate about vertical shafts and the cutting edges of the chopping knives run essentially vertically and describe a cylinder jacket with a vertical axis. The milling heads of a pair are essentially mirror images in the vertical direction and can therefore be driven by a common, vertical drive shaft. A tree trunk to be processed moves horizontally through the device, so that the mutual spacing of the milling heads of a pair determines the width in the vertical direction of at least the wider of the two side boards to be delimited. The immersion depth of the pair of milling heads in the horizontal direction determines the common thickness of both side boards. This immersion depth is generally adjustable in the horizontal direction of the entire tool unit carrying both milling heads and their drive. With a common drive shaft for a pair of milling heads, the mutual vertical spacing of the milling heads can be adjusted by their mutual displacement on the shaft.

If, in the context of the present description, in particular with regard to the tools, in particular the knives, one speaks of orientations which only have to be “essentially” given, this restriction takes into account the fact that knife edges, even if they are given a basic orientation is often slightly inclined to allow a softer or increasing intervention in the workpiece.

As already mentioned at the beginning, the width of the inner, wider side board closer to the trunk axis and the thickness of both side boards to be limited are determined jointly by the depth of immersion of the milling heads in the tree trunk in vertical and horizontal directions. Once this position is given, the ratio in which the thickness of the entire side goods to be separated is divided into the thickness of the inner and outer side boards, determined by the difference in the rotational diameter of the chopping knife ring of larger diameter and the chopping knife ring of smaller diameter. Since the difference is important here, it is fundamentally possible to either change the rotation diameter of the chopping knife ring of larger diameter in relation to the rotation diameter of the chopping knife ring of smaller diameter or vice versa. If the radius of the chopping knife ring of larger diameter is selected for a change in diameter, the immersion depth of the entire tool must of course be changed accordingly in the horizontal direction in order to remain at the same side fabric thickness. The amount by which the outer board is narrower on each side than the inner side board is determined by the effective width of the cutting edges of the chopping knife ring of smaller diameter. This effective width is essentially the projection that the chopping knives of the smaller diameter ring have in the vertical direction over the vertical extent of the chopping knives of the larger diameter ring on one side. This protrusion is kept variable according to the invention in order to vary the width of the outer side board relative to the inner side board in that the chopping knives of the ring of smaller diameter can be brought into different overlap with the chopping knives of the ring of larger diameter, whereby they have an effective width due to the area of this overlap lose, because in the overlap area the chopping knives of the wreath of larger diameter have a larger working radius, so that the knives of the wreath of smaller diameter do not come into effect here. In order to allow such an overlap of the rotating surfaces of the two chopping knives, it is structurally expedient to arrange the chopping knives of both rings in their circumferential positions offset from one another, so that in the carrier body at those points where the chopping knives of the ring have a smaller diameter during their axial adjustment in the Carrier body Enter more or less, no construction space for attaching the cleaver of the wreath of larger diameter is needed.

The adjustability of the chopping knives of a knife ring individually or overall compared to the other knife ring can be carried out in different ways. One possible adjustability is by means of displaceability of the knives or their knife carriers along complementary, linear profiles and by mutual jamming by means of, for example, clamping screws in a certain position. Such a design is suitable for manual knife adjustment. However, it is also possible to provide adjusting means which can be operated remotely in the carrier body of the milling head, such as, for example, motor-driven eccentrics, spindle drives or other gears, but also hydraulic drives. Methods of supplying the required energy and the required signals via rotary unions on the drive shafts are available in the prior art.

The discussion of further advantageous refinements of the invention is to take place in the following with the aid of a single milling head.

Basically, according to the invention, it is possible to carry out both adjustment directions on one of the two chopping knife rings of a milling head, and preferably on the chopping knives of the ring of smaller diameter. The fact that the rotational diameter of the two chopping knives need only be changeable relative to one another offers the possibility of providing the adjustment of the mutual radial distance of the chopping knives from the axis of rotation on the chopping knives of the wreath of larger diameter, while for changing the effective width of the chopping knives of the wreath of smaller diameter, the adjustment of which is provided with respect to the carrier body, in that the chopping knives of the ring of larger diameter are then arranged immovably in the axial direction.

In such an embodiment, for example, the chopping knives of the ring of smaller diameter can be arranged in a separate carrier element which, as a whole, is designed to be more or less submersible in the carrier body, so as to ensure that the axially protruding edges of the knife rings of smaller diameter over the ends of the cutting edges of the knife ring larger diameter to be able to change together. Such an embodiment would be suitable, for example, for a hydraulic adjustment drive.

However, if you choose the way to provide both adjustabilities individually on the chopping knives of the wreath of smaller diameter, this can be done for each chopping knife, for example, by means of a cross-slide guide, the play of which can be adjusted in both directions by suitable locking means for the individual case. For example, it is possible to attach the knife carrier carrying the actual chopping knife to a knife support that extends essentially in the axial direction so that it can be displaced in approximately the radial direction, while the knife support itself is slidably arranged in an axial guide in the carrier body.

It has already been mentioned above that for the fine machining of the (in relation to the arrangement described) horizontally aligned boundary surface of each worked corner on the milling head additional fine machining tools can be provided. For the corner worked out by the chopping knife ring of larger diameter, such finishing tools are to be arranged in the radial boundary plane between the two chopping knife rings. Here, saw blade segments are available as fine machining tools, which can be arranged in the circumferential space between the usually only two chopping knives provided for a ring. In order to be able to keep the circumferential extent of such saw blade segments as large as possible, it is expedient to circumferentially the cleaver heads of both rings to be arranged offset from one another, but not too far apart, so that a corresponding circumferential space remains available for the arrangement of the saw blade segments. If such saw blade elements are provided for the fine machining of a surface of the corner worked out by the chopping knife ring of larger diameter, it is advisable not to provide the relative adjustability of the radial distance of the knife rings from one another in the knife ring of larger diameter, since otherwise a corresponding radial adjustment would have to be provided for the saw blade segments.

Additional fine machining tools can also be provided for the fine machining of one surface of the corner worked out by the chopping knife ring of smaller diameter. If the chopping knives of the ring of smaller diameter are also embedded in an essentially ring-shaped element, as is customary with the chopping knife ring of larger diameter, saw blade segments could also be used as finishing tools for the ring of smaller diameter. The restrictions regarding radial adjustability would also apply here.

If both adjustabilities are provided in the chopping knives of the ring of smaller diameter, it is advantageous to provide finishing knives as finishing tools, which are provided on the knife carriers for the chopping knives of the ring of smaller diameter, since with such an attachment they also carry out a radial adjustment of these chopping knives. These finishing knives are additional knives, the cutting edge of which essentially runs in a radial plane, that is to say in a plane that extends perpendicular to the knife edges of the cleaver.

In order to produce wood chips that can be recycled as industrially as possible with milling heads of the type discussed here, the number of chopping knives preferably kept relatively small in a knife ring and generally consists of only two cleavers. This minimum number is to be observed simply for reasons of rotational symmetry and mass balancing.

Fig. 1

einen schematisch dargestellten Teilbereich aus einer Vorrichtung zum Verlegen von Baumstämmen, der zwei Fräskopfpaare zeigt, die sich in eckenausarbeitendem Eingriff mit einem bereits vierseitig angeflachten Stamm oder Model befinden, und

Fig. 2

in perspektivischer Darstellung einen Fräskopf aus der Anordnung gemäß Fig. 1 mit zwei Hackmesserkränzen, die relativ zueinander verstellbar sind.

In the following, the invention will be explained in more detail with reference to a special embodiment with reference to the accompanying drawings. In the drawings:

Fig. 1

a schematically shown section from a device for laying tree trunks, which shows two milling head pairs, which are in corner-working engagement with a trunk or model already flattened on four sides, and

Fig. 2

a perspective view of a milling head from the arrangement shown in FIG. 1 with two chopping knives, which are adjustable relative to each other.

In the partial view of a device for cutting tree trunks into wood products shown in FIG. 1, a tree trunk 2 is shown in cross section, which is already flattened on four sides. From the rectangular cross section, it can be deduced that side boards were already laterally delimited in the same way on the top and bottom of the trunk and then subsequently separated, as will be explained below for the left and right sides of the tree trunk 2. The tree trunk 2 is supported by a support element 4 and moves through the device in a direction perpendicular to the plane of the drawing.

A pair of milling heads 6 is shown on each side of the tree trunk 2. The two milling heads 6 of a pair are each rotatably driven by a common shaft 8, the axis of which is in each case the axis of rotation 10 of a milling head 6. The waves 8 are with (not provided) rotary drives. The relative distance between a pair of milling heads 6 in the vertical direction is possible by moving the milling heads 6 on the shaft 8 in opposite directions. The means for adjusting the milling heads in the vertical direction and for locking the milling heads in a specific distance setting are not shown in detail.

Each milling head 6 has a ring 12 of chopping knives 14 of a larger diameter and a ring 16 of chopping knives 18 of a smaller diameter. The only partially visible cutting edges of all chopping knives 14 and 18 run in the illustrated embodiment in a substantially vertical direction in or parallel to the plane of the drawing.

It can be seen that the chopping knives 14 each mill an inner corner 20 of the trunk profile and the chopping knives 18 mill an outer corner 22 as the tree trunk 2 moves perpendicular to the plane of the drawing. It can also be seen that the size and position of the inner corners 20 is determined by the immersion depth of the milling heads 6 as a whole in the vertical and horizontal directions in the tree trunk. The formation of the outer corners 22, on the other hand, depends on the dimensions and position of the chopping knives 18 of the knife ring 16 of smaller diameter in relation to the position and the dimensions of the chopping knives 14 of the knife ring 12 of larger diameter.

In order to be able to change the size and position of the outer corners 22 to be milled out, the chopping knives 18 of the knife ring 16 of smaller diameter are themselves adjustable relative to the milling heads 6. Further details are explained using the exemplary embodiment of a milling head according to FIG. 2.

The cutter head 6 shown in perspective in FIG. 2 has a carrier body 24 of essentially hollow cylindrical shape, in the circumference of which the cleavers 14 of the Cleaver of larger diameter are embedded. The chopping knives 14 are each fixed in the carrier body 24 by means of a screwed-in knife holder 26 and a pressure plate 28 screwed against it.

The lower edge 30 of the carrier body 24 shown in FIG. 2 does not come into contact with the tree trunk, as can easily be seen from the lower milling heads in FIG. 1. It can therefore have a somewhat larger diameter for stiffening.

In the event that, in contrast to the representation in FIG. 1, the upper and lower sides of the tree trunk have not yet been processed, the vertical penetration depth of the chopping knives 14 of the chopping knife ring of larger diameter is variable over the length of the tree trunk because of the taper of the tree trunks. The vertical penetration depth of the chopping knives 18 of smaller diameter, on the other hand, remains constant because it is in constant relation to the lower horizontal surface of the inner corner 20. Because of these relationships, the cutting of the chopping knives 14 of the outer ring is made correspondingly longer.

Reference is now made again to FIG. 2. The ring of chopping knives of smaller diameter also has two diametrically opposed chopping knives 18, which, however, are slightly offset in their circumferential position with respect to chopping knives 14 of the ring of larger diameter. The chopping knives 18 are clamped against knife carriers 34 by means of pressure plates 32. These knife carriers 34 are designed to be adjustable in two mutually perpendicular directions, namely on the one hand in the axial direction of the milling head and in the substantially radial direction of the milling head.

Each knife holder 34 itself is clamped by means of screws 36 against a knife support 38, on which it is loosened after the screws 36 have been loosened by means of radial T-slot guides is displaceable and can be locked in different positions by the screws 36.

The knife supports 38 are in turn arranged in axial guides (not visible in the drawing) within the carrier body 24. The knife supports 38 can be locked in different axial positions by means of a clamping block 40 and screws 42. As can be seen from FIG. 2, the knives 18 dip into the carrier body through openings 44 in the event of an axial displacement in the direction of the carrier body 24, so that their projection beyond the upper edges of the cleaver 14 of the ring of larger diameter can be changed. With the section with which the knives 18 dip into the openings 44, they are not effective. Their effective length is only their protrusion beyond the upper edge of the cleaver 14. This projection determines the vertical depth of the outer corners 22 in FIG. 1.

Saw blade segments 46 are provided on the upper side of the carrier body 24 of the milling head between the chopping knives 18 of the smaller diameter ring, which can be adjusted in two directions, based on the illustration in FIG. 2. These saw blade segments make a saw cut along the horizontal surfaces of the inner corners 20 according to FIG. 1. Thus, the vertical surfaces of the inner corners 20 are machined by cutting the chopping knives 14 and the horizontal surfaces by the saw blade segments 46.

Correspondingly, the adjustable chopping knives 18 of the small diameter ring of knives are assigned finishing knives 48. These finishing knives are fastened to the outer edge of the knife carrier 34 in such a way that their cutting edges run approximately in the tangential direction of the chopping knife ring of smaller diameter. They serve the same purpose as the saw blade segments 46. Because the finishing knives 48 on the knife carriers 34 are attached, they carry out all the adjustment movements of these knife carriers, so that they always remain in the same relative position to the cleaver 18 and each finish or finish the horizontal surfaces of the outer corners 22 in FIG. 1.

The chopping knife 18 of the small diameter knife ring in the milling head shown in FIG. 2 is adjusted by hand. To carry out a precise setting, it is expedient to briefly remove the milling head from the device and place it in a correspondingly set teaching in which the loosened chopping knives 14 can then be clamped in a precise position in a new position. An adjustment of the chopping knife 18 by suitable automatic adjustment means is also possible.

The milling head according to the invention makes it possible to manage with half the number of milling head drives in a system in which step corners are to be carved out of a tree trunk or to significantly reduce the storage of a plurality of differently dimensioned tools.

Claims (17)

Device for cutting logs into wood products with at least one pair of opposing milling heads, each driven with a ring of at least two chopping knives, the cutting edges of which run essentially parallel to the axis of rotation, for the lateral limitation of two side boards of different widths to be separated and to be separated, on one Side of the tree trunk by milling out two parallel tree-edged corner strips, the cutting edges of the two chopping knife rings lying on different rotational diameters and the chopping knives being suitable for producing wood chips from the corner material to be worked out, and
with each pair of milling heads assigned cutting saws to separate these two side boards,
characterized by at least one pair of milling heads (6) according to one or more of claims 3-17, in which the rotational diameter of the chopping knives (14 or 18) of the two chopping knife rings (12, 16) is adjustable relative to one another and the effective width of the chopping knife ( 18) which is adjustable in the pair of milling heads (6) opposite chopping rings (16) of small diameter for lateral limitation of the outer, narrower of the two side boards. Device according to claim 1, characterized in that the axis of rotation (10) of the at least one pair of milling heads (6) runs parallel to the cutting planes of the associated cutting saw means. Milling head for milling tree-edged corner strips in a device for cutting tree trunks into wood products according to claim 1 or 2,
with a support body (24) which can be fastened to a drive shaft and rotatable about an axis of rotation and which is provided on its outer circumference with two rings (12, 16) of at least two chopping knives (14, 18) each for producing chips from the material of the corner strips to be milled out , whose cutting edges, which run essentially parallel to the axis of rotation (10), describe two imaginary, essentially cylindrical surfaces of rotation with different diameters,
characterized in that the chopping knives (14, 18) at least one of the chopping knife rings (12, 16) can be adjusted with their cutting edges in their radial distance from the axis of rotation (10) in the carrier body (24), for changing the diameter of one of the rotating surfaces in relation to the other, and
the overhang of the cutting edges of the chopping knife ring (16) of smaller diameter can be changed in the axial direction beyond the axial extent of the cutting edges of the chopping knife ring (12) of larger diameter, in order to set a desired effective width of the cutting edges of the chopping knife ring (16) of smaller diameter. Milling head according to claim 3, characterized in that the chopping knives (14, 18) of one chopping knife ring (12, 16) are arranged offset with respect to their circumferential position relative to the chopping knives (18, 14) of the other chopping knife ring (16, 12). Milling head according to claim 3 or 4, characterized in that the chopping knife ring of smaller diameter with firmly clamped chopping knives and the chopping knife ring of larger diameter with Chopping knives are provided, in which the radial distance of the knife edges from the axis of rotation is adjustable. Milling head according to claim 5, characterized in that the chopping knives of the chopping knife ring of smaller diameter are arranged jointly on a carrier element which can be more or less submerged in the axial direction in the axial direction and can be locked in different submerged positions in the carrier body. Milling head according to claim 3 or 4, characterized in that the knife carriers (34) of the chopping knives (18) of the chopping knife ring (16) of smaller diameter are individually guided on the carrier body (24) in the manner of a cross slide and can be locked in different positions of the cross slide-like guides. Milling head according to claim 7, characterized in that each knife carrier (34) of the chopping knife ring (16) of smaller diameter can be moved in the radial direction on a substantially axially extending knife support (38) and can be locked to it by clamping means (36). Milling head according to claim 8, characterized in that each knife support (38) is slidably guided in the axial direction in a knife head guide in the carrier body (24) and can be locked there by clamping means (40, 42). Milling head according to at least one of claims 3-9, characterized in that the carrier body (24) on the end face of the chopping knife ring (16) facing small diameter Chopping knife ring (12) of large diameter is provided with finishing tools for machining that area of the corner (20) worked out by the chopping knife ring (16) larger diameter, which forms an angle with the cutting edges of the chopping knives (14) of the ring (16) larger diameter. Milling head according to claim 10, characterized in that the fine machining tools are saw blade elements (46). Milling head according to claim 10 or 11, characterized in that the fine machining tools are arranged in the circumferential spaces between the chopping knives (14, 18). Milling head according to at least one of claims 3-12, characterized in that the chopping knife ring (16) of small diameter is provided on its end face facing away from the chopping knife ring (12) of large diameter with finishing tools (48). Milling head according to claim 13, characterized in that the finishing tools are finishing knives (48), the cutting edges of which lie essentially in a radial plane. Milling head according to claim 14, characterized in that the finishing knives (48) are attached to the free end faces of the knife carriers (34) of the chopping knife ring (16) of smaller diameter. Milling head according to at least one of claims 3-15, characterized in that the adjustable chopping knives (18) are designed for manual adjustability. Milling head according to at least one of claims 3-15, characterized in that the adjustable chopping knives are provided with adjustment drives.

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