DE3018985A1 - METHOD AND DEVICE FOR SAWING TREE TRUNKS IN SQUARE CUTS - Google Patents

Description

Description:

Method and device for sawing tree trunks into cuboid blanks.
5

Description;

The invention relates to a method for sawing naturally grown, conically tapered ones Tree trunks into elongated, essentially cuboid-shaped Blanks, in particular railway sleepers, as well as a device for carrying out this method.

Are naturally grown tree trunks tapering towards the tip in cuboid cuts, like e.g. beams, sleepers, planks with a given cross-section that is constant over the entire length of the blank sawn, it is known that the yield achieved is compared to the initial volume of the tree trunk relatively low. On the one hand, this is due to irregular

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in the growth of the tree trunk and on the other hand in the natural conical shape of the trunk, which is conical tapers towards the tip, while the desired end product, the blank, has a constant cross-section.

Finally, the small yield is also due to the fact that the cross-sectional area of the blanks is often quite good is large compared to the base of the tree trunk. Often only a cross-section of the end product fits into the round one Cross-sectional area of the tree trunk.

The object of the invention is to provide a method and a device operating according to this method for sawing To create naturally grown tree trunks that taper conically towards the tip, with which one is possible high yield of cuboid blanks can be achieved from the tree trunks.

This object is achieved in a method of the type mentioned in that at least two parallel, Cuts aligned with the geometrical longitudinal axis of the tree trunk are carried out, as well as through a Device for carrying out this method, characterized in that it has positioning means of the trunk and a saw with the at least

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two parallel cuts can be made, so that planks with a width of the desired cross-sectional dimension the thickness corresponding to the blank can be obtained.

The invention makes it possible to make one slimmer towards the tip to optimally divide the tree trunk into uniform, standardized, cuboid-shaped cuts that ensure a constant have a rectangular cross-section h χ 1. The invention enables a methodical exploitation of the permissible Tolerances of the standardized end product, in particular the tolerances with regard to edge rounding, side bevelling etc .. Overall, a significantly better volume yield is achieved.

For the description of the invention, reference is made in the following to railway sleepers. This product is in Structure and dimensions standardized, the standards allow certain tolerances with regard to beveling and rounded edges etc .. The inventive method and according to this Process-working devices can also be applied to other, essentially cuboid-shaped blanks such as beams, Planks, boards, etc. applicable.

The cross-section of a typical railway sleeper is 24 χ 14 cm, the length is 2.6o m, which is relative

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Large cross-section allows only low yields in tree trunks with a diameter of 30 - 70 cm. Normally the tree trunks that are sawn into railway sleepers by the timber industry do not have a larger one Diameter. The specified threshold cross-section 24 χ 14 cm excludes practically all tree trunks, their diameter is less than 30 cm.

With the cutting method according to the invention one becomes significant improved yield achieved for all trunk diameters. There can also be trunks with a diameter of less than 30 cm can be processed, the lower limit of the diameter is around 16-18 cm.

According to the invention, the tree trunk is made by parallel cuts te cut lengthwise into unedged planks with a thickness corresponding to the height h. With railway sleepers this height is h - 14 cm. The cuts can be made one after the other or at the same time (e.g. with gate saws) be performed.

The parallel cuts have a distance H from each other, the following applies: H - h + s, s - the thickness of the saw blade. The parallel cut surfaces are symmetrical to the geometrical longitudinal axis of the tree trunk, which is passed through the

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Centers of the two substantially circular end faces of the trunk wood runs, or this longitudinal axis lies in the cut surface.

The above-mentioned exemplary embodiment of the method according to the invention and the device used to carry out this method are explained in more detail below and described with reference to the drawing. In this show:
Io

Fig. 1: In the individual figures a - d plan views of a Tree trunk, namely on the smaller face of a tree trunk with the cutting plan drawn in,

Fig. 2: In the sub-figures a - d perspective representations of untrimmed, according to the cutting plans in Fig. 1 obtained planks with drawn cut surfaces,

Fig. 3 A: A front view of three marginal rinds of different sizes, as in the Cutting method according to Fig. 1 can be obtained,

Fig. 3 B: A perspective view of a rind

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according to Fig. 3 A,

FIG. 4: A perspective illustration of a rind according to FIG. 3B with the sectional plane drawn in for the hemming cut (above) and after success

tem hem cut (below),

Fig. 5a: A top view of one of several wedge stumps composite block,

Fig. 5b: An end view of the block according to Fig. 5a,

Fig.5c and d: front views of a section

Block according to Fig. 5a,
15th

Fig.6a: A front view of the right edge of an unedged Bohle to explain the method according to the invention,

6b: A representation corresponding to FIG. 6a with additional hydraulic scanning device shown,

Fig. 6c: A longitudinal section through a hydraulic cylinder

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the / piston unit for scanning according to Fig.

6b,

6d: A representation corresponding to FIG. 6b, but with an electrical scanning device,

7: A perspective illustration of a scanning device according to FIGS. 6b and 6d,

Fig. 8: Basic representations of the course of the edge

F 1 and F 2 of two untrimmed planks to explain a scanning device with three scanning points.

The two sectional plans mentioned above, i.e. symmetrical section or section along the longitudinal axis, are shown in Fig. 1 shown. The inner circle with annual rings limits the smaller, upper diameter of the Trunk, the outer circle limits the larger diameter. One could use the cut surfaces instead of, as shown, Lay parallel to the longitudinal axis of the tree trunk and parallel to an outer edge of the trunk. Have in this solution however, the cut pieces have more irregularities than the preferred one shown in FIG Procedure.

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In the case of tree trunks whose smaller diameter is sufficiently larger than the distance H between the cut surfaces, a symmetrical cut made with two cut surfaces. As a result, an untrimmed one is obtained as shown in FIG Plank with the thickness h. In the case of trunks with a smaller diameter sufficiently larger than 2 H, a middle cut is made executed with three cut surfaces according to Fig. Ib, this gives two untrimmed planks. For tree trunks where the smaller diameter is sufficient is greater than 3 H, again a symmetrical cut with 4 cut surfaces is carried out. You get corresponding to Fig. Ic three unedged planks. For trunks for which the smaller cross-sectional diameter is sufficient is greater than 4 H, a central cut with 5 cut surfaces is made. According to FIG. Id, four are obtained unedged planks. The same procedure is used for logs with a larger diameter.

Regardless of the diameter of the trunk, two outer rinds fall off. The profile of these rinds is a segment of a circle, the area of this circular segment increases in height and length from front to back in FIG. 1. Of the The reason for this is the conical shape of the trunk. The rinds and the unedged planks are different in the following Processed.

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In FIG. 2, untrimmed planks are shown as they are obtained in accordance with the four cutting plans in FIG will.

For unedged planks that are not wide enough to the desired standard product, thus in the example the "railway sleeper" to be obtained (see Fig. la) Adjustment and abbreviations carried out. These run essentially perpendicular to FIG. 1 a the end faces, they are as far apart as possible. These cuts make a piece of wood more constant Height h, but obtained with a linearly increasing cross-section. The two end faces are different rectangles Length, the top and bottom faces are trapezoidal in shape due to the conical shape of the trunk. The wood cut thus obtained is referred to below as the "wedge stump". In each case a wedge stump is obtained if one uses the Fig. 2b-d cuts the untrimmed planks.

In Fig. 2a an untrimmed plank is shown, the width of which is below the width of 1-24 cm for railway sleepers which is not sufficient for the production of the standardized product. Through the two regulatory cuts that have been drawn in a wedge stump is obtained. Fig. 2b shows an unedged plank with a width that the

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Making a threshold possible. As the figure shows, the sleeper is cut from the plank in such a way that that the greatest possible edge chamfer still lying within the tolerance limit is obtained. The corresponding, The vertical section on the right in FIG. 2b was therefore made as far outside as possible. Included however, the curvature of the tree trunk must be taken into account. The orientation of the plank before the cut is made made manually or by means of a device described later. This device enables an optimal Alignment of the screed so that the waste is as little as possible.

A truncated cone is obtained from the remainder shown on the left in FIG. 2b. For this purpose, the in Fig. 2b executed vertical section drawn on the left, which runs perpendicular to the base surface. This cut should produce sharp edges and be as far away from the central cut surface as possible. 2o

In Fig. 2c a plank is shown that is wide enough to produce two railway sleepers and a truncated cone. As the figure shows, the two thresholds are as far outside as possible, up to the permissible rind limit, been laid.

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In Fig. 2d a plank is shown that is wide enough to contain three sleepers and a wedge stump. Even here the thresholds have been placed as far outside as possible, up to the permissible rind limit.

The sawing method according to the invention thus allows 0-2 sleepers with a rind to be made from each untrimmed plank The number of square sleepers depending on the diameter of the tree and finally a wedge stump with one Length L, a thickness h and a width between 0 and 1.

In the saw plans according to FIG. 1, two slab boards are left over. Their cross-section corresponds to as already said, a section of a circle. The area of this circular segment increases according to the conical shape of the trunk. Furthermore, these slab boards have a curved outer surface with a substantially conical shape Curvature and a flat side, which was created by the outer cut according to FIG. 1. The slabs are now made by parallel cuts at right angles to the flat cut surface mentioned in Distributed lengthways. This is done with normal saws, for example circular or gang saws.

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In Fig. 3A, four parallel sawing surfaces are shown which are at a distance H from one another. Between The individual saw blades thus remain at a clear distance h, that of the required height h of the already cut, unedged planks. As in Fig.

3 A, these longitudinal sections are also shown according to the teaching of the invention, that is, either symmetrically to the trunk center axis (upper and lower part of figure in Fig. 3 A) or along the trunk center axis (middle part of figure). According to FIG. 1, the smaller of the two end faces is shown in FIG. 3A. The longitudinal sections are designed in such a way that one obtains bodies with the length L, the flat underside of which has the shape of a rectangle L χ h, the two opposite long sides of which have the shape of a trapezoid (due to the conical shape of the trunk) which are at right angles to the rectangle and which has a fourth, irregular longitudinal surface, that of the tree's curvature is equivalent to. Such a body is shown in Fig. 3B between two edge-side sections.

These bodies are referred to below as "cut rinds" and cut into wedge stumps, as described above and shown in FIG. The curved surface follows the trunk Page straightened by the curvature by means of a

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Saw is cut off or lifted off with a milling cutter, see Fig. 4. This gives a flat surface, which is at right angles to the two side surfaces. As shown in Fig. 4, the cut surface is as close as possible far from the flat rectangular surface.

In the sawing process described, the tree trunk was cut into five different types of wood. It are these the outer sections, material, that falls off when straightening the slab, wedge stumps and thresholds.

While the first three products are waste and can e.g. be used as fuel or otherwise, the latter two types represent high-quality products that are manufactured in standard dimensions.

The wedge stumps differ from the desired standard product, So from a railway sleeper, in that they do not have a constant cross-section, but one Have inclined surface. The length L and the height h, however, correspond to the required standard dimensions.

When cutting wood you have to cut as much as possible

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Make cuts in the direction of the grain, otherwise the mechanical behavior, especially the resistance, will differ locally Lich is and glues do not hold up sufficiently.

With the method described, deviations from the longitudinal direction of the fibers are obtained which are not greater than the deviations obtained after the known machining methods. One can therefore use the individual wedge stumps connect them to each other at their two large surfaces, thus obtaining a block of wood of width L, that of the corresponds to the original length of the tree trunk. The height h is equal to the height of the standard product, i.e. the Railway sleeper, the width B can be of any size, since you can connect any number of wedge stumps with each other can.

The direction of the wood fiber runs in the direction of the length dimension L and is retained when the wedge stumps are joined together. For this purpose, the wedge stumps are each placed next to each other that surfaces of the same inclination adjoin each other, so that, as shown in Fig. 5a, a substantially cuboid large block is obtained. This avoids that Can add up deviations in the grain direction.

In Fig. 5b is an end view of that shown in Fig. 5a

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composite body shown. As in Fig. 5a, the solid lines correspond to the connection points, The intersection lines are shown in dashed lines, the spacing of which is sufficiently large to produce products of the width 1, the length L and the height h.

The wedge stumps are connected to one another using the usual techniques, in particular by gluing. The mechanical pressure is applied using suitable devices, such as clamps. The gluing can be carried out continuously, i.e. one stump after the other, by working on one side of the block according to FIG. 5a and already makes separating cuts on the other side. On the other hand, can however, you can also glue a large number of wedge stumps at the same time by exerting pressure on the end faces and cut the block obtained in a later operation.

Is a full bevel of one or both side surfaces permissible for a standardized product, as is the case with, for example If this is the case with some railway sleepers, the separating cuts can deviate from vertical separating cuts 5b can also be carried out obliquely, as shown in FIGS. 5c and d, in order to obtain a higher number of pieces

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to be able to. In Fig. 5c a sectional diagram for the production of sleepers with double-sided bevels is shown. In Fig. 5d, the thresholds have one-sided inclination. The double, essentially vertical lines show the Cut surfaces, the simple, vertical, unbroken lines indicate the connection points.

In the manufacture of railway sleepers, which are referred to below, even if the inventive The method can be carried out for other standard products with essentially rectangular cross-sections, Edge rounding is generally permitted. The maximum limits for this edge rounding ("forest-edged") are defined by two maximum values of the deviation from the geometric, sharp edge. In doing so, a railway sleeper on the one hand the horizontal deviation and on the other hand the vertical deviation measured.

Sleepers with the standard dimensions, ie a height h and a width 1, can be made from the untrimmed ones shown in FIGS. 2b-d Planks are cut. The plank is first cut on the raw side, with a cut that runs at right angles to the base surface, but as far outside as with the resulting edge

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incline is compatible. For example, in Fig. 2c the vertical section of the right and left outside is so far outside as permitted within the tolerances. This achieves the greatest possible yield.

Only when these cuts have been made is the width 1 of the threshold measured and a threshold sawn off.

The same procedure was followed on the left-hand side of the untrimmed plank as shown in FIG. What remains is that medium wedge stump. The procedure for the widest of the disks shown in FIG. 2d is analogous. From this an inner, third threshold can be cut out, which does not have a beveled edge, it is sharp-edged. The same procedure is used for a plank that is so narrow that only a single threshold has been cut out can be, as shown in Fig. 2b. On the right side of the screed according to Fig. 2b, the vertical Cut as far to the right as permitted within the tolerance limits of the beveled edge. Afterward the threshold is cut as drawn. A third cut is made on the left side of the screed, which is as far to the left as possible, but the cut edges are sharp-edged. This is necessary since the wedge stumps must be sharp-edged.

This last, described type of cut is also on

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executed on both sides of a plank, as shown in Fig. 2a. The orientation of these cut surfaces can be done by eye by placing the piece of wood to be cut in relation to the cutting surface of the saw is aligned or by adjusting a movable saw to the desired cutting surface. For alignment control strokes that are projected onto the piece of wood to be sawed help.

However, the determination of the cut surfaces can also be done with With the aid of the device described below.

In Fig. 6a, the vertical cut surface of the saw is along the dashed line 0-B-C. The two horizontal, The dashed parallels fl and f2 correspond to the flat cut surfaces of the screed, they are spaced apart OC, which corresponds to the height h. The distance AO indicates the highest permissible horizontal deviation, as well the distance OB indicates the highest permissible vertical deviation. On the left in Fig. 6a is the naturally grown, untrimmed edge of a plank F shown.

The screed F is moved according to the direction of the wedge to the cutting line OBC until both deviations are within

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the tolerance limit, i.e. the horizontal deviation is less than or equal to AO and at the same time the vertical deviation is accordingly in the dimension OB. So it is not enough that the screed F during its displacement to the right with respect to the cut surface reaches, for example, the position X, in this case the horizontal one and the vertical deviation too high. It is also not sufficient that the plank F is in position Y (dashed shown), in which the horizontal deviation lies within the tolerance, the vertical deviation however it is still too high. Only in position Z (solid line) and in all other positions on the right However, in positions where material is wasted, the screed F is in a suitable position Cutting position. Position Z is the optimal cutting position. So it is a matter of making the plank F perpendicular to the Move the cutting plane until all three points A, B and C are at least reached according to the illustration above are.

In Fig. 6b, a hydraulic scanning device is shown with which the orientation of the screed F with respect to the Cut surface can be done. On points A, B and C, which in a favorable embodiment according to Fig. 6a vertikai are arranged one above the other, are scanning tips

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of piston rods of three hydraulic cylinder / piston units arranged. These cylinder / piston units are attached in accordance with FIG. 6b so that they are their Can not change position. In Fig. 6c, a cylinder / piston unit is shown in section. The piston rod 1 is held in the position shown by a spring 2. An outlet opening 3 is located immediately behind the rear surface of the piston, so that with a small backward movement against the force of the spring 2 the outlet opening 3 is blocked. Another opening 4 is on the rear wall of the cylinder intended. Fig. 6b shows the connecting lines between the outlet openings 3 and a hydraulic tank 5. The outlet openings 3 are connected in parallel, the openings 4 are connected to one another. The piston rod of each cylinder / piston unit can move back freely, the piston opening the inlet port 3 blocked and the oil through the lower opening 4 into another, with the hydraulic tank 5 in communication Cylinder is pressed. This is done through an outlet opening 3 that is still open. However, it is the last one The outlet opening 3 is blocked, the system is blocked and the screed F cannot be pushed any further to the right. It is then with respect to the fixed cutting surface in the best possible position to after

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Straightening cut to produce the maximum permissible edge rounding. If the vertical deviation extends over the entire vertical side face, points B and C coincide. Only two cylinder / piston units remain left over, the lower and the upper.

In Fig. 6d is another embodiment of a scanning device shown. The individual scanning elements A, B and C by electrical sensors, in particular Switch, formed. The working direction of these switches is coordinated with the direction of movement of the screed F. The switch A is closed by the upper edge of the upper, smooth surface of the plank F. as well the switch C is operated from the lower edge of the lower, flat surface of the screed F. The scanning element B is in Direction of forward movement of the screed F is moved until a switching process takes place, the switching rod can in this State can be pushed further to the right, but the electrical contact remains closed. Instead of mechanical switches can also be provided with light barriers etc., the only decisive factor is that an electrical one Contact is closed.

The electrical circuit is shown in Fig. 6d. The individual switches are arranged in series one behind the other.

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In contrast to the embodiment according to FIG. 6b blocked this scanning device does not allow the screed F to move forward. However, you have an electrical switch, which can switch on a separate blocking device, e.g. a clamp. This holds the plank F in the reached, optimal position when the screed F is advanced manually; the screed F is mechanical pushed to the right, the conveyor is switched off at the same time.

The devices described position the cutting line only on one end face of the screed F, for example on the smaller end face lying in front in FIG. 1. A second scanning device enables the cut to be optimally aligned even at the opposite end. Such a scanning device is shown in principle in FIG. The screed F is pushed manually in the direction of the arrow against two hydraulic scanning devices 6, which are each arranged in the vicinity of the end faces of the screed F. The two scanning devices 6 hold the screed F in the optimal cutting position. If you are working with a stationary saw, the plank F must then be pushed in the direction PT, which lies in the cutting plane. However, the plank F can also, without being moved, by a circular saw

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be cut, which is embedded in the table surface 7 or above this table surface in the direction PT is arranged displaceably. In this case, the scanning devices 6 are folded down on hinges 7 beforehand so as not to getting damaged.

In the device according to FIG. 7, the alignment takes place in that two edge regions of the untrimmed plank F are scanned will. With this method, however, it cannot be guaranteed that after the cut the side surface lies within the permitted tolerance along its entire length. For example, the tolerance can be in the middle Part of the screed F must be exceeded. Often, however, the measurement is sufficient, in two restricted areas, As in the case of railroad tracks, the standard dimensions specified in the area of rail fastening in particular must have. Advantageously, however, the points A, B and C can be arranged so that a Margin of safety is obtained. 2o

If, on the other hand, you want to examine more than two edge areas, the electrical or hydraulic ones used for this purpose can be used Scanning devices do not, as is the case with the device according to FIG. 7, operate independently of one another.

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With two scanning devices, the screed F is moved in the direction of the arrow until an edge area is scanned and held in the appropriate position. The movement of the screed F is continued with the first scanning device 6 acts as a joint until the edge on the second scanning device 6 is also in the optimum position has enough. If, on the other hand, you want to scan more than two edge sections, you must avoid the two first blocking scanning devices prevent the screed F from advancing further.

In FIG. 8, a schematic illustration is used to explain how three scanning devices arranged along the cutting line 14 are used to examine three edge regions. The planks F are thereby advanced in the direction of the arrow to the right, F ₁ and F ₂ are scanned, the edge lines of two, untrimmed Bohlen F. When the three sensing devices would operate independently, it may happen that the border lines F ₁ and F _n is as shown in the middle area of FIG. The edge at point Io on edge line F ₁ and the edge at point 2o on _{edge line F 2 have not been scanned.} The straightening resulting from line 14 would therefore be wrong.

What is required in such a device is in accordance with

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Fig. 8 so that the first responding scanning devices 6 do not block the screed F, but that one Edge-side scanning device, for example the scanning device at the scanning point 3o the screed F locally blocked and a movement with pivoting movement around this point 3o is made possible until all others Scanning devices, in this case at points Io and 2o, have been actuated.

Only the last actuated scanning device 6 may cause the screed F to be blocked, because only then ,, a cut within the tolerance limits is guaranteed. This is shown on the right in FIG. 8.

To achieve such a scan in a system in which η + 1 cross-sections are to be examined, it is sufficient to close one of the two peripheral scanning devices 6 from the other scanning devices separate to have a first stop. The other n devices are connected to one another in such a way that that none of these η-devices alone can bring about the final hold of the screed F, this is only possible, if the last scanning device 6 has also responded. In a scanning device accordingly Fig. 6b it is sufficient that the n devices by means of a

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common line, which connects the openings 4 in parallel, are connected to one another. Until all n-fixtures. gene have addressed, at least one outlet port 3 remains open, so that the hydraulic fluid in the Hydraulic tank 5 can flow out. Likewise, it is sufficient in the electrical version according to FIG. 6b η devices to be connected in series with one another. Until all contacts A, B and C of the η devices are closed the circle remains interrupted and the position of the screed F is not finally blocked.

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Claims (8)

Method and device for sawing tree trunks into cuboid blanks. Expectations: 1.) Method of sawing naturally grown oneself conically tapering tree trunks to elongated, essentially Io borrowed cuboid blanks, especially railway sleepers, characterized in that at least two parallel, on the geometric longitudinal axis of the tree trunk aligned cuts are made. 030050/0691 Telephone: (0221) 380238 Telegram: Inventato, Cologne Telex: 8883555 max d f'cstscheckkonto Cologne (BLZ 370 10050) Account No. 152251 -500 ■ Deutsche Bank AG Cologne (BLZ 37070060) Account no. 123618 1 2. The method according to claim 1, characterized in that the cuts in be carried out a distance that corresponds to a cross-sectional dimension of the blank. 3. The method according to claim 1 or 2, characterized in that the untrimmed planks obtained by these cuts are successively inserted into the desired, cuboid blanks and frusto-wedge-shaped ones Bodies are sawed which have two opposite, trapezoidal side surfaces and which are on their other longitudinal surfaces are connected to one another in such a way that a body of sufficient width is formed, which can be sawn into the desired blanks. 4. Device for performing the method according to one of claims 1 to 3, characterized in that it has means for positioning the log (scanning device 6) and one Has saw with which at least two parallel cuts can be carried out, so that planks (F) with one, the width the desired cross-sectional dimension of the blank corresponding thickness can be obtained. 5. Apparatus according to claim 4, 030050/0691 characterized in that it is at least one, the positioning of the planks (F) within the specified tolerances for edge rounding, beveling etc. enabling scanning device. 6. Apparatus according to claim 5, characterized in that the scanning device (6) has at least two scanning elements (e.g. at A, B and C), which are connected to a common, hydraulic circuit, in contact with the untrimmed Edge of the plank (F) come and block when the edge of the plank (F) has reached a position that is inside the maximum permissible bevel. 7. Apparatus according to claim 6, characterized in that the scanning elements are designed as cylinder / piston units, their Piston rods (1) carry out the scanning and one of the pistons can be locked with a hydraulic tank (5) connected outlet opening (3) and a line connected to a plurality of cylinder / piston units common Have opening (4). 8. Apparatus according to claim 5,
characterized in that the scanning 030050/0691 organs have electrical switches (at A, B and C), which can be actuated from the edge surface of the moving screed (F) and are connected in series so that the actuation of the last switch determines the cutting position. 030050/0691