EP0489256B1 - Apparatus for slicing thin boards - Google Patents

Abstract

A machine for severing a board, by means of cutting, from a squared timber (14) which is advanced in its longitudinal direction against a cutter (12) and is pressed against the cutter from the side facing away from the cutter by means of a pressure device (18) and against a counterpressure rail mounted upstream of said cutter is described. In contrast to conventional designs in which the driven feed rollers for the squared timber are arranged in front of and behind the actual cutting device, according to the invention driven feed-roller pairs (32a/34a) are provided directly in the extension region of the cutter forming a very acute angle with the feed direction of the timber. In addition, the feed-roller pairs are mounted in a floating manner, so that they do not influence the position of the squared timber. As a result of the novel arrangement, an excessively long force-transmission path through the squared timber itself, from the feed rollers to the cutter, is avoided. <IMAGE>

Description

The invention relates to a device for producing thin boards by cutting the boards from a log or squared timber without cutting according to the preamble of claim 1. The invention particularly relates to means for feeding the squared timber in such a device.

A device of the type concerned is already described in the older DE-OS 37 02 909 or in the corresponding EP-OS 0277591 by the same applicant.

When cutting boards from a squared timber, it is important that the squared timber is guided correctly along the knife, with relatively high forces being exerted for pushing the squared timber against the knife, which are applied, for example, by push rollers firmly pressed against the squared timber are located in front of and / or behind the actual cutting device, which is passed through by the squared timber.

The forces exerted by the feed rollers on the squared timber should not interfere with the correct guidance of the squared timber in the cutting device along the knife, which is why it was already proposed in the aforementioned DE-OS 37 02 909 to float the pressure rollers in pairs in the transverse direction to the feed path of the squared timber store so that a pair of feed rollers can exert a high clamping force on the squared timber, but the clamping force does not exert an offsetting influence on the squared timber transverse to its feed path. This measure was intended to ensure that the pressure of the squared timber on the knife and the latter assigned counter pressure bar can be set and held at the desired height during cutting without being disturbed by the feed forces.

When cutting a squared timber into thin boards, which are further processed, for example, into solid wood laminate products, it is desirable to completely divide a squared timber into such thin boards without leaving an excessive residual board that can no longer be processed. It has now been shown that in the case of residual squared timber, from which several boards have already been cut off, the optimum cutting conditions on the knife can no longer be exactly maintained, despite the feed rollers arranged in front of and behind the actual cutting device and floating. This may be due to the fact that an already largely processed squared timber no longer has sufficient inherent stability to absorb the feed forces in such a way that it does not affect the cutting area.

Investigations have shown that a squared timber can still be satisfactorily completely divided into thin boards of essentially constant quality if feed forces are applied to the squared timber directly in the cutting area, but which are not produced by one-sided pressure.

The invention therefore provides that at least one pair of feed rollers is arranged in that region of the feed path over which the knife extends. So that the feed forces do not influence the pressure of the squared timber on the knife in any way, the or the directly in Feed roller pairs arranged in the knife extension area are preferably designed to be floating in the manner already proposed in DE-OS 37 02 909 for feed rollers arranged outside the cutting area of the machine. Since the arrangement of pairs of feed rollers on slides that are movable transversely to the feed path of the wood can be structurally difficult in this area, it is preferred here to design the feed rollers with the application of force by fluid cylinders, the cylinder spaces of which are in flow connection with one another in pairs.

In principle, it would be possible to arrange pairs of feed rollers in such a way that the axes of the rollers run perpendicular to the cutting plane, so that the feed rollers thus engage the squared timber from the sides of the opposing cutting and pressing device. Such a solution could offer constructive advantages, since the feed rollers do not have to intervene directly in the knife area or the area of the pressure device, but this design has the disadvantage that the contact surfaces available on the remaining square timber for the feed rollers decrease continuously with increasing processing of the square timber and the rest of the square timber in the transverse direction can no longer be robust enough to absorb the feed forces.

It is therefore generally necessary to arrange the axes of the feed rollers parallel to the cutting plane so that the feed rollers always have the same contact surface on the square timber. However, this solution can result in spatial difficulties.

A typical machine for the cutting production of boards from a squared timber is constructed, for example, in such a way that the knife and cutting plane lie horizontally, the counterpressure rail upstream of the knife edge being part of a support table which supports the squared timber in front of the knife from below, while the pressing device the squared timber from above against the support table and presses the knife.

In order to produce as little distortion as possible of a board cut off by means of the knife, the cutting edges of machines of the type concerned here are generally arranged at a very acute angle, for example less than 45 °, to the feed path of the squared timber. This acute angle extends the extent in which the knife is in engagement with it along the feed path of the squared timber, but at the same time it makes it difficult to arrange additional feed elements in the area of the knife.

In a preferred embodiment, the invention therefore provides in such a machine that the feed rollers arranged on the knife side of the squared timber of the respectively provided feed roller pairs are overhung on one side, namely on the side of the machine to which the knife edge points. The feed rollers mounted in this way engage in recesses which are provided in the support table but end shortly before the actual counter pressure bar. Accordingly, these feed rollers have a different axial extent, which decreases from the inlet area of the knife to the outlet area of the knife, the free ends of the feed rollers approximately form a line that runs parallel to the knife edge or the counter pressure rail. It has been shown that with a sufficiently stable construction with such knife-side feed rollers, sufficient feed forces can be applied to the square timber in this area.

The pressure device, which can be pressed and pressed against the square timber on the side facing away from the knife, has, for example, a series of pressure rollers which can be individually pressurized by means of a fluid cylinder. These pressure rollers can be wrapped together by a circumferential pressure belt, the working strand of which rests on the squared timber and moves with it. The pressure-side feed rollers of the pairs of feed rollers are expediently arranged opposite the knife-side feed rollers in the sequence of the pressure rollers, but their pressure controls are to be completely independent of the pressure rollers and are subject to the paired floating control with their counter rollers, as has already been described. The storage of the feed rollers on the side of the pressure device generally presents no particular design difficulties. On the fly, it can also be done on both sides.

Particularly in the case of the feed rollers arranged in the cutouts of the support table on the knife side, it is important that these do not exert any resulting transverse force on the squared timber which could tend to lift the squared timber off the support table. Rather, that of the Pressure device applied pressure on the squared timber and thus the pressure of the squared timber against the support table and the knife from the feed rollers to be completely unaffected.

In order not to have to apply the feed forces for the squared timber solely from the feed rollers arranged in the knife extension area, feed roller pairs are expediently also arranged at the machine entrance and at the machine exit, as already described in DE OS 37 02 909.

The description of the invention is based here on a single knife and its extent. The features according to the invention can of course also be applied to any further cutting device and each additional knife which is located in the same machine or in a machine arrangement which has a succession of several cutting devices. Likewise, the pressure device opposite a knife on the other side of the squared timber can also be designed in the form of a knife arrangement. The arrangement and configuration of the feed rollers described here as preferred for the knife side of the device then applies to each of the knife devices on both sides of the squared timber.

Fig. 1

eine schematische Seitenansicht einer Vorrichtung zum schneidenen Erzeugen von Brettern aus einem Kantholz,

Fig. 2

eine schematische Draufsicht auf die Vorrichtung nach Figur 1, bei der jedoch aus Klarheitsgründen obere Teile der Vorrichtung weggelassen sind, und

Fig. 3

einen Vertikalschnitt entlang der Ebene A in Figur 2.

A preferred embodiment of the invention is explained in more detail below with reference to the accompanying drawings. In the drawings:

Fig. 1

2 shows a schematic side view of a device for cutting boards from a squared timber,

Fig. 2

2 shows a schematic top view of the device according to FIG. 1, in which, however, upper parts of the device have been omitted for reasons of clarity, and

Fig. 3

a vertical section along the plane A in Figure 2.

The schematic side view of a device for cutting boards from a square timber without cutting in FIG. 1 has a machine base 2 in which a support table arrangement 4 is mounted in a height-adjustable manner. For the purpose of height adjustability, the support table arrangement 4 is mounted on sliding columns 6. The drive for the height adjustment is not shown in detail and can consist, for example, of an electric motor-driven spindle drive. Furthermore, a knife carrier arrangement 8 is provided in the machine base 2, which can be better seen in FIG. 3. This knife carrier arrangement itself can also be designed to be height-adjustable, but a separate height adjustment of the support table arrangement and knife carrier arrangement is not necessary, as long as it is ensured that the height of the support table can be adjusted relative to the knife carrier. The top of the support table arrangement 4 is designed as a flat support table 10. The knife carrier arrangement also has an upper contact surface 12. The support table 10 as such and the support surface 12 can best be seen in FIG. 2.

A squared timber 14 can be moved in its longitudinal direction along a feed path, which is indicated by arrows 16, over the support table 10 and the support surface 12 of the knife carrier arrangement is. The squared timber 14 can be pressed against the support table 10 and the support surface 12 of the knife carrier arrangement 8 by means of a pressure device 18. The pressure device 18 is supported in parts of the machine base 2, which, however, are not shown in the drawings. The pressure device 18 has an endlessly rotating pressure belt 20, which is guided at the ends of the device around deflection rollers 22, which can also be driven. A row of pressure rollers 24 is arranged above the lower run of the pressure belt 20, which abuts the squared timber 14. The suspension of these pressure rollers 24 in the pressure arrangement 18 is only indicated schematically. Each of the rollers 24 can be pressed against the pressure belt and thus the squared timber by means of a fluid cylinder 26. The connection between the cylinders 26 and the pressure rollers 24 is only shown by dash-dotted lines of action. For the purpose of pressure, the pressure rollers themselves are mounted in essentially horizontal pivoting levers within the pressure device 18, so that the roller itself is provided with a certain vertical freedom of movement.

The height distance between the pressure device 18 and the support table or the support surface of the knife carrier arrangement 8 must be changeable in order to be able to be adapted to different thicknesses of the squared timber 14. The entire pressure device 18 is therefore generally adjustable in height in the machine base 2. It is set to a certain thickness before the passage of a square timber, while when the square timber enters the space between the support table and the pressure device, the pressure rollers are then subjected to pressure are applied, which in turn are movably supported within the pressure device. It should be emphasized that the pressure rollers 24 do not have a rotary drive, since the rollers 24 only serve to press the pressure belt 20 against the squared timber 14.

In Figure 2 it can be seen that the support table 10 and the support surface 12 of the knife carrier arrangement lie opposite one another with parallel edges 28 and 30 which form an acute angle with the direction of the feed path 16 or the axis of the square timber 14 to be processed, which is even far below Is 45 °. The edge 28 of the knife carrier arrangement is the cutting edge of the knife clamped in this arrangement, the exact arrangement and type of clamping of which is not explained in the context of this description. The edge 30 of the support table has a counter-pressure rail (not shown in detail) which is raised slightly from the surface of the support table and essentially serves to prevent the wood from splitting when a board is cut off by the knife. In relation to the top view of FIG. 2, the knife edge 28 is somewhat higher than the edge or counter pressure rail 30 of the support table. This difference in height essentially determines the thickness of the board to be produced. If the squared timber is moved from the right against the knife edge 28, a board is separated from the squared timber, which is carried off obliquely laterally below the support surface 12 of the knife carrier arrangement 8. It can be clearly seen that the knife edge 28 extends through a very acute angle to the feed path 16 alone in its length, in which it engages with the square timber 14, over a not inconsiderable length section of the feed path 16.

To feed the squared timber 14, three pairs of feed rollers 32/34 are provided in the extension area of the knife 28. Each pair consists of a lower feed roller 32, which is arranged below the square timber 14, and an upper feed roller 34, which is exactly opposite the lower feed roller above the square timber and the like. is arranged within the pressure belt 20. This arrangement is best seen in Figure 1. In any case, the lower feed rollers 32 of the pairs 32/34 are themselves driven. A drive for the upper feed rollers 34 can be omitted if the deflection rollers 22 of the belt 20 are driven accordingly. It is essential, however, that the feed rollers can be pressed against the square timber 16 by means of only partially indicated fluid cylinders 36, the cylinder spaces of the fluid cylinders of a pair of feed rollers being in flow communication with one another via a line 38, as indicated for the feed roller pair 32a / 34a in FIG. 3 is. It can thus exert a high clamping force by a pair of feed rollers on the square timber 14, but the exact vertical position of the pair of feed rollers is not influenced by these pressing forces and is determined solely by the square timber, the vertical movements of which the pair of feed rollers follow due to the floating design.

It can be seen from FIG. 2 that the lower feed rollers 32a, b, c are supported on one side and engage in recesses 40 in the support table 10. Their ends extend close to the counter-pressure rail 30 or the knife edge 28, with different axial lengths because of the oblique course of the knife have, so that the connecting line of its free ends runs approximately parallel to the knife 28. The respective upper feed rollers 34a, b, c, as can be seen from the example of the upper feed roller 34a in FIG. 3, can be supported on both sides and provided with 2 fluid cylinders 36 for pressurization in order to achieve a stable distribution of the pressure force. The fluid cylinders 36 of each upper feed roller 34 are also in flow communication with one another.

From Figure 1 it can be seen that the upper feed rollers 34 are arranged in the sequence of the pressure rollers 24 and the like. in such a way that in the area in which the feed rollers 34 are located, a feed roller 34 alternates with a pressure roller 24. This exchange arrangement is intended to ensure that, despite the provision of the upper feed rollers 34, the pressure of the squared timber against the knife is still ensured with sufficient pressure distribution over the length of the knife. It should be emphasized again that the pressure rollers 24 alone press the squared timber 14 against the knife, while the pairs of feed rollers 32/34 clamp the squared timber firmly between them and move them forward by the drives, but in contrast to the pressure rollers 24 their vertical height can be freely moved is.

As can further be seen from FIGS. 1 and 2, further feed roller pairs 42 to 48 are provided in the feed area of the device and in the take-off area of the device, ie in front of and behind the knife arrangement. These pairs of feed rollers, which are already described in detail in DE OS 37 02 909, are used in the present arrangement essentially for the feed work of the roller pairs 32/34 and for the insertion of the squared timber into the machine and the last withdrawal of the squared timber from the machine.

The pressurization of the pairs of feed rollers is automatically controlled by control devices (not shown). These control devices can consist of photocells, for example. As long as there is no squared timber in the machine, the feed rollers as well as the pressure rollers must be relieved of pressure. It is recognized by photocells that the leading end of a squared timber has passed a pair of feed rollers in order to then immediately apply pressure to them. Similarly, pressure must be relieved again shortly before the trailing end of a square timber leaves a pair of feed rollers.

Claims (7)

1. Apparatus for producing thin boards by severing the boards in a chipless manner from a log or piece of squared timber (14), with a feed path (16) for the squared timber (14), a cutting device (4, 8), which is arranged on one side of the feed path (16) and comprises a cutter (28), which is either rigid or can be made to swing, for severing a respective board, a counterpressure rail (30), which is disposed before the cutter (28), whose distance from the cutting edge (28) transversely to the feed path (16) of the squared timber (14) essentially determines the thickness of the board to be severed and which is part of a support table (10), which may be vertically adjustable relative to the cutter (28), for the squared timber (14), the cutting edge (28) and the counterpressure rail (30) forming an acute angle with the feed path (16) of the squared timber (14), with a pressure device (18), which is disposed opposite the cutting device (4, 8) on the other side of the feed path (16) and which can be pressed from above against the squared timber (14) and thus against the opposite cutting device (4, 8), and with a feed means (32/34), which advances the squared timber (14) towards the cutter (28) of the cutting device along the feed path and comprises at least one pair of feed rollers (32a/34a), which grip the squared timber (14) at opposite sides and clamp it between them, characterised in that this pair of feed rollers (32a/34a), of which there is at least one, is arranged in the area of the feed path (16) over which the cutter (28) extends, and that the feed roller (32) disposed on the support table side of the feed roller pair (32a/34a), of which there is at least one, or of each further feed roller pair (32b/34b, 32c/34c) arranged in the area over which the cutter extends is overhung at the side and extends into a recess (40) in the support table (10).
2. Apparatus according to claim 1, in which the power generating means which apply the clamping power of the feed rollers (32a/34a) are working cylinders (36) to which pressure fluid is admitted, characterised in that the working cylinders (36) of the feed roller pair (32a/34a), of which there is at least one, are supported in a fixed manner and their cylinder chambers communicate with one another via an overflow line (38).
3. Apparatus according to claim 1 or 2, characterised in that the pair of feed rollers (32a/34a), of which there is at least one, is arranged in the third of the area over which the cutter extends which is on the run-in side.
4. Apparatus according to claim 1 or 2, characterised in that two or more feed roller pairs (32a/34a, 32b/34b, 32c/34c) are arranged in the area over which the cutter extends.
5. Apparatus according to claim 4, characterised in that, when there are a plurality of feed roller pairs (32a/34a, 32b/34b, 32c/34c), the axial extents of the lower feed rollers (32) decrease in length from the run-in area of the cutter (28) to the run-out area of the cutter (28), so that their ends lie approximately on a line parallel to the cutting edge (28).
6. Apparatus according to at least one of claims 1-5, in which the pressure device (18) consists of a series of pressure rollers (24), which can be pressed from above against the squared timber (14), characterised in that the respective upper rollers (34) of the feed roller pairs (32/34) are incorporated into the series of pressure rollers (24).
7. Apparatus according to claim 6, characterised in that the pressure rollers (26) and the upper rollers (34) of the feed roller pairs (32/34) are encircled by a common pressure belt (20), which is guided along the squared timber (14).

Images