DE3326843C2 - Band or frame saw machine - Google Patents

Abstract

The invention relates to a band or frame saw machine for sawing elongated wooden workpieces (13), the fibers (17) of which run in the direction of the wooden workpiece. The band or frame saw machine is preferably used when sawing tree trunks in their longitudinal direction. To increase the sawing speed, the angle between the fibers and an imaginary line perpendicular to the direction of movement of the strip or gate (15) is formed as an acute angle (δ), preferably of the order of 45 degrees. This can be achieved by inclining the belt or gate (15) inside the sawing machine or by inclining the feed slide on which the tree trunk is placed.

Description

In the embodiment according to the invention, the advance can be made relatively large, so that the Chips are much larger than those of the known sawing machines. You can see that the Chips in the inventive arrangement of the cutting angle are three to four times larger. Through this the formation of congestion is reduced

With the same performance as the known machines, the machines could be made lighter or with the same design can be driven with greater power in terms of their mass. Because of the discharge of the tooth tips by the configuration according to the invention, the service lives are longer; it will namely not scraped, but rather a tear-crack effect generated on the fibers. The set width can also be reduced, thereby reducing the Leadership is significantly improved. The gumming is reduced and for this reason too, the service life is increased of saws increased The decisive finding that supports the invention is that when making longitudinal cuts on wooden workpieces, the pressure angle of the saw blade or the individual tooth is as favorable as possible in relation to the longitudinal fibers of the wooden workpieces, if one normally starts from 90 ° and the angle between the perpendicular to the tape and the longitudinal wood fibers in steps of approx. 5 ° continuously changed against the feed, then one recognizes a considerable progressive acceleration of the Feed. The increasingly long chips also make it clear that the original The scraping effect turns into a gap-tearing effect, through which the acceleration of the feed is achieved. With In other words: the tooth tips protruding against the feed direction virtually grip between the individual ones Fibers, tear or split the individual chips in this way from the to be processed, i.e. H. to be sawed Wood off.

The dimensioning of the angle is according to the invention so that the line of flight over the tooth tips together with the average. The direction of the longitudinal fibers form an acute angle {ö 1), whereby one component of the angle in the sawing direction of the band is always opposite to the feed direction of the wooden workpiece. In any case, this angle must be less than 90 °. The angle according to the invention is in the graphic representation drr F i g. 1, 2 and 3 shown.

The invention is to be explained in more detail and made understandable on the basis of the respective drawing. It shows

F i g. 1 shows an illustration of the assignment according to the invention of the saw band (2) or saw frame to the average longitudinal fibers of the wood (t),

F i g. 2 shows the view of a standard wood part that is in a position according to the invention with a saw (1) + (2), with the resulting saw marks (D 2) and the point of application of the saw,

3 shows a schematic representation of the different, freely selectable angles δ 1 of the saw band, which according to the invention lie below 90 °: must (example in the graphic: bc d, e),

4 a graphical representation of the achievable Feed rates, based on the selected Angle. The flexibility within the angle scale is strongly recommended, so that the respective operational requirements Requirements can be met (product program).

In the drawings it is indicated that the acute angle ό 1 is the angle. which results between the alignment line over the sawtooth tips and the average wood fiber

The two different pointed angles that result from the side of the longitudinal fibers have a total of 90 ° (ό + άί).

In FIG. 1, the line NN means the perpendicular to the band extension, to the line of flight over the tooth tips or to the direction of movement (sawing direction) of the creel or band (including the blade edge).

The line Ni - N _t represents the direction of the fibers longitudinally in an elongated wooden workpiece to which the feed direction Pzm is used

Looking at FIG. 1 also understand how the incoming tooth tips penetrate better like a wedge between the individual wood fibers, can split and cut or tear off, so that not only sawn crosswise, but also split lengthways (relief of the tooth tips, or new distribution of forces). This gap-tear effect can reduce the service life of the saws.

According to the invention, the vacancy dl between the normal NN and the fibers 1 should now be an acute angle, ie between approximately 70 and 20 ° to enable optimal results.

The acute angles are measured from the vertical NN ai ^ ;, as shown in FIG. 1 z. B. down, against the feed direction. If you consider the angle δ 1 between the direction of the longitudinal fibers and the direction of movement of the saw, you can see that the angle δ 1 is equal to 90 ° minus the dent angle δ.

The cutting or saw marks (according to F i g. 2), which when sawing a piece of wood because of irregularities in the teeth almost always every single revolution z. B. a band saw, can be used very well to consider the sawing process. If the distance between two saw marks z. B. in the 90-degree section D \ , it becomes clear with a double-fast feed afterwards Di. B. with a 65-degree cut.

According to the invention, it is completely irrelevant whether the saw blade is from the band saw or the saw frame the vertical is inclined in an inclined position, or the feed carriage with the wood accordingly is inclined.

The F i g. Fig. 4 is a diagram showing d ^; e shows the dependence of the feed rate V, on the saw angle.

As a basis, 100% was assumed as the feed speed for softwood in a 90-degree cut.

The combination of the terms sawing and splitting However, this is only possible with materials such as naturally grown wood, with its contiguous Fibers, or other materials similar to the structure of wood, can be used successfully. Homogeneous T.laUritil, which has no grain direction, reacts very little or not at all to a change in the cutting direction or a saw angle in relation to the feed rates.

So it can also be made of compressed fiber boards such as fibreboard, chipboard. Blockboard, multilayer plywood or the like are advantageously cut in the angle according to the invention. The biggest success can of course be achieved when cutting natural wood in sawmills.

When looking at the sawdust you can see the following:

When the tooth tips penetrate between the individual fibers of the wood, they are split up and only then sheared off, with the chips corresponding

chend - V— get bigger and bigger. These lengthening chips can be clearly seen under the microscope and interesting images are created.

The more acute the cutting angle, the longer the sawdust. The initially mentioned scraping meal (wood dust) s will occur in smaller and smaller quantities, the larger the sawdust is "controlled".

If the tooth tips of the saws are not allowed to run in between the wood fibers at an acute angle δ 1, the success of the progressive feed rate according to the invention cannot be achieved.

If you z. B. cuts from the back of the wood fibers, the sawing process is slowed down.

According to the invention, a component of the cutting direction must never approach synchronism with the feed. Therefore, when constructing with swivel saws, care must be taken to ensure that all possible EinTiifswiiike! ^{over dis Zshniluchtünie the Ss 0} Cn must be below 90 °, so also the technically good transition angle of a gang saw machine.

In the embodiment according to the invention, according to FIG. 2 to see that the saw initially on a Attacks the edge of the tree trunk, then gradually grasps the entire trunk thickness. This becomes a relatively gentle, not sudden, insertion of the saw into the wood mass is achieved

This protects the machine and cuts the workpiece more precisely (the saw gradually comes in Guide).

For this purpose 2 sheets of drawings

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40

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Claims (2)

1 2 characterizing features of claim 1 solved claims: It has been found that when the fibers are exactly at right angles to the tape or the gate 1. Band or frame saw machine for sawing ter are advanced, comparatively small chips elongated wooden workpieces with fibers which are produced in FIG. 5, which, due to a scraping action, are to lead back in the direction of the longitudinal extension of the wooden workpiece. However, if the angle between the Kes run, for example, for sawing tree longitudinal fibers of the wooden workpiece to be sawed and the originate in their longitudinal direction, with a counter-ruchtline of the teeth of the saw band according to the invention is formed at an acute angle above the horizontal, the feed can be significantly increased in size with which the feed table to be sawed can be increased. Tests have shown that in one Wood workpiece in its longitudinal direction at the appropriate angular position according to the type of wood If the saw blade or gates are driven, machining is up to 100% faster (with softwood) In this case, saw bands with asymmetrical can be done, i.e. that the feed speed metric tips are used, which can be increased by up to 100% in the sawing direction, which is the case with hardwood d. H. in the direction of this saw band run bie band or 15 even up to 200% is possible Frame saws are inclined, thereby marked- In the known machines there is a limitation draws the fact that the wooden workpiece at the front of the feed speed thrust fed to the saw band or gate (2) ne further increase of the feed speeds is that the fibers (1) of the wood workpiece is with the for optimal efficiency of the known Ruchtlinie but the tooth tips of the saw teeth of the 20 sawing machines taking into account the peculiarity Saw building form an * acute angle (ίί) and άετ wood fibers not yet reached or explained one component of the sawing direction is always the front. The direction of thrust of the wooden workpiece is opposite. In the known devices, the the feed force for the wooden workpiece is not sufficient 2. Band or frame saw machine according to claim 25 to the effect, because of a certain scraping effect 1, characterized in that the angle (Jl) between the sawing inhibits. As a result, in the known sowing machines, the chips are comparatively small and only 20 ° by adjusting the angle according to the invention the chips become clear between the tape and the fiber 30 enlarged These relatively large chips have a higher dead weight, which means they are thrown out The invention relates to a baod or frame saw the tooth gaps are improved. Much of the har- maochine according to the preamble of claim 1. ze and the minerals remain in the larger chip portions Such sawing machines throw encapsulated in sawmills so that also the heart attack that the leaves used in which tree trunks are glued in the longitudinal direction 35 in the tooth area compared to the known sowing be sawed open. They have a frame for guidance that is somewhat less. It can be said that the resinification and to drive the belt or the gate and the saw blades is significantly reduced and also the a feed device, on which the wooden workpiece cut surfaces are flatter. Furthermore is still to be is supported and fed to the belt, or also lead that the known types of saws .; more dusty the machine is driven against the wood. 40 ge of chips that lead to dust explosions in the DE-PS 36 336 has disclosed a feed device for sawmills and other wood processing companies with full gates with roller feed, which can lead, in particular, in the chip bunker, in which the feed device on a rail track due to the significantly larger chip dimensions is applied, which are falling in the direction of advance, such dust explosions are considerably low, so that the trunk thereby has to fear a tendency to 45 rem circumference. automatic procedure and the work of the pre In a preferred manner, the angles lie between the Feed rollers are significantly relieved and, in addition, the grain direction and the saw band between approx. 70 ° and also the straight line of the trunk more reliable 20 °. will. The optimal angle depends on the type of wood From DE-PS 8 26 640 band saw tables be 50 or the wood hardness. It is therefore expedient to become familiar with the angles in which the table can be set via a specific angle setting between the saw band and the fiber inclination angle so that the direction of the wood can be gradually adjusted, made by particularly diverse angled cuts so that in particular in Steps of 5 ° can be the optimal one. Efficiency can be chosen. The DE-GM 19 24 1128 deals with a Gattersä- 55 The setting of the angle between the fiber and Ge with a compensator to remove the saw band can be achieved by either Feed inhibitions. In doing so, the ßand or the gate will stand vertically by means of a suitable Neten control of the angle of inclination of the saw blade of the feed carriage is inclined, or by the or gate based on the feed direction of the tape or the gate from the vertical into an inclined Trunk changed 60 position is brought, with the feed slide hori- In all of these devices, a zontal generally remains. Of course, there is also the possibility certain feed speed when cutting the tape or the gate and the feed slide achieved, however, tend for better efficiency of the; in any case, one of the Machine cannot be increased significantly. Ben angle between the tape or the gate and The object of the invention is to use a tape or gate 65 of the fiber direction (pointed win- sawing machine, in which the feed cone in the cutting direction of the saw band against the speeds can be increased significantly. Cutting feed, i.e. not at a sharp angle, According to the invention, this object is achieved by approaching the synchronism of the feed).