WO1988006935A1

WO1988006935A1 - Band saw

Info

Publication number: WO1988006935A1
Application number: PCT/DE1988/000141
Authority: WO
Inventors: Anton Koukal
Original assignee: Anton Koukal
Priority date: 1987-03-13
Filing date: 1988-03-14
Publication date: 1988-09-22
Also published as: EP0305457A1

Abstract

Band saw for sawing out work pieces along a closed contour, provided with a blade (14) moving on sawing band rollers (11, 12), of which one is disposed above the sawing table (13) and the other below the sawing table, said blade passing through an opening in the sawing table (13) in the working area. The band saw is also provided with a feed device (21) by means of which the sheet of raw material (29) is passed onto the sawing table (13), and with a control apparatus by means of which the relative movements of the sheet of raw material (29) and of the blade (14) are controlled according to the desired contour of the work piece to be sawn out. The blade (14) is prevented from deviating by guiding devices (32, 33) disposed above the working area and below the sawing table respectively, said guiding devices (32, 33) being together rotatable about an axis (34) with an angle sector of at least 360 DEG , running parallel to, and only a small distance from, the line (34) along which the points of the teeth of the blade (14) move during operation of the saw. The feed device (21) is in the form of a coordinate carriage, passing the sheet of raw material (29) in the direction of the mutually perpendicular X and Y coordinates.

Description

INTERNATIONAL APPLICATION PUBLISHED AFTER THE INTERNATIONAL COOPERATION AGREEMENT IN THE PATENT AREA (PCT)

(51) International patent classification ⁴ (11) International publication always: WO 88/06 B23D 55/08, 53/06 AI (43) Internationales

RELEASE DATE: September 22, 1988 (Sep 22

(21) International file number: PCT / DE88 / 00141 US. i (22) International filing date: March 14, 1988 (3/14/88)

Released

With international research report.

(31) Priority reference number: P 37 08 121.7 Before the expiry of the time limit for changes in claims P 38 00 475.5. Publication will be repeated if changes are received.

(32) Priority dates: March 13, 1987 (3/13/87) January 11, 1988 (1/11/88)

(33) Country of priority: DE

(71) (72) Applicant and inventor: KOUKAL, Anton [DE / DE]; Schumannweg 9, D-7325 Boll (DE).

(74) Lawyer: LUTZ, Johannes, Dieter; Hohentwielstrasse 41, D-7000 Stuttgart 1 (DE).

(81) Destination countries: AT (European patent), BE (European patent), CH (European patent), DE (European patent), FR (European patent), GB (European patent), IT (European patent), JP, LU (European patent), NL (European patent), SE (European patent),

(54) Title: BAND SAW

(54) Description: BANDSAW

(57) Abstract

Band saw for sawing out work pieces along a closed contour, provided with a blade (14) moving on sawing ba rollers (11, 12), of which one is disposed above the sawing table (13) and the other below the sawing table, said blade pas ing through an opening in the sawing table (13) in the working area. The band saw is also provided with a feed device (2 by means of which the sheet of raw material (29) is passed onto the sawing table (13), and with a control apparatus means of which the relative movements of the sheet of raw material (29) and of the blade (14) are controlled according to the desired contour of the work piece to be sawn out. The blade (14) is prevented from deviating by guiding devices (3 33) disposed above the working area and below the sawing table respectively, said guiding devices (32, 33) being togeth rotatable about an axis (34) with an angle sector of at least 360 °, running parallel to, and only a small distance from, t line (34) along which the points of the teeth of the blade (14) move during Operation of the saw. The feed device (21) is i the form of a coordinate carriage, passing the sheet of raw material (29) in the direction of the mutually perpendicular and Y coordinates. (57) Summary For a band saw for sawing out workpieces along a closed contour, with a saw blade (14) that runs over a saw band roller (11, 12) arranged above the saw table (13) and over a saw table and in the work area through an opening of the saw table (13), with a feed device (21), by means of which the raw material plate (29) can be moved on the saw table (13), and with a control device, by means of which the orientation of the relative movements of the raw material plate (29) and of the saw blade (14) can be controlled according to the desired contour of the workpiece to be cut out, the saw blade (14) above the working area and below the saw table is secured against evasion by means of a guide device (32, 33), the guide devices (32 , 33) together by a small distance from the line (34 ') along which the tips of the teeth of the saw blade s (14) move in saw mode and parallel to this line the axis (34) can be rotated within an angular range of at least 360 °. The feed device (21) is designed as a coordinate carriage, by means of which the raw material plate (29) can be moved in the X and Y coordinate directions running at right angles to one another

ONLY FOR INFORMATION

Code used to identify PCT contracting states on the headers of the international writings

Publish registrations according to the PCT.

AT Austria. FR France "; MR Mauritania

AU Australia GA Gabon MW Malawi

BB Barbados GB United Kingdom NL Netherlands

BE Belgium HU Hungary NO Norway

BG Bulgaria IT Italy RO Romania

BJ Benin P Japan SD Sudan

BR Brazil KP Democratic People's Republic of Korea SE Sweden

CF Central African Republic KR Republic of Korea SN Senegal

CG Congo Liechtenstein SU Soviet Union

CH Switzerland LK Sri Lanka TD Chad

CM Cameroon LU Luxembourg TG Togo

DE Germany, Federal Republic of MC Monaco US United States

DK Denmark MG Madagascar

IT Finland ML Mali

band saw

The invention relates to a band saw for sawing workpieces from raw material panels, for example wood, chipboard, plywood or blockboard or plastic panels, along a - usually - closed contour, with a self-contained, band-shaped saw blade, which has a above the saw table and runs over a saw band roller arranged underneath the saw table, and is driven by means of one of the same and is driven in the work area through an opening of the saw table, with a feed device by means of which the raw material plate can be moved relative to the saw blade and with a control device by means of which the orientation of the parallel relative movements of the raw material plate and the saw blade to the surface of the saw table can be controlled according to the desired contour of the workpiece to be cut out, the saw blade above the working area and below the saw table by means of a guide device each against an off soft in the direction of the feed movement on the one hand and against a lateral deviation from the plane required for the contour-correct course of the saw cut on the other hand, is secured. Band saws of this type are required for both manual and large-scale production, for example of furniture parts that are sawn from larger raw material panels, which have typical dimensions of 2 x 5 m and typical thicknesses of 12 to 20 mm. Often, several such raw materials are placed on top of one another in order to achieve workpieces with a correspondingly higher multiplicity by means of a sawing operation. Wood pieces with a maximum thickness corresponding to the height of such a stack can also be cut with such a band saw. While in this connection it is often necessary - in most cases flat - to achieve curved cutting contours with flat-plate-shaped workpieces, e.g. when sawing out door leaves or door leaf elements for doors that have a correspondingly curved door arch, it can be used to cut beam or board-shaped elements, usually of greater thickness, that are used as struts or frame parts become necessary to be able to make so-called miter cuts that run at 45 ° to the longitudinal direction of such an element. In order to be able to carry out such continuous changes in the orientation of a saw cut as well as step-by-step changes with subsequent straight-line continuation of the saw cut in this changed orientation, it is known to use numerically controlled (CNC-controlled) feed devices for the raw material feed, which perform a three-axis movement of the raw material enable such that it can be moved in two mutually perpendicular coordinate directions, the X direction and the Y direction, and, at least in a limited angular range, can be rotated about an axis perpendicular to the plane of the saw table. The one with such a feed directional design effort is considerable. The same applies mutatis mutandis to the electronic part of the control, since a contour-correct control of the raw material path movements required for a curved cut, which are achieved by superimposing two linear movements with one rotary movement, requires the use of complicated path computers, which are correspondingly expensive.

The object of the invention is therefore to provide a band saw of the type mentioned which, with a much simpler construction of the feed device, enables the sawing out of workpieces which have curved contour sections without loss of manufacturing accuracy and also with considerably less electronic-technical effort is controllable.

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

According to this, the guide devices, by means of which the orientation of the saw blade in the cutting area can be determined, are rotatably arranged together, so that the saw blade - while torsioning it - can be oriented as desired within an angular range of at least 90 °, that is, based on a condition with a torsion-free condition of the saw blade linked normal position of the same can be oriented by at least 45 ° clockwise and by at least 45 ° counterclockwise. In combination with this are then by means of an easy-to-implement coordinate carriage that the raw material can only be moved in two different coordinates which are perpendicular to one another must allow directions, workpieces with most of the contours that are relevant in practice can be sawed out. The realization of the rotatable arrangement of the guide devices, compared to known band saws, is associated with an additional technical outlay, but this is offset by a far greater saving in technical outlay with regard to the realization of the feed movement and control, so that the band saw according to the invention is constructed much simpler overall and is correspondingly cheaper to implement than a band saw of a known type with an appropriate design with regard to the variety of contour shapes that can be sawn out by means of the band saw. Due to the torsion that is impressed on the saw blade of the band saw according to the invention when sawing out a workpiece, the saw blade is not significantly stressed, since the band tensioning device that is usually present is designed in such a way that it keeps the saw blade tension constant.

This also applies if, in the preferred embodiment of the band saw according to the invention, the angular range within which the orientation of the saw blade can be changed with respect to its neutral position comprises a total of 360 °, in which case workpieces with all contours relevant in practice, in particular closed contours can also be sawn out of a raw material plate in one go. This is particularly advantageous since relatively small workpieces can now be sawn out of a large raw material plate without any problems, which can be done with a band saw of the known type, even if the raw material can be rotated through 360 ° around the polar Z axis, because of the size the plate - the more difficult the smaller the workpiece to be cut out is compared to the size of the raw material plate. With the band saw according to the invention, however, sawing out a small workpiece only requires feed movements of the raw material plate which correspond to the greatest dimensions of the workpiece measured in the coordinate directions. It is therefore, if relatively small workpieces are to be sawn out of a raw material plate, to be sawed beforehand into smaller sections which have a "machine-appropriate" shape, so that labor and time can be saved.

The features of claims 2 to 6, depending on the shape of the workpieces to be manufactured and / or the type of feed control used, indicate advantageous arrangements of the axis of rotation of the guide devices with respect to the saw blade, which ensure a contour-correct and low-waste sawing of the workpiece enable.

Due to the features of claim 7, a preferred design of the orientation of the saw blade in the cutting direction-imparting guide devices is specified, with inclined axes of lateral guide rollers, which ensures in a simple manner that the saw blade, even if it is twisted, also outdoors Run, ie even if it is not forced into the guide devices by the workpiece feed, cannot jump out of these. The features of claim 8 expediently specify values of the angle of inclination β to be observed, under which the axes of rotation of the lateral guide rollers of the guide devices can run inclined against the surface of the saw table.

Due to the features of claim 9, an alternative to cylindrical, inclined guide rollers is given alternative design of guide rollers of the guide devices, in which tapered rollers are provided, the axes of which can intersect in a horizontal plane at the cone angle. Due to their different peripheral speeds in the area of their smaller and larger diameters, such guide rollers also achieve a saw blade in contact with the support roller that rolls on the back of the saw blade.

A "jumping out" of the saw blade from the guide devices can also be prevented in a simple manner by the designs of the guide devices and the saw blade indicated by the features of claim 10.

It is achieved by the features of claim 11 that the guide devices - by adjusting the "slot width" between the lateral guide rollers - can be adapted to the thickness of the saw blade used in each case.

The features of claim 12 ensure that the guide devices can be adapted to different widths of saw blades that may be used. A feed device suitable for the path motion control of the workpiece or the raw material can, as indicated by the features of claim 13, be designed as a simple coordinate carriage, for the alternative by the features of claims 14 and 15 or 16, depending on the application, in particular Advantageous designs are specified, wherein the coordinate carriage in the design specified by the features of claims 14 and 15 is preferably suitable for sawing out several, relatively small workpieces from a larger raw material plate, while the alternative design specified by the features of claim 16 is a Coordinate carriage is preferably suitable for sawing out large workpieces in which cutting contours extend, for example, over almost the entire length of the respective raw material plate.

A CNC control provided according to claim 17 for controlling the feed movements and for controlling the orientation of the saw blade is compared with the CNC controls required for the known band saws

much less effort can be achieved, since the control input required for a certain orientation of the saw blade is always the same, regardless of the respective position of the raw material plate or the workpiece, and is always linked in the same way with a specific orientation of the workpiece contour and the direction of the feed movement.

Thanks to this advantageous property of the band saw according to the invention, its feed control and saw blade orientation control can also easily be carried out, as indicated by the features of claim 18, by means of a simple photoelectric tracking control device which operates on the principle of scanning a scale drawing template.

Orientation drives suitable for converting the orientation movements of a probe head provided in the context of a photoelectric scanning device into corresponding orientations of the guide devices of the saw blade can be implemented in a simple manner with the configurations indicated by the features of claims 19 and 20 - as rack and pinion drives.

In any case, it is advantageous if the orientation of the saw blade, as indicated by the features of claim 21, can also be carried out “by hand”. The band saw according to the invention can then also be used efficiently for sawing out “individual pieces”. The saw plan, according to which a workpiece or several workpieces are to be sawn out of a raw material plate, is expediently drawn up in such a way that a torsion of 180 °, for example clockwise, is impressed on the saw blade at the beginning of the sawing process, in which case the feed and Orientation control is taken so that the saw blade has a torsion of 180 ° counterclockwise at the end of the sawing of a closed contour. As a result, the overall torsional load on the saw blade can be kept to a minimum. Before a second workpiece with a closed contour is sawn out after sawing out a first workpiece, either the saw blade - by rotating the guide devices - is brought back into the appropriate initial torsion, or the saw plan for several workpieces is drawn up so that at the end of one Sawing process present torsion of the saw blade is just the "correct" initial torsion for sawing out the next workpiece, that is, the resulting change in the orientation of the saw blade again leads to a 180 ° end torsion thereof. If the angular range within which the saw blade can be twisted is increased to 450 ° in total, it is in principle always possible to make the saw plan for two workpieces to be cut out one after the other in such a way that they can be sawn out in a continuous sawing process without any torsion of the saw blade is exceeded by a maximum of 270 °.

Thanks to the simple design of the workpiece feed and the saw blade orientation control devices, these functional elements of the band saw according to the invention can also be implemented as additional devices to a conventional band saw. The invention also relates to a method for sawing out a workpiece using the band saw according to the invention, this method making it possible to operate the band saw as gently as possible without sacrificing the variety of possible designs of workpieces that can be sawed out with the band saw according to the invention.

This problem is solved according to the basic idea by the features of claim 22. The amount of torsion limitation provided hereafter, which can always be achieved by 360º compensation grinding of the relative movement of the workpiece and the saw band, minimizes the torsional load on the saw band.

The torsional changes required here can be carried out particularly quickly and easily if the workpiece, as indicated by the features of claim 23 and / or claim 24, is provided with recesses within which the 360 ° torsional changes in the saw band can take place without that a cut with narrow radii of curvature would be required for this.

Further details and features of the invention result from the following description of special exemplary embodiments of the band saw according to the invention and types of implementation of the method according to the invention with reference to the drawing. Show it :

1 shows a first embodiment of a band saw according to the invention with a photoelectric follow-up control device for controlling the feed of raw material and for controlling the orientation of the saw blade, in a simplified, schematic view from above,

2 shows a partial representation of the band saw according to FIG. 1, partly in section along the line II-II of FIG. 1,

3 shows one of the guide devices provided for orienting the saw blade in section along its plane of symmetry containing the axis of rotation,

4 shows the guide device according to FIG. 3 in a section plane running perpendicular to the axis of rotation,

5 shows a further embodiment of a band saw according to the invention, which is particularly suitable for sawing out elongated workpieces, in a plan view representation corresponding to FIG. 1,

6 shows a sawing plan for sawing out a workpiece using a first variant of a sawing method according to the invention, by means of which the saw blade is limited in torsion, Fig. 7 details of a further variant of the method according to the invention with raw material plate and prepared for its use

Fig. 8 details of a further design option in the frame of the band saw according to the invention usable guide devices in which the lateral guide rollers are designed as tapered rollers.

The band saw according to the invention shown in FIGS. 1 and 2, to the details of which is expressly referred to, designated overall by 10 corresponds to its basic structure according to a conventional carpenter saw with saw band rolls 11 and 12 arranged vertically one above the other, one of which is above one part of the band saw Machine table forming saw table 13 and the other is arranged below the saw table, wherein the self-contained saw blade 14 passes through an opening 16 or 17 of the saw table 13. One of these openings - the opening 16 - is arranged in that - central - region of the saw table 13 at which the workpiece 18 is sawn. In the exemplary embodiment shown, the other opening 17 is arranged on a laterally projecting part 19 of the saw table 13.

In the band saw 10, as usual, the lower saw band roller 12 is the driven roller, while the upper saw band roller 11 is carried along by the moving saw blade 14. The drive motor of the band saw 10 and the clamping devices for the saw blade 14 which are designed in the usual way are not shown for the sake of simplicity. These devices can be implemented in a known manner.

As can best be seen in FIG. 1, the band saw 10 is provided with a feed device, designated overall by 21, by means of which the workpiece 18 on the saw table 13 is perpendicular to one another Coordinate directions, the X direction represented by arrows 22 and 23 and the Y direction represented by arrows 24 and 26, can be moved in a controlled manner. In the special embodiment shown, this feed device 21 is designed as a so-called cross carriage, which has a longitudinal carriage 27 which can be moved back and forth in the X direction 22, 23 and one on the latter in the Y direction 24, 26. back and forth movable cross carriage 28 comprises, on which the raw material, such as a chipboard, a blockboard or a solid wooden plate 29 from which the workpiece 18 is to be sawn out, can be fixed.

This cross car 21 is, e.g. As is known in the art of milling machines or coordinate flame cutting machines, can be driven numerically or after-controlled in the X and Y directions 22, 23 and 24, 26 such that the movement of the workpiece 18 or the plate 29 results from the superimposition of these movements results, which corresponds to the contours 31 of the workpiece 18 provided.

In order to be able to achieve an orientation of the saw blade 14 in the work area corresponding to this contour course 31, the saw blade guide devices 32 and 33 arranged above the workpiece 18 or the plate 29 and below the saw table 13 or its central opening 16 are used in the FIG. 1 and in FIG. 2 are only indicated schematically, as is shown in more detail in FIGS. 3 and 4, to the details of which reference is now also made, arranged to be rotatable together about a vertical axis 34. These guide devices 32 and 33 are designed and constructed such that the orientation of the saw blade with respect to an initial orientation with which the sawing machining of the workpiece 18 is started can be changed by at least 360 °, thereby ensuring that a closed, for example rectangular, one , can also be sawn out, if necessary, characterized by a curved profile.

It is advantageous if the saw blade 13 at the start of a sawing process, e.g. seen with respect to the X-direction 22, 23, has an initial torsion of, for example, 180 °, which is initially "taken out" as it were when the closed contour 31 of the workpiece 18 is bypassed, in order to then "grow" in the opposite sense to 180 °, as a result of which the torsional load of the saw blade 14 can be kept to a minimum overall.

Before the structural details of the guide devices 32 and 33 are explained in more detail with reference to FIGS. 3 and 4, the basic principle of the feed control is first explained with reference to FIG. 1, which is carried out here according to the principle of photoelectric follow-up control which is known per se. For this purpose, a photoelectric probe head 37 is provided on the machine frame about a vertical axis 36 or an axis that runs perpendicular to the plane in which the workpiece can be moved, in a manner not shown in detail, "below" one of which is the target contour of the workpiece 18 reproducing drawing 38 is arranged, which also carries out the movements of the transverse carriage 28 or the workpiece 18. This probe 37 detects the orientation of the contour of the workpiece 18 ting drawing line 39 and generates two electrical output signals, one of which is proportional to the sine of the angle, which the drawing line includes with the X direction 22,23 and the other of which is proportional to the cosine of this angle. The feed of the transverse carriage 28 in the Y direction 24, 26 is controlled with the sine-proportional output signal of the probe 37, while the feed in the X direction 22, 23 is controlled with the cosine-proportional output signal of the probe 37, the feed speeds of the Workpiece 18 are proportional to the sine or cosine values in the directions mentioned. This results in a constant path tracking speed.

With this type of caster-controlled feed movement of the plate 29 or the workpiece 18, it is expedient, in order to achieve the most exact possible match of the workpiece contour 31 with the drawing contour 39, if, as shown in FIG which the guide devices 32 and 33 can rotate together, runs in the region of the teeth 40 of the saw blade 14, for example, as shown, approximately along the envelope of the "tooth roots", possibly also along the envelope 34 'of the tooth tips. It is understood that the axis of rotation 34 could also run more in the central region of the saw blade 14, in which case it must be taken into account in the drawing 38 by the course of the drawing contour 39 that the saw cut contour is defective in that the workpiece 18 turns out to be somewhat "smaller" than the drawing, with such narrowing of contours occurring where the contour is curved. Through such a deviation of the saw cut course from the design taking the drawing into account, however, a workpiece 18 can always be produced with the respectively required target contour.

The coordinate drive motors 41 and 42 of the transverse carriage 28 and the longitudinal carriage 27 are controlled by means of the sine (α) or cosine (α) proportional output signals of the probe 37.

These coordinate drive motors 41 and 42 of the transverse carriage 28 and the longitudinal carriage 27 could, of course, also be controlled by means of a numerical path control (CNC control), by means of which a drive device is also controlled, in order to “traverse” a predetermined desired contour of the workpiece 18. which controls the orientation of the guide devices 32 and 33 equally.

In the special exemplary embodiment according to FIGS. 1 to 4, rack and pinion drives are provided which mediate the form-fitting coupling of the orientation movements of the probe head 37 and the guide devices 32 and 33.

Before going into this in more detail, the structure of these guide devices 32 and 33 will first be explained with reference to FIGS. 3 and 4 using the example of the guide device 33 arranged below the saw table 13.

The guide device 33 comprises a basic cylindrical cylindrical block 43 which rotates in one Axis 34 coaxially surrounding bearing shell 44, which is fixedly connected to the machine frame in a manner not shown, rotatable about the axis 34 and immovably mounted in the axial direction. The block 43 is formed symmetrically with respect to its vertical longitudinal center plane 46, the orientation of which also determines the orientation of the saw blade 14. The block 43 has a central recess 47, which is rectangular in cross section in the illustration in FIG. 4, through which the saw blade 14 passes in the axial direction. From this recess 47 a narrow, outwardly open slot 49 emanates, the perpendicular width measured at right angles to the plane of symmetry 46 - the vertical longitudinal center plane of the block 43 corresponds to the distance of the teeth 51 of a gear 52 measured along the root circle 49, which is fixed to the Block 43, is attached to the underside of the guide device 33 and meshes with a rack 59 provided for the orientation drive of the guide device 33. This gear 52 and the bearing shells 44 are also provided with longitudinal slots of corresponding internal width, which can be brought into alignment with one another for the purpose of mounting the guide device 33. This is necessary so that the saw blade 14 can be brought into the arrangement shown in detail in FIGS. 3 and 4 with respect to the guide device 33.

On the block 43, a support roller 54 is rotatably mounted about an axis 53 extending at right angles to the longitudinal center plane 46, which rolls on the back 56 of the saw blade 14 according to the illustration in FIG. 3 in a clockwise direction when the latter moves in the direction of the arrow 57 downward executes. This support roller 54 - a corresponding roller is also present in conventional guiding devices - absorbs the forces exerted on the saw blade 14 which result from the feed movement of the workpiece 18 and act in the direction of the saw blade center plane.

Furthermore, two guide rollers 58 and 59 are rotatably mounted on the block 43, which support the saw blade 14 against lateral evasion. The axes of rotation 61 and 62 of these two guide rollers 58 and 59 run parallel to one another and are inclined with the course shown in FIG. 3 by an acute angle p against the horizontal direction marked in the illustration in FIG. 2 by the plane of the saw table top 13.

As a result of this inclination of the axes of rotation 61 and 62 of the guide rollers 58 and 59, when the saw blade 14 is twisted for orientation in the respective cutting direction, a force urging the saw blade against its support roller 54 against the support roller 54 results, that the saw blade 14 remains in contact with the support roller 54, even if it runs freely, that is to say is not forced through the workpiece into contact with the support roller 54.

A corresponding effect can also be achieved with the help of conical guide rollers, the axes of rotation of which lie in the horizontal plane, but enclose an acute angle corresponding to the cone angle, with such tapered rollers with its smaller diameter end should roll more near the teeth and with its larger diameter end near the back 56 of the saw blade 14, so that this repelling effect occurs.

The structure of the upper guide device 32 is completely analogous to that of the lower guide device 33, so that its separate description can be dispensed with.

The orientation of the guide devices 32 and 33 and that of the probe 37 takes place by means of a drive motor 63 which is fixed to the frame and has two drive pinions 64 and 66, one of which is provided for the orientation drive of the upper guide device 32 and the other of which is intended for the orientation drive of the lower guide device 33, the latter two pinions 64 and 66 are seated on a single shaft 67 which passes through the laterally projecting part 19 of the table top 13 and which passes through an opening 68 of the saw table top 13 provided for this purpose. The upper drive pinion 64 of the drive motor 63 meshes with a toothed rack 50 which extends in the X direction and which in turn meshes with an orientation drive toothing 68 of the probe head 37. Furthermore, the upper drive pinion 64 of the drive motor 63 meshes with a toothed rack 69 which runs at right angles to the rack 50, that is to say in the Y direction, and which in turn meshes with the orientation drive gear 52 'of the upper guide device 32.

The lower drive pinion 66 is in meshing engagement with a rack 71 which - below the sawing table 13 - runs parallel to the rack 69 of the upper orientation drive and in turn meshes with the orientation drive gear 52 of the lower guide device 33. The racks 69 and 71 are supported by frame-fixed slide guides 72 and 73 and frame-mounted support rollers 74 and 76 and 77, the practical arrangement of which can be seen in FIGS. 1 and 2, against disengagement from their meshing engagement with the orientation teeth of the probe head 37 and the guide devices 32 and 33 secured.

The band saw 10 according to FIGS. 1 and 2 is suitable for processing elongated, board-shaped plates 29, for the fixing of which to the transverse carriage 28 clamping elements 78 are provided, which engage on a longitudinal edge 79 of the plate 29 and this with its other longitudinal edge 81 against stops 82 of the cross car 28 push. In this case, the cross carriage 21 has the design of a "portal carriage", the longitudinal carriage of which can be guided on the longitudinal edges 83 and 84 of the saw table 13 which run in the X direction. The X drive of the longitudinal carriage 27 and the Y drive of the transverse carriage 28 are expediently designed as rack and pinion drives.

After sawing out a workpiece 18, the coordinate carriage 21 can be "reset" in the X direction by the corresponding extent of the workpiece and fixed again on the plate 29, so that the drawing template 38 is required only once per X length of the workpiece. In the design shown in FIG. 1, the band saw 10 according to the invention is inexpensively small in the X direction, in the Y direction the possible displacement path relative to the saw blade 14 must correspond to the width of the plate 29. In practice, this means that the width of the saw table 13 measured in the Y direction corresponds approximately to twice the width of the workable plates 29.

The band saw 10 according to FIG. 1 is indeed suitable for the production of a large number of relatively small workpieces 18 from a very long but relatively narrow plate 29, which essentially only has to be supported on a table surface for machining by means of the saw 10, which is little is larger than the workpiece area itself, plus the area occupied by the coordinate carriage 21. However, it is not suitable for precisely machining workpieces with a length of several meters.

For this second purpose, the embodiment of a band saw 10 'according to the invention shown in FIG. 5, to the details of which is now referred to, is suitable, which is constructed and operates according to the same basic principle as the band saw 10, but differs from it in that one of processing plate 29, with its entire long side 79 'is fixed to the coordinate carriage 21'.

Insofar as the functional elements shown in FIG. 5 are given the same reference numerals as in FIGS. 1 to 4, this should refer to their structural and functional analogy to these elements and, at the same time, also refer to the relevant parts of the description in order to avoid repetition.

The essential difference between the band saw 10 'according to FIG. 5 and the band saw 10 according to FIG. 1 is the larger area of the machine table 13, the width measured in the Y direction and the length measured in the X direction in each case at least twice the value in the same direction corresponds to the measured extension of the plate 29, plus the width of the transverse carriage 28 ', which here extends practically over the entire length of the machine table 13 and by means of two pinions 86 and 87, which mesh with racks 88 and 89, which run along the Directional transverse edges of the table top .13 are driven, which are arranged at the ends of an elongated shaft 91 which is rotatably mounted on the cross carriage 28 ', the drive motor 41. of the cross carriage 28'. together with the transverse carriage 28 '. is movable and one of the two pinions - the pinion 87 drives. On the cross carriage 28 '. is the longitudinal carriage 27 'which can be moved back and forth in the X direction. guided and by means of the drive motor 42, the drive pinion with a longitudinal toothing of the cross carriage 28 '. combs, drivable. The drive control of the coordinate carriage 21 '. can also, as already mentioned, be controlled numerically or according to the principle of run-on control. A drawing template suitable for follow-up control, which is shown by the contour 39 '. is represented, in this case is placed on a base plate 91, the X dimension of which corresponds to that of the plate 29.

In the band saw 10 ', the plate 29 is fastened to a longitudinal bar 92. Of the longitudinal carriage 27', for example with the aid of screws 93, which are distributed over the length of this bar 92 and each protrude only a few millimeters into the plate 29. This achieves a sufficiently secure fixation of the plate 29 'to the coordinate carriage 21', provided that the friction between the plate 29 and the saw table 13 'is sufficiently low, which e.g. can be achieved in that the plate "floats" on a compressed air cushion or is supported on this friction arm by ball rollers embedded in the table top 13.

Both the band saw 10 '. 1 and 2 as well as the band saw 10 'according to FIG. 5 can be designed such that processing of a stack comprising a plurality of plates 29' is possible if several identical workpieces are to be sawn out in one operation.

It goes without saying that instead of a tracking control by means of a photoelectric probe head or a CNC control, a "manual control" of the saw blade orientation is also possible, in which case the "division" of a predetermined feed rate into X and Y components by means of a sine / cosine

Potentiometer takes place that detects the "hand" given orientation of the guide devices .32 and 33 'and generates control signals proportional to these angular functions for the control of the coordinate drive motors 41 and 42.

The band saws 10 'and 10' according to FIGS. 1 and 5 are distinguished from band coordinate controlled band saws by a considerable simplification of the structure and type of control. They also convey the advantage that much larger raw material plates 29 can be processed within a space of a given size.

With reference to FIGS. 6 and 7, to the details of which reference is again expressly made, methods for sawing out a workpiece with any desired contour are explained below, these methods requiring the use of a band saw 10 or 10 ′ according to the invention.

The purpose of these procedures here is to avoid excessive torsion of the saw blade or to limit it to an amount which in any case ensures gentle operation of the saw.

The basic idea of the method is that whenever the torsion of the saw blade 14 reaches a relatively high value of, for example, 180 ° or more, the torsion of the saw band 14 is reduced again before due to the cut, a no longer tolerable value of the saw blade torsion is achieved.

The measures provided for such a reduction of the saw blade torsion according to the invention are the following:

1. Cut outside the workpiece 95 along a loop-shaped path 96 which, compared to the torsion that the saw blade 14 had when it "left" the workpiece contour 31, leads to a reduction in the torsion or even to a torsion in the opposite sense leads.

2. Attachment of slot-shaped recesses 97 to areas of the raw material plate 29 arranged outside the workpiece 95, the minimum amount of the clear widths of such recesses 97 being significantly greater than the width of the saw blade 14, so that it is within the respective recess 97 after it has entered the recess 97 along a stitch-cutting path 98 leading away from the target contour 29 of the workpiece, rotated in the opposite direction to "remove" a specific torsion within the latter, and can also be brought into a starting position from which it already exists started workpiece contour cutting can be continued with a smooth connection. For the workpiece 95, without restricting the generality, that is to say only for the purpose of explanation, assuming the shape shown in FIG. 6, with a total of twelve rectilinear sections 101 to 112 of its outer contour 31, the convexly curved outer corner sections 113 and concave curved inner corner sections 114 with smooth curvature, perpendicular to each other, connect in pairs.

For the purpose of the further explanation below, it is agreed that the torsion which the saw blade experiences when it is rotated clockwise about its longitudinal axis 34 'is counted positively and accordingly a torsion of the saw blade is counted negatively, the torsion in angular degrees is indicated with respect to that plane 116 which is distinguished by the torsion-free state of the saw blade 14, with which plane also those course planes of the saw blade 14 coincide if torsions are embossed thereon which correspond to positive or negative integer multiples of 180 °.

In FIGS. 6 and 7, the saw blade 14 is represented in each case by a short arrow surrounded by thin lines, the arrow tip of which represents the toothing 40 of the saw blade 14. The torsion-free condition of the saw blade corresponds to its orientation in the -X coordinate direction. The respective cutting direction is thus indicated by the orientation of this arrow representing the saw blade 14. The arrows 117 and 118, which are directed in the opposite direction to the orientations of the saw blade 14, indicate that Feed directions of a workpiece 95 in the -X coordinate direction or the + X coordinate direction and the direction of arrows 119 or 121 indicate the feed directions of the workpiece 95 in the + Y coordinate direction or the -Y coordinate direction.

In the exemplary embodiment of the sawing method illustrated by FIG. 6, the raw material plate 29, the. is only schematically indicated in broken representation, is oriented with respect to the saw blade 34 and is fixed to the coordinate carriage 21 or 21 'that the first straight section 101 of the workpiece contour runs in the plane 116, which corresponds to the torsion-free orientation of the saw blade 14 or a torsion the same of n. 180 ° (n = 0, ± 1 ...) corresponds.

Taking into account the contour course 31 of the workpiece 95, which in the course of sawing out the workpiece causes the saw blade 34 to be subjected to increasing clockwise torsion, ie a positively counted torsion, the saw blade 14 is subjected to torsion in the direction of the torsion. Arrow 122 issued an initial torsion of -180 °. During the sawing out of the workpiece 95 along the first rectilinear contour section 101, the coordinate carriage feed takes place in the -X direction 117. During the cutting out of the convexly curved corner section 113 adjoining the first rectilinear contour section 101, over which the second rectilinear contour section 102 ″ at right angles "adjoining the first contour section 101 is reduced the torsion of the saw blade 14 to -90 °. While the second rectilinear contour section 102 of the workpiece 95 is sawed out, this or the raw material plate 29 is displaced in the + Y coordinate direction 119. When the saw cut passes from the second rectilinear contour section 102 to the third rectilinear contour section 103, which, again in a clockwise direction, takes place along the lower convex corner section 113, which is shown on the right in FIG. 6, the torsion of the saw blade 14 is again reduced by 90 ° , ie the saw blade 14 is torsion-free, while the third rectilinear contour distance 103 is sawn out, the raw material plate 29 being displaced in the + X direction 118.

In the further course of the sawing process, the torsion of the saw blade 14 while the fourth rectilinear contour section 104 of the workpiece 95 is cut has the value + 90 °, and, while the fifth rectilinear section 105 of the workpiece contour is sawn, the value + 180 °, because connect these contour sections 104 and 105 respectively "clockwise" to the previously sawn-out contour section 103 and 104 via the convexly curved corner sections 113.

Since the sixth rectilinear contour section 106 and the seventh rectilinear contour section 107 of the same selected exemplary embodiment of the workpiece 95 also adjoin the contour section 105 and 106 to be sawn out beforehand, this would result for the saw blade 14 while the seventh rectilinear one Contour section 107 is cut, a torsion of + 360 °. Assuming that such a high torsion of the saw blade 14 is not expedient, after the transition from the saw cutting process from the fifth rectilinear contour section 105 to the sixth rectilinear contour section 106 - according to the invention - it lies in an "outside" of the workpiece 95 In the area of the raw material plate 29, a cut is provided, by means of which a change in the torsion of the saw blade 14 is achieved in such a way that it remains - in terms of amount - less than a threshold value, which with sufficient long-term stability of the band saw 10 or 10 ' , which is of course reduced by the torsional load on their saw blade 14, is still compatible.

It can be assumed that the torsional loads occurring in a band saw 10 or 10 ', as explained above, can be easily accepted when using the commercially available saw blades if the torsion of the saw blade is not appreciable in terms of a threshold value of 270 ° exceeds.

This threshold was determined on the basis of extensive tests using various saw blade brands.

In order to avoid that in the exemplary embodiment according to FIG. 6, the torsion of the saw blade 14 increases to an impermissibly high value of, in the exemplary embodiment shown, 360 ° during the transition from the sixth straight contour section 106 to the seventh straight contour section 107, it is provided that in the region of the raw material plate 29 not belonging to the workpiece 95 a 360 ° cut loop 96 is passed in a counterclockwise direction, which starts from the sixth straight contour section 106 and leads back to it, with a tangential connection at a previously cut point of the contour section 106.

In the illustrated, special explanatory example, the torsion of the saw blade 14 is changed to a torsion of -90 ° after it has reached a value of + 270 ° during the transition from the fifth straight contour section 105 to the sixth straight contour section 106 of the workpiece contour, so that when cutting out the seventh rectilinear contour section 107, which adjoins the sixth rectilinear contour section 106 in a clockwise direction, the torsion 0 ° for the saw blade 14, ie Freedom from torsion. The same result - freedom from torsion of the saw blade when cutting out the seventh rectilinear contour section - could also have been achieved by running a 360 "cut loop 96 'indicated by dashed lines in FIG. 6 and starting from the fifth contour section 105 in a counterclockwise direction.

In the further course of the cut, the torsion of the saw blade 14 assumes the value -180 ° as soon as the ninth straight contour section 109 is reached. Since there are two more rectilinear contour sections 110 and 111, each adjoining each other at right angles, with the cutting out of which an increase in the saw blade torsion to 360 ° would be associated before the torsion would decrease again, one more Torsion change can be made, which is achieved in the illustrated, special explanatory example by a further cutting loop, which is designated 124 as a whole, starting from the ninth rectilinear contour section 109 and leading back to it. A total change in the torsion of the saw blade 124 by 360 ° is also achieved by passing through this cutting loop 124. The torsion of the saw blade is changed from -180 ° to + 180 °.

The cutting loop 124 imparting a change in the torsion of the saw blade 14 in the positive sense of change comprises a 90 ° deflection section 126 leading away from the cutting contour 109, on which the torsion of the saw blade 14 "increases" again in the negative sense of change. This section 126 is followed by a first, "positive" 270 ° change loop 127, which connects to a second + 270 ° change loop 129 via a cutting path 128 running parallel to the rectilinear contour section 109 of the workpiece 95, which in turn connects via a 90 ° arcuate connection cut 131 smoothly adjoins the continuation part of the ninth straight contour section 109, the saw blade 14 having a positive torsion of + 180 ° being impressed after passing through the further cutting loop 124. After this, the workpiece 95 can be completely cut out with the specified contour profile without further cutting grinding having to be provided to limit the torsional amount of the saw blade. A torsion adjustment of the saw blade 14 to the shape of the contour 31 of the workpiece 95, which enables the contour cut to be carried out overall in a continuous sawing operation, in such a way that the torsion of the saw blade becomes a maximum of approximately 270 ° in a further embodiment of the saw according to the invention. The method can be achieved in that the raw material plate 29 is provided in an area in which one or more cut grinding would otherwise have to be carried out with a slot-shaped recess 97, the longitudinal center plane of which runs parallel or approximately parallel to the straight contour section 109. The clear width w of the recess 97 measured at right angles to the rectilinear contour section 109 or to the longitudinal center plane 132 is somewhat, for example 20% larger than the width b of the same measured between the back 56 of the saw blade 14 and the envelope 34 'of its teeth 40.

The lateral distance of the longitudinal edge 133 of the slot-shaped recess 97 adjacent to the rectilinear contour section 109 from said contour section 109 corresponds at least to the radius of curvature r of the Stiσh cut 98, along which the saw blade 14 away from the rectilinear contour section 109 - changing its torsion by -90 ° - can be inserted into the recess 97.

The extent 1 of its longitudinal edges 133 and 134, which is parallel to the longitudinal center plane 132 of the elongated hole recess, of its longitudinal edges 133 and 134, which is parallel to the longitudinal center plane 132, is at least equal to the sum of the radii r of the stitch Cutting piece 98 and a connecting cutting piece 136, along which the saw blade 14 - out of the recess 37 - can be brought back with a smooth connection to the cutting contour 109 of the workpiece 95, plus the width b of the saw blade 14, the radii of curvature of the Section 98 and the connecting section 136 have the same value r.

The extent of the elongated hole recess 97 measured along the longitudinal center plane 132 is overall greater by the clear width w of the same than the extent 1 of its rectilinear longitudinal edges 133 and 134, with half the value of the clear width w the radius of curvature of the "transverse edges" 137 and 138 corresponds to the elongated hole recess 97.

With this configuration of the recess 97, the saw blade 14 can be "pushed back" while the raw material plate is in the + X direction 11 by the length 1 compared to the direction of movement with which the workpiece 29 is moved in order to saw out the straight contour section 109. will be twisted by +540, whereby the torsion of the saw blade within the clear space of the elongated hole recess and the setting back of the raw material plate in the + X direction 118, compared to the exemplary embodiment explained with reference to FIG. 6, can take place much faster than that Execution of the cutting loops 36 or 124, in which relatively long cutting contours have to be traversed with the - necessarily limited - cutting speed. In addition, after passing through the connection cut 136, the waste piece 139 can detach itself much more easily from the plate material than the waste pieces 141 or 142, 143, and 144 formed during the cutting loops 96 and 124 according to FIG. 6, since this is the case in the exemplary embodiment resulting waste piece 139 can easily escape into the recess 97.

Both the execution of the loop cuts 96 and 124 according to FIG. 6 as well as the stitch-cut path 98 leading into an elongated hole recess 97 and the connecting-cut path 136 leading out of the recess 97 as well as the relative movement which the workpiece 29 has with respect to the Saw blade 14 experiences while it is located within the slot 97, caster can be controlled, ie by tracing a drawing line by means of the probe head 37 of a tracking control device of the type described with reference to FIG. 1, but in the case of the exemplary embodiment according to FIG. 7, the drawing template must contain markings, when "recognized" by the probe head 37, a control command for twisting the torsion Saw blade is triggered by the required amount.

In this regard, suitable possibilities of numerical control or follow-up control are known per se, so that their appropriate use in the procedures explained with reference to FIGS. 6 and 7 is possible for the person skilled in the art at any time and therefore a detailed description does not appear to be necessary. In the case of the exemplary embodiment according to FIG. 7, however, if the path movement is controlled by tracking, ie by scanning a drawing template 38, it must be ensured that the detection of the stitch cut contour of the drawing by the probe does not lead to a "repetition" of the movement path intended for the torsion change leads, but this can be avoided, for example, by triggering a signal when the torsion drive is switched on or off, which, generally speaking, prevents repetition of the stitch-cut movement.

With the procedures explained with reference to FIGS. 6 and 7, the appropriate adaptation of which to a planned workpiece contour is readily possible for a person skilled in the art, workpieces of any shape can be sawn out of raw material plates 29 efficiently and precisely in a simple manner.

It goes without saying that the method according to the invention can also be used for sawing out a workpiece 95 with "sharp-edged" corner regions. For example, instead of the convexly curved outer corner section 113 of FIG. 6, a "sharp-edged" outer corner 113 'can be achieved if, instead of the 360 ° loop 96', only a 270 ° loop 96 '' is carried out, as indicated by dash-dotted lines.

Furthermore, it goes without saying that in an analogous, control-technically only slightly more complex modification of the method according to the invention, sharp-edged inner corners can also be achieved if in their immediate vicinity a recess analogous to the recess 134 according to FIG. 7 is provided, in which the cutting direction of the saw blade " can be reversed ", in which case the cuts are each made into the inner corner 114 ', as is also indicated by dashed lines in FIG. 7.

A practical design of an inner corner section 114 'can also, as also shown in FIG. 7, for the inner corner, to which the straight contour sections 109 and 110 of the workpiece adjoin one another, consist in the fact that the workpiece has already been provided with a bore 141 here in preparation. whose diameter is greater than the width of the saw blade 14 and whose arrangement is such that the straight lines representing the contour sections 109 and 110 intersect within this bore 141 - in the "corner 114 '-.

Finally, some design variants of the band saw 10, in particular its guide devices 32 and 33, are discussed, some of which are alternative to those already available with reference to the designs explained in FIGS. 3 and 4, partly in combination with them.

Instead of circular-disk-shaped or cylindrical-ring-shaped guide rollers 58 and 59, as can be seen in FIGS. 3 and 4, it is also possible, as shown schematically in FIG. 8, to use frustoconical guide rollers 58 'and 59' ', the axes of rotation 61' and 62 of which 'then expediently lie in a horizontal plane running at right angles to the vertical longitudinal center plane of the saw blade 14 and intersect, approximately in the region of the toothing of the saw blade, the ends of the tapered rollers 58' and 59 'having smaller diameters being at the other of the teeth 40 of the saw blade 14 are arranged on the side 14. Tapered rollers 58 'and 59' of this type also impart the effect of keeping the saw blade 14 in contact with the support roller 54 which rolls on its back 56.

This support roller 54 is, regardless of the design of the guide rollers 58 and 59 or 58 'and 59' expediently arranged adjustable so that, in the event that the band saw is used with saw blades of different widths, each in precise contact with the band back 56th can be brought. In addition to the horizontal displaceability of the support roller 54, which is at least necessary for this purpose, it can also be expedient if it can also be distributed vertically, ie in the longitudinal direction of the strip. The adjustment and locking means required in this regard, which can be implemented according to common design principles, are not shown for the sake of simplicity. Likewise, the lateral distance between the axes of rotation 61 and 62 of the guide rollers 58 and 59 or the inclined axes of rotation 61 'and 62' of the tapered rollers 58 'and 59' should be adjustable in order to exactly match the gap between the respective guide rollers to the thickness of the Saw blade 14 to be able to adjust.

It can also be advantageous if, in particular, the guide rollers 58 and 59, the rolling area of which are significantly "narrower" than the saw blade 14, can be adjusted such that these rolling areas can be placed against the cheapest, strip-shaped areas of the saw blade 14, preferably in the middle between the band back 56 and the toothing 40 of the saw blade 14. For the sake of simplicity, the adjustment devices that are suitable for this purpose and that can be implemented according to common construction principles are not specifically shown.

Claims

1. Band saw for sawing out workpieces from raw material panels, eg wood, chipboard, plywood or blockboard or from plastic panels, along a closed contour corresponding to the shape of the workpiece, with a self-contained, band-shaped saw blade, which over one above the saw table, on which the raw material plate executes its working feed movements, and runs over a saw band roller arranged below this saw table and is driven by means of one of them and is driven in the working area through an opening of the saw table, with a feed device, by means of which the raw material plate is relative to the Saw blade can be moved on the saw table with a predeterminable feed rate, and with a control device, by means of which the orientation of the relative movements of the raw material plate and the saw blade running in the saw cut plane can be controlled according to the desired contour of the workpiece to be cut out, where in the case of the saw blade above the work area and below the saw table by means of a guide device in each case against deflection in the direction of the feed movement, on the one hand, and against lateral deviation from the arrangement of the saw cut required for the contour-conforming course of the saw cut Saw blade, on the other hand, is secured, characterized in that the guide devices (32 and 33) together by a small, at most approximately half the width of the saw blade (14) corresponding distance from the line (34 ') along which the tips of the teeth of the saw blade (14) during saw operation and the axis (34) running parallel to this line (34 ') within an angular range of at least 90 °, that is to say with respect to a neutral position of the saw blade (14) linked to a torsion-free state of the same by at least 45 ° can be rotated clockwise and at least 45 ° counterclockwise, and that the feed device (21) is designed as a coordinate carriage, by means of which the raw material plate (29) in two different, preferably perpendicular, X and Y coordinate directions (22 , 23 and 24, 26) can be moved in such a way that the relative movement of the raw material plate (29) to the section ante of the saw blade (14) resulting outer contour (31) of the workpiece (18), apart from tolerable deviations, corresponds to the target contour of the workpiece (18).

2. Band saw according to claim 1, d a d u r c h g e k e n n z e i c h n e t that the angular range within which the orientation of the saw blade (14) can be changed with respect to its neutral position comprises a total of at least 360 °.

Band saw according to claim 1 or claim 2, characterized in that the axis of rotation (34) about which the guide devices (32 and 33) can be rotated together is within the bandwidth of the saw blade between the envelope (34 ') of the cream (40) and the longitudinal median plane of the saw blade (14).

Band saw according to claim 3, characterized in that the axis (34) about which the guide devices (32 and 33) can be rotated together is within a tolerance range of ± 1 mm with the envelope (34 ') of the tooth tips of the teeth (40) of the saw blade (14) coincides.

Band saw according to Claim 1 or Claim 2, characterized in that the axis (34) about which the guide devices (32 and 33) can be rotated lies in the central plane of the saw blade (14) which is perpendicular to the axes of rotation of the saw band rollers (11 and 12) the teeth (40) and the back (56) of the saw blade (14).

6. Band saw according to claim 3, so that the axis (34), about which the guide devices (32 and 33) can be rotated, lies in the central plane of the saw blade (14), which is perpendicular to the axes of rotation of the saw band rollers (11 and 12).

7. Band saw according to one of the preceding claims, characterized in that the guide devices (32 and 33) each have a support roller (54) which is rotatable about a perpendicular to the direction of movement of the saw blade (14) axis (53) and on the back ( 56) of the saw blade (14) and two guide rollers (58 and 59) arranged laterally from the saw blade (14), which roll on the lateral longitudinal surfaces of the saw blade (14), the axes of rotation (62) of these lateral guide rollers ( 58 and 59), with a parallel course, are inclined at an acute angle to the plane of the saw table (13).

8. Band saw according to claim 7, characterized in that the inclination angle rD which includes the axes of rotation (61 and 62) of the two lateral guide rollers (58 and 59) marked plane with the plane of the saw table (13), between 5 ° and 30 ° , preferably between 5 ° and 15 °.

Band saw according to one of the preceding claims 1 to 6, characterized in that the guide devices (32 'and 33') each have a support roller (54) which rolls on the back (56) of the saw blade (14) and two laterally from Saw blade (14) comprises arranged guide rollers which roll on the lateral longitudinal surfaces of the saw blade (14), these lateral guide rollers being designed as tapered rollers (58 'and 59'), the axes of rotation of which are at a right angle to the - vertical - longitudinal center plane of the saw blade running - horizontal - plane and intersect at the taper angle (β '), the smaller diameter ends of the tapered rollers (58' and 59 ') being arranged on the side facing the toothing of the saw blade (14).

10. Band saw according to one of the preceding claims 1 to 6, wherein the guide devices each have a support roller, which rolls on the back of the saw blade, characterized in that the axes of rotation of lateral guide rollers of the guide devices (32 and 33) parallel to the plane of the saw table ( 13), and that the saw blade (14) is provided on at least one of its two longitudinal surfaces with a groove with which an annular rib of the guide roller rolling on this longitudinal surface of the saw blade (14) is in engagement.

11. Band saw according to one of the preceding claims 7 to 10, that the horizontal spacing of the guide rollers (58 and 59; 58 'and 59') is adjustable.

12. A band saw according to one of the preceding claims 7 to 11, so that the support roller (54) that can be rolled off on the back (56) of the saw blade (14) is adjustable, i. E. is at least horizontally displaceable and lockable in the position of its bearing suitable for passing on.

13. Band saw according to one of the preceding claims, characterized in that the feed device is designed as a cross carriage (21), one on the lateral longitudinal edges (83 and 84) of the saw table (13) in the X direction (22, 23) back and forth comprises a longitudinal carriage (27) which can be moved and driven, and a transverse carriage (28) which is guided and drivable back and forth in the Y direction (24, 26) thereof, the transverse carriage (28) on one of the saw table (13 ) arranged at a clear distance crossing bridge of the longitudinal carriage (27) and thereby in turn is kept at a clear distance from the top of the saw table (13) which is greater than the greatest thickness of a raw material plate or a stack of raw material plates (29) with the saw (10) can be machined and that the cross carriage (28) with on the lateral edges of the raw material plates (29) to be machined attachable holding devices, in particular clamping devices (78) is provided, by means of which the raw material plates (29) can be detachably fixed to the cross carriage (28). (Fig.1).

14. Band saw according to one of the preceding claims, characterized in that the feed device is designed as a coordinate carriage (21), with one on a longitudinal carriage (27) which is parallel to the longitudinal edges (83 and 84) of the saw table (13) in the X direction (22, 23) can be moved back and forth, and can be driven in the Y direction (24, 26) and can be moved and driven cross carriage (28) on which the raw material plates (29) to be processed can be fixed and thereby carry out the movements of the cross carriage (28).

15. Band saw according to claim 13, characterized in that the cross carriage (28) on a the saw table (13) at a short distance crossing bridge part of the longitudinal carriage (27) is arranged and thereby in turn is held at a clear distance from the top of the saw table (13) , which is greater than the greatest thickness of a raw material plate (29) or a stack of raw material plates that can be processed simultaneously with the band saw (10), and that the cross carriage (28) with on the lateral edges of the raw material plates to be processed (29 ) attachable holding devices, especially clamps devices (78) is provided, by means of which the raw material plates (29) can be detachably fixed to the cross carriage (FIG. 1).

16. Band saw according to one of the preceding claims 1 to 8, characterized in that the feed device is designed as a cross carriage (21 ') which comprises a longitudinal carriage (27') and a transverse carriage (28 '), the transverse carriage, that this longitudinal carriage ( 27 ') has a stop bar running in the X direction, on which a raw material plate (29) can be fixed with its long side, and that the width of the saw table measured in the Y direction and its length measured in the X direction are at least twice the width and length correspond to the workpiece to be machined (Fig. 5).

17. Band saw according to one of the preceding claims 13 to 16, characterized in that a numerically controlled feed drive unit (CNC control unit) is provided to control the feed movements and the course of the cutting contour, the feed speeds of the raw material plate (29) in X and Y direction controls such that the speed of the web movement of the raw material plate (29) or the workpiece (18), which results from the superimposition of the X and Y movements of the longitudinal and transverse carriages result, is constant and, depending on the location of the engagement between the plate material and the saw blade (14), via a drive device with which the guide devices (32 and 33) are rotatable, in Cutting direction or contour direction.

13. Band saw according to one of the preceding claims 13 to 16, characterized in that a photoelectric wake-up control device (37, 64, 41, 42) is provided for controlling the path movement of the raw material plate (29) or the workpiece (18), which the Orientation of the contour (39) of a drawing template (38) and the path movement of the raw material plate (29) or the workpiece

(18) controls such that the feed movements, which result from the superimposition of X and Y movements, result overall in a constant feed speed of the raw material plate (29) along a path corresponding to the contour (39) of the drawing template (38).

19. Band saw according to claim 18, characterized in that from the tracking of the drawing contour (39) resulting rotary movements of a probe (37) of the photoelectric-tracking control device by means of a rack and pinion drive device in the same direction rotary movements of the guide devices (32 and 33) are implemented.

20. Band saw according to claim 19, d a d u r c h g e k e n n z e i c h n e t that the rack and pinion drive means comprises a rack (67) with an orientation toothing (68) of the probe (37) on the one hand and on the other hand with a drive pinion. (64) of a drive motor (63), whose rotary movements can be controlled by output signals of a sine / cosine potentiometer, which are characteristic of the orientation of the probe (37), and that one with the drive pinion (64) of the drive motor (63) on the one hand and on the other hand with a rack (69) meshing with an orientation gear (52 ') of the upper guide device (32) and on the one hand with another drive pinion (67) of the drive motor (63) and on the other hand with an orientation gear (52) of the lower guide device (33) Intermeshing rack (71) are provided, the diameters of the orientation toothing (68) of the probe (37) and the orientation gears (52 'and 52) of the guide devices (32 and 33) having the same value.

21. Band saw according to one of the preceding claims 1 to 16, characterized in that the orientation of the guide devices (32 and 33) can be changed continuously by means of a setting device which can be operated by the user, while the feed control device is the raw material plate - preferably at a constant feed rate - moved along a path corresponding to the shape of the workpiece (18).

22. A method for sawing a workpiece from a raw material plate using a band saw according to one of the preceding claims 1 to 21, characterized in that the amount of torsion of the saw band (14) is limited to a value which is less than 360 ° , but is at least 270 ° and that the path of the relative movements of the workpiece (95) and the saw band (14) comprises torsion compensation loops, the passage of which causes a change in torsion of the saw band (14) by 360 °.

23. The method according to claim 22, characterized in that the 360º change in the torsion of the saw band (14) within a recess (97) of the raw material plate (29).

24. The method according to claim 23, characterized in that the recess (97) is designed as an elongated hole, the parallel longitudinal edges of which run parallel to a contour section of the workpiece (29), the length of these longitudinal edges (133 and 134) of the recess measured in the cutting direction (97) and the clear width of the outer dimension measured at right angles to it correspond at least to the width of the saw blade (14).