EP2335892B1 - Riving knife device for a saw unit - Google Patents

Description

The invention relates to a riving knife device for a saw unit according to the preamble of claim 1.

Such a device is from the US 1 602 040 A known.

The splitting wedge device is used for sawing beams / planks into several fins. These workpieces are usually sawed by means of two sawing units, which have vertical sawing spindles with a corresponding number of saw blades. They are used to saw the usually pre-planed workpieces in horizontal planes. In the transport direction of the workpieces behind the corresponding sawing units, the riving knife devices are arranged, whose splitting wedges engage in the saw grooves and prevent the sawing gap from becoming too narrow and the respective sawing unit jamming and cutting.

In addition, even after the sawing spindles on the slats resting feed rollers for transporting the workpieces can be used by the machine without the saw blades are clamped by the load from above.

The splitting wedges are separated by the intermediate strips, which are located approximately at the height of the sawn from the workpiece slats. Depending on the thickness of the slat, the thickness of the saw blade and, if necessary, the saw blade run, thin fitting plates must be used to bring the splitting wedges up to the height of the sawing gap. The riving knife devices are permanently installed and can therefore be difficult and time-consuming to adjust. The splitting wedges have a relatively large distance from the sawing units, thus resulting in the sawing splitter and / or workpiece splitter in the area be removed between the sawing units and the splitting wedges. This is often not reliable, so it often comes to stagnation. Since the splitting wedges are relatively long, they generate high friction in the sawing gap, whereby the feed rate for the workpieces is limited.

In addition, split rollers are known which are used at higher feed rates of the workpieces. The splitting rollers can roll in the saw grooves. However, due to their design, the splitting rollers have an even greater distance from the sawing gap and are even more complicated to set and adapt to the respective machining task and machining situation. The splitting rollers sit on a swivel arm, which is spring-loaded in the direction of the workpieces and presses the splitting rollers into the saw blade with spring force. Clamp the split rollers in the kerf or occur in the saw blade splitter, workpiece splinters, branches or the like, the split rollers are pressed against the spring force from the saw blade. This pivoting movement is monitored by a limit switch, which generates a signal, for example, to switch off the feed for the workpieces. This avoids machine damage, but every time there is a machine downtime that the operator has to eliminate. This reduces the productivity of the machine.

The invention has for its object to form the generic splitting wedge device so that it works reliably at high feed rates of the workpieces to be sawn. The set-up and adjustment effort should be reduced to a minimum.

This object is achieved with the features of claim 1.

In the splitting wedge device according to the invention, the riving knife carrier carrying the splitting wedges is resiliently yielding in the housing by means of the drive Load position charged. Due to this resilient compliance, the splitting wedges can be pushed out of the respective sawing gap in the event of disturbances, so that damage to the splitting wedge device and / or the machine is avoided. The splitting wedges have only a very short length, so that the friction they generate in the kerf is correspondingly low. As a result, the workpieces to be sawn can be transported at high feed speeds. The saw unit or the machine containing this saw unit can thereby work with high power.

Due to the use of a solid riving knife carrier on which the riving knives and intermediate strips can be fixed in a precise position, the riving knives and intermediate strips can be changed very easily and quickly, adjusted and corrected if necessary. By means of this riving knife carrier, the splitting wedges can be placed very close to the tool, so that releasing branches do not even fall out of the riving knives and can cause stagnation. It has also been shown that due to the very close setting much less splinters and splinters detach, which can lead to disturbances.

Further features of the invention will become apparent from the other claims, the description and the drawings.

Fig. 1

in Draufsicht eine erfindungsgemäße Spaltkeilvorrichtung in einer Holzbearbeitungsmaschine, die zwei Sägeeinheiten aufweist,

Fig. 2

in perspektivischer und vergrößerter Darstellung die erfindungsgemäße Spaltkeilvorrichtung.

The invention will be explained in more detail with reference to an embodiment shown in the drawings. Show it

Fig. 1

in plan view, a splitting wedge device according to the invention in a woodworking machine, which has two sawing units,

Fig. 2

in a perspective and enlarged view of the inventive splitting wedge device.

The splitting wedge device is used when sawing workpieces 1 in the form of beams / planks in several slats. In general, two sawing spindles are used, of which in Fig. 1 a saw spindle 2 can be seen. Both saw spindles are vertical and carry one of the auszusägenden slats corresponding number of saw blades 3, 4, which saw the usually pre-planed workpieces 1 in horizontal planes. The saws are in the feed direction 5 of the workpiece 1 right and left long side engaged. The saw blades 3, 4 advantageously saw the workpiece 1 over a little more than half the width of the workpiece 1. The sawing spindles 2 are located in the feed direction 5 of the workpiece 1 with a small distance one behind the other. In the illustrated embodiment, first, the saw blades 4 of the right saw spindle with the workpiece 1 into engagement. At a short distance behind the blades 3 of the left saw spindle 2 engage in the workpiece 1.

In the feed direction 5 with a small distance behind the saws (in the embodiment behind the left saw) a riving knife device 6 is provided which is provided with splitting wedges 7, which engage in the Sägenut and prevent the kerf is too narrow and clamps the left saw or the workpiece 1 cuts.

The splitting wedge device 6 is designed so that at high feed rates of the workpiece 1, the susceptibility reduced and the set-up and adjustment effort is limited to a minimum, even with different blade diameters and / or workpiece widths. The splitting wedge device 6 detects any faults and outputs corresponding control signals, which can be exploited, for example, to stop the advance of the workpiece 1.

The riving knife device 6 has a carrier 8, which may be mounted on the machine stand or on a spindle slide. The carrier 8 serves as a base plate for a guide element 9, which is advantageously formed plate-shaped. The carrier 8 has in the feed direction 5 of the workpiece. 1 extending elongated holes 10, which allow an adjustment of the carrier 8 and thus the entire splitting wedge device 6 transversely to the saw spindle 2 and parallel to the feed direction 5. Through the slots 10 protrude (not shown) screws with which the carrier 8 is mounted on the machine stand or the spindle slide. On the support 8, a holding plate 11 is provided for a pressure cylinder 12, with which a riving knife carrier 13 in the direction of the workpiece 1 can be loaded. The holding plate 11 is transverse, preferably perpendicular, from a support plate 14 which is fixed to the underside of the carrier 8 and projects beyond the riving knife carrier 13 opposite edge of the carrier 8. The support plate 14 may also lie at the level of the support 8 and be formed integrally with it. On the support plate 14, an angular support piece 15 is arranged, the vertical leg 16 serves as a holder for a sensor 17, which is advantageously an inductive proximity switch. The horizontal leg 18 of the support piece 15 has at least one, in the embodiment two slots 19 through which screws 20 extend, with which the support piece 15 can be mounted on the support plate 14 and their heads, preferably with the interposition of at least one washer 21 on the Legs 18 rest. With the support piece 15, the proximity sensor 17 can be accurately positioned.

As Fig. 1 shows, the proximity sensor 17 passes through the vertical leg 16 of the supporting piece 15 and is screwed into this in a threaded bore 70. It cooperates with a holder 22 whose longitudinal center plane is parallel to the axis of the proximity sensor 17. By mounting in the threaded hole 70, the switching distance of the sensor 17 to the end face 69 of the holder 22 can be set exactly. On the holder 22, a piston rod 23 is fixed, which protrudes from the pressure cylinder 12 and the holding plate 11 passes through the game. At the side facing away from the holding plate 11 side of the holder 22 is attached to a slider 24, in the embodiment with the screws 71, 72 (FIG. Fig. 1 ) screwed. Slider 24 and holder 22 may also be integrally formed, for example, welded. The slider 24 engages in a recess 25 of the guide element 9 and lies with its two longitudinal sides 26, 27 ( Fig. 1 ) on the side walls 28, 29 of the recess 25 at.

On the support 8, two mutually parallel guide rails 30, 31 are fixed with the interposition of the guide element 9, which are penetrated by screws 32 or studs. Their heads or associated nuts 32 'are advantageous with the interposition of at least one plate spring 33 on the guide rails 30, 31. The bolts 32 and stud bolts pass through slots 34 in the guide element 9 and are screwed into the carrier 8. Due to the elongated holes 34, it is possible to adjust the guide element 9 relative to the carrier 8 and the guide rails 30, 31.

In this case, the guide element 9 is guided in a groove of the carrier 8 at its longitudinal sides 35, 36 in the horizontal plane and is adjusted without play in the vertical direction by the guide rails 30, 31 under load of the disc springs 33.

The slide 24 advantageously has two half-widths extending in its longitudinal direction slots 37, 38, which are at a small distance one behind the other. Through the slot 37 protrudes a screw 39, the head advantageously rests with the interposition of at least one washer 40 on the slider 34. With the screw 39, the slider 24 is mounted on the guide element 9. Due to the elongated holes 37, 38, the slider 34 can be adjusted in its longitudinal direction relative to the guide element 9.

On the holder 22 24 stops 41, 42 are provided in the area next to the slide, with which the displacement of the guide element 9 can be limited. The stops 41, 42 each have a holding plate 11 passing through screw 43, 44, each with a screw head 46, 48 in front of the holding plate 11 and in each case one seated on the screw nut 45, 47 (FIGS. Fig. 1 ) behind the holding plate 11. The screws 43, 44 continue to enforce the holder 22 and are connected thereto by means of the nuts 45, 47 and further, the holder 22 opposite nuts 45 ', 47' ( Fig. 2 ) fixed, but adjustable connected. With the pressure cylinder 12, the guide member 9 can be moved over the slider 24 so far until the nuts 45, 47 or screw heads 46, 48, depending on the direction of displacement, come to rest on the support plate 11. In the in the Fig. 1 and 2 shown position are the screw heads 46, 48 on the side facing away from the slider 24 outside of the holding plate 11 at. In this position, the splitting wedge 7 engages in the sawing gap, and the intermediate strips 63, 64 are on the left longitudinal side of the workpiece as a guide. In the opposite direction, the splitting wedge can be pushed back or moved so far until the nuts 45, 47 abut against the inside of the holding plate 11. This stroke between retracted and extended position can be adjusted by the above-described attachment of the screws 43, 44 on the holder 22, depending on how far the riving knife engages the kerf. As a result of the described setting of the switching distance of the sensor 17 and displacement of the carrier plate 14 in the oblong holes 19, the switching point of the sensor 17 is adjusted so that it leaves the detection range of the holder 22 before the nuts 45, 47 on the inside of the holding plate 11 for conditioning come and thus limit the stroke.

The guide element 9 carries the riving knife carrier 13, which is solid and stable and can be adjusted relative to the guide element 9. The riving knife carrier 13 is provided on its underside with a paragraph 49. The riving knife carrier 43 rests on the guide element 9 with the one surface 50 of the shoulder 49. With the adjoining the surface 50 shoulder surface 51 of the riving knife carrier 13 is located on the end face 52 of the guide member 9 at. The oblique position of the riving knife carrier 13 relative to the guide element 9 ensures that the riving knife device 6 can be brought close to the saw 3 without impairing the operation of the saw ( Fig. 1 ) and without coming into contact with the saw when driving back. In addition, this results in a directional component in the feed direction 5 of the workpieces 1, which kinematically is beneficial. The riving knife carrier 13 is penetrated by two elongated holes 54, 55, which are advantageously provided in half the width and are at a short distance behind each other. Both elongated holes 54, 55 are penetrated by screws 56, 57, with which the riving knife carrier 13 is releasably secured on the guide member 9. The screw heads are advantageous with the interposition of at least one washer 58 on the riving knife support 13. It can thus be adjusted in the longitudinal direction of the elongated holes 54, 55 relative to the guide element 9.

The riving knife carrier 13 is provided on its front side with a recess 59 which is open to the end face 60 and to the longitudinal side 61 of the riving knife carrier 13. In the recess 59 of the riving knife 7 is held between two strips 63 and 64, of which the lower strip 63 rests on the bottom 62 of the recess 59. The strips 63, 64 and the splitting wedge 7 lying between them are penetrated by two screws 65 with which they are fastened to the bottom 62 of the recess 59. The strips 63, 64 project beyond the front side 60 and the longitudinal side 61 of the riving knife carrier 13. In order for the splitting wedge 7 to be able to engage in the saw groove of the workpiece 1, it projects beyond the longitudinal side 61 of the splitting wedge support 13 further than the strips 63, 64 Fig. 2 only one riving knife 7 is shown. However, the riving knife carrier 13 has a number of splitting wedges 7 corresponding to the number of slats to be sawn, which are each separated from one another by the slats.

The end face 60 of the riving knife carrier 13 is at an acute angle to its longitudinal side 61, the opposite end face 66 at right angles to the longitudinal side 61 of the riving knife carrier 13 (FIGS. Fig. 1 ). As a result, the riving knife carrier 13 can be brought very close to the saw blades 3 of the left saw. The riving knife 7 can be adjusted in a manner to be described so that it only has a very small distance from the circle of the tool, for example, a distance of only about 3 mm. Because of this small distance between the splitting wedge 7 and the tool flying circle, only a few disturbances occur during sawing. Located in the wood Branches can not fall out because of this small distance between riving knife 7 and saw. Also solve less splinters and splinters from the workpiece. 1

The elongated holes 54, 55 extend in the installed position according to Fig. 1 parallel to the feed direction 5. As a result, the riving knife support 13 can be adjusted towards the tool so that the riving knife 7 only has the small described distance from the tool.

The riving knife 7 extends only over part of the length of the riving knife carrier 13 measured in the feed direction 5. Because of the small length, the riving knives 7 can be easily handled and produced at low cost. Thus, the riving knife 7 and the intermediate strips 63, 64 can be easily and accurately positioned in the recess 59 of the riving knife carrier 13, the subsequent to the longitudinal side 61 flat bottom 67 of the recess 59 serves as a bearing surface for the riving knife 7 and the intermediate strips 63, 64th You can also be brought to the adjoining the bottom 67 side wall 68 of the recess 59 for conditioning. The splitting wedges 7 and intermediate strips 63, 64 can be quickly changed due to this training when setting the splitting wedge device 6 to a new machining task. Also, corrections and the insertion of pass plates can be performed quickly and easily. Due to the very short splitting wedges 7, the friction between them and the workpiece 1 is considerably reduced. As a result, very high feed rates can be driven.

In the illustrated embodiment, the length of engaging in the workpiece 1 part of the splitting wedge 7 is less than half the length of the riving knife carrier 13, preferably only about one third of this length.

The carrier 8 can be adjusted exactly parallel to the feed direction 5 on the machine stand or the spindle slide relative to the tool used. The slider 24 can be in its longitudinal direction by means of Adjust screw 39 and the slot 37 stepless relative to the guide member 9. Since the riving knife carrier 13 can be adjusted relative to the guide element 9, the riving knife 7 can be optimally adapted to the respective circle diameter of the tool used and the width of the workpiece 1 to be machined without affecting the switching point of the proximity sensor 17. The slide 24 with the holder 22 remain after the initial default always in the same position to the sensor 17th

The entire riving knife device 6 is pressed into the kerf by means of the pressure cylinder 12, i. the splitting wedges 7 are reliably pressed into the sawing gaps of the workpiece 1. The intermediate strips 63, 64 act as a limitation for the penetration depth of the splitting wedges 7 in the respective kerf. In addition, the intermediate strips 63, 64 guide the workpiece 1 during its transport through the machine by the workpiece 1 is guided fitting on their long sides.

The riving knife carrier 13 itself can be positioned in a simple manner on the guide element 9, since the surface 51 of the shoulder 49 is brought into contact with the end face 52 of the guide element 9.

The pressure cylinder 12 generates a resilient contact force on the riving knife 7. If a fault occurs by splinters, splinters or loose branches in the sawing gap hit the riving knife 7, the entire riving knife device 6 is pushed back so far that the riving knife 7 is released from the sawing gap.

The splitting wedge device 6 is adjusted so that the proximity sensor 17 is opposite the adjacent end face 69 of the holder 22 (FIG. Fig. 1 and 2 ). If the riving knife device 6 is pushed back due to disturbances in the saw gap, the holder 22 passes outside the detection range of the sensor 17. It triggers a switching pulse, which is given to a controller. With her it is possible, for example, the feed for the Stop workpiece 1 and / or switch off saw spindle 2. In this way, damage to the splitting wedge device 6, the saw spindle 2, the tool 3 or other machine parts is avoided. Further, by the switching pulse of the riving knife 7 can be completely adjusted by the switching of the pressure cylinder 12 to the end position, whereby the risk that the riving knife device 6 is damaged by the disturbance, is even lower.

In an alternative arrangement of the sensor 17, this can also be provided so that in the normal position of the riving knife device 6, d. H. when the cylinder 12 is extended, the holder 22 is outside the detection range of the sensor 17 and this is not switched. When pushing back the splitting wedge, the holder 22 then enters the detection range of the sensor 17, whereby the switching pulse is triggered.

As a result of the described embodiment and setting of the holder 22 is set regardless of the workpiece width and / or the circle diameter of the saw exactly on the proximity switch 17. The switching point is thus always the same regardless of the workpiece width or the circle diameter, whereby the riving knife device 6 can be adjusted quickly and easily to different workpiece widths and circle diameter.

The described splitting wedge device 6, which is associated with the left saw, generates the described elastically yielding contact pressure. Also, the right saw is associated with a riving knife device, however, is arranged transversely to the transport direction 5 of the workpieces 1 not by spring force, but rigidly in relation to the stop. This splitting wedge device 6 can also be adjusted parallel to the feed direction 5 in the direction of the right saw to allow adaptation to different sized circle diameter of this saw.

The riving knife device can be used for feed speeds up to about 70 m / min, saw blade pitch diameter from about 250 mm to about 400 mm and for workpiece widths from about 50 mm to about 150 mm. The splitting wedges 7 can each be set very close to the tool circle. Advantageously, this distance to the circle diameter is only about 3 mm.

Claims (11)

1. A riving knife device for a saw unit, having riving knives (7) that in a working position engage in sawcuts in the workpiece (1) being sawn and are provided on a riving knife support (13), which is placed under load resiliently in the working position by means of a drive unit (12),
   characterized in that the riving knives (7) on the riving knife support (13) are arranged one on top of the other and separated from each other intermediate bars (63, 64) that lie between the riving knives, that the riving knives (7) and the intermediate bars (63, 64) are secured to the riving knife support (13), and that at least one sensor (17) is assigned to the riving knife support (13), which sensor sends a signal to a controller when the riving knives (7) are pressed out of the respective sawcut.
2. The riving knife device according to claim 1,
   characterized in that the riving knife support (13) is connected to at least one guide element (9), which is displaceable via the drive unit (12) relative to at least one carrier (8).
3. The riving knife device according to claim 2,
   characterized in that the drive unit (12) is equipped with a pressing cylinder that is rigidly connected to the carrier (8).
4. The riving knife device according to claim 3,
   characterized in that a piston rod (23) of the pressing cylinder (12) is connected in driving manner to the guide element (9) via a retainer (22) and a slider (24) connected thereto.
5. The riving knife device according to any one of claims 2 to 4,
   characterized in that the guide element (9) supports a slider (24) that can be adjusted and fixed in position relative to the guide element (24).
6. The riving knife device according to any one of claims 2 to 5,
   characterized in that the guide element (9) is adjustable in the direction of the workpiece (1) relative to the carrier (8).
7. The riving knife device according to any one of claims 1 to 6,
   characterized in that the sensor (17) is an inductive proximity sensor.
8. The riving knife device according to any one of claims 4 to 7,
   characterized in that the sensor (17) is secured on the carrier (8), and cooperates with the retainer (22) secured on he slider (24) of the guide element (9).
9. The riving knife device according to any one of claims 1 to 8,
   characterized in that the length of the riving knives (7) is shorter than the length of the riving knife support (13).
10. The riving knife device according to any one of claims 3 to 9,
    characterized in that the extended and retracted positions of the pressing cylinder (12) are adjustable and are limited by fences (41, 42).
11. The riving knife device according to any one of claims 1 to 10,
    characterized in that the riving knives (7) are adjustable close to a tool (3, 4).

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