EP2556921A2 - Methods for sharpening, in particular sharpening knives of a knife ring flaker - Google Patents

Abstract

The method involves fastening multiple knife holders (9) at a rotating knife ring (2). Knives (6) are held at the holders by clamping. The knives to be sharpened are advanced in/at the holders without releasing the clamping, and subsequently ground by a grinding device i.e. belt grinding device, in an advanced position. Clamping plates of the holders are connected with holding plates by clamping screws (10). The knives are fixed between the holding plates and the clamping plates by the clamping screws. The knives are polished in the advanced position upto a preset management measure. An independent claim is also included for a device for resharpening knives of a knife ring flaker.

Description

The invention relates to a method for sharpening, in particular re-sharpening knives of a Messerringzerspaners in which a knife ring several knife holder are attached to which at least one knife is held by clamping, the sharpened knife to be advanced in / to the knife holder and then in the advanced position be ground with a grinding device.

Messerringzerspaner serve the production of chips or the like material for the production of wood-based panels, such as chipboard or the like. The raw wood is usually supplied as bulk material, for example in the form of wood chips. Such a Messerringzerspaner has a knife ring on which a plurality of knives (in / on) knife holders are attached. The knife holder is composed, for example, of a holding plate and a clamping plate connected to the holding plate via at least one clamping screw, the knife being fixed with the clamping screw between the holding plate and the clamping plate. Messerringzerspaner means within the scope of the invention but not only a chipper for wood chips, in which, in addition to the rotating blade ring optionally still a counter-rotating inner guide ring is provided, but also chipper for long wood.

Since the blades of a chipper are heavily subject to wear, it is necessary at regular intervals to sharpen the blades of a Messerringzerspaners and therefore nachzuschärfen. This is done by way of grinding. For this purpose, first of all the knife ring from the Removed knife ring chipper. While it was previously necessary to remove the individual knives for regrinding the knife ring, devices are now used, with which it is possible to leave the knife during grinding in the knife ring.

A method for sharpening or re-sharpening knives of a Messerringzerspaners of the type described above, in which the blades can remain in the knife ring during regrinding, for example, from DE 43 16 514 C2 (or the corresponding EP 0 626 234 B1 ) known. The sharpening of the knives is done by grinding their installed in the knife carrier state under the slow rotation, wherein prior to sharpening all the knives loosened successively in their holder and advanced by an amount corresponding to the cutting wear in their effective range. In this advanced position, the knives are re-clamped and then pre-programmed to achieve a desired cutting board on the relevant surface of the knife carrier radial grinding feed, taking into account the state of wear of this area. In the grinding device used is a grinding device with a grinding wheel, which is driven by a drive motor by means of belt drive. This is mounted on a support which is movable by means of a cross slide in the axial and radial directions. To advance the individual knives up to the knife stop defined by a position sensor, a tool combination is used which is mounted on a tool stand. This tool combination initially has a screw for loosening and re-tightening the clamping screws on the knife holder and a knife ram for each advancing the Zerspanmesser. Furthermore, a hold-down is provided, which is the Ruhigstellen the loosened knife holding plates worried during the individual knife feeds. All tools are programmatically pneumatically operated.

A comparable procedure is from the EP 0 875 338 B1 known. The knife ring or knife basket has a plurality of knife packages, each having a support block, a clamping plate, a knife located between these two and a clamping screw and a wear plate. As soon as the knives no longer have the necessary sharpness, the entire knife basket is removed from the chipper by means of a conditioning device. Then, a grinding device is inserted into the space enclosed by the knife basket interior. In this case, the grinding device is positioned such that each grinding wheel is opposite to a knife to be ground. The grinding device thus has a plurality of grinding wheels.

Finally, one knows from the DE 695 01 961 T2 (or the corresponding EP 0 775 043 B1 ) a clamping system for knives of a Zerspaners, which is designed as Langholzzerspaner. The surfaces of the clamping means and / or the holder may have a wave profile, wherein this surface is deformable with wave profile, so that it engages when tightening the screws with a predetermined force on the cutting means with a substantially uniform clamping force.

The known Messerringzerspaner have proven in principle in use in practice. However, the resharpening of the knives is still associated with great expense. - This is where the invention starts.

The invention has for its object to provide a method of the type described above, which allows a simple way, a speedy and proper sharpening and especially re-sharpening a Messerringzerspaners.

To solve this problem, the invention teaches in a generic method, in particular re-sharpening knives of a Messerringzerspaners that the knives are advanced into / on the knife holder without loosening the clamp. If the knife holder has at least one holding plate and a clamping plate connected to the holding plate via at least one clamping screw, in which the knife is fixed with the clamping screw between holding plate and clamping plate, the invention proposes that the knife is advanced without loosening the clamping screw.

The invention is based on the surprising finding that the blades of a Messerringzerspaners for the purpose of regrinding readily with suitable means can advance without the clamping must be solved in the knife holder. The invention therefore proposes, in diametrical departure from the known method, to dispense with a release of the clamping and to advance the knives for the purpose of re-sharpening consequently in the clamped state by a desired degree. This can be dispensed with the elaborate loosening of the clamping screws with the appropriate apparatus required, so that the regrinding of the knife can be done inexpensively and quickly.

The knife is preferably advanced with a (mechanical) feed device and particularly preferably a controlled feed device. In this case, the feed preferably continuously and consequently pushing or pushing be realized by continuously or quasi continuously a certain feed force in the longitudinal direction of the knife is applied to the knife. Surprisingly, can be overcome by the sliding processing, the high clamping forces and advance the knife in a desired position. For this purpose, electromotive or pneumatic or hydraulic feed drives press by means of feed elements on the back of the knife. Alternatively, the knife is advanced pulsating or beating, for example, with a pulsating or whipping driven or operating feed device. Such a beat feed device is also suitable to advance the knife itself against high clamping forces without loosening the clamp in the desired manner. Such a pulsating or impact driven feeding device can be equipped, for example, with a striking mechanism, as known for example from beaters or drills. The feed device can be pneumatically or hydraulically driven to initiate the high feed forces against the clamping in the knife can. Alternatively or additionally, electromotive drives, for example spindle drives, are possible, especially when working continuously.

Controlled feed means in the context of the invention, in particular, that the feed force is not manually, but mechanically applied in a certain defined manner, for example with defined forces and / or over defined time intervals. In principle, it is possible to monitor the realized feed metrologically. However, this is not mandatory.

In a preferred embodiment of the invention, it is proposed that the knife be ground in the advanced position to a predetermined board size. The invention is based on the recognition that it is not absolutely necessary to realize an exact board when advancing the knife. Rather, can be dispensed with an exact positioning, if subsequently after the feed of the desired board is realized by appropriate grinding of the knife. Consequently, even with high clamping forces can be dispensed with the release of the clamping, and in particular also because it is not necessary within the scope of the invention that is maintained in the context of the feed of the exact board.

The resharpening of the individual knives preferably takes place after the knife ring has been removed from the knife ring scraper. This is especially true in Messerringzerspanern for the cutting of wood chips or the like, in which within the knife ring a likewise rotating, for example, counter-rotating guide ring is arranged, which brings the chips via the centrifugal force in the range of the knife. Messerringzerspaner means within the scope of the invention but also chipper for Langholzzerspanung in which the long wood is introduced into the Zerspanungsraum within the blade ring, without there being a rotating guide ring is provided.

After the knife ring has been removed from the chipper in the preferred embodiment, the resharpening of the knife can basically be done in a "stationary" orientation of the knife ring by the knife ring is fixed, for example standing in a suitable holder. However, the blades are preferably in a lying position befindendem Knife ring advanced and ground. In this lying position, high feed forces can be easily applied, without deformation of the knife ring or other disturbances are to be feared. It is expedient to fix the knife ring in the lying position, for example with a suitable fastening device. The processing in a lying position also has the advantage that the grinding device can be inserted from above into the knife ring, so that the abrasive particles or the grinding dust can be easily removed down. In the context of the invention, it is preferably possible to work by dry grinding, for example with a belt sander. Coolants required in wet grinding can thus be dispensed with in this preferred embodiment.

Furthermore, the invention proposes that the board of the knife is measured during and / or after the loops. This is particularly useful if - as described above - the feed is not previously measured exactly, but the desired board is then set during grinding. However, the measurement does not have to be done with special measuring devices that work directly on the knife, but preferably succeeds the measurement of Messervorstandes indirectly by appropriate control of the grinding device by the grinding device in the radial direction in the course of grinding is advanced so far that set the desired Messerervorstand becomes.

The invention also relates to a device for sharpening, in particular re-sharpening knives of a Messerringzerspaners, according to a method of the type described. Such a device has at least one feed device for advancing the knife in / on the Knife holders and a grinding device for grinding the knife. The device, which preferably has a feed ram or feed ram, is characterized in that the feed device for advancing the knives is set up without loosening the clamp. This can be a continuously operating feed device or a pulsating or impacting feed device. The grinding device is preferably designed as a belt grinding device, which preferably operates without coolant. The feed device can be provided with a pushing electromotive, hydraulic or pneumatic drive. Alternatively, a beating drive can be provided. The drive works on the ram or punch, which in turn works on the knife.

Fig. 1

einen Messerringzerspaner in einer perspektivischen Darstellung,

Fig. 2

ausschnittsweise einen aus dem Messerringzerspaner ausgebauten Messerring,

Fig. 3

eine Vorrichtung zum Schleifen der Messer in perspektivischer Darstellung in einer ersten Funktionsstellung,

Fig. 4

den Gegenstand nach Fig. 3 in einer zweiten Funktionsstellung,

Fig. 5

den Gegenstand nach Fig. 4 in einer dritten Funktionsstellung und

Fig. 6

den Gegenstand nach Fig. 5 in einer vierten Funktionsstellung,

Fig. 7

den Gegenstand nach Fig. 6 in einer Seitenansicht,

Fig. 8

den Gegenstand nach Fig. 6 in einer anderen Seitenansicht,

Fig. 9

den Gegenstand nach Fig. 6 in einer Draufsicht und

In the following the invention will be explained in more detail with reference to a drawing illustrating an embodiment. Show it

Fig. 1

a Messerringzerspaner in a perspective view,

Fig. 2

partially a knife ring removed from the Messerringzerspaner,

Fig. 3

a device for grinding the knives in a perspective view in a first functional position,

Fig. 4

the object after Fig. 3 in a second functional position,

Fig. 5

the object after Fig. 4 in a third functional position and

Fig. 6

the object after Fig. 5 in a fourth functional position,

Fig. 7

the object after Fig. 6 in a side view,

Fig. 8

the object after Fig. 6 in another side view,

Fig. 9

the object after Fig. 6 in a plan view and

In Fig. 1 is a cutting machine in the embodiment as a knife ring chipper for the cutting or crushing of wood, especially for the production of wood chips or the like material shown. In a housing 1, on the one hand, a rotating (outer) blade ring 2 and on the other hand arranged a rotating within the blade ring 3 beater. Both the knife ring 2 and the beater wheel 3 are driven by suitable shafts. Details are not shown. As a rule, knife ring 2 on the one hand and beater wheel 3 on the other hand rotate in opposite directions. Fig. 1 shows the Messerringzerspaner frontally open housing, so that in particular the blade ring 2 and the beater wheel 3 are visible inside. The wood is supplied as bulk material, eg in the form of wood chips. It passes through an upper feed chute 4 and corresponding front-side deflection 5 in the interior of the Messerringzerspaners and consequently in the interior formed within the Schlägerrades 3. In Fig. 2 is fragmentary illustrated the knife ring 2 in the disassembled state in the region of a processing device. It has two axially spaced annular discs 2a, between which a plurality of knife carriers 2b are attached. It can be seen that each blade carrier 2b is equipped on the one hand with a knife 6 and on the other hand with a wear plate 7, wherein the Wear plates are also referred to as wear shoes 7. The wear plates 7 are mounted on the inside of the knife ring in tangential alignment. With their inner surfaces 8, they form the inner surface of the knife ring 2. The knives 6 are arranged at a predetermined angle α relative to the wear plates 7. In each case, the knives protrude above the inner surface 8 of the wear plate 7 between two adjacent wear plates 7 with a predetermined knife edge. Messervorstand here means the Messervorstand set for the operation. The knives 6 are attached exchangeably to knife holders 9. For this purpose, clamping screws 10 are provided, with which the knives 6 are clamped to the knife holders. The knife holder 9 can be composed of eg holding plate and clamping plate. The knives 6 of the knife ring 2 must be resharpened or reground at regular intervals. For this purpose, the blade ring 2 from the Messerringzerspaner according to Fig. 1 expanded and in the in the Fig. 3 - 9 shown processing device 11 introduced. Part of this processing device 11 are on the one hand a grinding device 12 and on the other hand a turntable 13, on which the removed knife ring is attached, in such a way that the knife ring 2 with or on the turntable 13 is rotatable. In the exemplary embodiment it is provided that the grinding device 12 is movable relative to the turntable 13 and the blade ring 2 mounted thereon in the axial and radial directions, with respect to the axis A of the blade ring.

The Fig. 3 to 6 show the processing device 11 in different functional positions. The background is the fact that the knife ring 2 is removed from the knife ring chipper in a vertical arrangement and then processed in the processing device 11 in a horizontal arrangement. To enable this in a simple manner, the turntable 13 and the Grinding device 12 is arranged on a pivoting table 24, wherein the pivoting table 24 is pivotally mounted on a machine frame 14 for tilting the knife ring 2 from an extended position with a horizontal axis in a machining position with a vertical axis about a horizontal axis 29. Structure and operation of this arrangement with pivot table resulting from a comparative analysis of Fig. 3 to 6 , in which Fig. 6 shows the processing device 11 with knife ring 2 in the horizontal processing position, in which the grinding is done by means of the grinding device 12.

First, the knife ring from the Messerringzerspaner according to Fig. 1 removed and extended with the help of there recognizable expansion rods 32 from the Messerringzerspaner. From there it can be supplied, for example, with a separate (not shown) Dolly the processing device 11.

Fig. 3 shows the processing device first with horizontally arranged pivoting table 24 without mounted blade ring. From this first functional position, the processing device is first in the in Fig. 4 shown converted second functional position, wherein the pivot table is arranged vertically here. In this functional position, the knife ring 2 can now be taken over by the transport carriage, not shown, or the like. For this purpose, the processing device on the machine frame 14 on two support rods 31, which are retractable and extendable, and consequently are movable in the horizontal direction, so that they can take over the standing knife ring and drive against the pivoting table 24. This results from a comparative consideration of Fig. 4 and 5 , The knife ring 2 is thus adopted in a standing arrangement in the processing device 11 and then fixed to the turntable 13. For this purpose, the turntable 13 has a plurality of fastening elements 30. After the knife ring 2 has been fixed to the turntable 13, the pivot table 24 can be pivoted about the horizontal axis 29 by means of the pivot drive 25, so that the pivot table 24 from the vertical position to the horizontal position and thus the knife ring from the standing position in the lying position is transferred, in which the axis of the knife ring is vertically aligned. This results from a comparative consideration of Fig. 5 and 6. Fig. 6 Consequently shows the processing device 11 with mounted blade ring 2 in the machining position, in which the blade ring is in a horizontal arrangement with vertically aligned axis A.

Of particular importance is the fact that the grinding device 12 is arranged on the pivot table 24, but relative to the turntable 13 in the axial direction and radial direction (relative to the axis A of the rotary table mounted on the knife ring) is movable. After the knife ring 2 consequently in the in Fig. 6 shown position on the turntable 13, the grinding device 12 can be lowered in the axial direction Y, so that it dips into the blade ring 2. The grinding of the knife 6 is preferably carried out while the grinding device 12 is running by slowly rotating the knife ring 2 around the grinding device 12 around. By positioning the grinding device 12 relative to the knife ring 2 in the radial direction X, the grinding operation can be controlled. In the illustrated embodiment, this is structurally realized in that on the pivoting table 24, a carrier carriage 15 is arranged, wherein the carrier carriage 15 is movable relative to the machine frame and consequently relative to the pivot table in the radial direction X and consequently positionable. In the exemplary embodiment, linear guides 16 are provided for this purpose. On the carrier carriage 15 is a Fixed holding device 17 for the grinding device, in such a way that the holding device 17 in the axial direction Y on the carrier carriage 15 is movable. This means that the holding device 17, to which in turn the grinding device 12 is attached, can be raised and lowered. For this purpose, vertically oriented linear guides 18 are provided between carrier carriages 15 and holding device 17. For the turntable 13, a merely indicated rotary drive 19 is provided. The grinding device 12 is designed as a belt grinding device. It has a grinding drive 21 for driving the grinding belt 20. The grinding device 12 or its holding device 17 is movable on the carrier carriage 15 by means of a lifting drive 22, for example, raised and lowered. In addition, a merely indicated feed or feed drive 23 can be provided, with which the grinding device 12 or the carrier carriage 15 can be moved in the radial direction X. Incidentally, it can be seen that the pivoting table 24 with a pivot drive 25 is pivotable about the pivot axis 29.

Furthermore, it can be seen in the figures that a knife feed device 26, which has a plurality of knife feed elements 27, is fastened to the swivel table 24. With these feed elements 27, which may be formed, for example, as feed rods, the individual knives of the knife ring can be advanced by a desired amount. For it is expedient if the knives are advanced by a certain amount before grinding by means of the feed device 26. For this purpose, the feed device 26 has two feed drives 28 assigned to the feed rods 27. The feed rods, as it were, pass through the knife carriers from behind by means of already provided grooves, so that they work from the rear of the knife onto the knives. The advantage here is the fact that the feed device 26 fixed (but optionally adjustable) on the Swiveling table is arranged. The turntable on the one hand with the attachment points 30 for the knife ring and the advancing device 26 on the other hand are thus fastened to each other in a fixed predetermined arrangement on the pivot table, so that their relative position, especially during pivoting of the pivot table 24, does not change.

According to the invention, the feed device 26 operates without releasing the clamping of the blades and consequently without loosening the clamping screws. The knives are thus advanced with the advancing elements 27 via their drives 28 without loosening the clamping. For this purpose, the knife ring is brought by means of the rotary drive in a certain position and advanced a single knife. Then the ring can be rotated further by a certain angle and the next knife can be advanced. Preferably, first all knives are advanced by a certain amount. Subsequently, then the grinding of all the knives can be done with rotating knife ring by means of the grinding device. An interesting aspect is the fact that the desired knife edge in the course of grinding can be done by suitable control of the grinding device and in particular the positioning of the grinding device. The advance of the blades must therefore not be in an exact position, but it is sufficient if the blades are advanced by a certain minimum. After all, the desired knife edge is only apparent after the grinding process.

After the grinding process, the pivot table 24 can again in the in Fig. 5 pivoted position shown and removed the knife ring and re-installed in the knife ring chipper 1.

As an alternative to the procedure described, however, it is also within the scope of the invention to advance the knives one after the other and to sharpen them directly. In this variant, therefore, not worked with rotating knife ring, but the grinding is done with the knife ring. This is particularly useful when you want to sharpen knives with clearance angle.

Claims (15)

Method for sharpening, in particular re-sharpening knives of a knife ring chipper, in which a plurality of knife holders are fastened to a knife ring, on each of which at least one knife is held by clamping,
wherein the knives to be sharpened are advanced in / on the knife holder and then ground in the advanced position with a grinding device, characterized
that the blades are advanced in / on the blade holder without releasing the clamping. A method according to claim 1, wherein the knife holder has at least one holding plate and a clamping plate connected to the holding plate via at least one clamping screw, wherein the knife is fixed with the clamping screw between holding plate and clamping plate, characterized in that the knife is advanced without loosening the clamping screw. A method according to claim 1 or 2, characterized in that the knife is abraded in the advanced position to a predetermined board size. Method according to one of claims 1 to 3, characterized in that the knife is advanced with a controlled feed device. A method according to claim 4, characterized in that the knife is pushed forward with a continuously driven feed device. A method according to claim 4, characterized in that the knife is advanced beating with a pulsating driven feed device. Method according to one of claims 1 to 6, characterized in that the knives are advanced and ground in a knife ring located in a lying position. Method according to one of claims 1 to 7, characterized in that the board dimension of the knife before, during and / or after grinding is measured. Device for sharpening, in particular re-sharpening knives of a knife ring chipper (1), according to a method according to one of claims 1 to 8,
with at least one knife feed device (26) for advancing the knife (6) in / on a knife holder and
at least one grinding device (12) for grinding the knife (6), characterized in that
the feed device (26) is arranged for advancing the knife (6) without loosening the clamp. Apparatus according to claim 9, characterized in that the feed device (26) is equipped with continuously driven feed elements (27). Apparatus according to claim 10, characterized in that the feed device (26) is equipped with pulsating driven feed elements (27). Device according to one of claims 9 to 11, characterized in that the feed device (26) has at least one drive (28) which operates on a feed element (27), for example on at least one feed punch or Vorschubstößel, wherein the drive (28) is designed as a hydraulic drive, pneumatic drive and / or electromotive spindle drive. Device according to one of claims 9 to 12, characterized in that the grinding device (12) is designed as a belt grinding device. Device according to one of claims 9 to 13, characterized by a turntable (13) on which the knife ring is fastened such that the knife ring (2) is rotatable in a vertical arrangement with vertically oriented axis relative to the grinding device (12). Apparatus according to claim 14, characterized in that the grinding device (2) relative to the turntable (13) and / or the turntable (13) relative to the grinding device (12) in the axial direction and radial direction - with respect to the axis of the Turntable (13) attached knife ring (2) - is movable.

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