The instant application should be granted the priority date of May 20, 2008 the filing date of the corresponding German patent application 10 2008 024361.2.
The present invention relates to a longitudinal cutting or slitting machine having disposed thereon knife carriers for a circular knife respectively held thereon, whereby the circular knife is pre-tensioned or preloaded by a pre-tensioning element disposed on the knife carrier into its cutting position defined by abutment of the circular knife against a counterknife.
A knife carrier provided for a longitudinal cutting or slitting machine and having the aforementioned features is known from DE 202 01 744 U1. With the blade holder described in this document, the circular knife, which is mounted on a hub formed on the knife carrier, is pre-tensioned by a knife spring to rest against the counterknife, whereby the knife spring is comprised of two leaf springs that are placed against one another, are inserted on the hub, and are supported against the knife carrier.
To the extent that with a knife carrier embodied in this fashion the circular knife can respectively deflect against the effect of the knife spring, a construction of knife carriers is also known according to which the circular knife is disposed against the knife carrier in a fixed position and thus rests in an unmovable manner against a counterknife. Such a knife carrier Is described, for example, in EP 0 113 668 A1, according to which the circular knife is fixedly clamped against the knife carrier.
To the extent that operational situations exist in which one or the other manner of operation of the circular knife is expedient, it is an object of the present invention to configure a longitudinal cutting or slitting machines having a knife carrier of the aforementioned general type in such a way that it is possible to have both the manner of operation where the circular knife is under pre-tension, in particular being spring-loaded, as well as the manner of operation where the circular knife is fixed or secured in position.
This object, and other objects and advantages of the present invention, will appear more clearly from the following specification in conjunction with the accompanying schematic drawings, in which:
a & 2b are partial views of the subject matter of
a & 4b show a further embodiment of the knife carrier of
a and 5b show an alternative embodiment to the embodiment illustrated in
a and 6b show an embodiment of the knife carrier with a changeover mechanism embodied as a pressure distribution ring in the two functional positions of
The basic concept of the present invention is that by means of a changeover mechanism disposed on the knife carrier, the pre-tensioning element can be placed in an ineffective position that provides a firm connection between the knife carrier and the circular knife. The longitudinal cutting machine of the present application has the advantage that the construction of the knife carrier permits both manners of operation with a circular knife that is under pre-tension or pre-load as well as with a circular knife that is fixed in position, and it is merely necessary to activate a single changeover mechanism that is configured on the knife carrier in order to selectively shift back and forth between the two manners of operation.
Pursuant to one embodiment of the invention, the installed changeover mechanism can also be used to realize a variable adjustment or setting of the pre-tension that acts upon the circular knife. For this purpose, by means of the changeover mechanism, with the pre-tensioning element made to be effective by the changeover mechanism, a variable adjustment of the pre-tensioning force of the pre-tensioning element is provided.
Pursuant to a first embodiment of the invention, the pre-tensioning element is embodied as a knife spring that is supported against the knife carrier and pretensions the circular knife into its cutting position. Further embodiments of the invention are directed either to activating the effect of the installed knife spring, or to entirely deactivate it, or to make the spring force exerted by the knife spring variably adjustable.
With regard to an activation and deactivation of the knife spring, pursuant to a first embodiment of the invention disposed on the knife carrier is at least one axially displaceable fixation pin that acts upon the circular knife, with the knife spring that is supported against the knife carrier pressing the fixation pin in its spring-loading position under pre-tension against the circular knife, whereby the changeover mechanism is configured for the fixing of the fixation pin in position in its stationary secured position against the knife carrier. This solution thus proceeds from the holding of the circular knife against the knife carrier by means of at least one fixation pin that is axially displaceable in the knife carrier, whereby the axial displaceability of the fixation pin that is under spring effect on the one hand enables the manner of operation with a spring-loaded circular knife, whereas the fixation pin that is stationarily fixed in position by means of the changeover mechanism in its secured position brings about the manner of operation with a circular knife that is secured in position on the knife carrier.
To realize this principle, the circular knife can be mounted on a hub formed on the knife carrier, and fixation pin, knife spring as well as changeover mechanism can be disposed on an annular nut that is disposed on the hub. In detail, this provides that fixation pin and knife spring are disposed on that side of the circular knife facing away from the counterknife, and disposed on the knife carrier, as the changeover mechanism, is a rotatable apertured plate that in its one position is aligned with the fixation pin via an opening formed on the apertured plate, and in its other position rests against the fixation pin and fixes it in position.
In an alternative embodiment, a circular knife is mounted on a hub formed on the knife carrier and is held against the knife carrier by the fixation pin, which is held on the knife carrier and is disposed on that side of the circular knife associated with the counterknife, whereby in its spring-loading position, the fixation pin is displaceable against the effect of the knife spring disposed in the knife carrier, and in its secured position is adapted to be fixed in position by means of the changeover mechanism that is disposed on the knife carrier.
In this connection, the fixation pin can be connected with a lock nut that is displaceably disposed in a recessed portion disposed in the knife carrier, and the lock nut can be pre-tensioned by the knife spring disposed in the recessed portion into a position that effects the spring-loaded abutment of the fixation pin against the circular knife, whereby pursuant to one embodiment of the invention, the changeover mechanism is embodied as an orifice plate that fixes the position of the lock nut in a stationary position of the fixation pin with fixed abutment against the circular knife. Pursuant to one embodiment, the orifice plate can be rotatably disposed on the knife carrier and can engage the lock nut by means of an extension that extends into the recessed portion of the knife carrier.
If pursuant to one embodiment of the invention the knife spring is embodied as a pre-tensioned helical compression spring that is supported between the knife carrier and the fixation pin, the arrangement of a helical compression spring that surrounds the respective fixation pin enables a reduction in construction relative to the leaf spring arrangement that is conventional in the art.
Pursuant to one embodiment of the invention, for symmetry reasons a plurality of fixation pins are disposed on the knife carrier and are distributed over the periphery of the circular knife.
A variable adjustment of the respectively acting spring force of the knife spring, up to its entire deactivation, can be realized pursuant to an embodiment of the invention if the circular knife is mounted on a hub formed on the knife carrier and is secured by means of an annular nut disposed on the hub, whereby the changeover mechanism is integrated into the annular nut. In particular, the annular nut can be divided by a plane of separation into two annular nut sections that are movable relative to one another in such a way that a rotation of the annular nut sections relative to one another brings about an axial displacement of one of the annular nut sections along with an axial enlargement of the width of the annular nut. By means of this alteration of the axial overall width of the annular nut, an adjustment of the spring force proceeding from the knife spring is ultimately possible.
Pursuant to embodiments of the invention, for this purpose the plane of separation formed on the annular nut can be configured as an inclined plane that extends in the axial direction between the annular nut sections. Alternatively, the plane of separation that is formed on the annular nut can be configured with a contour that is wave shaped in the peripheral direction and in the axial direction of the annular nut forms wave peaks and wave troughs. In both cases, when the annular nut sections rotate relative to one another, the two annular nut sections run against one another along their plane of separation, leading to the axial displacement of one of the two sections.
With regard to the configuration of the knife spring, pursuant to one embodiment of the invention the knife spring is embodied as a set of springs that includes at least two leaf springs that are placed against one another and are disposed on a hub, and that is disposed between the annular nut and the circular knife, whereby the pre-tensioning force of the set of springs can be variably adjustable by axial displacement of the annular nut sections.
Also within the scope of such an arrangement with an appropriately split annular nut, an embodiment of the invention can be provided where the knife spring can be activated or even entirely deactivated. In this connection, the knife spring is embodied as a cord spring that sits on an inclined plate that is disposed on the knife carrier and is inclined in the direction of the circular knife, whereby the annular nut section that faces the circular knife, when it is displaced axially, passes via a shoulder into abutment against the circular knife and fixes the circular knife in position.
Alternatively, for the configuration of the pre-tension element as a mechanically operating spring, pursuant to an embodiment of the invention the pre-tensioning element is embodied as a pressure distribution ring that is disposed on a knife carrier and has a plurality of axially movable pistons that are distributed over its periphery and are intended for abutment against the circular knife; the pistons are connected to a uniform pressure chamber for a fluid that is to be introduced therein. Such a pressure distribution ring is known, for example, from DE 10232772 B3.
If the pressure of the fluid present in the pressure chamber of the pressure distribution ring is variably adjustable by means of the associated changeover mechanism, then on the one hand the pressure in the pressure chamber of the pressure distribution ring can be set to such a value that during the cutting operation a circular knife that deflects against the action of the pistons presses the pistons into the pressure distribution ring until the pressure set in the pressure chamber is reached. If the pressure in the pressure chamber in the pressure distribution ring is set so high that a pressing-in of the pistons by the circular knife is no longer possible, the manner of operation is configured for a circular knife that is fixed in position.
Pursuant to a modified embodiment, the pre-tensioning element can be embodied as an inflatable hose that is disposed on the knife carrier and that is supported between the circular knife and an abutment disposed on the knife carrier. In this connection, the support against the circular knife can be realized directly by abutment of the hose against the circular knife, or indirectly via the interposition of a suitable component. Also with this embodiment it is possible, by regulating the inflation hardness of the hose, to set the pressure in the hose in such a way that on the one hand during the cutting operation the circular knife deflects to the desired extent, and on the other hand the circular knife is fixed in position by a hose that is inflated to an appropriately hard extent.
It is possible to employ the present invention with all types of knife carriers, and in particular with a knife carrier that is part of a knife head provided on a knife holder disposed on the longitudinal cutting or slitting machine, or, alternatively, with a knife carrier that is a jacket or box disposed on the longitudinal cutting or slitting machine. However, the aforementioned examples of application do not limit the realization of the invention in a technical regard.
Further specific features of the present application will be described in detail subsequently.
Referring first to
As can be seen from
On the rear side of the annular nut 13 that faces away from the circular knife 11, an apertured plate 18 is rotatably mounted on the annular nut 13. The apertured plate 18 has an opening 19 that is disposed in such a way that in one position of rotation of the apertured plate 18 the opening 19 is in an aligned position with the fixation pin 14 in which the head 15 of the fixation pin can pass through the opening 19 as illustrated in
Thus, if the apertured plate 18 is in a position in which its opening 19 is aligned with the head 15 of the fixation pin 14, as illustrated in
However, if the apertured plate 18 is in a position of rotation in which the opening 19 is rotated relative to the fixation pin 14, as illustrated in
If the extension 23 of the orifice plate 22 is not in engagement with the lock nut 21, the fixation pin 14 with its head 15, and the lock nut 21, are displaceable in the recessed portion 20 against the effect of the compression spring 17. If in such a manner of operation the circular knife 11 experiences a loading during a cutting operation due to the non-illustrated counterknife, the circular knife 11 can deflect due to the axial displacement of the fixation pin 14, which corresponds to the operating state with the spring-loaded circular knife.
If the extension 23 of the orifice plate 22 is in engagement with the lock nut 21, and hence the lock nut is fixed in position in the recessed portion 20 in an unmovable manner, the axial movement of the fixation pin 14 in the recessed portion 20 is also blocked, so that the head 15 of the fixation pin 14 rests against the circular knife 11 in an unmovable manner and hence securely holds the circular knife between the head 15 and the blade carrier 10. This corresponds to the manner of operation with the circular knife fixed in position.
With the embodiment illustrated in
The embodiment illustrated in
With the embodiment illustrated in
The features of the subject matter disclosed in the preceding specification, the claims, the abstract and the drawings can be important individually as well as in any desired combination with one another for realizing the various embodiments of the invention.
The specification incorporates by reference the disclosure of German priority document 10 2008 024361.2 filed May 20, 2008.
The present invention is, of course, in no way restricted to the specific disclosure of the specification and drawings, but also encompasses any modifications within the scope of the appended claims.
Number | Date | Country | Kind |
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10 2008 024361.2 | May 2008 | DE | national |