EP0219890A1 - Shift device - Google Patents

Abstract

In order to move cutting tools, pressure medium is let in between them and the respective shaft.

Description

The present invention relates to a device for changing the position of knives, in particular of lower knives for wrapped cutting when slitting paper, foil, tissue or similar web-like material with annular lower knives pushed onto at least one shaft or holders for these lower knives.

When slitting paper, fabric, foil, metals or the like, a distinction is made between the so-called straight cut and the so-called looped cut. In the case of the straight cut, the web to be cut into individual strips runs approximately tangentially between at least one upper and at least one lower knife, so that at least two strips result from a web in this way. However, not only a pair of knives, but also several pairs of knives can work together to cut a relatively wide web into a plurality of relatively narrow webs.

The end processor of the web to be cut often requests webs of different widths, which is why there is a need to cut a relatively wide web during one production process, for example into relatively wide webs and during another production process into relatively narrow webs. These cut webs are usually wound up into rolls, for example to be sent to the respective end processor of these railways in a simple and convenient manner.

The changing requirements of the end processor mean for those who have to subdivide a relatively wide web into individual webs that the facility available to them must be changed accordingly. This process is usually referred to as "positioning".

In the case of the so-called straight cut, it is relatively easy to position the lower and upper knives, since the web does not press against one of the two knives and impairs its mobility. In the case of the so-called looped cut, on the other hand, it is much more difficult to move the knife wrapped in the web, since the web presses against the lower knife due to the tension that is necessarily present in it for processing. The lower knife is thereby limited in its mobility, which is why it is particularly necessary in this case to ensure a smooth displacement of the lower knife when the position of this lower knife is to be changed.

From DE-AS 18 02 305 a device is known in which compressed air is pressed between the mutually displaceable parts of the slide guide of a knife. However, this known device requires a heavy, complex slide, which also requires an even more complex individual drive for each undercutter.

The device according to EP-A 96 026 (WO 83/02083) ver follows the goal of widening a hub. However, this aim is not aimed at by the proposed invention. A widening of knife hubs is not up for discussion in the proposed invention. This also applies to French patent application 23 40 170.

Based on the problem described, the task is to propose a simple and smooth-running device for moving the knives or their holders, in particular those knives or holders for the so-called lower knife, in particular in the event that the lower knife is at least partially from the is wrapped into a cutting web.

This object is achieved in that at least one radial bore is incorporated into each support of an undercutter or per undercutter in the shaft supporting the undercutter or supports, the exit points of this radial bore or these radial bores are arranged within the axial region of the shaft, which also at in the longitudinal direction of the shaft slight displacement of the holder or the lower knife is constantly covered by this holder or the lower knife, the exit points of the bores are positioned in the upper half of the shaft when the shaft is at a standstill, a positioning device which enables this positioning and can be brought into engagement a feed line for introducing pressure medium into the radial bores is provided.

The present invention makes it possible to make the lower knife in the radial direction with respect to it supporting shaft within the game due to the manufacturing so far that it can be easily moved in the axial direction of the shaft. This makes it possible to move relatively heavy lower knives, in particular so-called cutting sleeves, from one position to another with ease. This in turn makes it possible to switch the entire device in question from one type of production to another in a simple and quick manner, ie for example from a width of strips to be cut to another.

The proposed device is explained in more detail with reference to an exemplary embodiment schematically depicted in the attached figures, which does not limit the basic idea. In the present context, the essential parts of the machine are not shown in the drawing because of a clearer way of illustration, but rather only those parts are shown in the figures which are necessary for a more detailed explanation of the basic idea.

• Figur 1): Prinzipskizze des sog. geraden Schnittes
• Figur 2): Prinzipskizze des sog. umschlungenen Schnittes
• Figur 3): teilweiser Schnitt durch eine Untermesser unterstützende Welle
• Figur 4): Positioniereinrichtung für die das Untermes- ser unterstützende Welle
• Figur 5): Draufsicht auf die Einrichtung nach Figur 4

The individual figures mean:

• Figure 1): Sketch of the so-called straight cut
• Figure 2): Sketch of the so-called looped cut
• Figure 3): partial section through a lower knife supporting shaft
• Figure 4): Positioning device for the shaft supporting the lower knife
• Figure 5): Top view of the device according to Figure 4

In the device according to FIG. 1, a web 2 to be cut into several strips 1 runs through a pair of knives. Each pair of knives comprises an upper knife 3 and at least one lower knife 4. The upper knife (s) 3 is / are fastened on the shaft 5, while the lower knife (s) 4 are fastened on a shaft 6. Each of the shafts 5 or 6 is rotatably mounted in a correspondingly designed machine frame and can also be driven. For the purpose of changing their position, i.e. H. the width of strips 1 to be cut, the upper knives 3 can be displaced along the shaft 5 — that is, in the viewing direction of FIG. 1 — and the lower knives 4 along the shaft 6 as required. This shift can be relatively slight, especially if there are several intersecting points per undercutter. For example, bottom cutters can be designed in the form of so-called cutting sleeves, with each cutting sleeve containing a multiplicity of cutting edges. One and the same upper knife can optionally work together with each of these edges, so that it is often necessary in so-called format changes to move the upper knife by a relatively wide axial extent, while the lower knife only by a much shorter length, in order to enable this that the upper knife can work with another cutting edge, a so-called cutting groove, than before.

It can be seen from FIG. 2 that the web 2 and the strips 1 cut therefrom partially wrap around the lower knife or knives 4. In this way, the web to be cut is held better during the cutting process than in the case of the so-called straight cut according to FIG. 1. If the lower knife 4 in the case of the so-called 2 in the axial direction of the shaft 6 must be shifted, then the web 2 to be cut and the strips 1 cut therefrom press the lower knife or knives 4 due to the mechanical tension residing therein, their weight especially when it comes to it so-called cutting sleeves, is not to be neglected, against the shaft or the lower knife supporting shaft 6 and thus prevent the lower knife 4 from moving in the axial direction of the shaft 6, that is to say in the viewing direction of FIG. 2.

It can be seen from FIG. 3 that a plurality of lower knives 4a, 4b, 4c etc. can be arranged next to one another on each shaft 6. In addition, at least one axial bore 7 is machined into the shaft 6. At one end of the bore 7 there is a ball valve 8, the other end is closed by a screw 9. Radial bores 10, 11 and 12 open into the bore 7, the radially outer ends of which represent exit points from which the compressed air blown in via the ball valve 8 can escape. These exit points are designated 13, 14 and 15. The exit points 13, 14 and 15 in FIG. 3 are arranged approximately in the middle of the respective lower knife, so that even if the respective associated lower knife should be displaced within certain limits in the axial direction of the shaft 6, the respective exit point of the respective lower knife is constantly covered. In other words, this means that the respective lower knife can only be displaced relative to the shaft 6 to such an extent that this lower knife just barely covers the respective outlet opening.

The radial bores 10, 11 and 12 are incorporated in the shaft 6 such that they come to rest in the upper half 16 of this shaft when the shaft is at a standstill with a sectional representation of the shaft. In order to facilitate this, a positioning device is provided which enables the shaft 6 to be stopped in an easily possible manner immediately before the respective positioning of the lower knives 4 in such a way that the bores 10, 11 and 12 come to lie in the upper half 16.

The positioning device consists, for example, of a pawl 17 which can engage in a corresponding recess or groove 18 in the shaft 6. For example, the pawl 17 can be snapped into the bore 18 with the aid of a compression spring 19. With the aid of a cam 20, it is possible to disengage the pawl 17 from the bore or recess 18. It is possible to rotatably mount the cam 20 on a shaft 21 together with the latter and to rotate the shaft 21 with the aid of a hand lever 22. A switch 23 prevents the machine from starting in the event that the pawl 17 blocks the rotation of the shaft 6.

The bore 18 is preferably made at one end of the shaft 6 so that most of the shaft 6 remains free to position the lower knife thereon.

In addition to this mechanical possibility of positioning the shaft 6, it is conceivable to equip this shaft with a so-called angle encoder and in this way the shaft 6 in an electrical or electronic manner to be stopped together with a brake which can be switched on and off and which acts on the shaft 6 in such a way that the exit points 13, 14 and 15 of the bores 10, 11 and 12 essentially point upwards, that is to say are arranged in the upper half of the shaft 6. In this way it is possible, by introducing a pressure medium, such as compressed air, to raise the lower knives upwards by a small amount relative to the shaft 6 and to obtain a cushion of pressure medium, for example compressed air, on which the respective lower knife can be moved in a floating manner .

In this way it is possible to move even heavy cutting sleeves, which due to their own weight cannot be moved by an operator relative to the shaft 6 (knife shaft) by hand.

The knives or knife bushings can be shifted along the shaft 6 by both small and long distances, as long as only the respective knife covers the hole assigned to this knife. Due to the pressure medium emerging from the respective bore, in particular compressed air, the respective knife or the respective knife sleeve is raised by a small amount relative to the knife shaft and is able to slide on a thin cushion of pressure medium inserted between the shaft and knife. For this, it is not absolutely necessary to work special chambers into the inside of the knife, the knife sleeve or the knife holder for receiving the pressure medium. For example, it is also possible to use the knife, the lower knife sleeve or the knife holder to raise within the game that is already predetermined by the mechanical production of the machine parts involved.

It is also possible to have the respective upper knife work together with one edge during a certain cutting process and with another edge of the respective lower knife or the respective lower knife sleeve during another cutting process. This either increases the service life of the lower knife bushing or, with simultaneous displacement of the respective lower knife bushing relative to the upper knife, makes it easier to produce strips of different widths from materials to be cut from a web. In this way, the present invention aids in the changeover from one format to be cut and possibly wound up to another.

In addition, any cutting dust that may accumulate between the knife shaft and knife holder can be blown out of the device by the pressure medium, especially when using compressed air.

It is of little importance whether the respective lower knives or their holders in contact with the shaft 6 are relatively wide or relatively narrow, such as the lower knives 4a or 4c. It is also possible to each separate lower knife to be moved a separate supply of pressure medium z. B. to assign compressed air so that only this one lower knife or its holder can be axially displaced relative to the shaft 6, while the other lower knives on the shaft 6 maintain their position.

• 1 strip
• 2 lanes
• 3 upper knives
• 4 lower knives (4a, 4b, 4c etc.)
• 5 wave
• 6 wave
• 7 axial bore
• 8 ball valve
• 9 screw
• 10 radial bore
• 11 radial bore
• 12 radial bore
• 13 exit point
• 14 exit point
• 15 exit point
• 16 upper half of the shaft 6
• 17 jack
• 18 hole or recess
• 19 compression spring
• 20 cams
• 21 wave
• 22 hand lever
• 23 switches

Claims (1)

Device for changing the position of knives, in particular of lower knives for wrapped cuts when slitting paper, foil, tissue or the like at least one radial hole (10, 11, 12) is machined into the shaft (6) supporting the lower knife (4) or brackets, the exit points (13, 14, 15) of this radial hole (s) within that Axial region of the shaft (6) are arranged, which is constantly covered even in the longitudinal direction of the shaft slight displacement of the holder or the lower knife (4) by this holder or the lower knife (4), the exit points (13, 14, 15) When the shaft (6) is at a standstill, bores are positioned in the upper half (16) of the shaft (6), with the shaft (6) in egg allowing this positioning Positioning device (17-22) which can be brought into the vicinity and a feed line (8) for introducing pressure medium into the radial bores (10, 11, 12) are provided.

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